Publications Use the following field to search our publication database:
Determining an irrigation management plan in a furrow-irrigated rice production system
Year: Authors: Smyly A., Gholson D., Bond J., Bowman H., Bryant C.
Rice (Oryza sativa L.) is one of the most water demanding crops in the Southern United States due to rice typically being grown using a continuous flood production system. Mississippi River Valley alluvial aquifer (MRVAA) serves as a major irrigation water delivery source for rice farmers in the Mississippi Delta. Irrigation water is extensively withdrawn from the MRVAA, and the aquifer is beginning to deplete. Determining an efficient rice irrigation approach is vital to prolong the usage of the aquifer for agricultural needs. Research in Mississippi has shown furrow-irrigated rice (FIR) to produce rice with less water, but there is limited information on proper irrigation and fertilization strategies in FIR. This study was conducted to determine an irrigation management plan in FIR by evaluating rice response to different irrigation frequencies. Research was conducted at the Delta Research and Extension Center in Stoneville, MS on Sharkey clay soil in 2021 and 2022. Four irrigation frequencies (irrigating every day, every 3, 5, and 7 days) replicated three times were arranged using a randomized complete block design. WaterMark® Soil Moisture Sensors®, Pani-Pipes®, Precision King AgSense Sensors®, and flowmeters were used to collect soil moisture, water depth levels, and water usage data from each plot before and after every irrigation occurrence. Rice grain yield was determined for each treatment plot and zones within each plot. On average, irrigation plots in 2021 resulted in greater yields for plots irrigated every day, no difference in yields for plots irrigated every 3 or 5 days, and lower yields for plots irrigated every 7 days. However, 2022 yield data indicated no difference in yield across irrigated frequencies. In 2021, no difference was found in the combined average yield for all treatments between top, middle, and bottom zones. In 2022, top zone average yields were significantly greater from bottom zone average yields, but no difference was seen when compared to middle zone average yields. This research study will be conducted again in 2023.
The impact of inundation and nitrogen on common saltmarsh species using marsh organ experiments
Year: Authors: San Antonio K., Holifield M., Wu W., Huang H.
Sea level rise is an escalating threat to saltmarsh ecosystems as increased inundation can lead to decreased biomass, lowered productivity, and plant death. Another potential stressor is elevated nitrogen, which has a controversial impact on belowground biomass, potentially affecting the stability of saltmarshes and is relevant due to additional nitrogen brought into coastal regions via freshwater diversions. Our research objective is to examine the combined effects of inundation and nitrogen on common saltmarsh plants (Spartina alterniflora and Spartina patens). We set up two marsh organs with six rows and eight replicates in each row, one planted with S. alterniflora that occupies low, emergent marsh zones, the other with S. patens—a high marsh plant less tolerant of inundation and salinity. We randomly selected four replicates in each row to add 25 g/m2 of nitrogen in the form of ammonium nitrate every two or three weeks in the growing season. With the same frequency, we collected morphological characteristics such as plant height and leaf count to represent vegetation conditions in different dimensions over time. Furthermore, we harvested half of the marsh organ vegetation in Year 1 and the remaining in Year 2 to evaluate the short- and long-term impact of inundation and nitrogen on above- and belowground biomass (Year 2 belowground biomass still in processing). To help the inference, we developed multilevel Bayesian models. Our results show that inundation positively affected most of the characteristics of S. alterniflora measured over time while negatively affected S. patens, with both plants exhibiting some quadratic relationships for certain measurements and biomass. Exceptionally, leaf count and stem width of S. alterniflora showed maximum values at an intermediate inundation time, while stem width of S. patens reached the minimum at an intermediate inundation time. Aboveground biomass of both species responded to inundation differently in the short- and long-term. In the short-term, aboveground biomass of S. alterniflora reached the minimum at an intermediate inundation time, while there existed an optimum inundation time for long-term aboveground biomass and short-term belowground biomass. For S. patens, there existed an intermediate inundation level at which the short-term biomass reached the minimum, while inundation negatively affected long-term aboveground biomass and short-term belowground biomass. Additionally, for both species, plants with the nitrogen addition had higher aboveground biomass when compared to non-fertilized plants, while nitrogen addition had little to no impact on short term belowground biomass. This work will facilitate more-informed restoration and conservation efforts in coastal wetlands while accounting for climate change and sea-level rise.
Novel timing of EQIP 644 (Wetland Wildlife Habitat Management) enhances wetland structure and function on Delta row crop land
Year: Authors: Taylor J., Moore M., Hoeksema J., Locke M.
Important wetland properties associated with retention of excess nutrients and sediments in agricultural watersheds, as well as provision of critical food and habitat resources for migratory shorebirds, may be stimulated through novel implementation of existing wildlife BMPs in Lower Mississippi River Basin (LMRB) agroecosystems. We evaluated how novel timing (fall) of the implementation of NRCS EQIP 644 influenced nutrient runoff and denitrification in three inundated corn fields over a 3-month period. We observed significant positive N2-N flux rates (8 mg m2 h-1) soon after inundation that were sustained throughout the inundation period and culminated in an estimated 33-45 kg ha-1 of excess N removed by denitrification. We observed significant reductions in mean storm event loads for suspended sediments, NO3-N and PO4-P. We also observed significant reductions in TP loads, but NH4-N and TKN loads were not significantly affected by flooding. Flooded fields supported rapid colonization and maintenance of benthic macroinvertebrate densities (peak = ~5000 indv. m2) dominated by Chironomidae. Flooded fields provided critical habitat and food resources for migratory shorebirds with a minimum of 2100 individuals representing six shore bird species observed over four surveys during the fall migration period. Fields implementing shallow water habitat management in the fall had slight increases in soybean yields the following growing season. Our results suggest that novel timing of EQIP 644 provides temporary wetland structure and function that may support water quality improvements and provide critical shorebird habitat, without impacting yields within LMRB agroecosystems.
Occurrence and characteristics of microplastics in urban rainwater runoff and in oysters from the Mississippi Gulf Coast
Year: Authors: Cizdziel J., Wontor K.
Awareness of microplastics (MPs) as a global pollutant continues to grow among scientists, politicians, and the public. MPs are a diverse suite of contaminants that range in size from 1 μm to 5 mm and that occur in a variety of shapes. The Mississippi River acts as a conduit continually transporting plastic litter in runoff to the Gulf Coast where MPs accumulate and can affect susceptible organisms. Filter-feeding species, like oysters, are particularly vulnerable. The proportion of MPs in aquatic ecosystems stemming from urban runoff has grown with urbanization. Here we report our findings on MP pollution in runoff from parking lots and roads in Oxford, MS as well as in oysters (Crassostrea virginica) from the Mississippi Gulf Coast. We used a YSI ProSampler to collect rainwater runoff at set intervals during storm events, conducted a density separation to isolate MPs, and used stereomicroscopy and FTIR micro-spectroscopy to characterize the particles. We observed >150 MPs/L at the start of the rain event, with concentrations declining with time. Most MPs were fragments (~80%), followed by fibers (~18), and most (~80%) were <200 μm in size. MPs were mainly composed of polyethylene, polyester, polypropylene, polyvinyl chloride, and polystyrene. For oysters, locations inside bays near population centers had higher average concentrations. Oysters seem to accumulate more MPs on their external tissues than in their digestive system. MP concentrations in oysters was not correlated with oyster condition index. Further characterizing the types of MPs present in oysters may provide insight into likely sources of contamination at different sites. Overall, this work provides much-needed empirical data on the abundances and sizes of MPs in both urban runoff and in oysters from the Mississippi Sound, and suggests that lawmakers need to consider federal legislation to address MP pollution in river systems at a national level.
Impact of hydrological extremes on aboveground biomass of coastal wetlands
Year: Authors: Wu W., Feldpausch K.
Coastal wetlands are highly productive ecosystems that provide important ecosystem services and are threatened by extreme hydrological events. We evaluated how Bonnet Carré Spillway openings in Louisiana, US, affected vegetation productivity in coastal wetlands on the neighboring Mississippi Gulf Coast, US. Our study area is two estuarine systems that differ in their proximity to the Bonnet Carré Spillway, elevation, and salinity including Hancock County Marshes on the west, and Grand Bay National Estuarine Research Reserve (NERR) on the east in Mississippi. We collected above- and belowground biomass samples in 2020 and 2021, developed linear mixed-effects models to predict vegetation productivity based on spectral information of Landsat and Sentinel satellite images. We applied the models to hindcast vegetation productivity based on historical satellite images approximately during May and August of years with and without Bonnet Carré Spillway openings to assess the openings' impact on vegetation productivity. We found that as the frequency and duration of the Bonnet Carré Spillway openings increased, the peak green aboveground biomass decreased in both estuaries in the year when the spillway opened and was concentrated in the region that is closer in proximity to the Bonnet Carré Spillway. The research calls for development of flooding management strategies that could reduce the frequency and duration of Bonnet Carré Spillway openings.
Scour and stream stability at U.S. 98 over the Pearl River
Year: Authors: Quick K.
In February 2020, a major flood event occurred on the Pearl River that caused significant bridge scour, bank erosion, and the failure of existing streambank stabilization countermeasures at U.S. Highway 98 (US 98) near Columbia, MS. The Mississippi Department of Transportation (MDOT) maintains US 98, and in 2018 began planning and designing a new structure over the Pearl River to replace the 90-year-old eastbound bridge that was constructed in 1933. The US 98 westbound bridge was built in 1970 and was not originally scheduled to be replaced. The Pearl River is significantly meandering, and in 1986 MDOT constructed a series of five (5) jetties along the left descending channel bank to stabilize the lateral channel migration that was occurring immediately upstream of US 98. The 2020 flood caused significant scour along the jetty system, causing failure of one of the structures and severe bank erosion at a second structure. The scour along the jetties contributed to additional local scour at the US 98 bridge opening which led MDOT to implement a real time scour monitoring plan of action, and accelerated plans to replace the US 98 westbound bridge. This presentation will provide background for the US 98 bridge replacement project, lateral stream migration, and will discuss how technologies such as multi-beam bathymetric surveying, two-dimensional (2D) hydraulic modeling, and underwater acoustic imaging lead to a more informed and accurate decision-making process for MDOT. This will include both short-term and long-term plans to address stream and scour issues at the US 98 crossing over the Pearl River.
Cover crops can reduce irrigation water use in cotton
Year: Authors: Roberts C., Gholson D., Locke M., Spencer D., Steinriede R.W.
Improved cropping systems are needed to reduce irrigation water use of cotton where irrigation water is drawn from the declining Mississippi River Valley Alluvial Aquifer. A study conducted in Stoneville, MS, from 2021 to 2023 is assessing viable cropping systems for the mid-south to conserve irrigation water. Study treatments were established in the fall of 2020 and include reduced tillage, subsoil, winter fallow (RT); strip till, winter fallow; strip till, cover crop; strip till, subsoil, cover crop; no till, winter fallow; no till, cover crop; and no till, minimal surface disturbance subsoil, cover crop. Each treatment was individually irrigated based on tension-based soil moisture status. In the first year of full study implementation (2021), high amounts of timely rainfall made irrigation unneeded. Lint yield during that year was decreased in no-till treatments by up to 16% (1382 kg ha-1) compared to conventional reduced tillage (1647 kg ha-1). In 2022 precipitation was closer to normal. Cover crops improved soil moisture by as much as 47 kPa compared to the conventional, RT treatment. Compared to all winter fallow treatments, the treatments with a cover crop retained more soil moisture with soil moisture tension being 57% lower. This resulted in more irrigation water used in treatments with winter fallow. There were few differences in lint yield between the treatments, and yields were not improved by increased irrigation. Cover crops can be used to conserve water in cotton without reducing yield in years with normal precipitation.
Assessing the effect of land-use, land-cover change on surface water quality in Yazoo River basin
Year: Authors: Venishetty V., Parajuli P.B.
Water quality due to anthropogenic change of land use and land cover (LULC) had been the major factors for impairment. Developing a critical understanding in hydrologic and water quality outputs with change in LULC is essential. Therefore the main objective of this study is to assess the effect of LULC change on surface water quality in Yazoo River Basin (YRB). YRB is the largest watershed in the state of Mississippi, spanning over an area of about 50,000 Km2, with varied land-use conditions, quantifying the change in LULC through in-situ methods was not practical. Soil and Water Assessment Tool (SWAT) a GIS based modelling application was used in this study. LULC layers had been obtained from 2002 to 2019 for Mississippi, were used to simulate streamflow, sediment, total Nitrogen (TN) and total Phosphorus (TP). Model performance was good and satisfactory in predicting hydrologic and water quality outputs respectively. Significant LULC change had been observed for Pasture, forests, and wetlands. There was a decrease in pastureland, from about 39% in 2002 to 7% in 2019. Alternatively, increase in forest land was observed from 2002 to 2019 from about 15% to 30% and increase in wetlands from about 1% to 15%. With increase in vegetation, a decreasing trend had been observed in flow, sediment, and nutrient loads; from 2002 to 2019. Therefore, results from this study proves that there is significant impact on water quality and quantity with temporal LULC change. LULC change at watershed scale for YRB had never been conducted before, hence this study could be a novel addition that could help in optimal use of natural resources and improve water quality.
Utilizing 2-D hydraulic modeling for bank stabilization countermeasure design
Year: Authors: Buie T., Farmer M.
The Mississippi Department of Transportation (MDOT) has the responsibility to ensure the safety of the traveling public along Mississippi's highways and interstates. This includes highway crossings that occur over water. The riverine systems at these crossings are constantly evolving based on their own geomorphology and independent dynamic factors upstream and downstream of the site. The channel banks of these systems can become unstable due to stream migration and potentially threaten the bridge abutments and highway embankments. This presentation will explore two examples of countermeasures that MDOT plans to implement for bank stabilization throughout the state—Bendway Weirs and Longitudinal Fill Stone Toe Protection (LFSTP). Based on guidance from the Federal Highway Administration, these countermeasures are modeled using 2-dimensional (2D) modeling methods as opposed to 1-dimentional (1D) modeling due to the former resulting in greater detail around the countermeasures. Each of these countermeasures has their own design challenges, and the greater detail provided by 2D modeling processes provide a higher level of confidence in design.
Harmonizing Landsat-Sentinel-2 data for turbidity mapping in Mississippi Sound
Year: Authors: Martins V., Sparks E., Aires U.R. V. ., Rogers A., Doan L.
Satellite imaging systems have been widely used to support water quality and quantity management as it allows water quality analysis using empirical and semi-analytical relationship between optically active constituents (e.g., sediments, chlorophyll-a, dissolved organic matter) and spectral water reflectance. NASA Landsat 8/9 OLI and ESA Sentinel-2 MSI are the most relevant medium spatial resolution data sources for water applications, and the data harmonization from both optical sensors into a single data set, a so-called "virtual constellation", creates an unpreceded opportunity with a repeat frequency of ~ 3 days on average, and higher probability to obtain a cloud-free mapping of water constituents than Landsat or Sentinel-2 alone. This study developed a harmonized Landsat-Sentinel-2 framework for turbidity retrieval in Mississippi Sound. Standard top-of-atmosphere Landsat 8/9 OLI and Sentinel 2A/B MSI imagery were acquired with cloud cover lower than 50%, and both imagery were integrated in the same tile grid area. Cloud and shadow pixels were derived from Fmask algorithm and filtered as no data. We applied "Dark Spectrum Fitting" approach for atmospheric correction, and satellite-based water reflectance was used to model the water turbidity with USGS turbidity records on the Mississippi Gulf coast. The mapping results illustrate the complex freshwater inflow along the Mississippi Sound caused by Bonnet Carré Spillway openings, located about 28 miles northwest of New Orleans, and highlight the abrupt water quality changes in the oyster habitat. We showed the satellite observations are useful to complement the spatiotemporal analysis of recent water quality changes in the coastal region.
Irrigating corn on Sharkey clay soils using different furrow irrigation spacings
Year: Authors: Freeland T., Gholson D., Singh G., Kaur G., Larson E.
In the Mississippi Delta, over 40% of the farmland is classified as clay soils. Corn is mainly produced on sandy loam to silt loam textured soils. However, the recent economic returns on corn have led producers to start utilizing clay soils for corn production. Clay soils frequently flood and waterlog. Each day waterlogging occurs corn can lose between 5-30% of yield depending on the stage of growth. The overall objective of this research is to determine whether altering irrigated furrow spacings on Sharkey clay soils can reduce flooding and waterlogging to better benefit corn yield. The experimental design was a randomized complete block design with four replications. Furrow irrigation spacing treatments include every row irrigation, skip row irrigation, 4-row skip irrigation, and 8-row skip irrigation. The 4-row and 8-row skip treatments were further broken down to differentiate furrows that were irrigated and non-irrigated. They are noted as 4R-I, 4R-NI, 8R-I, and 8R-NI, respectively. Data on irrigation water applied, volumetric water content, plant population, plant heights, crop water stress index, multispectral imagery, corn yield, and grain quality are collected from this study. In 2021, the 4R-NI treatment yielded the highest in the trial at 177 bu/ac, while the 8R-NI had the lowest yield at 161 bu/ac. When looking at the volumetric water content in 2021, the 4-row skip treatments held the highest volumetric water content. The yield for the 2022 season was skewed by disease, so it will not be considered. In 2022, the skip row treatment held the highest volumetric water content. A third year will be conducted to further our understanding of the present data shown.
Hydraulic modeling: 1D or 2D in a 3D world
Year: Authors: Hendon D.
Hydraulic modeling is the process of using a numerical model to simulate flow in the real-world. This presentation will focus on 1D and 2D hydraulic models, as well as touch on CFD and physical scale models. Their similarities, differences, numerical schemes, and appropriate applications for each will be discussed.
Examining contemporary field rotation changes at wetland interfaces for industrial agricultural systems in the Yazoo-Mississippi Delta
Year: Authors: Heintzman L., McIntrye N.
Industrial agricultural systems are subject to land use/land cover (LULC) changes via field rotation. These pattern changes may consequently influence a diversity of embedded ecological processes. Even though wetlands—which are integral components of, and provide interfaces for, ecosystem services—are not directly subject to crop rotation, their structure (and, thus, function) may be shaped by LULC changes. Among the most productive North American agroecosystems, the Yazoo-Mississippi Delta (colloquially, "The Delta") exemplifies the challenges faced by these areas with dual aquatic and terrestrial status within mosaics of land ownership and legal protections. Although historical LULC within The Delta is well-documented, few studies have examined contemporary field rotation patterns and corresponding LULC effects on wetlands. To address this gap, we used NASS Cropland Data Layers from 2008–2021 to quantify LULC change around 43,524 wetland features in The Delta. We initially reclassified >35 LULC classes in the NASS data to nine mutually exclusive LULC types. We then identified 43,524 features which had been classified as wetlands during all focal years. For each of those wetland features, we buffered by 90m and grouped these results into four buffer size categories (small [x < 3.63 ha], medium [3.63 ha < x < 4.17 ha], large [4.17 ha < x < 9.25 ha], and extra-large [x > 9.25 ha]). We quantified LULC change within buffers of each wetland feature on a pixel-by-pixel basis, measuring LULC variety, majority LULC type, minority LULC type, and LULC stability (relative to baseline data from 2008). Overall, our results indicated that wetlands were dispersed throughout The Delta, with highest concentrations in Bolivar, Leflore, Sunflower, and Washington counties. LULC variety and stability were positively associated with spatial scale. Soybeans were the majority LULC type around wetlands at all spatial scales and years, indicating relative LULC stability around wetlands. LULC minority was other agriculture for medium, large, and extra-large categories. For the small category, LULC minority was wetlands- indicating isolation effects. Our study examined regional field rotation patterns and highlighted mixed management of wetlands in Delta agroecosystems. Our results indicate that wetlands of The Delta are especially subject to practices associated with soybeans. Our approach and results can be used to direct conservation efforts for ecosystem services and wetland resources. Additionally, our study augments emerging theory that dynamic landscape pattern management is necessary in industrial agricultural systems.
An analysis of storm events in a tailwater system in Sunflower County, MS
Year: Authors: Nelson A.
In the Mississippi Delta region, tailwater recovery (TWR) systems are an important best management practice to address both water quality and quantity issues. TWRs are surface water capture and irrigation reuse systems, using a combination of a ditch to capture surface water, an on-farm storage (OFS) reservoir to store captured surface water, and pumps to move surface water from the ditch into the OFS reservoir and to irrigate nearby fields. To determine if TWR systems are an effective way to reduce groundwater use, a ditch-only TWR system in Sunflower County, MS has been equipped with velocity and flow meters, auto-samplers, level loggers, and rain gauges. The objective of this long-term study is to determine a fully measured water budget for a closed TWR system. This is the first year of the study and an analysis of select storm events will be discussed.
Agriculture drainage water management: It isn't always what you think
Year: Authors: Maierhofer M., Huff D.
How does the lifecycle of a raindrop affect a crop? How do you know you have the right amount of water in the right place at the right time? We will discuss what water management encompasses and the benefits behind the different practices that may be misunderstood.
How can sub-surface water management work in your Southern ground?
Year: Authors: Maierhofer M., Huff D.
Take a deep dive into water management and how it can work in southern and Mississippi Delta soils, specifically sub-surface drainage and sub-surface irrigation. Contrary to popular belief, pairing these practices together can play an integral role in enhancing your farming practices. This presentation will focus on how each practice can be implemented in different soil types and how a system is designed.
On-Farm Mississippi Delta and Southeast trials: What we've learned and the data findings
Year: Authors: Huff D., Maierhofer M., Henderson C., Miles M.
Presentation will focus on how these practices can benefit southern farmers from southern farmers. What have we learned from our trials from the last couple of years and where do we go from here.
Microbial water quality of agricultural water systems in Mississippi and Alabama: The risks to fresh produce
Year: Authors: Bond R.F., Silva J.L., Abdallah-Ruiz A., Atwill E.R.
Irrigation is an important practice for agriculture in Mississippi and Alabama, but the use of contaminated water can lead to the spread of harmful microorganisms. This study was conducted through the 2018-2019 produce season to evaluate the microbial water quality of irrigation water in both states by analyzing samples from different agricultural water systems. We measured the levels of indicator microorganisms such as enterococcus, fecal coliforms, and Escherichia coli (E. coli) as well as pathogens such as Salmonella, Shiga-toxin producing E. coli and E. coli O157:H7. With this understanding we will provide insight into the potential health risks associated with the use of irrigation water in Mississippi and Alabama and will inform recommendations for improving water quality in these systems. Additionally, we investigated identifying these sources of contamination and worked to develop strategies to reduce the spread of harmful microorganisms in irrigation water.
Evaluation of sector control variable rate irrigation (VRI) on a production field
Year: Authors: Green Z., Tagert M.L., Paz J., Lo T.
Mississippi's average annual precipitation is approximately 127 cm, of which 70% occurs in the winter and spring months outside of the growing season. Accordingly, an increasing number of on farm water storage (OFWS) systems have been built in northeast Mississippi in recent years. These systems capture and store off-season precipitation and runoff that can later be used for irrigation. With limited rainfall during the growing season, farmers solely dependent on surface water have a finite amount of water to use for irrigation through the growing season and therefore must irrigate efficiently. This study evaluates the costs and benefits of sector control variable rate irrigation (VRI) on an 18-hectare corn and soybean production field under sprinkler irrigation in Noxubee County. During the 2022 growing season, corn was planted on April 25 and harvested on August 20. Elevation, yield, and soil moisture data collected from 2018-2021 were analyzed in Esri's ArcMap software, and two irrigation management zones were created in the field. A soils layer was not included in this geospatial analysis because previous gridded soil sampling confirmed a homogeneous soil type of silty clay loam with small areas of silt loam. A 'dry' irrigation management zone was placed in the southern section of the field, and a 'wet' irrigation management zone was placed in the northwestern section of the field. Each management zone is approximately one quarter of the area under the center pivot. Each zone was then sub-divided into six different pie-shaped sectors. The three control sectors received 1.9 cm of water, which was the conventional amount of irrigation applied by the farmer. The other three test sectors received 1.5 cm of water, which was a 20% reduction from the conventional amount. The center pivot is equipped with a Linsdsay Growsmart IM3000 magnetic flow meter to measure water use. Two sets of Watermark 200SS granular matrix soil moisture sensors were placed in the centroid of each sector at depths of 30 and 61 cm to measure soil water tension throughout the growing season, and sensors were removed just before harvest. Yield data was recently obtained from the farmer, and soil tension data is currently being analyzed with yield data to determine if water savings were realized without a loss in yield. This presentation will include preliminary results from this multi-year study.
Second year: Overhead irrigation and nitrogen rates effects on corn water use and yield response based on soil-moisture sensors thresholds
Year: Authors: Vargas A., Gholson D., Lo H., Singh G., Krutz J.
Groundwater is the most exploited resource for furrow irrigation in Mississippi. The overuse and excessive pumping from agriculture and fisheries have exceeded the natural water recharge of the Mississippi River Valley Alluvial Aquifer. Limited research is available on using overhead irrigation systems in corn production systems in the Mississippi Delta. Therefore, understanding the relation between sensor-based irrigation scheduling and nitrogen management using a lateral move system is essential to effectively apply water and nitrogen (N) for sustainable production. The objective of this study was to evaluate the effects of sensor-based irrigation with different nitrogen rates on corn yield. This is our second year, the field was established at Delta Research and Extension Center, Mississippi State University, Stoneville, MS in 2022. Treatments included in this study were three irrigation scheduling thresholds (-40, -70, and -100 kPa) and a rainfed treatment, four N rate applications (0, 112.3, 224.5, and 336.8 kg ha-1), and two distinct soil textural classes (Sandy Loam and Clay). Data collected included SPAD meter readings, grain N uptake, corn grain yield, and irrigation water use efficiency. Results will be presented at the conference. Corn grain yield was adjusted to 15.5% moisture prior to analysis. Data was analyzed using the GLIMMIX procedure in SAS statistical software at a p-value of 0.10. The results of this research will be presented at the conference.
Modeling hydrologic alteration in Northern Gulf Coast river basins
Year: Authors: Roland V., Crowley-Ornelas E.
In recent history, interest in the conservation of riverine ecosystems has grown as people have become more knowledgeable about the functions of these habitats. Anthropogenic hydrologic alteration is a direct threat to the health of these ecosystems because it often triggers a range of negative effects on the biological, physical, chemical, and hydrologic characteristics of impacted waters. Understanding important factors and drivers of hydrologic alteration is essential to the planning effective conservation action plans. This study explores the application of machine learning to predicting hydrologic alteration and identifying important predictors of hydrologic alteration in the Pearl and Pascagoula River Basins in Mississippi. Modeled daily streamflow for 12-digits hydrologic unit code (HUC12) watershed pour points was used to compute the net change in streamflow volume and to conduct a confidence interval hypothesis test across pre- and post-alteration periods between 1950 and 2009. Cubist models were developed for each basin to predict the p value of the confidence interval test as a function of the net change and a range of other physical and meteorological watershed parameters. Analysis of the net change and confidence interval test results indicated the basins had similar amount of altered HUC12 watersheds. Moreover, patterns of altered watersheds tended to coincide with the locations of densely populated areas, dams, and in areas with substantial land cover change in both basins. The cubist models developed for the basins produced accurate predictions of the confidence interval test results in most HUC12 watersheds. The importance of model predictors demonstrated differences in the relationships between basin geomorphology, land cover, and hydrologic alteration in the basins. The results of this study are evidence of the potential of the cubist algorithm in hydrologic alteration assessments. More broadly, machine learning and other data driven approaches can be applied to a variety of complex water resources issues to inform local, state, and federal resource managers.
Development of a two-dimensional hybrid sediment transport model
Year: Authors: Zhang Y., Al-Hamdan M., Bingner R., Wren D.
The Sediment transport, defined as sediment driven by water and moving in water, is one of the most important processes when studying morphological and environmental problems. Sediment transport may result in sediment deposition in lakes, reservoirs and coastal wetlands; erosions along riverbanks, coastal lines, and at downstream of dams; local scour downstream of hydraulic structures; gully erosion in agricultural lands; channel evolution; adsorption/de-adsorption and resuspension, etc. In addition to conventional physical models, with the advancement of computer technology and numerical methods, numerical models have become powerful tools to study sediment transport in water bodies such as rivers, lakes, reservoirs, and coastlines. This paper presents the development of a two-dimensional hydrodynamic sediment transport model. The model is a single-phase, non-equilibrium, and non-uniform sediment transport model for unsteady turbulent flows, considering multiple sediment transport processes, such as deposition, erosion, transportation, and bed sorting. The governing equations for the flow and the sediment transport are discretized on an unstructured hybrid mesh system consisting of triangle and quadrilateral cells, which is more suitable for geometrically complex domains with higher adaptivity compared to the structured mesh system. Selected examples and applications will be used to demonstrate and validate the newly-developed sediment transport model
Baseline flow, gage analysis, and on-line tool development supporting bay and estuary restoration in Gulf States
Year: Authors: Rodgers K.
The U.S. Geological Survey in cooperation with the Gulf Coast Ecosystem Restoration Council and the U.S. EPA are collaborating to assess the climatic, physiographic, and anthropogenic factors driving spatial variability and temporal trends in the freshwater delivery to the Gulf of Mexico. The timing and magnitude of freshwater delivery influences terrestrial and aquatic communities, changing community composition and altering habitats necessary to support indigenous life. The 9-year, 8.9 million dollar projects examine multiple aspects of streamflow including streamflow trends, alteration of flow, lowflow statistics, and flow-ecology relationships in the southeast United States. Data produced as part of the Baseline Flow study is served on the RESTORE Data Visualization tool which utilizes modern web technologies and numerous free and open-source software (FOSS) libraries to provide user with an engaging experience through a high degree of interactivity and responsiveness. The web application provides a map-based interface for viewing spatial patterns of basin characteristics, streamflow statistics, and various metrics of flow alteration across the Gulf Coast region.
Identification and evaluation of ponds under climate change scenarios
Year: Authors: Nepal D., Parajuli P.B.
Ponds have the capacity to regulate and store water, helping to reduce the effects of droughts and floods. They can recharge groundwater aquifers and enhance water quality by capturing sediments and nutrients. This study aims to identify the ponds within Big Sunflower River Watershed (BSRW) using Google Earth Engine (GEE) and evaluate the effects of projected climate change on hydrological process in ponds using Soil and Water Assessment Tool (SWAT). The model was calibrated and validated against streamflow, groundwater level changes, and sediments with acceptable model accuracies. Downscaled future precipitation and temperature data were generated by using Climate Model data for hydrologic modeling (CMhyd) tool. The future climate scenario was generated for Representative Concentration Pathway (RCP) 8.5 of the global climate model Geophysical Fluid Dynamics Laboratory Earth System Model 2M (GFDL-ESM2M) for mid-century (2040-2060) and late century (2079-2099). In the mid-century, increase in the annual average maximum and minimum temperatures were observed by 6% and 13% respectively; whereas increase in the annual average precipitation were observed by 26% as compare to the baseline condition. Similarly, 15% and 28% rise in the annual average maximum and minimum temperatures along with a 24% increase in the annual average precipitation in the late century were observed as compared to the baseline. This study was expected to demonstrate that the ponds will be able to capture runoff, reduce erosion, and contribute to aquifers recharge. However, the results will also indicate that the effectiveness of ponds are impacted by changing climatic circumstances. The results of this study will be useful for the development of plans for managing and preserving the pond ecosystem in the face of climate change by enabling an understanding of the interaction between hydrology, land use and climate change.
Climate change impacts on coastal watershed streamflow
Year: Authors: Bhattarai S., Parajuli P.B., To F.
In this study, the variation in streamflow due to climate change was assessed at two coastal watersheds: Wolf River Watershed (WRW) and Jourdan River Watershed (JRW) of Mississippi. The Soil and Water Assessment Tool (SWAT) model was used to simulate the hydrology of WRW and JRW. Further, the flood frequency of the simulated peak flow events was analyzed. The baseline models for both watersheds were auto-calibrated with SWAT-Calibration and Uncertainty Programs (SWAT-CUP). Kling-Gupta Efficiency (KGE) ranges from 0.8 to 0.7 in WRW and from 0.55 to 0.68 in JRW during model calibration-validation. Results in WRW indicated that the monthly average baseline flow was 1% greater than historical and 8.88% less than future climate. Likewise, monthly average baseline flow was 10.9% greater than historical and 5.73% less than future climate in JRW. Annual maximum series and partial distribution series of all climatic conditions were fitted to Log-Pearson Type-III distribution to analyze and compare flood frequency. Thus, this study could support watershed managers and planners to prepare for flood occurrence likelihood in the future.
HOST model framework for analysis of hydrologic drought patterns over the Southeast US
Year: Authors: Raczynski K., Dyer J.
Drought is a complex phenomenon that is difficult to predict due to the variety of associated environmental drivers; however, its cyclic reoccurrence provides a basis for time-scale pattern analysis. The time factor reflects a complex structure of meteorological, geological, and surface factors affecting the specific way that drought develops in each region. In terms of the precipitation to evaporation ratio, seasonal dry periods indicate a time of increased probability for hydrological drought to form; however, underground water inertia within a region might affect the process in the opposite way, depending on the aquifer stage and general impact on runoff. The combination of long- and short-term changes in runoff structure might provide valuable insights into drought risk assessment and, especially due to climate change, improve the recognition of temporal patterns of drought occurrence. The objective of this work is to apply the Harmonic Oscillator Seasonality-Trend (HOST) model framework to analysis of hydrologic drought patterns, using a simulated streamflow dataset covering the Southeast US. Daily flow data from the National Water Model retrospective dataset v.2.1 were used for the period Feb. 1979–Dec. 2020, which provides long-term simulated streamflow data at a high spatial resolution across the study region . Droughts are identified using an objective threshold approach and aggregated on monthly scales. The temporal changes are assessed by a set of superimposed harmonic functions calculated for decomposed time series, representing drought occurrences and minimal flows. The HOST model can capture and reflect drought patterns on both short- and long-term time scales, with the first reflecting annual precipitation patterns and the second occurring close to the El Nino-Southern Oscillation cycle. Input data are divided with a 70/30 split for training and testing, respectively. Results are evaluated using contingency statistics and indicate about 80% accuracy for trained models (with an IQR between 74% and 87%) and around 60% accuracy in testing sets (with an IQR between 47% and 76%). In terms of spatial distribution, areas in southern Mississippi and eastern South Carolina are identified as regions with extended function periods, indicating prolongation of dry conditions. The work presents an early stage of model software development and initial results, with current limitations identified and discussed.
Quantification of a century-long stream and aquifer water exchange in the Mississippi embayment under a changing climate
Year: Authors: Ouyang Y., Wei J.
Groundwater depletion due to the increasing water demand for agricultural, domestic, and industrial usages under a changing climate is a critical concern worldwide. Many regions of the world are now experiencing a certain degree of groundwater resource depletion. Mississippi Embayment (ME), encompassing parts of Missouri, Illinois, Kentucky, Arkansas, Tennessee, Mississippi, Alabama, and Louisiana, is an intensive crop production region in midsouth US and is one of the fastest groundwater resource depletion regions in the world. An understanding of the long-term stream and aquifer water exchange is crucial to groundwater resource planning, allocation, and management in the ME. Using the US Geological Survey's MERAS (Mississippi Embayment Regional Aquifer Study) groundwater model, we estimated the stream and aquifer water exchange in the ME over a 115-year simulation period from 1900 to 2014 under the following six different scenarios: (1) a base case scenario represents the current agricultural practices, groundwater pumping, and natural conditions existing in the ME; (2) an extreme wet scenario that is the same as the base case scenario except that the precipitation rate is increased by 20%; (3) an extreme dry scenario that is the same as the base case scenario except that the precipitation rate is decreased by 20%; (4) a no-pumping scenario that is the same as the base case scenario except without groundwater pumping; (5) a scenario without pumping with 20% increase in precipitation, which is the same as the extreme wet scenario except for without groundwater pumping; and (6) a scenario without pumping with 20% decrease in precipitation, which is the same as the extreme dry scenario except for without groundwater pumping. Simulations showed that more waters leaked from the aquifers to the streams than from the streams flowed into the aquifers over the past 115 years. There was about 3 times more aquifer water leaked to the streams without pumping than with pumping. Our study suggested that the groundwater pumping rather than the extreme precipitation played a vital role in stream and aquifer water exchange of the ME.
Proposing a coupled hydroeconomic model for the Mississippi Delta of the Mississippi River Valley Alluvial Aquifer (MRVAA)
Year: Authors: Maskey M.L., Al-Sudani A., Nelson A.M., Quintana Ashwell N.
The Mississippi Delta is one of the largest contiguous agricultural production areas in the United States. Overlying an alluvial plain, this area is known for producing row crops such as cotton, soybeans, and corn, as well as rice and catfish. Therefore, this region is a major economic contributor to the state and nation, with $6.8 billion in annual agriculture revenue. The Delta receives over 54 inches of rain annually, but most of that precipitation occurs outside the growing season. Consequently, the region depends on irrigation to sustain agricultural production in the state largely depends on. Over time, the number of wells has expanded to meet abundant and accessible water of sufficient quality for the ever-increasing expansion of irrigated acreage. According to the Mississippi Department of Environmental Quality, the number of permitted wells increased from 10,571 to 21,000 between 2000 and 2022. As a result, groundwater levels in the shallow Mississippi River Valley aquifer have declined. However, data gaps make it difficult to interpret water conditions in this alluvial aquifer, which limits the ability to make realistic recommendations. Therefore, we propose a protocol to develop a coupled groundwater model that incorporates hydrologic dynamics and economic behavior in the presence of surface water sources. Therefore, we propose a protocol to develop a coupled groundwater model that incorporates hydrologic dynamics and economic behavior in the presence of surface water sources. This protocol addresses different agricultural management practices to study groundwater and surface water interactions. Additionally, the integrated groundwater model will be used to optimize water delivery costs, crop yields, and extraction from existing wells. We propose an economic modeling tool widely used in policy analysis: "Positive Mathematical Programming," that replicates observed economic behavior under alternative hydroeconomic circumstances. At this stage, we present a conceptual framework to develop the integrated modeling platform with the available data. We also plan to extend this study by generating historical and future plausible scenarios that will inform decision-makers about viable strategies to address groundwater concerns in the Delta. We envision that this research will serve as a multi-benefit protocol in a) generating timeseries of groundwater data from the past to the future, to understand subsurface dynamics; b) optimizing groundwater well extraction levels under different land use, agriculture management practices and climate conditions; and c) informing feasible water delivery costs, crop yields, and groundwater withdrawal under sustainable aquifer conditions.
Numerical study of groundwater transfer and injection pilot project in the Mississippi River Valley alluvial aquifer using a groundwater model with NLDAS and airborne resistivity data
Year: Authors: Fang J., Al-Hamdan M., O'Reilly A., Ozeren Y., Rigby J.
Sustainable groundwater management is a topic of interest in the Mississippi River Valley alluvial aquifer (MRVAA) where declines in groundwater levels have been reported over the last few decades. To find a solution to this problem, the Groundwater Transfer and Injection Pilot (GTIP) project is being conducted at Shellmound, Mississippi, by the U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), National Sedimentation Laboratory. The managed aquifer recharge (MAR) technology being tested takes source water acquired via riverbank filtration and then transfers and injects the water into a depleted section of the MRVAA. Field measurements are essential to the GTIP project for assessment of the feasibility of this MAR technology, while numerical modeling is important for the evaluation of potential designs. Therefore, a numerical groundwater model was developed for this pilot study site. In this area, the vadose zone of the MRVAA consists mainly of fine-grained sediments. Our numerical experiments revealed that the hydraulic properties of the unsaturated soil can significantly affect the hydrological processes controlling groundwater pumping during riverbank filtration and groundwater injection in the aquifer. Hence, in this study, precipitation, evapotranspiration and soil moisture data from the North American Land Data Assimilation System (NLDAS) were used to estimate the soil properties in the vadose zone through data assimilation. The estimated unsaturated soil properties were then implemented into the groundwater model in which aquifer resistivity data derived from airborne geophysical surveys by USGS were incorporated to consider the spatial variability of the aquifer hydraulic conductivity. An empirical formula was applied to translating the resistivity data into hydraulic conductivity. The coefficients in the empirical formula were determined by calibration of the numerical model with the measured groundwater hydraulic heads. Good agreement was found between the simulation results and the field data in both calibration and validation periods, indicating the potential of using this modeling technique to facilitate decision-making on the potential implementation of the MAR technology being tested by the GTIP project.
Agrogeophysical methods for mapping internal erosion soil pipes
Year: Authors: Wodajo L., Rad P., Islam S., Hickey C., Wilson G.
Ephemeral gullies result from the junction of rills that form a branching or tree-like pattern of channels. They can also be formed by internal erosion that leads to pipe (tunnel) collapse. These gullies usually appear on a cultivated field during the planting or growing season and can be partially or totally erased and filled by tillage operations. The filling leaves the nutrient-rich topsoil vulnerable to erosion leading to soil deterioration and poor crop production over a larger area than the gully itself. This paper evaluates the feasibility and efficiency of two geophysical methods, ground penetrating radar (GPR) and electromagnetic induction (EMI), for delineating soil pipes in cross-sectional and plan-view maps. The study site, currently used for pasture and crop production, is located within the Goodwin Creek experimental watershed (GCEW) of North Mississippi. The area is affected by multiple pipe collapse features, such as flute holes, sinkholes, and small to large gully windows. The erosion pipes are located at a shallow depth of less than 2m with varying lengths and widths. Geophysical signatures from the two methods are evaluated using a composite (combined) cross-section plot that includes results of an invasive technique known as cone penetrologger testing (CPL). These signatures are then used to construct plan-view maps of the area. The EMI results allow for the delineation of larger zones of fields having soil pipe networks. The GPR data provides a much better resolution. The GPR data can be used to construct maps (depth slices) representing different depths. The results demonstrate the high potential of EMI and GPR as valuable tools for studying internal soil pipes. This work was supported by the U.S. Department of Agriculture under Non-Assistance Cooperative Agreement 58-6060-6-009. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the U. S. Department of Agriculture.
Using the EPA Stormwater Management Model to evaluate efficacy of green infrastructure on mitigating flooding in an underrepresented coastal community
Year: Authors: Holifield M., Wu W.
Frequent flooding is dangerous to both short- and long-term health, and the expenses of constant repair and upkeep wear down both citizens and city government. Moss Point, Mississippi is an underrepresented and marginalized community on the coast, well known for its frequent flooding for the last few decades. As global climate change shifts local weather patterns towards heavier rainfall and more intense tropical storms, stormwater management becomes a pressing issue concerning existing grey infrastructure. Green infrastructure has shown efficacy in mitigating flood risks while providing other co-benefits such as habitats, carbon sequestration and improved air and water quality, and can be affordable in construction and maintenance. Here we evaluated the impact of low-cost rain garden and high-cost permeable pavement on peak runoff and total runoff in three areas that are most vulnerable to flooding using the EPA's Storm Water Management Model (SWMM). The preliminary results show that both rain garden and permeable pavement led to more reduction in peak and total runoff in the more suburban catchment than in the more rural catchment. In the same catchment, permeable pavement showed more reduction of runoff than rain garden. Permeable pavement could reduce total runoff up to 21% in total runoff and 17% in peak runoff, while the percentages of reduction for rain garden were up to 1.3% and 3.8% respectively. Combining these two types of infrastructure showed effect dominated by permeable pavement. However, permeable pavement can be extraordinarily expensive, and its replacement of existing infrastructure is unrealistic. Future analysis will focus on evaluating additional green infrastructure types with different design parameters individually and combined with multiple storm event intensities. The research will facilitate implementation of low-maintenance green infrastructure in the city of Moss Point to mitigate flood risks.
Numerical simulation of flow, sediment and nutrients in upland watersheds and downstream channel networks
Year: Authors: Chao X., Al-Hamdan M., Bingner R., Zhang Y., Witthaus L.
Goodwin Creek Experimental Watershed (GCEW) located in Panola County, Mississippi, is a 21.3 square kilometers Conservation Effects Assessment Project (CEAP) benchmark watershed monitored by USDA-ARS National Sedimentation Laboratory (NSL). The main concern in this watershed is soil erosion due to rainfall and runoff in the upland fields. In addition, the sediment associated nutrients are also transported into downstream channel networks due to soil erosion. The Annualized Agricultural Non-Point Source (AnnAGNPS) watershed model, developed at the NSL, was applied to simulate the loads of water, sediment and nutrients from the upland fields of GCEW. In this model, the effects of land use/land cover, soil properties, climate, agriculture management, etc. on the watershed loads were considered. The results produced from AnnAGNPS were used as boundary conditions for the Center for Computational Hydroscience and Engineering 1-Dimensional (CCHE1D) model developed at the National Center for Computational Hydroscience and Engineering, to simulate the flow, sediment, and nutrients in downstream evolving channel networks of GCEW. This model computes the non-equilibrium sediment transport with non-uniform size mixtures. It can also simulate the transport and fate of nutrients and other pollutants in channel networks, including the biogeochemical reactions that take place in the streams and sediment bed layers. Simulated results were calibrated and validated using field measured data collected by the NSL. This research provides useful tools to assess the impacts of upland sediment and nutrient loads on the downstream channel networks.
Using two-dimensional modeling to enhance hydraulic design
Year: Authors: Carlisle A.
The presentation will review several case studies in which the hydraulic analysis and design was improved using two-dimensional hydraulic modeling. The Standard for Hydraulic Modeling is a One-Dimensional Modeling Routine developed by USACE Hydrologic Engineering Center (HEC-RAS, HEC River Analysis System). The model computes water surface elevations (WSE) by solving the energy equation using a standard step method between cross sections, using inputs such as geometry (cross section data), roughness Parameters (Manning "N" values), boundary conditions, and discharge/flow data (steady or unsteady). The model predicts average WSE and velocity for the cross section, main channel, and both overbanks. Certain site-specific conditions can present challenges when using 1D modeling, including a) project areas with flood flows that vary spatially, b) floodplain encroachments with skewed alignments to overall floodplain, c) Modeling multiple openings within one floodplain, and d) assessing and quantifying lateral discharge. When these constraints arise, 2D modeling can improve the modeling and subsequent design. The 2Dhydraulic models include the generation of a mesh with variable number of elements over the project domain, and computes hydraulic parameters at each element node using a finite volume approach. (HEC-RAS 2D, SRH-2D, FLO-2D, Others). The 2D models aide with the challenging constraints mentioned above. Other advantages include assessing the impact of flood storage in project domain, and the impact of floodplain encroachment ineffective flow area zones (useful in bridge scour / approach XS estimation). 2D models utilize similar inputs as 1D, including discharge data, boundary conditions, terrain (geometry), and roughness Parameters (Manning's "n"). Within 2D models, the terrain and roughness inputs are included for the entire project domain (floodplain) instead of at specific cross section locations (1D). For terrain, utilize available LiDAR elevation data and merge with field survey topographic data. This creates a mesh with elements to simulate actual field conditions. or roughness parameters, the National Land Cover Datasets can be used for large project domains or digitize roughness polygons for smaller domains. It is noted that 1D models are still utilized to obtain boundary conditions for the 2D analyses. In this presentation, we will review four case studies to demonstrate examples of each application below and discuss how 2D capabilities improved the hydraulic modeling at each Case Study. <ol><li>Subject areas with flood flows that vary spatially.</li> <li>Floodplain encroachments with skewed alignments to overall floodplain.</li> <li>Modeling multiple openings with floodplain.</li> <li>Assessing and quantifying lateral discharge.</li> </ol>
Wisdom from wastewater: Lessons learned from a SARS-CoV-2 wastewater monitoring program
Year: Authors: Gitter A., Bauer C., Wu F., Chavarria C., Mena K.
Community-specific wastewater monitoring programs gained international attention during the COVID-19 pandemic due to their ability to detect SARS-CoV-2 genes in wastewater and consistently predict spikes in clinical cases one to three weeks in advance. The border city of El Paso, Texas - a predominantly Hispanic community with nearly 52% of its population experiencing a low socioeconomic status- acutely suffered from the COVID-19 pandemic. In April 2020, the water utility, El Paso Water, initiated a SARS-CoV-2 wastewater monitoring program to assess virus trends and the appropriateness of a wastewater monitoring program for the binational city. Weekly sample collection continues to occur at four wastewater treatment facilities, serving distinct regions of the city. Previous work analyzing SARS-CoV-2 genes using the CDC 2019-Novel coronavirus Real-Time RT-PCR diagnostic panel identified a lag time between virus concentrations in wastewater and reported COVID-19 case rates ranging from 4 to 24 days. While the wastewater monitoring program at El Paso Water continues to expand (now monitoring for 10 viral pathogens), a critical need remains to translate wastewater data for public health preparedness and community health needs. Engaging local communities to identify public health concerns and experiences, through community health workers and surveys, will be needed to not only inform future wastewater monitoring directions, but also develop trust in the science. Additionally, utilizing quantitative microbial risk assessment to evaluate population-level health risks and potentially establish baseline concentrations for pathogens in wastewater (i.e., SARS-CoV-2) should be pursued. Establishing a framework for collecting, monitoring, translating and disseminating wastewater data will assist disease prevention efforts in the region. Wastewater is a critical resource to meet not only the limited water supply needs of El Paso, located in the arid Chihuahuan Desert, but also the public health needs of its community.
Off the grid, single family residential, self contained water system
Year: Authors: Ford G., Rokooei S., Garshasby M.
Recent incidents in Scottsdale and Rio Verde Foothills, Arizona regarding water use in single family dwellings has drawn renewed national attention to climate change, population growth and limited resources on a community-sized scale with real, immediate effects on the residents of this community. Suffering from a long-term drought, the city of Scottsdale administrators are concerned about water supplies for their residents. This concern has resulted in cutting off tanker transported, water supplies for 500 neighboring Rio Verde Foothills homes. Rio Verde Foothills residents have already initiated legal action against the City of Scottsdale. What other alternatives do the Rio Verde Foothills residents have? Local building codes regarding water supplies for single family residences generally specify water requirements, but can a practical, waterless home be built for arid or overpopulated regions? This paper discusses the potential designs for waterless or near waterless homes. Water for drinking, bathing and bathroom uses are typically needed end uses, at a minimum. Potential designs providing for these end uses for single family homes in several different regions of the United States are discussed. Maintenance and installation costs, and ease of installation and maintenance are the primary considerations.
Simulation of steady-state groundwater flow and evaluation of groundwater level fluctuations in the Mississippi Delta using GMS-MODFLOW
Year: Authors: Nekooei M., Paz J.
In recent years, significant water withdrawal from the Mississippi River Valley Alluvial Aquifer (MRVA) for irrigated agriculture in the Mississippi Delta region have caused considerable declines in aquifer water levels, to the extent that withdrawals have outstripped the recharge. Therefore, water managers have a major concern about the ability of aquifers to meet increasing water demand in the Delta. In this research, the MODFLOW groundwater flow model with GMS software was used to compare the simulated daily groundwater levels with the water-level measurements in the period of the growing season from April through September between 2016 to 2021. The daily groundwater data for 11 observation wells were collected from USGS for the period, along with a few available pumping data from the irrigated wells in the Delta. In addition, the data for areal recharge, rivers, adjacent aquifers, boundaries, and the characteristics of the aquifer were considered as the other GMS packages to construct the model. The discretized was established by using a single layer rectangular-grid and oriented north-south with 1-kilometer square cells to represent the alluvial aquifer. The part of the grid covering the Delta area has 76,039 active cells. The model-generated April to September water levels for each year of the simulation were compared to the corresponding measured water levels. The average root-mean-square (RMS) error determined for the calibrated model was 1.4 meter. Assessing the daily data, a declining trend in groundwater levels was observed during the growing season throughout the studied area. However, the aquifer experienced a more reduction in the water table in 2016 and 2017 in comparison with the other years. In addition, the counties of Sunflower, Leflore, and Washington experienced more fluctuations in the water table due to the excessive withdrawals. Overall, the model results indicated that the simulated hydrographs in all the wells are reasonable representations of the measured water levels. A long-term modeling scenario that assumes the same 2021 pumping rate will likely result in the depletion of grid cells located in the three counties. Based on the model results, the net recharge from the Mississippi River and from the adjacent aquifers was small.
Prediction of dissolved phosphorus concentrations in the high plains aquifer region using a boosted regression tree framework
Year: Authors: Temple J.M., Paul V.
Groundwater-derived phosphorus (P) has often been dismissed as a significant contributor towards surface water eutrophication, however, this dismissal is unwarranted, making the quantification of P concentrations in groundwater systems immensely important. Machine learning models have been employed to quantify the concentrations of various contaminants in groundwater, but to our best knowledge have never been used for the quantification of groundwater P. The goal of this research was to use a boosted regression tree framework to produce one of the first machine learning model of P variability in groundwater, with the High Plains aquifer serving as the study area. Boosted regression tree models that could explain and predict the statistical variance of P throughout the aquifer (under standard conditions) were developed, but with low predictive capacity. Observed P values from testing dataset compared to predicted values had a R2 of 0.7265, though this value could be skewed by better correlation between the actual and predicted at lower concentrations of P (<u><</u> 0.05 mg/L). Lack of sufficient data and the raster file extraction method employed were identified as possible reasons for the low predictive capacity, and could be improved by more data. The research provides important variable correlation data that can potentially be incorporated into future studies that aim to further understand P dynamics in groundwater.
Geophysical methods for mapping aquifers: A case study at the UM field station
Year: Authors: Wodajo L., Buskes E., Mamud M.L., Hickey C.
Complex hydrogeological formations and high spatial variability due to various hydrogeological processes make groundwater exploration challenging. Geophysical methods can address the methodological need for groundwater mapping and identifying optimal locations for extraction. The University of Mississippi Field Station is a 740-acre lot owned by the University of Mississippi for ecological research. The University's Geology and Geological Engineering Department proposed a location to place a groundwater extraction well in the field station. This study is conducted to investigate if the proposed location is optimal for groundwater extraction and to test the capabilities of two ground-based electrical resistivity geophysical methods, electrical resistivity tomography (ERT) and vertical electrical sounding (VES), in mapping aquifers and providing actionable information. New and available well logs are used to identify the different soil layers and calibrate the geophysical results. The geophysical results and the well logs provided information that could be used to identify the location of the aquifer at that site. ERT results provided spatial images of the electrical resistivity distribution of the subsurface that filled in the information gap between adjacent boreholes. This study showed that the aquifer at the site changes from confined to unconfined over short distances. The original proposed well location is not optimal for groundwater extraction, and more suitable locations for well drilling are identified. This research is sponsored by the Mississippi Water Security Research Initiative Seed Grant provided by the Robert M. Hearin Support Foundation. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the sponsor's views.
Modeling of wave induced embankment erosion and recession
Year: Authors: Ozeren Y., Rossell W., Wren D.
Irrigation reservoir embankments are subjected to rapid erosion and retreat due to wind-generated waves. Accurate prediction of embankment recession rate is necessary to correctly assess the level of impairment and identify protection strategies. In this study, two different models were used to predict the embankment recession rates for soil embankments subjected to waves: XBeach, an open-source coastal modeling software developed by Deltares, and the USDA-ARS Bank-Stability and Toe-Erosion model (BSTEM). A one-dimensional numerical wave tank was created using the XBeach and simulations were carried out in order to understand the mechanisms involved during the recession of earthen embankments and provide accurate prediction methods. The simulation results were compared with the laboratory experiments in a wave tank at the USDA-ARS National Sedimentation Laboratory. BSTEM simulations were carried out at both laboratory and field scales. The results showed that the XBeach model reasonably predicted the embankment recession, except during the initial formation of the beach slope. A comparison of these simulations will be presented.
Assessing field-scale Lower Mississippi Alluvial Plain crop water use with remotely sensed data and cloud computing
Year: Authors: Yang Y., Anderson M., Hain C.
The Lower Mississippi Alluvial Plain (LMAP) is one of the most productive regions in the United States, with large area of corn, soybean, rice and cotton planted. Associated with the intensified agricultural activities, this region has been experiencing a rapid decrease of ground water table that can threaten the sustainability of water supply and this condition may get worse under the changing climate. To solve the issue with groundwater depletion, it is critical to understand how the irrigation water is currently used by various crop types and different fields. Evapotranspiration (ET) represents the land surface water use and is a key parameter in the hydrological cycle. Field-scale ET retrieved from satellite data has been heavily evaluated by comparing with flux tower observations and proved to be efficient for agriculture management impact study, crop water use accounting, crop yield estimation, and irrigation scheduling. This work will assess ET in the LMAP region at field scale to provide critical local water use information for improved agriculture and water resource management. The energy balance model based on remotely sensed data will be used to estimate field-scale daily ET with key inputs from Landsat 8 and Landsat 9 from NASA. Through the OpenET project, with six widely used ET models implemented into Google Earth Engine to leverage the strong cloud computational power, field-scale large area ET over the LMAP region will be estimated. This work will help to address the challenge of water resource sustainability under the changing climate over the environmental vulnerable area.
Improving soil health with cover cropping, manure application, and crop rotation
Year: Authors: Kovvuri N.R., Feng G., Bi G., Adeli A., Jenkins J.
Soil health can be evaluated by the ability of the soil to absorb, store and discharge water while preventing water erosion. The common management practices to restore soil health sustainably is the integration of different cover crops, manure application, and crop rotation. Studies have shown that the cultivation of different cover species for a long period of time has the potential to improve soil structure, aiding in infiltration and porosity, resulting in improved soil health by increasing soil organic carbon and total nitrogen content. An ongoing field study started in the year 2019 at the R.R Foil Plant Science Research Center with seven cover crop treatments to understand the influence of different cover crops like elbon rye, daikon radish, Austrian winter field peas, and a mixture of these cover crops on soil health, water quality that can impact crop production and climate change and resilience. This field has been incorporated with two tons of poultry litter every year, which is potentially known to improve the soil structure and several soil properties. Several soil health indicators can be chosen for assessing soil health. For this study, core soil sampling was done at the depths of 0-5 and 5-10 cm, and loose soil sampling was done at the depths of 0-5, and 5-10, 10-15 cm, and 15-30 cm after the termination of cover crops. We measured soil physical and hydraulic health indicators such as water stable aggregates, bulk density, available water content, and saturated hydraulic conductivity at the USDA-ARS Soil Physics and Hydrology Laboratory, Starkville. Soil chemical health indicators were also measured, such as total carbon, total nitrogen, pH, K, P, Mn, and organic matter. All those indicators have been used to calculate the overall soil health score. The Principal component analysis (PCA) was applied to perform the soil health assessment. The results indicated that the integration of cover crops improved soil properties as compared to no cover crop treatment. There was a significant difference between the cropping systems and the depth of the soil, indicating that the cotton crop responded well to the cover crop treatments than the corn crop, and the topsoil (0-5 cm) was found to be healthier at p < 0.05. However, no significant differences have been observed within the cover crop treatments, and long-term studies are necessary to understand the influence of different cover crops on soil health.
Application of geospatial technologies in adaptive management assessments of sea level rise impacts on coastal infrastructure
Year: Authors: Grala K., Cartwright J.
Coastal infrastructure systems experience severe impacts due to high tide flooding, storm surge, and reoccurring extreme weather events. Geospatial technologies are commonly used to assess the severity of these impacts. However, the selection of custom-made geospatial tools that would allow decision-makers to produce rapid assessments of these impacts is limited. This is particularly true for tools supporting adaptive management decisions that must account for unknown factors when evaluating critical infrastructure systems such as roads, powerlines, and wastewater disposal sites. We used Geographic Information Systems to improve data analysis and assess current and future threats related to the projected sea level rise (SLR) scenarios. This presentation highlights the work of two geospatial efforts for the infrastructure assessments at both the regional and local scales. These efforts include a multistate vulnerability assessment of the SLR impacts on transportation infrastructure and a local-level analysis of on-site wastewater disposal systems. Methodologies for these projects are based on geospatial science and consider spatial relationships between the SLR layers and different segments of infrastructure systems. The results are disseminated via interactive web-based applications (maps and dashboards) to help identify the most vulnerable coastal communities. These efforts produced geospatial tools to automate assessments of the projected SLR scenarios and data extraction across multiple layers. Decision-makers can use the developed tools to augment their decision-making processes and find better adaptive management solutions to ensure that the coastal communities are more resilient to potential SLR impacts.
GeoVisualization and 3D geospatial technologies for coastal inundation
Year: Authors: Cartwright J., van der Zwaag J., Grala K.
The frequency of flooding events in coastal areas has been increasing for several decades. Current sea level rise projections for this century will make the extreme events of today the norm by 2100. As the frequency of these events increases so does the need for improved education and decision-making. Through the Geospatial Education and Outreach (GEO) Project, efforts have focused on the development of a suite of applications to simulate and visualize sea level rise. GeoCoast3D is an interactive web-based application that allows users to visualize inundation along the MS coast. Using routing analysis, users can visualize the impact of inundation on transportation and service areas for critical infrastructure. This provides them with an enhanced view of the dangers in relation to rising sea levels and hurricanes in coastal communities. The GeoLidar Viewer was created based on colorized LiDAR datasets combined with other layers, including 3D buildings, sea level rise extents, LiDAR-based elevation, and satellite imagery. These layers are displayed in a single interactive 3D scene that is publicly available online. Individual layers can be turned on and off to change the focus of the display to various landscape features. These efforts are being coupled with augmented and virtual reality for in situ 3D modeling of coastal flooding. GeoInundation uses detailed, realistic models generated from LiDAR data, satellite imagery, and site photos. GeoPanorama combines 360° panoramic photos with LiDAR data to create immersive, realistic virtual reality experiences. Both allow the user to simulate water surface height or select a predefined historical high water marker. GeoCoast AR (currently in beta development) allows users to increase and decrease simulated inundation levels on the actual landscape as they navigate the area through the camera on their mobile device.
Benthic macroinvertebrate assemblage responses to stressor gradients in Mississippi Alluvial Plain ecoregion streams
Year: Authors: Hicks M., Taylor J., Devilbiss S.
Large alluvial plain landscapes, such as the Mississippi Alluvial Plain (MAP) ecoregion, are some of the most agriculturally productive lands in the world but often have modified stream ecosystems due to cultivation history. This context requires consideration when establishing water quality management goals and expectations. We analyzed state water quality databases to demonstrate MAP streams are distinct from streams in other ecoregions of Mississippi. Streams in the MAP have elevated alkalinity, specific conductivity, and nutrients and lower macroinvertebrate diversity compared to streams in other ecoregions. Our results also suggest that water-quality between MAP-confined drainages and MAP-Mississippi Valley Loess Plain drainages differs substantially and should be considered when setting water quality goals and expectations for streams in the MAP. We also explored whether the use of threshold indicator taxa analysis (TITAN) could effectively be used to assess the biological health of the study drainages. Our results from TITAN suggest that macroinvertebrate taxa responses in MAP streams occurred at higher concentrations of alkalinity, total organic carbon, and total phosphorus in comparison to other ecoregions in Mississippi. In addition, many indicator taxa identified by TITAN were only responsive in MAP streams suggesting that biological responses in the MAP are driven by unique taxa that respond to water-quality gradients at higher levels as compared to other ecoregions. We establish the potential for a taxa-based approach to provide a tool for guiding and monitoring success of nutrient reduction efforts in MAP watersheds and other alluvial plain agroecosystems where local and regional taxa pools are less diverse and may not support full recovery of ecological assemblages.
Redefining biological tolerance in the context of highly modified agricultural watersheds
Year: Authors: DeVilbiss S., Taylor J., Hicks M.
Agricultural intensification has caused substantial alterations to aquatic ecosystems including habitat degradation and eutrophication. Establishing water quality goals to guide management efforts for reducing agricultural impacts to surface waters relies on developing stressor-response relationships between biological assemblages and water quality stressors. Traditional approaches for developing stressor-response relationships depend on historical tolerance values that quantify the ability of different biological taxa to survive in degraded conditions. However, many tolerance values for macroinvertebrates, which are perhaps the most widely used biological assemblage for monitoring and management purposes, were developed in less altered regions and may not reflect the unique ecology of highly modified agroecosystems. Thus, developing effective management and monitoring tools for highly modified regions may require re-examining how we define and characterize biological tolerance. Using data from the Mississippi Alluvial Plain (MAP), an intensely cultivated ecoregion in Mississippi, we outline a method for identifying regionally-specific groups of tolerant and intolerant taxa for individual water quality stressors like nitrogen and phosphorus, eliminating the need to rely on historical tolerance values. We further demonstrate how modeling approaches can be applied to these regionally-specific taxa groups for water quality monitoring and establishing reasonable expectations for biological improvements following the implementation of best management practices. Lastly, we apply this novel approach to DNA-based bacterial assemblage data as an example of how multi-assemblage responses can be combined to better constrain water quality goals.
Physical drivers of streamflow and drying across a physiographic gradient in the Southeastern US
Year: Authors: Peterson D., Jones C.N., Wolford M., Zarek K., Speir S.
Non-perennial streams (i.e., streams that dry regularly) comprise over 50% of the global river network and play an important role in influencing the physical, chemical, and biological characteristics of downstream waters. In the Southeastern United States, non-perennial streams occur in the headwaters of river networks, and their unique patterns of drying have not been well-characterized. In these systems, heterogeneity of watershed physical features, including stream slope, subsurface architecture, and preferential flowpaths, play a key role in spatial and temporal variation in streamflow and drying. Our goal is to develop a predictive understanding of spatiotemporal patterns of stream drying across watersheds representative of three distinct physiographic regions in Alabama: the Coastal Plain, Piedmont, and Appalachian Plateau. We characterized longitudinal network connectivity over an annual drying cycle with empirical water presence data collected using Stream Temperature Intermittency and Conductivity (STIC) loggers dispersed throughout the watersheds. We also characterized watershed structural features, including elevation, slope, soil depth, and valley shape, using publicly available data. Combining these data sources allowed us to compare spatial and temporal patterns of network drying to identify potential drivers. Our initial results suggest that each physiographic region may have a unique drying regime, and that drying occurs hierarchically within watersheds. Our work provides insight into the drivers of stream drying in the Southeast, better informing our understanding of the structure and function of these important stream networks.
Next-generation hydraulic modeling tools: Advancing the state of practice for hydraulic engineers, improving the understanding of complex interactions between river environments and transportation assets
Year: Authors: Westerfield R.
The Mississippi Department of Transportation (MDOT) bridge hydraulic design has evolved significantly over the past ten years by using the emerging two-dimensional (2D) hydraulic modeling software. Two-dimensional (2D) hydraulic modeling software, graphical interfaces, and supporting resources are available that can be applied to infrastructure design to improve understanding of the complex interactions between river or coastal environments and transportation assets. Recent advances in computer hardware, modeling software, Geographic Information Systems, and survey practices have made 2D modeling very efficient, intuitive, and accessible to engineers and designers. This emerging technology provides the following benefits: <ul><li>Improved Quality and Resiliency. 2D modeling results provide more accurate representations of flow conditions, including depths and velocities. Improved project quality may often be realized by using 2D modeling results to inform the location and size of structures, determine depths of bridge foundations, and analyze environmental impacts.</li> <li>Enhanced Collaboration. 3D graphical visualizations derived from 2D modeling offer better tools for communicating the often complex interaction between waterways, the transportation infrastructure, and the surrounding environment. </li> <li>Streamlined Delivery. Improved collaboration can help streamline project development, including environmental, regulatory, and engineering activities. </li></ul> Rachel currently serves as lead Drainage Engineer for Gresham Smith across the Transportation Market. She started her career at the Mississippi Dept. of Transportation in Bridge Division in 2003 and served as the State Hydraulic Engineer for seven years before moving into the private sector. Rachel has completed hydraulic design in Mississippi, Georgia, Tennessee, and Kentucky and continues to sharpen her knowledge and experience as the hydraulic engineering field is continually expanding and changing. She has experience in bridge hydraulic analysis and design, federal regulatory compliance, bridge hydraulic modeling, risk and impact assessments, stream stability, and scour analysis. <br /><br /> Education:<br /> Bachelor of Science, Biological Engineering, Mississippi State University<br /><br /> Registrations:<br /> Licensed Professional Engineer: MS, TN, GA, KY, LA<br /><br /> Certifications:<br /> ASFPM Certified Flood Plain Manager (CFM)<br /><br /> Gresham Smith is an architecture, engineering and design practice that provides creative solutions while genuinely caring for each other, our clients and our communities.
Initial assessment of managed aquifer recharge feasibility at the groundwater transfer and injection pilot project, Shellmound, Mississippi
Year: Authors: O'Reilly A., Wren D., Locke M., Rossell W., Mirecki J.
To assess the potential for managed aquifer recharge to mitigate declining groundwater levels in the Mississippi River Valley alluvial aquifer (MRVAA) and support irrigated agriculture in the Delta, the U.S. Department of Agriculture, Agricultural Research Service, National Sedimentation Laboratory, in partnership with local stakeholders and U.S. Army Corps of Engineers, is conducting the Groundwater Transfer and Injection Pilot (GTIP) project. The system consists of one extraction well, a 1.8-mile pipeline, and two injection wells, with a design capacity of 1,500 gpm. Groundwater is filtered by passing through sands adjacent to the Tallahatchie River and subsequently is extracted, transferred, and then injected into a depleted section the MRVAA. Data collection at 17 observation wells and the river includes continuous groundwater level and monthly water quality samples. Prior to operation, observations indicate ambient groundwater was less mineralized at the extraction site than the injection site but both exhibited suboxic iron-reducing redox conditions, and groundwater levels responded to seasonal weather cycles, irrigation withdrawals, and river stage. Operation began in 2021, and two injection tests have been conducted for durations of 89 and 204 days, yielding total injected volumes of 550 and 575 ac-ft, respectively. During the first test the injection rate averaged 730 gpm/well with both wells running simultaneously, causing 6.7-ft increase in groundwater level at the injection site and 4.7-ft decrease at the extraction site. During the second test, both wells were run simultaneously for the first 13 weeks at a rate averaging 570 gpm/well, but due to declining capacity of the extraction well, injection wells were thereafter operated individually on a weekly schedule at 600 gpm. By the end of the second test, impacts were observed 1 mile from the injection wells where the groundwater level increased 0.3 ft. During both tests, differences in water chemistry between the river and extraction well indicate increased mineralization due to rock-water interactions and biogeochemical processes during riverbank filtration, whereas relatively small changes in water chemistry occurred in the MRVAA at the injection site. Clogging of the injection wells by iron bacteria terminated the first test; treatment with a dilute oxalic acid solution returned both wells to their prior capacities. No effects of clogging were observed during the second test. However, the extraction well experienced increasing drawdown over time, which was likely related to low river stage and possibly further impaired by formation of an adjacent sinkhole. Findings from the GTIP project demonstrate its technical feasibility in the Delta and the importance of considering the unique hydrogeology of the region, maintaining similar water chemistry between the injected water and ambient groundwater, and coordinating operating schedule with river stage and riverbank filtration capacity.
Geochemistry of the Mississippi River Valley Alluvial Aquifer and preliminary analysis of impacts from the groundwater transfer and injection pilot project in Shellmound, Mississippi
Year: Authors: O'Reilly A., Yarbrough L.
The Mississippi embayment aquifer system comprises six regional aquifers. The shallowest aquifer is the Mississippi River Valley alluvial aquifer (MRVAA), which is intensively pumped for agricultural irrigation in the Delta region of Mississippi. With long-term decreases in the water level and continuing groundwater withdrawals, long-term groundwater availability from the MRVAA is a concern. Thus, the U.S. Department of Agriculture, Agricultural Research Service, National Sedimentation Laboratory is implementing the Groundwater Transfer and Injection Pilot (GTIP) project to determine the effectiveness of using managed aquifer recharge (MAR) to support groundwater availability from the MRVAA in the Delta. The MAR technology being tested by the GTIP project uses source water obtained by riverbank filtration from the Tallahatchie River and transfers and injects the water into the MRVAA where water levels have declined. However, by inducing the infiltration of river water into the aquifer, the quality of the source water and groundwater must be examined. The water quality of the MRVAA in other locations has been previously reported, but these results do not reflect the water quality after transfer and injection. Thus, a new collection of chemical analysis is needed to determine the potential impact of groundwater transfer and injection on water quality. The water quality samples were collected at 17 observation wells, one extraction well, two injection wells, discharge pipe for injection well backflush water, three sites in Lake Henry and the river. For each collection site, values for pH, specific conductivity, temperature, and dissolved oxygen were also measured. One sampling event was conducted prior to operation in March 2021, and monthly sampling events were continued during two operational periods—April to July 2021 and February to August 2022—for a total of 13 sampling events. In 1978, the water quality of the MRVAA was analyzed in the Delta. These results showed that the groundwater had the following characteristics: a hard calcium bicarbonate type, dissolved iron concentration greater than 3 mg/L, elevated concentrations of manganese, and a range of dissolved solids concentrations (153-751 mg/L). Thus far, our sampling results have demonstrated the groundwater to be of calcium bicarbonate type in the MRVAA, with total iron and manganese concentrations exceeding 1.5 and 0.2 mg/L, respectively. Generally, the higher levels of iron in the MRVAA have occurred at observation wells west of the Tallahatchie River and northeast of Lake Henry. The total dissolved solids range from 86-622 mg/L. Variation of this range is presented in the observation wells. However, the lowest total dissolved solids are more prevalently identified at the Tallahatchie River and in Lake Henry at the sampling site where backflush water is discharged. Further work contributes to the understanding of natural and MAR induced evolution of water quality.
Control of terrestrial alligatorweed in Mississippi
Year: Authors: Turnage G., Thompson W.
Alligatorweed (Alternanthera philoxeroides) is the most widespread aquatic weed in Mississippi. Alligatorweed is capable of growing in aquatic, wetland, and terrestrial sites and switches growth form from a rhizomatous mat forming plant (aquatic) to a prostrate growth form with tap roots (terrestrial) which allows it to survive stressors such as drawdown or drought. Much is known regarding the impacts and control of alligatorweed in aquatic sites, however, less is known regarding control of alligatorweed in terrestrial sites. Muscadine Farms Wildlife Management Area (WMA) is a series of 90 ponds (each 6.1-8.1 hectares in size) that covers approximately 809 ha in the Mississippi flyway in western Mississippi; the WMA is primarily managed for waterfowl habitat. The terrestrial form of alligatorweed has infested many ponds in the WMA and displaced desirable vegetation utilized as waterfowl forage. In 2022, an herbicide trial was conducted and repeated two weeks later to assess the reduction of alligatorweed at Muscadine Farms by herbicides utilized for operational control of alligatorweed as well as newer herbicides labeled for use in aquatics in the last two decades. Herbicides were applied to 83.6 m-2 (9.1 by 9.1 m) plots at Muscadine Farms. High and low rates of imazapyr (8.2 and 4.1 kg a.e. ha-1), bispyribac-sodium (0.11 and 0.055 kg a.i. ha-1), topramezone (11.4 and 5.7 kg a.e. ha-1), florpyrauxifen-benzyl (0.02 and 0.01 kg a.i. ha-1), and fluridone (10.9 and 5.4 kg a.i./ha-1) were tested as stand-alone foliar herbicide treatments. Glyphosate (11.0 kg a.i. ha-1), triclopyr (11.7 kg a.e. ha-1), metsulfuron-methyl (0.036 kg a.i. ha-1), and two-way tank mixes of the three were also tested as foliar treatments. All herbicide applications included a 0.5% v:v MSO surfactant and were applied at a 467.7 L ha-1 (50 gal ac-1) diluent rate. Each treatment was replicated four times. This is the first report of alligatorweed control by bispyribac-sodium (88 to 94% reduction), topramezone (76% reduction), florpyrauxifen-benzyl (85% reduction), or fluridone (76 to 93% reduction) suggesting that these herbicides may provide another alligatorweed control option for resource managers. A follow up trial found that disking or mowing alone provided 99 and 72% reduction (respectively) of alligatorweed biomass suggesting these may be suitable non-chemical control techniques for alligatorweed in terrestrial systems.
Chemical and biological control of alligator weed (Alternanthera philoxeroides), an invasive aquatic plant in Mississippi
Year: Authors: Schmid S., Turnage G., Ervin G.
Alligator weed (Alternanthera philoxeroides) was first introduced into the United States in 1897 from Argentina and has since become a widespread invasive species that threatens global water resources. In infested systems, alligator weed can form dense mats that displace native plants and interfere with natural ecosystem processes. Alligator weed has been a persistent problem in Mississippi and is the most commonly surveyed aquatic plant in the state. Foliar herbicide applications are commonplace for reducing alligator weed biomass, and although the plant has shown high susceptibility to these methods, its extensive stolon network facilitates robust and rapid regrowth. However, many herbicides labeled for use in aquatics can be applied directly to the water column as a submersed injection; this method allows herbicides to be taken up by roots rather than foliage and may provide more efficacious biomass reduction than foliar herbicide applications. For this study, we compared the efficacy of five herbicides (bispyribac-sodium, fluridone, imazamox, penoxsulam, and topramezone) applied as submersed injections at maximum and half-maximum label rates to reduce alligator weed grown in outdoor and greenhouse mesocosms. Our results identify multiple highly successful control methods to be tested on field populations of alligator weed and tested as part of an integrated control strategy. Aside from chemical control, the alligator weed flea beetle (Agasicles hygrophila) has been used as a biocontrol agent in the U.S. but it is very intolerant to cold climates. Therefore, a secondary biocontrol agent, the alligator weed thrips (Amynothrips andersoni), may be of use as part of an integrated control strategy as it is more cold tolerant. However, research on the thrips is diminutive compared to the flea beetle. Our future work will assess these chemical control strategies integrated with alligator weed thrips with a goal of developing an effective integrated pest management plan for alligator weed in Mississippi.
Legislation and status of aquatic noxious weeds in the Southeastern U.S.
Year: Authors: Kappaui J., Turnage G.
Aquatic invasive plants (ANS) can negatively affect water chemistry, disrupt ecological processes, lower biodiversity, and impact human uses of water resources. Because of their ability to rapidly colonize new habitat, many states and the federal government have placed invasive aquatic plants on noxious weed lists with the aim of reducing their spread. The states of the southeastern U.S. (TX, LA, MS, AL, FL, GA, SC, TN, AR, and KY) have dozens of invasive aquatic plants but only a few are listed as noxious weeds. Many states have varying definitions and classes of noxious weeds thus complicating efforts to control the spread of these species across state lines. This project aims to describe and combine the current legislation regarding noxious weeds in each state of the southeastern U.S. into a factsheet in an effort to provide resource managers and stakeholders a common resource to help slow the spread of these problematic species.
Scratching the surface of phosphorus dynamics in the Mississippi Delta
Year: Authors: Witthaus L., Pawlowski E., Locke M., Stevens E., Chatterjee A.
Colloquially, Mississippi Delta soils are known to be high in phosphorus. While soil phosphorus levels do not reach those of the Upper Midwest or areas applying animal manure, Delta soils retain a high level of phosphorus without continual application. However, there are limited publications conveying soil and sediment nutrient levels in this region. Understanding baseline soil nutrient levels, as well as nutrient dynamics, can improve simulations of nutrient transport in models and provide valuable information for watershed water quality management. This presentation will showcase results from a study evaluating properties of soils in both agricultural and forested areas within four different soil series common in the MS Delta: Dundee, Forestdale, Alligator, and Sharkey. We found that Mehlich-3 phosphorus (P) levels were similar across Alligator, Dundee and Sharkey soils in both land uses, but they differed in Forestdale soils. Soils in forested areas exhibited higher total carbon (C), and nitrogen (N) concentrations (p<0.01) compared to soils in cropped areas. Mehlich-3 iron had a positive correlation with Mehlich-3 P in three of the soil series in cropland, but the relationship was negative for natural soils. A suite of other variables was measured and relationships between these characteristics will be explored in this presentation. In addition, we will demonstrate potential uses for such a database through a modeling example.
Cyanobacteria blooms, nutrient limitation, and sensitivity in two Mississippi Delta lakes
Year: Authors: Lizotte R.
Intensive row-crop agriculture in the Mississippi Delta has increased eutrophication and cyanobacteria blooms in freshwater systems in western Mississippi. Two study lakes, Beasley Lake and Roundaway Lake, are shallow riverine lakes influenced by agricultural activity typically found in the Mississippi Delta. During 2018, both lakes were monitored for nutrients and cyanobacteria (measured as phycocyanin concentration). Both monitored lakes indicated eutrophic to hypereutrophic conditions. Total nitrogen (TN) ranged from 0.7 to 2.1 mg/L (average: 1.3 mg/L) and 1.1 to 3.6 mg/L (average: 1.8 mg/L) in Beasley and Roundaway, respectively. Total phosphorus (TP) ranged from 0.05 to 0.49 mg/L (average: 0.18 mg/L) and 0.08 to 0.46 mg/L (average: 0.22 mg/L) in Beasley and Roundaway, respectively. Cyanobacteria blooms ranged from 5 (March) to 112 (June) µg phycocyanin/L and 4 (April) to 210 (June) µg phycocyanin/L in Beasley and Roundaway, respectively. Cyanobacteria nutrient limitation was assessed during summer and fall (June-November 2018). Cyanobacteria nutrient sensitivity was measured in October 2018 when ambient nutrient concentrations were lowest to ascertain nutrient concentrations eliciting cyanobacteria blooms. Results indicate that summer and fall cyanobacteria biomass were primarily nitrogen + phosphorus co-limited in both lakes. Nutrient sensitivities indicated that lake cyanobacteria blooms occurred when: NO3-N > 0.15 to 0.28 mg/L; TN > 0.38 to 0.48 mg/L; PO4-3 > 0.03 to 0.06 mg/L; and TP > 0.04 to 0.07 mg/L. Regression analysis showed that summer to fall increased lake cyanobacteria nitrogen + phosphorus co-limitation responses occurred with elevated PO4-3 and decreased NH4-N during summer and fall (adjusted R2 0.42, p = 0.036, N = 12). Monitored Roundaway Lake summer to fall cyanobacteria biomass increased with elevated TN and decreased NO3-N (adjusted R2 0.82, p < 0.001, N = 14). Monitored Beasley Lake summer to fall cyanobacteria biomass increased with elevated NH4-N and decreased NO3-N (adjusted R2 0.45, p = 0.021, N = 13). This study provides insight and understanding of necessary nutrient controls to better manage and mitigate cyanobacteria blooms and improve water quality in Mississippi Delta agricultural lake watersheds.
Municipal wastewater systems management and maintenance
Year: Authors: Ford G., Rokooei S., Hatami A.
A common treatment in municipal wastewater systems in the United States is aeration. Aeration promotes growth of microbes which feed on organic waste, easily removed from wastewater through flocculation. Aerators are often the most expensive treatment component in municipal systems from an electrical cost standpoint. They can also be challenging to maintain. Blower CFM, manifold pressure, leaking pipes, gearbox malfunction and motor failures are a few of the operation issues posed by aerators. If the aerators are not providing enough oxygen to the wastewater, the treatment system effectiveness may be severely impaired. To minimize maintenance and operating costs and to ensure system effectiveness, holistic maintenance and treatment plans must be considered. This discussion will examine aeration at a local wastewater treatment plant in northeastern Mississippi and recent issues experienced with Aerator gearbox failures. The causes of these failures and the chosen solution will be presented.
Enhancing knowledge and facilitating adoption of irrigation water management practices through education
Year: Authors: Russell D., Gholson D.
Prior research has shown that implementing irrigation water management practices can reduce total water applied while maintaining or improving crop yield and profitability. However, to effectively utilize these proven practices, a complex understanding of the soil-water-crop dynamics and the irrigation scheduling tools and technologies is required. Modeled after the award-winning Master Irrigator Program from the North Plains Groundwater Conservation District in Dumas, Texas, the Mississippi Master Irrigator Program is designed to educate producers on soil health, agronomics, irrigation scheduling, irrigation systems and equipment maintenance, the economics of irrigated agriculture, and policy and management. This course will be delivered through a hybrid approach consisting of online modules and in-person training and demonstration activities. The course is also designed to facilitate peer-to-peer engagement and to inform producers of the numerous resources available to them. Instructors for the online modules and in-person training events will be MSU Extension Specialists, as well as other individuals/entities with specialized experience in each of the program topics. Once the online modules are complete, the online portion of the course will be available for registration. Participants will be required to complete prerequisite modules to be eligible for the in-person training. This presentation will focus on the development and implantation of a new Extension education program designed to equip producers with the knowledge they need to make the right irrigation water management decisions that improve soil health, water use efficiency and conservation, and profitability on their operation.
Multi-level partnerships and collaborations support the Florida well owner network
Year: Authors: Albertin A., Zhuang Y.
The Florida Well Owner Network (FWON) is a drinking water quality and septic system educational program that was developed for Florida decentralized water users. Our goals are to educate residents about well water quality and best management practices to ensure well and groundwater protection, facilitate water testing, and provide disaster relief assistance after major storms. To successfully achieve these goals at state and local levels, FWON has brought in multi-level partnerships and collaborations. These include internal and external state specialists, county extension agents, local health departments, water management districts, and state-certified water quality testing labs. Extension specialists provide research on drinking water contamination and treatment. County extension agents organize workshops through their established networks and help teach residents. Local health departments and water management districts provide local well water information and funding for well water testing. State-certified water testing labs enable drinking water testing through standardized methods. Since 2017, 1,289 residents have been educated about water quality and septic system maintenance through FWON and 451 people have had their well water tested for bacterial contamination. Due to COVID-19, we switched from in-person workshops to webinars, reaching approximately 500 well users in 2021 and early 2022. Our efforts are currently focused on providing workshops both in-person and online, and as FWON grows major challenges include organizing larger sampling events and funding to process analyses.
Scaling down GRACE data for smaller regions: utilizing artificial neural networks and climate data for enhanced hydrological predictions in the state of Mississippi
Year: Authors: Awawdeh A.R., Yasarer H., Pulla S., Kumar M.
The importance of having accurate and high-resolution hydrological data has risen with recent climate change and ongoing dependence on underground water. The launch of the Gravity Recovery and Climate Experiment (GRACE) in 2002 made it possible to acquire such data, enabling researchers to extract information on terrestrial water storage, ice loss, and sea-level change at a temporal resolution of one month. However, this data is not adequate for smaller regions due to the coarseness of the GRACE data grids, which have a resolution of 56 km by 56 km. This study aims to investigate the effectiveness of using Feedforward Artificial Neural Networks (ANNs) with the backpropagation error algorithm to scale down GRACE data for the State of Mississippi to smaller grids of 4 km by 4 km that can be used in smaller regions. This process utilized Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) and TerraClimate databases. CHIRPS provides high-resolution rainfall data, while TerraClimate provides a dataset of monthly climate and climatic water balance for global terrestrial surfaces. A script in Python programming language executed via Jupyter Notebook was developed to download all the necessary data and develop the ANN model. Initial results indicated that the ANN approach performed well with an R2 of 0.93, and the developed models can be utilized to predict equivalent water thickness with high accuracy in the Mississippi region. The current effort is focusing on validating the model by comparing the downscaled GRACE data against well-water data in the Mississippi Delta area and assessing the model's ability to identify drought activities that occurred within the study period from 2002 to 2020.
Negative results matter—complications of the groundwater transfer and injection pilot project
Year: Authors: Rossell W., O'Reilly A., Wren D.
In an effort to address the impact on groundwater resources caused by widespread pumping for irrigation in the Mississippi Delta region, the Groundwater Transfer and Injection Pilot (GTIP) project was undertaken by the U.S. Department of Agriculture, Agricultural Research Service, National Sedimentation Laboratory to assess the potential benefits of such a managed aquifer recharge practice. The GTIP project transfers source water obtained by riverbank filtration to an area of declining groundwater levels and recharges the aquifer using two injection wells. The facility has completed two pumping tests, a 3-month duration in 2021 and a 6-month duration in 2022. Throughout both tests, the inactive period between, and the inactive period following the 2022 test, groundwater level and groundwater quality data has been routinely recorded to evaluate the impacts of the project on the local environment. However, complicated circumstances and problematic events have also been encountered beyond those which were originally anticipated. This presentation will introduce some of these issues to the greater community and provide some current working hypotheses of causative factors. In particular, this presentation will briefly present the following topics: sinkhole formation on the GTIP project site, difficulties presented by the high iron concentration in the region's groundwater, the problem of injection well-screen clogging by iron-related bacteria, and unexpected groundwater drawdown during riverbank filtration. While the cause of many of these events is still under investigation and others may have been unavoidable, the benefit of presenting these negative results from the GTIP project is to better focus and expedite future research, leading to improved design criteria and more efficient operation and maintenance activities.
Discussion of preliminary results from use of machine learning for downscaling satellite-based soil moisture data for groundwater management
Year: Authors: Ellepola A., Yarbrough L., Ghaffari Z., Easson G., Yasarer H.
Satellite imagery has become an increasingly valuable tool for watershed management. Remote sensing systems such as multispectral and radar imaging can provide detailed information about soil moisture levels, vegetation cover, and topography. These data can be used to identify areas of high soil moisture, monitor changes in soil moisture over time, and assess the impact of human activities on watersheds. A commonly used system in orbit for monitoring soil moisture is the Soil Moisture Active Passive Mission (SMAP). For SMAP, and all spaceborne systems, one of the major limitations for users to implement satellite-based data is the extreme coarseness of the pixel (~9 km). This talk presents an overview of a machine learning technique that is currently being used in soil moisture monitoring and watershed management in north Mississippi.
MSU Extension Service's SipSafe Program
Year: Authors: Gann L.
Protecting children from lead exposure plays a critical role in ensuring they develop into healthy adults. Children under the age of 6 have shown slowed growth, learning disabilities and other physical and mental impairments after prolonged exposure to environmental lead. The SipSafe Program seeks to limit children's exposure to lead via drinking water by screening water in qualifying schools and childcare facilities across Mississippi, as well as offering remediation assistance and educational materials on the dangers of lead. Mississippi State Extension Service receives funding for the SipSafe Program via the EPA WIIN Grant and has implemented their 3Ts model. With assistance from Mississippi State Department of Health, Mississippi Department of Education, Mississippi State Chemical Laboratory and other cooperating partners, SipSafe has developed into a program that: <ul><li>Trains directors and staff at participating facilities how to protect their children from lead exposure.</li> <li>Tests drinking water in participating facilities for lead and its sources.</li> <li>Takes action to help facilities reduce the amount of lead in their drinking water and further raise state-wide awareness of lead exposure in children.</li></ul> Utilizing public water quality data and elevated blood lead level data, SipSafe has identified 14 counties in Mississippi in which to focus its initial screening activities. It is anticipated that data collected from these counties will be beneficial in future school and childcare drinking water screening efforts. For more information on SipSafe, visit <a href="https://extension.msstate.edu/sipsafe">extension.msstate.edu/sipsafe</a>
University of Mississippi Lead in Drinking Water Project
Year: Authors: Otts S., Willett K.
Childhood lead poisoning is a challenging social issue that requires the coordination of health, housing, and environmental law and policy. Little is known about the contribution of lead pipes and water treatment to lead poisoning in Mississippi. The University of Mississippi Lead in Drinking Water Project (UM Lead Project) launched in 2017 and is headed by an interdisciplinary team of researchers from the University of Mississippi (Stephanie Otts, J.D. and Dr. Kristie Willett) and the Southern Rural Development Center (Dr. John Green). The team takes a community-engaged, research-based approach to address lead in water-related health gaps in the state. To date, the Team has organized almost twenty lead education and sampling events, tested drinking water for more than 300 families, presented annually at the Mississippi Water Resources Conference, taught an Honors College Experiential Course, established a referral program with the Mississippi State Department of Health (MSDH), partnered with Mississippi State Extension's SipSafe program to sample water at childcare facilities for lead, and published two academic journal articles. This presentation will provide an overview of the team's work in 2022, including the results of a statewide lead forum hosted in Jackson, MS in October 2022.
Inland flooding impacts rural drinking water resources along the Gulf Coast
Year: Authors: Jones C.N., Hayes W., Peterson D., Terry L., Barrett J.
Along the Gulf Coast, private drinking water wells play an important role in delivering water to rural communities. Yet, these systems also present a public health concern due to inconsistencies in water quality testing, regular maintenance, and construction practices. Here, we focus on how hurricanes and the associated inland flooding impact private well systems using a combination of community science sampling campaigns and geospatial modeling. We conducted a community science sampling campaign after Hurricane Ida, and our results highlighted widespread bacterial contamination of private drinking water wells. To put these results into context, we used a combination of modeled well locations and remotely sensed inundation estimates to quantify the potential extent of flooding impacts on the well user community. Taken together, these initial results highlight widespread impacts of hurricanes on rural drinking water resources.
Technological improvements and upgrades to USGS monitoring network in Lower Mississippi River Basin, 2023
Year: Authors: Manning M.
The Mississippi River is one of the most extensively controlled rivers in the world. Man-made changes to the system have been documented as early as the 1700's. Today, flood-control levees are located along nearly 5,800 kilometers of the river's length; there are 29 lock-and-dam structures between Minneapolis, Minnesota and St. Louis, Missouri for navigational control; as well as many flow-diversion structures. All these alterations combined have created many positive water quality improvements, but has also created several unexpected negative impacts, including the reduction in the amount of transported sediment, in addition to the occurrence, duration, and extent of flooding. <br /><br /> The U.S. Geological Survey (USGS) collects hundreds of suspended sediment and water quality samples each year to support water resource managers in timely access of data. In conjunction with these efforts, the USGS also maintains a network of real-time continuous streamflow and water quality stations along the Mississippi River main stem, tributaries, and distributaries to support local, state, and federal agencies flood control and aquatic health decision-making. <br /><br /> In mid-2022, to continue to support these efforts, the USGS began working to develop a new generation sampler. This new sampler would incorporate all aspects of previous large river bag and point samplers into one unique sampler. Also, this new generation sampler can be deployed hosting sensors including turbidity, acoustic backscatter, and other parameters to record at depth. The USGS is also currently using panoptic live scope sonars to view samplers in real-time as they descend and ascend the rivers depths collecting suspended data. These and other data collected by the USGS provide invaluable information to many agencies who strive to sustain, safeguard, and monitor the Mississippi River during various hydrologic conditions.
Geophysical and acoustic approach for investigating internal soil pipe and gully erosion in agricultural field
Year: Authors: Samad M.A., Wodajo L.T., Rad P.B., Mamus M.L., Hickey C.J.
Soil erosion severely deteriorates agricultural fields by removing top fertile soil, increasing surface runoff, and reducing the soil's water-holding capacity. Increased loss of fertile agricultural land seriously threatens human habitat and livelihood, hampering agri-food production and impeding agricultural sustainability. Although soil erosion due to surficial processes (surface runoff, gully erosion, and channel erosion) is well-studied, contributions from subsurface processes such as internal soil pipes are difficult to study. As the diameter of a soil pipe increases over time, flute holes, sinkholes, and gullies develop and enhance soil erosion. Therefore, to implement early mitigation of soil erosion, it is essential to locate, map, and measure the extent of soil pipes in agricultural fields. The hidden and uncorrelated nature of soil pipes with surface features limits the applicability of remote sensing-based detection and mapping techniques. This study is conducted at a small area in Goodwin Creek Watershed, a site with established internal soil pipes, to test the applicability of two traditional geophysical methods, seismic refraction tomography (SRT), electrical resistivity tomography (ERT), and a new non-invasive acoustic method for mapping and tracking internal soil pipes. The geophysical and acoustic results were correlated with cone penetrologger (CPL) data to verify anomalies associated with internal soil pipes. The SRT indicated the location of internal soil pipe-affected zones with low seismic wave velocity anomalies. The ERT results indicated the location of soil pipe-affected zones with high resistivity anomalies. However, SRT and ERT lacked the resolution to identify individual soil pipes. The geophysical methods identified the fragipan layer that hinders the vertical flow, promotes the lateral flow of water, and accelerates the formation of soil pipes within the study area. The acoustic method identified five primary and eight secondary networks of soil pipes. Planting geophones at multiple locations, irrespective of source position, may provide the trajectory of soil pipes in the whole agricultural field. <br /><br /> This work was supported by the U.S. Department of Agriculture under Non-Assistance Cooperative Agreement 58-6060-6-009. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the U. S. Department of Agriculture.
Heterogeneous redox conditions in saturated soils: implications for ecological impact if oxbow wetlands are impounded for managed aquifer recharge
Year: Authors: Adele Bolaji B., Davidson G., Hossain M.R., Mamus M.L., Hickey C.J.
Over-drafting of regional aquifers such as the Mississippi Valley River alluvial aquifer (MRVA) has prompted a greater focus on methods of managed aquifer recharge. Previous work has demonstrated that oxbow lake-wetland systems on the floodplain of the Mississippi River can serve as significant sources of recharge, which could be enhanced by impounding water. Subsequent attention is needed on the potential ecological impacts of altering the natural hydroperiod. While it is typically assumed that flooding quickly results in anoxic soil conditions that diminish plant growth, some studies have reported increased in growth of wetland-adapted trees, such as bald cypress (Taxodium distichum), with increasing water level. A possible cause is a flux of oxygenated surface water through the root zone under greater vertical hydraulic gradients. Given the heterogeneous nature of forested wetland soils, caused in large part by buried decomposing tree remains, it is anticipated the soil redox response to rising water levels is highly variable, with the greatest increases corresponding to localized zones of higher permeability (preferential flow pathways). Preliminary data from redox and temperature probes deployed at two different elevations in the forested perimeter of Sky Lake, MS, are consistent with the hypothesis. Wet but aerated soils of some probes show rapid increases in redox potential following rainfall events, with smaller increases observed even if the soil is already saturated. Other probes indicate very little response, suggesting placement in zones of very low permeability. Under deeper water conditions, response to changes in water level and precipitation appear to be more complex.
Comparison of quality of stormwater runoff in a detention basin before and after the conversion to a bio-infiltration basin
Year: Authors: Benthota Pathiranage W., Surbeck C.
A stormwater detention basin is designed for the mitigation of possible hazards from stormwater runoff like flooding and erosion by temporally storing the excess runoff water and releasing it at a more controlled speed. The detention basin in front of the Robert C. Khayat Law Center, University of Mississippi, also has been designed for the same purpose. This detention basin was recently converted into a bio-infiltration basin with dry wells and cypress trees to further reduce stormwater runoff and pollution to receiving water bodies. Dry wells are used to increase the overall infiltration volume of the stormwater runoff. This can be specifically called a 'bio-infiltration basin' because the vegetation is used to help regulate the water content of the soil and intercept the rainwater. Five cypress trees have been planted in the detention basin. It was hypothesized that the quality of the water leaving the detention basin would be improved compared to the water entering it once it was converted to a bio-infiltration basin. The quality of the runoff water in the basin was evaluated in terms of total coliforms, E. coli, inorganic metals and suspended solid concentration based on the samples collected before and after the conversion into the bio-infiltration basin. Data collected since the basin conversion are not quantitatively enough to support or reject the project hypothesis. Still, the bio-infiltration basin is in its initial stage. This presentation reports on the test results that belong to the samples collected before and soon after the conversion to the bio-infiltration basin. It will take time for the plants' roots to grow and develop the tree canopy for a better infiltration performance. So, this is a continuous project that expects to collect more water quality data to investigate whether the infiltration mechanisms would really improve the quality of the stormwater runoff. It is recommended to test more water quality parameters that are influential to human health and aquatic ecosystems of the receiving water bodies.
Efficacy of best management practices in coastal watersheds
Year: Authors: Bhattarai S., Parajuli P.
Best management practices (BMPs) are implemented in coastal plains to reduce sediment and nutrient loss. This study assessed the effectiveness of BMPs in two coastal watersheds: Wolf River Watershed (WRW) and Jourdan River Watershed (JRW), using the Soil and Water Assessment Tool (SWAT) model. The coefficient of determination (R2) and Nash-Sutcliffe Efficiency (NSE) were used to evaluate the model performance. Effectiveness of impoundments and buffer were analyzed after successful model calibration-validation. Ponds reduced up to 75% Total Suspended Solids (TSS), 12% of Mineral Phosphorous (MinP), and wetlands reduced up to 75% of TSS, and 13% of MinP. The highest reduction of TSS and MinP was achieved by 30 m buffer in both watersheds. Furthermore, combined BMP reduced TSS by 30% and MinP by 52% in WRW, whereas TSS was reduced by 75% and MinP was reduced by 27% in JRW. Impoundments were more effective in reducing TSS and buffer were more effective in reducing MinP. This study demonstrated the effectiveness of BMPs in reducing TSS and MinP loss from coastal watersheds.
Predicting planted acreage and yield of soybean in wet, normal, and dry years in Mississippi State using APEX model
Year: Authors: Khanel P., Feng G., Huang Y., Han M.
Estimation of crop yield with approximate acreage is critical to crop production management decision support. This research aims to estimate the soybean yield and acreage during the wet, normal and dry years in Mississippi State using APEX (Agricultural Policy/Environmental eXtender) model which was developed to extend EPIC (Environmental Policy Integrated Climate model)'s capabilities of simulating management and land use impacts for whole farms and small watersheds (<a href="https://blackland.tamu.edu/models/apex" target="_blank">https://blackland.tamu.edu/models/apex</a>). APEX model uses data from the past to establish trends such as rainfall average, precipitation, soil, wind etc. to determine how the climate trend, management practices, and soil can affect the future of agriculture. APEX model is capable of long-term simulation of the fields ranging from small-scale to cross-country boundaries. For the research, APEX model was implemented for all soybean fields county by county across the entire state. The results from the research provide valuable information on the total area of soybean planted and the total yield of specific soybean fields in every county in Mississippi. The APEX model was implemented by utilizing various databases, including data of soil, weather, crop, field management, and spatial locations. The database provided reference for APEX model to determine which data to run for each simulation. The Gridded Soil Survey Geographic Soil Map (gSSURGO-30) (USDA Natural Resources Conservation Service (NRCS)) and the Gridded Cropland data layer (CDL-30 m) (USDA National Agricultural Statistics Service (NASS)) were downloaded and then uploaded into ArcGIS to apply Spatial Analyst tools in ArcGIS (ESRI, Redlands, CA) to overlay and clip the two data layers to fit into the area of interest. We then conducted georeferencing to get the geographic coordinates of the individual fields in the area of interest. In ArcGIS, we then used the SSURGO's table to link the field with type of soil in field. We then created the individual fields based on the soil, field size, and geographic coordinates using parameters such as type of soil found on the field, geographic coordinate, crop to be run, management file and weather station near to the field. Accordingly, weather data, such as wind, precipitation , daily/monthly temperature, and soil data, were converted into the required format for APEX model with Python programming. As a result, soil, and weather data files for all soybean fields in the entire state were created and the area and location of soybean fields was determined. Those data files were used by APEX model to simulate soybean yield for individual fields and the total yield for all fields in each county of the entire state. The output from APEX model was compared with the total area of soyabean field planted and yield data reported by the USDA NASS. The study will contribute to improving accuracy of those NASS reports for stakeholders in commercial community and researchers in scientific community.
Cover cropping and poultry litter improve soil physical and hydraulic properties in dryland conditions
Year: Authors: Kovvuri N.R., Feng G., Bi G., Tewole H., Shankle M.
Conservation cropping systems followed with sustainable management practices have many benefits, such as water use efficiency and infiltration. To improve the soil hydraulic function, several management practices can be adapted, which can restore soil health and prevent water erosion. Integration of cover crops and application of poultry litter is identified as the most commonly used management practices for improving soil health and crop productivity. This study was conducted at the Pontotoc Ridge-Flatwoods Branch Experiment Station with five cover crop treatments to understand the influence of different cover crops like the winter wheat, cereal rye, vetch, cereal rye combined with mustard, and native vegetation on soil hydraulic properties and water quality that can impact the crop yield. For this study, core soil sampling was done after the harvest of the cash crop. Data collection included soil hydraulic and physical properties, such as water-stable aggregates, bulk density, available water content, and saturated hydraulic conductivity, which have been measured after five years of cover crop and poultry litter treatments. The results indicated that the integration of cover crops showed little effect on the soil properties as compared to no cover crop treatment. Data on soil properties were subjected to analysis of variance to assess the effects of cover crops and poultry litter on soil hydraulic responses. There was a significant difference between the fertilizer treatments, and the plots applied with poultry litter performed well at p < 0.05, indicating high infiltration and less bulk density as compared to inorganic fertilizer and no fertilizer treatments. However, the asserted influence of the combined effect of poultry litter and cover crops on soil hydraulic and physical properties is largely unknown.
Cover crops affect irrigation water use in cotton
Year: Authors: Roberts C., Gholson D., Locke M., Spencer D., Quintana N.
Improved cropping systems are needed to reduce irrigation water use of cotton where irrigation water is drawn from the declining Mississippi River Valley Alluvial Aquifer. A study conducted in Stoneville, MS, from 2021 to 2023 is assessing viable cropping systems for the mid-south to conserve irrigation water. Study treatments were established in the fall of 2020 and include reduced tillage, subsoil, winter fallow (RT); strip till, winter fallow; strip till, cover crop; strip till, subsoil, cover crop; no till, winter fallow; no till, cover crop; and no till, minimal surface disturbance subsoil, cover crop. Each treatment was individually irrigated based on tension-based soil moisture status. In the first year of full study implementation (2021), high amounts of timely rainfall made irrigation unneeded. In 2022 precipitation was closer to normal. Cover crops improved soil moisture by as much as 47 kPa compared to the conventional, RT treatment. Compared to all winter fallow treatments, the treatments with a cover crop retained more soil moisture with soil moisture tension being 57% lower. This resulted in more irrigation water used in treatments with winter fallow. There were few differences in lint yield between the treatments, and yields were not improved by increased irrigation. Cover crops can be used to conserve water in cotton without reducing yield in the mid-south during years with normal precipitation.
Assessing agricultural water system in a Mississippi small farm—a pilot study
Year: Authors: Abdallah-Ruiz A., Anderson J.F., Bond R.F., Atwill E.R., Silva J.L.
The proposed US FDA water rule subpart under the Produce safety Rule of FSMA will require an annual assessment of the agricultural water system of covered farms by the grower or other party to identify, evaluate the risks associated with their water system, and develop mitigation strategies to minimize water contamination. The assessment should include evaluation of the location and nature of the water source, water distribution system, type of application method for water, and the time between the last direct application and harvest, and degree of protection of the system from contamination. The latter includes assessing the impact of other users of the water system, animal impacts, adjacent and nearby land uses, and any other factors. The UC Davis Western Center for Food Safety developed an assessment tool which has been modified to the region's reality with the aid of Mississippi State University. In addition, the US FDA developed an online/offline water system assessment. We will also discuss the application of these tools in a pilot study in a small, exempted (from the rule) farm in Mississippi.
Stormwater management in a changing Florida Panhandle
Year: Authors: Albertin A., Stevenson C., Bean E., Deitch M., Reisinger A.J.
The Florida Panhandle has the highest average total rainfall in the state (65"), with average totals increasing in recent years. Limited and aging stormwater management has led to legacy water quality and flooding problems across the region. A need exists for local leaders and stakeholders to better understand how development occurs, its impact on hydrology and water quality, and solutions to mitigate impacts. We developed a regional stormwater education program to build technical capacity among stakeholders to incorporate sustainable stormwater management practices. Our audience includes municipal employees, extension faculty, professional engineers, landscape architects, and residents. We held an in-person stormwater management workshop in 2019 (22 attendees), and 2-part webinar series in 2020 (83 attendees), 2021 (136 attendees), and 2022 (101 attendees). In 2021 and 2022, participants received professional CEU's. Topics taught included hydrology and pollutant load dynamics, green stormwater infrastructure (GSI) and maintenance, low impact development (LID), permitting, planning tools, local case studies, and funding opportunities. Post-workshop 5-month follow-up surveys indicate that attendees are using the information they learn at work and several have modified decisions related to stormwater management based on what they have learned. The annual increase in participation and enthusiasm from stormwater professionals, along with innovative projects designed in local municipalities shows that these workshops are achieving our initial objectives. We are currently planning our 2023 workshop series.
Bountiful "Blues", Plenty of "Purples", Gobs of "Greens", and Modern "Educational Means"? Agroecological & Regulatory Dynamics within 16th Section Lands of the Yazoo-Mississippi Delta
Year: Authors: Heintzman L., McIntyre N.
Established by Jeffersonian Era laws, 16th Section Lands of Mississippi are protected areas that often contain aquatic resources. Historically, these areas were subject to diverse policy, market, and environmental controls; as a consequence, their current agroecological and regulatory patterns are diverse. Land use/land cover (LULC) patterns associated with this diversity are known to influence aquatic resource planning in other protected areas. However, very few studies have examined agroecological and regulatory patterns within 16th Section Lands of Mississippi, and for the few studies that do exist, their foci were forestry or educational caselaw. Even fewer studies have focused on 16th Section Lands of the Yazoo-Mississippi Delta (YMD), and to our knowledge, none have documented spatiotemporal fluctuations in land use/land cover at the landscape scale. This lack of knowledge may hinder enforcement of permitted activities, reduce efficacy of irrigation/groundwater managements, and stymie regional conservation initiatives. Currently, the Mississippi Department of State has administrative oversight of 16th Section Lands, but the lands are managed by local school districts on a parcel basis. Parcels within 16th Section Lands of Mississippi are classified into nine possible categories, each with distinct LULC regulations (permitted activities). Modern leases are subject to decadal evaluation, yet legacy arrangements and indeterminate records complicate educational funding and aquatic resource planning. Therefore, to address coupled scientific and social concerns, we documented landscape changes within 16th Section Lands of the YMD from 2008-2021. We documented dynamics of six socio-ecologically relevant LULC attributes for 16th Section Lands of the YMD: proportionality, variety, baseline stability, sequential stability, embedded parcels counts, and mean rent. We mapped unique patterns among each of the six LULC attributes and identified their subsequent distributions of "hot spot neighborhoods" and "cold spot neighborhoods" Overall, however, wetlands and urban areas featured highest stability, whereas cropped areas had highest mean rents. These results showcase heterogeneity among agroecological and regulatory perspectives for the 103 local school districts that either manage or receive income from 16th Section Lands
The role of vegetation, drying, and rewetting on water and sediment phosphorus concentrations in an experimental stream channel experiment.
Year: Authors: Pawlowski E., Witthaus L., Taylor J., Moore M., McNamara S.
Agricultural drainage ditch networks are an important pathway for nutrients. Changing environmental conditions within drainage ditch networks caused by intermittent drying and rewetting can control nutrient fate and transport. We delivered a phosphorus pulse to six experimental stream channels that subsequently underwent four wet and dry cycles to describe phosphorus retention and mobilization in agricultural ditch environments. Experimental stream channels were filled with sediment from the Mississippi Alluvial Plain and three of the channels were planted with vegetation (Leersia oryzoides) that was allowed to establish prior to the nutrient addition. We monitored discharge, conductivity, pH, salinity, and dissolved oxygen during each of the rewetting periods and during the initial addition of phosphorus salt. Following each wet period, the streams were drained and allowed to dry before the next wet cycle. We collected water samples during each of the rewetting periods and during natural precipitation events that generated flow within the constructed channels. We sampled sediments before and after each rewetting event and measured moisture content, particle size, and water extractable phosphorus on both field moist and air-dried samples. Sediment samples were stratified across channel features (two runs and two pools). Average dissolved phosphorus concentrations were approximately four times higher in unvegetated (0.35 mg L-1) verses vegetated streams (0.09 mg L-1) during the initial wetting event, but subsequent rewetting events had similarly low concentrations (0.01 to 0.03 mg L-1) among both treatments. Sediment increased in phosphorus concentrations following the initial phosphorus addition in all channels. By the fourth wet cycle those concentrations had generally decreased but showed variability throughout each cycle based on channel position and which wet-dry cycle the sediment was collected in. Vegetated sediments did not have as substantial of an increase in phosphorus as sediment from unvegetated channels (2.36 mg kg-1 vs. 4.07 mg kg-1 respectively). These results suggest that both vegetated and unvegetated ditches can store phosphorus through repeated drying and rewetting cycles, but vegetation and likely biological uptake reduces phosphorus in both the water column and sediment. These results show that vegetation may be a promising mitigation tool in ditch networks with intermittent flow but future work is needed to assess phosphorus storage over longer temporal scales.
The influence of flood timing, crop rotation, and soil properties on net N2 flux from temporarily flooded agricultural fields
Year: Authors: Powell J., Simek V., Rosson A., Taylor J., Moore M.
Nitrogen (N) is a vital nutrient necessary for all living organisms. The bulk of N is in N2 gas and not bioavailable. Bacteria facilitate natural fluxes of N from the atmosphere to the biosphere and back through nitrogen fixation and denitrification, maintaining a balanced nitrogen cycle. However, increased fertilizer production and cultivation of N fixing crops has led to excess N in the environment and runoff of excess N from agricultural and urban landscapes can cause many problems, including harmful algal blooms and hypoxia which degrade aquatic habitats. Managing fallow agricultural land in the Mississippi Delta for wildlife wetland habitat in fall and winter can enhance wetland properties that promote denitrification. We collected sediment cores from flooded agricultural fields across ten farms representing different timing of flooding, crop rotations, and soil properties, and incubated them using the same source water to assess how different factors influence N2 flux rates during flooding. We collected water samples from core inflow and outflow lines and measured N2:Ar and O2:Ar ratios using membrane inlet mass spectrometry (MIMS). Net N2 flux and sediment O2 demand were estimated for 30 cores representing replicates from the 10 farms.We then extracted the upper 5cm of the sediment core for characterization of particle size, organic matter content, and carbon, nitrogen and phosphorus concentrations, as well as later DNA extraction to characterize microbial communities. We will present results that seek to link crop rotation, sediment properties, and flooding duration to net N2 flux rates. Understanding how crop rotation, soil properties, and timing of flooding influence N2 flux in agricultural fields managed for fall/winter wetland wildlife habitat can help identify how the nutrient mitigation potential of these conservation practices varies across different conditions throughout the Delta and provide managers with novel ways of managing excess nitrogen in agricultural watersheds.
An experimental evaluation of migratory shorebird effects on soil properties and nitrogen cycling in agricultural fields managed for fall-winter wetland wildlife habitat
Year: Authors: Simek V., Joeksema J., Taylor J.
The global human population continues to grow exponentially, and agriculture will need to become more productive to meet growing food demands. Humans also need clean water and other services that ecosystems provide. This requires future agriculture production to reduce environmental and wildlife impacts through improved efficiencies and best management practices. Migratory shorebirds rely on wetlands throughout North and South America as stopover habitat for rest and refueling during migration. Temporarily flooded farmlands in the Mississippi Delta have proven to be beneficial locations for shorebirds during migrations along the central flyway. This conservation practice also enhances wetland properties that promote excess nitrogen (N) retention or removal. However, little research has been conducted to evaluate how shorebird activity influences N cycling in these temporary wetland habitats on agricultural lands. Shorebirds potentially influence N cycling through several pathways including top-down control of sediment properties via movement and foraging as well as bottom-up processes by recycling nutrients via the deposit of fecal matter. The proposed study will investigate the influence of migratory shorebirds on N cycling in fallow agricultural fields flooded for migratory habitat. We will collect soil cores from plots that either exclude or allow access to shorebirds to assess bird effects on soil properties and invertebrate biomass, as well as different N cycling processes including denitrification and N uptake. Nitrogen cycling processes will be measured using intact sediment core incubations coupled with dissolved inorganic nitrogen (DIN) and dinitrogen (N2) gas measurements. Results from the proposed experiment will provide a better understanding of how interactions between wildlife and habitat created through best management practices may enhance ecosystem services in managed agroecosystems.
Aquifer mapping and drilling depth estimation for monitoring wells using electrical resistivity tomography
Year: Authors: Alim M.S., Mamud M.L., Holt R.M., Wodajo L.T., Hickey C.J., O'Reilly A.M., Samad M.A.
Goodwin Creek is located in the northwestern part of the Yocona Watershed (Panola County, Mississippi) where the Sparta Sand aquifer outcrops. The creek is a tributary of the Yocona River, which flows into the Yazoo River which is a tributary of the Mississippi River. Surface and internal soil erosion are very common problems near the creek due to the surface runoff and groundwater flow. This soil erosion generates soil pipes that collapse and gullies that directly affect the agricultural fields and the pasturelands. To monitor groundwater flow in the unsaturated and saturated zones and to understand surface-groundwater interaction, multidisciplinary geophysical and hydrogeological research is being conducted at Goodwin Creek. An electrical resistivity tomography (ERT) survey was carried out at the study site to map the underlying aquifer, characterize its heterogeneity, estimate drilling depths for proposed monitoring wells, and propose an optimal location for a groundwater extraction well. A 501-m long ERT profile with 3 m electrode spacing was acquired using a mixed dipole-dipole and strong gradient array, starting at the northwestern bank of Goodwin Creek and towards the pastureland. ERT results demonstrate that the aquifer is relatively thin (<10 m) near the creek and thicker (>30 m) under the pastureland. The aquifer outcrops over a short distance (<10 m) in the pastureland but is confined on both sides of the outcrop. Disturbed and undisturbed soil samples were collected down to 1.5 m at multiple locations along the ERT profile. Soil samples collected at the outcrop location are composed of sand and gravel which is consistent with the high resistivity values on the ERT tomograms. Soil samples collected away from the outcrop consisted of clayey soil consistent with low electrical resistivity values from the ERT survey. The underlying aquifer is delineated assuming a threshold value for the resistivity of non-aquifer materials. The aquifer map is used to determine the drilling depths for monitoring wells and provide a recommendation of an optimal location for installing an extraction well.
Alabama Water Institute Overview: Opportunities to collaborate
Year: Authors: Hammett A.
Amy Hammett serves as the Director of Regional and National Collaborations for the Alabama Water Institute (AWI), which is developing a Technology Innovation District with a water tech accelerator and a National Water Training Center in partnership with USGS. AWI promotes water research in areas of remote sensing, biodiversity of aquatic systems, water quality, water and wastewater treatment, groundwater assessment, flood and drought forecasting, hydro-informatics, and disaster planning and management. During this session she will provide an overview of the many water-related programs and projects going at The University of Alabama, including CIROH, the Cooperative Institute for Research to Operations in Hydrology, a partnership between NOAA and the University of Alabama.
Overview and status of the Groundwater Transfer and Injection Pilot Project at Shellmound, Mississippi
Year: Authors: Wren D.G., O'Reilly A.M., Locke M.A., Bolton W.J., Mirecki J.E.
In the Mississippi Delta region (Delta), long-term declines in groundwater levels in the Mississippi River Valley alluvial aquifer (MRVAA) indicate that groundwater-use practices are unsustainable. Managed aquifer recharge (MAR) has potential for reducing groundwater depletion in the Delta. In partnership with local stakeholders and the U.S. Army Corps of Engineers, the USDA Agricultural Research Service is conducting the Groundwater Transfer and Injection Pilot (GTIP) project, which combines riverbank filtration and aquifer storage to capture water from the Tallahatchie River for direct injection into the MRVAA. The system consists of one extraction well near the river, a 1.8-mile transfer pipeline, and two injection wells. The system has a design capacity of 1,500 gpm with 750 gpm sent to each injection well. Monitoring includes continuous groundwater level and temperature in 17 monitor wells (14 MRVAA, 3 Sparta aquifer); semimonthly field parameters (temperature, specific conductance, pH, dissolved oxygen) at six MRVAA monitor wells; monthly water samples for analysis of major ions, metals (Fe, Mn, As), and nutrients (N, P, C) from all monitor wells, extraction and injection wells, Tallahatchie River, and Lake Henry (lake adjacent to the injection wells); and annual water samples for a large suite of trace metals and pesticides from 4 monitor wells and both injection wells. Hydraulic connection between the river and MRVAA is suggested by variations in groundwater level, temperature, and specific conductance. Ambient groundwater prior to operation was less mineralized at the extraction site than the injection site, and water levels in monitor wells near the river showed responses to river stage that were not evident in more distant wells near the injection site. Operation began April 2021, and an 89-day test injecting a total of 550 ac-ft of water has been completed. This resulted in a groundwater mound of 6.9 ft near the injection wells and a drawdown of 4.6 ft near the extraction well, prior to commencement of regional drawdowns in June caused by irrigation pumping. Clogging of the injection wells necessitated periodic backflushing followed by treatment with a dilute oxalic acid solution, which resulted in returning injection well specific capacities to within 85% of initial values. Current plans are to resume operation and data collection for an additional 3 to 6 months. Knowledge acquired during the GTIP project will be used to assess feasibility of a full-scale implementation of MAR technology in the Delta.
Operation and Maintenance of the Groundwater Transfer and Injection Pilot Project at Shellmound, MS
Year: Authors: Cummins B., O'Reilly A.M., Wren D.G.
The Groundwater Transfer and Injection Pilot (GTIP) project is an innovative effort to not only mitigate further depletion of the Mississippi River Valley Alluvial Aquifer (MRVAA), but also to potentially raise water levels in an area of excessive drawdown by artificially recharging the aquifer. This project is a collaborative effort between the U.S. Army Corps of Engineers (USACE) Vicksburg District and the U.S Department of Agriculture - Agricultural Research Service (USDA-ARS). The Pilot Study project site is located in Shellmound, MS, which is approximately 8 miles northwest of Greenwood, MS, and is situated to the west of the Tallahatchie River. <br><br> The system extracts water from within the MRVAA at a natural recharge zone, due to bank filtration of the adjacent Tallahatchie River, and then conveys the water approximately two miles, via subsurface pipeline, to two injection wells where it is re-introduced into the MRVAA. The USACE managed design and construction of the facility and collaborates with USDA-ARS to maintain its operation and conduct maintenance activities. To evaluate the aquifer's response to the artificial recharge, USDA-ARS has been monitoring, sampling, and analyzing data from multiple observation wells near and within the project vicinity.<br><br> Each injection well was receiving water at a rate of 750 gpm and the system was running 24 hours a day, seven days a week for nearly 3 months. The system was functioning as designed; however, after approximately 3 months of continuous injection, both injection wells experienced hydrostatic pressures that exceeded the threshold of the top-stratum blanket of fine-grained sediments, causing cracks due to soil heaving and the presence of boils at the ground surface. Additionally, upon visual inspection of the wells using a downhole camera, the presence of iron-related bacteria and/or iron oxides were observed coating the inside of the well screens. Rehabilitation efforts were performed by USACE Vicksburg District using chemical treatment with a dilute oxalic acid solution at each injection well, and then site repairs were completed using low-strength flowable fill to re-establish the top-stratum blanket. Future planning for optimal operation and maintenance of the GTIP project facility is an ongoing mission to ensure (1) that the data needed to determine feasibility is achieved and (2) that best practices and procedures are identified for use if it is determined that larger scale aquifer recharge is feasible for this region.
Streaming potential response associated with pump-induced surface-groundwater interaction
Year: Authors: Mamud M.L., Hickey C.J., Holt R.M., Wodajo L.T., Rad P.B., O'Reilly A.M., Bolton W., Wren D.
Groundwater flow induced by pumping from an aquifer near a river generates Streaming Potential (SP) signals that can be recorded at the ground surface around a pumping well. The SP signal produced by pumping near a river is influenced by groundwater flow within an aquifer, water flow from the river into the aquifer, and mixing of waters with different chemical compositions and temperatures. SP measurements can be used to identify and quantify characteristic time scales associated with these processes. SP measurements were conducted around a groundwater extraction well drilled for an Aquifer Storage Recovery pilot project located about 40m away from the Tallahatchie River in Shellmound, MS. SP data were recorded at 5 minute intervals using 80 non-polarizing CuSO<sub>4</sub> electrodes in a radial pattern centering on the extraction well. Pumping rates varied from ~300 to ~1500 gallons per minute over a ~4 hour period. Time series and spatial distribution of SP data shows that the river might have interacted with groundwater after 1 hour of pumping at an extraction rate of ~1500 gallons per minutes. This preliminary study suggest that measured SP data can be used to identify surface-groundwater interaction. Furthermore, hydraulic conductivity of aquifer, aquitard and riverbed; specific storage; and hydraulic head could be estimated from inversion of SP data.
Analysis of Long-term Trend and Change points in Maximum Air Temperature within Mississippi River Valley Alluvial Aquifer
Year: Authors: Raju M., Ramirez Avila J.J.
In this study, an attempt is made to investigate long-term trends in maximum temperature within Lower Mississippi River Basin (LMRB) in order to understand the temperature patterns within Mississippi River Valley Alluvial Aquifer (MRVAA) at annual time scale. Daily air temperature data of Global Historical Climatology Network (GHCN) was used to obtain daily maximum air temperature for seventy-six (76) stations within LMRB. Non-parametric statistical tests, Modified Mann Kendall (MMK) and Pettitt were used at 0.05 significance level to assess the trend and change point analysis in temperature variable. Results of MMK trend tests indicated significant increasing and decreasing trends. However, increasing trends outnumbered decreasing trends. Magnitude of annual maximum temperature showed an increase by 0.0005 - 0.0012 ℃ per year over the period 1969 to 2019. Change point analysis results at 0.05 significance level, indicated that increasing shifts occurred since 1985, with decreasing shifts in the year 1988. The results of this study will help in understanding the behavior of temperature patterns in an agriculturally intensive region. Further, the study needs to be extended to explore the trends and changepoints in other temperature variables like mean, minimum to understand the overall pattern of temperature variables within MRVAA to plan and manage the irrigation and crop production.
Characterization of water quality, biology, and habitat of the Pearl River and selected tributaries contiguous to and within Tribal lands of the Pearl River community of the Mississippi Band of Choctaw Indians, 2017–18
Year: Authors: Driver L.J., Hicks M.B., Gill A.C.
The Mississippi Band of Choctaw Indians (MBCI) is a federally recognized tribe with territories in Mississippi and Tennessee. MBCI has sovereign authority over its natural resources and is responsible for protecting the quality of waters within the Tribal lands and restoring impaired waters. The U.S. Geological Survey (USGS), in cooperation with MBCI, collected physical habitat, water-quality, and biological community data at 8 selected stream sites within and contiguous to the MBCI Pearl River community in central Mississippi in 2017 and 2018. Data from MBCI waters were evaluated to establish baseline conditions and to provide a general context of current condition of water quality and biological communities among sites.<br><br>Generally, water-quality concentrations were within natural ranges and were not considered to be chronically stressful for aquatic life, with a few exceptions. Concentrations of total nitrogen and total phosphorus often where slightly elevated at seven of the eight sampled stream sites, indicating nutrient enrichment as a possible stressor and nutrients were frequently highest in Wolf Creek downstream of the wastewater treatment plant that services the Pearl River community. Organic wastewater compounds, including compounds with endocrine-disrupting potential, were detected at low concentrations in water samples from most sites, but were often below the laboratory reporting limit. Likewise, concentrations of most trace elements and PAHs in bed sediment were very low among sites.<br><br>Overall, periphyton, macroinvertebrate, and fish communities appeared to be typical of central Mississippi streams. However, the diversity, composition, and abundance of taxa sampled from Wolf Creek were generally distinctive as compared to other sites. Particularly, the Wolf Creek site downstream of the wastewater treatment plant had the lowest Mississippi-Benthic Index of Stream Quality (M-BISQ) score, indicating a substantially altered macroinvertebrate community compared to the other sample sites and data from a local least disturbed stream. This Wolf Creek site also had relatively lower diversity and higher abundance of some diatom indicator taxa and higher abundance of tubificid worms, indicating possible ecological responses to nutrient enrichment. <br><br>Data and results from this study can be directly used by the MBCI as a baseline from which to compare future data collection efforts and a guide for directing intensive data collection and assessments efforts and for targeting areas for implementation of best management practices.
1937 Homochitto River Project Revisited
Year: Authors: Prud'homme B.
In 1937, the US Army Corps of Engineers began a flood control project on the lower end of the Homochitto River, an east tributary to the Mississippi River south of Natchez. Upon completion, the lower serpentine 20 mile reach was shortened to a straight channel only 10 miles long. The steepened river gradient and increased flow velocity stimulated immediate headward erosion resulting in continuous geomorphic channel adjustments of every tributary along the adjusting river channel, including every tributary stream on the Homochitto National Forest. Riparian habitat along the river has all but completely disappeared and aquatic habitat diversity has been dramatically homogenized. Transportation systems and other infrastructure have suffered extensive damage, valuable property has been lost, and untold millions of cubic yards and tons of sediment have gone downstream into the Mississippi River. Potential may exist for the geomorphic trend of the river and tributaries to cease and reverse.
Understanding the Effects of Soil Moisture on Iron Deficiency Chlorosis (IDC) in Soybean
Year: Authors: Waldrep K., Tagert M.L., McCoy J., Harrison M.
Iron deficiency chlorosis (IDC) of soybeans is a frequent problem in certain areas of the United States, including the Blackland Prairie regions of Mississippi. Previous research has found that the severity of IDC in soybeans can be related to pH, temperature, CaCO<sub>3</sub> content, and moisture in the soil. However, even with these contributing factors identified, variety selection for tolerance has been the primary strategy for alleviating the effects of IDC. This study began in 2019 and focuses on a cropping system approach to manage the effects of IDC and thus increase grain yield in dryland soybeans. The project was established as a split-plot design, with seven different cropping systems as the main plots and six soybean varieties as the subplots. Little field-scale research has been conducted to understand the effect of soil moisture on IDC symptoms. This project evaluates the relationship between soil water tension and IDC severity across the seven cropping systems. Visual ratings and chlorophyll readings were recorded weekly (weather permitting) to evaluate IDC symptomology, and soil water tension was measured continuously throughout the growing season. Soil water tension was measured using Watermark granular matrix sensors installed at 30.5- and 61-cm depths—one set in a tolerant variety subplot and one set in a susceptible variety subplot. The sensors were connected to Watermark 200SS dataloggers and set to record each hour. Soil water tension is being compared to IDC visual ratings and grain yield for each cropping system to identify how soil moisture affects IDC severity.
Incorporating Cover Crops into Successful Corn Production Systems
Year: Authors: Mullican N., Larson E., McCoy J., Lemus R., Krutz J., Bond J., Maples W.
Growing cover crops may restrict planting opportunities and corn productivity, particularly in high rainfall environments common in the Midsouth region of the U.S. This study was conducted to identify factors and management practices needed to successfully integrate cover crops into Midsouth corn production systems without sacrificing economic returns or increasing production risks. Field studies were conducted to evaluate effects of cover cropping cultural practices and species on corn growth and productivity in Mississippi in 2021. Various seeding methods affecting cover crop distribution, including strip tillage, had little influence on corn production systems. However, the presence of living cover crops at planting stunted corn growth and development when they were not terminated by herbicides applied at least two weeks prior to planting. This interference reduced corn grain yield compared to where no cover crops were grown, or cover crops which were terminated at least four weeks in advance of planting. These preliminary findings indicate that growing cover crops can hinder our ability to produce corn and implement early planting systems. Abundant vegetation produced by cover crops will shade the soil, restricting solar warming, which hinders corn seedling establishment and growth. Thus, growers seeking to gain benefits associated with growing cover crops must use herbicides to terminate cover crops at least a couple weeks in advance of planting in order to maintain corn productivity associated with early planting systems tailored for high rainfall, southern climates.
First-Year Cover Crops, Strip-Till, and No-Till Affected Cotton Yield and Runoff Water Quality
Year: Authors: Roberts C., Gholson D., Locke M., Spencer D., Steinriede R.W., Krutz L.J., Pieralisi B., Crow W.
Conservation cropping systems have many benefits; most of these are associated with water use, infiltration, and water runoff quality. Despite these potential benefits, research and development of effective conservation cropping methods for cotton producers in the Mid-South are limited. A study is being conducted in Stoneville, MS, from 2021 to 2023 to determine how cotton yield, water use efficiency (WUE), and nutrient and soil in water runoff are influenced by conservation tillage and cover cropping systems. Study treatments were established in the fall of 2020 and included reduced tillage, subsoil, winter fallow (RT), strip till, winter fallow (ST), strip till, cover crop (ST, CC), strip till, subsoil, cover crop (ST, SS, CC), no till, winter fallow (NT), no till, cover crop (NT, CC), no till, and minimal surface disturbance subsoil, cover crop (NT, SS, CC) In the first year of full study implementation (2021), lint yield was decreased in no-till (NT) treatments by up to 16% (1382 kg ha<sup>-1</sup>) compared to conventional reduced tillage (RT; 1647 kg ha<sup>-1</sup>). Strip-tillage coupled with cover crops did not have an impact on yield compared to RT. Tailwater runoff from a rainfall event in late August did not differ between treatments. Preliminary observations indicate that glyphosate concentration in runoff water is greater following a burndown application of glyphosate in NT,CC and NT,SS,CC treatments (907 μg L<sup>-1</sup>) than in RT treatments (482 μg L<sup>-1</sup>). Few conclusions can be made regarding irrigation WUE since irrigation only occurred in a single RT plot due to exceptional rainfall. Since this is the first complete year of treatment implementation, treatment effects are expected to become more apparent as this long-term study continues.
Establishing a model system to investigate eutrophication and invasion of southeastern US floodplain wetlands
Year: Authors: Sample A., Ervin G., Turnage G.
Increased nutrient inputs into the Mississippi River resulting from extensive agricultural activity and loss of wetlands in the Lower Mississippi Alluvial Valley (LMAV) can be mitigated via wetland restoration initiatives. The goal of this study was to establish a model system for studying the effects of species invasion and eutrophication on floodplain wetlands in the southeastern US. A multi-year mesocosm study was developed in which two regionally non-weedy emergent macrophyte species—<em>Juncus effusus</em> (Common Rush) and <em>Schoenoplectus tabernaemontani</em> (Softstem Bulrush)—and two common weedy emergent macrophyte species—<em>Typha latifolia</em> (Broadleaf Cattail) and <em>Phragmites australis</em> (Common Reed)—were chosen as model species. The first year of the mesocosm study was aimed at determining baseline growth and nutrient removal from the water column for each species, grown in a monoculture setting, under a standardized flooding and nutrient availability regimen based on water quality studies and flood duration data from the LMAV. Results from the first year showed clear differences in growth patterns between the weedy and non-weedy species. As expected, the weedy species exhibited faster radial spread and reached taller maximum heights than the non-weedy species. The non-weedy species also showed relatively consistent growth rates through the growing season, whereas the weedy species displayed relatively short bursts of rapid growth prior to flowering. Despite those differences in growth, we saw no differences in nutrient removal from the water column based on species or species designation (weedy or non-weedy), with over 50% removal of total nitrogen by all species. This work will be followed by simulated scenarios of species invasion in the second year (monoculture and mixed species mesocosms) and eutrophication (mixed species mesocosms with baseline and increased nitrogen concentrations) in the third year. The results of this work should be useful for wetland managers regarding species selection for project design and in planning adaptive management strategies considering these two major wetland management challenges.
Aquatic vegetation management to enhance multiple-user benefits of southeastern wetlands
Year: Authors: Ervin G.N., Turnage G., Lazaro-Lobo A.
Resource managers of public lands, such as national wildlife refuges, are tasked with meeting multiple use needs of the fish and wildlife that reside on these lands, as well as the people who utilize those lands for recreational activities such as fishing, boating, and wildlife watching. Biologists at the Sam D. Hamilton Noxubee National Wildlife Refuge (NNWR) have identified the dominance of certain problematic aquatic plants as a key obstacle to achieving these multiple use needs in lakes and associated wetlands on this and other southeastern wildlife refuges. Few methods are currently known that allow the control of some of the problematic aquatic plant species that they encounter, while simultaneously enhancing the diversity of desirable species, maintaining water quality, and providing diverse aquatic habitats that are needed for many species of wildlife and for human users of these facilities.<br><br>This project was aimed at determining optimally effective methods of managing invasive and problematic aquatic plants to enhance wetland plant diversity in a way that improves the quality of wetlands as wildlife habitat and sources of recreational use, while also minimizing potential negative impacts on water quality and desirable native plant species. We tested a variety of chemical control measures (herbicides) to reduce the abundance of key nuisance plant species, while attempting to minimize negative impacts on key water quality parameters (e.g., dissolved oxygen, nitrogen, and phosphorus). We found that all three herbicides tested gave long-term reduction of white water lily and water shield, but a timing mismatch in the phenology of these species and American lotus resulted in failure to control the latter species. None of the water quality parameters that were monitored indicated substantial negative impacts of the herbicide treatments.
Surveys for Invasive Aquatic and Native Marine Vegetation on the Mississippi Barrier Islands
Year: Authors: Turnage G., Sample A.
Barrier island lagoons may act as refugia for seagrass species; many of which are vital components of marine ecosystems in the Gulf of Mexico and the Mississippi Sound. Seagrass beds serve as feeding and spawning habitat for many species of marine fauna (i.e., fish and invertebrates) and reduction of seagrass beds can have a cascading effect on ecosystem processes (e.g., fish feeding) that can affect economic opportunities by reducing commercially and recreationally important fish species (e.g. speckled trout) that utilize this habitat. Unfortunately, lagoons may also be invaded by aquatic invasive plant species AIS capable of surviving brackish water environments (i.e., torpedograss, common reed, and Eurasian watermilfoil) that can form dense plant beds that shade out and kill native plant species. Loss of ecosystem function has been documented in many systems that have AIS present, including brackish and saline habitats, suggesting that AIS invasion could further reduce seagrass abundance in island lagoons such that these sites no longer function as nursery populations that replenish seagrass beds in the Mississippi Sound. The goal of this project was to survey the aquatic and marine vegetation in select lagoons on the four major barrier islands (Petit Bois, Horn, Ship, and Cat) of Mississippi to 1) determine the aquatic/marine plant community of each lagoon and 2) determine if AIS were present in these systems. Islands were surveyed using the point-intercept method in the fall of 2020 under research permit #GUIS 00283. Twelve lagoons over 0.4 ha (1 ac) in size were identified from historical satellite imagery. Six reference sites in the Mississippi Sound were identified adjacent each island and also surveyed to generate baseline density of seagrasses, against which seagrass densities from individual lagoons were statistically compared. All lagoons had vegetation present with Shoal grass (native) and torpedograss (AIS) being the most prevalent species. Seagrass was recorded in 58% of lagoons with 70% of those populations potentially serving as nursery populations for offshore sites adjacent to each island and approximately 40% serving as nursery sites across the Mississippi Sound. However, AIS were present in 66% of lagoons and co-occurred with seagrass populations in 25% of lagoons. To our knowledge, this is the first work to document AIS co-occurring with seagrasses on the Mississippi Barrier islands. Future reduction of AIS in lagoons may allow for subsequent colonization by seagrasses which could further increase the abundance of nursery seagrass populations in the Mississippi Sound.
Engaging partners and empowering communities: establishing a well water network in Alabama
Year: Authors: Curl J.N.
Cooperative Extension Services serve as a repository of information to a wide breadth of clients nationwide in search of reliable, science-based materials. In Alabama, there were limited resources for private well owners prior to development of the Alabama Private Well Program (APWP) in 2020. Administration and Extension field staff indicated the need for a program to assist county offices in addressing the needs of a client base previously overlooked. <br><br> APWP follows the precedent of established Extension led well water programs. The APWP's purpose is to build capacity to County based Extension professionals through trainings and resources to address frequent questions and concerns from well owners. <br><br> As the pilot stage of the program continues, entities from across Alabama continue to express interest in well water educational materials. This is evident in the diverse audience that attended the well water webinar series, initially intended for Extension personnel. Professionals from regulatory agencies, non-profit organizations, power utilities, and financial institutions were strongly supportive of the program and aided in the development of a multi-agency and Extension network. <br><br> Approaching its third year, the APWP will begin hosting workshops throughout the state for private well owners. The APWP workshops will give an opportunity to well owners to have their water tested, while simultaneously creating a database of demographic information and well characteristics to be used to plan subsequent workshops and determine where bacterial contamination is most present in the state. APWP directly benefits homeowners who rely on private wells for drinking water while addressing a statewide need for well water resources beyond homeowners. This presentation will explore the approach to collecting well characteristics and the impact of a multi-agency partnership on building a new Extension program.
Microbial Contamination of Drinking Water Supplied by Private Wells after Hurricane Harvey
Year: Authors: Jones C.N., Pieper K.J., Rhoads W.J., Rome M., Gholson D.M., Katner A., Boellstorff D.E., Beighley R.E.
Hurricane Harvey made landfall on the Texas Gulf Coast on August 25, 2017, as a Category 4 hurricane and caused widespread flooding. We explored spatial and temporal distributions of well testing and contamination rates; relationships between contamination and system characteristics and recovery behaviors; and efficacy of mitigation strategies. We estimated that over 500,000 well users (~130,000 to 260,000 wells) may have been affected, but only around 15,000 well users (~3,800 to 7,500 wells) had inundated systems based on inundation maps. Total coliform occurrence was 1.5 times and Escherichia coli was 2.8 times higher after Hurricane Harvey compared to baseline levels. Microbial contamination was more likely (1.7-2.5 times higher) when wells were inundated and/or residents felt their water was unsafe. Although more wells in urban counties were affected, E. coli rates were higher in wells in rural counties. Disinfection did not always eliminate contamination, highlighting concerns about the implementation and efficacy of chlorination procedures. Despite this extensive well testing conducted after Hurricane Harvey, we estimate that only 4.1% of potentially affected wells were tested, underscoring the magnitude of recovery assistance needed to assist well users after flooding events.
Evolution of Water Disinfection Practices
Year: Authors: Hutcherson D.
In 1900, diarrhea and enteritis, was a significant cause of death in the US. It was through drinking water disinfection and treatment that we have been able to almost eradicate these diseases—one of the greatest public health achievements of the 20th century.<br><br>We look back in history at how water has been treated (or not) to make it safe. We will look at factors affecting water sanitation; from source to tap. <ul><li>What is the best source of water?</li> <li>Can the source be protected from contamination?</li> <li>Is treatment feasible for the contaminants present?</li> <li>Is reintroduction of contaminants possible?</li> </ul> We'll look at this and more concerning water treatment.
Assessing background trends in monitoring wells at the groundwater transfer and injection pilot project located in Shellmound, Mississippi
Year: Authors: Purdom K., O'Reilly A., Wren D.
The Groundwater Transfer and Injection Pilot project (GTIP) is focused on testing the effectiveness of direct injection of groundwater into the Mississippi River Valley Alluvial Aquifer (MRVAA). The project is in Shellmound, MS approximately 8 miles northwest of Greenwood, MS and west of the Tallahatchie River. The MRVAA is the primary source of irrigation water for the local farming industry, and water levels in the MRVAA have gradually declined for decades. Prior to beginning the pumping phase of the project, the monitoring wells in the surrounding area had their water levels continuously recorded for a year. The data included represents a full growing and irrigation season, as well as the off season in the winter. Having data from all seasons allowed for extensive understanding of how the local groundwater levels were impacted by irrigation, weather patterns, and Tallahatchie River stage. Groundwater levels during the summer 2020 growing season prior to injection show frequent drawdown events contributing to decreases of 1-4 ft in water level; over the following fall-spring off season water levels recovered 1-3 ft. Trends in groundwater levels prior to injection indicate that water levels near the injection site exhibit at least one month of lag time relative to the levels near the extraction site and Tallahatchie River. We will present water level trends in the GTIP project area from the year prior to the pumping phase of the project and identify important trends resulting from climate and farming practices.
Numerical study of groundwater flow and heat transport to assess the hydrogeological effects of the groundwater transfer and injection pilot project in the Mississippi Delta
Year: Authors: Fang J., Al-Hamdan M.Z., O'Reilly A.M., Ozeren Y., Rigby J.R.
In the Mississippi River Valley alluvial aquifer (MRVAA), declines in groundwater levels caused by agricultural irrigation have been observed and reported for the past several decades, indicating that the current practices for groundwater resources management are not sustainable. To mitigate this problem, the Groundwater Transfer and Injection Pilot (GTIP) project was initiated by the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS) at Shellmound, Mississippi, which consists of one extraction well, two injection wells and 17 observation wells. An experimental operation was conducted to test the feasibility of managed aquifer recharge (MAR) technology, which included measurement of groundwater hydraulic heads and groundwater temperatures in the observation wells. In this study, the hydrogeological properties of the study area are obtained through the coupled inverse modelling of groundwater flow and heat transfer. The variably saturated groundwater flow is simulated by CCHE3D-GW developed by NCCHE, The University of Mississippi, and heat transport is simulated using the MT3D-USGS developed by the USGS. A weighted multiple-variate least squares objective function, which is used to minimize the discrepancies between the measured and simulation results, is formulated for the inverse problem. To obtain a unique solution, Tikhonov regularization is applied, in which the high-resolution data derived from an airborne electromagnetic geophysical survey measured by USGS is adopted as prior information. The local scale hydrological processes governing extraction and injection, i.e., the infiltration flow of water from the Tallahatchie River to the MRVAA and the spread of injection water in the aquifer, are then analyzed based on the calibration results, which will provide detailed understanding of the hydrogeological effects of the GTIP Project to complement other regional modeling activities.
Watershed planning for sustainable irrigation expansion in Alabama
Year: Authors: Newby A., Ellenburg L., Estes M.
Although the Southeast enjoys more annual rainfall than most of the U.S., it still experiences periodic droughts and the rainfall distribution throughout the year is not ideal for agriculture. In Alabama, agriculture is further impacted because of relatively poor water holding soils and lack of widespread irrigation. The need to pursue sustainable irrigation expansion and resource conservation in water rich states such as Alabama has been identified in farmer listening sessions. According to the irrigation status of harvested cropland in a agricultural census, Florida had about 1.3 million acres under irrigation, Georgia irrigated around 1.2 million acres, Mississippi had 1.8 million and Alabama had only 162,000 irrigated acres.<br><br> The Natural Resources Conservation Service (NRCS) Alabama office is working with the Alabama Soil and Water Conservation Committee to allocate financial assistance to sustainably expand irrigation in Alabama. Auburn University and the University of Alabama in Huntsville are supporting the effort through the development of a statewide resource assessment and follow up watershed plans for selected HUC-8 basins. The irrigation watershed plans examine alternatives for increasing acres of on-farm irrigation, identify natural and cultural resources that might be negatively impacted by expanded irrigated agriculture, estimate economic benefits, and evaluate environmental sensitivity concerns. Data at the HUC-12 level is provided where available to assist with the determination of sustainable expansion. Farmers selected for participation are prioritized using recommendations from the watershed plans and by categories including access to water and a record of stewardship practices.<br><br> The plans are developed with coordination and guidance from diverse stakeholders including government agencies, non-government organizations, landowners, and others that are interested. This presentation will cover aspects of the overall project, provide updates on completed watershed plans, and share future steps in planning for sustainable water use in Alabama's agricultural industry.
Bankfull discharge: Contrasting regional curves and frequency curves
Year: Authors: Ramirez Avila J.J., Achury S.O., Raju M., Chaux L.C.
Regional Curves are stream restoration practitioners' tools that relate measured stream morphology, discharge, and drainage area. These are valuable tools for geomorphic assessment to analyze departure from equilibrium conditions in disturbed ecosystems and for restoration planning to determine approximate channel dimensions and discharge. The relationship between the drainage area and the magnitude of the flow observed at bankfull stage in reference stable reaches is a fundamental key to achieve a baseline restoration design. Research on bankfull discharge in the US has resulted in general agreement that the annual series bankfull discharge recurrence intervals are approximately equal to a 1.5-year event. A study is performed to evaluate if the 1.5-year bankfull discharge recurrence interval assumption represents the flow observed at bankfull stage in reference sites assessed to estimate the Regional Curves. Datasets used to develop Regional Curves in different physiographic regions of the US have been collected and used to generate stream flow and watershed characteristics reports by using the web application USGS StreamStats. Field measured bankfull flow discharges for each individual location are correlated with the peak flow discharge frequency curves reported by StreamStats to identify a corresponding return period. Preliminary results indicate that the peak flow discharge observed at a return period of 1.5 years overestimate the magnitude of the flow observed at bankfull stage. Similarly, the determination of a return period that better represents the magnitude of the flow at bankfull stage for different locations varies among physiographic regions and more importantly, to the level of urban development of the drainage area.
Impacts of livestock management areas on stream water quality in the Catalpa Creek
Year: Authors: Chaux L.C., Ramirez Avila J.J., Achury S.O., Czarnecki J., Schauwecker T.
Livestock production is a predominant economic activity in the United States (US). However, it is also considered one of the agricultural activities that contributes to pollution of the nation's waters. It's currently estimated that around 55% of the assessed US streams have been impaired by sediments and nutrients coming from non-point sources via overland flow. A study was established to assess the spatiotemporal variation in water quality under baseflow conditions in the mainstream flowing through the MSU Joey Bearden Dairy Research Center. Water quality monitoring consisted of biweekly grab sampling and in-situ testing (dissolved oxygen, pH, turbidity, specific conductivity, total dissolved solids) from July 2019 to March 2020. Laboratory analysis of water samples included assessment of total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN) and coliforms concentration. Water quality parameters were contrasted with state and national recommended water quality criteria. Results suggest the study reach is unable to meet the nutrient requirements for the assigned designated use. Mean concentrations of TP were 10 and 6 times higher than the nutrient criteria during the summer and winter months, respectively, while TN concentrations were 4 and 2 times higher. Overall, colony forming units of Escherichia coli exceeded in up to 19 times the corresponding criteria. In addition to the impairment on water quality, field observations have evidenced the unrestricted access of animals to the stream has negatively affected stream hydrology (i.e. higher runoff due to compacted soils) and geomorphology (i.e. streambank erosion). Monitoring efforts after implementing a 30-ft riparian zone buffer will be contrasted to evaluate the BMP effectiveness.
Evaluation of the utility and performance of an autonomous surface vehicle for mobile monitoring of waterborne biochemical agents
Year: Authors: Wolfe J.S., Chesser Jr. G.D., Lowe W., Moorhead J., Turnage G., Dash P., Moorhead R.
The need for real-time monitoring and management of water quality in inland and coastal marine environments is increasingly significant due to increases in land utilization which can negatively impact aquatic ecosystems from surface water runoff. Conventional water quality monitoring methodologies are laborious and expensive, requiring in situ monitoring stations and/or specialized manned vessel sampling missions at fixed locations and resultant laboratory analysis of water samples. These conventional methods are limited in their ability to gather high resolution spatio-temporal data. Multi-purpose autonomous surface vehicles (ASVs) provide a powered platform for sensors/instrumentation and serve as mobile sampling stations that enhance spatial and temporal data gathering capabilities. Solar powered ASVs provide long endurance continuous operations capabilities. However, commercially available solar powered ASVs are limited, and ASV autopilot navigational accuracy is affected by environmental forces (wind, current, and waves) that can alter trajectories and negatively affect spatio-temporal resolution of water quality data. The goal of this research was to evaluate the utility and navigational performance of a commercially available solar powered ASV (SeaTrac SP-48) equipped with a multi-sensor payload to operate autonomously under varying conditions of environmental forces. The specific objective was to evaluate the ability of the ASV to accurately and repeatedly maintain established A-B line transects under varying environmental conditions, where lateral deviation from a planned linear route was measured and expressed as cross-track error (XTE). Three testing scenarios by location (inland reservoir, riverine, and coastal) were considered to comprehensively evaluate the vessel under varying environmental conditions of wind, waves and current that could potentially alter trajectory and/or position. Results indicated mean XTE for A-B line transects tested across all scenarios of environmental conditions did not exceed 2.39 m. This work serves to provide a conceptual framework for development of spatial and temporal resolution limitations of ASVs for real-time monitoring campaigns and future development of station keeping and adaptive sampling technologies.
Use of geophysics and UAS-based thermal for mapping potential underseepage of levees
Year: Authors: Counts R., Davidson G., Yarbrough L.D.
Subsurface erosion due to underseepage during large floods, particularly through piping and the formation of sand boils, poses a significant threat to the integrity of floodplain levees in certain geologic settings. Research using natural geochemical tracers indicates that seepage beneath levees can follow both shallow and deep flowpaths. Though effective, tracking geochemical tracers is somewhat labor intensive and takes time. This project uses ground penetrating radar (GPR) and unmanned aerial system (UAS) imagery, which can be rapidly deployed with real-time viewing of the data as it is acquired, to test their effectiveness in mapping seepage and piping flowpaths. In 2019, the lower Mississippi River valley experienced significant and sustained flooding. During this historic event, GPR profiles and UAS thermal imagery were acquired in between Mississippi River mainline levees and multiple active sand boils north of Vicksburg, MS to identify active seepage flow paths and locate new sand boils in heavily vegetated areas. Despite recent mitigation efforts in the study area, which included constructing a 3-m thick clay pad over the region of older sand boil formation, new sand boils formed on the floodplain surface beyond the edge of the mitigation area during the 2019 flooding. GPR surveys using 160 MHz and 450 MHz hyperstacking antennae and UAS thermal imagery were acquired in between the actively flowing sand boils and the levee with promising results. Although wet, clay-rich soils are among the worst conditions for GPR, the 160 and 450 MHz antenna imaged to depths of 14 m and 6.5 m, respectively, and revealed multiple anomalies that could be seepage flowpaths. Additionally, actively flowing sand boils were apparent in the thermal imagery. Not only can GPR and UAS surveys be rapidly deployed, they can also cover very large areas in short time spans, and our proof-of concept results show these methods could be valuable tools for real-time levee assessments during flood conditions.
Development of a Vadose-Zone-Sensitive model by means of a radio spectrum recycling
Year: Authors: Boyd D.R., Kurum M.
A longstanding research focus within hydrology is the remote sensing of soil moisture across the entire depth of the vadose zone at sufficient spatial and temporal resolutions to address human needs for crop growth, water management, drought prediction, and many other research areas. While many forms of remote sensing can provide insight into vegetation health and surface water availability, microwave remote sensing is perhaps the most mature method for detecting water content within Earth land structure's due to its penetrative capabilities. While active microwave remote sensing is capable of performing such remote sensing measurements at desirable resolutions, such systems cannot be easily proposed due to the cost of building such a network in addition to the competing frequency space between commercial and public ventures.<br><br>The signals of opportunity (SoOp) method is a form of radio spectrum recycling that allows for the reuse of active microwave signals from systems designed for navigation and communication to science application systems. The SoOp method allows for high spatiotemporal resolution microwave measurements while maintaining a low size, weight, power, and cost for individual receiver systems. Such systems have shown success in recent years for estimating surface soil moisture in recent years through machine learning, and future SoOp missions and experiments dedicated for surface and root-zone soil moisture are expected. The development of models which are capable of recreating these bistatic scenarios over land structures is an area of ongoing research within the remote sensing community.<br><br>This research showcases the development of a vadose-zone-capable model for estimating changes in soil moisture by means of a generalized, SoOp modeling suite developed at Mississippi State University. This model is an upgraded variant of the SoOp Coherent Bistatic scattering model (SCoBi) which allows for simulation of bistatic scattering within multilayered soil moisture profiles and vegetation structures across land surfaces. Added features to the model will enable the simulation of varying land structures across Earth structures with sensitivity to features such as topography, land cover classification, and surface roughness. This model is anticipated to help explore the sensitivity of multifrequency SoOp systems to variations in soil moisture profiles over multiple land surfaces. Sample simulations will be presented at the conference.
Invasive alligator weed (Alternanthera philoxeroides) in the southeastern United States: a future research plan
Year: Authors: Schmid S.A., Ervin G.N., Turnage G.
Invasive aquatic plants have the capacity to fundamentally alter the structure and function of the systems they inhabit. <em>Alternanthera philoxeroides</em> (alligator weed) is an emergent aquatic amaranth that is native to South America and invasive in many regions globally. Historically, invasion (and management as a result) has been most intense in the southeastern United States, however, there are substantial invasive ranges in Australia, New Zealand, and East Asia. In invaded sites, alligator weed can alter system structure by forming dense mats of shoots at the water's surface. These mats can displace native plants that are important food and habitat for aquatic fauna. In the United States, biocontrol of alligator has primarily focused on the insect vector <em>Agasicles hygrophila</em> (Alligatorweed flea beetle). The success of alligator weed biocontrol in geographic locations with climate conducive to the survival of the flea beetle led to global adoption of this strategy in areas of similar climate. This allowed aquatic plant managers in these areas to shift their focus and resources to other target species. However, alligator weed continues to colonize newer and more environmentally diverse ecosystems with climate not suitable for the survival of the flea beetle. This poses new problems for alligator weed management. This presentation 1) summarizes the historic research and management paradigms for alligator weed, 2) contextualizes the literature with the current status of alligator weed, 3) discusses the future of alligator weed biocontrol in the southeastern United States, and 4) exhibits preliminary research efforts at Mississippi State University including alligatorweed phenology and integrated management utilizing herbicides and a second insect vector, <em>Amynothrips andersoni</em> (Alligatorweed thrips).
Effects of select herbicides for management of American frogbit grown in mesocosms
Year: Authors: Turnage G., Lazaro-Lobo A., Blassingame B., Robinson O., Calhoun K., Ervin G.N.
<em>Limnobium spongia</em> (frogbit) is a free-floating aquatic plant that can produce extensive floating mats that cause negative ecological, social, and economic impacts, which can have negative effects on aquatic fauna (i.e., dissolved oxygen depletion) and restrict waterbody access, navigation, and recreational usage by humans. Literature describing effective control measures for frogbit is minimal. Control efficacy of high and low doses of seven foliar applied herbicides (2,4-D, florpyrauxifen-benzyl, flumioxazin, glyphosate, imazamox, imazapyr, and triclopyr) were evaluated in a mesocosm setting in the summers of 2018, 2020, and 2021. Both emergent and submersed frogbit biomass were reduced 99 to 100% by imazamox (0.56 and 1.11 kg a.i. ha<sup>-1</sup>) and imazapyr (0.42 and 0.84 kg a.i. ha<sup>-1</sup>) 8 weeks after treatment (WAT) compared to non-treated reference plants. Triclopyr (6.71 kg a.i. ha<sup>-1</sup>) reduced frogbit biomass 92% and flumioxazin (0.42 kg a.i. ha<sup>-1</sup>) reduced biomass 87 to 93% compared to reference plants. 2,4-D (2.12 and 4.24 kg a.i. ha<sup>-1</sup>), glyphosate (2.83 and 5.67 kg a.i. ha<sup>-1</sup>), triclopyr (3.36 kg a.i. ha<sup>-1</sup>), florpyrauxifen-benzyl (0.02 and 0.05 kg a.i. ha<sup>-1</sup>), and flumioxazin (0.21 kg a.i. ha<sup>-1</sup>) did not reduce frogbit biomass 8 WAT compared to reference plants. Future research should consider the efficacy of different herbicide combinations to control frogbit, as well as the role of diluent volume per unit area, especially with imazamox and imazapyr. Field studies also will be useful in determining whether the results observed in this study will translate to management of frogbit in natural settings.
Evaluating the response of invasive flowering rush (<em>Butomus umbellatus</em>) cytotypes to chemical control measures
Year: Authors: Hockensmith J., Turnage G., Shoemaker C.
Establishment and spread of invasive species has affected ecosystems across the globe. These intruders compete with native species for resources, which often leads to reduced biodiversity as well as other environmental issues. Flowering Rush (Butomus umbellatus) is one such species that has invaded the northern United States and Canada. Flowing Rush is a perennial, aquatic species that can be found growing along the shoreline of lakes and other waterbodies. In North America, two distinct cytotype populations occur: diploid and triploid. These cytotypes differ in key anatomical and physiological properties. Despite these differences, current best management practices of chemical control are based solely off research conducted on triploid populations, which account for only 29% of flowering rush populations in North America. In this study, we assessed the effect of two commonly used chemical control measures for aquatic plants, Diquat and Endothall, on diploid and triploid cytotypes. After establishment and subsequent herbicide application, plants were followed to eight weeks post treatment. At this time the plants were harvested to assess the efficacy of the treatments on above- and belowground biomass accumulation, in addition to belowground asexual rhizomatous bud production. We observed that when treated with herbicides, bud production in diploid plants increased, while bud production in triploid plants was unaffected. Additionally, in diploid Flowering Rush, higher concentrations of Diquat and Endothall increased bud production compared to control and low concentration treatments. Both Diquat and Endothall reduced the overall above- and belowground biomass. Our results suggest that diploid and triploid populations display different reactions to chemical controls and that further research is needed to elucidate these differences.
Irrigation threshold and cover crop impacts on corn production in Mississippi
Year: Authors: Russell D., Kaur G., Singh G.
The Mississippi River Valley Alluvial Aquifer (MRVAA) is the main source of groundwater for irrigation in the Mississippi Delta region. Increases in irrigated crop acreage, as well as frequent droughts throughout the growing season, have caused continual groundwater decline in this aquifer. The objective of this study was to determine if combinations of irrigation scheduling thresholds (-40 kPa, -90 kPa, and no irrigation control) and cover crops [cereal rye (<em>Secale cereale</em> L.), hairy vetch (<em>Vicia villosa</em> R.), wheat (<em>Triticum aestivum</em> L.) + radish (<em>Raphanus sativus</em> L.) + turnip (<em>Brassica rapa</em> L.) mix, and no cover crop control] could improve corn grain yield and quality, water productivity, and irrigation water use efficiency. A field experiment was conducted from 2019 to 2021 at the National Center for Alluvial Aquifer Research in Leland, MS, and the experimental design comprised of a randomized complete block with four replications. In 2020, cover crops reduced corn yield by 9 to 26% compared to the no cover crop control. Minimal or negative impacts from cover crops were also observed for water productivity, irrigation water use efficiency, and corn grain quality in the first year of the study. In 2021, -40 kPa irrigation treatments had 8 and 9% higher corn yield compared to no irrigation and -90 kPa irrigation treatments, respectively. No irrigation treatments showed 6 and 17% higher water productivity compared to -90 kPa and -40 kPa, while hairy vetch was at least 7% higher in water productivity among cover crop treatments in year two of this study. While cover crops showed improvements over the course of two years, no cover crop treatments under the -90 kPa irrigation threshold was the most profitable treatment when averaged over both years. Continued evaluation of cover crops and irrigation thresholds is needed to determine which combination is best for corn production in the Mississippi Delta region.
KTS Wireless/High Yield Ag Solutions
Year: Authors: Koos W.
Since 2014 KTS Wireless (KTS) and subsidiary High Yield Ag Solutions (HYAG) have been collecting and managing data from sensors connected to our wireless products. The data has been delivered to our cloud-based servers where web applications have been created to provide decision making tools for growers and researchers. We have worked closely with Delta F.A.R.M. and Mississippi State University scientists to provide insight into water related agricultural field inputs and outputs. In addition to decision support insights for growers, the raw data is compiled for ease of direct download for research purposes. The sensors and tools include water levels, soil moisture and salinity, well flow rates, outflow pipe flow rates and volumes with water sampler triggering from changes in flow rate, irrigation pump control and weather data from our own agricultural weather station as well as third party sources. Our intent has been to develop a central data platform for capturing agricultural water data in a practical and affordable manner that provides value to growers and researchers alike.
Inventory of on-farm water storage systems for irrigation in two Mississippi agricultural regions
Year: Authors: Tagert M.L., Brock M.L., Paz J.O., Lo T.H., Krutz L.J.
Surface water is being increasingly used for irrigation in two agricultural regions of Mississippi—the Mississippi Delta region and northeast Mississippi. Producers in both areas rely on supplemental irrigation to meet crop water demands and reduce risk during the summer growing season. In the Mississippi Delta, groundwater from the Mississippi River Valley Alluvial Aquifer (MRVAA), a shallow subsurface aquifer, serves as the main source of water for irrigation. The MRVAA experiences the second highest daily pumping rate in the United States at 45,803 million liters per day. Over 60% of cropland in the Mississippi Delta is irrigated with groundwater from the MRVAA, and the continual increase in irrigation over the past few decades has resulted in declining MRVAA groundwater levels in the central Delta. It is difficult and expensive to access groundwater in northeast Mississippi, so surface water is the main source of water for irrigation here. In both regions of the state, surface water is obtained from both nearby rivers and streams and by capturing runoff from precipitation and irrigation in on-farm water storage (OFWS) ponds. Although there are differences in how OFWS systems are constructed in the Mississippi Delta and the northeast region of the state, systems in both regions provide the dual benefit of providing water for irrigation and reducing nutrients flowing off-site and into other water bodies in the watershed. Thus, there is a need to quantify the use of these systems to better measure their benefits on a watershed scale. From 2007 to 2020, a geospatial inventory showed that 794.5 hectares of land have been converted to surface water storage in OFWS systems in the Big Sunflower River Watershed (HUC 08030207) in the Mississippi Delta. The inventory was conducted using aerial imagery from the National Agricultural Imagery Program (NAIP), which was acquired from the Mississippi Automated Resource Information System (MARIS) and the United States Department of Agriculture (USDA)—Natural Resources Conservation Service (NRCS) Geospatial Data Gateway. A similar geospatial inventory is in progress for northeast Mississippi.
Assessment of embankment damage due to wave impact in an on-farm reservoir
Year: Authors: Ozeren Y., Wren D., Rossell W.
On-farm reservoirs and tailwater recovery systems are commonly used conservation practices in the Mississippi Delta region to provide additional irrigation water and reduce demand on groundwater resources. Built above ground by using locally available soils, on-farm reservoirs are filled to capacity with spring rainfall and runoff and kept at full capacity as much as possible until growing season. Strong winds combined with high water levels during winter and spring months generate damaging waves which rapidly erode the earthen embankments, leading to additional maintenance costs for producers. The goal of this study was to assess embankment impairment due to wind generated waves in an on-farm reservoir near Shelby, MS. A wind station and two 2 m long self-logging wave staffs were installed to measure wind speed, wind direction and water level continuously during spring and summer months of 2021. The embankment geometry was monitored via land-based RTK surveys that were carried out during the same period. An attempt was made to quantify the rate of embankment impairment for the measured wind and wave characteristics. Key findings of the field study and comparison of field measurements with previous laboratory and field measurements will be presented.
Testing of a full-scale floating wave barrier for reducing wave erosion in a working irrigation reservoir
Year: Authors: Rossell W., Ozeren Y., Wren D.
In order to reduce the demand on groundwater resources, on-farm irrigation reservoirs are used for storing irrigation water in the Mississippi Delta region. The embankments surrounding these reservoirs are routinely damaged by wind-generated waves, resulting in high maintenance costs over time. It is thus necessary to identify cost-effective methods to protect the inner slopes of the embankments from wave action. Floating wave barriers (breakwaters) have been shown to reduce wave impact on offshore and coastal structures, and by identifying a simple, cost-effective design that maintains good efficacy, the use of a floating breakwater should reduce the frequency of required maintenance associated with the use of irrigation reservoirs. In this study, the use of floating pipe breakwater for reducing wave energy was investigated. Specifically, an efficient design for the cable system that holds the floating barriers in place was needed. The proposed breakwater uses common HDPE irrigation piping moored to the reservoir bottom by steel cables. A model floating breakwater was constructed and tested for various mooring configurations and a variety of wave characteristics in a wave tank at the USDA-ARS National Sedimentation Laboratory. Results of these experiments will be discussed in this presentation, as well as details of a full-scale floating pipe breakwater for deployment in a working irrigation reservoir.
Calibration and Validation of flow and water quality parameters using SWAT-CUP and LOADEST
Year: Authors: Nepal D., Parajuli P.B.
For the management of watersheds, hydrological models play an important role. To improve the accuracy of a hydrological model, calibration is performed. Validation helps to evaluate the improved accuracy of the calibrated model. However, sometimes, calibration is challenged by limited data availability. Measurement of water quality samples is done less frequently than flow because of high cost and limited resources availability. Therefore, it is necessary to estimate their loads/ concentrations during the periods of no measurements. The present study aims to 1) test regression model performances in predicting water quality loads 2) Soil and Water Assessment Tool (SWAT) calibration and validation of flow, total suspended solids (TSS), total nitrogen (TN) and total phosphorous (TP) at three monitoring stations at Big Sunflower River Watershed (BSRW). In this study we used Load Estimator (LOADEST) which has different regression models to predict water quality loads (during the period when flow data are available) to increase the number of data availability for calibration and to convert concentrations of TSS, TN and TP into loads since SWAT outputs TN and TP loads. Model evaluation was performed using R<sup>2</sup>, Nash-Sutcliff Efficiency (NSE) and Partial Load Ratio (PLR). The performance of LOADEST was found generally good in load prediction with a tendency towards overestimation in most of the cases (R<sup>2</sup>: 0.90-0.96, NSE: 0.50-0.95 and PLR: 0.84-1.17). The Sequential Uncertainty Fitting SUFI-2 algorithm inside SWAT-CUP was used for calibration and validation. The uncertainty analysis showed acceptable values of P and R factors for streamflow (p-factor: 0.72-0.87 and r-factor: 0.74-1.27) and TSS (p-factor: 0.56-0.89 and r-factor: 0.43-2.83). Model performance evaluation was performed using R2 and NSE. Model performed well for stream flow during both calibration and validation (R<sup>2</sup>: 0.60-0.86, NSE: 0.60-0.86). Similarly, performance evaluation for TSS indicated acceptable values (R<sup>2</sup>: 0.60-0.91, NSE: 0.38-0.91). The model evaluation statistics for TN and TP will be obtained further. The calibrated and validated model will then be used to simulate different Best Management Practice (BMP) scenarios. This study is believed to offer recommendations for successful multi-site and multi-variable calibration and validation to SWAT modelers under limited data availability.
Multi Criteria Decision Analysis (MCDA) for Mapping Watershed Erosion Potential
Year: Authors: Cartwright J.H.
Evaluating soil erosion is often assessed with traditional soil loss models like the Revised Universal Soil Loss Equation (RUSLE) and the Soil and Water Assessment Tool (SWAT). These models provide quantitative output for sediment yield and are often integrated with Geographic Information Systems (GIS). The work described here is focused on transitioning towards a qualitative assessment of erosion potential with Multi-Criteria Decision Analysis (MCDA) for improved decision support and management prioritization. The foundation of this work conceptually defined watershed erosion potential based on terrain slope, geomorphology, land cover, and soil erodibility. These criteria were evaluated with a weighted linear combination (WLC) model for generalized erosion potential. Expert input was added through MCDA with the Analytical Hierarchy Process (AHP). The AHP allows for experts to rank criteria, providing a quantitative metric (weight) for qualitative data. The individual AHP weights were altered in one percent increments to help identify areas of alignment or commonality. These areas were used to identify outliers and to develop an analysis mask for management area prioritization. The WLC, AHP, and SWAT output data were compared. There was some visual alignment between the WLC and AHP erosion potential output with the SWAT sediment yield output. The comparisons however were not a direct correlation between the data sets. General observations show similar results between the qualitative and quantitative erosion assessment approaches with alignment in the upper and lower ranks of erosion potential and sediment yield.
Development of the CCHE1D Looped Channel Network Model
Year: Authors: Zhang Y., Chao X., Al-Hamdan M., Bingner R., Vieira D.
The CCHE1D model, developed by National Center for Computational Hydroscience and Engineering (NCCHE), is designed for dendritic 1D channel networks to efficiently simulate unsteady flows with non-equilibrium and non-uniform sediment transport and channel morphological change, general pollutant transport and fate, nutrient dynamics and water temperatures. However, the dendritic channel network allows only one outlet and junctions of flow confluence, which is not applicable for more general and realistic cases that can be described only by looped channel networks with multiple outlets and junctions of both flow confluences and divergences, such as agricultural irrigations, natural river networks and urban floods. To expand its capabilities in handling looped channel networks, CCHE1D model needs new developments on the numerical solver and the generation tools for looped channel networks.<br><br> In this study, the junction-point water stage prediction and correction (JPWSPC) method proposed by Zhu et al. (2011) will be integrated into CCHE1D model to resolve the general 1D channel networks, either looped or dendritic. In JPWSPC, each branch is computed independently, which guarantees the simplicity, efficiency, and robustness of the numerical model. In addition to the digitization tool, the CCHE1D model plans to modify a delineation tool of dendritic channel network based on the watershed-merging algorithm (Zhang and Jia, 2020) for looped channel network generation. The observation that the loops only exit between junctions would make it possible to enable the watershed-merging algorithm for looped channel network generation. <br><br> This paper will present some preliminary results from selected test cases of looped channel networks to demonstrate the developments at the current stage for the CCHE1D looped channel network model. More results will be reported in the future.
Bamboo-char supported nano zero-valent iron (BC-nZVI) for water remediation
Year: Authors: Karunaratne T.
The use of nano zero-valent iron (nZVI) on water remediation applications have not been fully explored because of its agglomeration and rapid passivation. Biochar has been widely used to provide the stability to nZVI by preventing its agglomeration. Herein, a series of bamboo-char supported nZVI composites (BC-nZVI) are synthesized via a carbothermal reduction of iron salts using bamboo-char as a reduction source. BC-nZVI consists of nZVI particles with diameters ranging from 20 to 200 nm that are evenly distributed on the bamboo-char matrix. The effects of iron salt type (i.e., Fe(NO<sub>3</sub>)<sub>3</sub>, FeSO<sub>4</sub>, FeCl<sub>2</sub>, and FeCl<sub>3</sub>), carbothermal reduction temperature (600-1000 &8451;C), iron loading (5-40%) on the synthesized structure, morphology, and heavy metal (Cu<sup>2+</sup> and Pb<sup>2+</sup>) removal performance of BC-nZVI are evaluated. At the optimum condition (i.e., FeCl<sub>2</sub>, 15% iron loading, and 1000 &8451;C), the as-synthesized BC-nZVI exhibits high Langmuir adsorption capacities of 100.4, and 63.9 mg/g for Cu(II), and Pb(II) respectively. This study suggests that carbothermal reduction could be a promising route and a green alternative path of borohydride reduction for the production of BC-nZVI for water remediation.
In-situ conversion biomass to biochar-supported graphene-shelled zero-valent iron nanoparticles for heavy metals removal from water
Year: Authors: Zhang X., Karunaratne T., Zhang J.
Owe to the high reactivity and uptake capacity, zero-valent iron nanoparticles (nZVI) are a type of widely used engineering nanomaterial for heavy metal removal. However, nZVI suffers severe agglomeration and rapid passivation issues that impede its practical application for water remediation. Biochar, produced from biomass thermal conversion, has been recognized as a good carrier for nZVI to alleviate its aggregation issues. Herein, we report the in-situ synthesis of biochar supported graphene-shelled nZVI (BC-G@Fe0) through the carbonization of iron salt impregnated biomass. Biochar was served as the support material to prevent nZVI from aggregation, and graphene shell was served as the protecting agent to protect nZVI from rapid passivation. The structure and morphology of BC-G@Fe<sup>0</sup> are characterized by X-ray spectroscopies and electron microscopies. The performance of BC-G@Fe<sup>0</sup> for heavy metal removal was evaluated through batch adsorption experiments. The effects of carbonization condition and iron loading ratio on the formation of BC-G@Fe<sup>0</sup>, as well as heavy metal uptake capacities, were investigated. This study demonstrated a new type of nZVI sorbent, BC-G@Fe<sup>0</sup>, with enhanced dispersibility and stability for water remediation.
Resource recovery from dairy and municipal wastewater sources in a terracotta-biochar bioelectrochemical system
Year: Authors: Ghimire U., Gude V.G., Magbanua B.S.
Agricultural and municipal wastewater effluents contain valuable nutrients which can be recovered and recycled for agricultural applications. Microbial electrochemical systems facilitate recovery of nutrients from wastewater sources with concurrent electricity production. There is a strong potential for these systems; however, the electrode and membrane separator components of the process are still expensive. Moreover, for safe recovery and recycle of nutrients, natural and sustainable materials should be utilized. We explored the use of novel and sustainable materials for the construction of microbial electrochemical systems. Terracotta clay (an earthly material) and agricultural waste derived biochar materials were used to construct a microbial electrochemical system to enable nutrient capture and electricity generation from the organic substrates present in agricultural effluents. Municipal and agricultural (dairy production) wastewaters were evaluated for the potential resource recovery in the novel, sustainable microbial electrochemical systems. The effect of influencing parameters such as external resistance and COD concentrations on the performance of terracotta-biochar bioelectrochemical systems was studied. Appreciable levels of COD, N and P removals were observed. Moreover, power densities of 0.45 W/m<sup>3</sup> and 1.26 W/m<sup>3</sup> were recorded for synthetic municipal (500 mgCOD/L) and dairy wastewater (2500 mgCOD/L) sources, respectively. The SEM and EDX analysis results from this study confirm the beneficial use of sustainable materials for resource recovery applications in agricultural systems.
Evaluation of process parameters impacting energy-efficiency and emerging contaminant removal in membrane reactors
Year: Authors: Mark-Ige J., Gude V.G.
It is well known that activated sludge process is robust but energy intensive and offers only limited removal of micro pollutants and soluble microbial products. Advanced wastewater treatment processes such as membrane bioreactors are being increasingly adopted in wastewater treatment plants to address the discharge quality and environmental pollution issues. Aerobic (AeMBR) and Anaerobic Membrane Bioreactors (AnMBR) are an essential part of the advanced wastewater treatment options, which offer advantages in terms of lower effluent discharge and smaller footprints over the traditional wastewater treatment plants. The key driver for anaerobic membrane bioreactors (AnMBRs) for municipal treatment is enabling the transition to energy neutral wastewater treatment (Wang et al., 2018). However, membrane fouling is a major drawback to utilization of MBRs. This study examines data reported in literature and analyzes correlations between wastewater characteristics and various operational parameters such as Mixed Liquor Suspended Solids (MLSS), Hydraulic Retention Time (HRT), Solid Retention Time (SRT), Temperature (T), Biogas production, Transmembrane Pressure (TMP), and Chemical Oxygen Demand (COD) against Methane production (CH4), Membrane Fouling, Soluble Microbial Products (SMP), and Extracellular Polymeric Substrate (EPS). These external and internal are the major factors attributed to fouling of the MBRs. Preliminary data analysis indicates that the strength of the influent COD has a major influence on methane production. This presentation will include a detailed analysis of influencing factors and recommendations for improving the membrane reactor performance to accomplish energy-neutral or energy-positive and superior wastewater treatment.
Graphene Sand Composites and Their Applications in Water Treatment
Year: Authors: Nusair A., Alkhateb H., D'Alessio M.
Water scarcity and the occurrence of chemicals of emerging concern (CECs) are making the world in need of safe and renewable water resources. Slow sand filtration (SSF) represents an affordable but effective method to filter water. However, SSF has a few weaknesses such as clogging and the inability to effectively remove CECs. The goal of this study was to investigate the ability of graphene-coated sand to overcompensate these limitation. Three types of sand, Ottawa, concrete, and masonry, were used. Graphine-coated sand was obtained using a reduction method to transform a coating of sugar into elemental carbon in N2 atmosphere at temperatures reaching 750℃ followed by activation with sulfuric acid. Vertical flow-through columns were used to evaluate the ability of the different materials to remove turbidity and bacteria. Due to the additional expense related to the activation process, columns packed with graphene-coated sands were tested alongside the non-activated ones as well as columns containing the raw sands. A digital microscope as well as Raman spectroscopy, scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy were implemented to verify the effectiveness of the coating process.<br><br> The digital microscope revealed that rounded (Ottawa sand) particles were coated less efficiently than sub-angular and angular particles (concrete and masonry sand). The Raman spectroscopy revealed the formation of G and D bands in all three graphitized sands suggesting complete graphitization of the sugar and the presence of defect site necessary for the adsorption of contaminants. Furthermore, the peak intensity was 30% higher in concrete and masonry graphitized sands compared to Ottawa graphitized sand. SEM revealed the formation of carbon sheets 10 nm thick and EDS results backed up the geological identification of the sands with quantification of the elements. In the presence of high turbidity (average: 250 NTU), graphene-coated Ottawa sand, not only achieved higher turbidity removal than the raw Ottawa sand but also experienced less severe clogging. Higher bacterial removal was achieved with graphene-coated sands, in particular Ottawa and masonry, compared to the corresponding non-coated sands.
Machine Learning Based High Resolution Soil Moisture Estimation from Small UAS utilizing Signals of Opportunity
Year: Authors: Senyurek V., Farhad M.M., Gurbuz A.C., Kurum M.
Soil moisture (SM) is one of the essential factors for agricultural science and related studies. Low or saturated SM negatively affects crop growth. Traditionally SM content is measured in-situ using SM probes. Although in-situ measurements provide accurate and high temporal SM information in a single point, it is costly, inefficient, and time-consuming for high spatial resolution. Spaceborne remote sensing platforms are practical for a global scale. However, their low spatial resolution (10-40 km) and low temporal resolution (2-3 days) are too coarse for many site-specific precision agriculture applications. <br><br> This study proposes a low-cost and practical technique based on Global Navigation Satellite Systems-reflectometry (GNSS-R) utilizing a small drone. A random forest machine algorithm is used to develop an SM estimation model that uses reflected GPS signals, vegetation indices from a multispectral camera, and crop size information from LIDAR as input features. The field experiment was conducted on a 2.48 ha corn and cotton field at MSU's heavily instrumented North Farm. The needed data for the machine learning model was acquired from April to October 2021.<br><br> The study results showed that the 2.48 ha field could be covered by GPS reflectometry with about 12 mins flight time, and SM can be mapped with 5m x 5m spatial resolution with high accuracy. We will present the data collection, machine learning based soil moisture estimation approach and the obtained results over the test area.
MS Phosphorus Index: Can it adequately guide nutrient management plans in the Mississippi Delta?
Year: Authors: Fernandez-Martinez F., Rodriguez L.S., Ramirez Avila J.J., Locke M., Achury S.O., Oldham L.
Agricultural nutrient runoff from fields in the Mississippi (MS) Delta contribute to surface and groundwater quality impairment in the region. The phosphorus (P) indices are tools widely used to assess the vulnerability of agricultural fields to P loss and support nutrient management strategies. The objective of this study was to identify the impact of each MS P-Index input on the assessment of P loss vulnerability for sites in the MS Delta. The probability distribution of the different input parameters (i.e. soil erosion rate, soil test P, P application rate, P fertilization source and method, and runoff class) was determined by using historical crop management data from Stoneville and Beasley Lake watershed, various USDA web tools, and GIS data for the region. Monte Carlo simulations (10,000 iterations) were generated to evaluate the existing MS P-Index and a version in which the model inputs are unweighted. Simulations showed that the distance to water, followed by the organic P<sub>2</sub>O<sub>5</sub> application method were the parameters that most affected the P-Index score, while the inorganic P<sub>2</sub>O<sub>5</sub> application rate was the least sensitive parameter. Stepwise regression showed that 87% of the variance of the P-Index scores was explained by five input parameters (distance to water, organic P<sub>2</sub>O<sub>5</sub> application rate and method, inorganic P<sub>2</sub>O<sub>5</sub> application method, and soil erosion), while all eight input parameters explained 89% of the variance. The mean P-Index scores derived from the simulations were 2.49 and 3.16 for the general and unweighted models, respectively, scoring a low P loss vulnerability in 94% and 83% of the cases, respectively. Since the outputs of this tool are not consistent with the reported issues related to nutrient leakage from agricultural watersheds in the region, results indicate the need for a more in-depth analysis of the MS P-Index and its ability to represent P-loss vulnerability of fields in the MS Delta. An adequate calibration and validation process with analyses of water quality are needed for further research and improvement of the MS P-index tool.
Advances in Groundwater Modeling for the Mississippi Delta from the Mississippi Alluvial Plain (MAP) Project
Year: Authors: Duncan L.L., Haugh C.J.
The goal of the regional groundwater availability study of the Mississippi Alluvial Plain (MAP) is to improve estimates of water availability, both past and present, and to determine how groundwater resources will respond to current and future stresses. Groundwater withdrawals from the Mississippi River Valley alluvial aquifer within the Mississippi Delta have been vital for agricultural production. Despite the apparent stabilization of groundwater levels in some places across the Mississippi Delta following several recent years with above-average rainfall, long term sustainability of the aquifer remains a concern due to the large groundwater-level declines over the last century, increasing demand for irrigation from groundwater, and uncertainty about future climate.<br><br> The MAP study builds upon the previously developed Mississippi Embayment Regional Aquifer Study (MERAS). The Mississippi Delta inset groundwater flow model offers several enhancements over older versions of the regional groundwater flow model, including higher spatial, vertical, and temporal resolutions. The inset model uses the newer MODFLOW 6 and PEST++-IES modeling and parameter estimation technology, providing more robust calibration. The inset model incorporates information from airborne electromagnetic surveys through a new surficial aquifer base, updated confining unit thickness, and zoned parameterization of aquifer properties. The inset model also uses Soil-Water-Balance model estimates for recharge and runoff estimates, agricultural water use estimates partially derived from the Mississippi Department of Environmental Quality voluntary metering program, and a denser streamflow routing network.<br><br> Accurate assessments of water availability in the Delta are critical to informing management decisions, establishing best practices for water use, and contending with projected changes to the regional water cycle. The groundwater response to different combinations of water management practices and anticipated changes in water budget components is examined using the groundwater model. This study is intended to provide improved estimates of historical, current, and future groundwater availability and to aid water resource managers in making decisions that can help sustain agricultural and industrial practices in the MAP region using a numerical groundwater model.
Model performance and uncertainty analysis of APEX for hydrologic predictions in the Mississippi Delta region
Year: Authors: Mendez J., Ramirez Avila J.J., Locke M.
An uncertainty analysis assesses the effects of knowledge gaps with respect to understanding the model output and performance. In order to study the impact of using different weather stations and soil conditions (inputs) on model outputs, the Agricultural Policy/Environmental Extender (APEX) model was used to predict runoff from agricultural fields in the Mississippi Delta. Two scenarios were proposed: (i) varying climate inputs from five stations located within a radius of 40-km from the study site (Minter at 37.8km-N, Greenwood at 15.9km-NE, Belzoni at 36km-SW, Lexington 37km-SE, and Moorhead at 25km-W); and (ii) assuming a homogeneous soil type in the fields from the actual four soil series present in the study site. An APEX model (v.1501) was calibrated and validated using four years (1996 to 1999) of available information for runoff, water quality, soil characteristics and in-situ climate dataset from two fields (DH1-18ha and DH2-12ha) within the Deep Hollow Watershed (DH) in Leflore county, MS. The APEX baseline scenario used the actual soil series distribution in the fields (Alligator, Dubbs, Dundee and Tensas) and climate information collected in-situ. For all the scenarios, APEX model performance of runoff predictions was assessed using three objective functions: Nash Sutcliffe Efficiency (NSE), percentage of bias (PBIAS), and Kling-Gupta efficiency (KGE). The baseline scenario yielded satisfactory results in the prediction of monthly runoff with NSE values of 0.67 and 0.90; PBIAS values of 29% and 21%; and KGE values of 0.61 and 0.73 for DH1 and DH2, respectively. For the DH2 field, APEX runoff predictions were only satisfactory when using information from the nearest weather station to the study site (Greenwood). For DH1 the same station yielded a better performance than the other three stations, but none yielded satisfactory. For both fields the use of the Greenwood dataset represented an underestimation of runoff. When assuming a homogeneous soil series for the entire fields' area, the use of the Alligator and Tensas soil series (silty clayly and clayly soils with hydrologic groups C and D, respectively) improved the APEX runoff estimations and performance. When assuming the soil series Dubbs and Dundee (very fine sandy loam and loamy with hydrologic groups C and B, respectively) runoff underestimation increased with respect to the baseline. Overall, results offer valuable information to modelers of watershed in the Mississippi Delta, in their decision-making regarding model setup and output interpretation for areas with limited climate and soil information.
Prediction of Groundwater Level Lag Times Using Spectral and Trend Analyses: Implications for Water Management and Drought Assessment
Year: Authors: Guthrie G.M., Jin G.
Groundwater data is commonly used by state and federal organizations as a component of drought assessment during dry seasons. The incorporation of this data in monthly assessments may be of limited usefulness due to the delayed response, or lag time, of water levels to precipitation events resulting from the time required for recharge waters to migrate to the saturated zone. Daily water-level measurements are traditionally presented as time series hydrographs that are seemingly complex, noisy, and thus difficult to interpret due to diurnal, seasonal, and even decadal variations. Continuous water level (WL) data from eight drought monitoring wells in different hydrogeologic provinces and precipitation (PPT) data from nearby stations have been analyzed using spectral analysis by discrete Fourier transform to evaluate primary seasonal and trend events. The technique can reveal both the periods and magnitudes of all seasonal, cyclical, and/or long-term (more than one year) wet and drought events and provide important parameters to decompose time series data into seasonal, trend, and random components using seasonal and trend decomposition. The resulting trend components are then evaluated with correlation analysis to establish groundwater lag time in the wells in response to precipitation events. Lag time is determined from cross-correlation diagrams as the amount of time shift required to attain a peak correlation coefficient for both WL and PPT trend curves. Lag time is not consistent among wells, ranging from 60 to 180 days, and the differences may reflect different environmental and hydrological properties of the wells, such as elevation, confining conditions, distance from recharge area, permeability, hydraulic conductivity, unsaturated zone hydraulic properties. Lag time analysis provides an invaluable tool to accurately model/forecast groundwater changes using machine learning and statistical techniques and the ability to predict anticipated groundwater levels at the beginning of the drought season. Using this methodology will be an invaluable tool for water managers and stakeholders to assess potential water availability issues.
Does improving soil health benefits water quality in the Mississippi Delta?
Year: Authors: Sarmiento-Rodriguez L.A., Ramirez Avila J.J., Locke M., Singh G., Achury S.O.
Research has shown that enhancing soil health improves crops productivity and benefits water quality. A study was established to determine whether differences in soil health, associated with different soil management practices, could have a positive effect on runoff water quality from agricultural fields in the Mississippi Delta. The soil quality/health indices for plots/fields with different management scenarios in two different locations of the Mississippi Delta, are to be correlated with runoff water quality concentrations and loads. The soil health/quality index for the study fields/plots was determined using the Soil Management Assessment Framework (SMAF). Study fields/plots were planted with irrigated soybean and corn under different cover crop residue scenarios in 2021. Six indicators were selected to contrast the potential impact of management practices: aggregate stability, soil organic carbon, pH, soil test phosphorus, bulk density and soil test potassium. Irrigation runoff samples were collected from corn and soybean plots to determine concentrations and loads of total phosphorus, nitrate—nitrogen (NO3-N), total Kjeldhal nitrogen, total nitrogen, total suspended solids, salinity, pH, and turbidity. This presentation will show preliminary results of the study as well as further steps towards the completion of a sensitivity analysis of the SMAF tool.
Soil physical responses from integrating conservation agriculture and implications on water quality in the Mississippi Alluvial Valley
Year: Authors: Firth A., Brooks J., Locke M., Morin D., Brown A., Baker B.
Agriculture is the greatest contributor to overall consumptive water use with deleterious effects seen in river depletion and groundwater over draft. Despite negative documented effects of agricultural land use (i.e. soil erosion, compaction, nutrient runoff) on critical natural resources (i.e. water), food production must increase in order to meet the demands of a rising human population. Given the environmental and agricultural productivity concerns of intensely managed soils, there is a growing interest in conservation practices that mitigate the negative effects of crop production and enhance environmental integrity. In the Mississippi Alluvial Valley (MAV) region of Mississippi, USA, the adoption of cover crop (CC) and no-till (NT) management practices has been low because of a lack of research specific to the regional nuisances. Therefore, this study assed the long-term soil physical responses from integrating CC and NT management to agricultural soils in the MAV region of Mississippi. It was hypothesized that the combination of a diverse CC mixture and NT management would provide more favorable soil physical properties compared with single CC mixtures or tillage treatments. Bulk density, aggregate stability, water holding capacity and water infiltration were measured after 5 years of CC and NT treatments. Data on soil properties were subjected to analysis of variance to assess the effects of tillage, CC and time on soil physical response (bulk density, aggregate stability, moisture retention, moisture porosity, water infiltration). Generalized linear mixed models were used to determine how dependent variables interact with independent treatments. Bulk density was found to be significantly lower in NT plots and aggregate stability was greatest in plots with a single CC species (elbon rye) as a CC. No differences were found in water infiltration; however, data collection may not have used optimal methods. Water porosity was greatest in a NT-CC combination, suggesting that conservation agriculture can improve soil physical characteristics that are linked with decreased water runoff.
Status and Trends of Total Nitrogen and Total Phosphorus Concentrations, Loads, and Yields in Streams of Mississippi, Water Years 2008-18
Year: Authors: Hicks M.B.
To assess the status and trends of nutrient conditions of surface waters throughout Mississippi, the U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, summarized concentrations and estimated loads, yields, trends of total nitrogen (TN) and total phosphorus (TP) between 2008 and 2018 water years for 22 streams in Mississippi.<br><br> Relation of streamflow to concentrations of TN and TP varied among sites and were generally related to land use: sites with high agriculture land use in the drainage basin generally had positive correlations between streamflow and nutrient concentration, suggesting influence of event-driven nonpoint-source runoff; sites near urban (developed) areas generally had negative correlations, suggesting chronic point-source influences during low-flow conditions; sites with high forest land use and lower agriculture and urban land use had little to no association between streamflow and concentration.<br><br> Seasonal distributions of concentrations of TN and TP also corresponded closely with differences in land use among sites. Sites near urban (developed) land had the highest nutrient concentrations in late summer and fall, whereas nutrients were highest during the spring among sites with a high percentage of agricultural land. However, seasonal patterns in nutrient concentrations were not apparent among sites that were primarily forested or with little developed land<br><br> Trend analyses of TN loads between 2008 and 2018 water years indicated that eight sites had statistical likelihoods for upward trends of TN loads, seven sites had statistical likelihoods for downward trends, and six sites had no statistical trend. Trend analyses of loads of TP resulted in 16 sites with upward trends, 3 sites with downward trends, and 2 sites considered "about as likely as not."<br><br> Results of estimated nutrient yields calculated for sites across MS in this study varied in consistency compared to predicted regional-scale nutrient yields generated by 2012 SPAtially Referenced Regressions on Watershed attributes (SPARROW) model. Notably, yields of TN and TP at four sites in the highly agricultural area of northwest Mississippi (Delta) were underestimated by SPARROW model by an average of 25 percent and 44 percent, respectively. <br><br> Overall, data indicate yields of TN may have slightly decreased over the last 20-30 years, but TP yields remain constant or are increasing and SPARROW model estimates for Mississippi streams may be improved with additional calibration sites and data, especially in the Delta.
Impact of Bonnet Carrè Spillway openings on coastal wetland plant productivity utilizing remote sensing imagery
Year: Authors: Feldpausch K., Wu W.
Wetlands are highly productive ecosystems that provide important ecosystem services. However,they have been threatened by extreme hydrological events, such as diversions of freshwater, droughts, and accelerated sea-level rise through change of inundation and salinity regimes. This study evaluated how diversions of freshwater, particularly Bonnet Carrè Spillway openings in 2019, affected vegetation productivity in salt marshes on the Mississippi Gulf Coast, US. The Bonnet Carrè Spillway was built to prevent and mitigate flooding in New Orleans. The frequency of its opening has increased over the last two decades, and 2019 was marked the first time in history that this spillway was opened in two consecutive years and twice in one year.<br><br> We first developed a model to link vegetation green biomass to spectral information of Landsat and Sentinel satellite images, and then applied the model to hindcast vegetation green biomass based on the historical images before and after the openings of the Bonnet Carrè Spillway to assess the openings' impact on vegetation. My study area is two estuarine systems that differ in their proximity to the Bonnet Carrè Spillway, elevation, salinity, nutrient levels, including Hancock County Marshes on the west, and Grand Bay National Estuarine Research Reserve on the east in Mississippi. We found marginal short-term impact. Future studies should focus on long-term impact of these extreme events on salt marshes. This study improves our understanding of vegetation and blue carbon dynamics in highly productive salt marsh ecosystems. It also informs the unexpected consequences of anthropogenic activities on valuable ecosystems.
Exploring circular economy concept of repurposing spent bioelectrochemical system materials for reuse in agricultural applications
Year: Authors: Sauers J., Band D., Ghimire U., Reddy K.R., Magbanua B., Gude V.G.
Circular economy concept (CEC) has been introduced to promote sustainability of current resource utilization and waste management practices. The concept can be loosely defined as an economic system that aims to accomplish sustainable development and economic prosperity by moving away from the "end-of-life" concept. CEC looks to repurpose, recover, reduce, and recycle materials in production and consumption processes. An interesting investigation using CEC is crushing expended bioelectrochemical treatment systems (BES) made from natural materials of bentonite, terracotta, and biochar, that were treated with synthetic municipal wastewater (SWW) and synthetic dairy wastewater (DWW) to create soil amendments to promote plant growth. The BES were constructed for nutrient capture from the SWW and DWW. Soil amendments benefit plant growth by providing more nutrients to the soil. This investigation follows how well 60 corn plants can grow in four different soil amendments. The four-soil amendment were biochar amended soil (BS), terracotta amended soil (TS), terracotta - biochar from SWW-BES amended soil (SWWS) and terracotta - biochar from DWW-BES amended soil (DWWS). Each soil amendments accounted for 10% of the growing medium. The corn was treated with three different nutrient treatments (100% Hoagland nutrition solution, 50% Hoagland nutrition solution, and 0% Hoagland nutrition solution). A control soil consisting of no amendments was used as the reference condition. Each soil amendment and control soil had a total of 12 plants, each of which was subdivided into the three nutrient treatments (4 plants per nutrient treatment). The investigation took place over 38 days at the Soil-Plant-Atmosphere Research Unit at Mississippi State University. The plants were harvested on day 38 and were analyzed for plant height, leaf number, leaf area, leaf dry weight, stem dry weight, root dry weight, shoot dry weight, total dry weight, root/shoot ratio, root length, root surface area, root volume, chlorophyll, flavonoids, nitrogen balance index, stomata conductance, transpiration, and plant tissue. The soil was tested for texture and nutrient analysis. Further, plant tissue was also analyzed. The results and some preliminary conclusions of this on-going investigation will be discussed in this research presentation.
Terracotta as a natural adsorbent for nutrient recovery from agricultural effluents
Year: Authors: Sauers J., Gude V.G.
Nutrients released through agricultural effluents cause eutrophication of receiving water bodies. In this research, the adsorption capacity of terracotta clay was evaluated due to its promising benefits in nutrient and water retention. The efficacy of terracotta clay to act as a solid-phase sorbent was studied for two main nutrients, nitrogen and phosphorus. The phosphate solutions were prepared at three difference concentrations (20 mg/L, 35 mg/L, and 50 mg/L). The phosphate solutions were mixed with the terracotta clay in a mixer at 8 different time intervals of 0, 5, 10, 20, 40, 60, 300, and 1440 minutes at 25℃ and 50℃. Samples were collected at the aforementioned predetermined intervals. The ammonium nitrogen solution was prepared in a similar manner to the phosphate solution, but only tested at a concentration of 50 mg/L at 25℃. <br><br>The kinetics of nutrient absorbance by the terracotta clay was studied by fitting the Pseudo-first-order, pseudo-second-order models. The adsorption capacity for the phosphate was similar at both temperatures for ammonium. The terracotta clay absorbed the phosphate for the first 20 minutes followed by desorption at the 40-minute interval. The phosphate absorbance capacity was better at 25℃ than 50℃. The pseudo-second order model fitted the adsorption kinetic data with high correlations. The R<sup>2</sup> values for the three concentrations range from 0.9765 to 0.9977 at 25℃, while the confidence intervals for the three concentrations at 50℃ ranged from 0.9672 to 0.9952. The phosphate adsorption capacity at a temperature of 50℃ but the capacity varied at each time interval. This presentation will also include thermodynamic analysis of the adsorption studies.
The University of Mississippi Lead in Drinking Water Project
Year: Authors: Otts S., Green J.J., Surbeck C., Willett K.L.
Childhood lead poisoning is a challenging social issue that requires the coordination of health, housing, and environmental law and policy. Little is known about the contribution of lead pipes and water treatment to lead poisoning in Mississippi. The University of Mississippi Lead in Drinking Water Project (UM Lead Project) launched in 2017 and is headed by an interdisciplinary team of researchers from the University of Mississippi (Stephanie Otts, J.D.; Dr. Cristiane Surbeck; and Dr. Kristie Willett) and the Southern Rural Development Center (Dr. John Green). The team takes a community-engaged, research-based approach to address lead in water-related health gaps in the state. To date, the Team has organized almost twenty lead education and sampling events, tested drinking water for more than 300 families, presented annually at the Mississippi Water Resources Conference, taught an Honors College Experiential Course, established a referral program with the Mississippi State Department of Health (MSDH), partnered with Mississippi State Extension's SipSafe program to sample water at childcare facilities for lead, and published two academic journal articles. Our research has revealed that lead in drinking water is an issue of statewide concern, especially for Mississippians who obtain their drinking water from private wells. In 2021, the UM Lead Project received funding from the University of Mississippi to organize and host a statewide lead forum in October 2022. This presentation will provide an overview of the UM Lead Project's work and research findings, as well as provide an opportunity for conference participants to provide input into the planning of the Lead Forum.
Occurrence and Characteristics of Microplastics in Wastewater Treatment in Oxford, Mississippi
Year: Authors: Gao Z., Cizdziel J.
Microplastics (MPs) are a diverse suite of contaminants commonly found in wastewater. However, wastewater treatment plants (WWTPs) were not designed to remove MPs. Further, MP pollution has not been examined in wastewater stabilization ponds (WSPs), which serve rural and small communities worldwide, and in WWTPs that serve universities where sudden and drastic changes in on-campus populations occur. Here, we characterized MPs (~45 μm-5 mm) in a WSP serving ~500 houses and in an adjacent lake as well as in a modern oxidation ditch WWTP at the University of Mississippi. In the pond, putative MPs were most abundant in duckweed (<em>Lemna minor</em>) and sludge (75 ± 22 and 12.8 ±3.1 particles/g, respectively: ±1 standard deviation (SD), n = 6, dry weight). In the water, average concentrations (particles/L ± 1 SD, n = 6) were highest in the WSP (4.1 ± 0.6), followed by WSP effluent (3.9 ± 0.5) and the lake (2.6 ± 0.6). Over 20 types of MPs were identified, with the distribution varying somewhat between the water, sludge, and duckweed. Polyester and polyethylene were the predominant types, followed by polyethylene terephthalate, polyacrylate, PVC, and polystyrene. Morphologies consisted of fibers (62-71%), fragments (28-37%), and beads (1-6%). High-density polymers were more frequently found in sludge. Potential sources include synthetic textiles from laundry and plastics washed down household drains. Overall, with ~786,000 MPs/day released from the pond and with duckweed a source of food for waterflow, we demonstrate that WSPs can be point sources of MPs to both aquatic and terrestrial ecosystems. At the University WWTP, we observed the highest abundance of MPs after a football game (62.3 ± 7.6 particles/L, average ± 1SD, n=3), followed by 46.3 ± 9.5 particles/L sampled the prior week, and 22.8 ± 4.5 particles/L during a period with little on-campus activity. Over 90% of the MPs were removed in the primary treatment. MPs were most abundant in the oxidation ditch biological unit (1962 particles/L) as the MPs accumulate in the activated sludge. Concentrations of MPs in secondary clarifier and final effluent were <4 particles/L during higher-flow periods and between 16-39 particles/L during lower flow periods. MPs were mainly composed of polyester, acrylic paint, PVC, polyethylene, polypropylene and polyurethane. Most MPs in the effluent were fibers (61%), fragments (21%), and films (13%), with beads and foams contributing the rest (5%).
A Geospatial Methodology for Mapping Land Parcels with Individual On-Site Wastewater Disposal Systems
Year: Authors: Cartwright J., Grala K., Collini R.
Individual on-site wastewater disposal systems (IOWDS) or septic systems are an ever-increasing source of non-point source pollution along the coast of Mississippi. Inventories of these systems are not always complete or simply non-existent. This project utilized geospatial technologies, specifically geographic information systems (GIS), to identify land parcels that are potentially using an IOWSD. The approach used existing service utility provider records, land parcels, and improvement values to identify properties that are likely to have on-site waste disposal for a specific service area. The methodology was developed around geocoding techniques coupled with multi-criteria selection for property identification. The project area had a total of 83,863 parcels and 22,976 were identified as non-serviced parcels. Using a threshold improvement value of $7,500 resulted in 9,550 parcels that potentially have an IOWDS. These identified parcels were assessed for vulnerabilities based on groundwater depth, high-tide flooding for current and future sea level rise, and current and future storm surge under future sea level rise scenarios. 6,232 (65%) of these were found to be at some level of risk over the next several decades due to changes in groundwater, high tide, and/or storm surge as seas rise. Additional spatial analyses were performed and identified 1,621 parcels were near existing infrastructure to help prioritize transitioning from on-site disposal to a service utility.
Evaluation of water quantity and quality of coastal watersheds of Mississippi
Year: Authors: Bhattarai S., Parajuli P., To F.
The unique interface of coastal waters lying between ocean and terrestrial land serves as a critical habitat to many shellfish species and it supports a wide range of human activities. This study evaluates the quantity and water quality of water runoff from the coastal watersheds in Southeastern Mississippi into the Bay of Saint Louis. A process-based river-basin scale Soil and Water Assessment Tool (SWAT) model is applied to integrate current scenarios of different management practices implemented into the upland watersheds which are predominated by forests. Two adjacent watersheds namely, Wolf River Watershed and Jourdan River Watershed are studied independently, the developed model is calibrated and validated for the flow, sediment, and nutrient yield using data collected from USGS 02481510 and USGS 02481660 stations for each watershed. Statistical analysis of the developed SWAT model includes coefficient of determination (R2) and Nash-Sutcliffe Efficiency (NSE), and the model's prediction was evaluated. Quantifying the amount of sediment yield and nutrient loss from small coastal watersheds flowing into St. Louis Bay will be insightful in assessing the impacts of water pollution in the bay ecosystem.
Biogeochemical Impacts of Altered Freshwater Flow to the Mississippi Sound
Year: Authors: Dillon K.S., Milroy S.P., Shiller A.M., Gilbert M.
The Bonnet Carrè Spillway (BCS) is a flood control structure on the lower Mississippi River that is periodically opened at peak flow to prevent flooding in New Orleans and other municipalities. Since its construction in 1931, the spillway has only been opened fourteen times. However, in recent years, spillway openings have become more common with four openings since 2016. In 2019, the BCS was opened twice for a combined total of 123 days, sending large amounts of Mississippi River water into the Mississippi Sound resulting in large reductions in salinity, extensive algal blooms and nearly 100% mortality of oyster reefs. Weekly water quality assessments were conducted from June thru August 2019 to measure nutrients, dissolved organic carbon and nitrogen, chlorophyll a, and particulate organic matter as well as the stable isotopic composition of water (δ18O and δD) for water source tracking. River water had high nitrate concentrations (92 μM) and low ammonium and soluble reactive phosphate (SRP) concentrations (<2 μM). Water isotope results show that water from some regions of the Sound was composed of nearly 50% Mississippi River water. Dissolved inorganic nitrogen (DIN) and chlorophyll concentrations increased by an order of magnitude compared to historical measurements and bottom water hypoxia was measured across large portions of the Sound when bottom water salinity was greater than 12 psu. Bottom water ammonium and phosphate concentrations were elevated at when DO was low (< 4 mg/L) due to anaerobic mineralization of organic matter, dissimilatory nitrate reduction to ammonium or a combination of the two processes however diffusion of these nutrients from sediments cannot be ruled out with the available data. After the BCS closure in late July, nutrient concentrations throughout the Sound returned to low background concentrations within several weeks.
Development of a preliminary metric-based indicator of functional recovery for tidal marshes
Year: Authors: Dybiec J.M., Ledford T., Rinehart S., Tatariw C., Mortazavi B., Cherry J.
Despite their known importance, an estimated 25-50% of tidal marshes have been lost worldwide over the past 50 years due to anthropogenic pressures, such as coastal development and pollution, and those that remain are at increased risk of loss due to climate change. While tidal marsh restoration and creation efforts are used to offset these losses, post restoration/creation monitoring typically focuses primarily on the recovery of plant communities. As a result, the recovery of important functions like carbon storage and nitrogen removal capacity, both of which are of great ecological and societal importance, is often not assessed. Therefore, an accessible method for estimating functional recovery in restored and created tidal marshes would be of great benefit to coastal sustainability efforts. Metric-based indicators have previously been used to assess ecosystem functions through simple and inexpensive biotic/abiotic measures, and therefore, may provide a useful method to assess restoration in a time-effective and budget-friendly manner. <br><br> Using data collected from 12 restored/created and 4 natural tidal marshes across the Mississippi-Alabama Gulf Coast during Summer 2021, we calculated percent recovery of certain functions at restored/created marshes by pairing them with reference natural marshes. We then used backwards model selection to determine what combination of simple site characteristics (e.g., soil bulk density, percent plant cover, site age) could explain the recovery of more complex functions (e.g., soil organic matter accumulation, above/belowground biomass). For example, we found that soil organic matter recovery could be estimated through site age and bulk density, while plant biomass recovery could be estimated by site age and percent plant cover. From these relationships, we generated metrics capable of "scoring" functional recovery in tidal marshes based on these easier-to-measure factors. Further data collection in Summer 2022 will allow us to assess the validity of this indicator of functional recovery. While preliminary in nature, this model represents a unique and accessible method for improving post-restoration/creation monitoring efforts.
Mississippi River Valley alluvial aquifer groundwater ages from lumped parameter models fit to measured tracer concentrations
Year: Authors: Gratzer II M.C., Knierim K.J., Solder J.E., Kingsbury J.A., O'Reilly A.M.
Lumped parameter models (LPM) were used to estimate groundwater ages from age tracer concentrations in samples collected from 89 wells in the Mississippi River Valley alluvial aquifer (MRVA) and Mississippi Embayment aquifer system (MEAS). The type of LPM for each well was chosen based on confinement, likely sources of water, and observed age-tracer concentrations. Ages for 47 MRVA wells were estimated with LPMs representing unconfined conditions, and ages for 25 MRVA and all 17 MEAS wells were estimated with LPMs representing confined conditions. Ages for 55 MRVA wells and 14 MEAS wells were estimated with LPMs representative of distributed recharge (as opposed to localized recharge) within the areal extent of the MRVA. Age dates for 17 MRVA wells and 3 MEAS wells were modeled as binary mixtures of distributed recharge and localized recharge or water from an adjacent aquifer. Mean ages of MRVA samples (n=72) range from 12 to 24,000 years, with more than 70% of the ages being less than 830 years. Mean ages of MEAS samples (n=17) range from 350 to >50,000 years, with more than 70% of the ages being greater than 8,800 years. This presentation will discuss relations between estimated ages and various types of related hydrologic data, including water chemistry data, airborne electromagnetic resistivity surveys of the Mississippi Alluvial Plain, and numerically modeled groundwater flow paths. Improved knowledge of the distribution of groundwater age in the MRVA will refine groundwater flow models and improve understanding of groundwater chemical evolution in the aquifer, ultimately helping water resource managers decide how best to use and protect one of the most heavily used aquifers in the United States.
Numerical Simulation of Fate and Transport of Chemical Contaminants in Dan River Due to Coal Ash Spill Accident
Year: Authors: Chao X., Zhang Y., Al-Hamdan M.
Large quantities of stored coal ash nationwide pose a serious threat to the environment and wildlife when accidently released into surface water systems. On February 2, 2014, the failure of a storm water pipe under the primary coal ash pond of the Dan River Steam Station owned by the Duke Energy released about 39,000 tons of coal ash and 27 million gallons of pond water into the Dan River near Eden, N.C., about 130 miles upstream of the Kerr Reservoir. Together with the coal ash, a number of contaminants attached to the particles and dissolved in the pond water were also released into Dan River. <br><br> Numerical model is an effective tool to simulate the transport processes of coal ash and associated chemical contaminants in river flow. In this case, the entire study reach of the river-reservoir system extends from the USGS Wentworth gauge on Dan River, about 22 km upstream of the spill location to the Kerr Dam, about 182 km downstream of the spill location. For such a long river-reservoir system, the CCHE1D model developed by National Center for Computational Hydroscience and Engineering at the University of Mississippi was applied to simulate the fate and transport of contaminants due to the Dan River coal ash spill accident. The processes of advection, diffusion, sedimentation, and adsorption/desorption of contaminants were considered in the model. Several chemical contaminants, including arsenic (As), mercury (Hg), and selenium (Se) were simulated, and their concentration distributions in water column and bed sediment were obtained. The simulated results were validated using the measured data obtained from EPA. Those results provide useful information for water environment evaluation and water resource management.
Can short rotation woody bioenergy crops improve shallow groundwater quality in the Lower Mississippi Alluvial Valley?
Year: Authors: Kyaw T.Y., Siegert C., Renninger H.
In the Lower Mississippi Alluvial Valley (LMAV), agricultural runoff is a critical environmental problem because it degrades the water quality. Although the LMAV is a pivotal region for agricultural production, there are also areas of marginalized land where row crop production is less profitable due to experiencing seasonal waterlogging and high water tables. Consequently, these marginal lands are usually left unmanaged. However, establishing short rotations woody crops (SRWCs) on these floodplains can be beneficial to land owners because the climatic, agricultural, and infrastructural systems of the LMAV have the potential for developing a biomass-based economy. Furthermore, SRWCs possibly improve water quality due to their capacity to take up dissolved nutrients coming from agricultural fertilizations. Therefore, this study evaluated the nutrient mitigation potential of flood-tolerant SRWCs established as a bioenergy plantation. In 2018, we established a riparian bioenergy plantation in Sidon, MS in the LMAV. Our plantation had two planted blocks, each containing 75 individuals of black willow (<em>Salix nigra</em>), eastern cottonwood (<em>Populus deltoides</em>), and American sycamore (<em>Platanus occidentalis</em>), and two unplanted blocks (control). To collect shallow groundwater samples, we installed 16 groundwater wells (2 m depth) along the elevational gradient of the plantation. We collected groundwater samples monthly in 2018, 2019, and 2021, and biweekly in 2020 when the plantation was not flooded. We analyzed dissolved organic carbon (DOC) and nutrient concentrations in the samples, such as nitrate, ammonia, orthophosphate, and total phosphorus. To test the hypothesis that our plantations could mitigate nutrient runoff, we used a linear mixed effects model by considering locations where water samples were collected as fixed effects, and blocks and date of data collection as random effects. Our preliminary results showed that with an average nitrate concentration of 1.77 mg/L from adjacent agriculture, our plantation was successful at mitigating 90% of nitrate in 2019 in planted blocks, while there was no significant mitigation of nitrate in unplanted blocks. In both planted and unplanted blocks, there was a significant increase of DOC concentrations in 2020. However, before its discharge into the river, the average DOC concentration detected in the unplanted blocks (27.35 mg/L) was about 3 times higher than that of planted blocks. No significant mitigation of ammonia and orthophosphate has been observed yet. Our results suggested that SRWCs could mitigate nitrate runoff. Therefore, planting flood-tolerant SRWCs for bioenergy along the marginal floodplains potentially improves the water quality of the LMAV.
C.C. Lynch Sponsor Presentation
Year: Authors: Lynch M.
Water quality conditions in many regions are evolving over time and so, too, are the technologies that are used to measure these changes. Continuous water quality monitoring allows for an expanded temporal view of conditions at a particular site of interest. Multiparameter platforms have sensors available for the measurement of algae and some of the parameters of interest that drive or are affected by blooms. Algae-specific sensor technologies include fluorescence-based sensors designed to monitor chlorophyll-a, phycocyanin, and phycoerythrin. By using these sensor technologies connected to a data telemetry device and then to a cloud-based data hosting platform, real-time data-driven decisions can be made intelligently and in a cost-effective manner.
Examination of rainfall variability in the Bahamas using data from a volunteer rain gauge network
Year: Authors: Fuhrmann C., Wells J., Rodgers J.
Water resources in the Bahamas are currently under increasing stress from several factors. Rainfall in the region has been declining in recent decades and the latest suite of climate models from the Intergovernmental Panel on Climate Change suggest that this trend will continue in the future. Moreover, many Bahamian islands are experiencing population growth and an expansion of tourism, both of which lead to greater demands for potable water. Small islands like those in the Bahamas are especially prone to the combined effects of climate change and increasing population because of their limited land area and because rising sea levels are negatively impacting the freshwater lens. Despite these concerns, there is a dearth of basic water resource information in the Bahamas, including measurements of rainfall. As freshwater consumption continues to deplete much of the groundwater storage, it becomes increasingly necessary to explore surface-based storage options such as catchment systems, which are strongly influenced by rainfall patterns. In 2017, we received funding through the 100K Strong in the Americas Program to collect rainfall data on the Bahamian island of San Salvador as part of the Community Collaborative Rain, Hail, and Snow network (CoCoRaHS). This is a volunteer network whereby local residents record rainfall once a day from manual rain gauges. Through the grant, we were able to install several gauges and recruit and train volunteers to record rainfall on San Salvador. Many of these gauges now have over four years of daily data. In this presentation, we provide a summary of the spatial and temporal patterns of rainfall across San Salvador during the period 2018-2021. In addition, we explore the different synoptic-scale weather types associated with rainfall on the island using surface weather maps, which provide insight into the processes that help generate rainfall. CoCoRaHS gauges have also been installed on other Bahamian islands, allowing us to better understand the important variation in rainfall and associated weather patterns across a larger portion of the Bahamian archipelago. In doing so, we hope to promote sustainable water resource management in the Bahamas that accounts for both short-term weather variability and long-term climate change.
Effects of Microcystin-LR on channel catfish susceptibility to microbial pathogens
Year: Authors: Marchant A., Ford L., Petrie-Hanson L., Peterman B., Hanson L.
Cyanobacterial blooms have become increasingly common in natural water bodies and aquaculture systems. These blooms can release several toxins that are health risks for many species including humans, domesticated animals, wildlife, and fish. The most studied environmentally stable toxin produced by cyanobacteria is the hepatotoxin, Microcystin (MC-LR). Channel catfish (<em>Ictalurus punctatus</em>) ponds often have blooms that express MC-LR, but losses due to the toxin are rare. However, we believe that the toxin may be a predisposing factor of losses in catfish to summer pathogens due to the effects that MC-LR has on the liver. In our studies, we investigated the effects of a known dosage of MC-LR on the channel catfish liver, and its effects on channel catfish susceptibility to the summer bacterial pathogens <em>Edwardsiella piscicida</em> and <em>Aeromonas hydrophila</em>. In the first trial, treatment fish were intracoelomically injected with a 500 ng/g bw dose and were sampled along with control fish over a 6-day period. The MC-LR treated fish were not visibly affected but completely stopped eating, when sampled all treated fish through day 4 had no ingesta and had full gall bladders, most control fish demonstrated ingest a in the gut and lighter colored typical gall bladders. Serum aspartate aminotransferase and alanine aminotransferase levels were significantly elevated from 6 hours through 96 hours post-exposure indicating hepatotoxicity. Alkaline phosphatase and bilirubin levels were not substantially affected. Histology confirmed substantial hepatic injury among the treated fish. Later trials that contained both MC-LR and the bacterial pathogens resulted in significantly greater mortality in the treatment group containing both MC-LR and the bacteria in comparison to bacteria only treatments, and no losses within only MC-LR. Our study demonstrated exposure to subclinical doses of MC-LR, can compromise the function of the liver and digestive system and these are critical organs of the innate immune defenses which may have resulted in the increased mortality when encountering bacterial pathogens.
Tile Drainage, Sub-Irrigation and Furrow Irrigation for Soybean Production in Mid-South Mississippi Delta
Year: Authors: Singh G., Kaur G., Quintana N., Gholson D., Krutz L.J., Dodds D.
Mississippi State receives annual average precipitation of 1372 mm. More than 60% of the annual total precipitation is received during late winter or early spring (December to March). Low temperatures along with greater precipitation results in drainage issues in the Mississippi Delta Region. In this region land under row crop production is land-formed to 0.05 to 0.1% slope to help with better surface drainage. Surface and subsurface drainage has been a long-term issue that growers face during every growing season. Due to inadequate subsurface drainage planting, corn and soybean are often delayed in this region. Delayed planting combined with lower precipitation and higher temperatures during summers often results in yield drags. Therefore, supplemental irrigation as furrow irrigation is a common practice among the Mississippi growers. Tile drainage and sub-irrigation are new concepts in the Mid-South US. Sub-surface drainage using tile can be a potential game-changer for the Mississippi growers. Early planting windows for row crops in Mississippi are narrow. Tile drainage can help to drain the subsoil and can help with widening the planting windows. The overall objective of this study was to evaluate tile drainage plus subirrigation system in the Mississippi Delta. The specific objectives were to evaluate soybean production on non-tile drained non-irrigated, non-tile drained furrow irrigated, tile-drained furrow irrigated, and tile-drained sub-irrigation treatment plots and to evaluate the effect of the tile drainage on the drying and wetting of the soil profile for two different tile spacings. This research project was established in summer 2021 on a Sharkey clay soil series having more than 70% clay content with two tile spacings 15' and 20'. The year 2022 will be the first year to evaluate the effect of drainage treatments on soybean production. Sentek soil moisture sensors were installed in Jan. 2022 to a depth of 91 cm to monitor soil moisture changes from non-tile drained and tile-drainage treatments. Tile drainage installation design and preliminary data on soil and soil moisture will be presented at the conference.
Cover Crops and Irrigation Impacts on Soybean Production in the Mississippi Delta
Year: Authors: Kaur G., Russell D., Singh G., Quintana N.
Excessive groundwater pumping for irrigation has declined water levels in the Mississippi River Valley Alluvial Aquifer. Potential solutions to groundwater conservation can be adopting management practices such as irrigation scheduling using sensors and planting cover crops. A study was conducted from 2019 to 2021 at the National Center for Alluvial Aquifer Research, Leland, MS to determine the impact of cover crops and sensor thresholds for irrigation scheduling on soybean production, water productivity, and irrigation water use efficiency (IWUE). The cover crops included in the study were: cereal rye (<em>Secale cereale</em> L.), hairy vetch (<em>Vicia villosa</em> R.), wheat (<em>Triticum aestivum</em> L.) + radish (<em>Raphanus sativus</em> L.) + turnip (<em>Brassica rapa</em> L.) mix, and no cover crop control. Irrigation treatments included: no irrigation/rainfed, -40 kPa, and -90 kPa sensor threshold for irrigation initiation. The experimental design was a randomized complete block with four replications. The highest soybean yield was obtained in hairy vetch treatments under the -40 kPa irrigation threshold in 2020. No significant differences were found for soybean yield in 2021. Water productivity was at least 10% lower in all treatments under the -40 kPa irrigation threshold compared to all other treatments in 2020. The water productivity was highest in -90 kPa followed by no irrigation and -40 kPa sensor threshold treatments in 2021. The IWUE was higher in cereal rye treatment than the other cover crop treatments in 2021. When data was averaged over two years, net returns above total specified expenses were highest in no cover crop treatments under the -40 kPa irrigation threshold.
Water Use Efficiency & Reuse
Year: Authors: Vargas A., Singh G., Kaur G.
Groundwater resource is the most exploited resource for furrow irrigation used in Mississippi The overuse and excessive pumping from agriculture and fisheries has exceeded the natural water recharge of the Mississippi River Valley Alluvial Aquifer. There is limited research available on the use of overhead irrigation systems in corn production systems in the Mississippi Delta. Therefore, understanding the relation between sensor-based irrigation scheduling and nitrogen management using a lateral move system is essential to effectively apply water and nitrogen (N) for sustainable production. The objective of this study was to evaluate the effects of sensor-based irrigation with different nitrogen rates on corn yield and yield components. This study was conducted at Delta Research and Extension Center, Mississippi State University, Stoneville, MS in 2021. Treatments included in this study were three irrigation scheduling thresholds (-40, -70, and -100 kPa) and a rainfed treatment, four N rate applications (0, 112.3, 224.5, and 336.8 kg ha<sup>-1</sup>), and two distinct soil textural classes (Sandy Loam and Clay). The experimental design was a 4✕4✕2 factorial arrangement of treatments in a randomized complete design, with five replications. Data collected included plant height, plant population, SPAD meter readings, corn biomass to estimate N uptake in irrigation and N rate treatments. At harvest, grain samples were collected to determine grain N uptake and grain quality. Corn grain yield was adjusted to 15.5% moisture. Data collected was analyzed using the GLIMMIX procedure in SAS statistical software at a p-value of 0.05. The results for this research will be presented at the conference.
Economic Assessment of Pluvial and Irrigation Runoff Recycling to Stop Aquifer Depletion in the Mississippi Delta
Year: Authors: Quintana N.
We explore the economic merits of on-farm water storage with tail-water recovery systems to reduce aquifer depletion in Sunflower County, MS—a region with expanding irrigated acreage and substantial off-season precipitation. Optimal management gain potential is substantial on a broad scale and long planning horizon, including more than $4 billion in producer surplus, 5 million acre-feet of conserved groundwater, and land capitalization of $24 per acre. Sensitivity analyses provide insights with respect to the impact of discount rates, rainfed returns, return flows, and aquifer recharge rates. The main contrast between our framework and previous analyses of On-Farm Storage economics is that we assess its merits over the net present value of the stream of profits over the life of the aquifer while previous studies employ a seasonal profit maximization framework over no more than 30 years of planning horizons. The insight of a long planning horizon is that it exploits the high recovery value at the end of the infrastructure useful life (the more cycles the relatively cheaper it is to maintain). The optimization over the life of the aquifer rather than over each period brings to account the merits of conservation: a reduction in groundwater used today results in cheaper pumping costs in the future, an effect that is lost in myopic optimization. Results can inform stakeholders about the optimal allocation of funds directed at agricultural practice adoption and agricultural water investments.
Testing requirements and results on water for fruit and vegetables under the Produce Safety Regulation
Year: Authors: Abdallah-Ruiz A., Bond R.F., Silva J.L.
The US Food and Drug Administration has a new regulation as part of their Food Safety Modernization Act, titled "Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption." Under this rule there is a subpart proposed titled "Agricultural Water." The rule states that farmers should evaluate risks associated with water as a possible source of contamination of product that will reach commerce and develop mitigation strategies to minimize these risks. Water has been known to be the source of many produce foodborne outbreaks. Water has been implicated as the possible vector of <em>E. coli</em> STEC (O157:H7) in romaine and other leafy greens, affecting the health of many consumers, leading to hospitalization and death in some cases. One of the factors is the source of water and possible contamination sources. Testing of the water source and at any other points could help assess the quality/safety of it and whether mitigation strategies are needed. The analyte to test, whether it is well or surface water, is <em>E. coli</em>. Sampling and testing procedures approved usually follow those approved by EPA for recreational waters. In addition, farmers can test for possible pathogens that may be in the water. Limited testing has shown that well water usually meets the desired quality (GM and STV of 126 and 410 CFU or MPN/ml in 100 ml, respectively). However, surface water samples at times do not meet the criteria for <em>E coli</em> and have been found positive for some pathogens (<em>Salmonella</em> most often).
Detangling Tanglewood: Characterizing vertical, horizontal, and longitudinal hydrologic connectivity in a Coastal Plain headwater stream
Year: Authors: Peterson D.M., Jones C.N., Shogren A.J., Plattner A., Godsey S.E., Atkinson C.L., Benstead J.P.
Upstream hydrologic processes affect the chemical, physical, and biological function of downstream aquatic ecosystems. However, there are systematic gaps in our understanding of watershed storage and connectivity dynamics that limit our ability to effectively manage downstream waters—particularly in Coastal Plain landscapes. We are working to bridge this gap by characterizing drivers of vertical, horizontal, and longitudinal hydrologic connectivity in a 90-ha headwater stream in the Upper Coastal Plain of western Alabama. We first identified three distinct hydrogeomorphic features based on varying degrees of stream incision. We then installed a network of nested shallow groundwater wells across these features and performed seasonal stream network surveys to capture variable scales and dimensions of water movement. Additionally, we used an Electrical Resistivity Tomography (ERT) survey to characterize subsurface structure. Results suggested that vertical connectivity is constrained by discontinuous clay layers based on observed water table perching and evidence of preferential flow through the clay confining units. Horizontal connectivity (i.e. both hillslope storage and connectivity) was driven by the degree of incision; the incised reach consistently received water from the hillslope, whereas the depositional reaches were consistent sources of water to the hillslope. Finally, longitudinal connectivity was a function of both stream incision and season, as stream drying was variable across seasons, but stream width distributions followed unique seasonal patterns that were variable across stream hydrogeomorphology types. Our results provide an initial characterization of how upstream processes impact downstream water quality in low-gradient, Coastal Plain watersheds.
Computing the Effectiveness of BMP implementation on water quality and hydrology in Yazoo River Basin by modelling approach
Year: Authors: Venishetty V., Parajuli P.B.
Deterioration of water quality due to non-point source (NPS) pollution is prominent across the world. Agriculture is the major source of NPS pollutants that is mainly induced by runoff. Yazoo River Basin (YRB) is the largest watershed in the state of Mississippi, of which about 47% of land use is large scale agriculture and the remainder is Forest (50%), wetlands, water and urban (3%). Major Crop in the region are Corn, Soybean and Cotton. Continuous and Crop rotation practices are applied in the region. To minimize and mitigate pollution from agricultural lands, numerous Best Management Practices (BMP) were being implemented in the state and country. By using Soil and Water Assessment Tool (SWAT), impact associated due to BMP implementation is quantified. SWAT model efficiency has been tested using Nash-Sutcliffe Efficiency index (NSE) and Coefficient of Determination (R<sup>2</sup>). Calibration and validation of various Hydrologic (Streamflow) and water quality parameters (Total Suspended Sediment (TSS), Total Nitrogen (TN), and Total Phosphorus (TP)) is done for various USGS gage stations spread across the watershed. Model performance is Good for streamflow, Satisfactory for TSS, TN and TP. Management practices such as Vegetative Filter Strips (VFS), Tail Water recovery Ponds (TWP), and Cover Crops were preferred for analysis in this study. Simulations from VFS implementation show significant reductions in sediment, and nutrient concentrations in water, and similar results are expected to be found from TWP and Cover crop practices as well. Hence it is essential to understand and quantify the impact of BMP on water quality.
Impact of freshwater diversions on vegetation in coastal wetlands based on remote sensing derived vegetation index
Year: Authors: Wu W., Grimes E., Suir G.
To improve understanding on the efficacy of large-scale freshwater and sediment diversion projects in restoring coastal wetlands, we aim to evaluate the long-term changes in wetland vegetation in diversion outfall areas.<br><br> We selected two diversion outfall areas (Caernarvon and Davis Pond, LA, U.S.) as the study sites and compared them to the reference wetlands nearby with similar pre-diversion vegetation compositions. We implemented multi-level Bayesian models to evaluate 1) how peak-season Landsat-derived Normalized Difference Vegetation Index (NDVI) changed over time in reference to the initiations of the freshwater diversions, and 2) how peak-season NDVI responded to mean and variability of inundation and salinity, key abiotic factors that would be affected by freshwater diversions.<br><br> Analysis showed differences in temporal trends of NDVI for the Caernarvon project, and differences in how inundation and salinity impacted NDVI between the reference and diversion sites, indicating that diversions played a key role in affecting vegetation. For the Caernarvon diversion project, variability of water level (inundation) and salinity and mean salinity were important to affect NDVI, while mean water level and mean salinity were important for the Davis Pond diversion project. The variability has not been traditionally accounted for in quantitative models but can be more important to consider than the mean levels.<br><br> The study provides a modeling framework that can comprehensively evaluate freshwater diversions with uncertainties accounted for. It will inform future use of freshwater diversions for wetland restoration.
The influence of marsh edge and seagrass habitat on fish and macroinvertebrates in a northern Gulf of Mexico coastal system
Year: Authors: Gilpin R., Cebrian J., Baker R., Offner T., Ramsden S.
Habitat is one of the most important services provided by coastal ecosystems. In estuaries in the northern Gulf of Mexico (nGOM), marsh grasses and seagrass beds provide habitat for many fish and crustacean species (i.e., nekton) of ecological, commercial, and recreational importance. Namely, the structural complexity of marshes and seagrass beds provides excellent refuge and food resources, making them ideal nurseries for the recruitment of estuarine-dependent juveniles. Although both marshes and seagrass beds have been widely recognized as important nursery habitat for estuarine species, few have analyzed how these habitats interact and function together, thereby limiting our understanding of the variability of juvenile recruitment to coastal systems. Our objective is to assess the interaction between fringing marsh and adjacent seagrass for the provision of habitat for nekton. Our preliminary analyses point to evidence of functional habitat redundancy between fringing marshes and adjacent seagrass beds. Namely, indicating that in the location of study, fringing marsh and seagrass beds offer similar levels of habitat value to recruiting juveniles. At any rate, further analysis of our data is needed to confirm these preliminary results. Understanding how intertidal marshes and adjacent seagrass beds interact and function together is essential for implementation of concerted conservation and management efforts for these important nursery habitats.
Bayous to Beaches: Connecting inland behaviors to the health of the Gulf of Mexico
Year: Authors: Dalessandri S., Blackmon L.
The University of Southern Mississippi's Marine Education Center, with support from the EPA, has developed a Meaningful Watershed Educational Experience (MWEE) curriculum which can be easily implemented into the classroom. Target audience are grades 7-12, however with a bit of modification younger students can also participate. The program focuses on connecting behaviors on land and upriver to water quality along the Gulf Coast. The curriculum comes in the form of brief educational videos designed for classroom viewing, each addressing an aspect of watershed health. Suggested activities accompany each video engage students by promoting hands on engagement and critical thinking. Over the past 3 years, teachers from the Gulf Coast region and as far away as the central Midwest have participated in this project through teacher professional development workshops and student field experiences at our coast Mississippi outdoor education center. Each group brought new perspective and the last few years carried with it many challenges. These challenges inspired us to extend our reach by creating a standalone curriculum which can be delivered virtually and be taken into the field at the discretion of the implementing teacher. The resulting curriculum aims to reinforce the connection and shared stewardship responsibility among all who live within important watersheds.
Hydrologic Performance and Life-Cycle Cost Analyses of Green Stormwater Infrastructure
Year: Authors: Abera L.E., Surbeck C.Q., Alexander K.
Urbanization increases impermeable land cover by diminishing other permeable land covers such as grass and forests. This change affects the hydrology of urban areas and results in excess stormwater runoff or flooding events. A sustainable way to reduce the amount of impermeable surfaces and allow stormwater to infiltrate into the ground is to use green stormwater infrastructure (GSI). In this study, computer simulations were performed to assess the hydrologic performance of GSI in runoff reduction. Life-cycle cost analyses (LCCA) of stormwater infrastructure were also performed to determine the cost-effectiveness of GSI practices, considering capital and operation and maintenance (O&M) costs.<br><br> This presentation will show the economic and hydrologic analyses results of green stormwater infrastructure for a proposed development site in Oxford, Mississippi. The HydroCAD stormwater modeling tool was used to perform hydrologic modeling for three types of GSI: permeable pavement, rain garden, and grassy ditch. The site was modeled using the curve number reduction method, which reduced the weighted average curve number of the site when GSI was implemented. The peak flow and volume of stormwater runoff were estimated for multiple scenarios based on the city's design storms. Depending on the type and size of the GSI and the storm intensity, the simulation results showed that applying GSI reduced the volume of excess runoff by 12% on average. Of the three GSI scenarios, the rain garden resulted in the highest reduction in the volume of stormwater runoff. A life-cycle cost analysis was performed using the Water Environment Research Foundation (WERF) Low Impact Development Cost Analysis Tools. Based on the LCCA results, the net present cost of GSI scenarios is higher than for traditional stormwater infrastructure. However, the LCCA does not include other external factors, such as environmental and health benefits. A co-benefit analysis was conducted using the Community-enabled Life-cycle Analysis of Stormwater Infrastructure Costs (CLASIC) tool to quantify these benefits.
Downscaling GRACE Equivalent Water Thickness Data for Mississippi Using Neural Nets
Year: Authors: Awawdeh A.R., Yasarer H., Pulla S., Kumar M.
The importance of having high-resolution and effective hydrological data has increased with the recent climate change and continuous relying on underground water. Having such data has been made possible after launching the Gravity Recovery and Climate Experiment (GRACE) in 2002. GRACE enabled researchers to extract data about terrestrial water storage, ice loss, and sea-level change in a temporal resolution of one month. Although this was a great achievement, it is still can't be relied on for small regions because the GRACE data grids are very coarse, i.e. 25 km by 25 km. The goal of this paper is to address the efficiency of using Feedforward Artificial Neural Networks (ANNs) with backpropagation error algorithm to scale down GRACE precipitation data for the State of Mississippi to smaller grids to be used on smaller regions. Both Climate Hazards group Infrared Precipitation with Stations (CHIRPS) and TerraClimate will play an important role in the downscaling process. CHIRPS provides a high-resolution rainfall dataset while TerraClimate provides a dataset of monthly climate and climatic water balance for global terrestrial surfaces. A script in Python programming language and executed via Jupyter Notebook was developed to download all the needed data as well as for the ANN model development. Preliminary results showed that the ANN approach performed well with a significant accuracy and the developed models can be utilized to predict Equivalent Water Thickness with a high accuracy in the Mississippi region.
Characterization of plastic Lay-flat irrigation tubing material properties and outlet flow performance as impacted by mil thickness and internal tubing pressure
Year: Authors: Caey D.
Lay-flat irrigation tubing, or poly-pipe, has become a low-cost solution for flood irrigation on leveled-to-grade farmland through the Mid-South. Poly-pipe is available in a range of diameters and material thicknesses in lengths of up to one-quarter mile, providing the flexibility to be adapted to meet variable field conditions and flow requirements. System challenges include management of even flow distribution across the length of installed poly-pipe sections and poly-pipe failures from over-pressurization. Computerized hole selection (CHS) prescriptively determines the optimum outlet hole size for each furrow, providing the desired water output to maximize water use efficiency. Poly-pipe failures are common and are believed to result from improperly selected poly-pipe diameter and thickness and can also be influenced by incorrectly sized outlet holes at the furrows, creating elevated internal tubing pressures that result in material deformation. Theses failures can be identified as catastrophic, such as in a complete failure, or rupture, of the poly-pipe. However, over-pressurization can also result in stretching/elongation of outlet holes before complete material failure occurs, altering hole geometry and significantly affecting the flow dynamics of the hole. However, little research exists to quantify these factors and their relationships as causal agents for failure. The objectives of this study were to characterize poly-pipe performance by: 1) quantification of material properties of available poly-pipe mil. thicknesses, 2) evaluation of the interaction of poly-pipe thickness and internal pressure on failures. Virgin poly-pipe samples were analyzed in static conditions utilizing ASTM D882-18 "Standard Test Method for Tensile Properties of Thin Plastic Sheeting" in an MTI 2K Bench-Top Universal Testing System to capture the material properties in tension (modulus of elasticity, burst strength, and tensile strength) for each mil. thickness. Each thickness of poly-pipe was found to be significantly different (p<0.0001) across the assessed material properties analyzed. Further analysis was conducted in dynamic conditions simulating hole flow/pressure relationships to evaluate hole reaction to pressure changes. Single holes were punched in 44-inch sections of 7, 9, and 10 mil poly-pipe, and subjected to increasing pressures of up to 150% of yield tensile strength. Flow rates were captured at four pressures up to 100% of calculated yield tensile strength, at 150% of yield tensile strength, and the subsequent four pressures post 150%. Significant differences (p<0.0001) were observed between pre and post over-pressurization for all mil thicknesses, with differences being more pronounced in the 7 mil poly-pipe. No significant differences were observed between poly-pipe diameters of the same mil thicknesses. Further analysis is ongoing to assess the effects of over-pressurization in multi-hole poly-pipe configurations to assess if the effects are consistent across all holes.
Investigating the contribution of modified P-enriched biochar on acid soil's pH buffering capacity
Year: Authors: Carter K.S., Beatrice A., Varco J.J., Dygert A., Brown S., Pittman Jr. C.U., Mlsna T.
Biochar can directly hold cations in soil because of the negative charge that exists on its surfaces. Besides, improving soil cation exchange capacity, the negative charges on biochar surfaces can buffer acid soil by protonation and deprotonation mechanisms. Moreover, biochar can ameliorate soil acidity due to the presence of oxide, carbonate and hydroxide of its basic cations (Ca, Na, K, and Mg). Both biochar surface functional groups and basic cations concentrations can be altered by modification with chemical agents (Chemerys, 2017; Godwin et al., 2019), which could affect its soil pH buffering capacity. However, information concerning the impact of modified biochar application on soil pH buffering capacity is still scanty. This study investigated the pH buffering capacity of acid soil amended with three P-enriched modified Douglas fir biochars and compared this to amendment with untreated Douglas fir biochar. These three P-enriched biochars, designated CCPP, CAPP and MSPP, were prepared by treating Douglas fir biochar respectively, with: 1) anhydrous calcium chloride (CaCl<sub>2</sub>) and potassium phosphate monobasic (KH<sub>2</sub>PO<sub>4</sub>), 2) calcium carbonate (CaCO<sub>3</sub>) and diammonium phosphate {(NH<sub>4</sub>)<sub>2</sub>HPO<sub>4</sub>} and 3) aqueous solution of magnesium sulfate (MgSO<sub>4</sub>), potassium hydroxide (KOH) and potassium phosphate monobasic (KH<sub>2</sub>PO<sub>4</sub>). The acid soil was then treated with biochar samples in biochar: soil ratios of 0%, 10%, 30%, and 50% (w/w), followed incubation for 30 days at room temperature with soil moisture levels maintained at 80% field capacity. The soil-biochar mixtures were titrated with 0.1 M aqueous HCl solutions and the resultant pH values determined. The amount of H+ added to soil-biochar mixture was plotted against pH. The pH buffering capacities of the soil and the soil-biochar mixtures were obtained from the graph's slope. The soil pH buffering abilities were largely dependent on the added biochar's alkalinity and ash contents.
Impacts of Furrow Irrigation Spacings in Sharkey Clay Soils Under Corn Production
Year: Authors: Freeland T.B., Gholson D., Kaur G., Singh G.
More than 40% of the land in the Mississippi Delta is classified as clayey soils. In MS, the majority of corn is produced on either sandy loam or silt loam soils. Clayey soils are now being brought into the list of soils growers produce corn on due to it's economic return. The risks associated with these soils, like frequent flooding and waterlogging, are a hurdle for farmers. Corn can lose 5-30% yield with each day of soils being flooding depending on the stage of corn. The objective of this research is to find out if altering furrow irrigation spacings can reduce or eliminate the waterlogging of corn in these soils and boost corn yield. A field experiment was conducted at NCAAR in 2021 using a complete randomized block design with four replications. Furrow irrigation spacings replications include every row irrigation (ER), 1-meter skip row irrigation (1R), 3-meter skip row irrigation (3R-I and 3R-NI), and 7-meter skip row irrigation (7R-I and 7R-NI). Data on irrigation water applied, volumetric water content, plant population, plant heights, crop water stress index, multispectral imagery, corn yield, and grain quality was collected from this study. No significant differences were found between ER and 3R-NI treatments for corn yield. The 7R-NI had 9.21% lower yield than all other treatments except 3R-I and 1R. The 3-meter skip row irrigation treatment showed 1.29% higher volumetric water content than all other treatments. The 3-meter skip row treatment held the highest volumetric water content across all seven middles, showing that the water moved laterally through the treatment. Results from the first year of this study indicate that there was ample subsurface later movement of water in the 3-meter skip row irrigation treatment to meet crop water demands.
Evaluation of automated sampling protocols for edge-of-field water quality monitoring
Year: Authors: Hill M., Ramirez Avila J.J., Baker B., Evans K.O.
Recent efforts to document the efficacy of suites of conservation practice impacts on water quality have utilized automated edge-of-field water sampling units. Automated sampling procedures involve the collection of composite samples to estimate event mean concentrations which are multiplied by measured discharge to ascertain stream nutrient loading from agricultural landscapes. However, a central and critical step in sample collection procedures is the programmed automated trigger to engage sampling of a runoff event which is designed to represent nutrient concentrations across a runoff hydrograph. However, given the variability in intensity and duration of runoff events, program conditions could have an impact on measured nutrient concentrations and thus estimations of nutrient transport. This study aims to understand the tradeoffs related to sampling protocol by examining differences in nutrient concentrations collected with three different sampling regimes: time-series, flow-weighted by volume, and flow-weighted by change in flow rate. Samplers were installed side-by-side to test the sampling protocols during individual runoff events, the side-by-side trials were replicated in three row-crop agricultural fields in the Mississippi Alluvial Valley from May 2021 through May 2022. Water samples were analyzed for non-point source pollutants of concern: Total Nitrogen, Nitrite-Nitrate -N, Total Kjeldahl Nitrogen, Total Inorganic Phosphorus, Turbidity, and Total Suspended Solids. A multivariate approach is used to parse the influence sampling protocol, season, farm and sensor configuration are having on water quality indicators. Results will help us understand the relative accuracy of nutrient transport estimations in studies that utilize edge-of-field monitoring to examine conservation practice efficacy in agricultural landscapes. Further, results may indicate which sampling protocol is most effective in the widest range of magnitudes of runoff events, providing practical guidance for monitoring efforts.
Understanding the impacts of silvicultural activities on downstream sediment export and ecosystem function via experimental sediment additions
Year: Authors: Kohler L.D., Speir S.L., Atkinson C.L.
Increased sediment export in streams has significant downstream impacts, decreasing water clarity, negatively impacting aquatic organisms, and increasing the export of sediment-bound nutrients. However, the construction of forest roads and other silvicultural activities are considered "non-point sources" of pollution under the Clean Water Act. This "silvicultural exemption" allows forestry companies to directly dispose of dredged material into streams without permits. Thus, it is critical to determine the impacts of dredged material on sediment dynamics in streams. Here, we quantified the impacts of sediment discharge on stream ecosystem function using a Before-After Control-Impact (BACI) design. We simulated a sediment discharge event in our impact stream reach, then measured stream turbidity, total suspended solids, and phosphorus concentrations in both the control and impact reaches; this was repeated twice to capture both low- and high-flow conditions. We also deployed dissolved oxygen sensors at the top and bottom of each reach to estimate stream metabolism. Preliminary results indicate that increased turbidity, associated with the disposal of dredged material, results in decreased light penetration in the water column and reduces in-stream primary productivity. Our study will shed light on the impacts of forestry-related sediment disposal on both in-stream function and sensitive downstream systems that can inform forestry best management practices and legislation.
Characterizing Inundation Regimes of a Lowland, Bottomland Hardwood Forest
Year: Authors: Perera N., Shockey M., Jones N.
In bottomland hardwood forests, such as those surrounding the Sipsey River in Western Alabama, the magnitude, frequency, duration, and spatial extent of flooding drive the structure and function of the floodplain ecosystem. Hydrogeomorphic features (i.e., sloughs) impact both local scale inundation dynamics and downstream flooding. In this study, we quantify dynamic water storage in a lowland floodplain using a two-dimensional hydrodynamic model built with the U.S. Army Corps of Engineers' Hydrologic Engineering Center River Analysis System (HEC-RAS). Traditionally, hydrodynamic models are used to analyze the extent and duration of flooding. However, we will use the results of our model to quantify changes in water storage in floodplain sloughs along an 18 km reach. The floodplain was modeled using Digital Elevation Model (DEM) data from USGS, and then validated using 77 years of flow data collected from USGS Gage 02446500. The results from this model will be used to predict how inundation regimes impact the structure and function of bottomland hardwood forest ecosystems.
Assessment of flood inundation mapping of the Catalpa Creek Watershed in Mississippi by 2-d hydraulic modelling
Year: Authors: Poudel S., Roldan M., Ramirez Avila J.J., Czarnecki J., Schauwecker T., Achury S.O.
The Catalpa Creek Watershed in Mississippi is very susceptible to flooding events especially flash floods. The watershed is characterized by very mild slopes and alluvium clay rich soils which make the basin highly vulnerable to flooding. Although floods cannot be controlled completely, the flood risk hazards can be minimized by having an advance information of extreme flood prone zones of the watershed. By predicting the water level of the adjoining streams in different rainfall scenarios, the flood inundation extent of a location within the watershed can be identified. To assess the flood inundation, hydrologic simulations are carried out and a 2-D hydraulic model of the watershed is developed. The Hydrologic Modeling System (HEC-HMS) is used for the hydrologic modeling work, whereas the River Analysis System (HEC-RAS) model is used to develop the hydraulic model and flood inundation map. The flood depth, water surface elevation and velocity distribution are simulated to determine the extent of flooding. The developed hydraulic model is calibrated based on the Manning's roughness coefficient by comparing with the downstream rating curve. The results obtained from the model are maximum water depth and maximum flood velocity at the time of peak runoff for several flood prone zones within the watershed.
Furrow Infiltration Estimation in a Surface Sealing Loam Soil
Year: Authors: Rix J.P., Lo T.H., Gholson D.M., Singh G., Rudnick D.R.
Seven different soil management treatments categorized as biological, chemical, and mechanical are being tested as possible remedies for reoccurring surface sealing on Mississippi Delta loam soils. The treatments include conventional tillage, medium-term no-till, new no-till with gypsum, cereal rye, subsoiling, polyacrylamide (PAM), and furrow diking. In 2021, field-satiated hydraulic conductivity was measured by single ring infiltrometer tests for two treatments, medium-term no-till and conventional tillage, in June and October. Analysis of variance suggested no significant difference between the two treatments in terms of mean natural logarithm of field-satiated hydraulic conductivity. 2021 rainfed corn grain yield results were subjected to Fisher's Least Significant Difference test. Furrow diking and PAM were found to be higher and statistically different than no-till with respect to mean yield. Future work will include single ring infiltrometer tests on four treatments: cereal rye, PAM, subsoiling, and conventional tillage.
Stream channel characterization in the Catalpa Creek/Red Bud Creek watershed in Mississippi
Year: Authors: Roldan M., Ramirez Avila J.J., Achury S.O., Schauwecker T., Czarnecki J.
The Catalpa Creek watershed is located in the northeastern part of Mississippi, in Oktibbeha and Lowndes County. The Mississippi department of environmental quality (MDEQ) has listed Catalpa Creek as an impaired waterbody due to sediments. As the city of Starkville and the Mississippi State University Campus are in the headwaters of the watershed, they play an important role in the generation of runoff and acceleration of stream processes in the watershed. A study is conducted hypothesizing the Rosgen's bankfull indicator based classification system can be systematically and consistently applied to the Catalpa Red Bud/Catalpa Creek watershed and potentially, the Tombigbee River Basin in Mississippi. The morphological classification of benchmarked stream channel reference sites along the mainstream and tributaries within the Red Bud/Catalpa Creek Watershed is conducted at the level II of the Rosgen's Classification. Physiographic characterization of the reaches has been performed since October 2021. Stratification of the Catalpa Creek/Red Bud Creek streams into the correct stream type could lead to a more appropriate prioritization and design of streambank-stabilization, stream restoration, and habitat-rehabilitation projects, and to the potential stratification of assessment and monitoring sampling programs.
A more efficient way of integrating Watershed Boundary Dataset (WBD) into web-based Agricultural Integrated Management System (AIMS)
Year: Authors: Sahin A.N., Ozeren Y.
Agricultural Integrated Management System (AIMS) is a web-based tool developed by The National Center for Computational Hydroscience and Engineering (NCCHE) University of Mississippi, and USDA-ARS National Sedimentation Laboratory, for watershed conservation management planning. AIMS is intended to provide a user-friendly environment for data analysis and watershed modeling with automated input data preparation capabilities from seamless geospatial data for any watershed in the United States. Watershed Boundary Dataset (WBD) is used to define the simulation boundaries of AIMS models including the topographic landscape analysis tool TopAGNPS. One of the advancements of the new AIMS environment is GeoJSON data format to represent geospatial features, which required conversion of WBD hydrologic unit boundaries into GeoJSON data format, and re-establishment of the hydrologic unit hierarchy. The conversion enables inter-operation between backend Python and Java modules, and the watershed simulation models running under AIMS, including TopAGNPS, for locally transferring remote or saved structured data independently from the map servers. This allows importing the geospatial data as an object with its hierarchy for backend operations without requiring additional parsing or server-side operations (authentication, data transfer, etc.). This method also increases the stability, security, and speed of the system and decreases its dependency of it on external resources. The key features of the new AIMS platform including the updated WBD will be presented.
Investigating Water Quality Trends in Watersheds with Changing Conservation Adoption
Year: Authors: Lucore A.E., Baker B.H., Hill M.J.
Alongside significant investments in agricultural conservation to address water quality degradation through US government programs is a need to assess conservation efficacy. Conservation practices such as cover crops and reduced tillage have been identified as management strategies with potential to improve water quality outcomes at the edge-of-field scale. However, documenting water quality improvements in impaired waters at the watershed scale is more difficult to monitor and detect. This study aims to address that data gap by assessing historical data in three impaired watersheds in conjunction with more current monitoring data following the implementation of cover crops and reduced tillage conservation practices to detect water quality trends. Historical water quality data was retrieved from U.S. Geological Survey monitoring stations over a ten-year period. Water quality data was also collected in the field by Mississippi State University at each monitoring location following the adoption of cover crops and reduced tillage in each watershed. Data collected from 2018-2020 in Porter Bayou (HUC12 080302071000 ) was analyzed at the Mississippi State Water Quality Laboratory and samples collected from Richies Bayou (HUC12 080302070303) and Overcup Slough (HUC12 080302070302) from 2020-2021 were analyzed at the Mississippi Department of Environmental Quality. Linear regressions will be utilized to explore trends in turbidity, total nitrogen, and total phosphorus concentrations overtime within in each watershed. Results of this study are expected to provide valuable information on water quality trends in impaired watersheds and provide insight for conservation planning.
Multiannual variability of low flow events over the Southeastern United States
Year: Authors: Raczynski K., Dyer J.
Understanding the patterns of low streamflow (a.k.a., low flow) frequency and intensity is critical in defining potential environmental and societal impacts on processes associated with surface water resources; therefore, the objective of this study is to quantify the multiannual variability of low flow river conditions over the Southeastern US. The study was performed using National Water Model retrospective simulations (v2.1), aggregated to daily mean flow values at 73,891 stream segments (of Strahler order 3 and higher) for the period 1979 to 2020. The data were used to calculate annual sums of outflow deficit volumes, from which the autocovariance function (ACF) and the Hurst exponent (<em>H</em>) were calculated to quantify low flow patterns. The ACF approach is commonly used for examining the seasonal and multiannual variation of extreme events, while the Hurst exponent in turn allows for classification of "process memory", distinguishing multi-seasonal processes from white noise processes. The results showed diverse spatial and temporal patterns across the Southeast US study area, with some locations indicating a strong seasonal dependence. These locations are characterized by a longer temporal cycle, whereby low flows were arranged in series of several to dozens of years, after which they didn't occur for a period of similar length. In these rivers, the values of the Hurst exponent were in the range 0.8 +/- 0.15, which indicates a stronger relation with groundwater during dry periods. In other river segments within the study region the probability of low flows appeared random, determined by the Hurst exponent oscillating around the values for white noise 0.5 +/- 0.15. The initial assessment of the Hurst exponent distribution, as well as results of the ACFs, suggests no strict spatial relationships. Also, the correlation coefficients between low flow patterns and river order do not indicate the occurrence of a statistically significant relationship (<em>r</em> ≈ 0.08). The results of the research provide useful information about the spatial and temporal patterns of low flow occurrence across the Southeast US, and also indicate that the NWM retrospective data are able to differentiate the time processes for the occurrence of low flows. The next stage of work will be to estimate the accuracy of the NWM retrospective data in terms of low flow analysis through comparison with observed data from available USGS gauges.
An Interdisciplinary Approach to Community-Engaged Research Surrounding Lead in Drinking Water in the Mississippi Delta
Year: Authors: Willett K.L., Showalter S.E., Janasie C.M., Rhymes J.P., Dickson K.
Childhood lead poisoning is a problem requiring interdisciplinary attention from toxicology, public health, social sciences, environmental law, and policy. In the U.S., Mississippi was ranked as one of the worst states for lead poisoning with limited childhood screening measures. We conducted community-engaged research by working with leaders in the largely rural Mississippi Delta region from 2016-2019 to collect household water samples and questionnaires and involve their communities in lead poisoning risk awareness and outreach. Drinking water from 213 homes was collected and analyzed for pH and lead concentrations. Highest lead concentrations were from households served by private wells, and detectable concentrations at or above 0.09 ppb were found in 66.2 percent of all samples. Nine samples exceeded 5 ppb, and these households received certified sink filters. Findings indicated that community-engaged research and outreach could be used to address data gaps relating to lead in drinking water in rural decentralized water systems.
Microplastics in the Mississippi River and Mississippi Sound
Year: Authors: Cizdziel J.
Led by consumer products, the worldwide demand for plastic continues to grow with global production at nearly 350 megatons in 2017 (Plastics Europe 2018). Unfortunately, careless discarding of plastic and mishandling of the plastic waste stream has resulted in widespread plastic pollution, including the infamous oceanic garbage patches (Lebreton 2018). Further, plastics in the environment weather and degrade as a result of ultraviolet radiation, microorganisms, temperature changes, and mechanical forces (e.g. wave action), yielding smaller and smaller particles called micro- and nano-plastics. Here, we focus on MPs, which have been described as "any synthetic solid particle of polymeric matrix, with regular or irregular shape and with size ranging from 1 ?m to 5 mm, of either primary or secondary manufacturing origin, which are insoluble in water" (Frias 2019).<br /><br /> The occurrence of MPs in the aquatic environment is well documented, with higher concentrations generally found near population centers (Li 2018). MPs have also been detected in remote areas, including the Arctic Ocean (Lusher 2015), deep-sea sediments (Free 2014), and mountain lakes (Cauwenberghe 2013). Given their small size and ubiquitous nature in lakes, rivers, and oceans, their ingestion and impact on aquatic life poses a serious threat, particularly for small suspension-feeding organisms (Auta 2017). Moreover, MPs have been shown to be substrates (vectors) for other contaminants, including persistent organic pollutants such as dichloro-diphenyl-trichloroethane (DDT), both in laboratory studies and in field studies (Teuten 2009; Costa 2017; Tourinho 2019).<br /><br /> Unfortunately, there are often wildly different estimates reported for MP abundances in natural water, even from the same waterbodies, making meaningful comparisons difficult and hindering the utility of real-world MP surveys (Lusher 2017; Lenz 2018; Jiang 2018). Some of these disparate results may be due to inherent variability at the sites, but part of the problem may be the different sampling, sample preparation, and analytical methods used. On one hand, the wide range of approaches to MP analyses is not surprising given that MPs (1) are a diverse class of contaminant encompassing a wide variety of sizes, morphologies, and chemical and physical properties (Rochman 2019), (2) partition into different environmental compartments depending on size, density, biofouling, and other factors (Hartmann 2019), and (3) have only recently (in the last decade) caught the attention of the larger scientific community. On the other hand, MP analytical methods need to become more harmonized to increase the quality and comparability of experimental data.<br /><br /> Two common ways to sample plastic debris suspended in water is through use of a surface or subsurface tow net or by collecting a known volume of water at a specific location (bulk water sampling). Nets are typically used in investigating large areas with results being reported in particles/m3, whereas bulk water sampling is more accurate as a snapshot and is often reported in particles/L. A major drawback to sampling with a net is that it fails to capture particles smaller than the mesh opening (typically 333-?m), and these smaller particles tend to be the most abundant. In contrast, bulk water sampling captures all size fractions of particles in the water. Another advantage of bulk water sampling is the elimination of contamination from sampling equipment such as nylon nets and ropes. However, trawling with a net or bulk water sampling should be considered complementary techniques, covering different parts of the overall MP pollution (Tamminga 2019).<br /><br /> When using a net, the plastics caught in the cod end are typically rinsed out into a container for later processing in the laboratory. Determining the volume of water passing through the net or being pumped through collection sieves is important to accurately calculate MP concentrations. At some point the net and bulk sampling methods converge with the samples being filtered through a sieve or series of sieves to isolate particulates by size fraction(s). Larger particles can be removed by tweezers and analyzed by FTIR or other means. If the remaining solids collected on the sieves or filters are organic-rich they are typically subjected to either enzymatic digestion (Cole 2014) or wet peroxide oxidation, the latter sometimes in the presence of a Fe(II) catalyst (Tagg 2017), to digest labile organic matter and "clean" the plastic surfaces. A final filtering step is used to concentrate the MPs which can then be examined directly on a filter by conventional light microscopy (Masura 2015), stained with Nile Red dye and examined by fluorescence microscopy (Erni-Cassola 2017), or transferred to a spectroscopic window/slide or a suitable filter for chemical imaging by Focal Plane Array (FPA)-?FTIR or Raman spectroscopy (Loder 2015; Tagg 2015; Olesen 2017; Wolff 2019)
Exploring the use of synthetic aperture radar for detecting and monitoring potential long-term subsidence in the lower Mississippi River valley
Year: Authors: Terracina S., Yarbrough L.D.
The Mississippi River alluvial plain (MRAP) is a geophysical province in North America extending from the bootheel of southeast Missouri south along the Mississippi River to the Gulf of Mexico. This study focuses on the lower Mississippi Valley portion of the MRAP that extends from Memphis, Tennessee to Vicksburg, Mississippi and bordered by the Mississippi River to the west. This subset of the MRAP, commonly known as the Delta, is an extensive, low, flat lying area that covers an area of approximately 7,000 square miles and serves as a vital economic resource to the state and region.<br /><br /> Because the Delta is comprised of low strength alluvium, low relief, abundant surface water and shallow groundwater resources, the region is suspectable to several geohazards including flooding, bank stability issues, regional and local subsidence, expansive soils, etc. The New Madrid Seismic Zone to the north also poses additional risk of seismic induced hazards (e.g. liquefaction). Characterizing potential subsidence is of great interest due to increased flood risk along low laying areas near water bodies and impact on levee elevations.<br /><br /> In this project, we investigate the use of the remote sensing technique, interferometric synthetic aperture radar (InSAR) to detect subsidence. InSAR uses waveform phase information of similarly polarized radar pulses from two different acquisition dates to detect displacement on the order of a few millimeters. Preliminary work resulted in the detection of the surface displacement in test locations in southern Louisiana. Our method of analysis was applied to the Delta using the Sentinel-1 satellite platform. The InSAR method relies on a temporal dataset and the greater the time between analysis images the more time is available for displacement to occur. Our initial results show regional subsidence rates are smaller than the detectable limits using InSAR. Additional range (e.g. continued acquisitions) in the temporal database and use of shorter wavelengths could lead to an improved method of subsidence detection and monitoring in the Delta.
Using Tritium and General Geochemistry to Constrain Recharge Estimates within the Mississippi River Valley Alluvial Aquifer
Year: Authors: Wacaster S.R., Knierim K.J., O'Reilly A.M.
The Mississippi River Valley Alluvial Aquifer (MRVAA), one of the regional aquifers within the Mississippi embayment, is a major source of groundwater for irrigation as well as some public supply use within the Mississippi Alluvial Plain (MAP). An aquifer-scale assessment of recharge processes (where water availability is significantly affected) is critical for the economic welfare of Mississippi, Louisiana, Arkansas, Missouri, Kentucky, and Tennessee. Using readily available recharge estimates and groundwater age will allow water quality and availability to be related.<br /><br />Groundwater age represents the time required for water to travel from the point where infiltration reaches the saturated zone to a discharge point in an aquifer such as a water well. Groundwater age can be simulated with numerical groundwater flow models and characterized using environmental tracers. Tritium (a radioactive isotope of hydrogen) is one of several age-date tracers and can be used to qualitatively date groundwater—its presence in groundwater indicates that a component of young water (less than 60 years old) is present in an aquifer. This research compares various several regional estimates of recharge (from available datasets (soil water balance (SWB), empirical water balance (EWB)) and calculated estimates such as chloride mass balance (CMB)); recharge estimates will also be compared to groundwater geochemistry (major/minor ions, field parameters, and trace metals) and qualitative age from tritium dating. Results indicate that areas with higher EWB recharge rates were associated with the distribution of alluvial geomorphology. Pleistocene valley trains had higher EWB recharge rates and correspondingly higher tritium. This is likely due to differences in infiltration, where water is likely recharged more readily in the coarser-grained Pleistocene features. The CMB results indicated, however, that slightly greater recharge occurs in the Holocene alluvium. This was the opposite of what other studies found where CMB recharge was limited to the finer-grained sediments of the Holocene due to elevated chloride concentrations from little to no flushing of salts concentrated during evapotranspiration. The SWB will be incorporated to the overall assessment of recharge estimates and CMB estimates will be improved by using a continuous chloride grid to be included in the calculation. This will likely provide insight where high and low recharge values exist spatially, and which method provides the best overview of recharge in the MRVAA. This will improve confidence where water availability will be an issue—where recharge is relatively low in portions of the MRVAA.
Competencies and training needs in water resource conservation for southeastern extension agents
Year: Authors: McCrary A., Baker B., Burger L., Downey L.
Awareness and knowledge of conservation practices and programs play a major role in conservation practice adoption. The Extension Service is one of many agencies charged with increasing awareness and knowledge of research-based conservation practices, such as those designed to reduce water pollution and impairment. A regional survey of Cooperative Extension Service agents with agriculture and natural resource (ANR) responsibilities was conducted to assess the need for in-service training on water resource conservation topics. The survey was developed based on the Borich model of needs assessment. Landowner's expressed need, agent's perceived importance rating, and agent's perceived ability rating of eleven water resource conservation topics were collected from ANR Extension agents (N = 244) in seven southeastern states. Additional demographic data, including education and experience levels, were collected for comparison of competency ratings between groups. Overall, agents rated the perceived importance of all conservation topics greater than their perceived ability to educate landowners on the same topics, which indicates further need for professional development. Agents rated their perceived abilities highest for explaining fertilizer application and nutrient management, and lowest for pathogen pollution in waterways, soil loss from agricultural fields, and water quality in streams or ponds. Borich mean weighted discrepancy scores, calculated from the average difference between importance and ability ratings, were used to prioritize training needs of all topics for application in professional development initiatives. The highest priority training needs were for topics related to complex interactions and drivers of nonpoint source pollution, such as pathogen pollution in waterways and soil loss from agricultural fields.
Effects of low-external-input and conventional rice cultivation on indicator and pathogenic bacteria presence
Year: Authors: Firth A., Baker B., Brooks J., Davis J.B., Iglay R., Smith R.
Over 800,000 ha of rice is planted in the Mississippi Alluvial Valley (MAV), making it a significant economic crop of the region. Additionally, recognized under the North American Waterfowl Management Plan and the Lower Mississippi Valley Joint Venture, winter-flooded rice fields provide critical habitat for migratory waterbirds. However, wintering waterbird use of flooded rice fields could facilitate pathogen transport in a low-external-input-sustainable-agriculture (LEISA) rice system in the MAV. This study compared two rice farms with different management histories during the winter (conventional and LEISA). Each farm selected for study and received two treatments: 1) unflooded or 2) winter flooded fields. Fecal indicator bacteria (<em>Enterococci, Clostridium perfringens, Salmonella, Campylobacter</em> and <em>Escherichia coli</em>.) were quantified in soil before and after winter flooding and bird fecal matter estimated. Water samples collected from winter flooded fields were tested for <em>Enterococci, C. perfringens</em> and <em>E.coli</em> before fields were drained. Soil analysis results indicated LEISA flooded fields had significantly greater detections of <em>C. perfringens</em> than non-flooded fields. No significant differences were detected between fields in water samples. All observed pathogen rates among treatment were also less than U.S. EPA standards. Results suggest that long-term waterbird stopovers can influence pathogen indicators in soil, however, not at a significant level to pose threat to human and environmental health standards. Nevertheless, because the study was only conducted over one season, it limits the conclusions drawn about wintering bird's potential to contaminate rice fields. Future studies should focus on long-term monitoring of rice fields that harbor wintering birds.
Development of a Boat Traffic Prediction Model Using an Artificial Neural Network
Year: Authors: Rossell W., Ozeren Y., Yasarer H.
Riverbank erosion is a major concern to neighboring inhabitants and the surrounding environment. Boat generated waves can significantly contribute to riverbank erosion in navigable rivers and waterways. Waves created by high-speed vessels can have wave heights large enough to cause significant damage to the riverbanks. A preliminary step to predicting the impact of boat generated waves is to predict local boat traffic. In this study, 8 models for predicting boat traffic along a reach of the Connecticut River were created using a Feed-Forward Artificial Neural Network, considering different combinations of a variety of inputs. Wave data was collected using four capacitance type wave staffs installed at three sites along the study reach, and processed in a deterministic identification model to define boat traffic counts. Weather conditions were categorized using time-lapse videos recorded at the study sites. Other variables for the development of the boat traffic prediction models were the month of the year, day of the month, day of the week, river stage, water depth, logger location, and measured temperature and precipitation data collected at a nearby weather station in Amherst, MA. 7 models were constructed to predict daily boat traffic. 1 model was constructed to predict hourly boat traffic for comparison. This paper presents a comparison of results and the performance of these various models.
Phytoplankton imaging technology for cell identification of Mississippi coastal waters impacted by cyanobacteria during prolonged opening of the Bonnet Carré Spillway in 2019
Year: Authors: Boyette A.D.
The primary objective was to use an advanced plankton imaging system (FlowCAM®) to identify and count harmful cyanobacteria (CyanoHAB) and other phytoplankton cells in Mississippi coastal waters in response to prolonged opening of the Bonnet Carré Spillway (BCS) in 2019. A weekly sampling protocol was conducted from 16 surface stations in the Mississippi Sound from 09 July to 29 August 2019. Although mixed assemblages of diatoms and dinoflagellates were the predominant phytoplankton groups at all stations throughout the sampling period, CyanoHAB genera <em>Dolichospermum</em> sp. and <em>Microcystis</em> sp. colonies were present at elevated (>150,000 colonies L<sup>-1</sup>) concentrations in the western and central Mississippi Sound. Additionally, Chlorophytes, which tended to be freshwater genera (e.g. <em>Pediastrum, Actinastrum</em>), were relatively abundant at stations in the Western Mississippi Sound, but absent in the central and eastern portion of the Sound, suggesting influence of Mississippi River water via the Bonnet Carré Spillway. While the data presented here was useful in determining the extent and proliferation of CyanoHABs, it was not used by environmental managers in a regulatory capacity. However, the impact of CyanoHABs during the summer of 2019 was unprecedented in its extent and pervasiveness along coastal Mississippi. Despite the ecological impacts to Mississippi coastal communities, the BCS remains one of the primary flood control systems on the Mississippi River and will continue to be used as flood mitigation. This underscores the need for a long-term phytoplankton monitoring system to serve as an early warning indicator for harmful algal blooms and other eutrophication processes.
Resource-cost efficiency in catfish farming practices
Year: Authors: Kumar G., Hegde S.
Farm-raised catfish is an important agricultural commodity and an essential component of rural southern economies. Evolution of the U.S. catfish industry, forged by dynamic market forces, has resulted in the development of an array of farming practices. Recent research and commercial yield verification studies on intensive-production systems have identified cost-effective methods for increasing fish production. These systems involve various strategies by increasing aeration horsepower/acre in smaller production ponds as well as constructing new split-pond systems. The relatively high productivity and cost-efficiency of these systems are making them popular foodfish-production strategies in the industry. This comparative study evaluated the resource cost efficiency of nine different catfish production strategies using data from 325 ponds on 38 commercial catfish farms (AR, AL, and MS). The split-pond system using hybrid catfish was the least-cost production strategy, followed by intensively aerated ponds using hybrid catfish, and the multiple-batch system employing channel catfish with increased aeration rates. The results are suggesting that changes in cost structures and economic conditions have changed the degree of profitability of farming practices with more intensive production strategies being more productive and hence more profitable. Additionally, they are also more efficient in their use of land, water (Figure 1), capital, and labor. Although cost efficiency is the driving factor behind intensification, it also allows for achieving improved resource-use efficiency in the industry.
Biobased multifunctional magnetic absorbent from forest residues for non-point pollution water treatment
Year: Authors: Zhang X., Zhang J., Mlsna T.
Non-point pollution (NPP) has been recognized as the leading source of water pollution in the United States, especially Mississippi, threatening water safety and human health. NPP originates from the agriculture and urban stormwater runoff containing major contaminants like nutrients, pesticides, and heavy metals. Today, treatment of NPP water remains a challenge due to no single absorbent can be used to effectively remove all major water contaminants. In this study, we developed a multifunctional biobased magnetic absorbent (MA) from forest residues for the cleaning of various water contaminants including heavy metals (Pb and As) and nutrients (phosphorus and nitrate). The biobased MA was synthesized via a catalytic thermal conversion process with iron nitrate as a catalyst at 1000 °C using a tubular furnace. The structure and morphology of biobased MA were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The performance of biobased MA was tested in terms of heavy metals and nutrients adsorption capacity as a function of time, concentration, and solution pH. This study demonstrates a multifunctional absorbent from renewable resources for NPP water treatment.
Flume experiments in support of multi-beam bed load measurement in rivers
Year: Authors: Wren D., Kuhnle R.A., McAlpin T., Jones K., Abraham D.
Measuring sediment transport in large rivers is problematic, due to high water depth and large bed forms that make it difficult to obtain accurate physical samples near the bed of the river, where most sediment is transported. Additionally, sediment transport is highly variable in space, which means that multiple physical samples must be collected to reach a reasonable estimate of load for a river cross-section. Another problem that compounds error is that bed forms are not consistent over a cross-section, which means that samples from a given cross-section will likely be collected over different parts of bed forms that will yield a wide range of sediment concentrations. In order to overcome these issues, repeated multi-beam acoustic surveys of bed topography can be used to arrive at reach-averaged sediment transport rates. This technique is relatively rapid, does not require physical samples, and accounts for the spatial variability inherent in sand transport. An established methodology for converting repeated bed topography measurements to sediment load is ISSDOTv2, which stands for Integrated Section, Surface Difference Over Time; however, there is a need for establishing error bounds and further developing the methodology. Since it is nearly impossible to collect enough physical samples to validate the method in a river, flume experiments at the National Sedimentation Laboratory were initiated to estimate error bounds for the ISSDOTv2 method, to continue development of the method, and to evaluate its performance in unsteady and spatially variable sediment transport scenarios. Results from the flume experiments, including independent measurements of bed load, suspended load, and bed topography will be presented.
Spatial and temporal patterns of sediment nutrient fluxes in an agriculturally-influenced oxbow lake
Year: Authors: Nifong R.L., Taylor J.M.
Oxbow lakes are an important but understudied component of river floodplain ecosystems and may serve as nitrogen (N) sinks in agricultural watersheds by creating conditions that promote hotspots and hot moments of denitrification. Denitrification can be an important pathway of reactive nitrogen removal, particularly in waterbodies receiving agricultural runoff. In order to examine seasonal and habitat specific patterns of denitrification and sediment oxygen demand, we collected dissolved gas and nutrient samples during 14 different flow-through intact core incubations over the course of a year within Beasley Lake, an oxbow located off the Sunflower River in the Lower Mississippi River Basin (LMRB). Concurrently, we collected field water samples to examine patterns in ambient water quality. We found that dissolved nutrient and nitrogen gas (N<sub>2-</sub>N) fluxes varied in space and time while sediment oxygen demand occurred throughout the year. N<sub>2-</sub>N fluxes were positive in at least one habitat during every sampling event. Dissolved nitrate (NO<sub>3</sub><sup>-</sup><sub>-</sub>N) fluxes from cores were highest from the early summer through the fall, but became minimal during the winter and early spring. In addition to seasonal patterns of NO<sub>3</sub><sup>-</sup><sub>-</sub>N fluxes, we observed positive fluxes of ammonium (NH<sub>4</sub><sup>+</sup><sub>-</sub>N) throughout the year and of phosphate (PO<sub>4</sub><sup>-3</sup>-P) during late summer through the winter from sediments. Field water quality measurements were uniformly low with the exception of the planting season when total suspended sediments (TSS), NO<sub>3</sub><sup>-</sup><sub>-</sub>N, soluble reactive phosphorus (SRP), and total organic carbon (TOC) peaked. Together, these results provide insight into spatial and temporal patterns of nutrient input and removal within agroecosystems in the LMRB.
Phosphorus fluxes resulting from inundated soils in an agricultural watershed
Year: Authors: Yasarer L.M W., Stevens E., Taylor J., Locke M.
Wetting and drying of soils can alter chemical compositions and result in nutrient transformations that lead to more labile phosphorus. Mississippi Delta soils are generally high in phosphorus content and may experience several wet-dry cycles throughout the year, as well as periods of inundation due to flooding conditions. This study was designed to estimate the potential phosphorus fluxes that may occur when dry soils are re-wetted and remain submerged in water for various residence times. Soils/sediments were collected from two locations within five different habitats (cropland, restored cropland (i.e. CRP), forest/riparian wetland, sediment retention pond, and drainage ditches) within Beasley Lake Watershed, Mississippi. Sample locations were selected to include locations that typically experience ephemeral standing water, such as topographic depressions within the cropland, CRP, and forest areas. All soil/sediment samples were dried, ground, and sieved for consistency. Samples were inundated with water and incubated at 5, 15, 25 and 30°C to represent different seasonal temperatures throughout the year. Residence times of 4, 8, 12 and 48 hours were used to estimate the kinetic properties of the phosphorus fluxes. In addition, soils were analyzed for pH, bulk density, and totals of carbon, nitrogen, phosphorus, manganese, calcium, iron, aluminum, and sulfur. Sequential phosphorus extractions of dry, field moist, and flooded soils were also performed to determine how phosphorus was stored in the soil and potential conditions that would release phosphorus into the environment. Preliminary results indicated that forest soils had the highest phosphorus concentrations of all the habitats. Sequential extractions revealed that both drying and flooding the soils increased phosphorus availability.
Effects of herbicide management on Limnobium spongia and water quality
Year: Authors: Lazaro-Lobo A., Turnage G., Ervin G.N.
<em>Limnobium spongia</em> is a free-floating aquatic plant that can produce extensive floating mats and can cause negative ecological, social, and economic impacts. Literature describing effective control measures for <em>L. spongia</em> and possible changes in water quality following herbicide treatment of aquatic plants is minimal. We conducted a mesocosm study to assess the effect of seven herbicides at low and high doses in an effort to control <em>L. spongia</em> while minimizing negative impacts on water quality attributes. We found that low and high doses of imazamox, imazapyr, and flumioxazin herbicides effectively controlled <em>L. spongia</em> initially and during the next growing season, whereas 2,4-D at both rates, as well as high doses of glyphosate and triclopyr initially controlled the species but failed to contain the regrowth of the species during the next summer. Low doses of glyphosate and triclopyr gave poor control of <em>L. spongia</em>, and none of the florpyrauxifen-benzyl rates had any effect on the plants. Furthermore, we found that the increment in light availability after the herbicide-induced death of <em>L. spongia</em> promoted the growth of algae and other photosynthetic organisms in the mesocosms. This led to an increase in dissolved oxygen availability and water column pH. Decreases in plant cover in the mesocosms was correlated with increased electrical conductivity and nitrate concentrations during the first 4 months of the experiment, which potentially could lead to eutrophication issues during plant control efforts at a larger scale, without adequately short residence times in treated water bodies.
Numerical study of pumping induced groundwater flow in vicinity of an alluvial river
Year: Authors: Fang J., Jia Y., Rigby J.R.
Water resource shortage increasingly constraints the development and sustainability of agriculture. Over-pumping has resulted in severe depletions of groundwater (GW) in the Mississippi Delta. To mitigate the problem, an USDA experimental study was proposed to reduce groundwater depletion via pumping from a high-level aquifer and injecting to a lower one. The pumping sites are set to be near the Tallahatchie River in Money County, Mississippi, USA, to take the advantage of water supply from the surface water infiltration. A finite element based numerical model, CCHE3D-GW, was developed in this study to study the drawdown process of the GW affected by the heterogeneous aquifer and surface water in the alluvial river. The numerical model was verified with a vertically averaged 2-D analytical solution considering pumping and surface water infiltration. The model were verified with two sets of meshes, in which 4 and 12 layers were applied in <em>z</em> direction, respectively. A 3-day field pumping test was conducted. The area of the field simulation case is 20.3 ✕ 28.6 km<sup>2</sup>. In this area of the Mississippi Delta, a 40 m thick heterogeneous sandy aquifer is overlaid by a 10 m thick low-permeable aquitard, approximately. Calibrations were conducted using the data of the pumping well and multiple observation wells. The simulation results agree well with the measured pumping data. With the calibrated parameters, a long-term (17 years) pumping was then simulated to better understand the GW balance and distribution in response to the pumping. It is found that the sandy aquifer provides a large portion of the pumped water while the supply from river is limited in the study site.
Changes in Mississippi Sound water quality due to the opening of the Bonnet Carré Spillway
Year: Authors: Moody A., Shiller A.M.
The Bonnet Carré Spillway, a structure that prevents flooding in New Orleans due increased water levels in the Mississippi River, was opened for a total of 122 days in 2019 from February to July. This resulted in a massive release of freshwater into Lake Pontchartrain, which was then funneled into the Mississippi Sound, causing significant chemical and ecological impacts there. Fortuitously, this event occur in the midst of our ongoing sampling campaign aimed at elucidating nutrient distributions and groundwater contributions in the Sound. The impacts from the influx of this freshwater event were mainly focused on the western half of the Sound, closest to outflow from Lake Pontchartrain. Water quality indicators from our time series as well as snapshots from before, during, and after the opening of the Spillway indicate that the western Sound experienced rapid changes in water chemistry. For instance, the average salinity of the Sound decreased from 20 to 5 after the opening of the Spillway. Application of an apparent age model using the ratio of short-lived radium isotopes indicates that the flushing rate of the western Sound during the Spillway opening increased dramatically, changing the physical characteristics of the Sound as well. The high levels of precipitation in the 2019 season led to some elevated nutrient levels across the Sound from increased river discharge.
Groundwater age dating with <sup>14</sup>C, <sup>3</sup>H, and SF<sub>6</sub> to investigate the spatial distribution of recharge rates to the Mississippi River Valley alluvial aquifer
Year: Authors: Gratzer M., Knierim K., Kingsbury J., Wacaster S.
The Mississippi Alluvial Plain (MAP) is the lower part of the Mississippi River floodplain; it overlies the Mississippi River Valley alluvial (MRVA) aquifer. Water-level declines in the MRVA aquifer are of concern. To better characterize the water availability of the aquifer, the spatial distribution of recharge must be well constrained. An approach to investigating the spatial distribution of recharge rates is groundwater age dating: determining the amount of time that has passed since the water became isolated from the unsaturated zone. The U.S. Geological Survey Lower Mississippi-Gulf Water Science Center collected groundwater samples from the MRVA aquifer, which were analyzed for age tracers (<sup>14</sup>C, <sup>3</sup>H, and SF<sub>6</sub>); samples were also collected from the underlying Claiborne aquifer to investigate areas where water may be moving upward into the MRVA aquifer. These age tracer concentrations are used to estimate the distribution of groundwater age in the aquifer at each sample location using lumped parameter models. Multiple age tracers are used because a groundwater sample tends to contain a mixture of water of various ages and each tracer is appropriate for a different time range: up to 30,000 years before present for <sup>14</sup>C, up to 60 years before present for <sup>3</sup>H, and up to 67 years before 2020 for SF<sub>6</sub>. Historical atmospheric <sup>14</sup>C activities range from 97 to 140 pmC. Groundwaters typically have <sup>3</sup>H concentrations less than 10 TU. Historical atmospheric SF<sub>6</sub> concentrations range from 0 to 8.5 parts per trillion (ppt). Generally, the higher the concentration of a given tracer, the younger the water. However, atmospheric <sup>3</sup>H activity varies spatially and temporally, so groundwater 3H activities must be evaluated in terms of the historical atmospheric <sup>3</sup>H activity of the recharge zone in order to estimate groundwater ages. Based on preliminary analysis, <sup>14</sup>C activities (not corrected for dilution) in the MRVA aquifer range from 0.7 to 109.3 pmC; most of the MRVA aquifer has <sup>14</sup>C activities above 60 pmC. Tritium concentrations in the MRVA aquifer range from 0 to 17 TU; most of the MRVA aquifer has <sup>3</sup>H concentrations above 3.5 TU. Sulfur hexafluoride concentrations in the MRVA aquifer range from 0.4 to 9.4 parts per trillion by volume (pptv); most of the MRVA aquifer has SF6 concentrations above 2.4 pptv. The <sup>14</sup>C activity in the MRVA aquifer is lowest in Mississippi County, AR, and highest in Butler County, MO, and Iberville Parish, LA. The spatial distributions of <sup>3</sup>H and SF<sub>6</sub> are very similar to each other. The spatial distribution of <sup>14</sup>C is similar to <sup>3</sup>H and SF<sub>6</sub> except for a group of well locations, in a north-south orientation from the bottom of the Grand Prairie region of Arkansas to the top of Louisiana, where <sup>14</sup>C is high and <sup>3</sup>H and SF<sub>6</sub> are low. The lowest (oldest) and highest (youngest) SF<sub>6</sub> concentrations lie in areas with similar, relatively high (young) <sup>14</sup>C activities, probably due to the finer temporal resolution of SF<sub>6</sub> concentrations for young groundwater than that of <sup>14</sup>C activities. The highest <sup>3</sup>H activity lies in an area with high (young) <sup>14</sup>C activity, and the lowest <sup>3</sup>H activity is the same location as the lowest (oldest) <sup>14</sup>C activity. The lowest (oldest) SF<sub>6</sub> concentration was collected from a location with a low <sup>3</sup>H activity and the highest (youngest) SF<sub>6</sub> concentration was collected at a location with a high <sup>3</sup>H activity. Results of the lumped parameter models will be presented.
Sensor-based irrigation scheduling
Year: Authors: Sui R.
Though annual precipitation in the Mississippi Delta is approximately 130 cm, only about 18% of the precipitation occurs during June to August when crops require a large quantity of water to grow. Furthermore, heavy rainfall in summer causes extensive amounts of runoff, resulting in only a small amount of the precipitation infiltrating into the soil for crop use. Uncertainty in the amount and timing of precipitation is one of the most serious risks to the crop production in this region. To reduce the risk and increase farming profit, irrigation acreage has been increasing. Groundwater pumped from Mississippi River Valley alluvial aquifer provided about 95% of the water used for irrigation and fish culture in the Mississippi Delta. Due to the large withdrawals, water levels of the aquifer have significantly declined. It is necessary to develop improved water management tools for sustainable agriculture in the region. Advanced irrigation scheduling technologies can increase water use efficiency and reduce the groundwater withdrawal in irrigation. A sensor-based irrigation scheduling (SBIS) method was developed and evaluated for irrigation management. Soil moisture sensors were installed in soil profile at three depths (15 cm,30 cm, 61 cm). Soil volumetric water content (VWC) was automatically measured by the sensors in a time interval of an hour during crop growing season. The VWC data were transferred through a wireless sensor network so that the data could be accessed online. Sensor-measured VWC at all the depths were interpreted using a weighted average method to reflect the status of soil water in plant root zone. Irrigations were triggered as the sensor-measured VWC dropped down to a threshold which was determined according to the soil properties. An antenna mounting device was developed and implemented to avoid the soil moisture measurement being interrupted by some agricultural activities such as applications of pesticide and fertilizer. The SBIS method has been used in cotton, corn, and soybean crops, and it indicated that this method could be a useful tool in irrigation management.
Open-source hardware and software offer options for development of monitoring systems for water management, agricultural, and environmental applications
Year: Authors: Fisher D.K.
Information is needed in order to study, monitor, and understand any process or event. Advances in electronic technologies, software, and communications infrastructures have resulted in a variety of new and inexpensive monitoring capabilities for research and production applications. A new generation of microcontrollers offers high-speed, low-voltage, energy-efficient, 32-bit operation, and supports programming in multiple languages (C/C++, Python). The increasing variety of solid-state sensors (environmental, multispectral) and auxiliary components (data storage, GPS/RTK) enables development of unique automated sensing, monitoring, and control systems. Remote data communications are enhanced via communications (LoRa wireless, LTE Cat-M1 cellular) networks, and integration with internet-based services allows rapid data transfer and always-available access to and sharing of data. These emerging technologies are enabled by application of open-source hardware and software, which offer advanced tools and capabilities and are freely available for anyone to use, develop, and modify. Open-source hardware and software options will be discussed, and examples of monitoring systems that have been developed will be presented to demonstrate the accessibility and usefulness of these development tools.
Can volunteer flooding of cropland after harvest reduce contaminant export in the Mississippi Delta?
Year: Authors: Moore M.T., Taylor J.M., Rigby J.R.
The Mississippi Delta is well known for its fertile landscape, helping to feed a growing nation and world. In addition, the Mississippi Flyway is a vital bird migration path for waterfowl enthusiasts. These two worlds often intersect about three months after harvest, as many farmers will voluntarily flood post-harvest fields for waterfowl habitat and hunting. Recent efforts have suggested that an earlier voluntary flood, within one month of harvest, provides critical stopover habitat for wading birds with an earlier migration pattern than ducks and geese. To that end, a collaborative research project was established on a farm in Sunflower County, Mississippi, in conjunction with Delta Windbirds. Six identical, adjacent fields (30 acres each) were chosen for this project. Three fields were flooded for migratory bird habitat in mid-September 2019, while the remaining three fields were left fallow and unflooded, post-harvest. Grab samples for water quality were collected weekly/biweekly on ten occasions in the flooded fields, while automated samplers collected any storm runoff from unflooded fields during the nearly five month project. A comparison of water quality parameters (nutrients and solids) in flooded fields suggests the mitigative capacity of the flooding practice, preventing excessive nutrients from entering receiving water bodies and further exacerbating downstream water quality impairments. Limited runoff data from unflooded fields corroborates this suggestion. While water quality is only part of this research assessment, taken in context with other study components, the practice of early volunteer flooding post-harvest can provide critical wetland functions from which farmers and conservation managers can utilize to improve water resources in the Mississippi Delta.
The Effects of Backwater Flooding on Aquatic Health in the Yazoo Backwater Area from Low Dissolved Oxygen Concentrations
Year: Authors: Johnson B.S.
Dissolved Oxygen (DO) has long served as one of the primary indicators of aquatic health in aquatic ecosystems. The EPA has defined adequate concentrations of DO for fish to be greater than 5.0 mg/L for warm water streams. A water quality monitoring program was initiated in 2004 in the Yazoo Backwater Area (YBA) by the Vicksburg District which extended through 2019. The program documented the reduction in DO in the lower Steele Bayou and Big Sunflower Basins for prolonged periods during backwater flood events. For the first few weeks of a typical backwater flood, diffusion becomes the principal mechanism for oxygen transfer into the water column at the surface. This DO transfer condition compounded with the increase Sediment Oxygen Demand (SOD) exerted on the unmixed water closer to the bottom allows for severe DO depletion. Because of this, limited fish species diversity has been observed in the YBA.
Yazoo Backwater Area Wetlands—What's New?
Year: Authors: Johnson D.R.
The historic 2019 Yazoo Backwater flood renewed interest in the Backwater Pump Project. Mississippi's Senators and Congressmen applied pressure to the EPA to reverse the 404 C veto. New information has greatly altered the extent and possible impacts to wetlands in the project area. The use of shallow ground water monitoring wells changed the source of water creating the wetlands, and the use of LIDAR DEM altered their extent.
Cover Crop and Tillage Influence on Growth, Yield, and Plant-Water Status of Cotton and Sorghum
Year: Authors: Dhakal M., Locke M., Reddy K.
Improved and sustainable soil and crop management practices that reduce crop water use, optimize cotton and sorghum yields, and improve vadose zone water quality is a challenge in the Mississippi alluvial plain. A plot scale long-term agro-ecosystems research (LTAR) experiment was established in October 2018, Stoneville, MS, to examine the influence of tillage [no-tillage (NT) and conventional tillage (CT)], cover crop treatments [no-cover (NC) and cover crop (CC) (Austrian pea, <em>Pisum sativum</em> L.)], and crop rotation [cotton (<em>Gossypium hirsutum</em> L.) and sorghum (<em>Sorghum bicolor</em> L.) (monocultures and rotation)] on crop cover, biomass, yield, water use efficiency, and soil N and organic matter dynamics. Data were collected from June to October 2019 pertaining to canopy cover, leaf area, vegetative mass, yield, and leaf water potential. Soil-water monitoring using capacitance probes to a 122-cm depth was begun in December 2019 and will be continued throughout the 2020 cash crop season. In this establishment year, preliminary results showed no effect of CC and tillage treatments on crop ground cover during vegetative growth from June to August (<em>P</em> > .05), however, weed cover was greater in NT (6.4%) than CT (3.8%) treatments (<em>P</em> < .05). Also, LWP wasn't affected by CC and tillage treatments (<em>P</em> > .05). Although the panicle density of sorghum was greater in CT-NC (16 panicles m<sup>-2</sup>) than CT-CC (11 panicles m<sup>-2</sup>), grain yield did not differ between conventional (CT and NC) and conservational practices (NT and CC) (<em>P</em> > .05) with a mean yield of 6.6 Mg ha<sup>-1</sup>. Similarly, cotton lint and seed yield (<em>P</em> > .05) were unaffected by the treatments, averaging 1.78 and 4.12 Mg ha<sup>-1</sup>, respectively. No-till cotton and sorghum management practices in conjunction with CC system may sustain productivity by producing comparable biomass and yield to conventional methods, but these results are considered preliminary in this first year of establishment.
Evaluate the effect of BMPs on hydrology and water quality at field scale
Year: Authors: Risal A., Parajuli P.
In order to implement and regulate water resource management plans in a watershed, it is required to apply some Best Management Practices (BMPs) and evaluate their effects on hydrologic behavior and water quality. Field scale watershed model such as Agricultural Policy/Environmental Extender (APEX) can be applied to access the effect of such BMPs. APEX was applied to a sub-basin of the Big Sunflower River Watershed (BSRW). Calibration and validation of APEX for streamflow was conducted using the flow output from the calibrated Soil and Water Assessment Tool (SWAT) model for BSRW and that for sediment yield, Total Nitrogen (TN), and Total Phosphorous (TP) were conducted using observed data obtained every fifteen days from 2014 to 2016 for two locations within the sub-basin. Modeling scenarios such as crop rotation, tailwater pond, and vegetative filter strips (VFS) were applied and their effects in reducing runoff, sediment yield, TN, and TP concentration were evaluated. A significant difference in the amount of surface runoff, sediment yield, and nutrients concentration were observed for different BMP scenarios. The simulation results obtained from this study will provide a better idea to other modelers and decision makers in formulating decision regarding BMP implementation and proposing a suitable field scale BMPs in the reduction of surface runoff, sediment, and nutrient yield.
Runoff Water Quality under Conservation Management in Mississippi Corn Production
Year: Authors: Spencer D., Krutz J., Gholson D., Locke M., Henry B., Golden B.
Row-crop agriculture in the delta region of Mississippi is a major contributor to groundwater decline and surface waterbody impairment. Conservation management practices such as cover crops and no-tillage may improve irrigation efficiency and decrease contaminant runoff, thus promoting sustainable stewardship of both ground and surface water resources. The effects of cover crops and tillage system on runoff water quantity and quality under simulated rainfall and furrow irrigation were evaluated on a Commerce very fine sandy loam (fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquepts) at Stoneville, MS from 2017 to 2019. Under furrow irrigation, no-tillage decreased runoff volume and increased furrow advance time in one of three and two of three years, respectively. Other than crimson clover in one of three years, cover crops did not reduce runoff under furrow irrigation. No conservation practice decreased runoff under simulated rainfall. In 2017 and 2018, cover crops did not have an effect on water quality. No-tillage improved turbidity, but also increased certain nutrient concentrations and loads. Water quality results from 2019 will be presented as well.
Investigation of Reduced Herbicide Rates and Tank Mixes Applied Via Submersed Injection for the Selective Control of Cuban Bulrush (<em>Oxycaryum cubense</em>)
Year: Authors: Turnage G., Byrd J.
Cuban bulrush (<em>Oxycaryum cubense</em>) is a perennial invasive aquatic plant species native to South America that is spreading across the Southeastern US. Cuban bulrush can block boat launches, impede navigation along river channels, negatively affect drainage canals, and degrade fishery habitat by lowering dissolved oxygen under plant mats. Cuban bulrush is capable of outcompeting and displacing native and other invasive species for resources thereby disrupting ecosystem processes. During initial colonization, it exists as an epiphytic species utilizing other aquatic plants or structures for habitat. Limited data exist concerning effective chemical control (herbicides) methods for controlling Cuban bulrush. This project was conducted over two years to 1) screen potential herbicides for selective control of Cuban bulrush (year 1) and 2) investigate tank mixtures of herbicides active on Cuban bulrush for selective control (year 2). In year 1, herbicides were identified that provided short-term selective control of Cuban bulrush grown with American lotus; herbicides were applied at the maximum rate allowed. No herbicide provided long term reduction of Cuban bulrush or American lotus. In year 2, reduced rates (half the maximum label rate) and tank mixtures of two systemic (triclopyr and fluridone) and two contact (flumioxazin and carfentrazone-ethyl) herbicides from year 1 were examined for control of Cuban bulrush and two native plant species, cattail and hardstem bulrush. Emergent Cuban bulrush was reduced 92% by triclopyr, 88% by carfentrazone-ethyl, 100% by triclopyr+flumioxazin, and 100% by triclopyr+carfentrazone-ethyl when compared to reference plants at 8 weeks after treatment (WAT). At 44 WAT, all treatments deliver greater than 94% control of Cuban bulrush compared to reference plants. Submersed Cuban bulrush was reduced 86% by triclopyr and 93% by triclopyr+flumioxazin when compared to reference plants at 8 WAT. At 44 WAT, all treatments delivered greater than 93% control of Cuban bulrush when compared to reference plants. In year two, herbicides did not reduce biomass of native plants at eight weeks after treatment (WAT). Hardstem bulrush was not affected by herbicide treatments at 44 WAT while cattail biomass was reduced by multiple treatments. These data suggest that triclopyr alone and in combination with flumioxazin can selectively control both emergent and submersed Cuban bulrush tissues over the short-term, but any herbicide or herbicide combination used here can deliver long term control. These treatments provided selective long-term control of Cuban bulrush when growing with American lotus and hardstem bulrush but not cattail.
Groundwater recharge from an oxbow lake-wetland system in the Mississippi Alluvial Plain
Year: Authors: Gratzer M.C., Davidson G.R., O'Reilly A.M., Rigby J.R.
The Mississippi River Valley Alluvial Aquifer ranks among the most overdrafted aquifers in the United States due to intensive irrigation. Concern over declining water levels has increased focus on understanding the sources of recharge. Numerous oxbow lakes overlie the aquifer that are often considered hydraulically disconnected from the groundwater system due to fine-grained bottom sediments. In the current study, groundwater levels in and around a 445-ha oxbow lake-wetland in Mississippi were monitored for a 2-year period that included an unusually long low-water condition in the lake (>17 months), followed by a high-water event lasting over 4 months before returning to earlier low-water levels. The high-water pulse (>4 m rise) provided a unique opportunity to track the impact in the underlying alluvial aquifer. During lowwater conditions, groundwater flowed westward beneath the lake. Following the lake rise, groundwater beneath and near the perimeter responded as quickly as the same day, with more delayed responses moving away from the lake. Within 2 months, a groundwater mound formed near the centre of the oxbow (>3 m increase), with a reversal in the local hydraulic gradient towards the east. Flow returned to a westward gradient when the lake level dropped back below 0.3 m. Analysis of precipitation and nearby river stage could not account for the observed behavior. Recharge to the aquifer is attributed to rising water levels spreading over point bar deposits and into the surrounding forested wetlands where preferential flow pathways are likely to exist due to buried and decomposing tree remains. An earlier study in the wetland demonstrated an increasing redox potential in isolated zones, consistent with the existence of preferential flow pathways through the bottom sediments (Lahiri & Davidson, 2020). Retaining high-water levels in oxbow lakes could be a relatively low-cost water management practice for enhancing aquifer recharge. <a href="https://doi.org/10.1002/hyp.13680" target="_blank" aria-label="Download https://doi.org/10.1002/hyp.13680">Download full article</a>
Response of the aquatic weeds Crested Floating Heart and Watershield to varying herbicide rate at different application periods
Year: Authors: Turnage G., Byrd J.
Watershield (<em>Brasenia schreberi</em>) and Crested Floating Heart (CFH; <em>Nymphoides cristata</em>) are two perennial aquatic plant species that are problematic/weedy in the Southeastern US. Watershield is a native species while CFH is an invasive species from Asia. Both species can negatively affect human and ecosystems processes in aquatic habitats. Both are capable of outcompeting and displacing native plant species for resources thereby disrupting ecosystem processes. Limited data exist concerning effective chemical control (herbicides) methods for both species. This project was conducted to 1) determine if a new liquid formulation of flumioxazin was effective at controlling either species at high and low rates and 2) determine if timing of herbicide application (early vs. late season) could enhance control of either species. Both WS and CFH plants were established in mesocosms at MSU and allowed to grow for one month prior to herbicide applications. Herbicide residues were in contact with target plants for 24 hours then herbicide treated water was drained off and mesocosm tanks refilled. At 4 weeks after treatment (WAT), none of the herbicide treatments had reduced aboveground (AG) biomass of watershield during both application trials when compared to reference plants. However, watershield belowground (BG) biomass was reduced by <90% by both granular rates in the early season trial; in the late season trial, the low rate of granular flumioxazin had an increase (573%) in watershield BG biomass while other treatments were not different from the references. Herbicide treatments had no effect on CFH biomass or propagule production (daughter plants) at either time period. However, there was a difference in CFH BG biomass among herbicide treatments (while none were different from the reference) at the early season application. Also, while not different from references there were no CFH propagules produced by either low flumioxazin treatment during the late season trial; lack of statistical significance is likely due to the low number of replicates (3) in each treatment used for this trial. Future work should utilize more replicates and herbicide rates as well as explore longer exposure times.
Groundwater quality and age to address water availability in the Mississippi River Valley Alluvial Aquifer
Year: Authors: Killian C., Bussell A., Knierim K.J., Wacaster S., Gratzer M.
Existing and newly collected water quality data has been used to better characterize sources of water and improve the hydrogeology of the Mississippi River Valley alluvial (MRVA) aquifer, located within the Mississippi Embayment (MISE). Groundwater with high concentrations of metals, including iron and manganese, and areas of high salinity limit groundwater availability for irrigation, public supply, and domestic use. Water-availability issues within the MRVA aquifer have generated the need to improve water-budget estimates of existing regional groundwater-flow and three-dimensional machine-learning models. Groundwater age tracers, including tritium, carbon-14 (<sup>14</sup>C), sulfur hexafluoride (SF<sub>6</sub>), and noble gasses, were collected as part of the United States Geological Survey (USGS) Mississippi Alluvial Plain (MAP) regional water availability study help characterize sources of water to the MRVA aquifer. Sources of water to the MRVA aquifer include surficial recharge and upwelling from saline water from deeper hydrogeologic units. To map surficial hydrogeologic units of the MISE, the USGS is conducting a regional Airborne Electromagnetic (AEM) survey to detect changes in resistivity of subsurface units; however, the spatial and vertical distribution of groundwater specific conductance must be characterized to accurately interpret changes in resistivity. Accurate characterization of hydrogeologic units, especially where MISE units subcrop beneath the MRVA, will help identify drivers of groundwater quality and recharge of the MRVA aquifer. The results from this effort will help interpret data from the AEM survey, support three-dimensional machine-learning models of specific conductance and recharge-rate estimates as a part of the water budget for the MAP, and help to characterize areas where potential upwelling from deeper saline units may impact the availability of fresh water in shallower aquifers.
Modifying the DRASTIC method to create an Aquifer Recharge Potential Map for Alabama
Year: Authors: Guthrie G., Hastings Puckett M., Hastert G.
The DRASTIC method was developed by the USEPA in 1985 to model groundwater contamination potentials for diverse hydrogeological regions. The method combines seven factors: <em>D</em>epth to water table, <em>R</em>echarge (net), <em>A</em>quifer media, <em>S</em>oil media, <em>T</em>opography, <em>I</em>mpact of vadose zone, and <em>C</em>onductivity (hydraulic), which are rated and weighted to produce a numerical value, the DRASTIC Index, which provides a relative assessment of an area's contamination potential.<br /><br /> The DRASTIC conceptual model contains an intrinsic component comprising relatively invariable factors (aquifer media, soil media, topography, and aquifer conductivity) and an acquired component comprising variable factors (net recharge and vadose zone impact). Land use/land cover was not included in the original DRASTIC method. A modification to the DRASTIC methodology has been used to produce an Aquifer Recharge Potential map for Alabama using an intrinsic/acquired factor model. The intent of the map is to show the potential of an area for groundwater recharge given a set of acquired conditions based on a Recharge Potential Index (RPI). The map combines intrinsic factors (soils, topography, and aquifer hydraulic conductivity) to create an intrinsic properties base map. Variable factors (net recharge, depth to water table, and land use) can then be added to create the potential recharge map. These factors to produce maps that reflect changing temporal conditions. The Analytic Hierarchy Process (AHP) is used to modify the weighting system to create a more accurate RPI. The AHP uses a pairwise comparison matrix to evaluate the relative importance of multiple criteria by generating a consistency index that measures the inconsistency of judgements used in the developmental model. The map is intended to provide stakeholders a tool for evaluating the potential effects of land use changes, drought, and flooding for groundwater availability in Alabama.
Geochemical Assessment of Trace Metals from Varied Aquatic Systems in Southern USA
Year: Authors: Paul V., Vattikutti S., Sankar M.S., Dash P., Berry M., Arslan Z.
Metal pollution in water bodies is a matter of international urgency, owing to the many associated toxicological and environmental issues. Sediments in water bodies serve as an important storage point for many of these metals and could release the adsorbed/absorbed ions back to the water under favorable conditions. Comparing the concentration of metals in different aquatic bodies will help to evaluate the accumulation and distribution characteristics within these systems. We investigated trace metal accumulation in sediments obtained from different aquatic systems in the state of Mississippi to evaluate and compare their pollution and enrichment indices. Sediments from five different aquatic systems; agricultural ponds, man-made reservoir, river, swamp and coastal marine environment including bay region, were collected. Following total digestion of the sediments, the concentrations of eleven trace metals (Cr, Co, Cu, Zn, As, Se, Cd, Sb, Hg, Pb, and U) were analyzed using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The coastal and agricultural ponds samples showed the highest degree of anthropogenic modification (enrichment factor >10), especially for metals Se, U, Hg, and Pb. The metals Hg and Pb were highly enriched in sediment samples of all five environments. The pollution load index calculated for each system showed that the agricultural ponds were progressively deteriorated with respect to the sediment quality (value >1). The metals Cd and U showed high contamination factor (>6) in one agricultural pond sample, indicating moderate to severe contamination. Overall, our data indicate that sediments in the river, forest and man-made reservoir systems contain relatively fewer metal pollutants when compared to agricultural ponds and coastal regions. Both agricultural ponds and coastal regions serve as collection points for fertilizers, and other chemicals that contain metals, thereby explaining the trend observed. The research provides one of the first studies comparing sediment quality within different water bodies and will help in future studies to narrow remediation efforts.
Evaluating the Influence of Geophysical Data Integration for the Shellmound Inset Groundwater-Flow Model of the Mississippi Alluvial Plain
Year: Authors: Guira M.N., Peterson S.M., Traylor J.P.
The U.S. Geological Survey (USGS) Mississippi Alluvial Plain project has been updating groundwater-flow models of the Mississippi Embayment and Mississippi River Valley Alluvial aquifers to provide stakeholders with tools that can be used to support water resources management decisions. Groundwater withdrawals from the Mississippi River Valley Alluvial aquifer have been vital to support agricultural production in the region near Shellmound, Mississippi, but substantial groundwater-level declines in the region have caused concerns for long term sustainability of the aquifer. Stakeholders are considering a number of actions to mitigate the groundwater-level declines, including managed aquifer recharge through riverbank filtration, whereby groundwater will be extracted near the Tallahatchie River and injected into the aquifer. High resolution airborne electromagnetic (AEM) survey data were collected to improve the understanding of the subsurface hydrostratigraphy in the study area, and for integration into a groundwater-flow model. A transient groundwater-flow model was constructed using MODFLOW6, the latest USGS modular three-dimensional finite-difference groundwater-flow model. The active model domain covers an area of about 1,000 square kilometers in northwestern Mississippi. The AEM data were processed at multiple vertical resolutions to build MODFLOW6 models with various layering configurations, including a single layer, a 5-meter constant layer thickness, and a 10-meter constant layer thickness. All three versions of the model use the same hydrologic input data and are calibrated against equivalent calibration targets. Simulated outputs along with calibration data will be compared to determine the influence of increased layer detail on model calibration, to the extent supported by the available observation data.
Field testing and simulation of vadose-zone recharge wells as an artificial recharge method in the Mississippi River Valley Alluvial aquifer
Year: Authors: O'Reilly A.M., Kwak K., Rigby J.R.
Past studies in the Delta region of Mississippi document substantial groundwater losses from the Mississippi River Valley Alluvial aquifer (MRVAA) and indicate limited potential for infiltration and recharge due to fine-grained, low permeability surficial sediments. An artificial recharge technique not dependent on permeable surficial soils is a vadose-zone well. A vadose-zone well is a borehole, which does not intersect the saturated zone, excavated through low permeability surficial sediments and completed as a dry well into underlying higher permeability sediments. Water directed to the well flows by gravity into the native sediments of the vadose zone.<br /><br /> Data were collected at a field site near Ruleville, Mississippi, consisting of four vadose-zone wells, six monitor wells, and one production well. From pumping test data, transmissivity of the MRVAA at the site is 5,700 m<sup>2</sup>/day and storativity is 0.33. Despite being considered an unconfined aquifer, a distinct inverse correlation existed between barometric pressure and water level in the wells, indicating a barometric efficiency of approximately 60%. During a 50-hour injection test, well recharge caused small water-table rises ranging from 4 cm at the nearest monitor well (6.1 m) to 1 cm at the most distant well (35 m). Small rises likely are due to the high hydraulic conductivity of the MRVAA, vertical heterogeneity, screen location of the monitor wells, or some combination of these factors. Laboratory analyses included measurement of saturated hydraulic conductivity of vadose-zone soil cores. Additionally, wetting/draining curves were determined using the hanging water column method, representing some of the first measurements of capillary hysteresis in the Delta.<br /><br /> A three-dimensional numerical variably-saturated model of four vadose-zone wells was developed using HYDRUS-3D software. Pressure-head changes were reported at five observation nodes located 0.17 m below the water table. Head rise beneath the vadose-zone well was 2 cm and dropped to 0.6 cm at a distance of 6.3 m. Different water-table responses between the field test and model simulations are likely due to differences in the amount of injected water and lack of data on aquifer heterogeneity relative to monitor well screen locations. A total of 272 m<sup>3</sup>/day of water was injected during the field test, whereas only 88 m<sup>3</sup>/day was simulated in the HYDRUS model. This research provides understanding of the hydraulic properties controlling operation of vadose-zone wells. Challenges include clogging leading to limited well life and potential water-quality impacts caused by source water for the vadose-zone well bypassing shallow soil-aquifer treatment processes.
Assessing surface water use for irrigation in the Delta and its effects on groundwater
Year: Authors: Brock M., Tagert M.L., Paz J.O., Krutz J.
Agricultural production in the Mississippi Delta region relies heavily on groundwater for irrigation due to insufficient rainfall during the summer growing season between May and September. As of 2019, more than 20,000 groundwater well permits for agriculture have been issued in the Delta. The Mississippi River Valley Alluvial Aquifer is the shallow subsurface aquifer underlying the Mississippi River Basin, and concerns persist over the dependence on and future supply of water in this aquifer. Surface water sources for irrigation include on-farm water storage (OFWS) systems implemented as a conservation practice for nutrient reduction with cost assistance from the NRCS Mississippi River Basin Healthy Watersheds Initiative. Consisting of storage ponds and tailwater recovery ditches that intercept irrigation and precipitation runoff from adjacent fields, these systems started being constructed in Mississippi in 2008 and have grown in prevalence in the following years. The goal of this study was to quantify the role of OFWS systems in irrigation and as an alternative to groundwater by examining the inventories of OFWS systems for selected years between 2007 and 2018. The size and number of OFWS systems were identified and recorded based on the geospatial data layers containing digitized polygons of the ditches and ponds that make up these systems. Inventory results show an increase in surface water storage from 22.37 ha in 2007 to 651.61 ha in 2018. Next, interpolated maps of saturated aquifer percentages were created using groundwater levels measured by the Yazoo Mississippi Delta Joint Water Management District and aquifer thickness values from the United States Geological Survey. These interpolated layers and inventories are being used to evaluate and define relationships and trends between surface water use and groundwater use for agricultural irrigation. This presentation will compare trends in groundwater decline between land with supplemental irrigation using surface water and land solely irrigated with groundwater.
A crop modeling approach to analyze in-field soil moisture variability
Year: Authors: Hodges B., Paz J.O., Tagert M.L., Reginelli D.
Site-specific irrigation decisions require information about variations in soil moisture throughout the rooting depth actively being used by the crop. An increasing number of producers are using soil moisture sensors to make irrigation decisions, and it has been shown that soil moisture sensors can reduce water usage without reducing yields, which also conserves money. This three-year study uses sensors and crop modeling to evaluate the spatio-temporal variability of soil moisture across an 18-ha production field in a corn/soybean rotation. A 55 m by 55 m grid was laid on the field, which resulted in 44 sampling points that fell either underneath the center-pivot irrigation or the end gun. At each point location, two Watermark granular matrix sensors were installed at depths of 30.5 and 61cm. Analysis of soil samples collected in year one of the project revealed fairly homogeneous soils across the field with silty clay loam as the major soil type and only eight percent silt loam. Plant height and leaf area index (LAI) were measured weekly at each of the 44 sampling points, which resulted in eight measurement dates during the 2018 growing season of the soybean crop. A digital elevation model was also used to log the elevation at each point location. The crop variables were inserted into the CROPGRO crop model in the Decision Support System for Agrotechnology Transfer suite of models to calibrate and predict soybean growth and water use in the field. The soil moisture values will also be inserted into the model when they are converted from soil matric potential to volumetric water content. The model will be run for every grid in the field to predict whether there should be a different irrigation schedule for parts of the field. In this presentation, the results from four grids will be discussed.
Mississippi Water Stewards: Development of a Statewide Citizen Water Monitoring Program
Year: Authors: Logan K., Baker B., Sparks E., Dominguez M., Cordova S.R., Braman A.
Mississippi has ecosystems that reside in three Gulf of Mexico (GOM) watersheds; it also faces several environmental and economic barriers at local scales that limit water monitoring and protection capacity, including underserved populations and a thriving agricultural industry. To address the protection of Mississippi's local water resources and the GOM, Mississippi State Extension Service personnel have partnered with the Alabama Water Watch Program and the Pearl Riverkeeper program, with funding from the U.S. Environmental Protection Agency to develop infrastructure for the first statewide citizen based-water monitoring and education program. The Alabama Water Watch (AWW) and Global Water Watch (GWW) Programs have been successfully applying and refining their model of community-based watershed stewardship for more than 25 years, which has gained them national and international recognition in the realm of volunteer monitoring. The Mississippi Water Stewards (MSWS) program will implement EPA-approved quality assurance plans for water chemistry and bacteriological monitoring, as well as develop plans for biomonitoring and a youth education program in three pilot watersheds in Mississippi. The implementation of MSWS will be achieved by adopting the Alabama Water Watch model. Sound development and piloting of the MSWS program will include adaptation of an administrative infrastructure, development of MSWS water monitoring manuals, facilitation of four citizen monitor certification workshops, development of a Training of Trainer (TOT) manual and the facilitation of one TOT workshop. We anticipate outcomes of this project to include the certification of 60 trained monitors, 15 MSWS trainers, the collection and submission of approximately 1000 data records by citizen monitors, development of a youth monitoring curriculum, educator workshop, and engagement of youth in watershed stewardship and monitoring by trained educators using MSWS 4-H curriculum. Protection of water resources through education and outreach to citizens will build transparency and public participation in the protection of the states' unique water resources and ecosystems, thereby protecting the GOM, fostering community involvement, and water resource protection. The MSWS program will empower citizens to use their data to bring about positive changes in their communities by influencing water policy, implementing watershed management plans, and educating others.
Applying a Watershed Scale - Ecosystem Services Framework to Improve Stakeholder Engagement and Increase Participation of African Americans in Ecological and Environmental Sciences
Year: Authors: Dugo M.A.
We introduce an exploratory science education research and watershed monitoring program, funded by the National Science Foundation, to improve stakeholder engagement and increase the participation of African Americans in ecological and environmental sciences. The curriculum will combine a citizen science engagement strategy with applied skills in environmental STEM disciplines, using both field and laboratory based research activities. Our place-based framework is designed to characterize watersheds at the basin level and is inclusive of socioeconomic integration. The ecosystem services framework will be utilized to highlight socio-environment interrelations, while concurrently emphasizing the importance of biodiversity and reinforcing cultural connections to the environment. A compliment of activities are proposed including, an undergraduate summer enrichment program, year round environmental monitoring for undergraduate and graduate students, and community outreach. Our curriculum will utilize publically available data sources including, Google Earth Pro, EnviroAtlas, 303d listed streams, TMDL reports, and census data, to identify relevant environmental, social and economic factors necessary for the holistic management of natural resources. Water quality will be correlated to biodiversity metrics obtained through field collections, the use of biological collection databases, and information for species of conservation concern. This project emphasizes the relationship between values, identity, and interest, to foster a deeper connection to the environment. In addition to impacting the STEM environmental workforce, the citizen science component of this project is predicted to empower student participants and proximal communities toward greater social justice and equity, as related to natural resources.
Fog Harvesting with Vertical Harp Structure
Year: Authors: Azeem M., Wiener J.
The shortage of clean water in some parts of the world has compelled the researchers to find the alternative fresh water resources. On the coastal side, fog stands out alternative water sources because fog water can be harvested in large quantity without consuming energy. However, fog collection has attracted the interest in recent years resulting in a large body of work focused on improving the design of fog collectors. We designed a two-layer harp structure in comparison with traditional Raschel mesh being used from many years. Polypropylene (PP) monofilament was used as collector element. It was reported that two-layer harp collectors can resolve many of the problem incorporated with single-layered collectors, including clogging. Fog water collection rate by this technique was measured double than Raschel mesh. The diameter of monofilament and distance between the two layers was also optimized with experimental and theoretical work. The results showed that, the distance between the adjacent elements of the harp was <u>></u> 1mm to avoid from clogging. When optimized, the Raschel mesh collector yielded half of the fog water as compared to our two-layer harp design under laboratory conditions. The basic idea is to increase the efficiency of fog collector for commercial purpose; therefore it was proposed the cylindrical textile monofilaments.
Voluntary flooded agriculture systems generate macroinvertebrate food resources for waterbirds and shorebirds in the Lower Mississippi River Basin
Year: Authors: Bacon P., Taylor J.M., Testa III S., Rigby J.R.
Voluntary flooding of post-harvest agriculture fields is a management practice that can be utilized to help mitigate permanent loss of wetlands and decrease losses of fertile soil associated with heavy winter rainfall. These inundated fields may promote positive community responses that increase habitat suitability for wetland species such as migratory waterbirds and shorebirds. For many migratory shorebird species, aquatic macroinvertebrates are a primary diet component vital to meeting the energetic requirements necessary for daily activity, as well as seasonal migrations. In order to utilize crop systems as temporary seasonal conservation management units, aquatic macroinvertebrate community structure and trophic stability must be established quickly. The focus of this study was to evaluate and quantify macroinvertebrate community structure and secondary production in post-harvest voluntary flooded agriculture fields. Three post-harvest corn fields, located in the Mississippi Delta were selected, were inundated with surface water from a tailwater recovery storage reservoir. Macroinvertebrate diversity and richness along with secondary production of dominant taxa were investigated over a five month period. Macroinvertebrates were quantitatively collected weekly to bi-monthly. Samples were brought back to the laboratory for processing and identification to determine species richness and diversity. Secondary production estimates were calculated for the dominant taxa, nonbiting midge larvae (Diptera: Chironomidae), using the size-frequency method. Macroinvertebrate diversity, density, and overall production of dominant taxa greatly increased after two weeks, then stabilized over the remaining inundation period. The overall observed trends functionally represent the increased habitat value of controlled flooded post-harvest agriculture fields and demonstrate this management practice may provide a strong energetic contribution or "payoff" critical to wetland species at higher trophic levels.
A preliminary analysis of soil nutrients in agricultural and forest habitats in the Mississippi Delta
Year: Authors: Stevens E., Yasarer L.M. W., Taylor J., Locke M., Moore M.
As a historical floodplain of the Mississippi River, MS Delta soils are anticipated to have high natural nutrient content. In addition, years of farming and fertilizer applications have altered natural nutrient compositions and potentially created a legacy storage of soil phosphorus on agricultural land. This study is a step in a series of analyses and experiments to characterize and quantify legacy soil phosphorus in a variety of common soil types found in either agriculture or forest habitats throughout the Mississippi Delta. Soil and sediment samples were taken from 73 locations comparing agriculture and forest environments within four different soil types: Dundee, Forestdale, Alligator, and Sharkey. Samples were taken in triplicate to total 219 samples, which were each homogenized in the laboratory. The field-moist samples were processed immediately, while the dried samples were air-dried, ground, and sieved to less than 2mm. Both field-moist and dried samples were extracted in aerobic environments. Extractions were performed on field-moist samples to extract water soluble phosphorus. Samples were analyzed for carbon, nitrogen and sulfur on an elemental analyzer. Mehlich-3 extractants were analyzed for phosphorus, potassium, calcium, magnesium, sulfur, sodium, iron, manganese, zinc, copper, boron, and aluminum using inductive coupled plasma (ICP) mass spectrometry. This initial analysis will compare soil phosphorus content in managed-agricultural vs. "natural" forest habitats, evaluate the spatial distribution of nutrient content throughout the Delta, and evaluate correlations amongst measured nutrient and mineral components. This work sets the stage for a deeper analysis of phosphorus availability in different soil types and development of predictive relationships to estimate phosphorus in soils throughout the Delta.
Development of a Web-Based Agricultural Integrated Management System (AIMS) for Watershed Management: A case study for the Johnson Creek-Long Creek Watershed in Panola County, Mississippi
Year: Authors: Pophet N., Ozeren Y., Bingner R., Yasarer L., Smith P., Ramalingam V., Yafei J.
The National Center for Computational Hydroscience and Engineering (NCCHE) and the USDA-ARS-National Sedimentation Laboratory have developed a web-based Agricultural Integrated Management System (AIMS) to provide a powerful watershed conservation management planning tool in easy to use technology. This technology provides modeling capabilities with automated data preparation from seamless geospatial data for use in evaluating runoff, sediment, and agro-pollutant loadings for any watershed in the U.S. via a Web-browser. The ultimate goal of AIMS is to provide capabilities such as (i) viewing and interacting with geospatial layers, (ii) acquiring information describing features from geospatial layers for a user-defined area, (iii) launching modeling tools for topographic landscape analysis (TopAGNPS) and agricultural watershed simulations (AnnAGNPS), and (iv) accessing various Decision Support tools to allow users to compare various simulated conservation planning scenarios. The beta version of AIMS is currently available and can be accessed via the address "aims.ncche.olemiss.edu." In order to evaluate AIMS for adequate input data preparation required for AnnAGNPS watershed simulations, a case study was performed on the Johnson Creek-Long Creek HUC 12 Watershed (155.85 km<sup>2</sup>) located in northwest Mississippi. The input parameters required for use with the AnnAGNPS model includes soil, climate, land use, and crop data, which can be automatically prepared through AIMS. Soil information was prepared by AIMS from the USDA-NRCS Soil Survey Geographic (SSURGO) Database. The climate generator-GEM6 was used to generate climate data. Land use and crop data were obtained from the USGS 2016 National Land Cover Database (NLCD) and the USDA 2018 Crop Data Layer (CDL), respectively. The performance of the AIMS system to adequately describe this watershed was evaluated by comparing the observed runoff at an in-stream measuring station with the AIMS-AnnAGNPS simulated results.
Estimating the century-long precipitation trends in Lower Mississippi River Alluvial Valley using nonparametric analysis?
Year: Authors: Ouyang Y., Feng G., Moran M.
Climate change is a natural phenomenon, but anthropogenic activities such as fossil fuel burning, industrial pollution, deforestation, and population growth have greatly accelerated the greenhouse gaseous emissions and have resulted in abnormal climate change patterns. Climate change over the last several decades has been linked to atmospheric water vapor content increase, precipitation pattern shifts, snow cover reduction and ice melt, and surficial hydrological process cycle changes. Lower Mississippi River Alluvial Valley (LMRAV) is an economic artery of Mid-south USA, which is prone to natural disasters from extreme climate events and is well known for cyclic flooding events, groundwater level decline, and surface water quality degradation. Currently, our knowledge on long-term precipitation trends in this region is fragmented. Using the past 100 years measured daily precipitation data from six watersheds within the LMRAV in conjunction with nonparametric analyses (i.e., Kruskal-Wallis, Dunn, Mann-Kendall, and Pettitt tests), we found that there were significant increasing trends (p < 0.05) in annual precipitations near the coastal area. A spatial variation in seasonality was also observed at the decadal scale. Results from this study are useful to water resource managers for adapting the changing climate conditions in the LMRAV.
Effects of cover crops on edge-of-field water runoff in the mid-south
Year: Authors: Lucore A., Baker B., Aldridge C.
Efforts to reduce nutrient transport from agricultural landscapes has led to research and implementation of numerous conservation practices. Cover crops have been widely documented in certain regions of the country, primarily the Midwest, to provide water quality, soil health, and wildlife benefits to the environment, as well as to the agricultural system in the form of weed and pest suppression. A lesser body of research exists in the mid-south, particularly in respect to water quality where the bulk of the research refers to the benefits to soil and soil structure while the effects on water quality are ancillary. This study investigated the effects of cover crops on runoff in row-crop production systems. This study was conducted on a working farm located in Tippah County, Mississippi, where six plots (0.7–6.5 ha [1.8–16.1 ac]) served as treatments and controls. Four plots were randomly selected and planted with cover crops and the remaining two plots served as controls, all plots had been under no-till for 20+ years. Water quality was monitored via automated storm-based sampling at all locations for two years prior to cover crop implementation at the treatment sites (2014-2015) and for four years post cover crop implementation (2016-2019). Water samples were analyzed for nitrate-nitrite, total nitrogen, orthophosphorous, total phosphorous, and total suspended solids within 48 hours of sample collection. Data analysis indicated reductions among all analytes besides orthophosphorous with nitrate-nitrite concentrations being the most pronounced reduction. Additionally, there was considerable variability amongst season, cover crop type, and cash crop species.
Integrating high-resolution remote sensing data for improved agricultural soil water monitoring
Year: Authors: Lei F., Moorhead R., Crow W.T., Kurum M.
Improving water usage efficiency is of critical importance for sustainable agriculture water management. Over the past few decades, extensive field investigations and numerical modeling have been conducted to quantify surface water and energy fluxes at different spatiotemporal scales. Meanwhile, with the development of satellite-based sensors, high-resolution land surface hydrological variables can be retrieved remotely to supplement ground-based observations. However, both models and remote sensing retrievals are subject to various sources of errors. An accurate and spatiotemporally continuous soil water monitoring at the subfield-scale is crucial for efficient agriculture water management. Particularly, data assimilation techniques can optimally integrate measurements acquired from various sources (including in-situ and remotely sensed data) with numerical models by considering different uncertainties. In this presentation, we present some recent work on monitoring soil water content over a vineyard in California. Specifically, high-resolution evapotranspiration estimates derived from satellite-based thermal imagery and surface soil moisture retrievals from synthetic aperture radar sensor are optimally incorporated into a Water-Energy-Balance Soil Vegetation Atmosphere Transfer (WEB-SVAT) model via data assimilation methods. Results demonstrate that the simulation of soil water content in the SVAT model can be enhanced through the assimilation of high-resolution remote sensing data with reduced errors compared to independent ground-based measurements. This work can foster improved irrigation strategies with the availability of continuous and accurate soil water monitoring at subfield-scale for agriculture.
Methods for assessing the impact of soil amendments and cover crops on soil health
Year: Authors: Chang T., Paul V., Feng G.
Soil health assessment tools can help evaluate whether agricultural measures contribute to sustainable development. The indicators used to evaluate soil health are generally composed of soil physical (including hydrological), chemical, and biological properties. However, quantifying and integrating soil health indicators is a complex and time-consuming process. Currently, there are several methods available for assessing soil health, such as standard scoring functions (SSF) method, Cornell soil health assessment (CSHA) tool, Ontario soil health assessment method (OSHA), and soil management assessment framework (SMAF). However, some of these assessment tools have been shown to be inconsistent due to high variability in soil and climatic characteristics and the sensitivity of soil health indicators caused by different agronomic management methods. Therefore, the applicability of soil assessment methods should be evaluated locally, and include weighted calculations based on soil characteristics. This study selected three methods, SSF, CSHA, and OSHA, and included two methods of weight vector calculation: analytic hierarchy process and iterative algorithm. In total, six methods were employed to calculate the soil health scores. Soil data were obtained from a 7-year experiment conducted in the state of Mississippi, which consisted of four fertilization systems (unfertilized control, commercial inorganic N fertilizer, and pelletized poultry litter with/without flue gas desulfurization (FGD) gypsum) and two cover crop treatments (wheat winter cover crop and fallow). The objectives of this study are: 1) to quantify selected soil physical, chemical, and microbiological indicators in the upper 0-15 cm of soil; 2) to compare soil physical, chemical, and biological attributes between contrasting, innovative management practices; and 3) to assess the sensitivity of different soil health scoring methods. Preliminary analysis of soil physical, chemical, and microbial indicators in the study area showed that wheat winter cover crop and pelletized poultry litter, especially in combination with gypsum, can significantly increase soil health scores. The results are expected to determine which soil health assessment tools are more sensitive and help in showing numerical differences in soil health scores among different fertilization regimes and cover crops in the state.
Estimating streambed hydraulic conductivity for selected streams in the Mississippi Alluvial Plain using continuous resistivity profiling methods
Year: Authors: Adams R., Miller B., Kress W.H., Minsley B., Rigby J.R.
The U.S. Geological Survey (USGS) is currently conducting a multi-year analysis and recharacterization of the Mississippi Embayment Regional Aquifer System (MERAS) groundwater flow model focusing on the water resources within the Mississippi Alluvial Plain (MAP). Part of this recharacterization was the evaluation of the existing model based on uncertainty and data worth analysis. These data quality measurements indicated that the MERAS model was sensitive to groundwater-surface water exchange, but this component was poorly constrained and the confidence in the model forecast was low.<br /><br /> To increase the density of data within the models' most sensitive rivers and streams, the USGS completed 900 kilometers (km) of waterborne resistivity surveys within Mississippi to characterize streambed lithology. This technique characterizes streambed itself and the near surface (upper 15-30 meters) of the streambed that controls the recharge to the alluvial aquifer. These data can be used to map changes in the lithology of the streambed and identify areas of potential groundwater-surface water exchange. <br /><br /> To map these sediments, electrical resistivity data was collected using a resistivity meter connected to floating multi-electrode cables. Information about the spatial location of each data point, depth of the water column, and electrical properties of the water column were also collected. <br /><br /> Five rivers in the Mississippi Delta region were the focus of this study: the Bogue Phalia, Quiver, Sunflower, Tallahatchie, and Yazoo Rivers. These rivers flow over a variety of fluvial and deltaic deposits. While streambed sediments show a strong correlation with surficial geology, changes in the vertical extent of those geologic features had a strong impact on the aquifer recharge potential expected for a given water body. <br /><br /> The inverted waterborne resistivity data were transformed to hydraulic conductivity using relationships derived from geophysical logs collected within the study area. Estimated hydraulic conductivity values generated from downhole nuclear magnetic resonance (NMR) data were compared to electromagnetic induction logs to generate a relationship between electrical resistivity and hydraulic conductivity.<br /><br /> The resistivity-derived estimates of hydraulic conductivity show a significant increase in magnitude and spatial variability as compared to the estimates derived from groundwater model parameter estimation. Some amount of this change was expected due to the increased sampling density and smaller footprint of the resistivity surveys. The remainder of the difference between the two estimates is likely due to the incision of river channels into and beneath the shallow 5-10 m confining unit that overlays a large portion of the MAP within Mississippi.
Impact of long-term organic fertilizer on soil physical health of high tunnels in the Southern United States
Year: Authors: Zhang Y., Feng G., Bi G., Yu S.
Soil health in agricultural production represents soil quality and productivity. Soil bulk density (BD), aggregates, particle size, porosity, saturated hydraulic conductivity, and field-saturated hydraulic conductivity (measured with the Guelph permeameter method) are important indicators of soil physical health. Previous studies show that compost and organic fertilizer can improve soil physical properties and reduce soil BD under high tunnels and outdoor conditions. However, a 3-year open-field study shows that different composts have different effects on soil physical properties (BD, aggregate stability, and saturated hydraulic conductivity). In addition, most studies are conducted in the open-field, or in pots and plots of the high tunnels. The environment between high tunnels and open field are quite different, which related to irrigation, fertilization, and weather conditions. The objectives of this study were: 1) using open-field soil as a control to determine whether the application of organic fertilizer affects soil BD, aggregate stability, particle size, porosity, total porosity and permeability in the high tunnels; and 2) to compare changes in soil physical health with the application years of organic fertilizer. The study quantified the effects of different application years of organic fertilizer on soil bulk density, aggregate stability, and permeability, which can provide fundamental guidance for growers to formulate fertilization systems to improve soil physical properties in the Southern United States.
Rice yield and groundwater level as affected by irrigation management in Mississippi Delta
Year: Authors: Wang M., Feng G., Li Y., Wang Y.
Traditional irrigation of rice, consume as high as 3.0 feet/acre, seriously threatens the sustainability of rice production and attributes to declining of groundwater level in the Big Sunflower River Watershed (BSRW). Non-traditional irrigation management, conjunctive use of surface water (in streams and ponds) and groundwater, potentially ensure the rice yield and the sustainable availability of groundwater. Nevertheless, the potential impact of non-traditional irrigation on rice yield and groundwater level were rarely reported. In this study, the Soil and Water Assessment Tool (SWAT model) was calibrated using 15 years (2000-2015) field data and was validated by 3 years (2015-2018) field data, then applied to simulate the future change trends of rice yield and groundwater level under conventional and non-conventional irrigation scheme, among which the non-traditional irrigation presented different ratios of surface water and groundwater for irrigation (setting up six scenarios: 0% (in entire planting season), 40% (in May), 20% (in June), 30% (in July), and 100% (in August) reductions in weekly pumping replaced by surface water, and a combination of the last four replacement). The results showed that traditional irrigation (0% replacement in entire planting season) would decrease groundwater level by 140-300 mm yr-1 and make rice yield drop by 5%-20% during 2019 to 2030. Compared with traditional irrigation, the combination of 40% (in May), 20% (in June), 30% (in July), and 100% (in August) reductions in weekly pumping replaced by surface water would more effectively mitigate the significant decrease of groundwater level and rice yield than the replacement in a given month. Additionally, rainfall in planting season was taken account into the demand of rice irrigation, since the results implied that the storage capacity of ponds has a distinct impact on the groundwater level. Overall, this study suggested that the non-traditional irrigation of combing surface water and groundwater could be a more sustainable way for future to continuously grow rice than the traditional irrigation of single groundwater resource in the Mississippi Delta.
Soil water characteristic in relation to textural composition and organic matter content under biochar application
Year: Authors: Li Y., Feng G., Tewolde H.
Estimating soil water hydraulic characteristics from readily available physical parameters has been a long term goal of soil physicists and engineers. Several equations were developed according to the relationships between soil water characteristics, soil texture and soil organic matter and commonly applied to hydrologic analyses. Especially the hydrological equations of Saxton et al. (2006) performed the best. BC, as is a valuable soil amendment, has been reported to have a positive effect on the soil health. Thus it may affect on soil water characteristics because of its inherent properties such as high pH, high cation exchange capacities (CEC), high specific surface area and soil organic matter. Thus, a hydrological equation for biochar addition to soil should be found or calibarated and then was compared to the hydrological equations of Saxton et al. (2006) to evaluate soil water infiltration, conductivity, storage, and plant-water after biochar addition. In this study, we collect 180 soil samples in four farmer fields applied biochar at 6.73 Mg/ha every year by spreading way on soil surface for almost 5-10 years. We will measure and get soil water characteristics curve; bulk densities; sand (S), silt and clay (C) particle sizes and organic matter of 0-5 cm (A), 5-10 cm (B) and 10-15 cm (C) layers. Then the regression equations were developed and the comparison between the new hydrological equations and hydrological equations of Saxton et al. (2006) will be analyzed. The experiment and result are still in progress.
Impact of conventional and water-saving irrigation schemes on soybean yield in Big Sunflower River Watershed
Year: Authors: Heng T., Feng G., He X., Li F.
Big Sunflower River Watershed (BSRW) is a high-yield agricultural area in the Lower Mississippi river. More than 81% of the total area of the BSRW (approximately 10,488 km2) is agricultural land. Crop yields are often limited by extreme climate events and soil field capacity. Due to these factors, the yield of crops in different regions of BSRW is quite different. For example, in 2013, the soybean yield of Humphreys County, Mississippi was 10.12 bu/acre lower than that of Washington county. Reduction in yield and improving the sustainability of farmland ecosystem is continuous improvement of water use efficiency. However, the model of soybean yield in BSRW has not been calibrated and the effects of different irrigation schemes on soybean yield are rarely reported. In this study, the soil water assessment tool (SWAT model) was calibrated using 20 years (1998-2018) BSRW soybean yield data, then the soybean yield was employed to simulate under non-conventional irrigation schemes. The non-conventional irrigation schemes are the ET-based irrigation method. the amounts of irrigation were set to 50%, 60%, 70%, 80%, 90%, and 100% of crop evapotranspiration (ET). That is, When the soil water storage in 50 cm is lower than the design value of replacement percentage of ET, irrigation was triggered until the irrigation amount reached the ET percentage. The results indicated that soybean yield was positively correlated with ET (R2=0.83). The yield of soybean was 79.23 bu/acre under 80% ET, it was 3.27 bu/acre higher than conventional irrigation. For every 10% increase of ET (50~80%), the average increase of soybean yield is 5.41 bu/acre. Thus this study suggests that the ET irrigation scheduling method can close the gap of soybean yield, so as to make more effective use of irrigation water.
The Influence of Agricultural Water Management Practices on Groundwater Budget in Big Sunflower Watershed
Year: Authors: Han Y., Feng G., Ouyang Y., Jin W., Liu Z., Jenkins J.
The groundwater was heavily used for irrigating crops in Big Sunflower River Watershed (BSRW). Traditionally, many farmers chose to flood irrigation, which wasted large amount of groundwater and resulted in severe groundwater table declining. This study applied a coupled SWAT-MODFLOW model to investigate the influence of different agricultural water management practices on groundwater budget. The agricultural water management practices are composed of (1) pumping groundwater for irrigation based on farmers' conventional irrigation schedule. (2) Drafting groundwater for irrigation in terms of plant water demand (3) No irrigation on farmland. Comparing groundwater recharge, groundwater irrigation amount, groundwater return flow and groundwater ET to obtain the difference of groundwater budget in three agricultural water management practices. Cell-wise water table elevation for three agricultural water management practices will indicate the groundwater table spatial distribution characteristics. Results can assist with groundwater management.
Efficiency Analysis of Green Stormwater Infrastructure Practices for Runoff Reduction
Year: Authors: Abera L.E., Surbeck C.Q.
Increased impervious land surfaces due to urbanization, construction, and development cause excess stormwater runoff and result in urban areas experiencing flooding events and erosion. Installation of Green Stormwater Infrastructure (GSI) is one sustainable way of reducing flooding events and preventing damage. In this study, computer simulations were conducted to assess the efficiency of GSI practices in flood reduction. Life-cycle cost analyses (LCCA) of stormwater infrastructure are also being performed to determine the cost-effectiveness of GSI practices, considering capital and operation and maintenance (O&M) costs, which are costs borne by different stakeholders. A proposed development located in Oxford, MS was used as a model site to perform the assessments. The HydroCAD stormwater modeling tool was used to perform hydrologic modeling for two types of GSI practices, permeable pavement and rain garden. The site was modeled using the curve number reduction method, which reduces the weighted average curve number of the site by implementing GSI practices. For multiple scenarios, the volume of stormwater runoff was estimated based on the city's design storms. Depending on the type and size of the GSI and the storm intensity, the simulation results showed that applying GSI reduced the volume of excess runoff by 3 to 17% on average, therefore potentially reducing the volume requirement for underground storage. For the constraints at the modeled site, compared to a rain garden, pervious pavement resulted in a higher reduction in the volume of stormwater runoff. Life-cycle cost analysis was performed using the Water Environment Research Foundation (WERF) Low Impact Development Cost Analysis Tools. Results of the cost analysis, and what it means for stakeholders, will be presented.
Long-term soil physical responses from integrating cover crops and no-till management to agricultural soils in the Mississippi Alluvial Valley
Year: Authors: Firth A., Baker B., Brooks J., Morin D., Brown A., Locke M.
Agriculture is the greatest contributor to overall consumptive water use with deleterious effects seen in river depletion and groundwater over draft. Despite negative documented effects of agricultural land use (i.e. soil erosion, compaction, nutrient runoff) on critical natural resources (i.e. water), food production must increase in order to meet the demands of a rising human population. Given the environmental and agricultural productivity concerns of intensely managed soils, there is a growing interest in conservation practices that mitigate the negative effects of crop production and enhance environmental integrity. This study assed the long-term soil physical responses from integrating cover crop (CC) and no-till (NT) management to agricultural soils in the Mississippi Alluvial Valley region of Mississippi, USA. Bulk density, aggregate stability, water holding capacity and water infiltration were measured after 5 years of CC and NT treatments. It was hypothesized that the combination of a diverse CC mixture and NT management would provide more favorable soil physical properties compared with single CC mixtures or tillage treatments. Results of this study are expected to provide valuable information to producers in the mid-south region of the cost and benefits of CC/NT usage.
Assessing nutrient mitigation potential of short rotation woody crops in marginal croplands of the Lower Mississippi Alluvial Valley
Year: Authors: Kyaw T.Y., Siegert C., Renninger H.
Agricultural runoff loaded with surplus nutrients contributes to degradation of water quality of the Lower Mississippi Alluvial Valley (LMAV). In the LMAV, marginal lands experiencing frequent floods and seasonally high water tables may be less suitable for conventional agriculture. In such riparian areas, planting short rotation woody crops (SRWCs) as feed stocks for bioenergy production and also as vegetation filter strips can meet complementary goals of income generation and nutrient mitigation. Considered as the nutrient concentration hotspot, the Mississippi Delta of the LMAV is both geographically and ecologically important for minimizing nutrient delivery to the Gulf of Mexico. Therefore, this study aims to quantify composition of nutrients (e.g., dissolved organic carbon, total phosphorus, ortho-phosphate, and inorganic nitrogen) in groundwater of a SRWC plantation and access survival during an exceptional flood year. In June 2018, 300 cottonwood (<em>Populus deltoides</em>) and 300 willow (<em>Salix nigra</em>) cuttings, and in November 2019, 300 sycamore (<em>Platanus occidentalis</em>) seedlings were planted in Sidon, MS adjacent to an oxbow of the Yazoo River. Groundwater samples were collected from 16 groundwater wells with a depth of approximately 2 m at the highest, lowest and midpoints in each of four replicated plantation blocks. Additionally, water level loggers were placed inside the groundwater wells to monitor water level changes. During the late growing season when water tends to be limiting in the region, groundwater levels were within 1 m of the surface in 2018 and 0.8 m in 2019, whereas the site was continuously flooded in the dormant season up to 1.2 m in 2018 and 3.9 m in 2019. Because of such exceptionally high flooding, survival of willows decreased from 98% in 2018 to 35% in 2019, and cottonwoods decreased from 62% in 2018 to 15% in 2019. Among the four replicates, no survival was found in the two blocks that were continuously underwater from January to August and had deeper floodwater (3.8 m) above them. Only the trees which had continuous but shorter floods (January to June) and less deep water (3.6 m in willows and 3 m in cottonwoods) survived. Besides flooding, beavers damaged 30% of the surviving willows, whereas no damage was found in cottonwoods. Analyses of water quality data are pending. Therefore, even though there were extreme floods in 2019, SRWCs could tolerate a continuous six-month flooding with a height of up to 3.6 m for willows and 3 m for cottonwoods.
The performance of a model floating breakwater for embankment protection
Year: Authors: Rossell W., Ozeren Y., Wren D.
Wave erosion is a costly problem for many farmers that own irrigation reservoirs located in the Mississippi River Valley Alluvial Floodplain (Delta). Breakwaters are commonly used for shoreline protection in coastal areas. Fixed breakwaters, such as rubble mounds, are expensive to construct and maintain. A relatively cost-effective method for embankment protection is the use of a floating breakwater. This study utilized a 1:3 scale, model cylindrical floating breakwater that was subjected to waves of varying height, period, and still water depth in a laboratory wave tank. The results of this study will be used to design a prototype scale floating breakwater at a pilot reservoir in the Delta. The experiments were carried out at the USDA-ARS, National Sedimentation Laboratory in Oxford, MS. The model breakwater was made of a 69 cm long High Density polyethylene (HDPE) corrugated pipe section, filled with water and moored using steel wires attached to the floor of the flume. The resulting draft was approximately 90% of the outer diameter. The model was subjected to regular waves generated by a piston type wavemaker. Waves were measured using capacitance type wave staffs located both upwave and downwave of the breakwater. The resulting forces in the mooring cables were measured using a force gauge. This paper presents some of the key observations during these laboratory experiments.
Effects of Sensor Threshold Irrigation Scheduling on a Soybean-Cover Crop
Year: Authors: Russell D., Singh G., Kaur G.
The Mississippi River Valley Alluvial Aquifer (MRVAA) is the main source for irrigation water supply for soybean production in the Mississippi Delta. However, MRVAA is depleting at a rate faster than it can be recharged. Decline in ground water levels in MRVAA necessitates the use of better agronomic practices and irrigation management for saving water and increasing water use efficiency. Research has been done in the past using various irrigation scheduling techniques on monoculture soybeans, but there is limited information available on irrigation scheduling of soybean with combination of winter cover crops. The goal of this study is to evaluate the effects of sensor thresholds for irrigation scheduling on soybean production, with and without cover crops on a sandy loam soil. This study also determines the effects of irrigation scheduling and cover crops on economic returns, soil available nutrients , irrigation water use, and water use efficiency. The field experiment was initiated in fall 2019 at the Delta Research and Extension Center in Stoneville, MS. The four cover crop treatments included in this study were: cereal rye, hairy vetch, a wheat-radish-turnip mix, and a no cover crop control. The three irrigation treatments used for irrigation scheduling were: a season-long single threshold (-85kPa), a dual threshold (-50 kpa at Tamax>=95°F and -85 kPa at Tamax<95°F), and a non-irrigated control. The baseline data was collected in fall 2019 including soil infiltration rates, bulk density, and penetration resistance. Soil samples were also collected in fall 2019 for soil health analysis. The results from this study will be presented at the conference.
Runoff Water Quality and Quantity in Conservation Management Systems under Simulated Rainfall
Year: Authors: Spencer D., Krutz J., Gholson D., Locke M., Henry B., Golden B.
Midsouthern USA silt loam soils are characterized by poor soil structure, which contributes to decreased rainfall capture and increased susceptibility to erosion and off-site nutrient transport. Conservation management practices such as cover crops and no-tillage may improve infiltration and decrease contaminant runoff, thus promoting the sustainability of regional waterbodies. The effects of cover crops and tillage system on runoff water quantity and quality under simulated rainfall were evaluated on a Commerce very fine sandy loam (fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquepts) at Stoneville, MS from 2017 to 2019. Neither cover crops nor no-tillage decreased runoff under simulated rainfall. In 2017 and 2018, cover crops did not have an effect on water quality. No-tillage improved turbidity, but also increased runoff water concentrations and loads of some nutrients. Water quality results from 2019 will be presented as well.
Numerical Modeling of Flow and Salinity in Lake Pontchartrain and Mississippi Sound during the Bonnet Carré Spilling Flood Release
Year: Authors: Chao X., Zhang Y., Jia Y.
The Bonnet Carré Spillway (BCS) of the Mississippi River was constructed from 1929 to 1936 for flood control. In order to protect the city of New Orleans, when the water stage of the Mississippi River approaches 5.18 meters, BCS will be opened to divert the excessive flood water into Lake Pontchartrain and the Gulf of Mexico. The distributions of salinity, sediment, nutrients, and aquatic habitat, in Lake Pontchartrain as well as the Northern Gulf of Mexico, especially the Mississippi Sound are strongly affected by these flood releasing events. <br /><br/ > This research is about the application of a two-dimensional numerical model (CCHE2D) developed at the National Center for Computational Hydroscience and Engineering, University of Mississippi, on simulating the dynamic flooding process and associated temporal and spatial distributions of salinity in the Lake Pontchartrain and Mississippi Sound during these flood release events. The simulated results are compared with field measured data provided by USGS and Army Crop of Engineers, and good agreements were obtained. The flow patterns and salinities distribution processes in the lake and Mississippi Sound due to the BCS flood release events are discussed. In addition, the salinity recovery processes in the water were also simulated. The simulation results provides useful information to analyze the environmental impacts of the BCS opening flood events on aquatic ecosystems.
Microplastics in the Mississippi River System and at Oyster Reefs along the Mississippi Coast: An Update
Year: Authors: Cizdziel J., Scircle A.
Microplastic (MP) concentrations along the northern Gulf of Mexico are among the highest levels reported globally. The most likely source of the plastic pollution is the Mississippi River (MR) which drains much of the central portion of the USA. Yet, surprisingly little is known about the concentrations, types, sizes, and loadings of MPs in the MR and its major tributaries. This lack of data is hindering our understanding of the magnitude and sources of the problem. Because the MR is an intricate system of waterways, tributaries, and commercial routes, an in-depth spatial study is needed to fully assess MP pollution in the system. Our research aims to systematically quantify the concentrations and loads of MPs in the MR system and at oyster reefs along the Mississippi Coast, and characterize their shapes, size distribution, and chemical composition. To that end, we developed and validated a one-pot method for the collection and preparation of water samples for microplastic analyses. The method prepares samples in the same vessel (Mason jars) that they are collected in right up until the MPs are transferred onto filters or spectroscopic windows for analyses. The method minimized contamination, degradation, and losses, while increasing recoveries and throughput when compared to conventional sieving. We applied it to surface grab samples collected from the Mississippi River and its major tributaries during and after historic flooding in 2019. Microplastics (>~30 µm) were detected by fluorescence microscopy and identified by Imaging Fourier Transform Infrared micro-spectroscopy (µFTIR-Imaging). Concentrations were lower during the flooding, likely due to dilution. Mean concentrations (counts/L) ranged from 14 in the Tennessee River during flooding to 83 in the Ohio River during low-flow (summer) conditions. Loads of MPs tended to increase down river and ranged from ~87 to ~129 trillion MPs/day near New Orleans. Most of the MPs (>60%) were in the lower size fraction (30-90 µm), consisted primarily of fragments (~85%), followed by fibers (~8%) and beads (~7%), with polyethylene, polyester, and polyacrylate as the primary MP type. Analyses of samples collected near Mississippi oyster reefs are underway and results will be presented at the meeting.
A Study Case to Evaluate the Performance of the Agricultural Policy/Environmental Extender Model (APEX) in the Mississippi Delta Region
Year: Authors: Mendez-Monroy J.F., Ramirez-Avila J.J.
The use of computer programs to understand the dynamics and interactions of soil, hydrologic and crop production processes, have allowed scientists, researchers and farmers to facilitate and improve decision-making procedures. The Agricultural Policy/Environmental Extender Model (APEX) is a tool capable of performing long term simulations (1-4000 years) on a daily time step, for the managing of whole farms or small watersheds. APEX allows users developing analyses related to water balance, nutrient balance, and sediment transport. To highlight the potential of APEX in predicting soil, hydrologic and crop production processes of agricultural scenarios in the Mississippi Delta, a study was developed for two fields with soybean and cotton under reduced tillage and winter cover crop practices. Available information about runoff, sediment transport, soils, operation schedules and crop yield for a period of four years was used for the simulation. A sensitivity analysis (SA) and a calibration (CA) and validation (VA) process were carried out using the APEX Auto-Calibration and Uncertainty Estimator tool (APEX-CUTE) to compare observed and simulated runoff depths from the study fields. Four parameters associated to the prediction of soil evaporation (PARM17), runoff (PARM20 and PARM42), and potential evapotranspiration (PARM 34) were recognized as sensitive. To perform the CA-VA process, APEX-CUTE uses an objective function designed to maximize the model performance efficiency (NSE) and reduce the tendency of the simulated values to be larger or smaller than their observed values (PBIAS). The objective function was evaluated 1000 times resulting in optimized values of NSE>0.70 and PBIAS≌0.070, and NSE>0.90 and PBIAS≌0.449 for CA and VA, respectively. The best parameter set was used to simulate runoff that was compared with observed data. In general terms, APEX was successful in predicting daily runoff. For the monthly and annual runoff, some variations were noticed (under and overestimations). Despite this, the model had an optimal performance, and in future studies, it could potentially be used as an assistant tool for agricultural, research and engineering purposes.
Assessment of wave energy reduction by marsh terraces utilizing a wave model
Year: Authors: Osorio R.J., Linhoss A., Sharke A., French J., Brasher M.
Wetland losses in the northern Gulf of Mexico are mainly due to subsidence, sea-level rise, and land erosion caused by wind driven waves. Marsh terracing is a relatively new coastal restoration technique implemented in Texas and Louisiana. Marsh terraces are segmented berms of soil that are built in inland, shallow coastal ponds. Marsh terraces are designed to create new marsh, reduce fetch and dissipate wind originated waves. Therefore, this restoration technique is hypothesized to slow down marsh platform erosion and pond expansion by reducing wave energy. Marsh terraces have been implemented for almost 30 years; however little research has been conducted to determine their effectiveness. The objective of this study was to assess which terrace design (rectangular or chevron) is most effective at reducing wind driven wave energy. This analysis was conducted using the Simulating Waves Nearshore (SWAN) model. The model simulated wind waves at two terrace fields in coastal Louisiana. Simulations were based on real terrace field conditions with and without terraces. Model input parameters included bathymetry, water level, as well as wind and wave characteristics. Model validation was done using in-field measurements collected for 5 months at each study field by an acoustic anemometer (wind time series), four doppler profilers, and a wave buoy (wave data). Results help us to understand the dynamics of wave energy related to the erosive forces exerted in two different marsh terrace designs under different field environments and weather conditions. At the end of this project we expect to identify the most effective terrace design for reducing wave energy which is related to marsh erosion, leading to marsh creation within these wetlands.
Artificial neural networks for filling data gaps and improving hydrologic simulations in coastal watersheds
Year: Authors: Upadhyay P., Linhoss A.
The accuracy of streamflow measurements and models is very important in water-resources planning and management. Traditionally, streamflow is simulated using physically based hydrologic models such as the Soil and Water Assessment Tool (SWAT). Previous studies have also compared SWAT with Arti?cial Neural Network (ANN) models to understand which give the best results. Traditional hydrologic models have the advantage that they simulate mechanistic processes which enables users to understand and quantify physical components of the system. In some cases, physical processes of a system are either unknown or unimportant. Here ANN models have the advantage that they can predict the relationship between the inputs and outputs of a process without an understanding of the physical characteristics of the system. We propose to combine the SWAT model with an ANN model to improve stream?ow estimation. We employ each of these models according to their strengths. The ANN model was used to fill gaps in time series data and estimate unknown physical processes. The data developed by the ANN model was used as an input into the SWAT model to simulate streamflow. The models were developed for a coastal watershed in Florida, which drains to the Biscayne Bay. Biscayne Bay has been recently designated as one of ten habitat focus areas across the country by the National Oceanic and Atmospheric Administration (NOAA). The Biscayne Bay region is unique because of its karst geology, flat topography, system of regulated surface canals, and the oligotrophic nature of the Bay. In the future, the developed model will also be used to simulate water quality in Biscayne Bay, Florida.
Strategic conservation assessment tool suite: a science-based conservation framework for the Us Gulf of Mexico region
Year: Authors: Samiappan S., Shamaskin A., Evans K., Liu J.
The overwhelming consensus among the conservation experts is the immediate requirement for efficient science-based geospatial conservation tools that can help guide or optimize the dollars spent on conservation based on the ecological benefits. In this work, we demonstrate a suite of conservation tools for conservation prioritization and visualization that enables integration of 1) openly available peer-reviewed data from federal and state agencies, 2) the priorities and values identified in local and regional plans with those identified by stakeholders representing local and regional agencies and organizations, and 3) a multi-criteria decision analysis (MCDA) based optimization framework for assessing potential conservation projects. The framework developed as part of this work is implemented as geospatial web tools. The tool was developed and tested with five conservation goals proposed by the Gulf of Mexico (GoM) Restore Council and was used as a framework for grouping the identified conservation plans and projects. The goals are 1. Restore and Conserve Habitat, 2 Restore Water Quality, 3. Replenish and Protect Living and Marine Resources, Enhance Community Resilience, and Restore and Revitalize the Gulf Economy. The tool suite consists of three tools, 1) conservation inventory tool (CIT), 2) conservation prioritization tool (CPT) and 3) conservation visualization (CVT). The CIT is the first large-scale regional assessment of conservation planning efforts across governmental and non-governmental organizations encompassing all ecosystem types in the GoM. This comprehensive inventory tool is vital to understand the key factors that may drive existing conservation efforts, as well as identify potential gaps in conservation planning efforts. The CPT is using existing data with the MCDA to provide decision support to search for the project or ranking of all the alternatives based on decision-makers' preferences. Decision-makers prefer a decision support method that doesn't require explicit preference information from them due to several political and apolitical reasons. The CPT can provide decision support merely on potential land parcels and publicly available peer-reviewed or government-provided data can alleviate any bias and thereby provide purely science-based support. The CVT is developed to enable the users to explore the data behind CPT to identify potential regions using MCDA for conservation in the GoM. The CVT does not require potential project footprints to perform CPT like analysis rather it is performed on small hexagon parcels of 1 square km size spread across GoM.
The Efficiency of High-Resolution Wave Dataset on the Performance of Wave Modeling
Year: Authors: Baghbani R., Linhoss A.
Coastal wind-driven waves play an important role in transportation and exchange of mass and energy. The amount and intensity of wave energy determines the rate of erosion and deposition in estuarine systems. Having a continuous spatial-temporal understanding of wave energy can provide a better understanding of coastal processes. Models are convenient tools for wave studies because of their temporal and spatial coverage and resolution.<br /><br /> The aim of this study was to develop and validate a wave model for the Back Bay Biloxi, Mississippi in the northern Gulf of Mexico. The SWAN software (Simulating Waves Nearshore; Delft University of Technology) coupled with ADCIRC (Advance Circulation) was used to simulate wave height and direction. SWAN input data includes: wind speed, wind direction, and a bathymetric mesh. Due to the complexity of the area, an unstructured bathymetric mesh was generated using SMS software (Surface-water Modeling System; US Army Corps of Engineers).<br /><br /> One limitation in many wave modeling studies is the lack of spatially robust wave measurements that can be used for validation. This is due to the fact that installing a large number of wave gauges, in any one site, is usually cost prohibitive. In this study we deployed 38 relatively cheap DIY wave gauges to comprehensively measure wave conditions in Back Biloxi Bay. Wave gauges were deployed three times between June and August 2019 for 7 days during each deployment. These data were used to validate the wave model. Consequently, this study provides a novel validation of a wave model by way of a spatially comprehensive wave measurement dataset.
Occurrence of microplastic pollution at oyster reefs and other coastal sites in the Mississippi Sound, USA: Impacts of freshwater inflows from flooding
Year: Authors: Scircle A., Cizdziel J.V., Tisinger L., Anumol T., Robey D.
Much of the seafood that humans consume comes from estuaries and coastal areas where microplastics (MPs) accumulate, due in part to continual input and degradation of plastic litter from rivers and runoff. As filter feeders, oysters (Crassostrea virginica) are especially vulnerable to MP pollution. In this study, we assessed MP pollution in water at oyster reefs along the Mississippi Gulf Coast when: (1) historic flooding of the Mississippi River caused the Bonnet Carré Spillway to remain open for a record period of time causing major freshwater intrusion to the area and deleterious impacts on the species and (2) the spillway was closed, and normal salinity conditions resumed. Microplastics (~25 μm-5 mm) were isolated using a single-pot method, preparing samples in the same vessel (Mason jars) used for their collection right up until the MPs were transferred onto filters for analyses. The MPs were quantified using Nile Red fluorescence detection and identified using laser direct infrared (LDIR) analysis. Concentrations ranged from ~12 to 381 particles/L and tended to decrease at sites impacted by major freshwater intrusion. With the spillway open, average MP concentrations were positively correlated with salinity (r = 0.87, p = 0.05) for sites with three or more samples examined. However, the dilution effect on MP abundances was temporary, and oyster yields suffered from the extended periods of lower salinity. There were no significant changes in the relative distribution of MPs during freshwater intrusions; most of the MPs (>50%) were in the lower size fraction (~25-90 μm) and consisted mostly of fragments (~84%), followed by fibers (~11%) and beads (~5%). The most prevalent plastic was polyester, followed by acrylates/polyurethanes, polyamide, polypropylene, polyethylene, and polyacetal. Overall, this work provides much-needed empirical data on the abundances, morphologies, and types of MPs that oysters are exposed to in the Mississippi Sound, although how much of these MPs are ingested and their impacts on the organisms deserves further scrutiny. This paper is believed to be the first major application of LDIR to the analysis of MPs in natural waters. <a href="https://doi.org/10.3390/toxics8020035" target="_blank" aria-label="Download https://doi.org/10.3390/toxics8020035">Download full article</a>
The Summer of 2019: Overview of Harmful Algal Bloom that affected Mississippi's Beaches
Year: Authors: Beiser M., Cotton E.
The Mississippi Department of Environmental Quality (MDEQ) through its Beach Monitoring Program documented an algal bloom with the potential to become harmful on June 21, 2019. Salinities in the western Mississippi Sound had dropped to low levels---< 3 ppt beginning in March 2019 due to recent heavy rains, and the opening of the Bonnet Carré Spillway for an unprecedented second time in 2019. A <em>Dolichospermum</em> bloom was discovered offshore in mid-June by the Mississippi Department of Marine Resources (MDMR) which notified MDEQ as this bloom moved nearshore, and it was confirmed microscopically in the nearshore environment where it would come into contact with bathers on June 21, 2019 in Hancock County, in western MS. This resulted in a "Water Contact Warning" being issued the next day for Hancock County beaches. By June 24, 2019 both <em>Microcystis</em> and <em>Dolichospermum</em> were detected in Beach Monitoring Program samples. Within 2-3 days, the bloom consisted only of <em>Microcystis</em>. By July 7, a water contact warning had been issued for all MS beaches. <br /><br /> Tropical Storm Barry came ashore on July 13, 2019, dumping large amounts of freshwater over the area. By July 18, another <em>Dolichospermum</em> bloom was noted in Hancock County. Again, the <em>Dolichospermum</em> bloom persisted for only 2-3 days after which the bloom was exclusively <em>Microcystis</em>. Beaches were reopened on October 4, 2019 after little to no presence of <em>Microcystis</em> in water samples, and analytical results came back well below the EPA recommended Microcystin levels of 8µg/L.
Biogeochemical Impacts of Altered Freshwater Flow to the Mississippi Sound
Year: Authors: Dillon K.S., Milroy S.P., Shiller A.M.
The Bonnet Carré Spillway (BCS) is a flood control structure on the lower Mississippi River that is periodically opened at peak flow to prevent flooding in New Orleans and other municipalities. Since its construction in 1931, the spillway has only been opened fourteen times. However, in recent years, spillway openings have become more common with four openings since 2016. In 2019, the BCS was opened twice for a combined total of 123 days, sending large amounts of Mississippi River water into the Mississippi Sound resulting in large reductions in salinity, extensive algal blooms and nearly 100% mortality of oyster reefs. Weekly water quality assessments were conducted from June thru August 2019 to measure nutrients, dissolved organic carbon and nitrogen, chlorophyll a, and particulate organic matter as well as the stable isotopic composition of water (δ<sup>18</sup>O and δD) for water source tracking. River water samples had high nitrate concentrations (92 µM) and low ammonium and soluble reactive phosphate (SRP) concentrations (<2 µM). Water isotope results show that water from some regions of the Sound was composed of nearly 50% Mississippi River water. Dissolved inorganic nitrogen (DIN) and chlorophyll concentrations increased by an order of magnitude compared to historical measurements and bottom water hypoxia was measured across large portions of the Sound. No significant increases in soluble reactive phosphate concentrations were observed resulting in high DIN:SRP ratios (50 - 70) in the western Sound. Under normal hydrological regimes, DON represents the largest nitrogen pool in the Sound; however, DON concentrations concurrently decreased with DIN increases while the BCS was open. After the BCS closure in late July, nutrient concentrations throughout the Sound returned to low background concentrations within several weeks.
What is the Value of Drinking Water?
Year: Authors: Barrett J.R.
There may be many perspectives on what is the true value of drinking water and how we quantify that value. One may feel there is no way to quantify the true value of water because it is essential to survive. On the other extreme, one may feel that water is free because you can find it in so many locations at little or no cost. Regardless of the perspectives that may exist, this project examines the realistic view of drinking water compared across the options in which people derive their drinking water. The three options that exist are community water systems, private wells, and bottled water. Community water systems are regulated at the state level by the Mississippi State Department of Health-Bureau of Public Water Supply with guidance from the Federal Safe Drinking Water Act. Private wells have very minimal regulatory oversight and are the complete responsibility of the well owner. Private well regulations are limited to the drilling codes enforced upon the well drillers. Bottled water is regulated by the Food and Drug Administration. Each of these options has its positives and its negatives. This study looks at the real costs to people of providing each of these options and the drawbacks from each option. The desire of the project is to inform citizens of the value of drinking water while considering the potential issues of private wells and the astronomical cost of bottled water.
Lead testing in drinking water at child care facilities
Year: Authors: Barrett J.R.
Lead in drinking water has had heightened attention since the Flint Michigan crisis even though lead has been an issue for years. The EPA has passed the lead and copper rule that regulates and dictates testing for lead in drinking water systems but does not specifically address the most at-risk individuals which are youth under the age of six. This research focuses on child care facilities with a goal of determining best practices to reduce and/or eliminate the expose of lead in drinking water.<br /><br /> Mississippi citizens who acquire their drinking water from public water systems have the luxury of knowing the quality of their drinking water on a regular basis if they know who to contact and/or where to look. Approximately 90% of Mississippi citizens are served by one of the 1,200(+/-) public water systems which provide safe reliable water under the regulatory guidance of the Mississippi State Department of Health-Bureau of Public Water Supply. The regulatory oversight of public water systems should promote and produce a safer drinking water supply for Mississippi residents. Individual residents' plumbing and fixtures may contribute to lead leaching in drinking water regardless of the quality of the water produced and provided by the public water supply. As a result of knowledge gained from applied research, the adaption of best practices by practitioners, parents, and youth will increase the safety and reduce the expose of lead in drinking water for youths.
Triennial review of Mississippi's water quality standards: Updates and revisions
Year: Authors: Felch P.
The Clean Water Act (CWA) requires each State to establish and maintain water quality standards (WQS) to meet the two objectives expressed in Section 101(a), which are as follows: (1) restore and maintain the chemical, physical, and biological integrity of the Nation's waters and (2) wherever attainable, achieve a level of water quality that provides for the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water. Consequently, WQS serve as the foundation for a wide range of water quality management programs under the CWA. WQS serve multiple purposes that include defining the water quality goals for a specific waterbody and providing the regulatory basis for establishing water quality-based effluent limits (WQBELs) beyond the technology-based levels of treatment required by CWA Sections 301(b) and 306. WQS also serve as a target for CWA restoration activities such as total maximum daily loads (TMDLs). <br /><br /> The CWA also requires that each state's WQS contain three components: (1) designated use(s) of the State's waterbodies; (2) the water quality criteria (narrative or numeric) necessary to protect those uses; and (3) antidegradation provisions to protect water quality. Every three years these standards must be reviewed, revised and adopted in a process known as the triennial review. The current triennial review process for revisions to MS's WQS is currently underway.<br /><br /> The proposed modifications are scientifically-based and will allow for effective and improved protection of the state of Mississippi's surface waters and ecosystems. All proposed modifications must have a public comment period and public hearing in order for MDEQ to receive any feedback and comments regarding the proposed revisions. Any proposed revisions to the WQS must be adopted by the Mississippi Commission on Environmental Quality and then approved by the Environmental Protection Agency before they are used by the state for any Clean Water Act programs.
Educational engagement surrounding water quality in Jackson, Mississippi
Year: Authors: Willett K.L., Otts S., Surbeck C., Hopper T.
Through University of Mississippi (UM) Community Wellbeing Constellation funding, our team was able to develop three community engagement initiatives to enhance water quality education in the state. Educational activities included: 1) developing and teaching an honors experiential learning course on drinking water quality; 2) conducting community-based participatory research on residential drinking water; and 3) developing a story map highlighting the water infrastructure challenges in the City of Jackson. The course was designed to familiarize the students with timely issues in drinking water safety and distribution and to use a variety of literature, interviews and media reports to propose solutions to water issues in MS. The students toured and reflected on both the O.B. Curtis Water Treatment Plant and the UM Wastewater Treatment Plant. Two drinking water lead testing events were conducted in Jackson in collaboration with partners at Rosemont Baptist Church and the Mississippi Urban League Baby Café. Twenty-eight samples were tested, and two had concentrations of lead above 5 ppb, which is above the allowable level for bottled water set by FDA. Finally, the team is developing an ArcGIS Story Map outlining and explaining for a general audience the issues surrounding Jackson's drinking and wastewater infrastructure and how those deficiencies contribute to public health problems in the city. With these activities, the UM team continues to work with communities to uncover the link between water quality and health in Mississippi.
A comparative study of common property-based management in Arizona and private property-based management in Mississippi for sustainable water use
Year: Authors: Ko J.
Conflicts over surface and ground water resources in communities have been increasing. Additionally, inter-state disputes over the water resources passing the state borders also have increased, due to increasing water demands from the increasing population, expanding cash crop cultivation, and newly establishing manufacturing facilities in the Southern region including the State of Mississippi. The current water policy in the region is mainly based on the historical legacy of presuming limitless private property. For example, the State of Mississippi has been in legal disputes with the neighboring Tennessee over the groundwater flow near the state border to secure more groundwater. These cases show well serious challenges in designing programs for stabilizing water table in aquafer, and for sustainable water use in state. The presentation will contrast the common property-based management with the private property-based management in water management. The State of Arizona, which has been experiencing rapidly depleting groundwater, has adopted the common-property based water management, mandating estimation of safe-yield and preservation of groundwater for future use. The proposed study examines differences in water policy between Arizona and Mississippi as a way of exploring sustainable water use, while reducing conflicts over the valuable natural resource.
Row Spacing of Alfalfa Interseeded into Native Grass Pasture Influences Soil-Plant-Water Relations
Year: Authors: Dhakal M., West C.P., Deb S.K., Villalobos C., Kharel G.
Interseeding alfalfa (<em>Medicago sativa</em> L.) can improve forage quality of grasslands by adding a high-protein species, but runs the risk of accelerating soil water depletion. The objective was to evaluate effects of cultivar and row spacing of alfalfa on soil water balance and plant water potentials (Ψ) of two upright-type cultivars, NuMex Bill Melton and WL 440HQ, and a prostrate-type Falcata-Rhizoma blend, interseeded into native grasses in October 2015 near Lubbock, Texas. Alfalfa was interseeded at 36-cm (narrow) and 71-cm (wide) row spacings. Soil volumetric water content (VWC) and midday Ψ<sub>stem</sub> and Ψ<sub>leaf</sub> were measured weekly in 2017 and 2018 growing seasons. Soil VWC was not affected by alfalfa cultivars (<em>P</em> > 0.05), whereas alfalfa row spacings differed (<em>P</em> < 0.05). Narrow spacing caused lower (<em>P</em> < 0.05) VWC than did wide spacing relative to the grass-only control in both the upper 40-cm and 40- to 100-cm layers of the soil. Wide row spacing had similar VWC to control in 2017 for both soil layers (<em>P</em> > 0.05). Soil water depletion increased with alfalfa crown density (<em>r</em> = 0.60, <em>P</em> < 0.05) in association with enhanced evapotranspiration and denser root mass below 30-cm soil depth. Grass and alfalfa Ψ<sub>stem</sub> and Ψ<sub>leaf</sub> were depressed in narrow rows relative to wide rows and control, indicating that presence of alfalfa intensified competition with the grass for soil water. The wide-row treatment seldom had adverse effects on grass water stress. Wide row spacing achieved a favorable compromise between enhanced water use and improved stand productivity.
Passively injected air into subsurface drip irrigation system: Plant uptake of pharmaceuticals from human and animal recycled water
Year: Authors: D'Alessio M.
The need for alternative sources of water is dramatically increasing. With the increase in population, there exists a challenge to feed the people by producing crops with relatively less arable land and limited water resources. Where irrigation water is needed for crop production, wastewater (human and/or animal) treatment and reuse represents a challenging but viable alternative and may even lead to increased productivity of soils. Over the past few decades, there has been a significant shift in irrigation technology from surface to pressurized irrigation, including surface and subsurface drip irrigation (SDI). Passively injecting air into SDI systems increases crop yields and overcomes root zone wetting issues. The impact of passively injected air into SDI will be discussed in terms of i) plant growth, expressed in terms of weight, size, and development of the roots plant, ii) uptake of pharmaceuticals from human and animal recycled water, and iii) soil microbial activities. Results from greenhouse investigations and preliminary results from a field investigation will be presented.
Improving dryland soybean yield, water use efficiency, and health of dominant soils across Mississippi
Year: Authors: Feng G., Reginelli D.
Cover cropping is considered to be an effective management practice for improving dryland soybean yield, water use efficiency (WUE) and soil health. There is a growing interest among producers to adopt cover cropping. However, research data comparing the effectiveness of cover cropping under diverse weather conditions are very limited, particularly in the southern United States. It is important because cover crop species provide specific benefits to crops and soils under various weather conditions. Therefore, both field trials and simulation studies were conducted to evaluated dryland soybean yield and water use, properties and water conservation of a silt loam soil from growing wheat cover crop (CC) followed by corn and soybeans under wet, normal and dry years in the northeast Mississippi. Annual total precipitation averaged 1,373mm in the past 8 decades of seasonal years (1938-2017). In wet years (0 < rainfall probability<u><</u>25%), annual precipitation ranged from 1,562 to 2,053 mm, and from 1,120 to 1,545 mm in normal years (25% < rainfall probability<u><</u>75%), and from 821 to 1181 mm in dry years (75% < rainfall probability<u><</u>100%). Average annual precipitation across wet years was 35% (446 mm) higher than that across normal years, and 69% (701 mm) higher than across all dry years. An 80-yr of RZWQM-simulation demonstrated that, during autumn and spring (early October to early April) and compared to no CC scenario, planting CC reduced drainage deep percolation by 69 mm (11%), 53 mm (15%), and 51 mm (21%) and in wet, normal, and dry years, respectively. When averaged across 40 years and compared to no CC scenario, planting CC decreased surface evaporation by 38 mm (24%) and increased main crop soybean transpiration by 15%. Planting CC increased soybean yield by 41 kg ha<sup>-1</sup>; and improved soybean grain WUE by 5%. Cover crops can increase soil organic matter by 15% and storage of rain water in soils by 13% during the crop growing season. Long-term use of winter wheat cover crop, if managed similarly, can reduce deep percolation and increase soil water storage, as well as improve precipitation use efficiency without sacrificing cash crop growth in maize and soybean crop rotations in subtropical agro-systems.
Stream Health and Water Quality Conditions Associated to Livestock Production in the Catalpa Creek
Year: Authors: Ramirez Avila J.J., Chavarro-Chaux L., Ortega-Achury S., Richardson B., Czarnecki J., Schauwecker T.
Physicochemical and biological assessments of stream water quality and health have been advanced along a 0.9-km reach located within the MSU Dairy Unit in northeast Mississippi. The reach, a tributary of the Catalpa Creek, directly receives surface and concentrated (gullies) runoff from the upper 0.52-km<sup>2</sup> livestock drainage area production. A bi-weekly grab sampling of the reach advanced during the summer and fall 2019 evidenced poor water quality conditions of the, in average, 0.4-m depth stream baseflow. The observed water quality impairment along the reach is apparently driven by the presence of cattle in the fields and their direct access to the stream, the potential nutrient enrichment of the shallow water table (which maintains the baseflow level during the dry months of the year), and the supply of sediment from active streambanks along the main stream and tributary gullies. Measured nutrient concentrations (Total Nitrogen: 1.2-2.2 mg/l; Total Phosphorus: 0.27-0.72 mg/l; NO<sub>3</sub>>0.3-0.78 mg/l; Total Kjeldahl Nitrogen: 0.72-1.82 mg/l) exceeded the standard nutrient criteria proposed for Mississippi. Critical levels of dissolved oxygen (DO) (1.6-5.0 mg/l) and water temperatures of up to 34.3°C, exceeding the standard of 32.2°C, were also monitored. The use of macroinveretebrates assessment as indicator of water quality, revealed little macroinvertebrate diversity and also evidenced poor water quality conditions along the reach. Samples were dominated by midge larvae (Family: Chironomidae) and aquatic worms (Subclass: Oligochaeta), both considered indicators of poor water quality when dominant. Other indicators of poor water quality conditions were green blooms and floating cyanobacteria, the latter mostly present along the deeper segments of the reach containing low DO. Monitoring will continue through the implementation of stream crossings and riparian buffers, practices expected to improve stream health and water quality conditions along the monitoring reach.
Effects of biochar incorporation on nutrients leaching in a soil of the Mississippi Delta
Year: Authors: Ortega-Achury S.L., Ramirez-Avila J.J., Chavarro-Chaux L., Anapalli S., Pinnamaneanl S.
The effects of incorporating sugarcane biochar on soil's physical and hydrologic characteristics and leaching water quality is evaluated in the Mississippi Delta. The study has been advanced on ten rain fed corn production plots (1200 ft2) receiving five levels of biochar application (0, 5, 10, 15, 25 Mg/ha). Potential effects on leaching water quality were evaluated by implementing two soil-water samplers on each plot, one at 6-in depth, the second at 12-in depth. Soil physical tests such as infiltration, aggregate stability and bulk density were completed before and after crop growth and harvest to determine potential changes in soil hydrologic response. Preliminary results indicate water transmission increased on amended soils when compared with the fields with no-biochar application. Reductions on total nitrogen and nitrate leaching concentrations ranged from 1.3 to 2.1 times the measured concentrations leached from unamended plots. Maximum measured concentrations observed after the first rainfall event next harvest were 45-mg/l and 27-mg/l for TN and nitrate, respectively. As leaching concentrations of nitrogen decreased in time for all the plots, no significant effect was observed on TN and nitrate concentrations among treatments during the winter period. Phosphorus leaching concentrations were lower on biochar treated plots, but a reduction trend with soil wetting during the wet season was not observed. Phosphorus concentrations on amended plots decreased, on average, from 1.7 to 2.0 times the concentrations observed on unamended fields.
Determining Function-Based Assessments for Streams in Mississippi
Year: Authors: Ramirez-Avila J.J., Ortega-Achury S., Chavarro-Chaux L.
The physical, chemical, and biological processes that create and support a stream system are known as stream function. Understanding how stream functions work together and which restoration techniques influence a given function is a necessary step to successfully restore stream corridors. A study was completed to determine the function-based watershed and reach level assessments, restoration potential, project goals and objectives, and preliminary designs for reaches along tributary streams of the Catalpa Creek in Mississippi. Rating of pre-restoration conditions for hydrology and hydraulics stream characteristics indicate all the streams are functioning at risk due to their flashy response, presence of point flow discharges and limited floodplain connectivity due to their degree of incision. The geomorphology level was rated as functioning at risk and not-functioning due to the limited presence of riparian vegetation and streambed material, and the presence of active streambanks along different segments of the study reaches. Assessment of water quality and macroinvertebrates evidenced that physicochemical and biological processes are functioning at risk due to the effect of seasonal variations in temperature, dissolved oxygen and nutrients contents of the stream water, the significant presence and predominance of macroinvertebrate communities tolerant to impaired water quality conditions, and the limited presence of favorable habitats for good water quality bioindicators. Watershed and reach assessments indicated the restoration potential for all the study reaches should focus on the uplift of hydrology, hydraulic and geomorphology processes. Following the natural channel design guidelines, all the study reaches, currently in a widening and degradation stage on the channel evolution sequence and categorized as Rosgen G stream type, could be restored to become stable Rosgen class C streams.
Single-pot method for the collection and preparation of natural water for microplastic analyses: Microplastics in the Mississippi River system during and after historic flooding
Year: Authors: Scircle A., Cizdziel J.V., Missling K., Li L., Vianello A.
We describe a simple single-pot method for collection and preparation of natural water for microplastic analyses. The method prepares samples in the same vessel (mason jars) that they are collected in right up until the microplastics are transferred onto filters or spectroscopic windows for analyses. The method minimized contamination, degradation, and losses, while increasing recoveries and throughput when compared with conventional sieving. We applied it to surface grab samples collected from the Mississippi River and its major tributaries during and after historic flooding in 2019. Microplastics (>~30μm) were quantified using Nile red fluorescence detection, and a small subset of samples were identified by micro?Fourier transform infrared imaging spectroscopy. Concentrations were lower during the flooding, likely due to dilution. Concentrations ranged from approximately 14 microplastics/L in the Tennessee River during flooding to approximately 83 microplastics/L in the Ohio River during low?flow (summer) conditions. Loads of microplastics tended to increase downriver and ranged from approximately 87 to approximately 129 trillion microplastics/d near New Orleans. Most of the microplastics (>60%) were in the lower size fraction (~30-90?μm) and consisted primarily of fragments (~85%), followed by fibers (~8%) and beads (~7%), with polyester, polyethylene, polypropylene, and polyacrylate as the primary microplastic types. Overall, we demonstrate that the single?pot method is effective and versatile and, because it uses relatively inexpensive and easily assembled materials, can be adapted for microplastic surveys worldwide, especially those involving sample collection by volunteers from the community and schools.
Recent Hydrogeologic investigations at Shellmound MS for the Groundwater Transfer and Injection Project
Year: Authors: Rigby J.R., Kress W., Minsley B.
The USDA is conducting a pilot study to investigate the potential for a managed aquifer recharge project to augment recharge to the Mississippi River Valley Alluvial Aquifer (MRVA). The conceptual design of the project proposes to use riverbank filtration to capture water from the Tallahatchie River for direct injection in the aquifer. The USGS Mississippi Alluvial Plain (MAP) project, as part of a larger regional effort, in collaboration with USDA has contributed extensive high-resolution geophysical investigations to the characterization of the hydrogeology of the project area including Airborne Electromagnetic (AEM) surveys, surface Nuclear Magnetic Resonance (NMR), and towed time-domain electromagnetic surveys (tTEM). The Resolve AEM survey provides the best composite image of the aquifer available to date and at a higher resolution than any previous method. The high-resolution airborne survey mapped an area 15 km by 30 km north and west of Greenwood, MS. Flight lines were oriented east-west and separated by 250m. The AEM provides a spatially extensive data set to help interpret the thickness of the MRVA, the elevation of the aquifer top and bottom, and the nature of material lying above and below the aquifer. The AEM survey results for the study area show the bulk of the MRVA between 10m and 45m below land surface. An extensive electrically conductive unit begins to appear broadly at 40-50 m below land surface in the eastern half of the project area though it is cut by a large-scale channel-like feature of electrically resistive material extending to depths of approximately 80 m below land surface. In the western half of the project area moderately resistive material extends deeper than in the eastern half suggesting the appearance of subcropping Tertiary units in contact or nearly in contact with the MRVA. The AEM survey has also provided extensive data on the electrical properties of the top 10 m of sediment below land surface commonly referred to as the confining layer of the MRVA. This layer is shown to be highly heterogeneous, suggesting that areal recharge from precipitation may also be spatially heterogenous and vary substantially. Results from near-surface methods gives a still higher resolution picture of the upper sediment layers but broadly agrees with results of the high-resolution AEM survey. These methods will be further compared with other geophysical methods and core logs to outline the evolving conceptual framework of the study area for the managed aquifer recharge project.
Increase in Plant Available Water Holding Capacity of Soils Amended by Biochar
Year: Authors: Li Y., Feng G., Tewolde H., Adeli A., Reginelli D.
Biochar as a soil amendment has been increasingly advocated for its effects on improving soil water holding capacity and soil health. To date, little information was found regarding impact of biochar amendment on plant available water holding capacity of dominant soils in Mississippi State. The objective of this study was to investigate whether and how much biochar addition at various rates could improve plant available water holding capacity of dominant soils in the state of Mississippi. Laboratory (Incubation) and field experiments were conducted to measure soil bulk density (BD), total porosity (TP), field capacity (FC), permanent wilting point (PWP), soil moisture characteristic curve (SWRC), saturated hydraulic conductivity (Ksat), and infiltration rate (IR). Then the plant available water holding capacity of soils amended by biochar will be calculated to evaluate the effect of biochar addition on the water use efficiency in Mississippi State.</br></br> The results are expected to provide fundamental guidance for growers, university extension and NRCS personnel, and policymakers to amend biochar for improving water use efficiency of different soils in Mississippi State.
Systematic Water Use Efficiency in Maize-Soybean Rotations: The Impact from Climate Change and Cover Crops
Year: Authors: Li Y., Tian D., Feng G., Feng L.
Climate change influence hydrological processes in agricultural systems, which may lead to inefficiency of systematic water use efficiency (sWUE). Cover crops can be potentially considered as a strategy to improve systematic water use efficiency for mitigating the effects from climate change. However, the potential effects of cover crops on sWUE have not been studied under future climate scenarios. In this study, the hybrid Root Zone Water Quality Model version 2 (RZWQM2) model was calibrated using 5 years (2013-2017) field data. The calibrated model was used to simulate historical and future crop yields, evapotranspiration, seepage, and runoff under the cover crop and non-cover crop scenarios in Pontotoc, Mississippi using historical observations and future climate projections under two Representative Concentration Pathways (RCPs) 4.5 and 8.5 from statistically downscaled outputs of ten GCMs (General Circulation Models) from Coupled Model Inter-comparison Project - Phase 5 (CMIP5). The impacts of cover crops and climate change on maize-soybean rotation systems are analyzed using the model simulations under different scenarios. The results indicated that cover crop decreased the annual seepage respectively 13.7% during 2020 to 2049 and 11.4% during 2050 to 2079 under RCP4.5, by 16.1% and 14.7% under RCP8.5. Compared with the no cover crop management, the sWUE under cover crop management were improved respectively by 3.4% during 2020 to 2049 and 1.8% during 2050-2079 under RCP4.5, and by 3.1% during 2020 to 2049 and 1.5% during 2050-2079 under RCP8.5 for maize but not much for soybean. The results of relationships between climate extreme indices and crop model output variables suggest that the practice of cover crops can reduce the negative feedback effect of high temperature and plays a certain buffering role by improving evapotranspiration in extreme weather.
The Spatiotemporal Variation of Groundwater Level and Response to Landuse Change in the Big Sunflower River Watershed
Year: Authors: Han Y., Feng G., Ouyang Y., Liu Z., Jenkins J.N.
The Big Sunflower River Watershed (BSRW) groundwater was heavily used for irrigating crops. Cotton, soybean, corn and rice account for 64% of the total area in BSRW and their irrigation water use is 0.5, 0.7, 0.9 and 3.0 feet/acre, respectively. The landuse had a huge change and groundwater levels has been decreased over 1 meter from 2003 to 2013. However, the annual rainfall of BSRW in 2003 and 2013 was similar(52.6 and 54.2 inch). The purpose of this study was to study the spatial variation of groundwater level and the relationship between landuse change and groundwater level variation in 2003 and 2013. We applied the semi-variation function model and Kriging interpolation technique to produce BSRW's groundwater level isogram maps in 2003 and 2013. The differences of groundwater level between 2013 and 2003 were spatially displayed across the BSRW. The landuse map of BSRW in 2003 and 2013 were used to obtain the changes of land use patterns and area. The transition matrix of landuse types with respect to different change range of groundwater depth between 2003 and 2013 will help us to understand the relationship between groundwater level and landuse. Our results showed that the planting area of cotton and corn changed dramatically from 2003 to 2013 and groundwater level in BSRW decreased rapidly from northeast to southwest, sunflower county was the center of groundwater decline. The change trend of planting patterns from cotton to corn and soybean had no obvious relationship with groundwater change, but the change from grass/pasture to woody wetland/forest had an effect on groundwater level change.
Control of Chinese Privet as a Part of the Water Resources Management Plan for the Redbud-Catalpa Creek Watershed
Year: Authors: Palmer T., Schauwecker T.
As a part of the Undergraduate Research Scholars Program at Mississippi State University, we investigated the control of the highly invasive shrub Chinese privet (Ligustrum sinense) in the Catalpa Creek Watershed. The goal of our research is to provide management personnel with Standard Operating Procedures (SOPs) for invasive species management. We will also provide a cost-benefit summary for each of the methods for decision-making purposes. Our research compares three methods thought to best control the privet in the field: Cut Stump, Hack and Squirt, and Basal Bark Application methodologies. Eighteen cross sections of the upper reaches of Catalpa Creek, all located on the HH Leveck Research Farm, were sampled for privet cover in 2017. Using this data as a starting point, a privet treatment method was randomly assigned to each of 18 stream cross sections to implement the methods. The Cut Stump method was implemented by cutting through the circumference of the privet 12" or below on the trunk and then immediately applying a 3:1 solution of water and 41% glyphosate. The second method implemented is known as Hack and Squirt, and required a machete or sharp tool to cut around the circumference of the privet 12" or below on the trunk and then immediately applied a 1:1 solution of water and 41% glyphosate. The final method that we implemented was called the Basal Bark method. With this method, we applied a 20% triclopyr herbicide solution with an oil-based surfactant to the bottom 12" of the trunk. Once we had applied the herbicide, we gathered all the cuttings for future use as waddles to help control erosion on another site. For this presentation, we give preliminary results of treatment outcomes based on early spring growth.
The Use of Lumped Parameter Modeling to Determine Groundwater Age of the Mississippi River Valley Alluvial Aquifer
Year: Authors: Wacaster S.R., Knierim K.J., Kingsbury J.A., Killian C., Bussel A., Kress W., O'Reilly A.M.
Groundwater from the Mississippi River Valley Alluvial (MRVA) aquifer supplies water primarily for irrigation and domestic uses in the Mississippi Alluvial Plain (MAP), so understanding how water quality influences availability is critical for states relying on this important resource. Additionally, deeper aquifers such as the Sparta aquifer are used for public drinking-water supply and there are questions about hydraulic interaction between the aquifers. Surface-derived contaminants are more likely to affect groundwater that contains a greater fraction of young water, so determining groundwater age is important when assessing groundwater availability within the context of water quality and how it might change over time. In the MRVA aquifer, 39 wells were sampled from July to December 2018 for inorganic constituents and age-date tracers. Local-scale groundwater studies have been conducted in the MRVA aquifer, but a regional characterization of groundwater age is needed to gain a better understanding of recharge processes and how water quality varies with groundwater age. This research will determine groundwater age of the MRVA aquifer, which underlies a large portion of the MAP extent, using a lumped parameter model using age-tracer data (tritium, helium, sulfur hexafluoride, and carbon-14) collected by the U.S. Geological Survey (USGS). These calculated ages can be used to better estimate recharge for the water budget of the MAP area, which in turn will aid in model predictions of future groundwater availability. Groundwater ages from the Sparta aquifer will be used to assess groundwater interaction between the aquifers where confining units are absent. Preliminary analysis of tritium data collected for this project from samples in the MRVA aquifer indicate that about half of the locations sampled contained little to no young groundwater (defined as younger than 1950). This suggests portions of the MRVA aquifer are being recharged very slowly, thus causing a longer-term imbalance of recharge and withdrawals.
DSS based BMPs effectiveness impacts and evaluation of water quality at Yazoo River Sub basin
Year: Authors: Shabbir M.
The web based support systems are one of the emerging interdisciplinary study with the motivated challenged and opportunities. It focuses on the tool and design implementation of web based support systems and various other human activities. With the emergence of web technologies and web based support system, various support system has been extended from single machine to a single computer system user. The recent advancements of technologies such as water quality management practices (BMPs) and low impact development practices (LID) are reducing the amount of adverse influences on urban areas. The objective of this study is to evaluate the effectiveness in sub basin watershed with the (L-THIA) web application, a DSS (Decision support system) based integration web based programs and geographic information system (GIS) for intended to support decision makers who need information regarding BMPs and LID effectiveness practices on water quality and land uses changes. In agriculture field, decision-making perception for used land, which can include changes in agricultural uses in an area or adaptation to non-agricultural uses. However, DSS is targeted to beginner should provide additional functionalities to help understanding the results. L-THIA model estimates the long term average yearly runoff for the land use types in required watershed based for long term climate data, soil and land use data for that area. By using more than sixteen years of daily precipitation data in daily runoff calculation alongside with curve number method, L-THIA gives long term effects, rather than an extreme year or storm event impact. These development can support and guide consumers in verdict creation and increase consumer's ability to understand the land use changes on water quantity and quality. Keywords: L-THIA, DSS, BMPs, LID, Soil data
Experimental study of the performance of the N,N'-di (carboxymethyl) dithiocarbamate chelating resin in removing heavy metals from oilfield waste wate
Year: Authors: Al Otmi M., Mirabolghasemi M.
High concentrations of heavy metals in oilfield waste water pose serious health and environmental risks. These risks can be partially managed by waste water treatment for repurposing. Treating oilfield waste water at large volumes remains a challenge due to the high concentration of heavy metals and their variety. In this study, we examine the capability of the N,N'-di (carboxymethyl) dithiocarbamate chelating resin in removing divalent heavy metal ions. We also test the effect of the presence of multiple types of ions and hydrocarbon content on the adsorption of each metal. The resin is synthesized following a multi-step procedure outlined in the literature. We verified the accuracy of the synthesis procedure by comparing the removal of single metal ions (Pb, Cu, Ni) measured in the lab, with the values reported in the literature. Next, the performance of the resin is tested in terms of metal removal efficiency as a function of time, for solutions of two metal salts. We expect to observe hindered adsorption due to the competition between the ions. The concentration of metals are measured by solution conductivity measurement and Raman spectroscopy. This study quantifies the metal removal power of the N,N'-di (carboxymethyl) dithiocarbamate chelating resin under various conditions. This information is useful for comparing various methods of oilfield waste water treatments based on their efficiency and operational costs.
A Geospatial Inventory of Surface Water for Irrigation in the Big Sunflower River Watershed
Year: Authors: Brock M.L., Tagert M.L., Paz J.O., Krutz L.J.
The Delta is the center of agricultural production in the state of Mississippi. This region harbors a humid climate with approximately 55 inches of rainfall per year. However, seasonal variability in precipitation with only 30% of rainfall occurring in the growing season requires the use of irrigation systems to meet crop water needs. As groundwater has been the predominant water source for irrigation, extensive pumping of the Mississippi River Valley alluvial aquifer has led to concerns over the sustainability of groundwater. On-farm water storage (OFWS) systems have been implemented in different areas throughout the Delta as a conservation practice to mitigate nutrient runoff and address water quantity concerns. These systems consist of a tailwater recovery ditch that collects irrigation and rainfall runoff and conveys the water to a storage pond for reuse. Using surface water as an alternative to or in conjunction with groundwater shows promise of releasing the strain on groundwater sources in certain areas. Through this project, an inventory and analysis of OFWS systems in the Big Sunflower River Watershed (HUC 08030207) is being conducted using high-resolution imagery and geospatial technologies such as ERDAS IMAGINE image analysis software. In the inventory, storage ponds and tailwater recovery ditches are delineated and simplified into polygons to create functional shapefiles of existing OFWS systems. Preceding years are then evaluated to discover the rate of construction of OFWS systems in the Big Sunflower River Watershed in response to various factors.
Investigating Variables Which Could Affect Unionid Abundance and Biodiversity
Year: Authors: Kunberger J.M., van Ee B.C., Atkinson C.L.
Freshwater mussels (order Unionoidea) are crucial to the health of freshwater ecosystems, as they filter water and excrete easily consumable materials. Due to drought, pollution, and development of river systems, Unionids are imperiled with over half considered endangered and many already extinct. Despite their importance and the pressing threat of more extinctions, research into Unionid habitat selection is limited, with only a handful of scientists working on pinpointing the factors that determine Unionid presence and success. This research would be valuable in determining how to detect potential areas of Unionid success and to predict impacts on certain populations, which would both aid in management and reintroduction efforts. In this study we surveyed six sites in the Sipsey River, which is known for its high Unionid diversity and abundance, and investigated variables at three spatial scales to determine which factors could be relevant in Unionid habitat selection. During the survey, we collected quadrat-level data at each site, including mussel abundance and biodiversity, pH, temperature, flow, and sediment characteristics. We also collected site-level data, including active channel width, seston quantity, discharge, and hyporheic flow. Lastly, through the use of remotely-sensed imagery and GIS operations, we determined watershed extent, distance upstream, vegetation, and land use for each site as landscape-level data. We then performed statistical analyses to determine which factors would best explain abundance and biodiversity at these sites.
Iron-precipitation in Mississippi streams from discharge of iron-rich groundwater: characterization and modeling
Year: Authors: Herath H., Davidson G., O'Reilly A., Widanagamage I.
Some streams in northern Mississippi experience extensive precipitation of ironminerals on bottom sediments and plant matter, resulting in diminished photosynthetic production and biological diversity. At two streams, one with visible iron-precipitates and one without, two shallow wells were installed along a groundwater flow path toward each stream. Both streams and wells were sampled for water quality. Physicochemical parameters such as pH, water temperature, conductivity and dissolved oxygen were measured in-situ. Titrations were performed to measure in-situ alkalinity. Total Fe concentration in the water was also measured in the field using a photometer. Major and minor ion concentrations were measured at both locations and possible mineral phases were identified using geochemical modelling software (PHREEQC-3.4.0-12927). Some groundwater samples showed elevated levels of NO<sub>3-</sub>, Al, As, Na, and P. Hardness at one site is soft-moderate while at the other it varies from soft to hard. Water overall can be classified as dominantly Ca-Cl. Generally, all groundwater significantly exceeded the U.S. Environmental Protection Agency secondary drinking water standard of 0.3 mg/L for Fe. The concentration of Fe tends to decline along the groundwater flow path exhibiting an inverse relationship with pH and dissolved oxygen. Fe is depleted in both streams due to prevailing oxidizing conditions which promote transformation of Fe(II) to the less soluble Fe(III). All waters at both sites are supersaturated with respect to hematite, goethite, gibbsite, K-mica and kaolinite. Based on geochemical modeling, Fe precipitation is favored in both streams. However, iron-oxyhydroxides are only visually observed in one stream. Explanations for the absence of observed precipitates in the second stream may be related to differences in stream size. In the larger stream, greater dilution of groundwater discharge occurs (lower measured Fe), and higher discharge rates may retain precipitated minerals in the water column to flush them downstream.
Runoff and Transportation in Conservation Management Systems under Simulated Rainfall
Year: Authors: Spencer D., Krutz J., Locke M., Ramirez-Avila J., Henry B., Golden B.
Mid-southern, USA silt loam soils are characterized by poor soil structure, increasing their susceptibility to crusting and erosion. Cover crops may improve soil structure through the addition of organic matter thereby increasing infiltration and reducing erosion. Studies were established in Stoneville, MS in 2017 and 2018 to determine the effects of four cover crops on aggregate stability, infiltration, and nutrient and sediment transport under simulated rainfall. Experimental design is a randomized complete block with four replications. Treatments include a reduced till/no cover (as a control), reduced tillage with cereal rye (Secale cereal L.), reduced tillage with Austrian winter pea (Pisum sativum L.), reduced tillage with tillage radish (Raphanus sativus L.), reduced tillage with crimson clover (Trifolium incarnatum L.), and no till/no cover. Results including soil quality parameters, infiltration, and nutrient and sediment transport will be presented.
Characterization of Runoff Water Quality from Established BMP Soybean Production Systems
Year: Authors: Bryant C.J., Krutz L.J., Locke M.A., Steinriede Jr. R.W., Spencer G.D.
Recent regulation has placed even greater pressure on agricultural producers to implement non-point source pollution controls on production fields. The most commonly adopted controls are on-farm best management practices (BMPs) which aid in reducing off-site transport of sediment and agro-chemicals in runoff water. In 2004 a long-term study site was established in the Mid-Southern USA at the Delta Research and Extension Center in Stoneville, MS on a Dubbs silt loam. This study site is used to evaluate off-site transport from furrow-irrigation events under varying BMPs. Experimental units are hydrologically separated from one another and instrumented to mass balance the off-site transport of water, sediment, and agrochemicals. In 2015 the site was transitioned into continuous soybean (Glycine max) production. Treatments included conventional tillage/winter fallow (CT/WF), reduced tillage/winter fallow (RT/WF), reduced tillage with in row sub-soiling (RT/SS), reduced tillage with a cereal rye (Secale cereal) cover crop (RT/RC), reduced tillage with a tillage radish (Raphanus sativus) cover crop (RT/TR), zone tillage/winter fallow (ZT/WF), and zone tillage with a tillage radish cover crop (ZT/TR). Total solids transport was reduced by at least 17% when using a zone tillage system or including sub-soiling or a cereal rye cover crop in a reduced tillage system. Compared to the regional standard RT/WF orthophosphate transport was reduced by at least 35% with a tillage radish or cereal rye cover crop. Including either cover crop or sub-soiling in a reduced tillage system reduced total Kjeldahl nitrogen transport by at least 20%. This data indicates that runoff water quality can be improved through adoption of BMP based soybean production system.
Determining Ecosystem Function and Thermal Thresholds of Freshwater Mussel
Year: Authors: van Ee B.C., Atkinson C.L.
Consumers play a significant role in the uptake, transformation, and storage of nutrients and organic matter in aquatic ecosystems. By creating hotspots of bioavailable nutrients consumers can stimulate ecosystem processes essential to the natural functioning of a system. In addressing the impacts of global climate change it is imperative to understand how these consumer driven processes might be altered under current climate predictions, though this can often be difficult due to the species-level traits relevant in these processes. For consumers, such as freshwater mussels, which are already experiencing drastic declines, studies into ecosystem function can also provide valuable information for conservation efforts. In our study we investigated how physiological rates relevant to ecosystem functions vary across temperatures in multiple species of freshwater mussels. We measured filtration rate (capture of chlorophyll), metabolism (O<sub>2</sub> consumption), excretion rate (release of ammonia and phosphorus), and biodeposition rate (release of solid waste) at a range of temperatures (10, 20, 30°C) for 11 species of freshwater mussels native to the Sipsey River, AL. Using the measured rates, we investigated species-level differences in organic material capture and nutrient release between species. Pairing this with survey data from the Sipsey River, we calculated the filtration capacity of freshwater mussel communities at different times throughout the year. We also used these data to examine the thermal tolerances of freshwater mussel species. By estimating at which temperature these species metabolism shift between anabolism (net gain of energy) and catabolism (net loss of energy), we determined when species growth is inhibited by temperature. The higher the temperature this shift occurs at, the more thermally tolerant a species is considered. Using this information we can estimate which species would be lost first as a result of warming and the potential losses to ecosystem function.
"One pot" Method for Collection and Preparation of Microplastic
Year: Authors: Scircle A., Czidziel J., Li L.
In microplastic analyses, one of the most commonly encountered challenges is how to avoid sample contamination and minimize losses during sample preparation steps. Contamination can be addressed through a combination of vigilant laboratory cleanliness and conscious decisions on materials used and worn during analysis, and losses can be minimized by decreasing transfer steps. However, there still exists a very real chance of contamination, carry-over, or loss events which limits any conclusions drawn. Here, we describe a "One-Pot" method which minimizes sample contamination and avoids transfer losses and carry-over events by keeping a sample in the same jar it was collected in until the sample is placed on a microscope slide for analysis (this includes sample preservation, storage, digestion, density separation, and dye-staining steps). Furthermore, this method uses relatively inexpensive and easily purchased or assembled materials such as canning jars and wire screens. Overall, the "One-Pot" improves reliability of microplastic analyses, particularly for the smaller size fraction (less than about 0.5 mm) which are more prone to contamination and transfer losses.
Assessing the Environmental and Educational Value of an Agricultural Stream Restoration
Year: Authors: McCrary A., Baker B., Burger L.
Agriculture is the predominant source of today's environmental challenges, including the degradation of water resources. With a majority of land in the United States being designated for agricultural use, water resource conservation has become a significant topic of interest for federal and state natural resource agencies. Through the U.S. Environmental Protection Agency's Section 319 Program and the Mississippi Department of Environmental Quality, Mississippi State University is conducting a stream restoration project within its agricultural research properties in Oktibbeha County, Mississippi. This study will evaluate the impacts of the restoration on the impaired stream in an agricultural landscape. Water sampling during storm-runoff events will be conducted to test for changes in microbial, nutrient, and sediment concentrations pre- and post-restoration. Stream flow will also be monitored to assess the volume of water flowing during comparable storm events and calculate the total volume of nutrients and sediments lost from the landscape during events. In addition to these water monitoring activities, a regional survey of Cooperative Extension Service agents with agriculture and natural resource responsibilities will be conducted to assess the need for in-service training on water resource conservation topics. Both water quality monitoring and survey data will be used to evaluate the creek restoration's environmental impact and value as a demonstration site for future stakeholder training in water resource conservation.
Bottom-up Effects of Leaf Litter Conditioning on Snail Physiological Rates
Year: Authors: Glisson L.C., Dickinson G.K., Rankin A.A., Halvorson H.M., Atkinson C.L.
The relationship between food quality and physiological rates is crucial in understanding how invertebrates respond to their environment via bottom-up effects. We investigated the feeding habits of the snail Planorbella trivolvis by altering the microbial conditioning of Typha latifolia leaf litter. We conditioned litter in either a light or dark environment and at high or low nutrient availability to give us four combinations of food quality to assess snail physiological feeding processes. During the two-week feeding study, we measured consumption, egestion, excretion (ammonia, phosphate, dissolved organic carbon, and total nitrogen), survivorship, and instantaneous growth rates. We predicted that the snails would exhibit compensatory feeding, where organisms increase their ingestion of low nutrient food to reach their nutritional requirements. Therefore, we hypothesized that consumption and egestion rates would be increased in low resource quality litter and higher growth rates of snails would be observed in higher quality litter. Our results show that instantaneous growth rates were twice as high in light treatments and consumption rates were four times higher in low nutrient treatments. When examining ammonia excretion rates, significant increases were found in the low nutrient/light treatments and high nutrient/dark treatments. Our results suggest that invertebrates exhibit compensatory feeding to reach their nutritional requirements and prefer higher quality food to maximize growth rates.
Estimating the Optimal Water Requirement for Soybean Production in the State of Mississippi
Year: Authors: Li X., Feng G.
Determining the optimal water amount required for soybean production is a critical step to optimize irrigation management. Previous studies mainly used field experimental data or simulation data from process-based crop growth models. But results based on those data are not always applicable to the real world production fields. This study uses the actual historical data of dryland soybean production from the state of Mississippi to estimate the soybean water response. Given that the precipitation is the only source of water supply, rainfalls are generally random across years, this dataset can be viewed as a natural experiment of soybean water response. Soybean yield data are collected from the USDA RMA (Risk Management Agency) for 76 out of the 82 Mississippi counties spanning the period 1991 to 2014. Precipitation data are obtained from the PRISM (Parameter-elevation Relationships on Independent Slopes Model) Climate Data at 4 km grids and then aggregated to county level. A piecewise nonparametric quantile regression is utilized to estimate how the potential soybean yield changes with precipitation level. Our interest is the conditional quantiles (upper 99%, 95%, and 90%) of yields rather than the mean yields. That is because at a given precipitation level, the yields can still be limited by other growing factors such as temperature, disease, pest, weed, management, technology, and so forth. The more useful information for producers is what maximum yields can be possibly achieved under a certain amount of water supply, given that all other factors are properly managed. The results show the potential soybean yields first increase with precipitation, and reach maximum at the range of 800-1000 mm. After that, the potential yields decrease when precipitation further increases. At low precipitation level, such as under 400 mm, the potential yields are around 35 bu/ac. With adequate precipitation, such as 800 mm, the potential yield can reach up to 55 bu/ac. But excessive precipitation causes potential yields to drop again. The optimal precipitation also varies with temperature. In cooler years (average daily temperature below 23°C) the optimal precipitations are around 700 mm, while in warmer (average daily temperature above 23°C) the optimal precipitations are slight above 800 mm. Those findings provide useful guidelines for optimal irrigation water requirements for Mississippi soybean production.
Characterizing phosphorus fractionation in Delta soils
Year: Authors: Stevens E., Yasarer L., Locke M.A., Taylor J.
As a historical floodplain of the Mississippi River, MS Delta soils are anticipated to have high natural nutrient content. In addition, years of farming and fertilizer applications have altered natural nutrient compositions and potentially created a legacy storage of soil phosphorus on agricultural land. As phosphorus-rich sediment erodes and is transported throughout the landscape, it may be stored in ephemeral drainage paths, ditches, and retention ponds, where it could potentially release phosphorus into the overlying water. This study is the first step in a series of analyses and experiments to characterize and quantify legacy soil phosphorus in a variety of land management types within a Delta watershed. Soil and sediment samples were taken from two locations in five different environments: cropland, Conservation Reserve Program (CRP) land, ditches, riparian forest, and a sediment retention pond. Sampling locations within these land types were chosen based on low elevation and the potential to experience ephemeral flow or elevated soil moisture throughout the year. Samples were taken in triplicate to total 30 samples, which were each homogenized in the laboratory. A series of sequential phosphorus extractions were then performed on field-moist, dried, and flooded samples. Extractions involved: water-soluble fraction, labile P (KCl), aluminum and iron bound P (NaOH), calcium-bound P (HCl), and total P. The field-moist samples were processed immediately, while the dried samples were air-dried for several weeks, ground, and sieved to less than 2mm. Both field-moist and dried samples were extracted in aerobic environments. The flooded samples involved sampling field-moist soil/sediment into a jar with 70mL of overlying water and incubating at 24C for about 50 days to obtain anoxia. Flooded samples were then extracted in an anaerobic environment for the water-soluble and labile fractions. This analysis will help to understand how the hydrologic conditions in these different environments affect P fractionation, which can influence mobility and reactivity with overlying water.
Establishment of a Riparian Buffer along the Constructed Levees of Catalpa Creek
Year: Authors: Lang D., Maddox V.
Riparian buffers along streams that have been channelized to facilitate developments provide filtration of sediments. Their implementation needs to be coordinated with remediation of storm water diversion structures upstream such as constructed wetlands and containment ponds. Constructed levees have been implemented to control floods and to create usable lands for agriculture and other human activities. A constructed levee tends to limit flood plain overflows and it interferes with natural stream ecosystem function. Floodplain overflows deposit alluvium to redistribute upstream sediments dislodged by natural and man-made activities such as from agricultural fields or from impervious surfaces created by construction projects. The constructed levee system of Catalpa Creek originates near its headwaters on the campus of Mississippi State University continues onto the Leveck Animal Research Center into Sessums, MS through Oktibbeha County. These levees and other improvements have created experimental research and educational facilities on the Leveck Animal and Foil Plant Science Research Centers of the Mississippi Agricultural Experiment Forestry Station (MAFES). Waters of Catalpa Creek flow through Oktibbeha County under US 82 through Lowndes County into the Tombigbee River near Columbus, MS. The original channelized levee system provided flow of storm waters from an agricultural landscape historic to the foundations of the Mississippi Agricultural College founded in 1862 as a Land Grant Institution. As Mississippi State University developed into a major comprehensive university, lands that had infiltrated much of the storm water was now covered with buildings and other impervious surfaces such as parking lots. Storm water flow from MSU and neighboring private developments have increased the flood potential of downstream soil resources from "Occasional" to "Frequent". Channelized levee banks constructed in the mid-1930's reached a stable equilibrium down to the Selma Chalk streambed. The Marietta soil has a stable silty clay regolith layer above the Selma chalk (limestone) that has formed a stable erosional environment. Only the constructed levee portion has been subject to erosional bank scours at constructed nick points such as intruding pipes or at bridges. These scours have increased and will continue without abatement of excessive storm water flows from MSU and neighboring private developments as Catalpa Creek seeks to establishment a new equilibrium. A vegetative buffer by itself will not suffice. An alternative vegetative plan would be to cease mowing along the narrow exotic grass strips and allow natural vegetation to volunteer. Strategically located release points would alleviate excess flow in the main channel of Catalpa Creek and its West Catalpa Creek tributary. This will reduce mowing costs and suppress exotic grasses that rely on abundant sunshine and nutrients released by mowing. Two studies with native species volunteering nearby Catalpa Creek will be presented. These indicate that Andropogon sp. will readily volunteer and that most volunteer species are native (> 80%; 11 of 14 were natives).
Overview of Surface Water Resources in Northeast Mississippi
Year: Authors: Henley L.
Mississippi water law (§ 51-3-1) calls for the conjunctive use of both surface water and groundwater so that, to the fullest extent possible, the ground and surface water resources within the state shall be integrated in their use, storage, allocation and management. The Monitoring Branch of the Water Resources Division in the Office of Land and Water Resources (OLWR) at the Mississippi Department of Environmental Quality (MDEQ) characterizes both surface and groundwater resources to inform permitting decisions. There is a large amount of surface water available for use in northeast Mississippi, primarily the Tennessee Tombigbee Waterway, which is a man-made waterway comprised of river, canal, and divide sections that encompasses approximately 234 navigable miles between the Tombigbee River at Demopolis, Alabama and the Tennessee River at Pickwick Lake. Authorized by Congress in 1946 as a means of commercial navigation, construction was completed for the project in 1985. In addition to being used for commercial navigation, the Tennessee Tombigbee Waterway is used for recreation, fishing, a habitat for wildlife, and a source of water for several cities, towns, and industries.
Management of Water Resources in Northeast Mississippi
Year: Authors: Sorrell K.
The Office of Land and Water Resources (OLWR) is responsible for the management of the water resources in Mississippi. § 51-3-1 of the Mississippi Code requires that the water resources of the state be put to beneficial use to the fullest extent of which they are capable, that the waste or unreasonable use, or unreasonable method of use, of water be prevented, that the conservation of such water be exercised. In order to achieve this, the Permitting, Certification, and Compliance Division of OLWR utilizes water availability and use data to determine the viability of new groundwater and surface water withdrawal points, allowed permitted volumes for new and existing groundwater and surface water withdrawal permits, and restrictions on permitted uses. Both surface water and groundwater are used in Northeast Mississippi to meet the demand of multiple beneficial uses.
Comprehensive Approach to Characterizing Groundwater Resources throughout Mississippi
Year: Authors: Banks J.
The Office of Land and Water Resources (OLWR) is charged with conserving, managing, and protecting the water resources of Mississippi. Sufficient spatial coverage of water level monitoring within a short period of time is critical to the characterization of an aquifer. The Monitoring Branch of the Water Resources Division developed a comprehensive plan to provide OLWR with a detailed view of water levels in the state's major drinking water aquifers by starting in the northeast corner of the state and working to the south and west. Work to measure these water levels throughout Mississippi is being accomplished as efficiently as possible by utilizing all staff in the Branch to focus on monitoring in one area at a time. This work also accomplishes the Monitoring Branch goals of characterizing available water resources in prioritized municipal areas throughout the state each fiscal year. The prioritized areas being studied for fiscal year 2019 are the Ripley aquifer, the Coffee Sand aquifer, the Eutaw-McShan aquifer, and the Gordo aquifer, which are drinking water sources for much of northeast Mississippi, including the cities of Starkville, Amory, and New Albany.
Overview of Groundwater Resources in Northeast Mississippi
Year: Authors: Brister A.
The Monitoring Branch of the Office of Land and Water Resources (OLWR) within the Mississippi Department of Environmental Quality (MDEQ) is tasked with monitoring the state's groundwater and surface water resources so that the resources can be put to beneficial use while also being protected. A survey of groundwater levels was completed in 2018 in the Paleozoic and Cretaceous aquifers, which are utilized in twenty counties in the Northeastern area of the state. Water levels were collected by a team of geologists and engineers using methods involving steel and electric tapes from which new potentiometric maps, hydrographs, and cross-sections were created. Changes in water levels across the area of investigation are identified and quantified with areas of significance being highlighted and further investigated. This information is utilized by the Permitting, Certification, and Compliance Division of OLWR to inform the management and permitting of the use of groundwater and surface water resources.
Models Supporting Decision Making: The USGS Mississippi Alluvial Plain project
Year: Authors: Hunt R.J., Pindilli E.J., Fienen M.N., Kress W.H.
The US Geological Survey (USGS) is commonly asked to provide science to inform societal decision-making, including numerical models. Twentieth Century workflows emphasized paper reports and or single discipline information to those charged with making decisions. Such workflows are ill suited for today's decisions, especially those involving adaptive management or large uncertainties. Moreover, as stakeholders have grown accustomed to near instant access to information such as real-time weather forecasts, water-resource support systems have not kept pace. This is the context within which local stakeholders initiated the USGS Mississippi Alluvial Plain (MAP) project in 2016. From its inception, effort was dedicated to formulating a new approach of applying USGS models to decision support involving: 1) dynamic, sophisticated hydrologic-economic model integration, 2) reusable script-based model construction modules; 3) automated conduits that move new field data to the model; 4) high-throughput computing to update calibration and uncertainty outputs; 5) fast-running surrogate models; and 6) web-services suitable for feeding decision-support systems designed by others. The overarching goal is to provide responsive, consistent, and seamless high-quality science even as the decision-making landscape evolves. Challenges to this vision include building an approach that encompasses moving projection targets, ensuring scientific reproducibility, developing a common technology and language across a large, multidisciplinary team, and robust script design extensible for new data types and numerical code updates. However, by the end of the MAP project we believe the workflow and supporting documentation developed will have transferability to many areas outside the MAP.
Substitution between Groundwater and other Inputs in Irrigated Agriculture in the Mississippi Alluvial Plain: An Economic Analysis
Year: Authors: Alhassan M., Lawrence C., Pindilli E.
The Mississippi Alluvial Plain (MAP) region consists of parts of Mississippi, Arkansas, Illinois, Kentucky, Louisiana, Missouri, and Tennessee and relies on the Mississippi River Valley Alluvial Aquifer (MRVAA) for approximately 90 percent of its irrigation water. Irrigated agriculture is the main source of economic activity in this region, with regional economic impact of more than $11 billion from production of major commodities in 2017. However, groundwater levels in the underlying aquifers have declined due to long-term excess pumpage over inflows. These declining groundwater levels result in decreases in well yields, and reduction of water in storage in the aquifers to meet future demands and sustainable use.</br></br> To support decision making regarding groundwater availability and use in the region, this study examines relationships between groundwater, labor, fertilizer use, and irrigation systems (furrow and center pivot) as the main inputs in the production of the major crops (corn, cotton, rice, and soybeans) in the region. In general, understanding relationships between groundwater and other inputs in agricultural production helps decision makers in sustainable management of groundwater. Our study also investigates how changes in water budget components impact input groundwater use in the region. This study employs a translog cost function, a type of econometric model, to analyze the production relationships between the inputs. The model relies on a large dataset of input prices, outputs of corn, soybeans, cotton, and rice, and the hydrologic characteristics of the underlying aquifer. We use 2017 county-level data from USDA-NASS, Crop Enterprise Budgets and Planning Budgets from the University of Arkansas and Mississippi State University, and a combination of observation and model-based hydrologic data. Our preliminary results using state-level data show an inelastic price elasticity of demand for groundwater and inelastic cross-price elasticities of demand between groundwater and the other inputs.
Geophysical Data Integration for the Shellmound Inset Groundwater Flow Model of the Mississippi Alluvial Plain
Year: Authors: Guira M.N., Peterson S.M.
The U.S. Geological Survey Mississippi Alluvial Plain project is updating groundwater models of the Mississippi Embayment and Mississippi River Valley Alluvial aquifer to provide key information and decision support for stakeholders through a decision support system. Groundwater withdrawals from the Mississippi River Valley Alluvial aquifer sustain agricultural production in the Shellmound, Mississippi area, but groundwater declines have heightened concerns about long-term sustainability of the resource and led to consideration of artificial recharge or other water management activities. To support evaluation of the effects of potential water management activities in the Shellmound area, aquifer characteristics derived from high-resolution airborne electromagnetic surveys (AEM) are being integrated into a groundwater flow model. The Shellmound model area is about 1000 square kilometers covering part of northwestern Mississippi.</br></br> Aquifer characteristics derived from the AEM data at multiple resolutions will be objectively evaluated through automated groundwater model calibration, for example, using 1 layer to represent the alluvium as opposed to ten. Each model will use the same hydrologic input data and be calibrated against equivalent calibration targets. Subsequent comparison between model calibration data and simulated outputs for variously-resolved groundwater flow models will provide information about the level of detail in the vertical discretization that most improved the Shellmound Inset groundwater flow model. The comparison will also provide information about the maximum level of detail in the vertical discretization that can be supported from the AEM and supporting data available for model calibration.
Torpedograss Vontrol via Submersed Applications of Systemic and Contact Herbicides
Year: Authors: Turnage G., Wersal R., Madsen J.
Torpedograss (Panicum repens) is a perennial invasive aquatic plant species native to South America that is spreading across the southeastern US. Torpedogass can survive in terrestrial and aquatic environments rooted to hydrosoil or form large floating islands (tussocks) that can limit human and wildlife uses of waterbodies. Portions of tussocks can break off, float away, and start new torpedograss infestations in other locations thereby making the problem worse. Limited data exist concerning submersed chemical control (herbicides) methods that are effective at controlling torpedograss. This work was conducted to investigate short- and long-term submersed chemical control options of torpedograss grown in outdoor mesocosms near Starkville, MS. Nine herbicides labeled for use in aquatic environments and a non-treated reference were evaluated. Eight weeks after treatment (WAT), harvested plants were separated into root/rhizome and shoot/leaf tissues, placed in labeled paper bags, dried in a forced air oven for five days at 70C, then weighed. None of the herbicides significantly reduced root/rhizome tissues for torpedograss eight WAT, however penoxsulam, topramezone, flumioxazin, and carfentrazone-ethyl had reduced root/rhizome tissue by 52 WAT (57%, 64%, 97%, and 62% reduction, respectively). Triclopyr, diquat, flumioxazin, and carfentrazone-ethyl had reduced shoot/leaf tissue at eight WAT (57%, 47%, 98%, and 49% reduction, respectively). At 52 WAT, penoxsulam, topramezone, flumioxazin, and carfentrazone-ethyl had reduced shoot/leaf tissues by 49%, 66%, 97%, and 57%, respectively. While no herbicide treatment reduced root/rhizome biomass below pre-treatment levels, flumioxazin did reduce shoot/leaf tissues below pre-treatment levels. This work suggests that submersed applications of penoxsulam, topramezone, flumioxazin, or carfentrazone-ethyl can provide long-term control of torpedograss populations.
Experimental Evaluation of Herbicides for Chemical Management of Nuisance Native Aquatic Plants
Year: Authors: Ervin G.N., Turnage G., Calhoun K.
Resource managers of public lands, such as national wildlife refuges, manage their lands not only for the resident fish and wildlife species, but also for patrons who utilize those resource areas. Occasionally, the dominance of problematic native plant species interferes with the intended uses of these areas. One example of this is when dense growth of aquatic vegetation blocks access to or effective use of waterbodies. In Mississippi and adjacent states, native plant species, such as Nelumbo lutea or Limnobium spongia, sometimes reach nuisance levels; however, few methods are currently known that allow the control of problematic native plant species such as these.</br></br> Our work is aimed at evaluating several chemicals for their potential to manage these plants in a way that mitigates their negative impacts on recreational use, while also minimizing potential negative impacts on water quality and desirable native plant species. We are conducting mesocosm studies to evaluate six systemic herbicides and one contact herbicide (at two dosage levels each) for their potential to control four target plant species (the above-mentioned two plus Nymphaea odorata and Brasenia schreberi).</br></br> During the first 3 weeks after treatment (WAT), we observed rapid response to some of the herbicides and dosages being evaluated. At that point, all three modes of action included in the study had shown at least 50 percent mortality on all four of the species included in the study, with only two chemical species combinations not reaching 50 percent mortality within 3 weeks. In fact, 2,4-D, Glyphosate, Triclopyr, and Flumioxazin all caused 50 percent mortality of three of the species during the first week, with other chemicals causing 50 percent mortality of the fourth species within the first WAT. At 8 WAT, we still saw continued control of all species except fragrant water lily, based solely on leaf count data. Additionally, we found that, although some herbicides caused a pulse of nitrate concentrations at 4 weeks after achieving 50% mortality, those nutrient concentrations recovered to levels comparable to untreated tanks over the ensuing 4 weeks. We did not find any other evidence of potential negative impacts on water quality in any of the treatments.
Survey of Aquatic Plant Species in Mississippi Waterbodies
Year: Authors: Shoemaker C., Turnage G.
Mississippi has significant water resources that, many times, are impaired by invasive aquatic and wetland plant species. These plants can impact water quality (DO, pH, turbidity, etc.) such that native flora and fauna are negatively affected. Infested waterbodies can then act as source populations to introduce non-native vegetation to other waterbodies in the region thereby worsening the problem. The likelihood of being a source population increases if a waterbody has a high frequency of boat traffic. Many times small waterbodies that have significant amounts of boat traffic are overlooked due to the size of the waterbody. Approximately 192,050 acres of MS are covered by small waterbodies (<100 acres) which is greater than the five largest reservoirs in the state combined (117,840 acres; Ross Barnett, Sardis, Grenada, Enid, and Arkabutla reservoirs). The state has a greater number (>160,000) and density (1 per 0.51 mi<sup>2</sup>) of small waterbodies than any other state in the MidSouth (MS, AL, AR, TN, LA, and GA) region. Many waterbodies in the state that receive the highest amount of traffic are those owned and managed by the state of MS (MDWFP), federal agencies (USFWS, USFS, or USACE), or private entities. The purpose of this work was to survey small and medium sized waterbodies (100 - 7,500 acres) for the presence of invasive or problematic aquatic vegetation as no statewide survey of these waterbodies in MS has been conducted within a single growing season. In total, 42 waterbodies were surveyed between June-July 2017 and were spread throughout most major geophysical regions of Mississippi. Only four waterbodies in this survey had plant assemblages entirely composed of only native aquatic plant species while 38 (90% of surveyed waterbodies) had at least one non-native aquatic plant species. Of the 105 plant species observed, 15 were non-native (14% of surveyed plants). Alligatorweed (Alternanthera philoxeroides) and torpedograss (Pancium repens) were the most widespread non-native species in the state. Brittle naiad, wild taro (Colocasia esculenta), water hyacinth (Eichhornia crassipes), and Cuban bulrush (Oxycaryum cubense) are of concern as they have the ability to rapidly colonize any waterbody in which they are introduced. The results of this survey are useful in implementing early detection, rapid response (EDRR) management options on populations of non-native aquatic plant species in Mississippi, specifically small isolated populations, before they spread to other sites. This survey highlights the need for repeated monitoring throughout Mississippi in order to know which waterbodies are impacted by aquatic invasive plants and the severity of each infestation.
Potential Management Options for Controlling Giant Salvinia (Salvinia molesta D.S. Mitchell)
Year: Authors: Sartain B.T.
Giant salvinia is a highly invasive floating aquatic fern that is spreading across the southern United States. It is an aggressive competitor that reproduces asexually through fragmentation, allowing it to easily spread to surrounding water bodies. Giant salvinia growth is rapid and biomass can double in 36 hours under optimal conditions; allowing it to form dense mats of plant material that can completely cover a water body. Due to its rapid growth and ability to form large extensive mats, water resources have been impacted immediately after the initial infestation. Dense plant growth impedes navigation, irrigation, and recreational use of water resources, leading to not only environmental impacts, but economic impacts and public health concerns. These negative impacts have led to situations where giant salvinia needs to be intensively managed to limit its growth and spread to surrounding water bodies. Chemical, biological, physical/mechanical, and integrated control methods are all potential management options available for controlling giant salvinia. Selecting the proper management option is dependent on a number of factors including: management goals and objectives, the size of the infestation, site characteristics, the primary uses of the infested water body, available budget, and proximity to sensitive plant and animal species. This presentation provides an overview of the current management options for controlling and limiting the spread of this species.
Management Practice Impacts on Runoff and Sediment Loads in the Upper Sunflower River Watershed
Year: Authors: Bingner R.L., Momm H.G., Porter W.S., Yasarer L., ElKadiri R., Aber J.
The Mississippi River alluvial floodplain is one of the most productive agricultural regions in the United States and the Upper Sunflower River watershed is an important part of this region. Over the past decade, land-use patterns in the Upper Sunflower River watershed have shifted to include more corn and soybean cropland and less cotton. In addition, irrigation adoption has increased from approximately 26% of the watershed in 2001 to 43% in 2015. This study uses the USDA Annualized Agriculture Non-Point Source (AnnAGNPS) watershed pollution modeling technology to assess the impacts of these land-use and irrigation changes on runoff and sediment loads in the Upper Sunflower River watershed. Modeling simulations demonstrated that the increase in irrigation adoption increased runoff during the irrigation season, while conversion of cotton to corn and soybean cropland reduced average annual suspended sediment loads. These results provide a starting point for understanding watershed sensitivity to changes in crop and irrigation management practices.
Does the Sudden Influx of Broiler Production Impact Nearby Surface Water Quality?
Year: Authors: Moore M.T., Locke M.A.
The United States has the largest broiler chicken industry in the world. Arkansas (1 billion head) and Mississippi (740 million head) are two of the five top broiler producing states. Although poultry is the largest agricultural commodity for both Arkansas and Mississippi, until recently, large-scale broiler production has generally been limited to a small number of clustered counties within each state. In 2014, an industry partner invested $165 million in two northeast Arkansas counties for a significant poultry complex, and by 2017, hundreds of new chicken houses were built within the Current, Upper Black, and Lower Black River watersheds. These were areas new to the broiler chicken industry, as most broiler production had occurred in the middle and extreme northwestern parts of the states. Water quality issues of high levels of phosphorus and nitrate in the Illinois River Basin in northwestern Arkansas had raised the concern of possible surface and ground water contamination by an overwhelming number of chicken houses. In northeast Arkansas, the primary rivers within these watersheds (Current and Black) provide surface water for recreation and agricultural needs. Aquatic diversity is high, and several endangered freshwater mussel species are present in these watersheds. Because of the potential concern for water quality impairment by the sudden influx of chicken houses, a small-scale evaluation began in December 2016 on a six- acre recreation pond immediately downstream of newly constructed chicken houses. Seasonal water quality and sediment sampling are underway for basic physicochemical parameters, nutrient, and pesticide concentrations. Water quality trends will be examined and discussed, along with opportunities and suggestions on research collaborations to ensure continued agricultural commodity production is harmonized with the surrounding natural resources.
Effect of Land Management on Surface Runoff Water Quality in Beasley Lake Watershed
Year: Authors: Locke M.A., Lizotte Jr. R.E., Yasarer L., Bingner R.L., Moore M.T.
Assessing best management practices in the landscape is needed to better understand their potential to mitigate sediment and nutrient loss in runnoff. Runoff and sediment and nutrient losses in Beasley Lake Watershed were monitored from 2011 to 2017. Landscape management in monitored catchments included areas under row crops with (CropBuff) and without (Crop) edge-of field buffers and under the Conservation Reserve Program (CRP). The study demonstrated that edge-of-field vegetated buffers and conservation reserve can be integral components in an agricultural landscape to reduce topsoil loss and transport of nutrients downstream concomitantly mitigating water quality impacts on rivers and lakes. Overall, efficacy in mitigating runoff losses of soil and nutrient resources, significant within-lake processes may limit the effectiveness of land management in improving downstream water quality. Results from this study should be providing additional information to improve and sustain water quality and overall environmental quality using combined conservation practices.
Management Practices to Improve Infiltration and Decrease Nutrient
Year: Authors: Spencer D., Krutz J., Locke M., Ramirez-Avila J., Henry B., Golden B.
Furrow irrigation and sealing silt loam soils contribute to a low irrigation application efficiency in Mid-Southern, USA corn production systems. Cover crops may improve irrigation application efficiency and interest in incorporating cover crops into Mid-Southern, USA production systems has risen in recent years. Studies were established in Stoneville, MS in 2017 and 2018 to determine the effects of four cover crops on corn grain yield, irrigation application efficiency, irrigation water use efficiency, and sediment and nutrient transport. Experimental design is a randomized complete block with four replications. Treatments include a reduced till/no cover (as a control), reduced tillage with cereal rye (Secale cereal L.), reduced tillage with Austrian winter pea (Pisum sativum L.), reduced tillage with tillage radish (Raphanus sativus L.), reduced tillage with crimson clover (Trifolium incarnatum L.), and no till/no cover. Except for cereal rye and Austrian winter pea, yield was decreased from 2017 to 2018 up to 47%. No till/no cover and tillage radish decreased runoff volume from 2017 to 2018 by 24.8 and 12.3%, respectively. No till/no cover also increased furrow advance time. Sediment and nutrient transport results will also be presented.
Two-Method Prediction Divergence of Water Level for the Mississippi River Valley Allluvial Aquifer to Inform Observational Network Review
Year: Authors: Asquith W.H.
Information gaps can be detected by quantifying statistical efficacy in estimation of phenomena such as groundwater levels at unmonitored locations for the Mississippi River Valley alluvial (MRVA) aquifer located within the Mississippi Alluvial Plain (MAP), south-central United States. Multi-agency water-level networks containing wells screened in the MRVA aquifer collect data in space (horizontal and vertical dimension) and time. Groundwater levels are also influenced by a given hydrogeologic framework (aquifer geometry and properties), well construction, local and regional pumping histories, and contexts of seasonal recharge and discharge. One common stakeholder inquiry concerns identification of information gaps. To quantify information gaps, a two-method approach for water-level prediction is proposed. Two statistics of interest were spring 2018 maxima (March-May) and fall 2018 minima (September-November) based on use of water-level data collected during these same months from 2014-2018 with prediction made for 2018. Spring maxima represent maximum seasonal aquifer recovery, whereas fall minima represent maximum aquifer drawdown attributable in part to irrigation demands. Data included for this study were computed from 1,411 unique wells for which 6,304 measurements (discrete or daily mean) were available. Our focus is not on the estimation of water levels per se but on the divergence between estimates using two methods (generalized additive models [GAMs] and support vector machines [SVMs]). Spatial coordinates, land-surface altitude, MRVA aquifer bottom altitude, and year were used as predictor variables. GAMs and SVMs are powerful estimation methods in their own right, but by their radically different mathematics, perform differently as extrapolation increases when predictions are increasingly made away from hyperspace of predictor variables and not necessarily away from spatial coordinates. GAMs can have curvatures away from the global mean, but SVMs must curve back to the global mean. Throughout the MAP and aligned to the 1-kilometer National Hydrogeologic Grid (NHG), absolute differences between GAM and SVM predictions were computed. Spatial depiction of the results on the NHG are shown for the entire MAP as well as for subdivision-specific GAM and SVM computations for the Boeuf, Cache, Delta, Grande Prairie, and St. Francis subdivisions. Various local areas in the MAP can be seen with large GAM-SVM divergence, and hence these areas have potential information gaps, indicating the need for additional water-level monitoring. Stakeholders are thus provided information on which to judge allocation of future resources in monitoring of the MRVA aquifer.
Using Machine-Learning Models to Predict Concentrations of Nuisance Constituents in Groundwater of the Mississippi Embayment
Year: Authors: Knierim K., Kingsbury J., Haugh C.
Machine-learning methods were used to map groundwater quality, including specific conductance (SC), total dissolved solids (TDS), and chloride, in the Mississippi River Valley Alluvial aquifer (MRVA) and the Claiborne aquifers of the Mississippi Embayment regional aquifer system. The MRVA aquifer is used widely for irrigation and locally for public supply, and high concentrations of chloride and iron can limit groundwater use. The middle Claiborne and lower Claiborne aquifers of the Mississippi Embayment are largely confined with few water-quality concerns, but higher salinity zones occur with depth as groundwater becomes more mineralized. Explanatory variables, including surficial spatial datasets (such as soil properties and land use), groundwater-flow model output (such as groundwater flux and age), and well characteristics (such as depth to screened interval) were used in boosted-regression tree models to predict SC and chloride concentrations throughout the aquifers at depth zones used for drinking water supply. TDS concentrations (which has a secondary maximum contaminant level of 250 g/L) were modeled using the correlation between SC and TDS. Surficial explanatory variables were attributed to individual wells using a 500-meter buffer, which for confined aquifers likely does not reflect the recharge zone for groundwater to the well. However, predicted values of hold-out data (not used to train the model) were in good agreement with observed values for SC models (r<sup>2</sup> = 0.62). Important predictors included surficial variables such as land-surface elevation, landscape geomorphology, well position within the aquifer system, and land use. In particular, land-surface elevation may be a good indicator of whether the well screen was located in a confined or unconfined area of the aquifer system. Therefore, mapping groundwater quality across a confined aquifer system using surficial datasets is possible, and predicted concentrations were improved when groundwater-model variables were included as explanatory variables in machine-learning models.
Estimating Irrigation Water Use in the Mississippi Alluvial Plain, 1999-2017: Aquaculture and Irrigation Water-Use Model (AIWUM) version 1.0
Year: Authors: Wilson J., Painter J., Torak L., Kress W.
Water use is a critical and often uncertain component of quantifying the water cycle and securing reliable and sustainable water supplies. Recent water-level declines in the Mississippi Alluvial Plain, especially in the Mississippi Delta, pose a threat to water sustainability. Currently, the U.S. Geological Survey (USGS) Water Availability and Use Program Mississippi Alluvial Plain Water Availability Study is developing a hydrologic decision-support system to help manage water resources in this area, one of the most productive agricultural regions in the Nation.</br></br> To improve water-use estimates needed as input to the hydrologic decision-support system, an aquaculture and irrigation water-use model, Aquaculture and Irrigation Water-Use Model (AIWUM) 1.0, was developed and compared to other reported and estimated irrigation water-use values within the study area for 1999-2017. AIWUM 1.0 is primarily driven by annual flowmeter data provided by the Mississippi Department of Environmental Quality's Delta Voluntary Metering Program as well as historical flowmeter data from the Yazoo Mississippi Delta Joint Water Management District. The model quality incorporates remote sensing and flowmeter data and outputs monthly estimates at a fine spatial (100 meters) and temporal (monthly) resolution used directly in the Mississippi Embayment Regional Aquifer Study (MERAS) groundwater model 2.1.</br></br>Results indicate annual total irrigation water-use estimates ranged from about 3 to 9 billion gallons per day and a majority of the irrigation water use was applied to soybeans (52%), followed by aquaculture and rice (26%), other crops (10%), corn (8%), and cotton (4%). Comparisons indicate that annual total irrigation water-use estimates from AIWUM 1.0 generally were smaller than all other sources of water-use data, but within the Mississippi Delta the total annual water use is approximately equal between AIWUM 1.0 and the MERAS groundwater model 2.1.<br /><br />This and other models included in the decision-support system are developed in Python and interconnected, resulting in a dynamic, instead of the traditional static, model. This approach allows models to quickly evolve as better data are available (e.g., additional flowmeter data, improved remote sensing data), providing the current best estimates of water resources to cooperators and the public. Future planned work includes (a) determination of irrigation rates based on machine learning and geostatistical methods using daily precipitation and temperature data and regional irrigation water-use from flowmeter data, (b) improved classification of crop type and irrigated versus unirrigated lands, (c) back- and forecasting estimates from 1890-2100, and (d) establishment of a public-facing, real-time irrigation water-use model.
Mapping the Variability of Specific Conductance in Groundwater of the Mississippi River Valley Alluvial Aquifer
Year: Authors: Killian C., Bussell A., Knierim K., Kingsbury J., Wacaster S., Kress W.H.
The Mississippi River Valley alluvial (MRVA) aquifer is the uppermost aquifer underlying the Mississippi Alluvial Plain (MAP) and spans portions of eight states within the Mississippi Embayment. The MRVA aquifer supplies most of the groundwater used for irrigation throughout the MAP. Water-quality conditions in parts of the aquifer may limit the availability of groundwater for irrigation, public supply, and domestic use. To better understand and map the water resources of the MAP, the U.S. Geological Survey (USGS) designed an Airborne Electromagnetic (AEM) survey to map resistivity of hydrologic units at the regional scale. Mapping resistivity changes of hydrologic units will help identify the primary drivers that influence groundwater quality in the MRVA aquifer. To accurately interpret the AEM survey data and the changes in resistivity, the spatial and vertical distribution of groundwater specific conductance throughout the aquifer needed to be delineated. This study compared newly collected and existing historical specific conductance and chloride data from over 1,500 existing wells and cooperatively funded water-quality monitoring sites screened in the MRVA aquifer to changes in geomorphology, recharge rates, and well depth. The results from this study will support threedimensional machine-learning models of specific conductance and recharge-rate estimates as a part of characterizing the water-budget components in the MAP. Results will also help to predict aquifer salinity across the region and help to characterize areas where possible upwelling from deeper saline units may impact the availability of fresh water in shallower aquifers.
Projection of Climate Change Impact on Groundwater Resources in the Upper Yazoo River Watershed, Mississippi
Year: Authors: Ouyang Y., Jin W., Feng G., Yang J.
Groundwater depletion due to anthropogenic activities is an issue of water resource concern worldwide, while climate change adds the uncertainties to this concern. Currently, very few efforts have been devoted to projecting the impact of climate change on groundwater resources in forest and crop lands in Mississippi, which is crucial to water resource managers and farmers in the region. In this study, we modify the USGS's MERAS (Mississippi Embayment Regional Aquifer Study) model to assess the impact of potential climate change on groundwater flow and level in the Upper Yazoo River watershed (UYRW), Mississippi. This watershed consists of two major land uses: one is the forest land and the other is the crop land. Three simulation scenarios were developed in this study. Scenario 1 is a base scenario with the input parameter values similar to those of MERAS model. Scenarios 2 and 3 are the same as Scenario 1 except that Scenario 2 increased while Scenario 3 decreased the groundwater recharge rates by 1 and 2%. The latter two scenarios were developed based on our observations of the past 100 plus years' rainfall trends. In general, the impact of climate change on groundwater flow in the UYRW was primarily through its impact on groundwater recharges due to the changes in rainfall events. Simulation results showed that a 2% increase in groundwater recharge rate increased average groundwater head by 0.39 ft after 21 years, whereas a 2% decrease in groundwater recharge rate decreased groundwater head by 0.36 ft after 21 years. Furthermore, a 2% increase in groundwater recharge rate increased groundwater volume by 201,401 ft<sup>3</sup>/y after 21 years, while a 2% decrease in groundwater recharge rate decreased groundwater volume by 185,909 ft<sup>3</sup>/y after 21 years. Impacts of climate change through its impacts on groundwater recharge due to rainfall change were discernable. Further study is therefore warranted to apply the same approach to estimate impacts of climate change on groundwater resources for the entire Mississippi Embayment Regional Aquifer by combing the MERAS and HSPF models using the Integrated Hydrologic Model.
An Exploratory Study of Introducing Common Property-Based Management for the Sustainable Groundwater use in Mississippi
Year: Authors: Ko J.
Underground water levels have dropped in Mississippi over the last two decades, because most municipalities have depended on groundwater for their tap water sources and irrigations for large-scale cash crop - cotton, corn, soybean farming also have depended on groundwater in the State of Mississippi. The natural resource is regarded as private property and reporting of water use is not required in state. Currently the voluntary reporting of groundwater withdrawal has remained at ten percent and the State of Mississippi is in a legal dispute with Tennessee over the groundwater near the state border to secure more groundwater. These cases show well serious challenges in designing programs for stabilizing water table in aquafer, and for sustainable water use in the State. Elinor Ostrom (co-recipient of the Nobel prize in economics in 2009) and her associates have developed theoretical and empirical studies of common property-based management for natural resources, including aquafer. Western States, which had adopted private property as fundamental right in their state water policies, have increasingly adopted the common property-based management in managing their watersheds and aquafers over the years. For example, Arizona designates the areas experiencing rapidly depleting groundwater as Active Management Areas and mandates estimation of safe-yield and preservation of groundwater for future use. The proposed study examines differences between private property-based and common property-based managements and explores potential changes in Mississippi from the cases of water management in the Western States, if adopted.
DNF Shallow Ground Water Monitoring Wells
Year: Authors: Johnson D.R.
In 2010 the USACE established 25 groundwater monitoring wells in Delta National Forest and Twin Oaks Wildlife Management Area. Each well extends approximately three feet into the ground. The intent was to determine the depth and duration of soil saturation in a bottomland hardwood forest. The hydrology component of wetlands can be satisfied by the saturation of the top foot of soil during a continuous 21 day period during the growing season. Well locations were sited based on historical stage and duration data. Wells were placed in locations that had a flood frequency from 1 year to 50 year intervals, and an annual continuous duration from one to 28 days. The observed periods of soil saturation differed significantly from the flood duration, and ranged from zero to 250 days per year. Most sites were saturated for more than 50 days per year. This study shows that these wetlands are classic BLH wetlands, where the major source of moisture comes from winter rains. The infrequent out of bank flooding augments the available moisture.
Hydrogeologic Thresholds Affect Groundwater-Surface Water Interactions of the Big Sunflower River at Sunflower, Mississippi
Year: Authors: O'Reilly A.M., Holt R.M., Davidson G.R., Patton A., Rigby J.R., Barlow J.
At a site near Sunflower, Mississippi, observations of Big Sunflower River stage and adjacent groundwater level indicate a disproportionately larger response in groundwater level above a certain stage elevation. This suggests the river contributes water to the aquifer at a higher rate above a threshold that defines high-stage versus lower-stage periods. This is in contrast with the common assumption of a linear relation between river leakage and water-level difference between the river and aquifer. Heterogeneity in the riverbed or near-field geology can impart such a threshold effect on groundwater-surface water (GW-SW) exchange. Variations in the texture of riverbed sediments and lithologic variations in underlying geology are examples of common heterogeneities. Hydrologic interaction with these heterogeneities leads to distinct types of behavior that switch when river stage or groundwater level rises above or falls below the interface.</br></br> A simple dynamic water-balance (linear reservoir) model was developed to investigate this phenomenon at the study site on the Big Sunflower River. Four conceptual models, each of which consists of a perched aquifer that receives recharge from the riverbank and loses water to the underlying Mississippi River Valley alluvial aquifer, were tested: homogenous riverbank and aquifer lithology, two-layer riverbank and homogenous aquifer lithology, two-layer riverbank and two-layer aquifer lithology, and homogenous riverbank and two-layer aquifer lithology. Models were run using hourly observed river stage, calibrated to a 382-day period of water-level measurements in a nearby well, and rerun for the entire 1,278-day period of record. All models matched observed groundwater levels reasonably well, with a maximum root-mean-square error (RMSE) of 0.46 m. However, the heterogeneous models matched high-stage events substantially better than the homogeneous model, with the best performance (RMSE of 0.27 m) by the model incorporating threshold effects controlled by both two-layer riverbank and two-layer aquifer lithology. Substantial flow occurs through both the upper riverbank, representing about 30% of the flow through the lower riverbank, and the upper aquifer, representing about 25% of flow through the lower aquifer.</br></br> These results illustrate the importance of considering threshold effects on GW-SW interactions. Regional-scale, numerical, groundwater models typically do not incorporate threshold effects, because the causative heterogeneities exist at a scale smaller than a single grid cell. Models such as those developed here can be incorporated into numerical groundwater models to better simulate intra-cell processes that cannot be effectively modeled at the regional scale.
Linking Agricultural Best Management Practices with Eutrophication and Oxygen Stress
Year: Authors: Lizotte R.E., Yasarer L., Locke M.A.
Intensive row-crop agriculture in the Mississippi Delta have well-documented impacts on lakes in the region. Eutrophication resulting from nutrient loads (nitrogen and phosphorus) in runoff directly affect lake productivity and dissolved oxygen. Agricultural best management practices (BMPs) supported by the USDA Natural Resources Conservation Service (NRCS) can be implemented by land users to help protect and improve water quality. Although NRCS supported BMPs are primarily used to control soil loss, erosion and associated sediment loads in runoff, these same practices have the added benefit of reducing nutrient loads. The current study attempts to assess the effects of BMPs on lake eutrophication and associated oxygen stress in two Mississippi Delta lake watersheds. Beasley Lake watershed (BL) in Sunflower County has multiple integrated BMPs (16.9% watershed acreage) including edge-of-field vegetated buffers, conservation reserve areas and constructed wetland habitats. In contrast, Roundaway Lake watershed in Coahoma County has a few isolated BMPs (2.3% watershed acreage) including conservation reserve areas and a constructed wetland habitat. During May-September 2018, biweekly water quality variables comprising soluble orthophosphate (PO<sub>4</sub>-P), total phosphorus (TP), nitrate nitrogen (NO<sub>3</sub>-N), total Kjeldahl nitrogen (TKN), chlorophyll a (total algal biomass), phycocyanin (cyanobacteria biomass), and weekly diel surface dissolved oxygen (DO, 0.3 m at 15 minute intervals) were measured. Nutrient data showed BL had significantly lower concentrations of TKN (p < 0.001) and TP (p = 0.003) than RL. Mean summer TKN in BL and RL were 1.098 and 1.581 mg/L, respectively, and mean summer TP in BL and RL were 0.079 and 0.147 mg/L, respectively. However, mean summer NO<sub>3</sub>-N (p = 0.416) and PO<sub>4</sub>-P (p = 0.836) concentrations were not significantly different between BL (0.024 mg NO<sub>3</sub>-N/L and 0.021 mg PO<sub>4</sub>-P/L) and RL (0.061 mg NO<sub>3</sub>-N/L and 0.023 mg PO<sub>4</sub>-P/L). Mean summer total algal biomass (36-58 g/L) and cyanobacteria biomass (30-102 g/L) were both significantly lower in BL relative to RL (p < 0.010). Concomitantly, frequency of summer DO stress (as DO < 4 mg/L in hours per week) was significantly lower (p = 0.010) in BL (3.4 hours per week) than RL (37.6 hours per week). Correlation and regression analyses indicated associations with increased BMPs, decreased total nutrient inputs, corresponding decreased algal biomass, and decreased DO stress during summer of 2018. Results clearly indicated BL, in the presence of more intensive BMPs, was significantly less eutrophic and less oxygen stressed than RL during summer conditions.
Characterizing Legacy Phosphorus Storage and Release from Beasley Lake Sediments
Year: Authors: Yasarer L., Martin H., Locke M.A., Taylor J., Lizotte Jr. R.E., Stevens E.
Agricultural soils in the Mississippi Delta are notoriously rich in legacy phosphorus. Due to high erosion rates, nutrient-rich soil often ends up in Delta lakes and water bodies. However, few studies have been conducted to quantify the phosphorus stored in these sediments and to estimate potential fluxes in lake environments. This study represents a starting point for characterizing legacy phosphorus in aquatic environments in the Delta utilizing sediment and data collected from Beasley Lake, an oxbow lake in an agricultural watershed that has been studied by the USDA-ARS since 1995. Twelve sediment cores were collected from two locations: six from the littoral zone (depth = 1.5 m) and six from the limnetic zone (depth = 2.8 m). Cores were incubated for two weeks with either aerobic or anaerobic treatments. Sediment samples were also taken from each lake coring site and chemical and physical characterization, sequential phosphorus extractions, and phosphorus isotherm analyses were performed. Results from the experimental incubated cores demonstrated average phosphorus fluxes of 0.77 and 1.72 mg/m<sup>2</sup>/day under aerobic conditions and 15.26 and 22.33 mg/m<sup>2</sup>/day under anaerobic conditions from the littoral and limnetic zones, respectively. Results from the sediment characterization demonstrated that Beasley Lake sediments are indeed storing a large amount of phosphorus (P), up to 279 g-P per g dry sediment. Yet, results of the isotherm analysis suggest the sediments have the potential to adsorb up to 3200 g-P per g dry sediment under oxygenated conditions. These results suggest that Beasley Lake has a large pool of available phosphorus, but still has the potential to store more under oxygenated conditions. With anaerobic conditions this phosphorus may be released into the water column where it could stimulate algal growth. Dissolved oxygen (DO) conditions near the sediment interface in Beasley Lake have been measured since May 2018 and will be continuously measured to understand seasonal DO patterns. The combination of experimental analysis of phosphorus release and field observation of lake conditions will help provide a deeper understanding of aquatic nutrient cycling in Beasley Lake and potentially other Delta water bodies.
Demystifying Denitrification in Mississippi Delta Lakes
Year: Authors: Taylor J.M., Lizotte R., Ochs C.
Denitrification (DNF) is a biologically-mediated mechanism that converts nitrate (NO<sub>3</sub>-N) to di-nitrogen (N<sub>2</sub>) gas and potentially removes excess N from intervening waterbodies distributed across the Mississippi Delta landscape. Despite its considerable influence on N cycling and potential mitigation potential as an ecosystem process, very little information is available on denitrification rates in Delta water bodies. We use two different approaches to measure DNF with data collected from two different Delta habitat types: a bayou within the Delta interior (Roundaway Lake), and historic river meander cutoff of the lower Mississippi River (Desoto Lake). Results indicate that significant DNF occurs within Delta lake habitats and rates are governed by organic matter and N availability. Sediment core incubations from Roundaway Lake indicate DNF rates increase with increasing N availability and were enhanced by crop organic matter transported from adjacent agricultural fields. Connectivity with the Mississippi River during spring flooding resulted in high N enrichment in Desoto Lake. After the river receded and separated from the lake, NO<sub>3</sub>-N concentration decreased with corresponding increases in N<sub>2</sub> gas concentrations in the hypolimnion, indicating that denitrification can play a significant role in N removal within off channel habitats of the river. Information on factors that influence DNF in Delta waterbodies can improve models of N cycling and export within Delta watersheds as well as identify potential management strategies for enhancing DNF and N mitigation within the region.
Seasonal Sediment Accumulation Rates in Beasley Lake, MS
Year: Authors: Wren D.G., Taylor J.M., Rigby J.R., Locke M.A., Yasarer L.
Recent sedimentation rates are useful for quantifying the effects of changing watershed conditions on soil erosion; however, typical geochronological methods for dating sediments are limited in temporal resolution. We used sediment traps to measure short-term sediment accumulation rates in Beasley Lake, Mississippi, a natural oxbow lake whose watershed has a mix of agricultural and forested land. Precipitation data from a local Soil Climate Analysis Network (SCAN) site and water quality measurements from Beasley Lake were used to explain patterns in sediment deposition rates. We found that sediment accumulation in the traps was highest in the summer, while the highest rate of runoff occurred in late winter and early spring. The delay between fine sediments entering the lake and deposition in the traps prevented the detection of changes in watershed erosion within seasons; however, sediment traps were shown to be useful for inferring changes in watershed erosion rates on annual timescales. Our findings contribute new understanding of the interactions between suspended sediments, algal biomass, and water chemistry in a natural oxbow lake and provide support for using sediment traps to measure intra-annual variability in sedimentation rates in oxbow lakes
Putting Flow-Ecology Relationships into Practice: A Decision-Support System to Assess Fish Community Response to Water-Management Scenarios
Year: Authors: Nebiker S., Caldwell C., Knight R.
Understanding the relationship between the ecological health of a stream and its flow is critical for resource managers to develop effective water management plans that address multiple and often conflicting uses throughout a river basin. Since management objectives must be considered in a basin-wide context, it is important to conduct regional analyses of the relationship between streamflow and riverine ecosystems that account for differences in physiography, land use, and topography. Further, for the flow-ecology recommendations to be scientifically credible, they must be derived from measured data. However, the effort required to do these analyses on a regional scale, let alone on an individual river segment, can be prohibitive.</br></br> Throughout the eco-flow assessment process, decision makers must be involved so as to promote collaboration between stakeholders and to identify the trade-offs between varying management strategies. To that end, it is helpful to (a) distill the underlying analysis down to the most ecologically-relevant flow criteria so that flow-management models can quickly generate results and (b) distill the resulting environmental metrics down to an easily understood concept like fish diversity, i.e., number of fish species. For decades, the integration described above has been elusive. This presentation introduces a framework to operationalize flow-ecology relationships into decision-support systems of practical use to water-resource managers, who are commonly tasked with balancing multiple competing socioeconomic and environmental priorities. We illustrate this framework using a case study from the Tennessee River Basin - one of the most ecologically diverse basins in the United States - whereby fish community responses to various water-management scenarios were predicted in a partially-regulated river system at a local watershed scale. The water-allocation modeling framework used - OASIS - is flexible, transparent, and allows for quick screening of management scenarios which positions it to be used in a collaborative setting with watershed stakeholders.
Freshwater Delivery to the Gulf of Mexico: an analysis of streamflow trends in the Southeast US from 1950 - 2015
Year: Authors: Rodgers K.D., Roland V.L., Hoos A.B., Knight R.R.
The U.S. Geological Survey and U.S. EPA are collaborating to assess the climatic, physiographic, and anthropogenic factors driving spatial variability and temporal trends in the freshwater delivery to the Gulf of Mexico. The timing and magnitude of fresh water delivery influences terrestrial and aquatic communities, changing community composition and altering habitats necessary to support indigenous life. Streamflow at 139 stream gaging stations in the southeastern United States were analyzed from 1950 to 2015 to determine if climatic oscillation, spatial correlation, and variability in the streamflow indicated significant increases or decrease for the period of record. This study examined spatial and temporal patterns in seasonal and monthly mean daily streamflow and for quantiles of streamflow. Three primary methods were used to analyze streamflow trends including: 1) the non-parametric Mann-Kendall trends test to identify monotonic change, 2) cluster analysis to determine if trends in streamflow were regional in nature, and 3) Quantile-Kendall analysis to identify trends over the period of record. Results from our analysis have identified significant trends in monthly and seasonal streamflow values as well as significant trends over the entire flow regime.
An Interactive Data Visualization Tool for Exploring the Causes and Extent of Streamflow Alteration across the Lower Mississippi and Gulf Coast Region
Year: Authors: Walker J.D., Knight R., Letcher B.
The U.S. Geological Survey Lower Mississippi-Gulf Water Science Center and the U.S. Environmental Protection Agency are performing a comprehensive assessment of streams that flow into the Gulf of Mexico. The goal of this assessment is to assist resource managers in identifying and prioritizing opportunities for flow restoration and thereby protect and replenish valuable coastal water resources. This assessment will generate numerous large and complex datasets including geospatial basin characteristics and streamflow statistics that reflect the magnitude, timing, trend, and degree of alteration for freshwater delivery to the Gulf. To make these datasets accessible to decision makers and other researchers, we developed a web-based data visualization tool called the Interactive Catchment Explorer for the Lower Mississippi Gulf (ICE-LMG).</br></br> ICE-LMG was built using the ICE framework, which is a generalized web application platform developed as part of the Spatial Hydro-Ecological Decision System (SHEDS) and is designed for exploring large environmental datasets and model outputs. ICE utilizes modern web technologies and numerous free and open source software (FOSS) libraries to provide an engaging user experience through a high degree of interactivity and responsiveness. The ICE framework has been applied to projects across the country including stream temperature and trout occupancy model predictions for the Northeast and Mid-Atlantic U.S. and a climate vulnerability assessment of endangered fish species in the northern Rocky Mountains.</br></br> The ICE-LMG web application will provide a map-based interface for viewing spatial patterns of basin characteristics, streamflow statistics, and various metrics of flow alteration across the Gulf Coast region. The base map will be coupled to interactive histograms that show the distributions of selected variables and can be used to filter the dataset by applying single- or multi-variate criteria through a technique called cross filtering. Using this technique, users can interactively explore spatial and temporal patterns of each variable, as well as understand the correlations between the variables.</br></br> This presentation will describe the motivation and approach to developing the general ICE framework and its application to the Lower Mississippi-Gulf region. We will then demonstrate how ICE-LMG can be used to explore datasets and develop a better understanding of the causes and extents of streamflow alteration across this region. By making the results of this study available to local and state decision makers through an engaging user interface, it is our hope that ICE-LMG will serve as a valuable decision support tool for facilitating flow restoration efforts and stimulating further research.
Seasonal and Annual Salinity Trends in the Mississippi Sound in Response to Extreme Weather and Freshwater Inflow, 1995-2018
Year: Authors: Swarzenski C.M., Rodgers K.D., Mize S.V.
The U.S. Geological Survey and U.S. Environmental Protection Agency have begun a preliminary assessment of seasonal and annual salinity trends in the Mississippi Sound, an area that extends from Mobile Bay in Alabama to Bayou Rigolettes in Louisiana. On the south, the Sound is separated from the Gulf of Mexico by a series of barrier islands. These islands allow the exchange of water between the Gulf and Mississippi Sound through a series of tidal passes. The Pascagoula and Pearl Rivers along with a few smaller rivers locally introduce the majority of freshwater into the Sound. Freshwater may also enter the Sound through Lake Pontchartrain during openings of the Bonnet Carre spillway. Extreme weather events such as tropical storms and heavy rainfall further influence salinity.</br></br> Annual and seasonal trends in salinity and freshwater inflow from local watersheds are being evaluated using Kendall-Tau analysis. Stations from Mobile Bay, the Mississippi Sound and the nearshore waters of eastern coastal Louisiana are included. Not surprisingly, salinity in the Mississippi Sound, and by extension, water-quality are controlled by the timing and quantity of freshwater input and the rate of lateral exchange of water along the coasts of Alabama, Louisiana, and Mississippi. Salinity is a determining factor for productivity in estuarine waters and understanding the factors that control salinity variability are fundamental to understand biological functioning and health, as well as, source water partitioning in the Mississippi Sound.
Case Studies of Rapid Dam Breach Modeling during Flood Events
Year: Authors: Crosby W.
The USACE Modeling Mapping and Consequences Production Center (MMC) provides hydraulic modeling, mapping and consequence analysis for USACE dams in support of the USACE Dam Safety and Critical Infrastructure Protection and Resilience (CIPR) Programs. The MMC has developed processes, tools and standards for creating dam breach hydraulic models for use in emergency action plans (EAP), during real-time flood events, and in support of the Corps Dam Safety and Security programs. The MMC-developed standards have been used to provide dam failure modeling for over 500 USACE dams and multiple flood events, involving over 1000's of stream miles throughout the continental U.S. and Alaska. The MMC also provides Flood Inundation Modeling support during real-time flood events with its Flood Inundation Modeling Cadre (FIM). The mission of the FIM Cadre is to assist districts when called upon to run real-time hydraulic models, prepare forecast inundation maps, and develop consequence estimates for significant flood events. Since supporting the flooding efforts during the 2011 flood of record on the Mississippi River and the 2011 flood on the Missouri River, the FIM Cadre has been called in to support multiple flood events across the nation, including support during some hurricanes.</br></br> This presentation will provide case studies where the MMC FIM Cadre has supported flood inundation modeling during flood events. The presentation will primarily focus on dam break analysis during hurricanes. In 2015 the MMC performed a dam break analysis in South Carolina during Hurricane Joaquin. Additionally, MMC performed 2 dam break analysis during Hurricane Matthew in 2016. The MMC FIM Cadre has also performed numerous levee breach analysis during flood events.
Theory-Guided Data-Driven Modeling of Groundwater Levels in an Alluvial Aquifer
Year: Authors: Abrokwah K., O'Reilly A.M.
Groundwater is an important resource that is extracted every day because of its invaluable use for domestic, industrial, and agricultural purposes. The need for sustaining groundwater resources is clearly indicated by declining water levels and has led to increasing demand for modeling and forecasting accurate groundwater levels. In this research, results of wavelet analysis-artificial neural network (WA-ANN) data-driven models for simulating groundwater levels are compared to the results of aquifer water levels simulated using physics-based MODFLOW models. That is, we compare the results of each model to understand how WA-ANN model results relate to real physical hydrogeologic properties, e.g. hydraulic conductivity (K) and specific storage (Ss), with the objective of using physical principles (theory) to guide development of data-driven models. These techniques are explored by modeling groundwater levels in a synthetic alluvial aquifer system consisting of a river and an unconfined aquifer, two confined aquifers, and confining layers separating each aquifer. A synthetic time series representing daily values of recharge to the unconfined aquifer, with seasonal and shorter time-scale periodicity, is used as the forcing function. Properties of K and Ss for aquifers and confining layers as well as river properties are assigned assumed values in the MODFLOW model. Simulated water levels from MODFLOW at an observation well in each aquifer are then modeled again with a WA-ANN model for each well by using various decomposition levels of the discrete wavelet transform (DWT). The DWT is used to decompose the recharge time-series data into various levels of approximate and details wavelet coefficients, which are then used as inputs for the WA-ANN models. The results for the various DWT decomposition levels of the WA-ANN models are then compared to the simulated water levels and hydrogeologic property values of the MODFLOW model. Based on this comparison, potential relationships are identified between the characteristics of the various decomposed wavelet levels of the WA-ANN models and the hydrogeologic properties of the MODFLOW model. The resulting knowledge of the underlying physics manifest by the WA-ANN models, inferred by comparison with a physics-based model, ultimately produces theory-guided data-driven models, imparting science-based consistency and interpretability into data science models.
Numerical Studies of Ground Water Flow near a Partially Penetrated Well and an Alluvial River
Year: Authors: Fang J., Jia Y., Ozeren Y., Rigby J.R.
The Mississippi Delta is a productive agricultural area in the United States, the agriculture, however, heavily relies on groundwater. In the last decades, the ground water table has experienced a significant drawdown. The current way of using groundwater is not sustainable. This problem has drawn attention of water resource management agencies and research community.</br></br> In this study, a newly developed 3D groundwater model, CCHE3D-GW, was used to analyze this problem. The model is verified using analytical solutions including a stream depletion case considering the effects of both pumping and surface water charging from a stream (Butler et al. 2001). Several scenarios with different ratios between the conductivity of streambed and aquifer were simulated. The agreements between the simulation results and the analytical solutions verified the model.</br></br> The model was then applied to the pumping tests of a USDA project in Money, Mississippi. The pumping site is very close to the Tallahatchie River and the relations between the pumping and the surface water charging is studied. The complex conditions of the aquifers, river morphology, and sediment bed have been incorporated in the numerical model and preliminary simulation results have been obtained. Additional study is in progress. The results will be reported in the conference.
Estimation of a Probable Maximum Precipitation and Probable Maximum Flood with associated Frequency: Blakely Mountain Dam
Year: Authors: Moree D.
Blakely Mountain Dam controls flow on a 1,105 square mile watershed and is located upstream of Hot Springs, Arkansas. In order to better understand the hydrologic risks associated with the dam, the following items are being performed to increase confidence in the probable maximum flood for Blakely Mountain Dam and its assigned frequency. An outline of the methodology used to complete each process will be presented, with a focus on the creation of probable maximum precipitation dataset and the routing of the event to the dam.</br> <ul><li> Preform a Site-Specific Probable Maximum Flood Analysis and compare with the standard HMR 51/52 Methodology. Use Sensitivity analyses to determine upper, lower, and best estimate.</li> <li> Create hydrologic model (HEC-HMS) with adequate calibration and validation. Calculate peaking factors to account for added runoff volume</li> <li> Complete a survey of dam and spillway crest. Use 2-dimensional modeling to validate rating curves for spillway and am overtopping.</li> <li> Create a reservoir routing model (HEC-ResSim) with the ability to model downstream flow constraints. Validate the mod</li> <li> Perform a paleoflood analysis to extend the effective record length of the reservoir inflow data, and increase confidence in estimates of extreme flood probability</li> <li>Gather historical flood records dating back to 1800's and incorporate the historical records and the paleoflood information into the inflow volume-frequency curve using HEC-SSP.</li> <li>Compare the inflow volume-frequency curve to the regional precipitation-frequency curve from NOAA Atlas 14 to see if the estimated return periods for the PMP and PMF are consistent.</li> <li>Update the stage-frequency curve using a Reservoir Frequency Analysis Tool (RMC-RFA) with the new volume-frequency curve.</li> <li>Use the stage-frequency curve to assign a reoccurrence frequency values to Spillway, Top of Dam and PMF elevations.</li><ul>
Alabama Groundwater Monitoring Using NGWMN
Year: Authors: Arnold A.C.
Using the USGS National Groundwater Monitoring Network (NGWMN) framework document, Geological Survey of Alabama (GSA) staff are currently evaluating observation wells throughout the State to place them into subnetworks of background, suspected or documented changes in water-level elevations. The NGWMN's primary mission is to provide a national online map/data interface to address regional groundwater questions focused on principal aquifers. The GSA staff measure static water levels in observation wells bi-annually. These April and October measurements represent seasonal variation of wet and dry conditions. Many GSA observation wells have recorded water-level elevations for over forty years. The overall approach is to define areas with clusters of high-volume pumping wells. Groundwater use data supplied by the Alabama Office of Water Resources (OWR) provides locations for wells extracting >100,000 gallons per day, chiefly for municipal, agricultural and industrial uses. Within areas of significant groundwater use, GSA will evaluate the observation well network for potential aquifer drawdown. Five areas have tentatively been identified as background that are not affected by intensive groundwater withdrawal. Background areas are situated in low-yielding aquifers of the Cumberland Plateau or Piedmont region, with few major supply wells. The primary areas being evaluated for suspected changes due to groundwater withdrawal are Gulf Coastal Plain, Valley and Ridge, and Highland Rim aquifers. No areas have been classified as documented changes. Future studies will include analyses of available pump test data and delineation of water-level trends in major Alabama aquifers within these areas.
Exploitation of UAS to Analyze River Flooding
Year: Authors: Moorhead R., Dyer J., van Cooten S.
Unmanned aircraft systems (UASs) have been shown to be cost-effective and efficient data collection platforms for high-resolution and/or real-time imagery. NOAA's River Forecast Centers (RFCs) have stated that some of their top priorities for UAS applications for RFC operations are rapid response images to document extent of inundation to verify flash flooding, flood inundation maps, and enabling production of flood maps for more locations. The lack of data over river reaches that are difficult to access and/or a large distance from population centers degrades overall river forecast accuracy. This is especially true if the river reaches with poor elevation data are known to exhibit complex hydraulic conditions such as backwater flow during high water events. In such cases, not only do real time data and images provide improved accuracy in river flow speed and direction, but also aid in quantifying the amount of potential storage along the river reach during flood events.</br></br> Such backwater processes are known to occur along the Yazoo River in western Mississippi, which is in the operational area of the Lower Mississippi River Forecast Center (LMRFC). More specifically, the backwater areas of interest in this study are along the Yazoo River and the contributing tributaries of the Big Black and Sunflower River. The LMRFC forecasts for this area are based on river gauges near Belzoni and Yazoo City along the Yazoo River, near Bovina and Bentonia along the Big Black River, and near Anguilla and Sunflower along the Sunflower River. These points all lie in areas with minimal changes in relief. This area is of great interest and concern to NOAA, USGS, and USDA due to the frequency and severity of flooding and the associated major economic and societal impacts.</br></br> This presentation will cover our work on establishing CONOPS, the data collected, and preliminary assessments of the value of the UAS-collected data in river forecasting. The initial phase of the study is being conducted in the area around the Greenwood, Mississippi airport.
Planning to Integrate Small Unmanned Aerial Systems (sUAS) into Your Current Data Acquisition Workflow? The State of the Technology: Highlights, Case
Year: Authors: Yarbrough L.D.
They are in the news. You see them in the workplace as well as with recreational hobbyists. They have been the cause of occasional airport closures. I will present an overview of the current state of the technology and discuss examples from current and past projects to explore the many uses of small unmanned aerial system (sUAS), commonly called drones. From the perspective of remote sensing and aerial imaging, the recent explosion of the sUAS has a long, well-established foundation dating back to the mid-1800s when wet glass daguerreotypes were set aloft with balloons and kites. Mississippi, too, has had a long history of developing sUAS technology in research, teaching and application. Key aspects of mission planning, flight operations, safety protocols, data curation, data analysis and product development are all interdependent and are developed from the needs of the end-user or client. I will discuss the regulatory environment and flight restrictions that may affect your choice of sensor, payload needs, and size of sUAS. From commercially-available, to a custom bird and ever-increasing selection of sensor payloads, the future trend quite literally has the sky as the limit.
Project Efficiency: Advantages of UAS Technology in Civil and Environmental Engineering
Year: Authors: Lawson J., Parrish J.
The use of unmanned aircraft systems (UAS) in civilian and non-military sectors has skyrocketed over the past several years with predictions of exponential demand for UAS and related services in the coming years. In this era of disruptive innovation, rapid advances in UAS technology along with implementation of the FAA's 2016 UAS guidelines have boosted the economic development landscape on multiple levels. More UAS and associated features are being produced by manufacturers than ever before, and remote pilot certifications are on the rise. Utilization of UAS technology in the environmental and engineering fields has gained momentum as the capabilities of UAS applications are becoming abundant and more site-specific.</br></br> What was once seen as too great of a risk to undertake is now considered a valuable investment by environmental and engineering firms. Professionals are increasingly employing certified remote pilots and creating their own UAS divisions. Improved data collection rates and accuracy, lower number of safety risks and costs, and numerous compatible data processing platforms are marked advantages that current UAS technologies allow. Further, UAS software is compatible with global positioning systems and can be manipulated to form 3D models and a surfeit of other outputs. These factors are just a few of the reasons UAS technology is preferred over traditional labor-intensive methods.</br></br> The versatility of UAS operations over water and unsafe, rugged terrain is ideal for enhancing and accelerating projects such as inspecting inlet and outfall structures at wastewater treatment facilities and detecting leachate leaks at solid waste facilities. A few other examples of areas benefitting from UAS technology include dam spillway condition assessments, erosion monitoring, and natural disaster evaluations involving flooding events. From the water resources standpoint, opportunities are boundless for how UAS technology has and will continue to benefit the environmental and engineering fields.
Evaluating the Use of sUAS-Derived Imagery for Monitoring Flood Protection Infrastructure
Year: Authors: Dietz E., Yarbrough L.D.
In the U.S. there are approximately 33,000 miles of levee. This includes 14,500 miles of levee systems associated with U.S. Army Corps of Engineers programs and approximately 15,000 miles from other states and federal agencies. More than 14 million people live behind levees and associated flood prevention infrastructure. Monitoring and risk assessment are an on-going process, especially during times of flood conditions. The historic events such as those in the City of New Orleans with Hurricane Katrina in 2005, Red River floods of 2009 and 2011, Ohio River flooding of 2018, the 2017 California Floods have profoundly impacted lives and communities. Climate change and increasing population are likely to make flooding events more frequent and costly. As new technologies emerge monitoring and risk assessment can benefit to increase community resiliency. </br></br> In this research, we investigate the use of the structure from motion photogrammetric method to monitor positional changes in invariant objects such as levees, specifically, I-walls. This method uses conventional digital images from multiple view locations and angles by either a moving aerial platform or terrestrial photography. Using parallel coded software and accompanying hardware, 3D point clouds, digital surface models, and orthophotos can be created. By providing comparisons of similar processing workflows with a variety of imaging acquisition criteria using commercially available unmanned aerial systems (UAS), we created image sets multiple times of a simulated I-wall at various flight elevations, look angles, and image density (e.g. effective overlap). The comparisons can be used for sensor selection and mission planning to improve the quality of the final product. The results can optimize current equipment capabilities with respect to client expectations and current FAA limitations.
Mobile Water/Wastewater Treatment Systems Developed by the Army Engineer Research and Development Center
Year: Authors: Medina V.F., Griggs C., Waisner S.
The U.S. Army Engineer Research & Development Center has developed and studied a variety of mobile water and wastewater treatment systems to address the needs of the military. These technologies also have applications for civilian purposes, such as providing for small rural communities, treatment of contamination and industrial wastewater, and disaster response. This project will discuss four projects, and will explore how these can be adapted for civilian use.</br></br> The first project was the development of the Deployable Aerobic Aqueous Bioreactor (DAAB), a mobile wastewater treatment system developed to support military operations. The DAAB is a membrane bioreactor that is designed to start up quickly thanks to special cultures of microorganisms designed to seed the reactor. It is a unique modular design that allows the system to be easily upgraded in increments of 250 men.</br></br> The second project was the exploration of anaerobic digestion to treat both food and black water generated at base camps during military operations. Base camps typically generate large amounts of food waste, which can be very difficult to manage. Our study showed that anaerobic digestion can treat food wastes along with toilet waste, and generate useful energy, up to 30% of the needs of the base camp. This could result in fewer resupply missions, saving money and lives.</br></br> The third project is a grey water (shower, laundry, and food waste wastewater) treatment project that is currently in progress. This process uses a novel, low energy reverse osmosis process coupled with a membrane bioreactor to treat grey water to allow total reuse of the water in an energy efficient manner. Testing at Camp Shelby in Mississippi is currently in progress.</br></br> The last project is the development of the Decontamination Effluent Treatment System (DETS), which is the first ever system designed to treat decontamination water. The DETS is designed to treat highly contaminated water that may contain very toxic constituents and achieve effective treatment every time. And, it is fully mobile. The DETS proved to be so effective that new uses are now being explored, including for the treatment of perfluorinated compounds, fracking fluids, and for disaster response.
Distributions of Dissolved Trace Elements in Mississippi Coastal Waters: Influence of Hypoxia, Submarine Groundwater, and Episodic Events
Year: Authors: Ho P., Shiller A.
A multi-year (2007-2011) chemical time series of eight stations in the western Mississippi Sound and northwestern Mississippi Bight was undertaken to examine the factors affecting the distributions of trace elements in this estuarine-coastal system. Key findings include the frequent development of bottom water hypoxia in this part of the Bight during late spring and summer, the likely contribution of submarine groundwater discharge (SGD) to the material flows (i.e., Ba, V and nutrients), and the effects of episodic events (i.e., tropical storms, cold fronts, the opening of the Bonnet Carr Spillway) on trace element distributions. A variety of trace metals (i.e., Ba, Mn, V and Cs) in Mississippi Sound surface waters were largely regulated by the temporal and spatial variations of riverine sources. For instance, in fall and winter, high concentrations of dissolved Mn at the most nearshore stations followed by a sharp decline in concentrations offshore, are indicative of Pearl River influence in the Mississippi Sound. Cs-rich water coming from St. Louis Bay is evident in the Mississippi Sound, but not observable in Mississippi Bight.</br></br> In hypoxic bottom waters, enriched Mn and Ba as well as depleted V were commonly observed. Consideration of the mass balances of dissolved Ba and V suggests that SGD can be a significant contributor to the chemical mass balance in this region, not just for certain trace elements, but for nutrients, too. Interestingly, a seasonal change in the direction of the V flux from the sediments suggests that the chemical conditions (i.e., pH, E<sub>H</sub>, and/or DOC) of the groundwater are changing. During the study period, the Bonnet Carr Spillway was opened in April 2008 and May 2011. The spillway discharges Mississippi River water to Lake Pontchartrain and ultimately to our study area, which is supported by the observation of an extended freshwater signal and low Cs across the Mississippi Sound and Bight during these two spillway openings. Important remaining questions from this study include the extent to which SGD and/or Mississippi River water are necessary for establishment and maintenance of hypoxia in the Mississippi Bight and the reasons for the seasonal change in the direction of the sedimentary V flux.
Microplastics in the Mississippi River System
Year: Authors: Cizdziel J., Scircle A.
Microplastic (MP) concentrations along the northern Gulf of Mexico are among the highest levels reported globally. The most likely source of the plastic pollution is the Mississippi River (MR) which drains much of the central portion of the USA. Yet, surprisingly little is known about the concentrations, types, sizes, and loadings of MPs in the MR and its major tributaries. This lack of data is hindering our understanding of the magnitude and sources of the problem. Because the MR is an intricate system of waterways, tributaries, and commercial routes, an in-depth spatial study is needed to fully assess MP pollution in the system. Our research aims to systematically quantify the concentrations and loads of MPs in the MR system, and characterize their shapes, size distribution, and chemical composition in the MR system - a source of drinking water to over 18 million people. We used Nile Red dye to stain the MPs and fluorescence microscopy to count them, as well as vibrational spectroscopy to the identity the plastics. The morphology of the MPs was dominated by fibers (~75%), followed by fragments (~23%) and beads (~2%), with the proportion of fragments increasing slightly moving down the river. The concentration of MPs is relatively low for smaller tributary rivers (Tennessee and Yazoo) and higher in larger tributaries rivers (Ohio and Missouri), with the later having higher concentrations than the MR itself. Counts and loads of MPs generally increased down the main stem of the MR until past New Orleans, where loads declined, possibly due to deposition with slowing water. Sites near population centers (e.g. Memphis) had higher MP concentrations. Overall, this work is an important first step to assess possible relations between MPs levels and characteristics with sources and different watershed attributes.
The presence of dissolved iron in ground and surface waters of the Yazoo Basin
Year: Authors: Tran G., Johnson D.
The U.S. Army Corps of Engineers (USACE) is assisting the Agricultural Research Service (ARS) in the design and construction of a pilot groundwater injection project in Leflore County, MS. The project will have a single withdrawal well and two injection wells. One aspect of the assistance the Corps consists of obtaining all applicable permits for the wells from MS Department of Environmental Quality (MDEQ). Because the well will require periodic back flushing to remove biofouling of the gravel pack surrounding the well, a National Pollutant Discharge Elimination System (NPDES) permit is required. The permitting process identified iron as a potential contaminant of concern. Groundwater samples obtained from sites close to the injection site had dissolved iron concentrations which exceeded the chronic aquatic life criteria (CALC) for iron (1.0 mg/l). The USACE has designed a water treatment plant to remove the iron, but use of such a plant may affect the viability of a large scale implementation of injection project to restore the declining alluvial aquifer. As the Mississippi Delta has more than 20,000 existing irrigation wells, which discharge excess irrigation water in the Delta's lakes and streams, the USACE conducted a study to determine if there are any indications of existing iron contamination of surface waters. The USACE obtained all available ground and surface water data from the United States Geological Survey National Water Information System (USGS NWIS) database. The average concentration of iron in groundwater is 600 ppb, and is more than 50 times greater than the average surface water concentration. Occasional surface water samples did exceed the ALC, but these instances were extremely infrequent.
The Use Drop Pipe Inlet Structures in the Big Sunflower Watershed Basin as a BMP for Erosion Control
Year: Authors: Johnson B.S., Johnson D.
The Flood Control Act of 1944 provided authority to the United States Army Corps of Engineers (USACE) to implement actions to enhance flood control in the Upper Mississippi Delta through the use of channel improvements along the major tributaries within the Big Sunflower Watershed Basin. During the same timeframe significant areas of forestland were cleared to make way for the growing demand of agricultural production. Local drainage districts were formed to improve drainage. These drainage districts often dug numerous ditches, many of which were often hydraulically oversized. As a result, these oversized ditches provided for conditions conducive to significant headcutting in the channels and on the adjacent land. These combined actions significantly increased the runoff and flow rates in the available channel system which in turn caused excessive erosion of the land adjacent to the primary channels. In an effort to counter these aggressive erosional features taking place throughout the basin, USACE was charged with developing a number of best management practices (BMPs) to address the resulting erosion. One of these BMPs is the construction of drop pipe inlet structures. USACE has completed approximately 100 of these BMPs in the Big Sunflower Basin and plans to complete many more to counter the persistent problem.
Climate Extremes and Cover Crop Influence Yields and Water Use of a Maize-Soybean Cropping System
Year: Authors: Li Y., Tian D., Feng G., Feng L.
Climate extreme events in the forthcoming decades are most likely to affect agriculture production and water consumption. Cover crops could be potentially considered as a strategy to mitigate the negative effects of climate extremes. However, extreme climate events were not well determined, and how will the cover crop affect each water balance component under different climate extreme conditions has not been fully explored in Mississippi State. In this study, future climate data were projected under two Representative Concentration Pathways (RCPs) 4.5 and 8.5 from statistically downscaled outputs of ten GCMs (General Circulation Models) provided by Coupled Model Inter-comparison Project - Phase 5 (CMIP5). A variety of diagnostic methods were used to determine extreme temperature, heavy precipitation, and drought based on data in the past (1956-1985), present (1986-2015), and future (2020-2049 and 2050-2079). Then the calibrated and validated model, Root Zone Water Quality Model version 2 (RZWQM2), was applied to simulate crop yields, evapotranspiration (ET), seepage, and runoff under historical and projected future climate extreme conditions for cover crop and non-cover crop scenarios in Pontotoc, Mississippi. A set of climate indices were calculated using daily data during growing season to investigate relationships of climate indices, crop yield and water balance components. The effect of cover crop on crop yield, ET, runoff and percolation under different climate extreme conditions in a Maize-soybean Rotation cropping system will be presented and discussed.
Making Civic Engagement More Accessible and Measurable
Year: Authors: Cossman R.E., Ziogas I.
Regulatory agencies, grant-making foundations, and those with an interest in the environment recognize both the value of, and need for, civic engagement, however it is defined. For example, regulatory agencies recognize that once they move their focus, and resources from a designated area, there is still the need for sustained environmental stewardship at that site. In our EPA-funded study we explored how civic engagement was defined and viewed, how "success" was measured and how environmental outcomes were quantified. Now we pivot to how can we make the civic engagement process more accessible, and how can we measure impact and how can we nurture sustainability.</br></br> Generally, we found that "civic engagement" (as it relates to environmental issues) is poorly defined, the process is inadequately understood, and there is a lack of metrics by which to measure impact or success. These finding starkly illustrate both the current gaps in the field as well as the need to develop operational definitions and metrics. Both regulatory agencies, who expend public funds, and private foundations, are in serious need of metrics that can measure outcomes and accountability.</br></br> We offer three actionable recommendations towards developing actionable Environmental Civic Engagement (ECE) measurements:</br> (1) The creation of an "umbrella" organization, or center, that will facilitate interdisciplinary discourse and cooperation with funding agencies and government authorities on the subject of ECE.</br> (2) The development of a clear and concise programmatic research agenda.</br> (3) Establishing a common repository of ECE-driven data.</br></br> Moving forward we hope to develop a collaborative research agenda with the input and support of regulatory agencies and private foundations.
Dam Decommissioning
Year: Authors: Atkins J.
The Mississippi Department of Environmental Quality (MDEQ) Dam Safety Program is responsible for regulating dams across the State of Mississippi. Excluding NRCS watershed dams, over 90% of the dams regulated by the Dam Safety Program are owned by private entities, such as individual citizens, homeowners association, etc. If a dam is reclassified from low hazard to high or significant hazard, the cost to bring the dam into compliance with the regulations can often exceed the financial ability of the dam owner. In these cases, owners sometimes choose to drain and breach the dam. Information will be presented on the processes and procedures utilized by the Dam Safety Division to have a dam safely breached and removed along with some case studies of dam removals.
Managing the State's Inventory of Dams
Year: Authors: Myers D., Watts J.
The Dam Safety Division of the Office of Land and Water Resources (OLWR) within the Mississippi Department of Environmental Quality (MDEQ) is tasked with regulating dams within the state to protect downstream lives and property. The original inventory of dams was completed in the early 1970s prior to the passage of legislation in 1978 creating a state dam safety program. This inventory was updated during the early years of the program but did not undergo any major updates until 2013. To expedite the process of updating the inventory, the program created Geographic Information Systems (GIS) tools to automate many of the steps used to locate and properly classify dams. Information will be presented on the evolution of the state's inventory of dams, the number and beneficial uses of dams, the GIS tools and procedures created, and ongoing efforts to improve and maintain the inventory to better protect the public.
Science-based land conservation prioritization framework: an overview
Year: Authors: Samiappan S., Linhoss A., Evans K., Roberts J., Liu J., Shamaskin A.
The overwhelming consensus among the conservation experts is the immediate requirement for an efficient data-driven science-based geospatial conservation prioritization tool that can help guide or optimize the dollars spent on land conservation. In this work, we propose a framework for conservation prioritization that enables integration of 1) openly available peer-reviewed data from federal and state agencies, 2) the priorities and values identified in local and regional plans with those identified by stakeholders representing local and regional agencies and organizations. The framework developed as part of this work is implemented as a web geospatial tool. In this work, a multi-criteria decision analysis method is adapted for a conservation decision support problem. The tool was developed and tested with five conservation goals proposed by Gulf of Mexico Restore Council were used as a framework for grouping the identified conservation plans and projects. The goals are 1. Restore and Conserve Habitat, 2 Restore Water Quality, 3. Replenish and Protect Living and Marine Resources, Enhance Community Resilience, and Restore and Revitalize the Gulf Economy. A series of five charrettes were conducted with stakeholders in the coastal states to validate the developed tool and get feedback. The goal of this project is to develop science-based land conservation planning tools that can help the Gulf Coast Ecosystem Restoration Council members to identify and evaluate potential land conservation projects and strategies.
Assessment of Marsh Terraces Performance in Coastal Louisiana U.S. using Multi-Temporal High-Resolution Imagery
Year: Authors: Osorio R.J., Linhoss A., Dash P.
Coastal Louisiana is facing wetland loss and land cover change. Their marshes are drowning due to land subsidence and sea-level rise. Marsh terraces are one of the many techniques that can be applied for wetland restoration by reducing wave energy in the northern Gulf of Mexico. Marsh terraces are segmented ridges of soil that are built in inland, shallow coastal ponds. They are designed to increase marsh area, dissipate wind driven waves, and encourage marsh expansion. Marsh terraces have been implemented for almost 30 years; however little research has been conducted to determine their effectiveness.</br></br> The objective of this study was to assess the change in marsh terrace area over time through remote sensing and change detection analysis. This analysis was conducted using 1-meter resolution imagery from the National Agriculture Imagery program (NAIP) from 2003 until 2017 from five Louisiana coastal Parishes. Marsh terrace sites of at least 10-14 years old were selected randomly within each Parish. Results show more cumulative deposition than erosion in marsh terraces. These results also show that terraces, which have adjacent channels, and thereby an external supply of sediment, show more deposition compared to terraces within enclosed lakes. In the future, the results obtained from this study will be also related with terrace design and environmental factors to understand which features influence marsh terraces erosion or deposition, determine trends in marsh terrace performance and possibly understand which design is most effective when accomplishing their restoration goal.
Evaluation of 1-Day–1%AEP Rainfall Depths in Mississippi
Year: Authors: Kronkosky B.C.
In Mississippi, the Federal Emergency Management Agency (FEMA), National Flood Insurance Program (NFIP), insures ~64,000 policies that total ~$16M dollars (9/30/2017 FEMA statistics)—in aggregate (since 1978), Mississippi has contributed to ~60,000 insurance claims that have exceeded $3B dollars. In almost all instances NFIP "base flood" flood plains are delineated using 1-day–1% rainfall depths (100-year floodplain). In 2013, the National Oceanic and Atmospheric Admiration (NOAA) released "NOAA Atlas 14—Precipitation-Frequency Atlas of the United States, Volume 9, Version 2,"—the most current source for establishing 1-day–1% rainfall depths for Mississippi (and other neighboring states). In addition to Atlas 14, there are seven other studies, dating as far back as 1917, which define 1-day–1% rainfall depths for Mississippi. <br><br>In this investigation, we present a detailed review of these rainfall depths (5 of the 7 studies) using Mississippi county centroids (88 counties). Homogeneous statistical tests are utilized to show differences amongst these estimates, which indicate most estimates are within 10%. It is also shown these studies are bound by each other's standard error, indicating these estimates are statistically indistinguishable (within margin of error). These results suggest 1-day–1% rainfall depths (for Mississippi) have not significantly changed in over 100 year of research, and that methods used 100 years ago produce near identical results as modern-day studies (e.g. Atlas 14).<br/><br/>Attendees will be presented with a breadth review of these historical studies and detailed comparison of their estimates. The objective is to demonstrate that newer research should not necessarily supplement historical practice unless there are significant differences. This calls to question…is newer better, or are we over complicating how 1-day–1% rainfall depths are prepared.
The Southeastern Partnership for Forests and Drinking Water
Year: Authors: Morgan R., Weismann K.
The USDA Forest Service (USFS) and the US Endowment for Forestry and Communities are collaborating with several Southeastern states on the Southeastern Partnership for Forests and Water (the Partnership). This initiative began in 2012 when South Carolina Rural Water Association conducted a high-level, collaborative, multi-state meeting in Greenville South Carolina among state drinking water and forestry agencies, associations and conservation groups. The gathering provided information about the importance of drinking water and forest lands, forestry and drinking water perspectives, and creative financing tools for drinking water protection (referred to as source water protection) in forested watersheds. The initiative recognizes that healthy forests benefit source water quality and quantity. Stewarding, enhancing and maintaining healthy forests in key Southeastern drinking water source watersheds is necessary due to increasing population growth and urbanization in the Southeast, which is resulting in forest fragmentation, forest losses, and a decline in forest health. The purpose of the initiative is to maintain healthy watersheds that provide safe, reliable drinking water, healthy forests, and strong local and regional economies. After the initial meeting in South Carolina the Partnership was formalized. Eight southern states including Alabama, Arkansas, Florida, Georgia, North and South Carolina, Texas and Virginia are now actively involved Partnership. This presentation will discuss the goals, strategic plan and activities of the Partnership along with initial results from state efforts. Attendees at the presentation will acquire appreciation of the value of collaboration between the forestry and drinking water sectors, how the Partnership has operated, and what outcomes may be realized through collaborative projects.
Lead Contamination in Drinking Water and Associated Housing Characteristics in the Mississippi Delta
Year: Authors: Willett K.L., Otts S.S., Woo L., Fratesi M.A., Haggard R., Janasie C., Thornton C., Rhymes J.
This project aimed to create an atmosphere of community and inclusion in order to inform and influence a major public health issue, namely lead contamination of drinking water. Community-based participatory research enabled an assessment of residential drinking water supplies in the Mississippi Delta. We partnered with multiple community organizations to test lead concentrations in drinking water and survey residents about their housing characteristics. Through variously styled community events, drinking water from 215 homes in Mississippi were analyzed for pH and lead concentrations, representing a 74% bottle return rate. The highest concentrations were associated with a targeted private well owner event. Detectable lead concentrations were found in 61% (n = 122) of samples ranging from 0.06 to 14.3 ppb. Of the 122 samples with detectable lead, 9 exceeded 5 ppb. Participants from these homes were provided a certified sink filter. The pH of the waters ranged from 5.84 to 9.13. Five of the nine samples with lead concentrations > 5 ppb had pH < 7 suggesting a correlation between acidic water leaching lead from pipes. Letters were sent to each participant notifying them of their water results. Demographic data collected from the participants were correlated with U.S. Census tract data, which allowed us to determine at-risk areas. Outcomes of this research include a system for determining the best community engagement methods for collecting samples and the best methods for identifying at-risk areas. By involving members of the community in the project, we spread awareness and provoked action in order to minimize lead exposure. Ultimately, this project has helped safeguard public health because survey and sampling results contributed to assessment of the risks of lead contamination in Mississippi and guided scalable research and outreach efforts to minimize lead exposure through use of filters and/or behavioral changes. Supported by USGS-MSWRRI.
Mississippi Private Well Characteristics and Well Owner Demographics
Year: Authors: Barrett J.R.
Mississippi citizens who acquire their drinking water from private wells do not have the luxury of knowing the quality of their drinking water on a regular basis unless they are making the effort to have their water screened and tested. Without knowing and understanding the safety of drinking water, private well owners do not know if and when treatment is needed. Approximately 88% of Mississippi citizens are served by one of the 1,100(+/-) public water systems which provide safe reliable water under the regulatory guidance of the Mississippi State Department of Health-Bureau of Public Water Supply. Private well owners are free to own, operate, and maintain their wells because there is no regulatory oversight. For some private well owners, this freedom is welcome but others want to know the quality of their drinking water and best practices for proper maintenance.</br></br> No demographic data about private well owners has been compiled since the 1990 census. Since the inception of Mississippi State University Extension's Mississippi Well Owner Network, demographic data has been collected and workshops have allowed private well owners the opportunity to have their well water screened for bacteria. This presentation will compare demographic data of current private well owners with those from the 1990 census as well as compare to overall Mississippi demographic data. Private well characteristics are also gathered when a well owner has their water screened for bacteria. Characteristics may prove beneficial when analyzed against the presence of bacteria to assist well owners in making improved decisions on the treatment or introduction of treatment to their well water. The concluding data can be utilized to better understand and serve Mississippi private well owners.</br></br> This study should be of interest to representatives of local municipal water systems, local communities, and rural water associations for potential expansion of their water systems. The regulatory oversight of public water systems should promote and produce a safer drinking water supply for Mississippi residents. The study should also be of interest to private well owners as they navigate life obtaining their drinking water from an unregulated source.</br></br> Teaser: Approximately 12% of Mississippians derive their drinking water from a private well and are unaware of the quality of their drinking water. The Mississippi Well Owner Network has created a venue to educate and inform private well owners about their private well and offering bacteriological screening of the well water. Regardless of location or age of a private home well, the water quality should not be assumed or not known.
Private Well Disinfection: Similarities and Disparities Among State Level Protocols
Year: Authors: Barrett J.R.
Citizens who acquire their drinking water from private wells do not have the luxury of knowing the quality of their drinking water on a regular basis unless they are making the effort to have their water screened and/or tested. Approximately 90% of American citizens are served by a public water system which provides safe, reliable water under the regulatory enforcement of their state primacy agency. Private well owners are free to operate and maintain their wells because there is no regulatory oversight. For some private well owners, this freedom is desired but others want to know the quality of their drinking water.</br></br> If bacteria is found in a private well, the standard response is to have the well disinfected or shock chlorinated. The concept of making an effort to kill bacteria in a well is known by multiple terms to explain the process of using chlorine to disinfect. There may also be different causes or events that necessitate well disinfection. Well disinfection may also be performed by the well owner or a well contractor. Regardless of the cause or demand for well disinfection, there needs to be a uniform process to rid the well of bacteria. State level protocols have many variations of the fundamental steps in well disinfection.</br></br> This study should be of interest to state primacy agencies, private well owners, private well contractors, and anyone affiliated with private well disinfection. Studies show the magnitude of difference between public water system and private well bacteriological sample results. Private wells have a significantly higher number of sample results with presence of bacteria. Private wells being generally shallow in depth and possessing no continual disinfection lend to their susceptibility. The expansion of public water systems increases drinking water regulatory oversight which should promote and produce a safer drinking water supply for all citizens. This study will look to lay out a framework for well disinfection and display the lack of consistency among current state level protocols
The Value of On-site Wastewater in Mississippi
Year: Authors: Welch D.
The 2010 US Census lists approximately 50% of the population of MS as living in "rural" areas. The vast majority of the homes & businesses in these areas are served sewer by on-site wastewater treatment and disposal systems. This presentation will focus on the economic and societal value of serving areas with sewer that might not otherwise be habitable. It will also focus on the potential costs and issues associated with malfunctioning on-site wastewater disposal systems and issues that currently face the Mississippi State Department of Health in regulating the usage of on-site wastewater treatment and disposal systems. There will also be a focus on the attitudes of the wider public as it relates to on-site wastewater treatment and disposal.
Emergancy Action Plans (EAPs) vs Actual Dam Events
Year: Authors: Graham Q.
All high hazard dams in the state are required to have an Emergency Action Plan (EAP). The EAP contains procedures for detection, notification, and evacuation in the event of an incident or failure at a dam. The goal of the EAP is to have a plan in place which will allow for a rapid response so that efforts can be made to intervene and prevent the failure or to evacuate residents downstream in order to prevent loss of life. However, dam failures don't always go according to the plan. Information will be presented about EAPs and the information they contain as well as case studies on real life responses at dam failures and incidents and how they compare to the EAP process.
The Regulatory Process of Inspections and Compliance
Year: Authors: King P., Cummings A.
The State of Mississippi requires that high and significant hazard dams are inspected annually. While owner inspections are allowed, at least every 5th year the owner must hire a licensed professional engineer to perform the inspection. These inspections help the Mississippi Department of Environmental Quality (MDEQ) Dam Safety Division assess the condition of each dam and identify needed repairs. The Dam Safety Division assists dam owners in identifying critical repairs to safely maintain their dams and to comply with State regulations. If the required actions are not taken, enforcement procedures are necessary. MDEQ has broad authority to take necessary actions to get deficient dams into compliance, such as imposing penalties to draining the lake and breaching the dam. This presentation will focus on the inspection process and explain the methods used to ensure all high and significant hazard dams are compliant with State Regulations.
DSS-WISE Web: A Web-Based Automated Modeling, Mapping and Consequence Analysis Tool for Improving Dams Safety in the USA
Year: Authors: Altinakar M., MgGrath M., Ramalingam V.
The National Inventory of Dams (NID) includes the records of more than 90,000 dams classified in three hazard classes: high-hazard (HH), significant hazard (SH) and low-hazard (LH). Although required by law, 17.1% of 15,498 HH dams and 13.1% of 11,883 SH dams do not yet have an emergency action plan (EAP). Moreover, some of the existing EAPs are outdated or do not meet the standards set by FEMA and/or the individual states. About 65% listed in the NID are privately owned, but the safety of the dams is under the responsibility of the states. Unfortunately, many dam owners do not fully understand their personal liability in case of a failure and/or may not have the funds to hire professional services of an engineering company to establish an EAP. The state dam safety offices needed a reliable and accurate tool for dam-break modeling to track the hazard classification of their dam portfolio, which may change based on downstream development, and to provide up-to-date EAPs.</br></br> Funded by FEMA through a sole-source contract, NCCHE developed a web-based, automated two-dimensional dam-break flood modeling and mapping tool called DSS-WISE Lite, which is accessed through DSS-WISE Web secure web portal. The DSS-WISE Web portal was released on November 8, 2016. A graphical user interface with a map server assists the user to set up simulations quickly and efficiently by responding to a small number of questions. The input files needed for the numerical model are automatically prepared using various national data layers, such as NID, USGS 1/3 arc-second digital elevation model (DEM) tiles, National Levee Database (NLD), National Land Cover Database 2011 (NLCD2011), and National Bridge Inventory (NBI). Resampled at the user-specified resolution (20 to 200 ft.), the DEM serves as a regular Cartesian computational grid. The levees from NLD and the estimated reservoir bed topography are burned into the computational grid. The simulation engine uses a shock-capturing upwind scheme to solve the conservative form of full dynamic shallow-water equations discretized over the complex topography using finite-volume method and handles mixed-flow regimes, wetting and drying and discontinuities, such as jumps or traveling positive waves. The results can be viewed on a map server on the Status and Results page of DSS-WISE Web and downloaded onto the user's computer for further analysis. Recently, a post-processing module called DSS-WISE HCOM was released under DSS-WISE Web to provide an estimation of the human consequences of the dam-break floods based on the results of DSS-WISE Lite simulation. This module provides flood danger maps for different categories of population and the evolution of nighttime and daytime population at risk (PAR) by hazard classes using LandScan USA data layers developed by Oak Ridge National Laboratory.</br></br> This presentation briefly presents the capabilities of the DSS-WISE Web portal, which is being used by 730 users from numerous federal agencies and 35 state dam safety offices. As of mid-February 2019, the system handled 13,836 simulation requests and performed 10,623 dam-break flood simulations for more than 3,000 dams. The computational performances of the DSS-WISE Lite system, which returns 85% of the simulation results to the user within 30 minutes, has made it an extremely valuable real-time emergency management tool. Exampled of the use of DSS-WISE Web as a tool for preparedness and emergency response planning are discussed.
Further Developments of the Hydrodynamic/Water Quality Model for Oyster Restoration in the Western Mississippi Sound
Year: Authors: Armandei M., Linhoss A.
The development of a hydrodynamic and water quality model for the Western Mississippi Sound is addressed here. The hydrodynamic part of the model simulates flow, salinity, and temperature. The hydrodynamic part of the model is also the driving mechanism for nutrient transport. The water quality part of the model simulates the physical, chemical, and biological characteristics of Western Mississippi Sound. The model has been developed using the Visual EFDC program that links the hydrodynamic model to the water quality model. A computational grid has been generated consisting of 4 layers, each having 3000 cells. The input data for the hydrodynamic model are; water level, water temperature, salinity, precipitation, solar radiation, wind speed, wind direction, air pressure, and air temperature. The input data for the water quality model are; dissolved oxygen, nutrients (such as Carbon, Nitrogen, Phosphorus and their compounds) and Algae. The simulation time period is from Jan 1st, 2009 to Dec 31st, 2017. The hydrodynamic part of the model is finalized, whereas the water quality part is still being calibrated. The model will be used to identify the most appropriate locations for oyster bed restoration and cultch deployment in the Mississippi Sound.
Comprehensive review of plans, priorities and efforts for land conservation along the Gulf of Mexico coast
Year: Authors: Linhoss A., Evans K., Samiappan S., Liu J., Roberts J., Shamaskin A., Ashby S.
This study reviews past, current, and future land conservation priorities in the Gulf of Mexico coastal region. The review catalogs an extensive list of projects and plans proposed and implemented at federal, state, county, and city levels with direct ties to land conservation during the past 20 years. Five conservation goals proposed by Gulf of Mexico Restore Council were used as a framework for grouping the identified conservation plans and projects. The goals are: 1) Restore and Conserve Habitat, 2) Restore Water Quality, 3) Replenish and Protect Living and Marine Resources, 4) Enhance Community Resilience, and 5) Restore and Revitalize the Gulf Economy. A series of five charrettes were conducted with stakeholders in the coastal states to validate the catalog and add missing projects and plans. A geospatial web tool has been developed as part of this work to allow for identification and exploration of plans in the region. This review also investigates the associations between the Restore goals and conservation priorities among states and different geographic extents. The review suggests that (across the different states, and geo-extents) there is a considerable dependence between the focus of conservation plans and the geo-extent the plan originated. This study is the first large-scale regional assessment of conservation planning efforts across governmental and non-governmental organizations encompassing all ecosystem types in the Gulf of Mexico. This comprehensive analysis at the Gulf Coast Region level is vital to understand the key factors that may drive conservation efforts, as well as identify potential gaps in conservation planning efforts. A holistic understanding of the origin of conservation plans and their relationship with respect to Restore Council conservation goals can be useful in understanding and aligning conservation planning efforts to funding opportunities associated with Restore goals.
Groundwater Recharge from Oxbow Lake-Wetland Systems to Alluvial Aquifers
Year: Authors: Gratzer M., Davidson G., O'Reilly A.M., Rigby J.R.
Knowing recharge rates and understanding recharge mechanisms are crucial to managing water resources. Groundwater recharge from oxbow lake-wetland systems to alluvial aquifers is poorly understood. The aim of this study is to determine whether Sky Lake, an oxbow lake-wetland system in northern Humphreys County, Mississippi, provides significant recharge to the Mississippi River Valley Alluvial Aquifer (MRVAA). To answer this question, we monitored lake-wetland stage and groundwater levels in the wetland and around the entire lake-wetland system from December 2016 to October 2018. Our analysis indicates that Sky Lake provides significant recharge to the MRVAA, based on a groundwater ridge located beneath the lake, groundwater responses to surface-water changes, and a higher correlation between groundwater level and lake stage than between groundwater level and rainfall intensity. Possible recharge mechanisms include preferential flow paths created by tree limbs and roots buried in the wetland sediment as well as coarse-grained point bar deposits near the east side of the lake. Oxbow lakes are created as river meanders and tend to have forested wetlands in the Lower Mississippi River Valley. Therefore, the recharge observed at Sky Lake likely occurs at other oxbow lakes. Similar studies could be carried out at these other lakes, monitoring lake-wetland stage and groundwater levels over time to test whether these lakes significantly recharge the alluvial aquifer.
Assessment of Vadose-Zone Recharge Wells in the Mississippi River Valley Alluvial Aquifer as an Artificial Recharge Method
Year: Authors: Kwak K., O'Reilly A.M., Rigby J.R.
Increasing concerns regarding depletion of groundwater in the Mississippi River Valley alluvial aquifer in the Delta region of Mississippi have led to a need to augment natural recharge. Infiltration basins are often one of the simplest means of artificially recharging aquifers. However, the Delta has a layer of clay and silt at the surface, so it is a better idea to use vadose-zone recharge wells that are not limited by the surficial layer of fine soils. The purpose of this study is to use full-scale field testing to assess the feasibility of using vadose-zone wells for artificial recharge of the Mississippi River Valley alluvial aquifer by using a combination of field, laboratory, and computer simulation techniques.</br> An initial field test indicated each of two vadose-zone wells could intake 100 to 170 m<sup>3</sup>/day by gravity flow. Eight soil samples were collected from the site and their saturated hydraulic conductivities (K<sub>sat</sub>) and wetting/draining curves will be determined using falling head permeability test, METER Hyprop, and hanging water-column method. An axisymmetric model was developed using VS2DTI software from the USGS. The simulations were run with a range of K<sub>sat</sub> and porosity (n) values. The results of the simulations show that head changes at the nearest monitor well are likely to be smaller with a greater ratio of K<sub>sat</sub>/n and vice versa. A final full-scale field test will be performed by simultaneously running multiple (up to four) vadose-zone wells. A three-dimensional variably saturated flow model will be developed to analyze the final test. This research will provide understanding of the hydraulic properties controlling vadose-zone wells and operation of the artificial recharge system. As most alluvial aquifers have similar geological settings as the Delta, results are expected to be relevant to other areas.
The State of Groundwater Assessment in Alabama
Year: Authors: Guthrie G.M.
The Geological Survey of Alabama (GSA) Groundwater Assessment Program has two priorities in support of the development of a state-wide water management plan. The first priority is to monitor the state's groundwaters by: (1) conducting bi-yearly water level sampling, (2) expanding the real-time and continuously monitored well network, and (3) developing a GIS-based well database. The second priority is to utilize information from the initial assessment report entitled "Assessment of Groundwater Resources in Alabama 2010-2016", published as GSA Bulletin 186 in 2018, in conjunction with new data to develop a comprehensive integrated and calibrated water model for the state that will incorporate groundwater, surface water, land use, water use, and climatic data. Alabama's water resources are distributed in diverse settings, so the model will be a composite of subareas defined by HUC-8 boundaries rather than a singular state-wide model. The modeling process will utilize pilot projects representative of the state's aquifers to develop procedures that will be used in subsequent modeling of comparable aquifer environments. Two pilot projects have been initiated: the north Alabama Wheeler Lake HUC-8 and the west Alabama Middle Tombigbee-Choctaw HUC-8, representing the Appalachian Plateau and Gulf Coastal Plain aquifers, respectively. Future pilot projects will focus on basins located in the Valley and Ridge and Piedmont areas of the state. The model is being developed to allow responsible parties to make water-related and policy decisions in response to changing water stresses.
Estimation of groundwater recharge by Chloride Mass Balance (CMB) in the southwestern United States
Year: Authors: Mukherjee A., Holt R.M., O'Reilly A.M.
Groundwater recharge is defined as water flux across the water table from the unsaturated to saturated zone. Recharge is a critical factor in groundwater resource management in arid and semiarid regions and often the most difficult component of the hydrologic cycle to quantify. Recharge is very small in arid and semiarid regions and thus needs to be carefully and accurately estimated. The objective of this study is to calculate recharge in the arid and semiarid areas of the southwestern United States using the chloride mass balance (CMB) method based on numerical simulation. Estimation of recharge using a natural tracer such as chloride (Cl) has the significant advantage of increased sensitivity at lower recharge rates. The HYDRUS 1D computer code was used to simulate water flow and solute transport for four sites: High Plains (HP), Eagle Flat (EF), Hueco Bolson (HB), and Amargosa Desert (AD). The entire unsaturated zone, extending from land surface to water table, was simulated at each site in this simplified modeling approach. Assigned conditions are assumed to be representative of long-term average conditions, circumventing the diurnal and seasonal variation of complex water flux dynamics, especially in the upper part of the domain near the surface. All Cl profiles are bulge shaped with low concentrations near land surface, increasing to peak concentrations at depth assumed to be root zones, and then decreasing to a more or less constant concentration with depth. Recharge fluxes were calculated based on Cl concentrations beneath the bulges. Recharge rates calculated using the CMB method from the four sites are 3.67 mm/yr for HP, 0.03 mm/yr for EF, 0.1 mm/yr for HB, and 8.64 mm/yr for AD, which represent <1%, <0.01 %, <0.05 %, and 8% of mean annual precipitation of each respective site.
The influence of Submarine Groundwater Discharge on the quality of Mississippi coastal waters: example of hypoxic events in summer 2016 and 2017
Year: Authors: Sanial V., Shiller A., Moore W.
The quality of the Mississippi Sound and Bight ecosystem, and as a consequence of economic activities such as tourism and fisheries, is directly affected by land-derived chemical elements. Rivers supply large amounts of allochthonous nitrogen that impact the ecosystem by stimulating primary production, which sometimes leads to coastal eutrophication as well as harmful algal blooms. The Mississippi Sound and Bight, located to the east of the Mississippi River Delta, experience hypoxia that is often attributed to nutrient-rich Mississippi River waters. However, oxygen isotopes show a limited influence of the Mississippi River waters in the Mississippi Bight in spring and summer 2016, but rather a dominant freshwater source originating from local rivers with much lower nutrient concentrations. Therefore, we hypothesize that there is likely an additional factor, namely submarine groundwater discharge (SGD), that significantly impacts the quality of Mississippi coastal waters by playing a role, in particular, in hypoxia. SGD is a hidden pathway for the transfer of chemical substances (such as nutrients, metals, and pollutants) from the land to the coastal ocean. Unlike rivers, SGD is difficult to monitor due to its diffuse nature, which limits the use of direct physical measurements. Tracing techniques, measuring geochemical species such as radium isotopes (Ra) that are naturally enriched in groundwater, constitute a powerful tool to assess the extent of SGD influence in the coastal zone. Hypoxic Mississippi Bight bottom waters in summer 2016 were enriched in Ra, but also in barium (Ba), and nutrients that cannot be accounted for sediment diffusion or river inputs, which suggests the presence of SGD. Spatial distribution in bottom water concentrations of certain dissolved trace elements (e.g., Mn, V, REEs) also suggests spatial differences in fluxes of species from the sediments are affected by bottom oxygen. Further evidence of SGD comes from the increase of Ra associated with a rise in nutrients and methane in coastal Mississippi Sound waters shortly after a Jubilee event in July 2017.
Submarine Groundwater Discharge (SGD) in the Mississippi Sound and its Potential Links to Hypoxia
Year: Authors: Moody A., Shiller A.M., Sanial V.
Submarine groundwater discharge (SGD) in the Mississippi Sound is an understudied component of nutrient and trace metal cycling. Submarine groundwater discharge is the combined flow of freshwater from aquifers and the recirculation of seawater through sediments that occurs along the coastline and across the continental shelf. In July 2017, a low oxygen (less than 2 mg/L) event occurred in the Mississippi Sound causing a "jubilee" event, where large masses of demersal organisms came towards shore. We collected water samples at five locations along Mississippi beaches and analyzed them for chemical species typically enriched in SGD (e.g., Ra isotopes, Ba, methane). During this period of low oxygen there were increased groundwater signatures, suggesting a correlation between the hypoxic conditions and groundwater release. Dissolved methane (CH<sub>4</sub>) and <sup>224</sup>Ra (half life = 3.66 d) were significantly higher than what we observed during more normal conditions. The high levels and short half lives of both indicators suggest that there was a recent release, and nearby source, of groundwater. Historically, low oxygen events have been observed in the Sound, so it is important to understand what causes them. Our results suggest that understanding the origins and forcing factors for local SGD may be an important aspect of predicting and managing hypoxia in the Sound. In order to determine if SGD may enhance or lead to hypoxia in the Mississippi Sound, an ongoing time series along the coastline has been collecting radium, nutrients, barium, and oxygen data. In order to understand if there are spatial components of SGD, radon surveys are also being conducted throughout the Sound. Preliminary results indicate that SGD is highest along the coastline. However, more work is needed to determine the sources and impacts of SGD within the Mississippi Sound.
Ecological Agriculture Application with Winter Flooding
Year: Authors: Firth A., Baker B., Brooks J., Davis J.B., Iglay R., Smith R.
Rice is the staple food for more than half of the world's population and has the ability to support more people per unit of land area than wheat or corn, as rice produces more food energy and protein per hectare than other grain crops. However, with the human population projected to reach 8.5 billion by 2030, there are major concerns about the sustainability of rice production practices because of its major contribution to water pollution and soil degradation. Thus, there is a need to identify sustainable production practices that minimize environmental damage, while also remain economically feasible. This study investigated a potentially sustainable rice production system in the Mississippi Alluvial Valley (MAV) that uses ecological principles to enhance environmental quality and economic gain at the field scale. It was hypothesized that the annual flooding of rice fields to create water bird habitat would benefit soil health, and in turn water runoff, providing agronomic benefits to the farmer alongside environmental benefits. Two rice farms were selected that applied different management regimes during the winter: conventional fallow fields and winter flooding. Soil microbial diversity and nutrient content were quantified and compared for a measure of overall soil health. Measured soil health variables linked flooded fields and high bird activity with more nutrient and microbial activity. Evidence from the investigation provided justification for future research, to develop a framework for other producers within the MAV to adopt similar management methods, ultimately improving the overall integrity of soil, water, and environmental quality as well as the farmer lifestyle.
Microplankton trophic dynamics in the northern Gulf of Mexico
Year: Authors: Boyette A.D., Cruz V.J., Graham W.M.
Improved understanding of microplankton (< 200 µm) community dynamics and trophic connectivity between primary producers and heterotrophic protists is central to plankton ecology and water quality studies. Despite their ecological significance in structuring aquatic ecosystems, there is limited knowledge on phytoplankton-microzooplankton trophic interactions in the northern Gulf of Mexico (nGOM). Here we describe the microplankton community structure using a morphological based functional group (MBFG) approach to classify microplankton images obtained from imaging in-flow technology (FlowCAM®), primary production (photosynthesis-irradiance curves, P-E), and phytoplankton apparent growth and mortality (dilution experiments) within inner shelf surface waters of the nGOM during two seasons (fall, spring). Additionally, we evaluated the importance of protist grazers, particularly ciliates, as predators on phytoplankton. Phytoplankton biomass was dominated by diatoms in both seasons, with average chlorophyll a (3.8 mg m<sup>-3</sup>) more than twice that of fall (1.7 mg m<sup>-3</sup>). Needle-like (Pseudo-nitzschia sp.) and cells with setae (Chaetoceros sp.) were the predominant diatoms, whereas small (<20 µm) cryptophytes, prymnesiophytes, and Heterocapsa sp. dinoflagellates comprised more than 80% of the flagellate community in both seasons. Aloricate choreotrichid ciliates (Strombidium sp., Strombilidium sp.) were the primary microzooplankton grazers, though >50% of the ciliates were mixotrophic the Mesodinium rubrum. Phytoplankton potential production (0.01 x 0.38 gC m<sup>-3</sup>d<sup>-1</sup>) and apparent growth (0.01 x 2.53 d<sup>-1</sup>) were greater in spring, although highest maximum photosynthetic rates (PBmax = 34.07 g C g Chl<sup>-1</sup> h<sup>-1</sup>) were measured in fall. Microzooplankton consumed ~ 40% phytoplankton biomass and > 65% of the daily primary production. The ratio of microzooplankton grazing to phytoplankton growth (m:µ) averaged 1.14, suggesting that microzooplankton grazing is an important top-down control on phytoplankton biomass in this system.
Irrigation Water Use Efficiencies of Twin-Row vs. Single-Row Soybean in the Humid Mississippi Delta
Year: Authors: Pinnamaneni S.R., Anapalli S.S., Reddy K.N., Fisher D.K., Bellaloui N., Sui R., Boykin D.L.
In the humid climate of the Mississippi (MS) Delta, high intra-seasonal variability in the rainfall received during the critical periods of crop growth often makes irrigation necessary to maximize crop yields. Farmers in this region, generally, meet their crop irrigation water demands by pumping water from the shallow MS valley alluvial aquifer underlying this region. However, water withdrawal beyond the aquifer's natural recharge levels is resulting in significant groundwater-level declines, thereby threatening future water availability. A field study was initiated in the summer of 2018 to compare the water use efficiencies between twin-row and single-row planted soybean (Glycine max L.) cropping system under varying irrigation levels in a Dundee silt loam soil in the humid climate of MS Delta. The soybean was planted on ridges spaced 102 cm apart and furrow irrigated. In the twin-row plantings, soybean was planted in two rows of 25 cm apart on a 102 cm center. The experimental design used in this study was a split-plot with irrigation as main unit and row spacing as subunit, replicated six times. Irrigation levels were full irrigation (FI), half irrigation (HI), and rainfed (RF). Irrigations were scheduled based on soil water measurements. Twin-row planting had a significant impact on grain yield over single rows in all the irrigation treatments (5.03 t ha<sup>-1</sup> vs. 3.01 t ha<sup>-1</sup> RF; 5.70 t ha<sup>-1</sup> vs. 3.84 t ha<sup>-1</sup> HI and 6.14 t ha<sup>-1</sup> vs. 5.06 t ha<sup>-1</sup> FI). Similarly, seed test weight increased considerably due to irrigation: 14.76 g RF vs. 16.29 g HI vs. 17.79 g FI in single rows and 14.76 g RF vs. 16.67 g HI vs. 17.48 g FI in twin rows, respectively. Nutritional quality was assessed using a standardized near-infrared reflectance (NIR) diode array feed analyzer protocol. Significant enhancement in the levels of seed protein, palmitic acid, aspartic acid, glycine, methionine was observed in FI and HI while sucrose levels were elevated in the rainfed soybean. The growers can consider transitioning to twin row system of soybean production with alternate row irrigation during critical periods of crop growth for enhanced water use efficiency and crop profitability.
Contrasting Evaportransporation Requirements of Staple Row Crops in the MS Delta
Year: Authors: Anapalli S.S., Reddy K.N., Krutz J.
Aquifers all around the world, that took millions of years to fill are being depleted due to unsustainable water withdrawals for crop irrigation. The Mississippi (MS) Delta, one of the most important agricultural production regions in the USA, relies mostly on water from the MS River Valley Alluvial Aquifer for irrigation needs. Soybean represents about 53% of the irrigated area, while the remaining shared between other crops and aquaculture. Pumping water from this shallow aquifer beyond its natural recharge levels has already resulted in significant aquifer declines, threatening the future of irrigated agriculture in the MS Delta. Accurate information on crop evapotranspiration demands (consumptive water requirements; ET) of staple crops in the MS Delta is essential for developing environmentally and economically sustainable water management practices. We quantified ET of corn (a C4 crop) and soybean and cotton (C3 crops) in a predominantly clay soil under humid climate in the Lower MS Delta using the eddy covariance method. In 2017 season, corn, soybean, and cotton fixed 31331, 23563, and 8856 kg ha<sup>-1</sup> of CO2 in exchange for 483, 552, and 367 mm of ET, respectively. Crop durations were 120, 135, and 137 days, respectively for corn, soybean, and cotton. Maximum LAI and average grain yield produced were 5.5 and 12772 kg ha<sup>-1</sup>, 5.5 and 4777 kg ha<sup>-1</sup>, and 3.0 and 1260 kg lint ha<sup>-1</sup>, respectively, for these crops. The seasonal net ecosystem exchange (NEE) of CO2 estimated for cotton was 72% less than corn and 62% less than soybean. Estimated average daily ET of corn was 4.0 mm, soybean was 3.9 mm, and cotton was 3.0 mm. The ecosystem water use efficiency in these three cropping systems were 53, 43, and 24 kg CO2 ha<sup>-1</sup> mm<sup>-1</sup> of water. The WUE in grain production of corn was 26 kg ha<sup>-1</sup> mm<sup>-1</sup> and soybean was 9 kg ha<sup>-1</sup> mm<sup>-1</sup> of water. Results of this investigation can help in adopting crop mixtures that are environmentally and economically sustainable, conserving limited water resources in the region.
Soil Health Management Practices for Improving Rain Water Use Efficiency to Stabilize Dryland Soybean Yield
Year: Authors: Feng G., Reginelli D.
Soil health management is essential for sustainability of agricultural production system. Cover crop, manure and biochar have been widely applied for improving soil organic carbon (SOC). However, no consistent results were found whether and how much increasing SOC could improve water holding capacity of different soils. We conducted both field and simulation studies to determine impact of cover crop and amendment of poultry litter and biochar on SOC, soil water content at field capacity (FC) and water use efficiency (WUE). The results revealed that average annual percolation under the wheat cover crop system was decreased by 11%, over 8 decades as compared with the plots without cover crop. Soybean yield and water use efficiency (WUE) were increased by 4% and 9% in the cover crop-based cropping system. Growing a winter wheat cover crop between harvest and planting of soybean improved soil organic carbon by 15%. Application of poultry litter increased SOC ranging from 0.6 to 2.6%. A significant positive linear relationship was found between total carbon (TC) and FC of silt and silty loam soils as TC exceeded 1%. We found that a 1% increase in soil TC can improve soil water holding capacity by 13%. For different soil textures, a strong linear positive relationship was found in coarser soils (clay <20%). The soils from Brooksville had higher carbon content (mean value, 1.59%) and higher FC (34.64%) partly due to manure application than unmanured soils from Stoneville (TC of 0.92% and FC of 30.40%) in Mississippi State. We suggest soil carbon should be increased over 1% by applying manures and biochar or by other means to improve soil water holding capacity and overall soil health.
Increasing Mid-Southern USA Furrow-Irrigation Efficiency through In-Field Cultural Practices
Year: Authors: Bryant C.J., Krutz L.J., Locke M.A., Steinriede Jr. R.W., Spencer G.D.
Declines of the Mississippi River Valley Alluvial Aquifer are currently unsustainable and require changes to current irrigation practices to ensure irrigated agricultures longevity. However, many environmental and economic factors prevent adoption of systems more efficient than the current furrow-irrigation method. Therefore, methods must be developed to increase the application efficiency of current irrigation systems. This study was established in Stoneville, MS to determine the effects of varying tillage systems with and without cover crops on furrow advance time, runoff volume, and irrigation application efficiency in continuous soybean (Glycine max) production. Treatments consisted of conventional tillage/winter fallow (CT/WF), reduced tillage/winter fallow (RT/WF), reduced tillage with in row sub-soiling (RT/SS), reduced tillage with a cereal rye (Secale cereal) cover crop (RT/RC), reduced tillage with a tillage radish (Raphanus sativus) cover crop (RT/TR), zone tillage/winter fallow (ZT/WF), and zone tillage with a tillage radish cover crop (ZT/TR). Furrow advance time was increased by at least 18% by switching to either zone tillage system or a RT/RC system. Utilizing CT/WF or RT/WF soybean production systems increased runoff volumes by at least 41% while reducing irrigation application efficiency by at least 24%. These data indicate that switching to conservation based soybean production systems that include either zone tillage or a cover crop can reduce runoff water volumes and increase application efficiency of Mid-Southern USA furrow-irrigation systems.
Factors Affecting In-Filed Soil Moisture
Year: Authors: Hodges B.C., Tagert M.L., Paz J.O., Reginelli D.
There have been numerous studies on soil moisture as it pertains to irrigation in Mississippi, but more work is needed in the agricultural region known as the Blackland Prairie, located in the northeastern part of Mississippi. Here, an increasing number of producers are showing an interest in irrigation. It is not economical to access groundwater over most of the region due to the depth of the aquifer, so many producers use surface water for irrigation. Sprinkler irrigation is the primary application method, to accommodate the changing topography across the landscape. Soil moisture sensors have been shown to conserve water usage while maintaining yields on irrigated fields, helping to better time irrigation applications with crop water needs. However, more work is needed to determine the ideal number of sensor sets needed over a given area and the best placement of sensors within a field. There are many variables that can affect soil moisture including topography, soil type, and the variability of vegetation. This study is being executed on a 15-ha soybean field under sprinkler irrigation near Brooksville, MS, in the Blackland Prairie region. A 55-m grid was placed over the field, resulting in 44 sample locations; Watermark Granular Matrix soil moisture sensors were installed at 12- and 24-inch depths at each sampling point. The sensors were wired to data loggers, which recorded soil tension measurements hourly. Plant height and leaf area index (LAI) were measured weekly from June 29 through August 17, 2018. Soil texture was measured for each grid point, showing a relatively homogenous field with a silty clay loam as the dominant soil type. Results show spatial differences in soil moisture over time, with more variability when the soil profile is drier.
Investigating the Effect of Habitat Availability and Stream Morphology on Macroinvertebrate Demographics in Red Bud/Catalpa Creek of Northeastern Miss
Year: Authors: Richardson B., Musser S., Ortega-Achury S., Ramirez-Avila J., Martin J.
Rapid bioassessments using macroinvertebrates is one of the most popular ways to gather large amounts of data on stream health in a very short amount of time. A wide variety of indices have been developed to score and weight macroinvertebrate communities for the purposes of evaluating water quality, and many of these are state- or region-specific. However, the use of these indices can often bias results toward better water quality when taken at face-value, as the presence of only one individual of a certain group or species can significantly raise the water quality score of many indices. This study investigated the macroinvertebrate demographics of Red Bud/Catalpa Creek in northeastern Mississippi. The Pollution Tolerance Index (PTI) of the sampled stream reaches reported, almost exclusively, an "excellent" rating. However, community abundances showed that many samples were dominated tolerant taxa while the most intolerant taxa (indicators of good water quality) were represented by 1 or 2 individuals. Community analysis also showed that many stream reaches were vacant, or nearly so, of important functional groups such as scrapers and predators. The absence of these functional groups is likely due, in part, to the absence of adequate habitat and other resources. In one study stream, forested riparian vegetation is restricted to approximately a 200-m section in the upper reaches while the rest of the stream is flanked by thick grasses and invasive shrubs. This restriction of forest vegetation reduces the availability of sufficient food resources for shredders in downstream sections of the stream. The results of this study highlight the importance of ecological metrics and community demographics in the evaluation of stream health. Water quality and stream health indices using macroinvertebrates should be used to support these results of these metrics, not supplant them.
A Market Accessibility Study for the Inland Waterway System in Mississippi
Year: Authors: Puryear S.
In order to find a good beginning point for this study, multimodal freight plans in neighboring states and in Mississippi have been reviewed to determine the level of knowledge about Mississippi's inland waterway assets from a state agency's perspective. In order to assess the accessibility for each port, a quantification method has been investigated and determined. Data and information for calculation are collected and processed currently. An exercise of building a multimodal network has been finished. Network data and impedance evaluation methods have also been investigated and determined. Future network configuration measures have been investigated and determined, including network centrality measurements. </br> In Mississippi, different entities have conducted studies on port development and its economic impact. It is clear that the port authorities need well established marketing strategies and plans to expand market and request funding. Some reports collected profile data about each port, although in different level of details. Important information about port capacity, throughput, efficiency, and commodity type are lacking. UAVs and portable scanning equipment are being coupled to provide accurate scans and input to simulations of inland port infrastructure and operations.</br> The ports included in this study are: Yellow Creek, Port Itawamba, Port Amory, Port Aberdeen, Lucas Port at West Point, Lowndes Co. Port, Rosedale Port, Greenville Port, Vicksburg Port, Claiborne Co. Port, Natchez-Adams Co. Port, Yazoo County Port, Bienville Port, Gulfport Port, and Pascagoula Port.
Evaluating the effectiveness of large-scale living shoreline projects at restoring fringing marshes
Year: Authors: Martin S., Temple N., Palino G., Cebrian J., Sparks E.
In the wake of the Deepwater Horizon oil spill, large-scale breakwater projects have been constructed to restore and conserve marshes across the northern Gulf of Mexico. These breakwater projects are often termed living shorelines, due to the perceived increase in productivity around the breakwaters and within the fringing marsh shoreward of these structures. However, evaluations of the effectiveness of breakwaters at preserving natural shorelines are limited. To evaluate the effectiveness of large-scale breakwaters at protecting or restoring marshes in high wave energy environments, we conducted experimental plantings and a shoreline monitoring program landward of six year old breakwaters (OBW), recently constructed breakwaters (RBW), and reference no breakwater sites (NBW) along Bon Secour Bay, AL. The OBW, RBW, and NBW complexes cover 0.6km, 3km, and 1.2km of consecutive shoreline, respectively. Within the OBW and NBW sites, eight replicates of planted (4m2 of nursery grown S. alterniflora sods planted in checkerboard pattern), natural stand, and no vegetation treatments were randomly distributed throughout each site. Within the RBW sites, an additional planted design was also established (clumped plantings), yielding four shoreline vegetation treatments. Each plot was visited quarterly with a suite of vegetative measurements taken, including: percent coverage, species diversity, biomass, porewater DIN, and soil organic matter. Additionally, the perimeter of all of the natural S.alterniflora patches within each site was field mapped using an RTK GPS and validated with drone imagery to compare S.alterniflora area across breakwater treatments. Preliminary results indicate a positive effect of breakwaters beginning 5 years after construction on naturally colonized S.alterniflora, but no effect on planted vegetation using the fixed monitoring plot data. However, to date, the RTK GPS and drone imagery have shown no discernable effects of the breakwaters on enhancing shoreline vegetation. If these trends continue throughout the duration of the monitoring, they will show that large-scale breakwaters could have marginal effects of preserving and enhancing fringing marsh vegetation in high wave energy environments.
Best Practices and Lessons Learned in using Low-Cost Unmanned Aerial Vehicles for Assessing Erosion
Year: Authors: Czarnecki J., Ramirez-Avila J., Linhoss A., Schauwecker T., Hathcock L.
Unmanned aerial vehicles (UAV) are promoted as an efficient, low-cost tool for aerial survey. This includes not only traditional aerial photography, but also creation of digital surface models. The process, referred to as "structure from motion", has received attention in recent years as a replacement for other field survey techniques such as LiDAR and terrain laser scanning. We collected UAV images with large overlap between successive images over a two-year period to perform structure from motion analysis and monitoring of erosion. The goal of this research effort was to determine the limitations to the technology and the accuracy obtainable. The output of this research effort was best practice guidance for new users of the technology. As a summary of our results, we concluded that UAV images are capable of providing spatially-explicit, fine- to medium-temporal scale data. The output was advantageous for hydraulic models, offering more detailed channel geometry, as well as guidance on friction coefficients. The biggest impediment to accuracy was dense vegetative cover.
Remotely sensing sediment tracers
Year: Authors: Linhoss A., Czarnecki J., Samiappan S.
Tracking the movement of sediment in water is important for understanding the rate of coastal erosion and deposition. This understanding is critical for designing sustainable and resilient coastal infrastructure. Sediment tracers are one of few field techniques that can be used to track coastal erosion and deposition. Traditional sediment tracing methodologies involve recovering sediment samples and extracting the tracer material either by hand (particle by particle) or using magnets. This is an effective but time intensive and costly process.</br></br>This project explores the use of low altitude remote sensing to measure the concentration of sediment tracer in order to understand and track coastal sediment movement. Sand was mixed with various concentrations of fluorescent and magnetic sediment tracer. Samples were placed in containers, outdoors during daylight hours. An unmanned aerial system fitted with a hyperspectral sensor flew over the samples to collect reflectance data. The images were processed to detect the concentration of tracer in each sample. The results from the processed images were compared to the known concentrations. Preliminary results show that, at the plot scale, remote sensing is a promising technique for measuring sediment tracer concentrations. Future work will involve testing the method in field conditions along the Mississippi coastline.
The role of riparian vegetation type in stream water quality conditions
Year: Authors: Musser S., Grafe J., Ortega-Achury S., Ramirez-Avila J.
Stream health can be significantly affected by the type and characteristics of riparian zones along stream corridors. Research is focused on the identification and assessment of habitat, water quality, and flood hazard processes along the main channel and tributaries of Catalpa Creek. Research results would be used to support the implementation of the management plan for this watershed. A study is in progress to compare forested and grassed riparian zones on tributaries within the Catalpa Creek Watershed, in order to better understand their effects on stream water quality and health. Water quality is monitored weekly for parameters such as temperature, dissolved oxygen, pH, and turbidity. Grab samples are also collected and tested for quantification of total suspended solids and nutrients. Temporal and spatial differences in water quality, including changes in temperature, dissolved oxygen levels, and suspended solids will be assessed to determine how they are affected by seasonal changes (i.e. fall and winter) and the riparian zone characteristics (i.e. forested and grassed). Preliminary results indicate poorer stream health in grassed regions than forested regions. Overall, results would strengthen the case for properly maintaining and improving forested riparian zones to provide benefits in water quality and stream health in the Catalpa Creek.
Evaluation of Spatial and Temporal Variation in Stream Water Quality: A Case Study for a Mississippian urban headwater
Year: Authors: Ramirez-Avila J., Ortega-Achury S., Schauwecker T., Czarnecki J., Martin J.
Evaluation of spatial and temporal variation of water quality and identification of pollution sources is very important for effective implementation of watershed management actions/plans. Water quality monitoring data were collected from more than 40 monitoring stations along the main stream and tributaries of the Catalpa Creek between 2017 and 2018. Water quality distribution and characteristics of each stream is evaluated by conducting multivariate statistical analysis for 9 water quality parameters (i.e. temperature, dissolved oxygen, total suspended solids, total nitrogen, total phosphorus, total dissolved solids, pH, turbidity and electric conductivity). Results are expected to indicate if monitoring sites with high levels of pollution are directly affected by the direct contribution of urban or agricultural areas, the differences in type of riparian vegetation, occurrence of in-stream processes and/or seasonal variation of baseflow and stormflow rates. Impairment of waterbodies will be determined based on the study results, and priorities for water quality improvement, items required for watershed management implementation, will be determined for efficient water quality management in terms of future watershed management.
Developing Regional Curves for Stream Restoration in Mississippi
Year: Authors: Ramirez-Avila J., Ortega-Achury S., Martin J., Richardson B.
A long term stream assessment and restoration program is needed in Mississippi and developing Regional Curves is a critical first step toward achieving this goal. This project aims to provide validated tools to aid practitioners and Federal and State agencies in the design, evaluation and implementation of more effective stream and wetland restoration and mitigation projects in Mississippi. Main goal and project tasks will be achieved by using a combination of methods including remote sensing, field reconnaissance, detailed data collection, laboratory analysis and modeling. Project tasks include identification of stream reference reaches to conduct geomorphological and biological assessment and surveys within the Tombigbee River Basin, a representative area for the East Gulf Coastal Plain Physiographic Section and the Coastal Plain Province in Mississippi. Geomorphic and biological surveys will be related to drainage area to develop the Regional Curves and biological community references, respectively. Proposed Regional Curves will be compared to available Curves for the Coastal Plain Province in Alabama, Florida and Georgia. Stream restoration designs for an existing non-functional stream will be developed using both, the new proposed Curves and those from outer state. The new tools are expected to improve stream assessments and designs increasing the effectiveness of stream restoration projects.
Abiotic parameters dictating community composition and the ecological functions of freshwater mussels
Year: Authors: Atkinson C., van Ee B.
Animal aggregations can lead to localized hotspots of nutrient and material flux in streams. Yet, the abiotic characteristics driving the spatial structure of these hotspots due to species-specific preferences remain a mystery. Historically, unionid mussels dominated benthic biomass in many river ecosystems, but have undergone extensive declines. We examined reach-scale physical attributes of sites encompassing a gradient of mussel densities, evaluated quadrat-scale abiotic variables, and the role various species play in nutrient (C, N, P) sequestration and regeneration. We sampled mussels and abiotic variables at 1,218 quadrats, measured tissue nutrient composition and excretion and biodeposition rates of 11 species across 12 reaches in the Sipsey River, Alabama. Using geostatistical analyses, species distributions and their associated ecological functions were mapped and models were developed to examine species distributions and species' roles in recycling and storing nutrients. These models were used to examine species-specific roles in reach- and quadrat-scale nutrient recycling and storage. Our results demonstrate that mussels are important to nutrient dynamics through nutrient regeneration and the creation of storage hotspots, but their significance varies with distribution, species composition, and abiotic context.
Hydrologic and Vegetation Management Influence Oxygen Dynamics and Nitrogen Processing in Experimental Ditches
Year: Authors: Nifong R.L., Taylor J.M., Yasarer L.
With increasing consumer demand for sustainable agricultural production and continued concern for coastal economies, excess nitrogen (N) runoff from agricultural areas remains a major challenge to reducing the environmental footprint of high intensity agriculture. To address this challenge, producers need simple and innovative approaches that reduce runoff from agricultural fields while maintaining high productivity. Agricultural ditches act as the primary water-soil interface on farms and are a pivotal, but currently underutilized, location to implement low-cost management practices to increase both on-farm and landscape-scale mitigation of excess N runoff. Previous small scale experiments have demonstrated good potential for rice cutgrass (<em>Leersia oryzoides</em>) to enhance both N uptake and denitrification in ditch sediments. However, it is unclear how small-scale mesocosm studies and core based methods translate to larger scale observations that incorporate diel patterns in light and temperature, both of which can influence primary production, O<sub>2</sub> dynamics, and related N processing. To inform how ditch management may influence N dynamics at larger spatial and temporal scales, we examined how hydrologic and vegetation management practices interact to influence diel nitrogen and oxygen dynamics by experimentally manipulating hydrologic residence time and the presence of rice cutgrass (<em>L. oryzoides</em>) in six experimental ditches. We measured plant nutrient uptake, denitrification fluxes, and metabolism using in situ dissolved solute and gas sampling techniques over three 24 hour diel experimental runs. Results indicate that ditches with vegetation promote N retention and have more pronounced oxygen dynamics which can alter expected N removal pathways. We will discuss the complexities in outcomes of these management practices within the context of whole system measurements that incorporate diel cycles.
Can Cover Crops and Reduced Tillage Improve Surface Water Runoff Quality and Soil Health in the Mississippi Delta Alluvial Plain?
Year: Authors: Locke M.A.
Cover crops and reduced tillage are in the toolbox of conservation management practices that need to be assessed in the alluvial plain of the Lower Mississippi River Basin to balance goals for production goals with natural resource concerns. Results from a series of USDA-ARS studies in the Mississippi Delta assessing effects of cover crops on water and soil quality in row crops are reviewed here. Synthesis of results from these studies showed that: (a) Cover crop and reduced tillage resulted in moderate increases in soil organic carbon and soil nitrogen at the soil surface; (b) Biological activity in surface soils was enhanced by cover crops (e.g., enzymes, mycorrhizae), but effects diminished with soil depth; (c) Total runoff sediment loss was reduced by no-tillage and cover crop; (d) Nitrogen and phosphorus associated with runoff sediment were reduced in no-tillage and cover crop; (e) Soluble nitrogen and phosphorus in runoff was variable, and was sometimes higher in no-tillage and cover crop areas.
Assessing Water-Quality Changes in Two Oxbow Lake Tributaries of the Mississippi Delta
Year: Authors: Murphy J., Hicks M., Stocks S.
Many best management practices (BMPs) have been implemented across the Mississippi Delta in an effort to reduce the amount of nutrients and sediment leaving agricultural fields. However, it has been difficult to assess the influence of BMPs because there is often a lack of monitoring of downstream water quality. To this end, the U.S. Geological Survey collected approximately 8-9 years of water-quality and hydrology data at two agricultural ditches that drain row-crop fields and have a variety of BMPs in place in the ditches or fields. These sites discharge into separate oxbow lakes in the Mississippi Delta and previously had been identified as having excessive nutrient and sediment runoff. Using an event-based dataset and bootstrapping techniques, we tested for differences in flow-weighted mean concentrations of nutrients and sediment between an early and late period at each site. Most of the major BMP implementations occurred during in the early period whereas the late period had some additional implementations but typically at a lower intensity. We tested for differences and equivalences in median early and late concentrations and also for differences in the concentration-streamflow relationship between periods. We found several statistically significant decreases in nutrients and sediment at one site but none for the other. Nutrients and sediment were also not found to be equivalent between the early and late periods at either site. This means, while one site had substantial decreases in event concentrations for some constituents, results at the other site were generally inconclusive. These mixed results are likely due to differences in BMP implementation, farming practices, and the data characteristics at these sites.
Effects of Varying Suites of Agriculture Conservation Practices on Water Quality in the Mississippi Delta
Year: Authors: Baker B., Prince Czarnecki J.M., Omer A.R., Aldridge C.A., Kroger R., Prevost J.D.
Increasing concern regarding environmental degradation and annual hypoxic zones has led to the need for mitigation of nutrient laden runoff from inland landscapes. An annual occurrence of a hypoxic zone in the Gulf of Mexico has led to the development and implementation of nutrient reduction strategies at the state level throughout the Mississippi River Basin (MRB). With federal, state, and private financial and technical assisstance, landowners have implemented best management practices (BMPs) to reduce nutrient and sediment loading; however, the effectiveness of these BMPs to improve water quality, alone or utilized together, has not been widely documented. This research includes a field-scale, paired watershed approach in two watersheds in the Mississippi Alluvial Valley to test for differences in sediment and nutrient runoff concentrations between four management systems. Baseflow and stormflow samples were collected from 2011 to 2015 and analyzed for nutrient and sediment concentrations. Median baseflow concentrations across all sites were 52 mg L<sup>-1</sup> for total suspended solids (TSS), 0.38 mg L<sup>-1</sup> for total phosphorus (TP), 0.09 mg L<sup>-1</sup> for nitrate-nitrite (NO3<sup>-</sup>-NO2<sup>-</sup>), and 0.81 mg L<sup>-1</sup> for ammonium (NH4+). Median sediment and nutrient concentrations from stormflow samples across all sites within the study were greater than baseflow concentrations, where median stormflow concentrations were 985 mg L<sup>-1</sup> for TSS, 1.21 mg L<sup>1</sup> for TP, 0.32 mg L<sup>-1</sup> for NO3<sup>-</sup>-NO2<sup>-</sup>, and 1.04 mg L<sup>-1</sup> for NH<sub>4</sub><sup>+</sup>. Results showed no strong improvements in water quality from agricultural landscapes where suites of BMPs had been implemented. Rather, the data presented variability in runoff concentrations indicative of strong influences from environmental and management variables. Study outcomes highlight opportunities to better capture nutrient dynamics at the field scale through adaptive management of BMPs and the importance of in-field practices for improved water quality to improve nonpoint source pollution reduction.
Quantifying Crop Coefficients for Corn Irrigation Scheduling in the Lower MS Delta Using an Eddy Covariance Method
Year: Authors: Anapalli S.S., Reddy K.N., Fisher D.K., Sui R.
The water levels in the Mississippi river valley alluvial aquifer is falling fast due to water withdrawals for crop irrigations that are not replenished with rainfall recharge. Irrigation applications based on the exact crop evapotranspiration demands—consumptive water requirements—can be the way forward for preserving this aquifer-water resources for its sustainable use for irrigations in the region. In this direction, in a pioneering study, we quantified ET<sub>c</sub> from corn using an eddy covariance (EC) approach (ET<sub>e</sub>). In the EC system, vertical velocity of eddy transport and sonic temperature were measured using a Gill New Wind Master sonic anemometer (Gill Instruments), and water vapor density in the eddies was measured using the LI-7500-RS open-path infrared gas analyzer (LI-COR Inc.). All instruments were calibrated once in a year before moving to the field for measurements. The sensors were mounted on a telescopic, height adjustable tower, and the sensor height was maintained at twice the canopy height. Recognizing the unresolved problems in balancing energy fluxes in the EC approach, we also monitored ET<sub>c</sub> by computing latent heat energy flux (LE) from the system following a residual energy balance (EB) approach (ET<sub>b</sub>) using added instrumentation and compared the fluxes. The unclosed energy fluxes in the EC was post-analysis corrected using the Bowen ratio (BR) and LE methods. The measurements were conducted in a 31 ha clay soil field planted to irrigated corn in the lower Mississippi Delta, USA, in 2017. Further, for scheduling irrigations in corn, based on grass and alfalfa reference crop ET calculated from weather data, averages of the ET<sub>b</sub>, ET<sub>ebr</sub>, and ET<sub>ele</sub> daily estimates were used in deriving corn crop coefficients (K<sub>c</sub>).
Improving the Corn Crop Coefficient Method in the Mississippi Irrigation Scheduling Tool (MIST)
Year: Authors: Buka H., Linhoss A., Tagert M.L., Pote J., Wax C.
This study examines the value of improving the crop coefficient method being used in the Mississippi Irrigation Scheduling Tool (MIST). Due to an overall increase in irrigated acreage, irregular distribution of rainfall during the summer growing season and continual decline of the Mississippi Alluvial River Valley Aquifer (MARVA), it is important to implement irrigation management practices that minimize water use without compromising crop production, yield, and quality through use of scientific models and soil monitoring devices. The objectives of this study were to 1) adjust and examine the Food and Agriculture Organization (FAO) crop coefficient method and the adjusted "SCS polynomial crop coefficient" method adapted and digitized from the former Soil Conservation Service (SCS, 1970) using a growing season of 120 and 150 days, 2) determine corn emergence and physiological maturity using 50 Growing Degree Days (GDD50) for use in adjusting the length of the growing season, 3) examine the importance of initiating the model at planting and emergence date, and 4) compare MIST modeled results to measured soil moisture data from Watermark soil moisture sensors for the 2014, 2016 and 2017 growing seasons. Currently, MIST uses a FAO crop coefficient with a growing season of 150 days, while the adjusted SCS method allows the growing season to be adjusted based on crop, variety, and maturity stages. Results showed that even though the adjusted SCS method called for irrigation earlier in the season, irrigation water was applied during the critical growth stages and did not trigger irrigation events after the crop reached physiological maturity. Results also showed that by using the adjusted SCS method and GDD50 to determine the growing season, fewer irrigation events and less total crop water use were indicated when irrigation was terminated at 2,700 and 2,900 GDD physiological maturity, depending on the variety used, as compared to the FAO crop coefficient. In addition, changing the timing of model initiation (planting vs emergence) was not important on the total crop water use, but it may have other benefits. Lastly, even though Watermark soil moisture sensors installed in the study field generally did not report similar results, especially around the mid-season, shallower sensor depth somewhat matched and showed similar trends with the MIST modeled results.
Lidar in Scaled Physical Modeling: Applications, Advantages, and Development
Year: Authors: Bell G.
Nearly every physical model done is scaled (1:1 scaled models are rare in that they require vast amounts of space and resources). The larger the scale, the larger the error is amplified from measurements at the model scale. Thus the need for a very high degree of accuracy in physical model data collection is of the highest importance. <br /><br /> When doing moveable bed modeling, it is advantageous to have data with high resolution and accuracy to evaluate bathymetric changes from hydraulic processes. Use of a lidar (light detection and ranging) system provides an accuracy of millimeters, minimizing measurement error that is magnified when scaled to prototype dimensions. Unlike the challenges of traditional bathymetric data collection methods, the high resolution of terrestrial scanning provides complete coverage of the domain. <br /><br /> Lidar scanning is a process that collects high resolution geometric, bathymetric, and topographic data. Lidar uses lasers to make measurements based on time of flight returns. The scanners used in this study each have a wavelength of ~ 1550 nm (or near infrared). These lasers cannot travel through the water medium (their energy is absorbed by the water). When the bathymetry is being scanned, the model must be drained of water (and if this is after testing, then the draining process can be long due to slow drainage in order to preserve post-test bathymetric results). These methods of collecting physical model bathymetric data have been proven to be accurate and efficient. <br /><br /> Lidar was also used in a coastal application in which a dune's response to collision and over-wash erosional events was tracked. The focus of the study whether, and to what degree, vegetation alters the dune response to those erosional events. In addition to pre and post test lidar scanning, line-scanning was performed during the testing to track the dune configuration changes during the testing. Line-scan lidar continuously scans to provide instantaneous water levels and dune evolution during each wave burst. A MATLAB code was written to filter the returns of the lidar data, thus the position of the wave (water) could be pin pointed and continuous dune topography could be collected during the model testing. <br /><br /> I am undertaking a research study which involves using lidar scanning to measure water surface elevations in scaled physical models. Currently, water surface elevation measurements are typically made using some variation of stilling gage/pipes or a variety of piezometer boards. Measurements can be made via point gage, surveyed elevation, or some other point of control. Accuracy of these measurements is on the order of 0.5 mm. The biggest constraint of using this method is the lack of measurement locations that can be utilized. The pipes will cause flow disturbance, take up space, require routing, etc. The work that I have done up to this point has proven that by scanning materials floating on the water surface, it is possible to collect accurate (below 10 mm) measurements of the water surface elevation during live physical model testing. <br /><br /> The following points summarize what will be presented in this topic. <ol><li>Explain where lidar stands now in laboratory physical modeling.</li> <li>What improvements have been done, are being done, and will be done to this data collection tool. </li> <li>Where possibilities in the future lie. </li></ol>
Assessing Groundwater Interactions between Forest and Crop Lands and the Potential to Increase Groundwater Availability through Afforestation in Mississippi
Year: Authors: Ouyang Y., Jin W., Feng G., Leininger T.D.
Groundwater depletion due to agricultural pumpage in Mississippi has been an issue of increasing water resource concern. Currently, little to no effort has been devoted to estimating the impacts and potential benefits of afforestation on marginal agricultural lands for increasing groundwater availability. In this study, we modified the USGS's MERAS (Mississippi Embayment Regional Aquifer Study) model to estimate such impacts and benefits in two different land uses at the Upper Yazoo River Watershed (UYRW) in Mississippi, one from crop land with groundwater pumpage and the other from forest land adjacent to the crop land. Three simulation scenarios were then developed for a simulation period of 147 years in this study. The first scenario was a base scenario for agricultural pumping conditions commonly used as well as natural forest conditions occurring in Mississippi. The second scenario was the same as the first scenario except that the model was iterated three times, respectively, at the increasing agricultural pumping rates of 5%, 10%, and 15% in crop land. The third scenario was the same as the first scenario except that the marginal crop land was converted to forest land a result of afforestation. These scenarios would ascertain: (1) the interactions of groundwater between the two land uses; (2) if groundwater from forest land is a source or is irrelevant to groundwater from crop land in Mississippi; and (3) the potential benefits of afforestation in marginal agricultural lands for increasing groundwater availability. Simulation results show that afforestation increased groundwater level by 3.3 ft after 27 years from 1980 to 2007 at the UYRW as a result of no groundwater pumpage in the afforested land. Our simulation further revealed that contribution of increasing groundwater recharge rate due to afforestation on groundwater availability at the UYRW was trivial. Further study is therefore warrant to estimate how afforestation of marginal crop land would enhance groundwater availability in the Lower Mississippi River Alluvial Valley.
Oxbow Lake-Wetland Systems as a Source of Recharge to the Mississippi River Valley Alluvial Aquifer
Year: Authors: Gratzer M., Davidson G., O'Reilly A.M., Rigby J.R.
This project investigates whether the Sky Lake oxbow lake-wetland system contributes significant recharge to the Mississippi River Valley Alluvial Aquifer through preferential flow pathways created by tree limbs and roots embedded in the wetland bottom sediment. The problem is being investigated by monitoring water levels in 11 wells in and around the Sky Lake oxbow lake-wetland system. These data are being used to determine the shape of the potentiometric surface and how the aquifer responds to precipitation and surface water level changes (changes in surface-water/groundwater head difference) at different locations. Temperatures at various depths in these wells are also being monitored to see how subsurface temperatures respond to air and surface-water temperature changes at different locations, thereby potentially allowing inference of different recharge sources. Soil temperatures are being measured at two locations in the wetland at 30 and 60 cm belowground and analyzed for evidence of spatial heterogeneity. Generally, the potentiometric surface is relatively flat upgradient (eastward) of the oxbow and steeper downgradient (westward) of the oxbow. It is also curved, forming a possible groundwater ridge. Hydrographs of four wells are consistent with vertical recharge beneath the lake raising the groundwater level beneath the lake. Consequently, groundwater backs up, causing a decrease in the hydraulic gradient inside and upgradient of the meander loop and an increase in the hydraulic gradient outside and downgradient of the meander loop. The hypothesis that preferential flow paths convey wetland surface water into the subsurface is supported by the temperatures recorded at 30 and 60 cm belowground, because the trends shown by these soil thermistors vary spatially.
Mississippi Private Well Characteristics and Well Owner Demographics
Year: Authors: Barrett J.R.
Mississippi citizens who acquire their drinking water from private wells do not have the luxury of knowing the quality of their drinking water on a regular basis unless they are making the effort to have their water screened and tested. Without knowing and understanding the safety of drinking water, private well owners do not know if and when treatment is needed. Approximately 90% of Mississippi citizens are served by one of the 1,200(+/-) public water systems which provide safe reliable water under the regulatory guidance of the Mississippi State Department of Health-Bureau of Public Water Supply. Private well owners are free to own, operate, and maintain their wells because there is no regulatory oversight. For some private well owners, this freedom is welcome but others want to know the quality of their drinking water and best practices for proper maintenance.<br /><br />No demographic data about private well owners has been compiled since the 1990 census. Since the inception of Mississippi State University Extension's Mississippi Well Owner Network (MWON), demographic data has been collected. The MWON workshops have allowed private well owners the opportunity to have their well water screened for bacteria. This presentation will compare demographic data of current private well owners with those from the 1990 census as well as compare to overall Mississippi demographic data. Private well characteristics are also gathered when a well owner has their water screened for bacteria. Characteristics may prove beneficial when analyzed against the presence of bacteria to assist well owners in making improved decisions on the treatment or introduction of treatment to their well water. The concluding data can be utilized to better understand and serve Mississippi private well owners.<br /><br />This study should be of interest to representatives of local municipal water systems, local communities, and rural water associations for potential expansion of their water systems. The expansion of a public water system may achieve multiple goals. Additional customers generate more revenue for the public water system, as well as provide a larger customer base in which to spread costs. The regulatory oversight of public water systems should promote and produce a safer drinking water supply for Mississippi residents. The study should also be of interest to private well owners as they navigate life obtaining their drinking water from an unregulated source.
An Analysis of the Lead Contamination Risks of Public Water Supplies in the Mississippi Delta
Year: Authors: Otts S., Janasie C.
Childhood lead poisoning is a challenging social issue that requires the coordination of health, housing, and environmental law and policy. Little is known about the contribution of lead pipes and water treatment to lead poisoning in Mississippi. In 2017, the National Sea Grant Law Center at the University of Mississippi analyzed the lead monitoring data of public water systems in nine counties as part of a Mississippi Water Resources Research Institute-funded interdisciplinary project to assess the effectiveness of community-based research strategies to analyze risk of lead contamination in public water supplies in the Mississippi Delta. The distribution system for drinking water in Mississippi is incredibly fragmented. The majority of public water systems in the region serve less than 500 customers. Due to their small size, the samples sizes required under state and federal law are quite small—usually just five or ten samples every three years. For many public water systems, this means that less than 1% of the homes within the service area are tested for lead. A review of lead monitoring data can help identify public water systems that may be experiencing problems with their corrosion control or other aspects of their systems that can increase the risk of lead contamination. However, the lead risks of individual homes throughout the community cannot be known without further testing. This presentation will present an overview of the legal framework governing the provision of public water supplies in Mississippi, followed by a summary of the research results for each county. Four public water systems reported sampling results for the current monitoring period that exceed the federal action level for lead (15 ppb). Five additional public water systems reported exceedances within the past five years. This presentation will conclude with a discussion of the challenges of addressing lead exposure from drinking water supplies and actions that policy-makers, water supply systems, community organizations, and other interested stakeholders might take to protect public health.
Evaluating the Hydrogeologic Framework of the Mississippi Alluvial Plain Using Geophysical Methods
Year: Authors: Minsley B., Kress W.H., Johnson C., Lane J.W., Bloss B., Thayer D.
A geophysical framework model of the Mississippi Alluvial Plain is being developed using a diverse suite of geophysical methods applied over multiple scales. Measurement techniques include terrestrial and waterborne continuous resistivity profiling (CRP), electrical resistivity tomography (ERT), time-domain electromagnetics (TDEM), and surface and borehole nuclear magnetic resonance (NMR). CRP methods have been used to map approximately 68 km over land and 1,200 km of streams within the study area to characterize the near-surface (<15 m) lithology of major geomorphologic units that control recharge and groundwater/surface-water exchange to the alluvial aquifer. CRP surveys have identified the boundaries of individual geomorphic features and indicate that these features have distinct ranges of resistivities. The deeper subsurface structure in the region (5-200 m) is being measured using ground-based TDEM measurements, which are capable of measuring the electrical resistivity variations within the alluvial aquifer and can be used to identify subcropping hydrogeologic units. Six east-west regional-scale profiles of time-domain electromagnetic (TDEM) measurements, each comprising 10-20 TDEM soundings and spanning 100-200 km, were conducted in the MAP study area. These profiles are approximately traverse to the synclinal axis of the Mississippi embayment. The profiles were spaced north to south at about 100 km intervals and represent a total area of nearly 100,000 sq. km. These regional-scale profiles are being used to refine the 3D aquifer structure the MAP study area and will be used to guide the survey design and planning of a large airborne electromagnetic survey of the MAP region that will begin in 2018. Borehole and surface NMR data were collected to estimate hydraulic properties and characterize subsurface hydrostratigraphy. NMR methods are used to measure hydraulic properties in the formation including total-, mobile-, and bound-water content, estimates of pore-size distribution, and hydraulic conductivity with depth. The interpreted hydrostratigraphic layers from the surface NMR measurements were consistent with the presence and thickness of a confining unit overlying a more coarse-grained aquifer and were validated by observations from nearby boreholes and TEM surveys. The goal of the comparison is to establish a relation between resistivity and NMR results and facilitate development of a petrophysical relationship between the resistivity and hydraulic conductivity. Resistivity values may then be used as a cost-effective way approximate aquifer hydraulic conductivity distributions that will be input into regional groundwater models.
Improving Estimates of Recharge in the Mississippi Alluvial Plain Using the Soil-Water-Balance (SWB) Model
Year: Authors: Westenbroek S., Ladd D.
Independently derived estimates of recharge calculated from spatially explicit inputs can significantly improve evaluations of groundwater movement. The U.S. Geological Survey's Soil-Water-Balance (SWB) code is a tool to estimate distribution and timing of net infiltration (recharge) out of the root zone using readily available data, such as gridded climate, land-use, and soils. Calculations are completed on a daily time step and gridded results are summarized on monthly and annual time scales. In addition, irrigation water requirements (crop water demand) are optionally estimated to evaluate the effects of agricultural water use on the water budget. Version 2.0 of the SWB code was recently released and is being applied to the Mississippi Alluvial Plain (MAP) study area. Current work combines historical and recent land use, agricultural, and daily weather data to produce estimates of crop water demand and net infiltration at a 1-km grid resolution. Previous modeling in the study area assumed some fraction of precipitation (on the order of 1.0E-4 to 7.0E-2) becomes recharge, supplied to the model through 19 zones of similar soil type and geomorphology. The SWB approach allows recharge to be estimated with greater spatial resolution than the original zone method, but the limited knowledge of crop patterns from the early 20th century introduces uncertainty to SWB estimates from that time period. SWB recharge estimates will be constrained by other complementary datasets generated for this project, such as the Empirical Water Budget model. Our initial work generates recharge values up to an order of magnitude greater than the previous model estimates in some locations, particularly relative to the initial estimates based on data from early in the 20th century.
Evaluation of Methods for Relating Continuous Streambed Resistivity Data and Hydraulic Conductivity in the Mississippi Delta
Year: Authors: Killian C., Rigby J.R., Barlow J., Kress W.H., Schmitz D.
Data worth and uncertainty analyses of an existing regional groundwater-flow model that includes portions of the Mississippi Alluvial Plain (MAP) identified streambed hydraulic conductivity as a notable parameter that affected model uncertainty, influencing the model's ability to evaluate groundwater and surface-water interactions. The streambed hydraulic conductivity of each stream reach is currently represented by one value in the existing model due to the paucity of existing data, resulting in high uncertainty in model outputs. Waterborne continuous resistivity profiling (CRP) data was collected by the U.S. Geological Survey in 2016 and 2017 along selected streams within the Mississippi Delta to: (1) characterize near-surface lithology of the Mississippi River Valley alluvial aquifer for improved understanding of groundwater and surface-water interactions; and, (2) allow for increased variability of streambed hydraulic conductivity within the existing model. Multiple methods to translate resistivity values to estimates of streambed hydraulic conductivity were evaluated. Two-dimensional profiles of estimated streambed hydraulic conductivity data were aggregated vertically to develop one-dimensional streambed hydraulic conductivity values and horizontally to the scale of the existing model. Estimated streambed hydraulic conductivity values from the methods were incorporated into the existing model and model estimates of predicted streamflow and groundwater levels were compared to measured values to evaluate model performance for each translation method. This exercise to improve streambed hydraulic conductivity values will allow for reduction in model uncertainty by allowing the model to better estimate groundwater/surface-water interaction and improve tools to make informed decisions when creating and implementing best water-use management practices.
Coupling Groundwater Flow Modeling with Geophysical Mapping and Hydrologic Monitoring to Assess Water Availability in the Mississippi Alluvial Plain
Year: Authors: Kress W.H., Barlow J., Hunt R.J., Pindilli E.J.
The Mississippi Alluvial Plain water availability project is in it its third year of data collection and model development in support of a water availability and valuation decision support tool for the region. Years 1 and 2 of the project focused on assessing existing datasets and groundwater- flow models to help increase efficiency of geophysical mapping efforts and hydrologic monitoring networks. These field data, in turn, will help improve the next generation groundwater- flow model. This third year focuses on the development of a series of supporting models and automated data services designed to update the groundwater-flow model on regular intervals. A range of approaches is targeted, including water budget models to estimate recharge, surface-water model to supply baseflow estimates, irrigation water-use model to provide estimated pumping rates, and a geophysical model to inform the hydrogeologic framework. Stakeholder forecasts from the updated groundwater-flow model are improved as uncertainty decreases. By coupling the modeling, mapping, and monitoring within an iterative framework, an improved representation of alluvial aquifer water resources will be developed. The final outcome of this work is an encompassing economic-physical system approach that allows stakeholders to assess societal and system costs and benefits associated with water use from the MAP aquifer. The economic analysis will incorporate both supply (e.g., how a reduction in groundwater availability might affect agricultural revenue) and demand-side effects (i.e., how people's behavior, such as crop switching, might influence the other parts of the system).The economic-physical system approach forms the basis of a decision support system, where economic and physical system analyses will provide the basis for informed cost-benefit trade-offs in the region.
Study of Sediment and Nutrients in Pelahatchie Bay and Upland Mill-Pelahatchie Creek- Watershed
Year: Authors: Chao X., Bingner R.L., Zhang Y., Yasarer L., Jia Y.
Ross Barnett Reservoir is the largest drinking water source in the state of Mississippi. Pelahatchie Bay is a part of Ross Barnett Reservoir, and located in the southeast corner of the reservoir. The upland watershed of Pelahatchie Bay contains a high percentage of construction sites and developed area, causing a lot of sediment and associated pollutants to discharge into the bay through runoff. In addition, sediment, nutrients, and other pollutants may also flow into Pelahatchie Bay from the upstream Pelahatchie Creek. <br /><br /> The major water quality problem in Pelahatchie Bay is sedimentation, which causes high turbidity and limits boat navigation in the bay. The levels of nitrogen and phosphorus in the bay are relatively high and cause excessive growth of aquatic plants. <br /><br /> In this study, the AnnAGNPS watershed management model, developed at the USDA ARS, National Sedimentation Laboratory (NSL), are applied to simulate the loads of runoff, sediment and nutrients from the upland watershed. The simulated results are used as boundary conditions for CCHE, a free surface flow, sediment and water quality model developed at the National Center for Computational Hydroscience and Engineering (NCCHE), to simulate the flow, sediment transport and water quality processes in the Pelahatchie Bay. The concentration distributions of sediment and nutrients, and their variations in time due to the influence of loading, wind, and the operation of the Ross Barnett Reservoir are simulated. <br /><br /> This study provides a useful tool to evaluate the effectiveness of watershed BMPs on water quality in Pelahatchie Bay. Information obtained from the research can be used by decision makers to develop improved watershed management plans to achieve maximum water quality benefits to Pelahatchie Bay.
A Project Based Learning Study Oriented to Develop a Natural Stream Restoration Design
Year: Authors: Ramirez-Avila J.J., Delgado T., Buie T., Schauwecker T., Martin J.L., Ortega-Achury S.L., Czarnecki J.
The Natural Channel Design (NCD) approach to stream restoration was developed to reproduce the function of natural streams. Headwater tributaries of Catalpa Creek in Mississippi are on an urban fringe and have been experiencing impacts of progressive development over the last decade. The runoff depth and peak flows from stormflow events have increased, inducing incision and streambank erosion. A project-based learning study involving senior and graduate Civil and Environmental Engineering students was developed to determine the hydrologic, hydraulic and geomorphologic functions of different reaches along three tributaries of Catalpa Creek and propose a stream restoration design following the NCD approach. The design considered restoring floodplain connectivity, increasing sinuosity and reducing active erosion. The goal and specific objectives of the study were addressed combining field reconnaissance and detailed data collection, laboratory analysis and computational modeling techniques. Hydraulic, hydrologic and geomorphologic data were collected and analyzed including channel and floodplain survey, flow depth and velocity at different stages, sediment loads, and streambank material. Hydrologic assessments were completed using GIS applications and the HEC-HMS model. The HEC-RAS model was used to assess existing stream conditions and to test the effectiveness of the proposed restoration design, which will include in-stream structures to decrease potential effects of near bank shear. The presentation will detail the characteristics of the proposed restoration design and the learning outcomes from the based learning project.
Impacts of Riparian Buffer Zones on Stream Water Quality: A Quantitative Assessment in the Catalpa Creek Watershed
Year: Authors: Ramirez-Avila J.J., Grafe J., Schauwecker T., Ortega-Achury S.L., Martin J.L., Noble T., Czarnecki J.
Riparian buffer zones importantly affect stream water quality and its ecosystem's structure and function. A study was conducted to determine if there is a measurable difference in water quality conditions between forested or grassed riparian zones along tributaries of the Catalpa Creek Watershed. The study considered field data and laboratory analysis. Weekly monitoring was performed at 18 stations along the tributaries during fall 2017. The study reaches consisted of an upstream segment covered by a forested riparian zone and a downstream segment in which grass grew and was mowed along both sides of the stream. Stream water temperature along the forested riparian segments were lower (13.9°C to 27°C) than those along the grassed riparian zones (15.0°C to 31.5°C). The differences in water temperature between forested and grassed riparian zones were smaller as the air temperature decreased during the late fall season. Overall, the instantaneous concentration of dissolved oxygen (DO) along the reaches was always higher than 6 mg l<sup>-1</sup>, a higher concentration than the standard proposed by MDEQ (5.0 mg l<sup>-1</sup>). The DO concentration along the stream was sometimes higher for grassed riparian zones, which can be attributed to reaeration caused by an abrupt change in slope, depth and flow velocity downstream of the forested riparian zone. However, DO concentrations at the end of the grassed riparian segments reached similar or lower values than those observed along the forested riparian segment. No adverse impacts on water quality were caused on the monitored reaches due to levels and temporal or spatial variability of pH in the stream water. The spatial variability of pH appears to be consistent with the spatial variability of DO concentrations for all the studied reaches. Forested riparian zones can reduce stream water temperatures and maintain favorable DO concentrations and pH, with a biological significance for living organisms in the stream. Consequently, establishment and maintenance of forested riparian zones might provide benefits in mitigating adverse impacts on stream ecology and water quality.
Adopting Ecosystem Services for Enhanced Sustainable Communities by Wetlands Assimilation of Wastewater and Water Quality Credit Trading
Year: Authors: Ko J.
Adopting ecosystem services as policy tools in achiving sustainable communities have been advocated by academicians and government officials. Adopting natural ecosystem services increases local community's capacity to comply with environmental regulations (e.g., Clean Water Act) without significant financial burden, while keeping ecological integrity of natural ecosystem surrounding human community. For example, more than half of communities in State of Mississippi has been failing in compliance of wastewater treatment permit, because they are in economically depressed region, causing harms to the human health, and the aquatic ecosystems. Natural wetland assimilation of municipal wastewater increases water quality of wastewater, contributing to increased compliance of wastewater permit with highly reduced engineering and operating costs, and increased vegetative productivity. Water quality credit trading - another policy tool of adopting ecosystem services - is an EPA approved policy which allows credit trading between polluters and local stakeholders of unimpaired watershed on nutrients (e.g., total nitrogen) and sediments. After considering that State of Mississippi is economically poor and a rural state, adopting ecosystem services has significant potentials of increasing compliances of environmental regulation with less financial burden, and generating additional financial revenues to local communities. However, currently the two policy tools are not available in the State of Mississippi, even though the EPA endorses them. The presentation discusses the opportunities of introducing the two ideas to Mississippi.
Reducing Uncertainty in Estimates of Irrigation Water-Use
Year: Authors: Westerman D., Wilson J., Painter J., Torak L.
The Mississippi Alluvial Plain (MAP) is one of the most important agricultural regions in the United States, and the MAP region has seen substantial declines in groundwater levels and reductions in stream base flow that have led to concerns about sustainability and future availability of the water resources. One of the tools used to understand groundwater responses in the MAP region to current and future water-use demands is groundwater modeling; however, one of the largest sources of uncertainty in groundwater modeling of the MAP region is irrigation water-use estimates. The U.S. Geological Survey (USGS) is working closely with local and state cooperators to help improve estimates of water-use demand within the MAP region. A publicly available water-use network is being established that includes 46 real-time monitoring flow meters installed on irrigation wells. In addition to the real-time data, existing State programs will be leveraged to obtain water-use measurements from hundreds of additional metered sites within the MAP region. The metered water-use data will be essential in providing authoritative datasets for estimating water-use demands based on crop types, climatic variables, and the variety of soil types present within the MAP region. Using the water-use metered data as the main driver, the USGS is developing a national water-use model with the goal of estimating monthly groundwater use for irrigation at a spatial resolution of 1 kilometer. The initial version of the water-use model will be aimed at quantifying irrigated acres, estimating irrigation rates developed from current water-use metered data, and developing estimates of water use for the entire MAP region. Future, more sophisticated versions of the water-use model will aim to incorporate additional site-specific water-use data, develop irrigation rates as a function of climate variation based on the metered data, use remote-sensing data to estimate irrigated acres, and implement geostatistical and machine-learning approaches to spatially and temporally estimate groundwater use for irrigation. The real-time flow meter data collected as part of this project, when coupled with real-time remote sensing data, will allow for real-time prediction of water use. Estimates from the water-use model will be used directly as input into the current groundwater-flow model, which will help guide future refinement of both the water-use and groundwater models, capture uncertainties in the data, and identify data gaps.
Improving Numerical Simulation of Streams and Shallow Groundwater in the Mississippi Alluvial Plain
Year: Authors: Leaf A., Breaker B., Adams R., Dietsch B.
In humid regions such as the Mississippi Alluvial Plain (MAP), surface water typically exerts a fundamental control on both the water levels and flow directions of shallow groundwater. Groundwater pumping ultimately diverts water that would otherwise go to streams or lakes, and can have dramatically alter surface water features, even when only a small portion of the overall regional water budget is removed compared to recharge. The stream network in the MAP is an important source of water to wells thus serves as an important consideration for sustainable management of groundwater.<br /><br /> Representation of streams in groundwater models has historically been arduous and error-prone, requiring many GIS operations or even hand-digitizing of features. Software support for automation of stream network creation and visualization has been limited. Automated stream network generation in the MAP region is challenging in that it encompasses a large number of streams, many of which originate far from the area of interest, has a complex history landscape alteration, and highly variable surficial lithology. In the MAP area, three new approaches are being performed to improve the simulation of this important surface water network. <br /><br /> 1) Automation, machine learning and additional field data collection are being used to improve the representation of streams in the Mississippi Embayment Regional Aquifer System (MERAS) model. Python code was developed to automatically translate information from the NHDPlus version 2 database into finite-difference stream networks. The revised networks include most streams that have base flow for at least part of the year, increasing the number of streams represented in the MERAS model from 43 to more than 5,000. The automated processes of generating the stream networks facilitates adaptation to different computational grids or inset areas within the larger Mississippi Embayment. <br /><br /> 2) A random forest (RF) statistical model was developed to estimate streamflows originating outside of the MERAS study area as well as ungaged flows in both space and time within the model domain. The RF model considers drainage area, climate statistics, and other factors to estimate stream flows at monthly intervals, providing valuable information on stream inflows to the model because continuous flow observations that can be compared to output from the physics-based finite difference model. <br /><br /> 3) Waterborne geophysical electrical resistivity surveys were conducted on more than 700 miles of streams, to identify areas of relatively high and low permeability in the streambed sediments, and inform the representation of streambed conductance in the model. Simulated streamflows will be compared to existing and newly collected measurements of base
Updates to a Groundwater Flow Model to Facilitate Decision Support and Uncertainty Analysis for the Mississippi Alluvial Plain
Year: Authors: Peterson S.M., Fienen M.N., Clark B.R., White J.
A recently-updated groundwater model of the Mississippi Embayment has previously provided key information and decision support for stakeholders and serves as the foundation for the Mississippi Alluvial Plain project for continued decision support tool development. The MODFLOW-2005 groundwater model was updated to use the Newton-Raphson solver, which provided an improved ability to simulate the nonlinear unconfined aquifer. The streamflow routing network was updated with a more detailed and comprehensive representation of surface water features. Recharge was updated using outputs from a Soil-Water-Balance model generated through a companion study. The MODFLOW-2005 model also was converted to MODFLOW-6 to take advantage of the most-current (2018) software improvements available and to facilitate future refinement. Existing calibration targets were retained with the exception of stream base flow, which also was updated through a companion study. Forecast uncertainty for stakeholder-identified scenarios is being evaluated through history matching and uncertainty analysis using PEST and a newly developed iterative ensemble smoother. <br /><br /> In addition, the value of potential future data is assessed through using the updated model to quantify their role in reducing uncertainty of stakeholder-identified forecasts. This type of analysis, known as "data worth" analysis, is being used to prioritize geophysical mapping and hydrogeologic monitoring efforts so that the data collected is most valuable to model-simulated future conditions. Such analyses can be repeated as necessary as new societal concerns arise and as new understanding of the MAP system is gained.
Riverbank Filtration, Transfer, and Injection Pilot Project along the Tallahatchie River for Enhanced Aquifer Recharge: Progress and Plans
Year: Authors: Rigby J.R., Ozeren Y., Holt B., Pophet N.
The USDA-ARS is conducting a pilot study to investigate the potential for using aquifer storage and recovery technology to augment recharge to the Mississippi River Valley Alluvial Aquifer (MRVAA). This study proposes to use riverbank filtration to capture water from the Tallahatchie River for direct injection in the aquifer. Preliminary investigations of interaction between the river and the aquifer were conducted near Money, MS including continuous resistivity profiling of the subsurface, bathymetric characterization of the river channel and a pumping test to analyze drawdown and recovery of groundwater levels at fifteen observation wells up to 300 meters from the river. The pilot study will combine an extraction well along the Tallahatchie River with a transfer pipeline approximately 2 miles long to a set of injection wells west of the river. Locations have been chosen for the pilot study and a design is being developed. This presentation will review the conceptual model of the pilot study, results from investigations at Money, MS, and the timeline for the pilot study construction and operation.
Safety of Flood Control Dams in Mississippi
Year: Authors: Cummings A.
In the 1960's and 1970's, the USDA Soil Conservation Service (now the Natural Resource Conservation Service [NRCS]) constructed hundreds of earthen dams throughout the State. These dams were constructed primarily for flood control purposes under the directives of PL-534 and PL-566. They were designed and built using federal funding and were locally sponsored by county or local drainage districts. As part of the agreement the drainage districts accepted the responsibility for the maintenance and operation of the dams. Unfortunately, many of the drainage districts are no longer functioning, or are not functioning as intended. Nearly all of these dams have maintenance issues (some serious), but without a functioning drainage district to hold accountable, correcting these issues is a challenge. The MDEQ Dam Safety Division has been working with the NRCS, the Mississippi Soil and Water Conservation Commission (MSWCC), local governments, and landowners to try to bring these dams into compliance with State regulations and prevent dam failures. This presentation will discuss the status of these dams as well as previous and future efforts planned to try and improve the condition and safety of these dams.<br /><br /><a href="/conference/pdf/andrew_cummings2018.pdf">Download the presentation</a>
Water Use in Mississippi
Year: Authors: Fitzgerald C.A.
The Office of Land and Water Resources (OLWR) is responsible for the management of the water resources in Mississippi. Mississippi code requires that "the water resources of the state be put to beneficial use to the fullest extent of which they are capable, that the waste or unreasonable use, or unreasonable method of use, of water be prevented, that the conservation of such water be exercised" This is achieved through the water withdrawal permitting process which is informed by the inventorying and assessment of the availability of water associated with fresh water aquifers and major fresh water streams in Mississippi and through the evaluation of water use as reported to MDEQ. Programs for reporting how much of the State's water is used and how it is used are in place for agriculture, industry, public supply, private and commercial areas. These programs provide the OLWR with information needed to assess future permitted water use parameters, whether current conservation methods are effective, as well as allow the OLWR to develop plans to better manage the State of Mississippi's water use for future generations.<br /><br /><a href="/conference/pdf/casey_fitzgerald2018.pdf">Download the presentation</a>
Water Resources Data Management
Year: Authors: Hawkins C.
The Office of Land and Water Resources (OLWR) is responsible for the management of the water resources in Mississippi. In order to accomplish this, the OLWR collects and maintains a significant amount of data. This data includes groundwater and surface water withdrawal permit information, such as landowner and permittee contact information, groundwater well construction data, beneficial uses, permitted volumes, locations, etc. It also includes water quantity data, water quality data, compliance and enforcement actions, and other pertinent information associated with the states aquifer systems and streams. Most of this information has been maintained in the OLWR's current database the Water Resources Information Management System (WRIMS) for over 15 years, while other data either existed on spreadsheets or paper files. OLWR is developing a new database that not only will house all the information being maintained in WRIMS but would also incorporate other datasets needed to manage the state's water resources. The new database will also serve as a tool for processing surface water and groundwater withdrawal permit applications. The first phase of this web-based database will be in production this spring with other phases to follow over the next two years. This upgrade will be a vast improvement over the aging WRIMS database and help in making informed decisions associated with Mississippi's water resources.<br /><br /><a href="/conference/pdf/chris_hawkins2018.pdf">Download the presentation</a>
Water Resources Data Availability
Year: Authors: Phillips P., Watts J.
A primary objective of the Mississippi Department of Environmental Quality (MDEQ), Office of Land and Water Resources (OLWR) is to research and manage the water resources of the state to assure adequate supplies for the future, which requires a significant amount of data and information, much of which is easily available to the public. OLWR maintains geographical information system (GIS) data sets, attribute data, and links to related data. GIS data sets include groundwater wells, surface water diversions, public water supply wells and their protection areas, and dams across the state with the associated data for each record. The Water Resources Information System (WRIMS) includes data such as the owner, well construction information, beneficial use, water levels, water quality information, groundwater and surface water permit information, and surface water discharge measurements. Selected data from WRIMS is the source of attribute data for some of our GIS data sets. OLWR also tracks water use for selected wells. Public water supply wells in the Source Water Assessment Program can be viewed online via a web map. This web map includes data about potential contaminants provided by OLWR as well as other sources such as MDEQ's Office of Pollution Control and the Environmental Protection Agency. OLWR's Dam Safety Division also maintains a web map that allows viewing of dams, inundation areas from simple breach analyses, and these data's associated attributes. Along with data, OLWR provides information on its various programs, forms, permit applications, well completion reports, and water well drillers' licensing. OLWR also provides links to outside source data such as the Office of Geology's geophysical logs, the Yazoo Mississippi Delta Joint Water Management District's water permit data, and water compendium that includes GIS data from MDEQ's various water related programs.
Non-negative Matrix Factorization Based Feature Analysis for Hyperspectral Imagery of Sediment-Laden Riverine Flow
Year: Authors: Scott N.V., Moore I.C.
Nonnegative matrix factorization based feature selection analysis performed on land-based hyperspectral imagery of the Mississippi river identifies 10 spectral bands in the visible and near infrared portion of the electromagnetic spectrum that are significant contributors to the resulting structural image clustering of sediment-laden water. Various distance metrics including the Kullback-Liebler divergence, the Bhattacharyya distance, the Fisher discriminant ratio, and the between class/within class scatter matrix, provide clear evidence for the potency of these spectral bands for class separation of turbid, sediment-laden water from clear water provided that the data contains low noise. In addition, spectral feature ranking of spectral band subsets from the identified characteristic spectral bands allows insight into the relative importance of different reduced dimension spectral band subgroups for clear water versus sediment-laden water characterization. The results support present day multispectral satellite design methods for land-water imagery where payload power resources are relegated to certain spectral bands at the expense of others.
Aquatic Vegetation Management to Enhance Multiple-User Benefits of Southeastern Wetlands
Year: Authors: Ervin G.N., Turnage G.
Resource managers of public lands, such as national wildlife refuges, are tasked with meeting multiple use needs of the fish and wildlife that reside on these lands, as well as the people who utilize those lands for recreational activities such as fishing, boating, and wildlife watching. Biologists at the Sam D. Hamilton Noxubee National Wildlife Refuge (NNWR) have identified the dominance of certain problematic aquatic plants as a key obstacle to achieving these multiple use needs in lakes and associated wetlands on this and other southeastern wildlife refuges. Few methods are currently known that allow the control of some of the problematic aquatic plant species that they encounter, while simultaneously enhancing the diversity of desirable species, maintaining water quality, and providing diverse aquatic habitats that are needed for many species of wildlife and for human users of these facilities.<br /><br /> The work we have initiated is aimed at determining optimally effective methods of managing invasive and problematic aquatic plants to enhance wetland plant diversity in a way that improves the quality of wetlands as wildlife habitat and sources of recreational use, while also minimizing potential negative impacts on water quality and desirable native plant species. This research will explore a variety of chemical control measures (herbicides) to reduce the abundance of key nuisance plant species, while maintaining diversity of desirable species and also minimizing any negative impacts on key water quality parameters (e.g., dissolved oxygen, nitrogen, and phosphorus).
Evapotranspiration Measurement Using Eddy Covariance Systems for Irrigation Scheduling
Year: Authors: Sui R., Anapalli S., Baggard J., Murrell C.
Irrigation plays a critical role in crop production. Irrigated crops produced more and stable yields than dryland crops. In the Mississippi Delta, acreage of irrigated land has increased rapidly in recent years. Uncertainty in the amount and timing of precipitation has become one of the most serious risks to crop production in this region. Crop producers have become increasingly reliant on irrigation to ensure adequate yields. Excessive withdrawal of the groundwater resulted in water level decline in the Mississippi River Valley Alluvial Aquifer. Ongoing depletion and stagnant recharging of the aquifer jeopardize the long-term availability of the aquifer and place irrigated agriculture in the region on an unsustainable path. Novel irrigation techniques and tools are needed for improving water use efficiency to maintain Mississippi water resource sustainability. Eddy covariance (EC) method is capable of measuring exchanges of water vapor between the surface of the earth and the atmosphere, and have been used for monitoring agroecosystems and measuring crop evapotranspiration (ET) for irrigation scheduling. Objectives of this project were to use EC systems to monitor the agroecosystem and measure evapotranspiration in Mississippi Delta for water management research and agroecosystem assessment. Five EC systems were set up in the Mississippi Delta for ET measurement and agroecosystem monitoring. Three of them are located in Stoneville, MS and two others in Arcola, MS. The EC system consisted of a CH<sub>4</sub> analyzer for measuring methane gas flux, CO<sub>2</sub>/H<sub>2</sub>O analyzer for measuring carbon dioxide and water vapor fluxes, three-dimensional sonic anemometer for determining wind speed in three dimensions, and biomet (biological & meteorological) sensors to collect ancillary data for filling measurement gaps and interpreting flux results. Installation and preliminary field tests of the EC systems have been completed in 2016. These systems are being used to collect data in 2017 season. This presentation will report the ET measurement results with corn, soybean, and cotton in different locations in Mississippi Delta.
A Spatial Decision Support System for Choice and Placement of Nitrogen Source Reducing Best Management Practices in the Beasley Lake Watershed, Delta
Year: Authors: Sinshaw T.A., Surbeck C.Q., Shields D., Hossain A.
Nutrient reduction efforts are planned based on spatially complex watershed information. These efforts encompass a series of activities, such as identifying sources, quantifying source yields, estimating exported load, and establishing source reducing best management practices (BMPs). The choice and placement of BMPs requires a decision on three conflicting objectives: performance, site suitability, and establishment cost.<br /><br />The present study applied a spatial decision support system for the Beasley Lake Watershed to optimize a nitrogen (N) source reduction plan. The watershed information required to assess N pollution was stored as a database pool and served as an updatable data view. The nutrient movement on the landscape was tracked from sources to the receiving Beasley Lake using a distance-decay method. The critical N source locations and suitable sites for establishing buffer strips and wetlands were identified. This information served as a decision guide for choice and placement of BMPs within the watershed. Three BMP scenarios were identified through an iterative BMP placement process. With these BMP scenarios, it was possible to reduce up to 25% of the N load. The best BMP scenario was found at a cost to performance ratio of 168 $/kg. The approach presented in this study can be an alternative N assessment method when the availability of data and resources limit the use of existing watershed models for water quality assessment.
Informing Environmental Health through Community-Engaged Research: Testing for Lead in Drinking Water in the Mississippi Delta
Year: Authors: Green J.J., Fratesi M.A., Woo L., Willett K., Thornton C., Avula B., Khan I., Otts S.
A variety of frameworks—including community based, participatory, action-oriented, and citizen science research—are being increasingly recognized as helping to engage community members with understanding and improving environmental health. Potential exposure to lead through drinking water is one among many important issues warranting this type of work. This poster will provide an introduction to community engaged research and then describe an interdisciplinary program connecting the University of Mississippi (UM) with community organizations in the Delta region of the state to test for lead. Working through an interdisciplinary collaborative consisting of the UM National Sea Grant Law Center, School of Pharmacy Division of Environmental Toxicology, and Center for Population Studies, researchers have partnered with nonprofit organization, community health centers, and Mississippi State University Extension to conduct outreach, education, and research with residents from across a nine-county region. This includes participants completing household surveys and submitting drinking water samples. Beyond providing results and recommendations back to individual households and populating a novel dataset, the data are being integrated with publicly available demographic, socioeconomic, and housing data to help inform recommended strategies for additional targeted water testing. Illustrative findings will be shared through the poster, emphasizing the associations between individual and aggregate housing characteristics, thereby demonstrating the importance of community engaged approaches to environmental health research.
What Are the Precursors to Watershed Civic Engagement: Can Grass Roots Environmental Organizations Be Grown?
Year: Authors: Ziogas I., Cossman R.E., Ingram R.
If one is to create and partner with a grass roots organization where there is none, what are the precursors to civic engagement? This project identifies the necessary and sufficient conditions of civic engagement, particularly as it relates to environmental stewardship. Specifically, we are revealing the parameters surrounding the organic emergence of grassroots environmental groups. We are also interested in their financial viability and organizational longevity given conditions of minimal exogenous intervention and/or support by formal instruments of environmental governance. The set of hypotheses we introduce hinges on the appearance of an immediate perceived threat, coupled with the presence of high individual capacity for action in the context of a well-connected, quasi-informed, community. Our model incorporates insights from the wider civic engagement literature and is tested against new primary data. Our initial findings strongly support our claims. As we demonstrate, the likelihood of civilian involvement in regards to environmental action is contingent on the magnitude of the perceived source of degradation, the size of affected communities, and the socioeconomic capacity of those communities to engage the problem. However, it should be noted that even under those specified conditions, organizational success is not guaranteed and is not always correlated with organizational longevity; contradicting expectations, we find that when an environmental group rapidly manages to achieve its immediate goals, it tends to fade and decay, perhaps due to the lack of incentives for its continuing presence.
Controlling Mechanism of Chlorination on Emitter Bio-clogging for Drip Irrigation Using Reclaimed Water
Year: Authors: Song P., Li Y., Feng G.
Emitter clogging has been one of the bottlenecks restricting the drip irrigation application and promotion. Drip irrigation using reclaimed water or polluted surface water may causes the greater risk of bio-clogging, which is the most typical and complex clogging type. With the strong oxidizing effect, chlorination has been considered as the most effective method of controlling emitter bio-clogging. However, its mechanism is still unclear. Meanwhile, there were no unified standards established for chlorination to refer to. Field experiment using reclaimed water treated with Cyclic Activated Sludge System (CASS) process was carried out in the sewage treatment plant, in order to study the controlling mechanism and impacts on emitter bio-clogging with three types of chlorination modes. The results showed that the chemical chlorination could effectively regulate the microbial growth in the emitter clogging substances, with the microbial Phospholipid Fatty Acid (PLFAs) decreased by 8-36%, and the microbial types reduced by 2-3, and the microbial activity decreased by 3-23%, and the secretion of sticky Extracellular polymeric substances (EPS) decreased by 20-43%. The bio-clogging substances were well controlled, and the contents of solid particles (SD) decreased by 5-48%, while the discharge ratio variation (Dra) and Christiansen uniformity coefficient (CU) were improved by 15-23% and 7-20% respectively. However, the effects of different chlorination modes varied significantly, the chemical chlorination with low concentration and long contacting duration (2.5mg/L+2h) was recommended to control bio-clogging in the drip irrigation system using reclaimed water treated with CASS process.
A Preliminary Investigation of Feral Hog Impacts on Water Quality
Year: Authors: Chaney B., Brooks J.P., Aldridge C., Omer A.R., Street G.M., Baker B.H.
Feral hogs (<em>Sus scrofa</em>) are world renowned for having disruptive behaviors that can negatively affect the environment around them. This study was conducted at Mississippi State University South Farm Research Facility. The objective of this preliminary investigation was to identify how water quality and nutrient distribution was affected by the presence of feral hogs. The experiment involved analyzing the nutrients along with the microbial organisms that were present before and after storm event runoff within in-ground sampling units that were located above and below the hog enclosure. Throughout sampling periods at field locations, samples were separated into two individual sampling containers; one set of samples were sent to the USDA lab for microbial testing and the remaining samples were filtered and preserved in the water quality lab at Mississippi State University for nutrient analysis testing. According to the sample analysis, nutrient concentrations and bacterial abundances fluctuated throughout the sampling period. However, nutrient concentrations and bacterial abundances seemed equally or less variable after January 2017 in the upstream and downstream locations. Despite limited sample size availability and detection effectiveness, findings such as these will help guide researchers in discussions pertaining to water quality viability and will allow for future analysis in similar studies involving the presence of feral hogs and their correlation to water quality.
Impact of Different Ratios of Surface Water and Groundwater for Row Crops Irrigation on Groundwater Level in Mississippi Delta
Year: Authors: Gao F., Feng G., Dash P., Ouyang Y.
Groundwater resources in Mississippi Delta have been overexploited for agricultural irrigation for a number of years. Over 700,000 hectares of row crops in this region was irrigated by using groundwater. As a result, groundwater level has declined > 6.5 m (20 ft) since 1970, which threaten the sustainability of irrigated agriculture in this region especially in Big Sunflower River Watershed. Surface water resources can be used as an alternative source for irrigation. Limited information was reported regarding groundwater level as affected by different ratios of surface water and groundwater for irrigation in this region. The objectives of this study were to employ a coupled SWAT-MODFLOW model and simulate the change in groundwater level and storage as affected by a) no irrigation scheme; b) conventional irrigation scheme; c) water-saving irrigation scheduling by using different percentages of surface and ground water. An analysis from 2000 to 2016 showed practically achievable reductions in weekly pumping (<22%) and replacement by surface water for irrigation would stabilize the groundwater levels in the Mississippi Delta. This study suggested that the conjunctive use of surface water in addition to groundwater can be a sustainable way for future to continuously grow major row crops soybean, corn, cotton and rice in the Mississippi Delta.
Salinity Effects from Treated Effluent as Irrigation
Year: Authors: Brock M., Tagert M.L.
Around the world, increasing and sometimes competing demands on water for irrigation, industrial processes, aquifer recharge, drinking and other systems require investigation into additional viable water sources. Effluent from industrial and municipal wastewater treatment systems is gaining more attention as a potential source to meet these demands. By receiving further treatment beyond these systems, reclaimed or recycled water has been developed as a means to use this effluent as a viable source. Southwest Florida has proven its successful use on a large scale for more than 40 years with 62 treatment facilities and widespread applications without harmful impacts on local water and soil quality (Reclaimed Water, 2014). Risk factors that must be addressed include pathogens, nutrients, and salinity. While standard treatment facilities meet established limits for these components, reclaimed water requires extra treatment in potential applications that have more direct contact with humans. Salinity is considered one of the greatest risk factors associated with irrigation applications as it affects hydraulic conductivity of soils and water uptake of plants. This study assesses salinity in wastewater effluent and examines its potential for irrigation. A potential solution combines effluent with other water sources to reduce salinity risks to soil. Using samples from Starkville Wastewater Plant, electrical conductivity and total dissolved solids of the effluent are tested and compared to values established by the Food and Agriculture Organization as water quality restrictions to irrigation (US EPA, 2012). Using these restrictions, effluent is diluted using a predetermined ratio with controls set as undiluted effluent and freshwater. Results will provide a basis for potential application of treated water for irrigation in Mississippi or demonstrate a need for additional treatment of wastewater to meet standards adopted by current reclaimed water facilities.
Ecological Agriculture Application with Winter Flooding
Year: Authors: Firth A., Baker B., Brooks J.
Rice is the staple food for more than half of the world's population and has the ability to support more people per unit of land area than wheat or corn, as rice produces more food energy and protein per hectare than other grain crops. However, with the human population projected to reach 8.5 billion by 2030, there are major concerns about the sustainability of rice production practices because of its major contribution to water pollution and soil degradation. Thus, there is a need to identify sustainable production practices that minimize environmental damage, while also remain economically feasible. This study investigated a potentially sustainable rice production system in the Mississippi Alluvial Valley (MAV) that uses ecological principles to enhance environmental quality and economic gain at the field scale. It was hypothesized that the annual flooding of rice fields to create water bird habitat would benefit soil health, and in turn water runoff, providing agronomic benefits to the farmer. Two sites were selected that applied different management regimes during the winter: conventional fallow fields and winter flooding. Soil microbial diversity and nutrient content were quantified and compared for a measure of overall soil health. Results of the project will provide valuable data that identifies the relationships between biodiversity, soil health and water quality. Proof of concept at the field scale will provide a framework for other producers within the MAV to adopt similar management methods, ultimately improving the overall integrity of soil, water, and environmental quality as well as the farmer lifestyle.
Effects of Prescribed Burning on Canopy Structure and Water Partitioning in an Upland Oak Forest
Year: Authors: Drotar N., Siegert C., Alexander H., Varner J.M.
The distribution of rainwater by the forest canopy into stemflow (SF), throughfall (TF), and interception (IN) is determined by tree species characteristics, (canopy storage capacity, bark roughness, bark water storage, and bark thickness) as well as canopy position (midstory vs. overstory). In upland oak ecosystems, it is largely unknown how canopy water partitioning varies between co-occurring species, which has broad implications for water availability and forest flammability. Specifically these forests are undergoing a compositional shift from shade-intolerant, fire-tolerant oaks to shade-tolerant, fire-intolerant species (i.e., mesophytes) likely due to anthropogenic fire exclusion. To assess interspecific differences, we measured canopy and bark characteristics on 128 individuals of five different species of overstory and midstory trees (white oak, red oak, mockernut hickory, red maple, and winged elm). We compared these species with rates of stemflow, throughfall, and interception partitioning at monthly time scales.<br /><br /> Preliminary results show that overstory upland oaks partitioned 5.1% of rainfall into stemflow while mesophytic overstory species partitioned 7.2% into stemflow. In the midstory, mesophytes partitioned 1.5% to stemflow, while oak species only partitioned 0.9% to stemflow. These differences are likely manifested in soil moisture surrounding these trees. Results of this study will inform how trees move and store water and provide insights into the effectiveness of prescribed burning to restore and manage upland oak ecosystems.
Long-Term Effect of Cover Crop on Water Use Efficiency in Manured and Rainfed Soybean-Corn Rotations
Year: Authors: Yang W., Feng G., Adeli A., Jenkins J.
Planting winter wheat cover crops in corn and soybean rotations is an effective to improve the effective utilization of soil moisture and enhance water use efficiency. However, the longer-term impact of this practice needs to be further investigated. The hybrid RZWQM-DSSAT model calibrated with 5 yr (2013-2017) field data was used to simulate the effects of this practice on crop evapotranspiration, yield, and water use efficiency under a rainfed condition in no-till corn-soybean cropping system at Mississippi Agricultural and Forestry Experiment Station in Pontotoc Mississippi. The poultry litter (13.4 Mg ha<sup>-1</sup>) was applied to corn field with cover crop (CC) and no cover crop (NCC) in May 2014 and 2016. The model was calibrated well in terms of crop yield and biomass, plant N uptake, and soil moisture with percent error (PE) was within ±15%, Nash-Sutcliffe model efficiency (EF) > 0.7, and relative root mean square error (RRSME) < 15%. Longer-term simulations showed that planting a winter wheat cover crop increased corn yield by on average 1,560 kg ha<sup>-1</sup> (12%) and did not change soybean yield. The simulation also indicated that the practice increased annual evapotranspiration by 3.5 cm (9%) in corn years but did not affect evapotranspiration in soybean years. Simulated grain water use efficiency was increased by 17% for corn, and it was not changed in soybean. This study demonstrated that introducing winter wheat cover crops in a corn-soybean cropping system is a promising approach to increase corn water use efficiency in the subtropical agro-ecosystem.
NCCHE Modeling System for Water Resource Problems
Year: Authors: Zhang Y., Jia Y., Chao X.
This presentation gives a brief introduction of CCHE2D/3D model system and its capabilities. CCHE2D/3D is a state-of-the-art numerical modeling system developed at the National Center for Computational Hydro-science and Engineering (NCCHE) at the University of Mississippi. The model targets simulating water resource and environment related problems. It is capable of simulating free surface river flows, flooding/dam-break flows, sediment transport, morphological changes, chemical pollutant transport, environmental water quality, hurricane and coastal storm surge and wave processes. The model has been applied to simulate the city flooding of New Orleans, LA, caused by Hurricane Katrina the 2008 flood in the Mississippi River; sediment transport and water quality in the Lake Pontchartrain; pollutant transport and water quality in the Dan River, NC, caused by coal ash spill; flooding due to the storm surge of Hurricane Isaac 2012, Gustav 2008, Sandy 2012, etc. Since its initial development in the 1990s, it has been continuously developed and updated at the NCCHE and used by thousands of users in the US and worldwide. Many federal and state agencies have been CCHE2D users including USACE, USDA-ARS, NOAA, USGS, US Fish &Wildlife Service, USEPA, CA Dept. Water Res., Oak Ridge National Lab, North Alamo National Lab, US Navy Naval Oceanographic Office, US Marine Corps, Desert Res. Ins., National Disaster Preparedness Training Center, etc.
A Confluence of Water and Interdisciplinary Education: The Mississippi Water Security Institute
Year: Authors: Ochs C.
Social-ecological systems (SES) are comprised of humans, human cultures and perspectives, human institutions, and multitudes of diverse non-human residents. Clean water is the solvent of social-ecological systems, a resource upon which the components of these complex systems are linked and dependent for their economic prosperity, heath, and sustainability. To meet and protect the resource requirements of SES, governance and management approaches are necessary that account for and promote the interests and needs of diverse stakeholders. The Mississippi Water Security Institute is an undergraduate program designed to provide interdisciplinary education in the methods and challenges of water use and management in Mississippi, and the opportunities for new approaches to best meet present and future needs in support of the state's economic development. Emphasizing the complex, interdisciplinary nature of the topic, students in MS WSI represent a university of majors, from business and the social science to the natural sciences, and are recruited from Honors College programs across the state. In its first year (2016), MS WSI focused on water use and management in the rural Mississippi Delta, and last year we examined these issues with respect to the well-being of urban communities such as Jackson. This coming year, we turn our attention to water resource issues affecting well-being, prosperity, and resilience along coastal Mississippi. The MS WSI program involves in-class presentations by expert guests, discussion, and extensive time in the field. In both years of the program, students composed a White Paper detailing their individual and group learning experiences. Student assessment indicates strong satisfaction with the MS WSI interdisciplinary approach, experiential design, and the practical application of the subject matter, with several students stating that the program had reinforced interests in some aspect of water security as a career.
Understanding Relations Between Streamflow, Turbidity, and Suspended-Sediment Concentration in an Impaired Mississippian Stream
Year: Authors: Grafe J.N., Ramirez-Avila J.J., Schauwecker T., Ortega-Achury S.L., Czarnecki J., Langendoen E.
Sediment is listed as the most common pollutant in rivers, streams, lakes and reservoirs in Mississippi and the USA. Understanding the relations between suspended sediment concentration and measurements of turbidity and their temporal and spatial variability can be used as tools for assessing the effectiveness of programs for reduction of nonpoint source pollution. The Red Bud-Catalpa Creek watershed in Mississippi is currently listed by the Mississippi Department of Environmental Quality (MDEQ) as impaired by sedimentation and a Total Maximum Daily Load (TMDL) has been developed that sets challenging targets for sediment load reductions. Water quality parameters including flow velocity and depth, turbidity, suspended sediment concentration (SSC), specific conductivity, salinity, temperature and pH have been weekly monitored in 40 stations along the main stream and three headwater tributaries of the Catalpa Creek in Mississippi. The study is part of a research oriented to determine spatial and temporal variations of SSC and suspended sediment loads and to determine the relations among streamflow, SSC and turbidity in the evaluated streams. Positive correlations were initially observed between turbidity and SSC for most of the monitoring sites, but initial results have evidenced that a single relation may not be used to determine SSC for the entire watershed. Results have also evidenced key locations along the stream where erosion is a main concern, and highlights areas where erosion control actions are imperative and for which further research should be conducted.
The Use of Normalized Duration to Evaluate Low Flow in Mississippi Streams
Year: Authors: Johnson D.R.
Currently the Mississippi Department of Environmental Quality uses the lowest observed flow in seven consecutive days occurring in ten year period (7Q10) to establish minimum flows for streams. The 7Q10 is a minimum flow established for wastewater discharges, but it does not address the needs of aquatic organisms. The period of record flows from 128 streams in Mississippi were analyzed for annual duration. An index was developed based on the mean annual duration distribution. The index was compared to several methods that are commonly used to establish minimum environmental flows.
Developing Nutrient Criteria for Delta Waters: Expectations and Challenges
Year: Authors: Caviness K.
The Clean Water Act (CWA) requires each State to establish and maintain water quality standards (WQS) to meet the two objectives expressed in Section 101(a), which are as follows: (1) restore and maintain the chemical, physical, and biological integrity of the Nation's waters and (2) wherever attainable, achieve a level of water quality that provides for the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water. Consequently, WQS serve as the foundation for a wide range of water quality management programs under the CWA. WQS serve multiple purposes that include defining the water quality goals for a specific waterbody and providing the regulatory basis for establishing water quality-based effluent limits (WQBELs) beyond the technology-based levels of treatment required by CWA Sections 301(b) and 306. WQS also serve as a target for CWA restoration activities such as total maximum daily loads (TMDLs).<br /><br /> The CWA also states that WQS must include the following three elements including (1) designated use(s) for each water body, (2) water quality criteria necessary to protect these designated uses, and (3) antidegradation requirements. Since WQS establish the environmental baselines used for measuring the success of CWA programs, protection of the designated uses (aquatic life, recreation, sources of drinking water, etc.) depends on States developing and adopting well-crafted WQS.<br /><br /> In Mississippi, like many other states, excessive amounts of nitrogen and phosphorus are a major cause of surface water impairments. Since 2001, the Mississippi Department of Environmental Quality (MDEQ) has been working diligently to develop appropriate and protective numeric nutrient criteria (NNC) for Mississippi's waters. Nitrogen and phosphorus are natural parts of aquatic ecosystems and they are essential to supporting the growth of algae and aquatic plants, which provide food and habitat for fish, shellfish, and smaller organisms that live in aquatic ecosystems. However, when too much nitrogen and phosphorus enter the environment, streams, rivers, lakes, estuaries, and coastal waters may be impacted.<br /><br /> Developing NNC is extremely complex at every step of the process from selecting the appropriate endpoint that demonstrates support of the designated use to ultimately determining the concentration of nitrogen and phosphorus that will achieve that desired endpoint. Additional complexity is added by the numerous other confounding factors that occur within aquatic environments and their biological communities that are also affected by habitat, sunlight, flow, and numerous other variables that are different for every water body. Establishing NNC becomes even more complicated in the MS Delta region of the State due to the extent of historical stream and channel alteration as well as other physical and chemical characteristics that are unique to this region of the state.<br /><br /> Designated uses are a critical component of WQS because the use of the water body is used to define the appropriate water quality goals to protect that use. Mississippi currently has a very simple water body classification structure. One aspect of the current classification structure that has been criticized is how the State classifies waters within the MS Delta. Even though there are numerous water body types present in the MS Delta, from large rivers to bayous, every water body currently has the same designated use and thus the same expectations. MDEQ is examining the current water body classification structure and investigating further refinement of this structure. Further refinement of water use classifications will allow MDEQ to provide a more accurate distinction between water bodies around the state and allow for more appropriate criteria (or goals), including the development of nutrient criteria, to be established for those various water bodies.
Water Quality Improvements from Implementation of Tailwater Recovery Systems
Year: Authors: Omer A.R., Baker B.H.
Impacts of nutrient loading from agricultural landscapes have gained widespread attention and led to the implementation of conservation practices aimed at mitigating nutrient loss to downstream systems. Tailwater recovery (TWR) systems, have been considered as a potential mitigation strategy. The objective of this study was to compare concentrations and loads between effluent of TWR systems (TE) and effluent of similar catchments without TWR systems (CE), under the same agronomic management. Tailwater recovery systems, CE, and paired differences between TE and CE were compared over seasons. Nutrient concentrations and hydrologic discharge were monitored at five TWR system outflow and control catchment outflow locations on a flow event basis. Results revealed that of all experimental analytes, including total suspended solids, total phosphorus, total Kjeldahl nitrogen, nitrate-nitrite, and ammonium, only total phosphorus concentrations were greater (<em>F</em><sub>1,97</sub> = 8.58, p < 0.005) at CE locations than TE locations. The difference between loads of TE and CE showed reduced loads per hectare leaving TWR systems. This included loads of total phosphorus, total nitrogen, organic nitrogen, total inorganic nitrogen, and nitrate-nitrite. Analyses revealed no differences across seasons for TE and paired differences between TE and CE. However, CE concentrations and loads were seasonally different, where ammonium was greater in the summer than in the winter and spring but not different than fall. Additionally, only loads of total nitrogen were different across seasons, where winter was greater than spring but not different than summer and fall. This study provides evidence that TWR systems are a positive contribution to reducing nutrient loads compared to control locations.
The Effects of Cover Crops on Runoff, Erosion, and Off-Site N and P Transport
Year: Authors: Spencer D., Krutz J., Locke M., Henry B., Golden B.
There has been increasing interest in incorporating cover crops into production systems in the Midsouthern United States. Studies were established in Stoneville, MS to determine the effects of four cover crops on water use efficiency, runoff, erosion, and off-site N and P transport in a continuous corn production system. Treatments consisted of a reduced till/no cover (RTNC) as a control, reduced tillage with cereal rye (CR) (<em>Secale cereal</em> L.), reduced tillage with Austrian winter pea (AP) (<em>Pisum sativum</em> L.), reduced tillage with tillage radish (TR) (<em>Raphanus sativus</em> L.), reduced tillage with crimson clover (CC) (<em>Trifolium incarnatum</em> L.), and no till/no cover (NTNC). A portable rainfall simulator was used to simulate precipitation and the resulting runoff was captured from each plot to determine flow, sediment load, and N and P transport. Austrian pea increased infiltration by 24.7% relative to the RTNC plots. CR resulted in higher amounts of PO<sub>4</sub> and total Kjeldahl nitrogen (TKN) in the runoff water than the control and higher amounts of NH<sub>4</sub> than all other treatments except the RTNC. Also, furrows which received equipment tire traffic had lower amounts of NH<sub>4</sub> and TKN than furrows not receiving tire traffic. Lastly, corn grain yield was 40 and 45% lower in the AP and CR plots, respectively, than the RTNC control. These results indicate that there is potential for some cover crops to improve infiltration in the Mid-south, however, more research is required to understand the effects on corn grain yield and nutrient transport.
Predicting the Effects of Conservation Practices in Tropical Soils
Year: Authors: Wilson L.E., Ramirez-Avila J.J., Almansa-Manrique E.F.
Understanding the implications of conservation management practices on runoff and erosion from agricultural fields is important to determine subsequent impacts on soil health, crops productivity, and the overall environment in a watershed. By establishing better practices to improve soil health, the crops will also be more productive, while keeping the impact on the environment to a minimum. In the Eastern Savannahs of Colombia, agricultural production became a very important part of the national economy. However, soils in the region are prone to high erosion and loss of soil fertility if adequate conservation management practices are not established. Fields in the area growing soybean, corn, and rice on rotation under conventional tillage, reduced tillage, and direct planting were studied at the Experimental Station La Libertad (CORPOICA) in Villavicencio, Colombia. The ability of APEX (Agricultural Policy/Environmental eXtender) to predict runoff, sedimentation, and nutrients present in the eroded material is evaluated using observed climate, runoff, sediment, nutrients, and crop yield data. Using the calibrated models, a better understanding of short and long term effects of implemented management practices is achieved, and the best management practice with regards to the economy and environment health can be identified.
Streamflow Alteration Assessments to Support Bay and Estuary Restoration in Gulf States—Overview
Year: Authors: Knight R.R.
Human alteration of waterways has affected the minimum and maximum streamflow in more than 86 percent of monitored streams nationally and may be the primary cause for ecological impairment in river and stream ecosystems. Restoration of freshwater inflows can positively affect shellfish, fisheries, habitat, and water quality in streams, rivers, and estuaries. Increasingly, state and local decision-makers and Federal agencies are turning attention to the restoration of freshwater flow as part of a holistic approach to restoring water quality and habitat in rivers and streams and to protecting and replenishing living coastal and marine resources and the livelihoods that depend on them.<br /><br /> In 2017, the U.S. Geological Survey, in collaboration with the U.S. Environmental Protection Agency, began a comprehensive, large-scale, state-of-the-science project to provide vital information on the timing and delivery of freshwater to streams, bays, estuaries, and wetlands of the Gulf Coast. Ecologically relevant streamflow metrics and measures of streamflow alteration will be developed for streams throughout the five Gulf States and made available via an online mapping tool. An assessment of trends in streamflow delivery to Gulf Coast estuaries will improve the understanding of potential drivers of change in estuarine health. A streamflow accounting model will be developed for one large watershed in the five Gulf States to evaluate and understand how streamflow alteration at locations in the upper basins may influence the magnitude, timing, duration, and frequency of freshwater flows to the Gulf. This model will provide local, state, and Federal officials the ability to evaluate how streamflow withdrawals and reservoir operations throughout the watershed may have altered streamflow metrics and affected freshwater inputs to the estuary.<br /><br /> Key questions this study will help address include:<br /><br /> Gulf-Wide Assessment <ul><li style="list-style: circle; list-style-position: inside;">Which streams in the Gulf States have the largest amounts of streamflow alteration?</li> <li style="list-style: circle; list-style-position: inside;">What are the gaps in streamflow data for assessing streamflow alteration in Gulf States?</li> <li style="list-style: circle; list-style-position: inside;">Are shifts in magnitude, timing, duration, and frequency of freshwater delivery to estuaries due to altered streamflow distinguishable from natural signals?</li></ul><br /><br /> Large Watershed Assessment <ul><li style="list-style: circle; list-style-position: inside;">How far downstream from alteration points do substantial shifts in streamflow metrics occur? </li> <li style="list-style: circle; list-style-position: inside;">How sensitive are estuary freshwater inputs to upstream streamflow alterations? </li> <li style="list-style: circle; list-style-position: inside;">Is there a threshold of freshwater alteration below which no signal is detected in an estuary?</li></ul>
Predicting Daily Streamflow Using L-Moments and Neural Networks
Year: Authors: Worland S., Knight R., Asquith W.
Various statistical methods have been evaluated and applied to estimate daily mean streamflow and other streamflow statistics for ungaged streams and regional characterization. We elected to estimate daily streamflow in ungaged basins using flow duration curves (FDCs), L-moments, and machine-learning. The method is an extension of the Q<sub>1</sub>P<sub>1</sub>P<sub>2</sub>Q<sub>2</sub> method that uses streamflow at gaged locations (Q<sub>1</sub>, streamflow at the gaged site) to calculate a time series of exceedance probabilities (P<sub>1</sub>, exceedance probabilities at gaged site) that are used streamflow at the ungaged site) at ungaged locations. The workflow requires estimating a FDC for an ungaged basin—a step achieved using L-moments to summarize the distributional geometry of FDCs and statistical regionalization models. We regionalize the first four L-moments computed from 10-year blocks of daily streamflow data from 1950–2010 for 1,030 gaged-basins that span from southern Texas to Florida. The decadal approach results in 3,027 L-moment ensembles available for regionalization. Out-of-sample predictions are used to simulate method performance at ungaged locations. The specific steps are (1) calculate decadal L-moments at gaged locations, (2) use multi-output neural networks and 34 basin descriptors to regionalize L-moments to ungaged catchments, (3) parameterize an analytical flow duration curve at the ungaged locations using the regionalized L-moments, (4) select donor sites using distance matrices in basin-descriptor space, and finally, (5) use the donated probabilities (P<sub>1</sub>P<sub>2</sub>) to generate daily streamflow values at ungaged locations. Additionally, compensation for no-flow conditions is made through logistic-regression like modeling. Uncertainty is incorporated into the predictions using stochastic neural-network dropout to approximate a posterior distribution of L-moments and streamflow estimates.
Estimating Streamflow-Recession Indices Using Automated Methods with Application to Groundwater-Surface Water Interaction
Year: Authors: Crowley-Ornelas E., Knight R.R., Asquith W.H.
Statistical properties of streamflow recession provide evidence of hydrologic processes such as groundwater and surface-water interactions. Bingham (1982, 1986) sought regional definition of generalized connectivity between surface water and groundwater by calculating a persistent streamflow recession slope during winter low flows and then relating the recession slopes to surficial geology. For our study, the recession slope value was referred to as the Bingham "geologic factor" or G factor. <br /><br /> The recession slope determined by Bingham's process was somewhat subjective because it was hand drawn based on the visual inspection of the stream hydrograph. The G factor was derived through a hands-on graphical method for selected peak flows over a 20-year time period from U.S. Geological Survey (USGS) streamgages in Tennessee and Alabama. A streamflow recession curve, plotted on semi-log graph paper, was created by starting at peak streamflow after a precipitation event until the line neared asymptotic with the x-axis. The number of days (x-axis) required for streamflow to decrease one log cycle (y-axis) was the index of streamflow recession for each station, or the G factor expressed in days per log cycle decline in flow. Boundaries for G factor regionalization were determined using streamflow hydrographs, surficial geology, and lithologic contacts. Although G factor values have been useful in statistical regionalization studies (Bingham, 1982, 1986; Knight and others, 2012), the subjectivity and time-consuming manual method of the approach has made it problematic to calculate G factors for newer records and different regions. <br /><br /> The USGS has developed an automated process that calculates G factors and has applied this method to more than 300 streamgages and more than 4 million days of streamflow at streams in or bordering Tennessee. Results from the automated process will be compared to the original G factor estimates to assess whether this new method is capturing the same hydrologic process information. Using the one-way layout statistical method, the relative impact of factors such as soil type, aquifer outcrop, and lithology on G factors will be assessed to create a regionalization of G factors across Tennessee.<br /><br /> Developing an automated process using existing data to calculate the G factor will make it possible to estimate the factor for larger areas as well as for discrete time periods. This new approach, if successful, will provide a tool to evaluate the extent of connectivity between surface water and groundwater in a basin; the influence of groundwater withdrawals on baseflow; and could be an early indicator of potential drought effects.
Nutrient and Pesticide Mitigation by Common Aquatic Plants
Year: Authors: Moore M.T., Locke M.A.
While some debate the severity, all agree that agriculture contributes to non-point source pollution issues. The challenge of feeding and providing fiber for a rapidly growing national and global population results in more marginal land being utilized for production acreage. As a result, conservation planners must look for innovative, cost-efficient practices to minimize impacts of agricultural runoff containing pesticides and nutrients. To that end, twelve experimental mesocosms (1.3 x 0.7 x 0.6 m) were established with a 16 cm of Lexington silt loam atop a base of sand (22 cm). Mesocosms were planted in monocultures of either <em>Myriophyllum aquaticum</em> (parrot feather), <em>Polygonum amphibium</em> (water knotweed), or <em>Typha latifolia</em> (common cattail). Three mesocosms were also left unvegetated to serve as controls. All mesocosms were amended with target concentrations of 10 mg L<sup>-1</sup> (each) nitrate, ammonium, and orthophosphate; 20 µg L<sup>-1</sup> (each) of the pesticides propanil and clomazone; and 10 µg L<sup>-1</sup> of the pesticide cyfluthrin. After a 6 h amendment of simulated agricultural runoff, mesocosms sat idle for 48 h before flushing with unamended municipal water for another 6 h. Outflow water samples were routinely collected and analyzed for contaminant concentrations. No significant differences were noted between the control and any of the three different vegetation types regarding the percent contaminant retained within the hydraulic time retention time. Most significant differences between vegetated mesocosms and controls occurred when comparing mean contaminant breakdown rates post-amendment. <em>Typha</em> indicated significantly greater PO<sub>4</sub>, NH<sub>4</sub><sup>+</sup>, TOC, TKN, TP, clomazone, propanil, and cyfluthrin breakdown percentages than controls during post-amendment (8–48 h). Likewise, <em>Myriophyllum</em> demonstrated significantly greater breakdown post-amendment for PO<sub>4</sub>, TOC, TKN, TP, clomazone, and propanil when compared to controls. <em>Polygonum</em> had greater NH<sub>4</sub><sup>+</sup>, NO<sub>3</sub><sup>-</sup>, TOC, TKN, TP, clomazone, propanil, and cyfluthrin breakdown percentages than controls during post-amendment. All three plant species had significantly greater percent propanil and cyfluthrin retention after the 6 h "clean" flush when compared to controls. These variable results indicate the importance of not only examining a variety of aquatic plants and their contaminant mitigation efficiency, but also determining potential downstream wash-off effects from multiple runoff events. Using natural systems, such as ditch vegetation, in the mitigation of agricultural runoff is a critical research area which must be further explored.
Factors Controlling Salinity in Nearshore Waters of the Mississippi Sound, MS
Year: Authors: Swarzenski C.M., Mize S.V.
Magnitude and variability of salinity of shallow waters shape estuarine living resources and habitat. The salinity gradient is widely recognized as foundational in maintaining biological diversity and productivity of estuaries. Thus, a clear understanding of the factors controlling salinity and variability of salinity in estuarine surface waters is essential for proper stewardship and for sustaining ecological structure and function. Salinity of estuaries is controlled by freshwater inflows, estuarine circulation and climate (storms, episodic droughts and trends in precipitation). To better understand the factors governing salinity and its variability in the Mississippi Sound, the U.S. Geological Survey is compiling all available current and historic salinity data. This effort will assist scientists in understanding the effects of current and future restoration projects on salinity and salinity variability in the Mississippi Sound. Such projects include the current efforts to rejoin Ship Island, which will affect water circulation patterns, and the implementation of massive river diversions into the Breton Sound basin in Louisiana, which will add considerable amounts of freshwater to the nearshore waters of the Mississippi Sound.
Field Measurements of Irrigation Reservoir Levee Erosion
Year: Authors: Wren D.G., Ozeren Y., Reba M., Bowie C.
The use of surface water resources for irrigation has increased due to groundwater depletion. In order to reduce dependence on groundwater, irrigation reservoirs and tailwater recovery systems can be used to capture and store water for irrigation. Irrigation reservoir levees are typically constructed from local soils with low cohesion, resulting in levees that are susceptible to erosion by wind-driven waves, necessitating frequent repairs that are an added expense for producers. Motivated by the amount of erosion observed on the levees, a survey was conducted in 2013-2015 to assess the current condition of the levees and attempt to identify common factors for highly eroded sections. It was found that 79% of the 584 homogeneous levee segments contained within 148 surveyed reservoirs had block failures and near-vertical slopes. Despite regional winds with preferential southerly and northerly directions, levees of all orientations were damaged by waves. For the surveyed irrigation reservoir levees, soil type, vegetation, inner slope, and berm presence were found to be poor predictors of the state of impairment. The most important variable associated with levee failure was maximum effective fetch length; levee segments with longer fetches were more likely to have block failures and greater losses of top-width.
Assessment of Slope and Mechanical Treatments for an Irrigation Reservoir Embankment
Year: Authors: Ozeren Y., Wren D.G.
On-farm irrigation reservoirs are commonly used in the Mississippi River Valley alluvial floodplain to complement limited groundwater resources. The inner slopes of the earthen embankments of these reservoirs are subjected to continuous erosion due to wind-generated waves. Various methods were applied in the past to protect the levees but none of these methods were sustainable and cost effective. In order to compare their effectiveness against wave erosion, several treatment techniques were applied on the levees of an irrigation storage reservoir at the University of Arkansas Pine Bluff (UAPB) Lonoke Demonstration Reservoir in 2007. The treatment techniques included 17 different slope configurations along the east and west embankments, as well as 5 different mechanical treatments along the north and south embankments. In 2015 and 2017, USDA-ARS and The University of Mississippi carried out two comprehensive surveys along the embankments of the UAPB reservoir. The surveyed cross-sections were compared with the as-built cross-sections to quantify the loss of soil so that the effectiveness of the treatment methods could be evaluated. Almost all of the slope configurations significantly eroded over the past 10-years. In general, milder slopes performed better than the steeper slopes. Although having a berm did not reduce the total eroded volume significantly, in most cases it delayed the bank top retreat. For sections with identical slope configurations, the section with the longest maximum fetch, regardless of bearing, typically had the highest erosion and bank top retreat. The survey results showed that mechanical treatment methods were more resilient against wave action as compared to the slope treatment methods.
Measurements of Physical Characteristics of Earthen Levees for Small Lakes in Mississippi
Year: Authors: Andrews W., Ozeren Y., Wren D.G.
The state of Mississippi has many aging earthen levees, but the current status of the levee system is unknown. Many of the levees in Mississippi have exceeded their 50-year design life, and the possibility of a critical failure on one of the levees is increasing with time. The overall goal of this project is to create a computer model to simulate a critical failure of a levee and analyze how it would affect the surrounding area and the surrounding population. However, a computer model cannot be created without knowing the mechanical properties of each levee. Through a grant from MDEQ, the National Center of Computational Hydrological Engineering (NCCHE) was tasked with finding these mechanical properties by performing in-situ tests and to collect soil samples from fifteen levees throughout the state of Mississippi. The soil samples were taken at three different locations near the middle of each levee. At each location, one 6-in diameter sample was collected for jet erosion testing, and two 2-in diameter samples were collected for bulk density measurements and soil texture analysis. It was found that the range of the critical shear stress varied from 10 Pa to 130 Pa. The older dams had a higher critical stress due to longer amount of time for the soil to consolidate. The 2-in samples showed the soil texture of each levee. For example, the levee at Lake Druid in Meridian, MS, was composed of 30% clay, 41% silt, and 29% sand. With this information on the mechanical properties of each levee, more accurate simulations of levee breaches can be made, leading to better understanding of the aging levee system in the state of Mississippi.
Remotely Sensed Channel Emergence with Both Till and No-Till Management Systems
Year: Authors: Wells R.R., Momm H.G., Vieira D., Bingner R.L.
Ephemeral channels appear in agricultural fields under a host of conditions. The spatial emergence is primarily driven by topography, tending to increase or decrease the erosive forces of runoff, whereas the temporal component, represented by geomorphologic response over time, is much less understood. In this study, agricultural fields in Iowa were selected based upon potential for channel formation and management practices. Aerial topographic surveys were collected following planting in till and no-till managements, where localized climate measurements were obtained, then another aerial topographic survey was collected a month later. A novel surveying approach was designed by combining unmanned aerial vehicles (UAVs) with digital photogrammetry, differential global coordinate system (DGPS), and integration of on- and off-field ground control points. Each survey was anchored to a global coordinate system (GPS) via targets surveyed using GPS equipment and established static field monuments, ensuring that coordinate system solutions from the two aerial surveys of the same site were horizontally and vertically aligned. Custom algorithms were employed to process generated point clouds and produce geospatial datasets at centimeter spatial resolution. Difference mapping of the temporal topographic surveys combined with the climate measurements from each location provides guidance for temporal erosion components (i.e. the erodibility parameters) within erosion models such as RUSLE2. Conservation planning can be improved through time series of high resolution topography surveys that provides enhanced information on where problems are within agricultural fields and data to erosion management technology needed to evaluate conservation practices targeted to the existing problems.
Hypoxia in the Mississippi Bight: Understanding Interactions of Circulation and Biogeochemistry in a Complex River-Dominated Coastal Ecosystem
Year: Authors: Shiller A.M., Sanial V., Moore W.
Coastal areas are key regions between the continent and the open ocean where land-derived chemical elements transported by rivers and groundwater mix with seawater. Coastal areas are very productive regions that are particularly vulnerable to human activities. The coastal waters to the east of the Mississippi River Delta, including the Mississippi Sound and Bight, are relatively understudied compared with the Louisiana Shelf to the west. Nonetheless, the Mississippi Sound and Bight contain productive fisheries, are subject to environmental issues such as oil spills, and experience seasonal hypoxia. The CONCORDE Consortium and other projects have recently been investigating this complex, river-dominated ecosystem. Because the Mississippi Sound and Bight receive fluvial inputs from various states and is comprised of both state and federal waters, potential management efforts are also complicated. In this presentation, we explore the interactions of different source waters with an emphasis on bottom water hypoxia in this system. With oxygen isotopes, we find that outflow from the Mississippi River is typically not the dominant freshwater source to the Mississippi Sound/Bight region. Furthermore, with naturally occurring radium isotopes, we observe a significant influence of submarine groundwater discharge (SGD) in bottom waters that is also correlated with hypoxic conditions. This relationship suggests that "bottom-up" influence of reduced substances on oxygen consumption can be an important contributor to hypoxia.
The Louisiana, Mississippi, Alabama Coastal System (Lmacs); Embracing Functional Boundaries to Drive Comprehensive Estuarine Restoration
Year: Authors: Ramseur Jr. G.S., Ferraro C., Pahl J.W.
The LMACS is a restoration planning area that is based upon functional boundaries of the coastal estuary that spans from Lake Borgne to Mobile Bay and extends seaward to the Biloxi Marsh in LA and the barrier islands in MS and AL. The idea of using this area as a basis for multi-state restoration coordination recently grew out of long standing partnerships between the principal agencies (listed above) that developed in the Gulf of Mexico Alliance (GOMA). Many other agencies, nongovernmental organizations and institutions of higher learning are already engaged in work that may be synergistic with this concept. For example, efforts are ongoing to improve cross-border sharing of hypoxia and other water quality data. The networks and protocols that develop through these interactions will make it much easier to identify additional data needed to support a comprehensive assessment of the LMACS.<br /><br /> The primary goal of this partnership is to conduct comprehensive hydro- geophysical, biochemical and economic modeling of the LMACS which will be used to develop a restoration "master plan" for the estuary. This plan, the Restoration Framework for Sustainable Fisheries (RFSF), will assess geomorphic and other restoration approaches to support the long-term recovery and stability of traditional oyster, shrimp and fin fisheries. Aspects of the built environment and the human communities that depend directly on these resources will also be addressed. The intention is for the RFSF to guide restoration project development, prioritization, and implementation over a 50-year horizon to improve synergies with ongoing efforts such as the Louisiana Coastal Master Plan.<br /><br /> The geomorphic history and anticipated trajectory of the LMACS estuarine barrier is of significant interest for our team. Ongoing erosion and fragmentation of the Biloxi Marsh and barrier islands are causing the system to become increasingly marine. This geomorphic instability will likely drive a unique set of restoration priorities compared to similar class estuaries such as the Chesapeake Bay.
The Development of a Hydrodynamic/Water Quality Model for Oyster Restoration in the Western Mississippi Sound
Year: Authors: Armandei M., Linhoss A.
This study presents the development of a hydrodynamic and water quality model for the western Mississippi sound. The model was developed using the Visual EFDC program, which is an "advanced, 3D, time variable model" that links hydrodynamics with sediment transport and water quality modules. A computational grid has been generated consisting of 4 layers, each having 3000 cells. The cell size range is 1000m <u><</u> DiameterCell <u><</u> 3000m. The input data for the hydrodynamic model are water level, water temperature, salinity, and other meteorological data such as precipitation, and were mostly collected from the measurement stations of NOAA (National Oceanic and Atmospheric Administration) and USGS (United States Geological Survey). The hydrodynamic model was calibrated for the time period of Jan 1 to Dec 31, 2016. A sensitivity analysis is being performed in the light of which the parameters that most impact oysters in the western Mississippi sound will be identified. The model will be useful in identifying appropriate locations for oyster restoration in the western Mississippi Sound.
Examining the Effects of Directional Wave Spectra on a Nearshore Wave Model
Year: Authors: Dillon C., Linhoss A., Jensen R., Smith J., Skarke A.
Wave models are an integral part of coastal engineering due to their ability to quantitate information that is either unobtainable or unavailable. However, these models rely heavily on their inputs for accuracy. One critical input for nearshore models is the directional wave spectrum. The directional wave spectrum is the product of a frequency spectrum and a directional spreading function. There are many ways to compute the directional wave spectra depending on how either the frequency spectra or the spreading function is computed. <br /><br /> In this study, five methods for computing the directional wave spectrum were investigated. Using an offshore buoy, a Fast Fourier Transformation (FFT) of the time series of the buoy's heave generated a frequency spectra. Directional coefficients generated by the FFT were used to calculate three directional spreading functions: the maximum entropy method, the maximum likelihood method, and the Longuet-Higgins method. Using only the observed mean wave direction, the significant wave height, and the peak period from the offshore buoy, a frequency spectra was generated using the JONSWAP method, which applies a parametric shape based on the observed parameters. Since no FFT coefficients were created a cosine squared and a cosine 2s spreading function were used with the JONSWAP frequency spectra. <br /><br /> This study investigated how these five directional wave spectra perform within the nearshore spectral wave model, STWAVE. To accomplish this task, STWAVE was run five times in a half plane mode, meaning only wave propagation towards shore is retained. Each experimental run contained a different directional wave spectral computation, a bathymetry grid of 100 by 100 m resolution, a constant JONSWAP bottom friction value of 0.004, and spatially constant winds taken from the offshore buoy. No currents or changes in water level were included. <br /><br /> The results of the five experimental runs show that direction was the most affected parameter by the directional wave spectra input. Many differences observed between the five directional wave spectra occurred due to the differing placement of energy in the higher frequencies between the two frequency spectra methods, thus affecting where wave-bottom interaction begins. Another conclusion of this study, is that for the study's environment, which was shallow and low energy, the wave-bottom interactions dictate the spectra in the nearshore. Thus, no matter the complexity of the directional wave spectra used as the model input, the wave-bottom interactions will tend to converge all spectra according to the limits of the bathymetry.
Hydrologic and Nutrient Removal Performance of Rain Gardens: A Review
Year: Authors: Ly P., Ramirez-Avila J.J.
As the intensity of hydrologic events and concerns of pollutants in stormwater runoff increase, it is critical to recognize the importance of stormwater management. Thus, best management practices (BMPs) have been developed as control measures against the potentially detrimental effects caused by excess runoff. Structural or institutional BMPs have been proven to successfully manage stormwater runoff, improve runoff quality, and mitigate effects of erosion. Rain gardens or bioretention facilities have been used as a structural BMP to filter pollutants from runoff and mitigate erosion by slowing runoff volume and velocity. However, because of the great variability in soil type, vegetation, rainfall conditions, and many other parameters, it is difficult to assess the hydrologic efficiency of a given rain garden. Past research has quantified rain garden's performance in terms of volume of the system's inflow, outflow, and removal of nutrients and heavy metals. Because a good understanding of design configurations, climate conditions, and temporal relationships are crucial for the efficient performance of a rain garden, a study aimed to compare and contrast results on previous rain garden research, in order to determine correlations between design configurations and their potential to both, flow and pollutant loads. From these compiled studies, it was found that hydraulic conductivity is a major design parameter to be considered as high infiltration leads to greater hydraulic performance, but poor nutrient removal. Inherent soil properties such as the soil test phosphorus are also indicative of how well the rain garden will perform in terms of water quality.
Can Controlled Experiments Play a Role in Informing Nutrient Management Goals for Mississippi Alluvial Plain Water Bodies?
Year: Authors: Taylor J., Lizotte R.
Field-derived stressor-response models are useful for establishing nutrient management goals that protect ecological integrity of regional water resources. However, these studies can be difficult to implement in large river floodplain regions with intensive agricultural for a variety of reasons including: general habitat limitation of lowland stream ecosystems; significant alteration of geomorphological and hydrologic regimes; and a lack of clearly defined nutrient gradients among sites due to widespread enrichment. Given the diverse potential confounding factors and challenges to deriving nutrient stressor, ecological response models within the Mississippi Delta, conducting field mesocosm experiments may provide additional empirical evidence to evaluate field observations and inform nutrient reduction goals. We will explore this option by first, briefly presenting examples from a nutrient stressor-response study conducted in Texas that demonstrates how controlled stream mesocosm studies can 1) confirm field-derived stressor-response relationships and 2) identify relationships difficult to see with field data due to confounding factors. Secondly, we will present results from field mesocosm studies that demonstrate heterotrophic and autotrophic responses to nutrient enrichment within Delta habitats. We will conclude by discussing how experimental mesocosm studies can be expanded and conducted to inform identification of nutrient management goals for water bodies within the region.
Can Diatom Assemblages Identify Important Stressor-Response Relationships Necessary to Establish Nutrient Management Goals for Mississippi Alluvial Pl
Year: Authors: Hicks M., Taylor J.
Anthropogenic alterations to large river floodplains like the Mississippi Delta disrupt natural disturbance regimes that typically maintain the ecological integrity of lowland stream ecosystems. Anthropogenic activities can also cause shifts in water quality, such as conversion of forested floodplains to intensive agriculture that leads to potential excess nitrogen and phosphorus in runoff to streams. As a result, streams within the Delta are generally habitat limited, exposed to alterations of natural temporal and acute geomorphological and hydrologic regimes, and often experience widespread nutrient enrichment. All of these factors limit development of field-derived stressor-response relationships to establish nutrient reduction goals as one mitigation effort to improve ecological integrity. To address this limitation, in 2015, the U.S. Geological Survey sampled diatom assemblages from 25 streams that were located within the Mississippi Alluvial Plain (MAP) ecoregion in Mississippi but drained portions of upstream ecoregions with greater variation in land management and represented a measurable gradient in total phosphorus (TP) and total nitrogen (TN). We collected epidendric diatom assemblage samples from instream woody debris as this was the primary stable habitat for diatom colonization found within our study systems. Ordination analysis identified a gradient in species composition associated with increasing TP and decreasing dissolved oxygen. Additional variation in assemblage structure was correlated with increasing alkalinity. Our results indicate that diatom assemblages are responsive to phosphorus enrichment and show promise for deriving stressor-response relationships and identifying nutrient reduction targets within Delta streams. However, additional work is needed to better quantify stressor-response relationships. Specifically, using standardized artificial substrates for diatom collection could improve precision, increasing the range of field gradients by adding more sites at low and high nutrient concentrations, and conducting controlled experiments to verify field-derived results will improve future efforts to establish defensible stressor-response relationships for nutrients within Delta streams.
Sources of Hypoxia in Mississippi Delta Streams
Year: Authors: Lizotte R.
Rivers and streams in watersheds with intensive row-crop agriculture are vulnerable to ecological impairment associated with non-point source runoff. Agricultural watersheds impacted by elevated nutrients can exhibit eutrophication, producing periods of severe oxygen stress or hypoxia (dissolved oxygen concentrations<u><</u>2 mg/L). Additional factors such as hydrology and channel morphology as well as sporadic influxes of dissolved organic matter (sometimes referred to as blackwater) can exacerbate oxygen stress. From 2011-2017, we monitored biweekly summer and fall nutrients (total nitrogen and total phosphorus), chlorophyll α, dissolved organic carbon, and daily dissolved oxygen (one-week deployments) within three low-gradient, low-flow stream bayous in the Mississippi Delta. Eutrophication-induced hypoxia exhibited diel dissolved oxygen patterns with hypoxia primarily occurring during late night to early morning hours throughout the summer months. Periods of eutrophication-induced hypoxia lasted an average of 29 h or 17% of a 168 h (one-week) deployment period. In contrast, blackwater-induced hypoxia occurred sporadically following intense rainfall events typically <u>></u>25.4 mm falling on dry row-crops prior to harvest (late summer to early fall) producing dissolved organic matter-laden runoff and dissolved oxygen sags. Periods of blackwater-induced hypoxia lasted an average of 84 h or 50% of a one-week deployment period. Classification and Regression Tree (CART) analysis of eutrophication-induced hypoxia produced a model indicating that stream morphology as channel width and elevated nutrients and total nitrogen worsened hypoxic conditions. CART analysis of blackwater-induced hypoxia produced a model indicating that elevated dissolved organic matter, decreased water depth and inhibition of photosynthesis worsened hypoxic conditions. Monitoring results indicate that reduction of both nutrients and sporadic dissolved organic matter pulsed inputs to low-flow Mississippi Delta streams is necessary to help mitigate hypoxic conditions and improve summer to fall dissolved oxygen concentrations in agricultural streams.
Despite their differences, managed and non-managed wetlands in the Mississippi Delta achieve similar functional outcomes
Year: Authors: Ervin G.N., Shoemaker C.M.
This project aimed to evaluate abiotic and biotic characteristics of restored and non-managed wetlands in the Mississippi Delta, in an effort to determine whether restored wetlands are achieving desirable ecological functions in this predominantly agricultural landscape. With the assistance of USDA-NRCS, we identified 24 Wetland Reserve Program (WRP) wetlands and 6 non-restored, non-managed wetlands (NMW) for this work. These wetlands were assessed during 2014 and 2015 for water quality, hydrology, plant species composition, and landscape setting, as metrics of ecological condition and function.<br /><br /> Hydroperiods differed between NMWs and WRP sites, with longer, more intense flooding observed in NMWs; these differences were correlated with lower levels of plant species diversity, richness, and evenness in the NMWs, compared to WRP sites. We also found significant differences in soil organic matter content between wetland types, with NMWs having higher soil organic matter content, also likely correlated with the differences in hydroperiod between groups. In contrast to our observations of plant species and soils in these wetlands, few differences were found in water quality parameters between the two groups of wetlands. <br /><br /> At a broader scale, we found that WRP sites tended to be surrounded by higher levels of agriculture and conservation land, at distances from 100 to 500 m from the wetland edge, while NMWs tended to be surrounded by greater amounts of forested wetland cover. Additionally, we found that the conservation status of plant species in NMWs tended to be higher than that for WRP wetlands, which typically are situated in former marginal agricultural lands. Nevertheless, the lack of any substantial differences in water quality between NMWs and WRPs suggests that removal of excess nutrients associated with agricultural practices can be accomplished by wetlands across the agricultural landscape, even in moderately to heavily disturbed systems, such as the moist-soil managed wetlands typically created under the WRP efforts.
Chemical control of the floating aquatic plants common duckweed (<em>Lemna minor</em> L.) and watermeal (<em>Wolffia</em> spp.)
Year: Authors: Turnage G.
Floating plants are increasingly becoming widespread problems in waterways in the southern United States. Nuisance problems are often exacerbated with increased nutrient inputs into waterbodies from point and non-point sources. Common duckweed (<em>Lemna minor</em> L.) and watermeal (<em>Wolffia</em> spp.) are both floating aquatic plant species that can be problematic in southeastern waterbodies. Infestations of these species can reduce the use and aesthetics of waterbodies and can shade out submersed aquatic plants potentially causing oxygen depletions in which may result in fish kills. Duckweed and watermeal are some of the most difficult aquatic species to control due to their high rate of reproduction. Most management options utilizing chemical control methods produce inconsistent results when used on these species. This work analyzed the effects of the contact herbicide diquat and a new liquid formulation of the contact herbicide flumioxazin when used to control duckweed and watermeal. Each species was established in 20 40L aquaria in a greenhouse and were allowed to grow for one month prior to herbicide applications. Diquat was applied to each species at the maximum label rate while flumioxazin was applied to each species at low, medium, and high rates. All herbicides and rates reduced duckweed by four weeks after treatment (WAT) when compared to an untreated control. Diquat and the high and medium rates of flumioxazin reduced watermeal when compared to the untreated control at four WAT, however the low rate of flumioxazin did not.
Estimates of Suspended-Sediment Yields for Select Streams in Mississippi
Year: Authors: Runner M.
Stream quality can be impaired by changes in the quantity and quality of suspended sediment and stream paths and flows can be altered by erosion and deposition. Thus, it is important to monitor suspended-sediment loads and yields of stream basins to establish reference or background sediment- transport characteristics for streams in a given region or basin, as well as to help determine where potential sediment-related impairments may exist.<br /><br /> Reference suspended-sediment transport rates at an effective discharge equal to the 1.5-year recurrence intervals have been developed for various ecoregions of the United States and include several stream basins in Mississippi. Preliminary analysis of historical USGS sediment and flow data for sites in these select basins indicate that there is a correlation between sediment yield at the effective discharge and certain basin characteristics, including basin slope and drainage area, and these relationships may improve the ability of water-resource managers to identify potentially impaired streams and set target sediment yields at more attainable levels.
Assessing and Predicting In-Stream Processes in the Catalpa Creek Watershed
Year: Authors: Ramirez-Avila J.J., Ortega-Achury S.L., Schauwecker T., Czarnecki J., Langendoen E.J., Martin J.L., Cartwright J., Veeder D.
Hypothesizing in-stream processes are important mechanisms driving sediment supply into the streams and an important portion of the sediment budget for the Catalpa Creek Watershed, this research will focus on the identification, assessment, evaluation and prediction of in-stream processes within the study watershed. To address the research objectives three studies are undertaken using a combination of methods including field reconnaissance and detailed data collection, laboratory analysis, and channel modeling. Modeling results can help to determine critical areas to be potentially considered for future management and restoration activities, as well as to optimize a design for a desired outcome and to understand what results might be expected. The project has been subdivided in three studies oriented to respond specific objectives related to the spatial variation and change of sediment loads, the occurrence of in-stream processes and the capability of the models to predict streambank erosion and instabilities for the study area. The project involves important collaborative efforts with MSU faculty members from other departments and institutes and from state and federal research and education institutions. The training of students with different levels of involvement has been of fundamental support to the performance of the project. Project results will be transferred to a broad group of academic, technical and research stakeholders, supported in collaboration with private, federal and state agencies.
Applied Use of Unmanned Aerial Vehicles in Surface Water Quality Protection
Year: Authors: Czarnecki J., Ramirez-Avila J., Schauwecker T., Langendoen E.J.
The objective of this research is to evaluate the accuracy of erosion calculations derived from Structure from Motion (SfM) captured with unmanned aerial vehicles (UAV) and determine the best practices for use of this technology for this purpose. The research project combines results from SfM digital surface models (DSM) with ground-truth measurements of erosion to determine the accuracy of this approach. Derived values were incorporated into existing models (e.g., BSTEM) to determine if SfM data were a valid model input. The result of this research is a scientific validation of the erosion calculations derived from DSM. The research serves as a proof-of-concept project to develop a method by which UAVs could be employed to identify, quantify, and monitor erosion in drainage channels and other eroded areas. This would enable federal, state, and local agencies to utilize this technology to more efficiently monitor, remediate, and regulate degradation of surface waters. Outputs from this research project include transfer of information on the appropriate data collection strategies for UAV-based erosion assessment, as well as best practices, along with methods, estimates of accuracy, and any necessary cautions. This data will be communicated to stakeholders through scientific exchange and interaction, in addition to the established University Extension network.
Study of Sediment and Nutrients in Pelahatchie Bay and Upland Mill-Pelahatchie Creek- Watershed
Year: Authors: Chao X., Bingner R.L., Zhang Y., Yasarer L.
Pelahatchie Bay is located in the northeast section of Jackson, the capital city of Mississippi. Its upland watershed, Mill-Pelahatchie Creek Watershed contains a high percentage of construction sites and developed areas, causing a lot of sediment and associated pollutants to discharge into the bay through runoff. In addition, sediment, nutrients, and other pollutants may also flow into Pelahatchie Bay from the upstream Pelahatchie Creek.<br /><br />This project studied the response of water quality in Pelahatchie Bay to the sediment and pollutant loads from upland watersheds. The hydrodynamics, sediment transport, and water quality processes were studied using numerical simulations. The Annualized Agricultural Non-Point Source (AnnAGNPS) pollutant loading watershed management model, developed at the USDA ARS, National Sedimentation Laboratory (NSL), was applied to simulate the loads of runoff, sediment and nutrients from the upland watershed. The simulated results were used as boundary conditions for CCHE, a free surface flow, sediment and water quality model developed at the National Center for Computational Hydroscience and Engineering (NCCHE), to simulate flow, sediment transport and water quality processes in the bay. The effectiveness of implemented best management practices (BMPs) in the upland watershed on the water quality in the bay were also evaluated.
Trend Analysis of Streamflow to Support Bay and Estuary Restoration in Gulf States
Year: Authors: Rodgers K.
The discharge of freshwater from rivers and streams to estuaries is important for biological and economic endpoints. The estuaries of the Gulf of Mexico represent one of the most diverse and important ecosystems in the United States. These systems are also heavily influenced by anthropogenic effects within upstream watersheds. Understanding systematic changes in streamflow can provide decision-support for water resources managers to help ensure that estuaries of the Gulf of Mexico receive the critical supply of freshwater needed. In 2016, the U.S. Geological Survey began an effort to characterize freshwater discharge in U.S. tributaries to the Gulf in support of the initiatives prioritized by the Gulf Coast Ecosystem Restoration Council. As part of this effort, daily mean streamflow data were aggregated to monthly, seasonal and annual means at 1,389 gaging stations for streams that drain to the Gulf of Mexico. These values were used to test for monotonic trends in streamflow using the non-parametric Mann-Kendall Trend test. Streamflow trends were synthesized by watersheds representing four-digit hydrologic-unit codes (HUC4). Initial analysis of monthly mean discharge at 28 gaging stations (the most downstream station in each of the 28 HUCs draining to the Gulf) indicate increasing trends at 14 percent (4 sites) of the sites and decreasing trends at 32 percent (9 sites) of the sites. Fifty-five percent of the sites indicated no trend in streamflow. A calculation of area based on land use in the 28 HUC4s does not indicate a dominant land use classification associated with increasing or decreasing streamflow trends. Future work will also evaluate trends in low and high flows, relate streamflow trends to changes in land use or other causal influences, and examine the relationship between streamflow trends and biological or economic endpoint within the Gulf of Mexico.
Evaluating Change in Intermittent Streams Monitored by the Mississippi Delta Nutrient-Reduction Strategy Efforts: Successes and Challenges
Year: Authors: Hicks M.B.
Evaluating the effectiveness of on-field implementation of agricultural best management practices (BMPs) to improve downstream water quality is a challenge due to seasonal and temporal fluctuations in streamflow and water chemistry and to the limited resources available to monitor these two variables. Yet consistent monitoring and evaluation of collected data is the ideal way to document water-quality changes. In 2010, the U.S. Geological Survey began monitoring in several small drainages in northwestern Mississippi as part of nutrient-reduction strategy efforts in the Mississippi Delta. Various BMPs were implemented to reduce sediment and nutrient runoff in the drainages. Water quality and streamflow were monitored for 5-10 years and data were evaluated and then correlated with observed changes in BMPs. Data analysis progressed in a two-step approach. First, exploratory analyses were completed to evaluate the general hydrologic and water-quality conditions of each site. Then, inferential analyses including tests of differences and equivalences were completed using bootstrapping or an assumed distribution based on the available data. Finally, a power analysis was completed to evaluate the minimum detectable change in water quality possible based on the collected data and to determine the ideal number of samples that need to be collected in the future for similar studies. An example of these data-analysis results will be presented for an intermittent tributary that drains into Bee Lake. This particular tributary has had several BMPs installed over the study period. The results of the analysis and "lessons learned" during monitoring, summarized as successes and challenges presented by this approach, will provide relevant information for forthcoming analyses and similar future studies in this area.<br /><br /><a href="/conference/pdf/matt_hicks2016.pdf">Download presentation</a>
Chitosan Nanoparticle Applications for Water/Wastewater Treatment
Year: Authors: Cook C.R., Gude V.G.
Chitosan is an abundant naturally occurring biopolymer originating from several microbial species as well as crustacean species, such as shrimp and lobster. This biodegradable polymer has been the subject of research for water treatment applications for more than three decades due to its excellent physical and chemical properties; however, modern processes have allowed for the creation of new, novel materials. Chitosan presently offers a myriad of potential through chemical coagulation and flocculation, antimicrobial properties, adsorption capabilities, nanofiltration, and more. Such new applications as chitosan gelations, membranes, grafted nanoparticles, and other functionality-driven variations allow greater efficiency and broader implications than ever before. This presentation will discuss some of the recent developments in chitosan nanoparticle research for potential applications in water and wastewater treatment.
Monitoring and Characterization of Water Resources in Priority Areas throughout Mississippi
Year: Authors: Banks J.
The Office of Land and Water Resources is charged with conserving, managing, and protecting the water resources of Mississippi. To help achieve this mission, the Monitoring Branch of the Water Resources Division was created in 2015 to monitor the quantity of the state's ground water and surface water resources. A primary goal for the Monitoring Branch is to characterizing the available water resources in prioritized areas throughout the state each fiscal year. Study areas vary in extent and are prioritized based on factors such as population, demand, and historical record. Prioritized areas are characterized based on the collection and compilation of data from multiple sources regarding current and historical ground water levels, base line water quality, and geology, among other things. The prioritized areas being studied for state fiscal year 2017 are Clarksdale, Starkville, Flowood/Brandon, and McComb.<br /><br /><a href="/conference/pdf/john_banks2017.pdf">Download presentation</a>
Office of Land and Water Resources: Permitting, Certification and Compliance Division Initiatives
Year: Authors: Hawkins C.
The Office of Land and Water Resources (OLWR) is responsible for the management of the water resources in Mississippi. § 51-3-1 of the Mississippi Code requires that the water resources of the state be put to beneficial use to the fullest extent of which they are capable, that the waste or unreasonable use, or unreasonable method of use, of water be prevented, that the conservation of such water be exercised. To achieve this requirement, the Permitting, Certification, and Compliance Division administers several programs and is undertaking several initiatives to improve our services. These initiatives include revision of the minimum conservation practices required to obtain a permit from the alluvial aquifer in the delta; expanded water use surveys and reporting tools; improved software for the review and processing of applications for issuance, modification and enforcement of surface and ground water use permits; monitoring of a ground water well network within national framework; and improved licensing and regulating water well contractors operating in Mississippi. OLWR strives to ensure that the use, storage, allocation, and management of water resources of the state be accomplished to the fullest yet sustainable extent possible and that water used in Mississippi complies with applicable permit regulations.<br /><br /><a href="/conference/pdf/chris_hawkins2017.pdf">Download presentation</a>
Overview of Recent Dam Failures and Incidents
Year: Authors: Myers D.
The goal of the Dam Safety Program is to protect people and property from the damaging consequences of catastrophic dam failures. Each year, there are several dam failures in Mississippi and many other dams are breached under controlled conditions to avoid the possibility of a sudden failure. Some dam failures in the state have caused significant property damage, but there have been no fatalities in Mississippi attributable to a dam failure. Our goal is to provide sufficient oversight of the operational safety and structural integrity of dams in Mississippi to minimize the possibility of a life threatening catastrophic failure occurring at a dam that falls under our jurisdiction.<br /><br /> Since the start of the Mississippi Dam Safety program in 1978 there have been approximately 111 reported dam failures and incidents. This presentation will provide a general overview of dam failure modes, a review of recent dam failures and incidents, and lessons learned.<br /><br /><a href="/conference/pdf/dusty_myers2017.pdf">Download presentation</a>
Office of Land and Water Resources: Overview of Mississippi's Participation in the National Ground-Water Monitoring Network
Year: Authors: Sorrell K.
Water is a vital resource, and water resource management is a high priority concern at both the state and federal level. The National Ground-Water Monitoring Network (NGWMN) was established by the Subcommittee on Ground Water (SOGW) in 2007 to monitor ground-water availability in major aquifers and aquifer systems across the United States. The goal of this network is to collect and compile groundwater level and quality data in a common shareable format so that long term trends can be identified and used to aid in current and future water-resource management decisions. The Office of Land and Water Resources (OLWR), a division of the Mississippi Department of Environmental Quality (MDEQ), has maintained a network of observation wells in the state of Mississippi with recorded water level data dating back to 1930. In 2015, the OLWR began work to incorporate its existing observation well network into the NGWMN database. Participation in this program has allowed the OLWR an opportunity to consider new approaches to data collection, data management, and water resource management by collaborating with other states to develop the network.
Irrigation Water Management Strategies that Improve Crop Yield and/or on Farm Profitability
Year: Authors: Krutz L.J., Pickelmann D., Atwill R., Leininger S., Bryant C., McNeal J., Wood W., Henry M.
The Row-crop Irrigation Science Extension and Research (RISER) program has demonstrated how Irrigation Water Management (IWM) practices including computerized hole selection, surge irrigation, soil moisture sensor (SMS) technology, and alternate wetting and drying (AWD) reduces irrigation water use up to 40% while improving profitability by $40/acre. However, very few Mid-South irrigators are using IWM practices. The objectives of this session are to 1) illustrate how computerized hole selection and surge irrigation improves irrigation application efficiency; 2) describe how SMS technology improves irrigation scheduling decision for initiation and termination; 3) inform practitioners how AWD impacts water use, yield, weed control, and N uptake 4) examine on-farm case studies where IWM practices significantly improved corn, soybean and rice yield/profitability.<br /><br /><a href="/conference/pdf/jason_krutz2017.pdf">Download presentation</a>
Use and benefits of weirs for irrigation water supply, ecological stream restoration, and aquifer recharge
Year: Authors: Johnson D.R.
Currently groundwater is the primary source of irrigation water supply in the Mississippi Delta, and aquifer levels are declining. In-stream weirs offer a relatively inexpensive means to increase surface water supply. Several factors which affect the cost of weirs will be examined. In addition, the potential benefits of weirs for stream restoration and aquifer recharge will be addressed. Finally, permitting issues will be briefly addressed.<br /><br /><a href="/conference/pdf/david_johnson2017.pdf">Download presentation</a>
Groundwater Transfer & Injection: Progress toward a managed aquifer recharge option for sustainable groundwater supply
Year: Authors: Rigby J.R.
Sustainable use of the Mississippi River Valley Alluvial Aquifer (MRVAA) for irrigation will require increased efforts to manage and enhance aquifer recharge to meet demand. One scenario for aquifer management involves the development of a groundwater transfer and injection project to move water from the Tallahatchie River to the central Delta. Such a project relies fundamentally on adequate hydraulic connection between the Tallahatchie River and the MRVAA to supply the required water. This presentation will review the conceptual model of the groundwater transfer and injection option and the research necessary to determine its feasibility. Preliminary data on stream-aquifer interactions and groundwater injection from Leflore and Sunflower Counties collected in collaboration with U.S. Geological Survey and Mississippi Department of Environmental Quality will be discussed with implications for larger pilot studies.<br /><br /><a href="/conference/pdf/j_rigby2017.pdf">Download presentation</a>
Those who say it can't be done are often interrupted by somebody doing it
Year: Authors: Palmer, Jr. J.I.
The Yazoo-Mississippi Delta Joint Water Management District (YMD) was established in 1989 by the Boards of Supervisors of the seventeen counties or partial counties comprising the Mississippi Delta physiographic region. The members of the YMD Board of Commissioners (Board) are appointed by the member counties, and the headquarters office of the agency is located in Stoneville, Mississippi. The Executive Director, Deputy Director, and Financial Officer serve as the senior leadership team <blockquote> Mississippi law recites:<br /><br /><em> It is the policy of the Legislature that conjunctive use of groundwater and surface water shall be encouraged for the reasonable and beneficial use of all water resources of the state. The policies, regulations and public laws of the State of Mississippi shall be interpreted and administered so that, to the fullest extent possible, the ground and surface water resources within the state shall be integrated in their use, storage, allocation and management.</em></blockquote> Thus, the principal mission of YMD is to develop water resources management policies, plans, and projects that promote and ensure sustainable surface water and groundwater supplies for the Delta's expanding agricultural economy. In the planning arena, YMD operates under delegation of authority from the Mississippi Commission on Environmental Quality, which approved YMD's current water resources management plan in 2006. In the permitting arena, YMD operates under delegation of authority from the Environmental Quality Permit Board to receive and review applications for permits to utilize surface water and groundwater and make recommendations, through the Board, to the Mississippi Department of Environmental Quality regarding the issuance, denial, revocation, or modification of such permits. <br /><br /> Over the twenty-eight years since its formation, YMD has sponsored the construction of a number of surface water and groundwater projects to maintain and enhance agricultural water supplies, support fisheries, waterfowl, and wildlife habitat, and achieve environmental restoration, in general. The largest of these projects, built in 2005, is a well field that provides groundwater for low flow augmentation in the upper Sunflower River watershed during the irrigation season in the dry weather months of the year from late Summer through late Fall. This presentation will cover both the YMD projects that have been completed over the years and others that the YMD Board is now actively supporting, promoting and pursuing.
Essential Components for Custom Water Management Software Utilizing Modern Web Standards and the Amazon Cloud
Year: Authors: Gartrell B., Bailey J., Collier A.
This talk will discuss the components necessary for custom water management software that utilizes modern web and cloud technology, as well as spatial enterprise Relational Database Management Systems (RDBMS) and the latest NoSQL databases in the Cloud. Water managers need their information capture and display methods modernized to keep pace with today's technology. If your workflow involves paper forms, it is time to modernize. However, don't simply settle for where the industry was a decade ago (e.g. antiquated technologies such as Access and Silverlight). <br /><br /> Utilizing modern technology will realize the following advances: <ol><li>The database is no longer fragmented into multiple pieces of outdated software and data repositories. </li> <li>Cloud-based enterprise RDBMS eliminates costly infrastructure and time spent doing backups, upgrades, and maintenance of hardware and software. </li> <li>Data are readily available and backed up across multiple data centers, so local disaster recovery is instantly achieved. </li> <li>With web mapping tied to dashboard and reporting systems, all information is connected. </li> <li>Having paper forms integrated as web forms means that all data is collected directly in the Cloud database, resulting in cleaner data and real-time utilization. </li> <li>The latest web technology is used to give the most performant and standards based approach. </li> <li>The system can be scaled and load balanced to achieve a consistent experience given a small or large number of concurrent users.</li> <li>Content can be accessible across mobile/tablet/PC platforms.</li> <li>The open architecture of the software is maintainable for years to come.</li></ol>
Community-Based Research Strategies to Analyze Risk of Lead Contamination in Public Water Supplies in the Mississippi Delta
Year: Authors: Fratesi M.A., Woo L., Green J.J., Otts S.S., Janasie C., Rhymes J., Thornton C., Avula B.
This project includes community-based participatory research and an assessment of residential drinking water supplies and water supply infrastructure in the Mississippi Delta. Additionally, we aim to assess multiple social science approaches to engage stakeholders and influence policy on the current state of lead contamination in drinking water in Mississippi. The 2016-2017 cohort of students enrolled in the Tri-County Workforce Alliance and their parents served as our initial community partners. The participants came from four counties (primarily Coahoma) and 14 municipalities and all reported being on public water systems (e.g. not wells). Participants collected their home drinking water (first catch of the day from kitchen sink, cold water) and samples were analyzed for pH and lead concentrations. Sixty-eight of the 87 distributed bottles (78%) were returned. The pH of the drinking water samples ranged from 7.04-8.23. Notably, lower pH is associated with higher potential to leach lead. Of the samples tested so far from the Delta cohort, only 20 of the samples had lead concentrations above the detection limit, with the highest concentration being 3.45 ppb. All concentrations were well below the EPA 15 ppb action level. Letters were sent to each participant notifying them of their water results. The study is ongoing: demographic data is being analyzed for risk factors associated with lead detects; water sampling data from public water systems is being collected and analyzed; and additional community cohorts are being engaged. For example in the cohort, 85% of the residences were houses (vs. apartments or mobile homes) and 47% of the respondents who estimated the age of their home indicated that it was built before 1985. Ultimately, this project has the potential to help safeguard public health because survey and sampling results will help assess the risks of lead contamination in the Mississippi Delta, assist with the identification of lead service lines and lead plumbing within the distribution systems, and design and guide scalable research and outreach efforts to minimize lead exposure through use of filters and/or behavioral changes.
Drinking Water Supplies- How is Your Tap Water Regulated?
Year: Authors: Janasie C.
In the past, many Americans took the safety of their drinking water for granted. However, recent national news stories about the quality of drinking water have brought water quality to the forefront of many people's minds. Most noteworthy have been the stories of lead contamination in the drinking water supplies in cities like Flint, MI and Jackson, MS. In addition to lead contamination, additional issues with drinking water supplies have also appeared. For instance, in 2014 a harmful algal bloom forced Toledo, OH to issue a two-day ban on the use of the city's tap water, which had tested positive for the toxin microcystin. Further, lawsuits have emerged concerning the drinking water supplies in cities such as New York, NY and Des Moines, Iowa. Litigants in those cases claim there are Clean Water Act violations in the delivery of water to households in the respective cities.<br /><br /> This talk will focus first on how drinking water supplies are regulated in the United States. Next, the talk will review the requirements of the Safe Drinking Water Act, as well as what happens when a drinking water supply exceeds a contaminant level under the Act, such as when the lead level was exceeded in Jackson, MS. In addition, the talk will discuss the role that other environmental statutes, like the Clean Water Act, play in the regulation of our drinking water supplies. Finally, the talk will consider what changes may be coming to the regulation of drinking water in the United States.<br /><br /><a href="/conference/pdf/catherine_janasie2017.pdf">Download presentation</a>
Mississippi Private Well Owner Demographics and Characteristics
Year: Authors: Barrett J.R.
Mississippi citizens who acquire their drinking water from private wells do not have the luxury of knowing the quality of their drinking water on a regular basis unless they are making the effort to have their water screened and tested. Approximately 90% of Mississippi citizens are served by one of the over 1,200 public water systems which provide safe reliable water under the regulatory enforcement of the Mississippi State Department of Health-Bureau of Public Water Supply. Private well owners are free to operate and maintain their wells because there is no regulatory oversight. For some private well owners, this freedom is welcome but others want to know the quality of their drinking water.<br /><br />No demographic data about private well owners has been compiled since the 1990 census. At Mississippi State University Extension workshops for the Mississippi Well Owner Network in which private well owners were able to have their well water screened for bacteria, demographic data was collected. This presentation will compare demographic data and characteristics of current private well owners with those from the 1990 census as well as compare to overall Mississippi demographic data. The concluding data can be utilized to better understand and serve Mississippi private well owners.<br /><br />This study should be of interest to representatives of local municipal water systems, local communities, and rural water associations for potential expansion of their water systems. The expansion of a public water system may achieve multiple goals. Additional customers generate more revenue for the public water system, as well as provide a larger customer base in which to spread costs. The regulatory oversight of public water systems should promote and produce a safer drinking water supply for Mississippi residents.<br /><br /><a href="/conference/pdf/jason_barrett2017.pdf">Download presentation</a>
Cost Analysis of Water Management Scenarios for the Mississippi Delta
Year: Authors: Falconer L., Tewari R., Johnson J.
The objective of this study is to provide the Mississippi Department of Environmental Quality with a report comparing the cost of reduced pumping or increase in recharge per acre-foot in the Mississippi River Valley Alluvial Aquifer as a result of 5 proposed groundwater management alternatives with scenarios. It is important to note that the cost data available for some of the alternatives are more detailed and current than the data for others. The cost data for the RISER and the Tailwater Recovery and Onfarm Storage scenarios are detailed, current, and based on recently implemented projects and practices. The cost estimates for the Enhanced Aquifer Recharge scenario are detailed and based on research on current materials and construction and ancillary costs for a project with similar components, but no comparable project has actually been built. The cost estimates for the Tallahatchie-Quiver Intra-basin Transfer scenarios are based on a U.S. Army Corps of Engineers (USACE) report issued in September, 2016. The cost estimates for the Instream Weir scenarios are based on itemized costs provided by USACE personnel.<br /><br /> Preliminary results indicate that at 33%, 66% and 100% adoption rates in the service area for the Instream Weir alternative scenarios, this alternative provides the lowest cost per acre foot per acre-foot in reduced pumping from the aquifer.<br /><br /><a href="/conference/pdf/larry_falconer2017.pdf">Download presentation</a>
Water Availability in the Mississippi Delta: Initial Assessment of Alternative Water-Supply Scenarios
Year: Authors: Barlow J.R., Haugh C.J.
In an effort to better understand the impacts of different water-management scenarios on water availability and to identify additional monitoring needs in the Mississippi Delta, the U.S. Geological Survey and the Mississippi Department of Environmental Quality are collaborating to update and enhance an existing regional groundwater-flow model. As a result of this collaboration, the model has been updated through 2013 with the most recent water-use data, precipitation and recharge data, and streamflow and water-level observation data. The updated model has been used to evaluate selected alternative water-supply scenarios in order to assess relative impacts to the alluvial aquifer and identify data needs for future groundwater management modeling. Alternative water-supply options assessed to date include: 1) irrigation efficiency; 2) tailwater recovery and on-farm storage; 3) weirs for surface-water augmentation; 4) inter/intra-basin transfers; and 5) groundwater transfer and injection. A relative comparison approach was used to calculate the simulated water-level response due to each scenario. Water-level response is the difference between water-levels simulated by the alternative-supply scenario and those simulated by a base case or "no action" scenario. Water-level response in the alluvial aquifer varied for each scenario based on the location and magnitude of the implemented alternative-supply option. These initial model results will serve as a starting place to develop and assess conjunctive water-management-optimization scenarios as well as improve and enhance current and future monitoring activities within the Delta.<br /><br /><a href="/conference/pdf/jeannie_barlow2017.pdf">Download presentation</a>
Coupling Modeling with Monitoring to Assess Water Availability in the Mississippi Alluvial Plain
Year: Authors: Kress W.H., Clark B., Barlow J.
The Mississippi Alluvial Plain (MAP) is one of the most important agricultural regions in the United States, and crop productivity relies on groundwater irrigation from a system that is poorly understood. Groundwater use from the Mississippi River Valley alluvial aquifer has resulted in substantial groundwater-level declines and reductions in baseflow in streams within the MAP. These impacts are limiting well production and threatening future water availability for irrigation in the region.<br /><br /> Accurate and ongoing assessments of water availability in the MAP region are critically important for making well-informed management decisions about sustainability, establishing best practices for water use, and identifying predicted changes to the regional water system over the next 50-100 years. To provide stakeholders and water-resource managers with information and tools to better understand and manage available water resources within the MAP, the U.S. Geological Survey (USGS) initiated a regional water availability project funded by the Water Availability and Use Science Program (WAUSP). The MAP project couples modeling with monitoring to improve the characterization of the alluvial aquifer system in an existing numerical-groundwater-simulation model. The premise of the investigation is to evaluate the existing groundwater model and produce an estimate of the uncertainty of the model inputs, such as hydraulic conductivities, storage, streams, recharge, and water use. Based on the uncertainty results, additional data are collected (monitoring) to improve the model. After which, the uncertainty will be estimated again, and the process will be repeated as necessary. For example, initial uncertainty results indicated that better knowledge of streambed conductances could improve the precision of simulated groundwater levels. In response to this data need, waterborne geophysical data were collected along 180 km of streams in the Mississippi Delta. The geophysical data identified areas of coarse- and fine-grained material in the streambed that may control the amount of water passing between the alluvial aquifer and the stream. The results of the geophysical investigation can be used to adjust the relative streambed conductance (increase for coarse-grained sediment and decrease for fine-grained material) and input into the numerical model to determine if the precision of simulated water levels improve. Through this iterative method of modeling and monitoring, a more dynamic "living" numerical model will be available to more accurately represent groundwater flow in the system. The MAP groundwater model can then be used to help manage the water resource evaluate potential future effects of water-use changes, conservation practices, construction of diversion-control structures, or climate change.<br /><br /><a href="/conference/pdf/wade_kress2017.pdf">Download presentation</a>
Delta Sustainable Water Resources Task Force Update
Year: Authors: Whittington K.
Groundwater levels in the aquifer used for irrigation in the Mississippi Delta are declining as irrigation demands have increased. By law, the Mississippi Department of Environmental Quality (MDEQ) is charged with conserving, managing, developing, and protecting the state's water resources. MDEQ is working with those in the Delta through the Delta Sustainable Water Resources Task Force to identify solutions. A Voluntary Metering Program is being implemented to get accurate withdrawal information and irrigation water management practices proven to save water, time, and money are being promoted. Progress must be made now with voluntary measures while all options continue to be investigated.<br /><br /><a href="/conference/pdf/kay_whittington2017.pdf">Download presentation</a>
Research Program at the USDA-ARS National Sedimentation Laboratory: Addressing Agricultural and Natural Resource Management
Year: Authors: Locke M.A.
The USDA-ARS National Sedimentation Laboratory, Oxford, MS, ("Sed Lab") has served for 50 years as a center for research on sediment and erosion issues and is currently the lead USDA-ARS facility addressing (1) watershed erosion and sedimentation processes, and (2) watershed ecological functions as impacted by agricultural practices. The Sed Lab consists of two research units: (1) Water Quality and Ecology, and (2) Watershed Physical Processes. The research program emphasizes interdisciplinary studies dealing with physical, chemical, and biological processes related to natural resources in agricultural watersheds, and assessing strategies for sustaining and enhancing the integrity and function of agro-ecosystems. Specific topics of study include: (1) soil erosion, transport and deposition of sediment in watersheds including stream stability and bank protection; (2) agricultural practice and stream structure impacts on water quantity, water quality, and ecosystem services; (3) movement and fate of chemicals within the landscape; (4) ecosystem integrity of streams and adjacent riparian zones, lakes and wetlands; and (5) processes controlling surface and groundwater movement. The NSL also serves as the lead research facility in the Lower Mississippi River Basin for the USDA-ARS Long Term Agro-ecosystem Research (LTAR) network.
Economic analyses of tailwater recovery systems
Year: Authors: Omer A.
Tailwater recovery (TWR) systems are being implemented on agricultural landscapes to reduce nutrient loss and save water on the landscape for irrigation. These systems are a large financial investment for both government agencies (United States Department of Agriculture Natural Resources Conservation Service) and private producers with total costs ranging from $400,000-900,000. Although economic analyses of TWR systems have been modeled, analyses of implemented TWR systems have yet to be completed. Economic studies are necessary to guide adaptive management of conservation funding for appropriation in methods with the greatest return. Therefore, an analysis was conducted on the costs and benefits of TWR systems. Net present values (NPV) and benefit to cost ratios (BCR) of TWR systems were used to compare the benefits to the costs. Three discount rates of 3, 7, and 10% were used on both rented and owned land schemes. Five TWR system scenarios were used in the investigation including dryland, irrigated, irrigation improvements, TWR systems, and TWR systems with external benefits of sediment loss mitigation. NPV and BCRs were positive and greater than one for TWR systems if producers owned the land but remained negative or less than one if land was rented. Beyond improvements to irrigation infrastructure, farms with a TWR system installed lost NPV of $51 to $328 per ha. The range of mean total cost to reduce solids using TWR systems was $0 to $0.77 per kg; P was $0.61 to $3,315.72 per kg; and N was $0.13 to $396.44 per kg. The range of mean total cost to retain water using TWR systems was $189.73 to $628.23 per ML, compared to a range of mean cost of groundwater of $13.99 to $36.17 per ML. Compared to other conservation practices designed to reduce solids and nutrients, TWR systems are one of the least expensive ways to reduce solid losses from the landscape but remain an expensive way to reduce nutrient losses. Using TWR systems to provide an additional source of irrigation water yields a wide range in costs from less expensive than water efficiency conservation practices to similar to the high costs of practices such as desalination. Therefore, TWR systems may be a more expensive conservation practice to retain nutrients and water on the agricultural landscape than other solutions.
Summary of tailwater recovery system efficiencies as a conservation practice
Year: Authors: Omer A.
Water conservation practices are being widely implemented to alleviate sediment and nutrient losses from agricultural land and unsustainable groundwater use for irrigation. Tailwater recovery (TWR) systems are conservation practices being implemented to collect and store runoff to reduce nutrient losses and provide a source of irrigation water. This research is focused on evaluating TWR systems through the following actions: 1) investigate ability to reduce solids and nutrients delivery to downstream systems; 2) determine the potential to irrigate water containing solids and nutrients; and 3) quantify a water budge for TWR systems. Tailwater recovery systems did not significantly reduce concentrations of solids and nutrients; however, loads of solids, P, and N were significantly reduced by 43%, 32% and 44%, respectively. Mean nutrient loads per hectare available to be recycled onto the landscape were 0.20 kg ha<sup>-1</sup> P and 0.86 kg ha<sup>-1</sup> N. Water budget analyses show these systems save water for irrigation, but were inefficient. Mechanistically, TWR systems retain runoff on the agricultural landscape, thereby reducing the amount of sediment and nutrients entering downstream waterbodies and provide an additional source of water for irrigation; however, more cost-effective practices exist for nutrient reduction and providing water for irrigation.
Multiple Benefits Provided by an On-Farm Water Storage System in East Mississippi
Year: Authors: Tagert M.L., Paz J.O., Karki R., Perez-Gutierrez J.D.
A growing number of farmers in East Mississippi have been interested in implementing irrigation to increase yields and reduce risk during periods of infrequent rainfall. However, it is not economically feasible, or even possible in some areas, to use groundwater for irrigation in East Mississippi. Farmers must instead rely solely on surface water for irrigation. Some farmers are able to obtain a permit to withdraw surface water from a nearby stream, but this source also carries the risk of being inadequate in times of sparse rainfall during the growing season. On-farm water storage (OFWS) systems are a better solution for providing water for irrigation in East Mississippi, and these systems are being implemented by producers in this region. After installation of an OFWS system, the pond is commonly gravity-fed by rainfall-runoff collected throughout the year, and fields are typically irrigated using sprinkler irrigation. Storage ponds in East Mississippi are larger than those used conjunctively with groundwater, because they must hold enough water to irrigate a given area throughout the entire growing season. This presentation will discuss the multiple benefits provided by an OFWS system in the Middle Tombigbee-Lubbub watershed (HUC 0316106) in East Mississippi, including reduction of downstream nutrient and sediment runoff and the quantity of surface water provided for irrigation which subsequently increased crop yields.
On-Farm Water Storage (OFWS) as a Tool to Reduce Risk
Year: Authors: Agyeman D., Williams B., Coble K., Tagert M.L., Parman B.
Though irrigation can offer producers many advantages such as reducing potential losses due to uncertain rainfall, in some areas of the Southeast irrigation options for agricultural crops are limited. For example, in East Mississippi access to groundwater resources is impractical, with well depths often exceeding 1,000 feet and prohibitively high drilling costs. As a result, producers are gradually resorting to the use of on-farm water storage systems (OFWS) to recapture irrigation runoff and rainfall for later use for irrigation. Previous research has confirmed reduced groundwater withdrawal and downstream flow of nutrients are some advantages that come with OFWS, but few studies have focused on the economic profitability of this system. This article employs a stochastic benefit-cost analysis to analyze the net returns of irrigating from an OFWS using a center pivot irrigation system (CPIS) compared to a rain-fed production system for corn and soybean in the Southeast while also incorporating risk in the form of stochastic prices and yields. Preliminary findings indicates that investing in an OFWS for irrigating purposes can increase producers returns significantly compared to depending on rainfall. As expected increase in interest rates reduces the net present value of making such an irrigation investment and this is more evident when interest rates are above 7%. The use of OFWS becomes more attractive when revenue generated is protected under crop insurance. As coverage levels increases the net present value of investing in an OFWS increases well above that rain-fed production at lower interest rates, however there's over 60% chance of rain-fed production been more profitable than irrigating at 70%, 75%, 80% and 85% coverage levels when discount rates are over 9%.
CHANGE is Coming: An Introduction to the Next Generation of Hydraulic Modeling
Year: Authors: Hendon D.L.
Recent developments in hydraulic modeling and 3D computer visualization provide engineers, scientists, CFMs and other users with the tools for a more comprehensive understanding of complex flow patterns that are commonly associated with river crossings and in coastal environments. These tools help locate and illustrate patterns of flow, water surface elevations, depth, velocity, and shear stress. The proper use of these tools allows a more realistic estimation of hydraulic conditions (e.g., scour); floodplain impacts (e.g., FEMA floodplain); aquatic and terrestrial habitat impacts; and extreme weather event scenarios. There is a shift coming in our professions to move from one-dimensional models, such as HEC-RAS, to two-dimensional models. This presentation will cover the differences, applications, and visualizations that are associated with this change. Attendees will be provided an introduction to these new tools so they may have a better understanding of what they look like, what they can do, how they work, and how to use the results.<br /><br /><a href="/conference/pdf/don_herndon2016.pdf">Download presentation</a>
Groundwater availability of the Coastal Lowlands aquifer system - refinement of a regional-numerical model
Year: Authors: Clark B., Duncan L., Foster L., Kress W.
The Coastal Lowlands Aquifer System (CLAS), a large, regional aquifer comprised of multiple hydrogeologic units, is located along the Gulf of Mexico from the Texas/Mexico border through the Florida panhandle. Groundwater withdrawals from the aquifer system are primarily for public supply, irrigation, and self-supplied industry. As withdrawals from the system have increased, some areas along the Gulf have experienced water-level declines, saltwater encroachment, and land subsidence. The U.S. Geological Survey (USGS), as part of the Water Availability and Use Program, is developing a regional groundwater-flow model (~99,000 square miles) to simulate past, present, and projected conditions and to improve understanding of groundwater availability in the CLAS. The model incorporates a refined hydrogeologic framework, as well as improved estimates of aquifer recharge, water use, and groundwater-surface water exchange. <br /><br /> The refined hydrogeologic framework builds on work from the 1980s and 1990s for the USGS Gulf Coast Regional Aquifer System Analysis, and our agency is working with other locate, state, and Federal agencies to integrate data and knowledge gained since the original model was created. Improved land-surface-altitude data and methods to estimate recharge, additional driller's log information, and data extracted from multiple smaller-scale models are a few of the sources for new information. After incorporation of these data and other model parameters, initial estimates of uncertainty will be calculated to help guide additional model refinement as an iterative process. The resultant model (or model ensemble) will quantify groundwater resources in the system and provide uncertainty ranges to better evaluate the predictive capability of future simulations.<br /><br /><a href="/conference/pdf/brian_clark2016.pdf">Download presentation</a>
Numerical Modeling of Flow Circulation and Chlorophyll Concentration in an Oxbow Lake in the Mississippi Delta
Year: Authors: Chao X., Jia Y., Locke M., Lizotte R.
The Mississippi Delta is one of the most intensively farmed agricultural areas of the United States. The quality of surface water resources in this area are particularly vulnerable due to excessive sediment, nutrients, and pesticides transported from upland watershed. <br /><br /> Beasley Lake watershed (BLW) located in Sunflower County of the Mississippi Delta, was selected as one of the Conservation Effect Assessment Project (CEAP) benchmark watersheds to assess environmental benefits derived from implementing USDA conservation programs. The loads of flow, sediment and water quality from the upland watershed were measured by the USDA-ARS National Sedimentation Laboratory (NSL). The weekly or biweekly samples of suspended sediment, nutrients, chlorophyll, bacteria, and other selected water quality variables in the lake were also collected and analyzed. Field measurements show that the concentrations of nutrients and sediment of the lake are greatly affected by the loads of upland watershed. <br /><br /> A water quality model, CCHE_WQ has been developed by National Center for Computational Hydroscience and Engineering, and applied for predicting the distributions of nutrient, phytoplankton, dissolved oxygen, etc., in natural lakes. In Beasley Lake, wind shear is the major driving force for flow hydrodynamics. The flow circulations were simulated using CCHE hydrodynamic model, and the CCHE_WQ model was applied to simulate the concentration of chlorophyll in the lake. The simulated results were generally in good agreement with field measurements. The sensitivity scenarios show that the lake primary productivity is mainly limited by suspended sediment concentration, while it is less sensitive to concentrations of nitrogen and phosphorus.<br /><br /><a href="/conference/pdf/xiaobo_chao2017.pdf">Download presentation</a>
Estimating Impacts of Future Rainfall Change on Stream Flow and Sediment Load in Lower Yazoo River Watershed Using BASINS-HSPF-CAT Modeling System
Year: Authors: Ouyang Y., Feng G., Parajuli P.B.
Climate change over the past several decades has resulted in shifting rainfall pattern and modifying rainfall intensity, which has, in turn, exacerbated stream flow and sediment load and imposed uncertainties to these processes. This study projected impacts of potential future rainfall variations on stream flow and sediment load from Lower Yazoo River Watershed (LYRW) in Mississippi using the BASINS (Better Assessment Science Integrating Point and Nonpoint Sources)-HSPF (Hydrological Simulation Program-FORTRAN)-CAT (Climate Assessment Tool) modeling system. The HSPF model was calibrated and validated with existing measured data prior to its applications. Several simulation scenarios were then performed to investigate impacts of different rainfall rates and storm intensities on stream discharge and sediment load from the LYRW outlet. Simulations showed that an increase in rainfall rate and intensity have resulted in dramatically increases in stream discharge and sediment load for the simulation conditions used in this study. A potential future wet climate has much greater impacts on hydrological processes and sediment load than those of a potential future dry climate at the LYRW. The coupled CAT-HSPF model is a useful tool to modify historical rainfall data to project future rainfall impacts on watershed hydrological processes due to climate change.
Hancock County Marsh Living Shoreline Project
Year: Authors: Wyatt M.
The Hancock County Marsh Living Shoreline project will provide for construction of up to 5.9 miles of living shoreline. In addition, approximately 46 acres of marsh will be constructed to protect and enhance the existing shoreline, and 46 acres of subtidal oyster reef will be created in Heron Bay to increase secondary productivity in the area. Located between Bayou Caddy and the mouth of the East Pearl River, the project area falls within the 20,909-acre Hancock County Marsh Preserve. This complex, one of the largest in Mississippi, is part of the Pearl River estuary in the western Mississippi Sound and managed as part of the Mississippi Coastal Preserves Program. Anticipated outcomes for the project include shoreline erosion reduction, creation of habitat for oysters and other secondary productivity, and the protection and creation of marsh habitat. The National Oceanic and Atmospheric Administration (NOAA) is partnering with the State of Mississippi on this project which has been funded by the Natural Resource Damage Assessment (NRDA) Trustee Council.<br /><br /><a href="/conference/pdf/marc_wyatt2017.pdf">Download presentation</a>
Identification and evaluation of potential impacts of onsite wastewater treatment systems in decentralized communities within the Jourdan River waters
Year: Authors: Rainey B.N., Gude V.G., Truax D.D., Martin j.L.
Assessment of water and wastewater quality is crucial to safeguard public health and the environment. However, water quality data on fresh and marine waters in the Mississippi coastal region, especially in the Jourdan River watershed, are still sparse and uncoordinated. Therefore, monitoring these parameters is important for the assessment of the environmental and public health impacts on these water bodies. This research is concerned with the water quality of tributaries in the Jourdan River watershed that could be potentially impacted by wastewater discharges from onsite treatment systems in the surrounding small communities. The tributaries monitored during this study (Orphan Creek, Bayou Bacon, and Bayou La Terre) are not currently monitored by the Mississippi Department of Environmental Quality (MDEQ), but feed directly into the Jourdan River. Seven small communities surrounding these tributaries were identified to evaluate any possible contribution to the water quality impairment in the Jourdan River. Eight sampling locations were selected to evaluate these water quality parameters at upstream and downstream points of these communities. The water quality parameters being monitored during the study were defined on the basis of total maximum daily load (TMDL) reports for monitored waters in the watershed and common nutrient contaminants present in wastewater effluent. Current wastewater treatment and management practices and their impacts on these receiving water bodies were assessed for the representative communities. This presentation will discuss the preliminary evaluation of the water quality parameters and a present perspective on the local water quality issues of the watershed.
Round Island Marsh Restoration
Year: Authors: Tracy S.
The Utilization of Dredge Material for Marsh Restoration in Coastal Mississippi Project was funded by the National Fish and Wildlife Foundation (NFWF) in November 2014. Over many decades, priority bays on the Mississippi Gulf Coast have experienced significant impacts due to shoreline erosion, storm damage, and alterations to sediment transport, contributing to the loss of thousands of acres of tidal marsh habitat. In the past, most dredge material has been disposed of offshore or in upland dredge disposal areas. This project advances Mississippi's beneficial use program to facilitate a cost-effective, sustainable approach to restoring and protecting significant coastal marsh and bay shorelines. An example of one of these restoration efforts is located in Pascagoula, MS at the Round Island Coastal Preserve. Over 200 acres of marsh were created using dredge material provided by the U.S. Army Corps of Engineers from the Pascagoula Channel. This marsh will create habitat for living coastal and marine resources, reduce erosion along bay shorelines, and improve water quality.<br /><br /><a href="/conference/pdf/sarah_tracy2017.pdf">Download presentation</a>
Oyster Restoration and Management
Year: Authors: Young A.
The Oyster Restoration and Management project was funded by the National Fish and Wildlife Foundation (NFWF) in November 2015. Oyster restoration is a major priority for the state of Mississippi due to oysters' importance to the area's ecology and to the state's economy. The project consists of five components: experimental cultch development, contaminated cultch assessment of the Mississippi Sound, environmental characterization including water quality and benthic mapping, oyster gardening, and a hydrodynamic model of the Lower Pearl River/West Mississippi Sound. These studies will contribute to the technical due diligence that will inform oyster restoration in Mississippi and help to ensure sustainability and success of future investments.<br /><br /><a href="/conference/pdf/alina_young2017.pdf">Download presentation</a>
An Economic Analysis of Agricultural Crop Production in the Mississippi Delta Under Alternative Nutrient Management Strategies
Year: Authors: Spencer D.S., Barnes J.N., Coatney K.T., Parman B.J., Coble K.H.
Several recent studies have examined how excess nutrient runoff from nitrogen and phosphorous have caused environmental damage in the United States. Perhaps the most significant is the hypoxia zone in the Gulf of Mexico. As a result, regulation of these nutrient levels has emerged as an important step toward environmental stewardship, yet this has been an uneven process. Some states have developed strict regulations to decrease nutrient runoff, but the majority of states have favored broader goals of reducing nutrient runoff using best management practices (BMPs) instead of strict regulations. <br /><br /> This presentation will showcase the empirical results and methodology used to examine the economics of alternative nutrient management strategies that can be used at the farm level to meet alternative standards for nitrogen and phosphorous runoff. We explain how we used a new methodological approach to understand alternative production practices and nutrient management strategy economics from a farm level perspective. The Agricultural Policy and Environmental eXtender (APEX) biophysical simulation model is used along with enterprise budgets to understand the cost impacts of alternative management practices and water quality standards in the Mississippi Delta.
Policy dimension of adopting wetlands assimilation to increase the NPDES compliance rates for municipal wastewater plants in Mississippi
Year: Authors: Ko J.Y., Day J.W.
The Clean Water Act has been contributing to water quality improvement and enhanced ecological integrity of natural ecosystem in the United States. However, water pollution driven by poorly treated municipal wastewater still has been significant deterrent factor in achieving the goals of the Clean Water Act, especially in the economically depressed Southern Region, causing harms to the human health, and the aquatic ecosystems. Academicians and government officials have advocated incorporating ecosystem services as a tool to increase compliance rates of the environmental regulation. <br /><br /> Economically poor communities across the Southern Region show poor compliance records of the NPDES regulation. For example, as of 2008, the compliance rate among the 1,437 NPDES permits of the wastewater treatment plants in State of Mississippi was below 50%, and so far, no significant compliance improvements have been reported. Wetlands assimilation is one of the Best Available Technology (BAT), allowed by the EPA. However, the State of Mississippi has not adopted the wetlands assimilation as a policy tool. On the contrary, the State of Louisiana has adopted policy guidelines of using natural wetlands to assimilate nutrients in secondarily treated municipal effluent, thus utilizing ecosystem services of natural wetlands, and improving the EPA regulation with reduced financial burdens to local communities. <br /><br /> We reviewed the state policy formulation process of wetlands assimilation in Louisiana by analyzing the implementation of the Clean Water Act from an inter-governmental relation among federal, state, and local governments for expansion of wetlands assimilation, and we found that the communities which have adopted the wetlands assimilation method have complied their NPDES permits successfully, with reduced financial burdens. <br /><br /> Local communities in Mississippi have been under serious financial burdens, resulting from declining residential population, and declining property tax base. In addition, increasing regulations and unfunded mandates, compounded with political pressures of no-property tax increase have been declining local government's capacity to comply with the environmental regulations. <br /><br /> State of Mississippi may need more active and trustworthy dialogues among State and local governments, scientists, and local community leaders, with results from science-based field studies, and the case studies available from neighboring states. We believe that the wetlands assimilation method is a strong alternative for cost-effective ways in increasing the NPDES compliance in Mississippi.<br /><br /><a href="/conference/pdf/jaeyoung_ko2016.pdf">Download presentation</a>
Enhancing ditch denitrification with rice cutgrass: experimental evidence for a simple nitrate runoff mitigation tool
Year: Authors: Taylor J.M., Speir S.L., Moore M.T., Scott J.T.
Widespread implementation of best management practices (BMPs) that mitigate nitrogen (N) runoff are needed to reduce significant environmental impacts including eutrophication of fresh and coastal waters. Denitrification is a biologically-mediated mechanism that converts NO<sub>3-</sub>N to N<sub>2</sub> gas and reduces N transport to downstream waterbodies. We investigated NO<sub>3-</sub>N mitigation and denitrification potential in ditch sediments vegetated with rice cutgrass (<em>Leersia oryzoides</em>). An initial study was conducted to quantify differences in N retention and denitrification during experimental runoff events between three different vegetation treatments: unvegetated, rice cutgrass, and common cattail (<em>Typha latifolia L.</em>). Vegetated mesocosms removed significantly more NO<sub>3-</sub>N from the water column than unvegetated systems. However, sediments planted with cutgrass had significantly higher average denitrification rates (5.93 mg m<sup>-2</sup> h<sup>-1</sup>) than cattails and unvegetated sediments (0.2 mg and 0.19 m<sup>-2</sup> h<sup>-1</sup>). Whole mesocosm mass balance indicated that denitrification accounted for as much as 56% of the immobilized nitrate over a 48 hr period. A follow up study examined the effects of nitrate availability on uptake and denitrification in sediments planted with cutgrass over four seasons. Michaelis-Menten models described the relationship between nitrate concentration and N<sub>2</sub> flux rates for spring, summer, and fall seasons. Summer denitrification models exhibited the highest V<sub>max</sub> and K, with maximum N<sub>2</sub> fluxes of approximately 20 mg m<sup>-2</sup> h<sup>-1</sup>. Denitrification rates were strongly correlated with NO<sub>3-</sub>N uptake by vegetated sediments in spring and summer, but low uptake in fall and winter resulted in virtually no net denitrification during these seasons. Whole mesocosm 48 hr denitrification was estimated using models from study 2 applied to data from study 1. The predicted contribution of denitrification to N mitigation based on Michaelis-Menten kinetics was slightly higher, less variable, but within one standard error of original estimates based on applying average denitrification rates to mass balance estimates for the same data set (310.80 ± 5.03 vs 284.48 ± 29.69 mg). Our results indicate that ditch sediments vegetated with cutgrass not only immobilize a significant fraction of nitrate, but also permanently remove significant amounts of immobilized nitrate through microbial denitrification. Ditches vegetated with cutgrass can provide an important tool for mitigating N runoff from agricultural landscapes, particularly during the growing season when ditches receive irrigation tailwater.
Calibration and comparison of forest canopy interception models
Year: Authors: Linhoss A., Siegert C., Levia D.F.
Rainfall interception by the forest canopy plays an important role in the water budget by removing water from the terrestrial hydrologic cycle. Effective models of canopy interception are critical for simulating the water budget and river flows. Over the years, several models have been developed to simulate canopy interception. Few comparative studies have been conducted that assess how well these models simulate measured interception. The objective of this study was to compare five mechanistic canopy interception models including the Rutter, Rutter Sparse, Gash, Sparse Gash, and Liu models. Each model was calibrated independently using PEST, and automatic parameter estimation routine. The five models were calibrated for American beech and yellow-poplar stands as well as under leafed and unleafed conditions. Overall, the models behaved somewhat similarly. Cumulative error ranged between 0.0% and 14.9%. The models were also assessed for their ability to accurately simulate interception during individual rainfall events. The coefficient of determination (R<sup>2</sup>) between measured and modeled interception events ranged between 0.21 and 0.48. An important reason for the low R<sup>2</sup> values is the fact that the models were unable to simulate very low or very high levels of interception. Measured interception ranged between 0.2 and 12.2 mm while modeled interception only ranged between 1.2 and 6.9 mm. These results indicate an important gap in our ability to simulate a substantial portion of the water budget.<br /><br /><a href="/conference/pdf/anna_linhoss2016.pdf">Download presentation</a>
Numerical Simulations of Spilled Coal-Ash in The Dan River and The Environment Impact of the Incident
Year: Authors: Jia Y., Altinakar M., Chao X., Zhang Y.
39,000 ton of coal ash and 27 million gallons of waste water were released accidentally into the Dan River from the Dan River Steam Station on 2/2/2014. The chemicals brought with the coal-ash and the waste water into the Dan River caused serious concerns of the residents along the river and government agencies because the river is an important source of water supply. Studies supported by the Duke Energy using a 2D numerical model, CCHE2D, were carried out. This is a general free surface flow model with sediment transport, pollutant transport and bed change simulation capabilities. The Dan River from the spill site to the downstream School Field Reservoir, a 40km curved channel stretch was simulated. The channel morphologic change due to sediment transport and coal ash transport were simulated for allocating the coal ash deposition in the alluvial system. Both bed load sediment and suspended sediment transport were both simulated. The coal ash is of very fine particles, most of them are treated as suspended sediments. Transport of Arsenic and Selenium brought by the incident are simulated to evaluate the environment impact. The simulation results are comparable to the data measured in emergency.
Multi-species environmental DNA screen of aquatic species in the Sipsey River in Alabama
Year: Authors: Mangum C., Homyack J., Atkinson C.
The Southeastern U.S. is rich in biodiversity with over 1000 species of fish, mussels and crayfish alone Aquatic species are often cryptic, found in low densities, and their current geographic distribution not well-described. Environmental DNA (eDNA) is an emerging technique to detect and identify species-specific DNA fragments in water and soil samples. Modern genome sequencing technology can obtain millions of DNA sequences from a single sample, making it possible to identify organisms by the residual DNA (e.g., feces, urine, skin cells) they shed in their environment. A pilot project was conducted to use data and samples from a freshwater mussel study for eDNA analysis, to evaluate both the effectiveness of the technology to identify known species and to refine field methods. Dr. Carla Atkinson, University of Alabama, is conducting a field study examining abundance and diversity of freshwater mussels in the Sipsey River, Alabama. The Sipsey River is one of the last free flowing rivers in Alabama and it is considered one of "Alabama's Ten Natural Wonders." The river has a 37 mussel species and 102 fish species reported and represents one of the best remaining and most intact mussel communities left in the United States. Water samples were collected in the vicinity of identified mussel species, and submitted for eDNA analysis. An overview of the mussel study and year one data collection will be presented, as well as eDNA field methodology. This non-invasive screening tool has many uses ranging from verifying presence or absence of threatened and endangered species to monitoring of invasive species. Collecting information on aquatic species is difficult and labor intensive with federal permits need for threatened and endanger species. This method is fast, cost effective, and does not require a permit.<br /><br /><a href="/conference/pdf/clay_mangum2016.pdf">Download presentation</a>
Drawdown II: Water quality and ecological responses to a managed hydrologic drawdown during autumn
Year: Authors: Lizotte R.E., Jenkins M.B.
A water drawdown of Roundaway Lake, a tributary of the Big Sunflower River, was initiated in mid-autumn to alleviate critical low river flow. While water releases have been demonstrated to alleviate critical low flows, effects of these releases on water quality in contributing tributaries is necessary to improve water resource management decisions. The purpose of the present study was to assess the responses of lake surface water chemical and ecological components including nutrients, phytoplankton and ecoenzyme activities. Lake drawdown began on October 17, 2016 and finished after 14 days when outflow was <0.1% of peak flows and shallowest depths occurred 35 days after drawdown with decreased depths of 56%, 23% and 90% at upstream, lake, and downstream sites, respectively, relative to pre-drawdown depths. Control pond depths during the study period ranged from 82-113% relative to pre-drawdown depths with changes due to evaporation and rainfall. Water samples were collected on days -3, 0, 1, 2, 3, 7, 14, 21, 28, 35, and 42 at the three drawdown sites and an adjacent control pond site (no drawdown) to account for natural seasonal variations. Chemical analyses included soluble nutrients (PO<sub>4-</sub>P, NH<sub>4-</sub>N, NO<sub>2-</sub>N, NO<sub>3-</sub>N), total nutrients (TP, TN) and organic carbon. Ecological analyses included algal chlorophyll, phycocyanin and photosynthetic efficiency as well as a suite of five ecoenzyme activities. Nutrient changes were greatest at sites with the largest changes in water depth. Upstream dissolved organic nitrogen (NH<sub>4-</sub>N, NO<sub>2-</sub>N, NO<sub>3-</sub>N) increased by >100%, while organic carbon exhibited bimodal changes. Downstream PO<sub>4-</sub>P, C:N ratios, and C:P ratios all increased by >100%, organic carbon increased by 50% and TP decreased by 45%. Lake nutrients exhibited modest bimodal changes in NH<sub>4-</sub>N, NO<sub>2-</sub>N and organic carbon while control pond NO<sub>2-</sub>N decreased by 50%. Similar to nutrients, algal responses were strongest upstream and downstream. Upstream phycocyanin concentrations increased by >70% while photosynthetic efficiency decreased by 75-80%. Downstream chlorophyll and phycocyanin concentrations decreased by 75-85% and photosynthetic efficiency decreased by 66-90%. Lake and control algal responses were modest with chlorophyll concentrations decreasing by 22-30% and photosynthetic efficiency decreasing by 25-45%. Ecoenzyme activity responses were modest at most sites with bimodal changes to Β-glucosidase:alkaline phosphatase ratios upstream and leucine aminopeptidase in the lake. Greatest changes occurred downstream where Β-N-acetylglucosaminidase, fluorescein diacetate and alkaline phosphatase decreased by 76%, 77% and 98%, respectively. The study contributes valuable information supporting water resource management goals to sustain river and lake ecosystem integrity.
Surface-Geophysical Surveys to Characterize Lithological Controls on Aquifer Recharge and Surface Water-Groundwater Exchange
Year: Authors: Miller B.V., Kress W.H., Ladd D.
The U.S. Geological Survey (USGS) developed a groundwater-flow model of the Mississippi Embayment Regional Aquifer System (MERAS) that incorporated multiple aquifers including the Mississippi River Valley alluvial (MRVA) aquifer. In addition to groundwater withdrawal, two major fluxes in the model are recharge from precipitation and surface water-groundwater exchange. In order to determine appropriate values for recharge to the MERAS model, the USGS has utilized two published datasets- the geomorphology of Quaternary deposits and local soil surveys. At a regional scale, recharge in the MERAS model correlate well with large-scale geomorphological features. However, there is little spatial variability, so local-scale variations in recharge are not adequately represented. Higher resolution data such as soil coverages provide a more spatially-variable estimates of recharge, but, soil-survey data often characterize the shallow soil horizon and do not reflect the generalized geomorphological features in which the horizon lies. In addition, streambed sediments may differ greatly from the mapped geomorphologic areas and shallow soils due to alteration from stream mechanics. Thus, geomorphologic maps and soil information are both types of surficial information that may not accurately reflect the underlying hydrogeology that controls infiltration of recharge water or the composition of streambed sediments. <br /><br /> In 2016, the USGS conducted a surface-geophysical survey to characterize the near-surface (<15 m) lithology that controls recharge to the MRVA aquifer and surface water-groundwater exchange at selected locations in northwestern Mississippi. Two-dimensional vertical profiles of resistivity identified differences in geoelectrical properties of the streambed for reaches of the Tallahatchie (60 km), Quiver (50 km), and Sunflower (70 km) Rivers. Resistivity profiles of each stream were able to detect boundaries of individual geomorphic features. In addition, terrestrial-based resistivity surveys identified variations in geoelectrical properties from Money to Steiner, Mississippi, a distance of approximately 68 km. The terrestrial-resistivity survey showed distinct differences in surface soil resistivity based on lithology. Drilling logs of wells along the Sunflower River confirmed that lithologic descriptions correlated positively with the resistivity profiles.
Characterizing groundwater and surface-water interaction throughout the Mississippi Delta using hydrograph-separation techniques combined with near-st
Year: Authors: Killian C., Barlow J., Barlow P., Kress W.H., Schmitz D.
The Delta, an area dense in agriculture, is situated between the Mississippi and Yazoo Rivers in northwest Mississippi. Stream and groundwater levels in the Delta have shown declines with the increase in irrigation to support agricultural production. In 2016, the U.S. Geological Survey (USGS) began a study to better understand the effects of pumping on groundwater and its availability in the Mississippi River Valley alluvial (MRVA) aquifer. The alluvial aquifer is the uppermost hydrologic unit in the Delta and supplies most of the groundwater used for agricultural irrigation. Understanding the relation between withdrawals and groundwater response in the alluvial aquifer could allow for the estimation of changes in groundwater availability over time and can help to determine the best water-resource-management practices for the study area. A spatially-distributed network of paired groundwater and surface-water streamgage sites provided hydrologic data to characterize groundwater/surface-water interaction throughout the Delta. Baseflow, the amount of groundwater that contributes to streamflow, was estimated for each site using hydrograph-separation methods. The USGS Groundwater Toolbox open-source software provides several techniques for hydrograph separation and was used for this study. Recently collected geophysical data along selected streams in the Delta provided insight to the hydraulic conductivity, or ease with which water moves through the soils and unconsolidated sediments, was coupled with the hydrograph-separation results. This combination of techniques allowed for better characterization of groundwater/surface-water interaction at the selected sites. Characterizing and defining these types of hydrologic relations will help USGS scientists refine a regional model of the Delta that will be used to aid water-resource managers in future decisions pertaining to the alluvial aquifer.
Estimating water budget components of evapotranspiration, recharge, and runoff for Mississippi and the Mississippi Alluvial Plain
Year: Authors: Reitz M., Sandord W.E., Senay G.B., Kress W.H.
As water resources become increasingly strained in the US and globally, the development of reliable water availability estimates is needed for making informed water use management decisions. Here we present new 800m annual estimates of water budget components of evapotranspiration (ET), surface runoff, and recharge, produced using various data sources such as soil properties, surficial geology type, stream gage and climate data for 2000-2013. Groundwater-sourced irrigation is included as a component in the local water budget, using data from USGS county-level compilations. The ET and recharge estimates compared favorably when checked against independent field data, and against other ET estimation methods. We show results for the state of Mississippi, and also for the focus area of the Mississippi Alluvial Plain, which has seen significant impacts on water resources due to irrigation and groundwater pumping. Comparisons with USGS groundwater withdrawal data indicate regions where rates of water use may be unsustainable. We summarize results of the water budget estimates for the 2000-2013 timespan for both the state of Mississippi and the Mississippi Alluvial Plain. Finally, we show preliminary results of current work to estimate water budgets on a monthly timescale, through a combination of remote sensing and ground-based data.
Quantifying Recharge to the Mississippi River Valley Alluvial Aquifer from Oxbow-Lake-Wetland Systems
Year: Authors: Gratzer M., Davidson G., O'Reilly A., Rigby J.R.
Irrigation-related groundwater withdrawals have caused declining water levels in the Mississippi River Valley Alluvial Aquifer (MRVAA) since the late 1920s. To manage this resource, recharge sources must be quantified. This study examines recharge through oxbow lakes, which are numerous in the Mississippi Delta. Previous investigations at Sky Lake, an ancient Mississippi River oxbow with an associated wetland, near Belzoni, Mississippi, suggest that oxbow wetlands may contribute significant recharge to the MRVAA. Multiple methods using geologic, hydrologic, and temperature data are being employed to identify and quantify recharge from the Sky Lake oxbow lake-wetland system. Two wetland soil cores were collected to depths of approximately 7 m, encountering 6 m of clay and silt before penetrating into sands and gravels. Monitoring of MRVAA water levels in two piezometers in the wetland and nine monitoring wells in Sky Lake's vicinity began during the 2016 drought and will continue through the rainy season to track groundwater responses. The potentiometric surface will be mapped to identify possible groundwater mounding beneath the lake, which would indicate vertical recharge. Preliminary results from mid-December, 2016, indicate a general groundwater flow direction to the west beneath the lake. Wells are outfitted with temperature-recording data loggers at specific depth intervals. The groundwater temperature profiles have the potential to differentiate localized wetland-recharge from regionally distributed infiltration, or from recharge from the nearby Yazoo River. Soil temperatures 30 and 60 cm below ground at ten points in the wetland are also being monitored over time to characterize small-scale variations in downward flux. Preliminary results are consistent with earlier work indicating preferential flow pathways through the fine-grained bottom sediments due to an abundance of buried trees and limbs in various stages of decomposition.
A century of precipitation trends in the Mississippi Delta region and implications for agroecosystem management
Year: Authors: Yaserer L.M., Bingner R., Locke M.
With nutrient-rich soils and a humid climate, the Mississippi Alluvial Plain (i.e. the Delta) within the Lower Mississippi River valley is a productive region for agriculture and a critical contributor to the national agricultural economy. Irrigation plays a large role in the fecundity of this region; however, precipitation patterns also have a significant impact on yield, crop choice, management practices, and ambient water quality. In this study precipitation trends in the Delta for over 100 years are explored. The average annual rainfall from 1901 to 2000 in the Delta was approximately 52 inches. However, precipitation has increased an average of 0.5 inches per decade in the region. Using the NOAA nClimDiv dataset and the network of USDA-NRCS SCAN weather stations, regional precipitation trends for the entire Delta and location-specific patterns are analyzed. Projected precipitation estimates from the CMIP5 dataset (provided by the World Climate Research Program's Working Group on Coupled Modeling) are used to provide insight on future precipitation patterns and implications for agroecosystem management planning within the Delta.
Water consumption and yield variability of nonirrigated and irrigated soybeans in Mississippi dominant soils across years
Year: Authors: Feng G., Ouyang Y., Reginelli D., Jenkins J.
Soybean is the most important crop in Mississippi in both acreage and value. In 2015, the Mississippi soybean harvested area was 2.27 million acres and a total value of $1.04 billion, surpasses other major crops combined. Approximately one-half of Mississippi soybeans are grown under rainfed conditions and another half are irrigated. In order to stabilize dryland soybean yield and improve yield by irrigation, it is essential to determine yield, water requirement and consumption of both non-irrigated and irrigated soybeans in Mississippi dominant soils under different climate conditions over years.<br /><br /> Field experiments were conducted in Noxubee county for those objectives on Vaiden clay, Okolona silty clay, and Demopolis clay loam at a private Good Farm in 2014 and on the Brooksville silty clay at Mississippi State University Black Belt Branch experiment station in 2015 and 2016. <br /><br /> During the entire soybean growing season from 1895 to 2014, the average long-term reference evapotranspiration and crop water requirement (ETc) were 720 and 542 mm, mean rainfall was 432 mm, rainfall of wet, normal and dry category years was 597, 421 and 280 mm. <br /><br /> During soybean season in 2014, 2015 and 2016, rainfall were 365, 388 and 284 mm, soybean water requirement were 428, 455, and 504 mm. In 2014, 2015 and 2016, rainfed soybeans consumed 402, 417, and 347 mm water and produced 5672, 2736, and 1806 kg ha<sup>-1</sup> grain, in contrast, irrigated soybean consumed 440, 526, and 478 mm water and yielded 6264, 3109, and 3031 kg ha<sup>-1</sup> grain. <br /><br /> The APEX (Agricultural Policy/Environmental eXtender) model was applied on nine soil types (Vaiden clay, Catalpa, Okolona, Griffith, Sumter, Kipling and Brooksville silty clay, Demopolis clay loam, and Leeper sandy loam) in Eastern Central Mississippi from 2002 to 2014. <br /><br /> APEX simulated grain yield of rainfed soybean ranged broadly from 2.24 to 6.14 Mg ha<sup>-1</sup> on nine soil types over the 13 years. The average yield in wet, normal and dry years was 4.88, 4.51 and 3.74 Mg ha<sup>-1</sup>, respectively. Simulated yield potential without water stress due to irrigation varied from 4.47 to 6.51 Mg ha<sup>-1</sup>. Compared with rainfed soybean, the average increase in yield by irrigation ranged from 0.34 to 1.60 Mg ha<sup>-1</sup> among the nine soils. Griffith, Sumter and Demopolis had the highest average yield gap (difference between yield potential and the rainfed yield), ranged from 1.37 to 1.60 Mg ha<sup>-1</sup>. Average irrigation amount required to achieve potential yield ranged from 16 to 377 mm across the nine soil types. High variability of water consumption as well as grain yield was observed for both nonirrigated and irrigated soybeans on different soils and on a given soil over different years. Therefore, it is necessary to explore production/management options for different soils that will increase opportunities for consistent yields and profits across years without irrigation.<br /><br /><a href="/conference/pdf/gary_feng2016.pdf">Download presentation</a>
Quantifying crop water requirements in the MS Delta using eddy covariance and energy balance methods
Year: Authors: Anapalli S.S., Fisher D.K., Reddy K.N., Ruixiu S.
With competing demands for fresh water from human, urban, and industrial sectors, water available for irrigated agriculture is rapidly declining; this calls for a more judicious use of the limited share of water available for crop irrigations. Accurately quantifying crop water requirements and providing crops with the right amount of water at the right time to optimize crop water productivity holds the key to addressing this challenge. While large field lysimeters allow us to grow crops for quantifying ET directly from the crop-field, they are expensive and time-consuming to install successfully and maintain for long-term data collection for analyzing climate variability impacts on crop water requirements. Eddy covariance (EC) and energy balance (EB) methods are easier to install in crop fields and are portable, and provide two scientifically sound methods for indirect, accurate measurements of water requirements (ET; evapotranspiration) of cropping systems. Nonetheless, the EC method has been widely known to have energy balance closure problems — imbalance in matching energy inputs to the outputs. In the evolving scenario, we embarked on a research program for monitoring ET from corn and soybean crops using both EC and EB approaches, for comparison with each other and accounting for energy balance non-closure artifacts on the EC data generated. In the EB method for quantifying ET, a surface energy balance equation is applied to a soil-plant surface using ground-based and remote-sensing measurements of the system variables, and ET (expressed as latent heat flux) is estimated as the residual term of the energy balance equation when other fluxes in the equation are either measured or calculated. The EC system consists of an omnidirectional sonic anemometer and an open-path infrared gas analyzer with data recorded at a frequency of 10 Hz on a data logger and analyzed with Smartflux software (LiCor, Lincoln, NE, USA). In this project, crops were grown in 40-ha fields planted to soybean and equipped with the EC and EB systems in 2016. In general, computed daily values of ET from EB and EC methods deviated from the computed short grass (ET<sub>o</sub>) and alfalfa (ET<sub>r</sub>) reference crop ET. However, total seasonal ET from both EB and EC methods were comparable with ET<sub>r</sub> and ET<sub>o</sub>. The EC and EB methods tested show high potential for quantifying crop ET in cropping systems in the MS Delta region.
Weather map classification as a tool for the hydroclimatological community
Year: Authors: Siegert C.M.
Weather map classification, also known as synoptic classification, is a tool used to simplify diverse atmospheric variables into a single weather type, which allows researchers to relate large-scale atmospheric circulation to regional- and small-scale surface environments. Synoptic classification has many applications for understanding the response of the surface environment to atmospheric forcings as evidenced in the range of atmospheric pollutant studies. However, full applicability has been under-utilized to date, especially in disciplines such as hydroclimatology, which are intimately linked to atmospheric inputs. Using a combination of principal components analysis and cluster analysis, a daily synoptic calendar can be developed from readily available atmospheric measurements including temperature, sea level pressure, wind, and cloud cover. These methods are not site specific and may serve as guidance for researchers who wish to employ synoptic classification techniques in their own region of interest. <br /><br /> Case studies are presented to demonstrate the utility of synoptic techniques in hydroclimatological applications including precipitation characteristics, soil moisture, and stream discharge. These examples illustrate how synoptic typing can be used (1) to quantify direct relationships between atmospheric patterns and precipitation characteristics or (2) to quantify relationships further removed in the hydrologic cycle such as atmospheric patterns and stream discharge. The cascade of processes in the hydrologic cycle are complex and considerable effort has been made to understand, model, and predict these relationships. As such, synoptic classification may be applied to a broad array of hydrological research questions and warrants further consideration by the hydroclimatological community.
Variable Rate Irrigation Technology for Improving Water Use Efficiency
Year: Authors: Sui R.
VRI technologies allow the producers to site-specifically apply irrigation water at variable rates within the field to adjust the temporal and spatial variability in soil and plant characteristics. Adoption of VRI has the potential to improve water use efficiency. VRI technologies are normally implemented on self-propelled center-pivot and linear-move sprinkler irrigation systems. VRI practices require specialized hardware and software. The hardware requirements include a GPS receiver to determine the spatial position of the irrigation system and an intelligent electronic device to control individual sprinklers or groups of sprinklers to deliver the desired amount irrigation water on each specific location within the field according to the VRI prescription. The software required includes the algorithms to calculate the water application rates and the computer programs to create VRI prescription maps. This proposed presentation will introduce the VRI technology and provide a case study on VRI application in Mississippi Delta for improving water use efficiency.
Rice irrigation strategies: Alternate wetting and drying and methane reductions
Year: Authors: Runkle R.K., Suvocarev K., Reba M.
Approximately 11% of the global 308 Tg CH<sub>4</sub> anthropogenic emissions are currently attributed to rice cultivation. In this study, the impact of water conservation practices on rice field CH<sub>4</sub> emissions was evaluated in Arkansas, the leading state in US rice cultivation. While conserving water, the Alternate Wetting and Drying (AWD) irrigation practice can also reduce CH4 emissions through the deliberate, periodic introduction of aerobic conditions. Seasonal CH<sub>4</sub> emissions from a pair of adjacent, production-sized rice fields treated with continuous flood (CF) and AWD irrigation were estimated and compared during the 2015 and 2016 growing seasons using the eddy covariance (EC) method on each field. The seasonal cumulative carbon losses by CH<sub>4</sub> emission significantly less for the AWD treatment. The substantial decrease in CH<sub>4</sub> emissions by AWD supports previous chamber-based research and offers strong evidence for the efficacy of AWD in reducing CH<sub>4</sub> emissions in Arkansas rice production. Plans for the 2017 measurement season will be discussed, including a mixture of EC and surface renewal micrometeorological techniques on 16 adjacent 40-acre fields under various irrigation practices in northeast Arkansas. The AWD practice is incentivized by several USDA-NRCS conservation programs and is used for carbon offsets trading, so reductions of both water use and CH<sub>4</sub> emissions are encouraged on a regional scale.
Variable pathways and geochemical history of seepage under the Mississippi River Levee: Observations from the 2011, 2015, and 2016 floods
Year: Authors: Voll K., Davidson G., Kelley J., Corcoran M., Borrok D., Ma L.
Seepage beneath levees during flood stage becomes a concern when piping occurs, opening up channels beneath the levee and forming sand boils where transported sediments discharge. Along the lower Mississippi River, the pathway beneath the levee varies with surface geology, following deeper paths where the levee sits on channel fill deposits, and shallower paths where it sits on sand bar deposits. A preliminary investigation north of Vicksburg, MS, during the 2011 flood, demonstrated the potential for using aqueous geochemistry to differentiate sand boils forming at the end of deep and shallow flow pathways. Deeper flow through the geochemically stratified Mississippi River Valley Alluvial Aquifer (MRVAA) produces discharge low in oxygen and high in redox sensitive elements such as iron and arsenic. Shallow flow contains measureable oxygen and much lower iron and arsenic concentrations. Sampling during the 2015 and 2016 events for bulk chemistry, trace metals, tritium, and stable isotopes of oxygen, hydrogen, iron, and strontium, is enhancing our understanding of the nature of flow and the geochemical evolution of the local groundwater. <br /><br /> Oxygen and hydrogen isotopes suggest that river water experiences significant evaporation before recharging to the MRVAA. Shallow flow pathways beneath the levee are characterized by lower iron isotope ratios, and higher strontium isotope ratios, reflecting interaction with unique mineral phases and distinct reaction pathways. Sand boil discharge following deeper flow pathways group isotopically and geochemically with relief wells, or between relief-well and river end-members. Boil discharge following shallow pathways does not just plot closer to river water. River water passing through the shallow aquifer is altered in ways that will require installation and sampling of dedicated shallow wells to fully understand. Tritium results reveal a dynamic system, where flow paths may vary over between floods or within a continuous flooding event.<br /><br /><a href="/conference/pdf/kaitlin_voll2017.pdf">Download presentation</a>
Enhanced Characterization of the Mississippi River Valley Alluvial Aquifer Using Surface-Geophysical Methods - a Pilot Study near Money, Mississippi
Year: Authors: Adams R.F., Kress W.H., Minsley B., Kass M.A.
The Mississippi River Valley alluvial (MRVA) aquifer is a complex and poorly understood near-surface aquifer system used to supply irrigation for agriculture across the alluvial plain of the Lower Mississippi River basin. The thickness and extent of the aquifer units are typically determined by evaluating geophysical and driller logs from test holes at spatially discrete points. Surface-geophysical data, along with borehole-geophysical and lithologic data from test holes, can be used to provide high-resolution three-dimensional characterization of the aquifer system. In 2016, the U.S. Geological Survey (USGS) conducted a pilot study to demonstrate the use of surface-geophysical methods for delineation of near-surface geologic features, characterization of alluvial aquifer properties, and evaluation of surface water/groundwater exchange in the MRVA. The area chosen for this pilot was a 100-acre plot in Money, Mississippi. The study approach integrated waterborne and terrestrial resistivity and nuclear magnetic resonance (NMR) surveys to develop a three-dimensional geoelectrical model of the site. This integrated approach helped define the 100-150 feet of sand aquifer and the contact of the clay-confining unit beneath it. Shallow terrestrial-resistivity surveys confirmed that the clay-rich loam at the land surface continues as a clay-rich alluvial deposit approximately 25-50 ft thick beneath the study area. The presence of this relatively impermeable layer above the alluvial aquifer has the potential to limit vertical recharge from precipitation or irrigation. The NMR survey was used to determine that the aquifer volume consists of 30% water with two-thirds of that available for use. Comparisons of the waterborne- and terrestrial-resistivity surveys were used to identify that a hydraulic connection or potential for water exchange, between the Tallahatchie River and the MRVA is possible. These geophysical observations provide a more accurate understanding of the local hydraulic properties and hydrology of the MRVA aquifer at this site, and will contribute new data to constrain a regional, numerical groundwater model.<br /><br /><a href="/conference/pdf/ryan_adams2017.pdf">Download presentation</a>
Groundwater dynamic modeling and sustainable management in Big Sunflower River Watershed
Year: Authors: Han M., Feng G., Ouyang Y., Gao F.
Groundwater resource in Mississippi Delta is under a serious threat due to overdraft by agricultural pumpage, and showing a decreasing trend since 1970s. Groundwater management strategies are needed for the sustainable development of agriculture in Delta. This study analyzed groundwater dynamics in Big Sunflower River Watershed (BSRW) from 2000 to 2009 using MODFLOW model. The MODFLOW model was set up to quantify the changes in groundwater storage, level, and balance during this simulation period. The model was first calibrated with measured data and compared with the results from previous modeling studies in BSRW with a good agreement. Two scenarios were then chosen to evaluate groundwater management: 1) different crop rotation/sequence, and 2) coupled use of surface water and groundwater for irrigation. The results revealed that the annual change in groundwater storage was highly correlated to the annual amount of precipitation in this region. As the annual precipitation was larger than 60 inch, the groundwater storage increased due to receiving more rainwater recharge and pumping less groundwater for irrigation. Coupling use of surface and ground waters is a sustainable way for water resources management in this region. Appropriate percentages of utilizing groundwater and surface waters were determined under current weather conditions and future climate change scenarios.
Grazing Cattle Preference for Automated Water Troughs and Shade Trees versus Pond Use for Drinking and Heat Stress Mitigation
Year: Authors: Parish J.A., Rutherford W.C., Best T.F., Stewart C.O.
British breed heifers aged 19 to 21 months and 4 to 6 months pregnant were grazed on a 25-acre pasture of Kentucky-31 toxic endophyte-infected tall fescue starting May 18, 2015 at the Prairie Research Unit in Prairie, MS. They were fitted with global positioning system collars that recorded position within the pasture at 5-minute intervals until July 28, 2015. Heifers had free-choice access to a surface pond, automated open-faced water trough supplied by well water, and shade trees. Heifers spent 73.9 ± 0.12% of time away from water and shade sources, 23.8 ± 0.12% of time in shade, 1.4 ± 0.03% of time at the water trough, and 1.0 ± 0.03% of time at or in the pond. Comparing time spent at drinking water sources directly, heifers were 1.4 times more likely to be at the water trough than the pond. In a direct comparison of shade use versus pond use for heat stress mitigation, heifers were 23.9 times more likely to be in the shade than the pond. Ambient temperature affected (P < 0.01) animal location within the pasture. Mean temperatures for the different location classifications were: shade (84.5°F), water trough (82.6°F), pond (81.8°F), and other (77.6°F). At greater ambient temperatures, heifers were more likely (P < 0.01) to be located under shade than at water sources or out grazing. Likewise, heifers were more likely (P < 0.01) to be grazing or otherwise away from shade and water sources at lesser ambient temperatures. These results suggest a strong preference by cattle for shade over pond use during late spring and summer as well as a preference for water trough use over pond use. Thus, by providing shade and an alternate drinking water source, pond use by cattle for drinking and heat stress mitigation purposes may be lessened.
Social Indicators: A Tool to Measure Change Among Hypoxia Stakeholders
Year: Authors: Guzman S., Cossman R.E., Ingram R.
Water quality problems that have accumulated over many decades similarily take decades to correct. This is the case when considering the complexity, scale, causes, and impacts of Gulf of Mexico hypoxia. Social dimension plays a key role because it is people who dictate interactions with the environment. Every individual (functionalized as "stakeholders"), community and culture has a set of beliefs and attitudes that guide decision-making and influence behavior. The success of nutrient reduction strategy implementation in state-designated priority watersheds depends upon a large percentage of watershed stakeholders understanding both the water quality impacts of their land use activities and the importance of conservation. Thus, an important social-environmental metric must include confirming that awareness and attitudes are changing, and behaviors are being adopted. Social indicators can inform planners and managers of modifications needed to their nutrient reduction strategies to increase their effectiveness. These social metrics such as input and feedback from stakeholders can supplement environmental metrics. In this poster we present the concept of social indicators as a viable metric for agricultural and water management. The ultimate goal is to increase the adoption of standardized social indicators as best practices for measuring watershed interventions.
Simulating cotton water use and yield under rainfed and full irrigation conditions using RZWQM2 model in the Lower Mississippi Delta Region
Year: Authors: Ma X., Feng G., Sui R., Jenkins J.
Sustainable agricultural water management requires knowledge of crop water use and productivity under both rainfed and Irrigation conditions. Our objective was to determine the yield and water use of both nonirrigated and fully irrigated cotton in the Lower Mississippi Delta Region. The CSM-CROPGRO-Cotton v4.6 model within the Root Zone Water Quality Model (RZWQM2) were applied. The model was calibrated and validated using measured data at Stoneville Experimental Station in 2015 and 2016 Results suggested that the calibrated model simulated cotton yield and water use had good agreement with measured data in field. Simulation study discovered that the lowest rainfed yield was less than 2500 kg ha<sup>-1</sup>, and the highest irrigated yield were more than 3600 kgha<sup>-1</sup>.
Dynamic mechanism and simulation of soil and water conservation practices in restraining runoff, sediment and nutrient losses on slopes
Year: Authors: Han Y., Feng G.
Rainfall is a major dynamic driving factor of soil erosion and nutrient loss on different slopes. Soil and water conservation practices can change the dynamic process of soil and water losses, it is an important measure to reduce erosion and nutrient loss. In this study, four types of soil and water conservation practices, i.e., fish-scale pits, narrow terrace, shrub cover and agricultural landuse, were tested from 2001 to 2010. The results showed that all of these practices for soil and water conservation can significantly reduce soil erosion and nutrient losses. Compared with other practices, fish-scale pits most effectively reduced runoff, sediment and nutrient losses (the total losses of runoff, sediments, TP and TN were 20%, 2%, 10% and 36%, respectively, from the bare land in the same area), followed by 30% shrub coverage, narrow terrace and agricultural landuse. These soil and water conservation practices decreased shear stress, stream power, cross-section specific energy and soil detachment rate as well as reduced surface disturbances and soil erosion. The mechanisms of restraining soil and water loss by those conservation practices were quite different. In this study, rain intensity and erosion dynamic parameters (flow rate, Reynolds number, Froude numbers, Darcy resistance coefficient, Manning coefficient, shear stress, stream power, unit runoff power and cross-section specific energy) were considered as major factors in the empirical models for estimation of runoff, sediments, TP and TN at different runoff experiment sites. Statistical models were developed through stepwise linear regression analysis, correlation coefficient R of the models ranged from 0.65 to 0.99, indicating that simulated results were in good agreement with measured values.
Integrating hydrogeology, well design and drilling techniques to maximize production and minimize problems
Year: Authors: Collier H.
Constructing a water well that maximizes its production rate, efficiency, and lifespan requires integrating hydrogeology, well design, and drilling techniques. Unfortunately, this is not always the case. When engineering a well, it is critical that both the initial and final design be based on site specific geology. The initial well design should be based on a hydrogeologic study, with pilot or test hole data (e.g. geologic description of drill cuttings, sieve analyses, borehole geophysical logs, water analyses) used to finalize the well design.<br /><br /> Well specifications are a second critical component for successful well construction. They serve three functions: protect the client, assist the drilling contractor, and ensure a quality well. This talk will discuss items that should be included in well specs (e.g. drilling fluid properties, testing procedures, guarantees), along with case histories of what happens when they are deficient. <br /><br /> Daily, onsite monitoring throughout drilling and well construction is a third critical component. It serves the same three functions: protect the client, assist the drilling contractor, and ensure a quality well. A high capacity water well is a significant financial investment warranting professional, third party monitoring. Partnering with the drilling contractor minimizes problems and helps insure the success of the project. Case studies vouch for the wisdom of this approach. <br /><br /> An orchestration of hydrogeology, engineering design, and construction oversight is imperative to deliver to the client a well project that ensures quality construction and maximizes production and infrastructure lifespan.
Interplay of water quality and vegetation in restored wetland plant assemblages from an agricultural landscape
Year: Authors: Shoemaker C.M., Ervin G.N., DiOrio E.W.
Water quality degradation from excessive fertilizer use and runoff is a worldwide problem. While this degradation impacts wetlands, these systems can also be a vehicle for water quality improvement. Restoration of wetlands in agricultural landscapes has recently increased, but little work has evaluated the relationship of plant assemblages and water quality parameters in restored, non-treatment wetlands. This study examines the impact of self-designed wetland plant assemblages on nitrogen and sediment dynamics. Thirty mesocosms were seeded with soil from restored wetlands and allowed to develop from the seed bank to emergent assemblages. During the 2015 growing season (seven to nine months after establishment), these assemblages were exposed to treatment loads of nitrogen and sediment, common stressors to wetlands in agricultural landscapes. Water samples were taken up to five days post-treatment in July and September to quantify interactions between the stressors and plant assemblages. Analyses showed plant assemblage identify was not structured by treatment, but by the site of soil origin. Treatment removal rates were influenced by total amount of the stressor present, with nitrogen removal rates being higher, in relative terms, in low nitrogen amended treatments. Additionally, plant quality, not quantity, was linked to nitrogen and sediment loss rates, and over time, elevated nitrogen and sediment loads were associated with decreased plant assemblage quality. This study demonstrates the ability of plants from restored wetlands to affect nutrient and sediment dynamics, with three significantly differing plant assemblages all exhibiting substantial nutrient and sediment reduction capacity. Nevertheless, we also found that in a relatively short time (seven to nine months) common stressors in agricultural settings can significantly impact wetland plant assemblage quality, and that this may be linked to a reduced capacity for nutrient and sediment removal.
The Rainworks Challenge Bioretention Demonstration Project
Year: Authors: Gallo W.
Raingardens and bioretention facilities are being explored for their application in urban environments all across the United States. However, each location is unique, requiring specific soil, climate, rainfall, and even political responses. Over the past year, MSU faculty and students have designed and built a demonstration facility on MSU's Starkville campus that is designed to meet the specific requirements of an urban site in central Mississippi. <br /><br /> Funded by an EPA grant, the demonstration facility captures water from a campus building for reuse in a 2,000 gallon cistern and manages the remaining rainfall in an engineered bioretenation basin. The facility is designed to be seamlessly integrated into the surrounding site and offers educational kiosks that explain the various layers and design considerations that go into a bioretenation basin. The facility uses adapted and native species to reduce irrigation demands in summer. The plants thrive in eighteen inches of biorentention soil mix that filters pollutants and absorbs rainfall. Due to the heavy clay soils of central Mississippi, a gravel layer was installed below the soil to allow for storage over a longer period of time and move water out of the facility in larger events. <br /><br /> The project was designed and built through a collaborative process by students from Landscape Architecture, Graphic Design and Civil Engineering. At each step students were able to make real world decisions that impacted the final outcome of the demonstration facility. This process has helped to prepare them to be leaders in bioretention design after graduation and to influence the sustainable design of our cities.<br /><br /><a href="/conference/pdf/cory_gallo2017.pdf">Download presentation</a>
The Mississippi Water Security Institute: Report on Year 1; Plans for Year 2
Year: Authors: Ochs C.A., Young D.B., Sullivan-Gonzalez D.
Earth, Air, Fire, and Water. Ancient Greeks considered these the essentials to support life on earth - a wise observation. From Earth, nourishment is derived. From Air are provided the gases of respiration. From the Fire of our Sun we are bathed in the catalytic energy necessary for complex organization. But only where there is also Water can we "live long and prosper". In May 2016, we completed the first workshop of the Mississippi Water Security Institute (MS WSI). Our purpose was to introduce undergraduate honors students to the challenges and complexities of how we use and manage the state's water resources to meet present and future needs. The 2016 MS WSI involved 16 students from four Mississippi universities. The regional focus in our first year was on the Mississippi Delta, a place of great importance to the state's economy but also of striking contrasts; high agricultural production at the expense of enormous resource use; an historically wet wilderness with only remnants remaining outside the levees; islands of economic prosperity in a sea of rural poverty; where water seems inexhaustible but in fact can be consumed faster than it is replenished. Over our two-week Institute, we investigated the means by which we might use water in this vast region to jointly promote broad economic development, and human community health, while supporting ecosystem health. We were visited by numerous speakers representing different areas of expertise related to water use and management, from farming to law to conservation, and we made several field trips to sites of interest in the Mississippi Delta. In this talk, we will present outcomes of student learning from the 2016 workshop, and discuss plans for the upcoming 2017 MS WSI workshop on urban water systems in Mississippi.<br /><br /><a href="/conference/pdf/clifford_ochs2017.pdf">Download presentation</a>
Overview of Gulf of Mexico Hypoxia Policy in 2017
Year: Authors: Daigle D.
Doug Daigle, Coordinator of the Lower Mississippi River Sub-basin Committee, will give an overview of current policy to address the Gulf of Mexico hypoxic zone, focusing on the national Action Plan and Task Force that Mississippi and other lower river states are participants on. The revised Goal and Interim Target of the Action Plan will be explained, since they set the direction for joint action among Task Force states and agencies for the next decade, and provide the broader context for the work of SERA-46 and state and federal agencies described by other speakers in this session.<br /><br />Doug Daigle has coordinated the Lower Mississippi River Sub-basin Committee, part of the national Mississippi River/Gulf of Mexico Watershed Nutrient Task Force, since organizing it in 2003. The Sub-basin Committee consists of Arkansas, Louisiana, Mississippi, Missouri, and Tennessee, along with federal partner agencies, researchers, and stakeholders in the region. He also coordinates the Louisiana Hypoxia Working Group, a monthly forum held at Louisiana State University.<br /><br /><a href="/conference/pdf/daigle_doug2016.pdf">Download presentation</a>
Social Indicators: a New Metric to Guide, Measure, and Accelerate Implementation of State-Level Nutrient Reduction Strategies
Year: Authors: Guzman S.M., Cossman R.E., Ingram R.
Major barriers in water conservation are the development of effective strategies to improve the quality of freshwaters, and management of the current nutrient loads released by agricultural production. Decision makers require a set of technical, environmental, landscape, and social measurements to restore the quality of their watersheds. Social metrics contribute to the understanding of how individuals and communities perceive, and incorporate, nutrient management plans in their agricultural processes. They are also short term metrics in which change (i.e., delta) can be quantified quickly. Individual producers and users have a set of beliefs and attitudes that make them respond differently to a specific situation. In this project we refine social indicator metrics for agricultural and water management with an emphasis on nutrient reduction, promote an expansion of the existing Social Indicators Planning & Evaluation Systems/Social Indicators Data Management & Analysis Tool (SIPES/SIDMA) throughout the Mississippi Atchafalaya River Basin, and lay the groundwork for an active social indicators users community among policy researchers and regulatory agencies. The overall goals of this project include 1) identifying social science experts and potential users of social indicators in the existing Hypoxia Task Force (HTF) states to build the foundation for establishing a community of practice at the state-wide and Mississippi/Atchafalaya River Basin (MARB)-wide scales, 2) incorporate a fully developed suite of social indicators that are tested, standardized and, most importantly, can be compared across watersheds and at varying spatial scales through the expansion of SIDMA, and 3) expand the use of social indicators to guide, and accelerate implementation of state-level nutrient reduction strategies. Social indicators provide consistent measures of social change and can be used by planners and managers to assess change in attitudes towards the implementation of water conservation practices. Social indicators can also accelerate the effective implementation of nutrient reduction strategies.<br /><br /><a href="/conference/pdf/guzman_sandra2016.pdf">Download presentation</a>
Role of SERA-46 in fostering collaboration and improvement toward nutrient reduction goals in the Mississippi/Ohio River Basin
Year: Authors: Baker B., Burger W., Ingram R.
The Southern Extension and Research Activities committee number 46, is one of a group of formal USDA Nation Institute of Food and Agriculture (NIFA) and Land Grant University funded committees designed to promote multistate research and extension activities. SERA-46 was created to provide a framework for collaboration and advancement of priorities with the Mississippi River Gulf of Mexico Watershed Nutrient Task Force (Hypoxia Task Force). Land Grant Universities (LGU) throughout the Mississippi/Ohio River basins are uniquely positioned to assist state agencies and the Hypoxia Task Force in the development and implementation of state level nutrient reduction strategies. Researches as these universities participate in interdisciplinary research ranging from soil science, nutrient transport, water quality, and human behavior, which offer support toward the mitigating nutrient pollution to the Gulf of Mexico to secure water quality for environmental and economic enterprises. In addition to a diversity of scientists, LGUs each have expansive extension units that can assist in disseminating innovative best management practices and solutions to farmers across the basins. Recent strides made by SERA-46 in support of state and Hypoxia Task Force nutrient reduction goals include securing extramural funds to develop a framework for tracking progress toward nutrient reduction goals via reductions in nonpoint sources of pollution, securing funds for watershed capacity building, developing social indicators related to nutrient reduction, and a large-scale transforming drainage project in the Midwest. Mississippi State University has contributed significantly toward advancement of priorities within the state through a semantic analysis of all Mississippi/Ohio River basin Nutrient Reduction Strategies to develop a guideline for optimizing plans toward goals of the Hypoxia Task Force, leading the social indicator development efforts, farmer engagement, farm system sustainability trainings, and BMP efficiency investigations.<br /><br /><a href="/conference/pdf/baker_beth2016.pdf">Download presentation</a>
Can one hundred-year precipitation record produce patterns allowing seasonal weather prediction?
Year: Authors: Buka H., Pote J., Wax C., Linhoss A.
Rainfall prediction remains a scientific and technical challenge, since rainfall is the most difficult element of the hydrological cycle to forecast. Precipitation predictions as produced by the weather services are frequently poor beyond a few days. Using historical precipitation data to predict future rainfall is possible, as rainfall tends to follow previous patterns that can be easily explained through statistical and mathematical procedures. Rainfall is the most important climatic variable on which most crops are dependent. In Mississippi, however, certain climatic phenomena such as El Nino Southern Oscillation (ENSO) comprised of the warm phase (El Nino) and the cold phase (La Nina) can be responsible for irregular climatic changes such as uneven distribution of rainfall, thereby making predictions using past patterns challenging. This study attempted to determine the extent to which rainfall received during six months (September -February) prior to the growing season can be used to predict rainfall during the growing season (March - August). The assumption is that certain patterns might be good indicators of climatic oscillations that could persist. One hundred years of previous precipitation data from the Delta Research and Extension center will be used and statistical equations and analysis will be performed to provide three outputs useful to producers. The outputs include normal climate, average growing season for the closest ten years matching pre-growing season, and the single year that closely matches the current growing season. The results will be shown as 20, 50 and 80 percent probability brackets. This study will address issues such as i) can the second six months' variations be low enough to consider it as a good predictive tool and ii) can established patterns be tied back to teleconnection to make predictions based on those.
Evaluating the effects of irrigation management practices on groundwater recharge and storage in Mississippi Delta
Year: Authors: Gao F., Feng G., Han M., Jenkins J.
The Lower Mississippi River alluvial plain (refers to MS Delta), which is located in the northwest part of Mississippi in the U.S. It is a highly productive agricultural region, groundwater was considerably pumped for irrigating major row crops such as corn, cotton, soybean, and rice. As a result, the groundwater table has decreased dramatically, which threaten the sustainability of irrigated agriculture in the MS Delta. The objectives of this study were: 1) quantifying the amount of groundwater recharge as well as the groundwater storage from precipitation and irrigation return flow; 2) simulating the groundwater recharge and storage as affected by a) conventional irrigation scheme; b) water-saving irrigation scheduling for exactly satisfying crop water requirement using all groundwater; c) water-saving irrigation scheduling using different percentages of surface and ground water. The Soil and Water Assessment Tool (SWAT) was calibrated by the SUFI-2 auto-calibration algorithm in the SWAT-CUP package using observed daily streamflow data from 2003 to 2006,then was validated using measured streamflow data from 2007 to 2010. The model performed well during the calibration period (R<sup>2</sup> ranged from 0.70 to 0.93 and Nash-Sutcliffe efficiency varied from 0.41 to 0.62) for daily streamflow. This study suggested that the conjunctive use of surface and ground water as irrigation sources is a sustainable way for future generations to continuously grow those major row crops in MS Delta.
Species-Specific Environmental Factors that Influence Sap Flow Rates of Nine Bottomland Hardwood Species
Year: Authors: Kassahun Z., Renninger H.
Climate change models predict an increase in prolonged drought events in the southeastern United States. Due to these climate alterations, bottomland hardwood forests could experience a drastic shift in their established hydrological patterns. Individual water consumption of hardwood trees vary by species and can be influenced by environmental factors such as solar radiation, soil water availability, temperature, and atmospheric vapor pressure deficit. These environmental factors are expected to shift in intensity and availability as climate change persists. As these environmental factors shift, certain tree species could be more negatively affected over more resilient species, ultimately leading to a shift in species composition in the forest. The rate of sap flow described as the transport of water that occurs in the xylem of a tree, is indicative of a tree's water use strategy. Sap flow rates can convey how much water a tree is using as well as how the tree copes with limited water resources. By using sap flow measurements to study the species-specific factors that influence physiological response, we can better understand how species specific water use will shift under drought conditions. Sap flow rates were measured using heat dissipation sensors on nine deciduous hardwood species found in a seasonally flooded hardwood forest. Simultaneously, temperature, relative humidity and soil moisture were measured and vapor pressure deficits were calculated. We found that cherrybark oak uses the most water during the growing season, using ~45% more water than the next highest consumer, swamp chestnut oak. Shagbark and pignut hickory use the least amount of water during the growing season, roughly 2% of cherrybark oaks' water consumption. Sap flow rates also exhibited a linear correlation with soil moisture and vapor pressure deficit for American elm, pignut hickory, swamp chestnut oak, and willow oak in order of correlation strength. Response to changes in vapor pressure deficit were also directly linked to the soil moisture conditions for these species. These findings suggest that as drought conditions increase, leading to a decrease in soil moisture, these species will respond with a reduction in sap flow, with American elm and pignut hickory showing the greatest reduction in water use and winged elm exhibiting the least response. This information will be useful in accurately estimating forest water budgets based on future climate change predictions.
Application and validation of STWAVE in the nearshore of Deer Island, MS
Year: Authors: Dillon C., Linhoss A.
Waves are the driving force for many coastal processes. The process of sediment transport along a beach face is highly tied to the presence and action of waves. Therefore, due to the constant sediment transport occurring along Deer Island in Harrison County, MS, and the costly procedures required to maintain the sediment budget of the area, an accurate and full understanding of the wave parameters in the area is important. To date, no validation of a local model or any other published data on the waves for the area exists. Therefore, the purpose of this study is to validate a local model which will be able to be used to forecast or hindcast wave information for present or future work done on Deer Island. To quantify wave parameters of the area a wave model is the best option for its ability to generate high resolution information. For this study, the STWAVE model was chosen because of the mild and uniform conditions of the area and for STWAVE's fast computational efficiency. Field data of recorded wave information was taken from a Nortek Vector which recorded wave and current data between the months of June and September, 2016. The raw data of the Vector will be processed using the PUV method to produce wave height, wave period, and wave direction information. Wave data was also taken during this same time period through littoral environmental measurements (LEM) made at the shoreline. Both sets of gathered wave information will be used to validate the STWAVE model.
Using Deuterium and Oxygen-18 Isotopes to Understand Stemflow Generation Mechanisms
Year: Authors: Siegle-Gaither M., Siegert C.
Stemflow is a nutrient-enriched type of rain partitioning that redirects intercepted water from the forest canopy down tree trunks, creating biogeochemical hotspots at tree bases. Few studies have examined species-specific effects of bark structure and storm meteorological conditions on stemflow generation via stable hydrogen (δD) and oxygen (δ<sup>18</sup>O) isotopic tracers. This study explores these relationships in an oak-hickory stand in central Mississippi. Species were chosen based on their unique bark characteristics and variable effects on rain partitioning. Stemflow volume and isotopic composition were measured over one year with objectives to determine (i) origins and pathways of stemflow water using stable isotopes, (ii) differences in stemflow generation mechanisms between tree species, and (iii) differences in stemflow generation mechanisms between storm events.<br /><br /> Stemflow collars were installed on 18 trees of six species. Water samples were collected within 24 hours of individual storm events. Laser ablation spectroscopy was used to analyze δD and δ<sup>18</sup>O in collected water samples. Results show that isotopic composition (δ<sup>2</sup>H) of stemflow (-20.08±10.18‰) is distinct from that of throughfall (-21.25±9.09‰) and precipitation (-15.49±10.03‰). The difference in isotopic composition of stemflow relative to throughfall and precipitation signifies evaporation, suggesting that this pathway is composed of both pre-event and event water. Bark thickness measurements were greatest in <em>Quercus alba</em>, followed by <em>Q. stellata, Q. shumardii, Q. pagoda, Carya glabra,</em> and <em>C. ovata</em>. Stemflow volumes per basal area followed a similar trend. Greater bark thicknesses correlate with lower stemflow volumes per basal area, advocating that interspecific bark characteristics play an intricate role in stemflow generation. A bark-wetting experiment showed bark water storage capacity (BWSC) per tree stem to be greatest in red oaks (<em>Q. shumardii</em>: 87.4±21.5 L and <em>Q. pagoda</em>: 85.4±21.5 L), then white oaks (<em>Q. alba</em>: 57.2±41.7 L and <em>Q. stellata</em>: 45.5±20.0 L), and hickories (<em>C. ovata</em>: 26.7±24.9 L and <em>C. glabra</em>: 18.6±6.5 L), respectively. Oak species with thick, continuous bark surfaces generate lower stemflow volumes and have higher BWSC; whereas hickory species tend to have thinner, irregular bark structures that lead to higher stemflow volumes and lower BWSC. Specifies-specific BWSC is therefore not only a determining factor for stemflow generation during an event, but also for how much pre-event water is contributing to this flux, both in terms of volume and chemistry. Thus these results show how stemflow significantly impacts forest hydrology and microclimate based on interspecific differences in bark thickness.
Overview of Water Availability in Mississippi
Year: Authors: Phillips P.
The abundant water supplies in Mississippi constitute one of the most important and valuable natural resources in the state. These resources contribute directly to the quality of life and economic prosperity of the state. Throughout the state, there is a need for accurate assessment of groundwater resources to allow wise long-range planning and development. The water resources available in areas of the state can vary significantly depending on various hydrogeologic conditions that may affect baseflow in streams, water quality, and the amount of water local aquifers can supply. The highly variable nature of these resources means that a concerted effort must be maintained to collect related groundwater and surface water data that will allow proper decisions to be made regarding the management and development of the state's water resources.<br /><br /> In Mississippi, precipitation averages about 54 inches annually. About 10% of this infiltrates to the water-saturated zone and becomes groundwater. Fresh groundwater in Mississippi occurs principally in unconsolidated sand and gravel deposits interbedded with thick, extensive layers of clay that form aquifer boundaries and is available throughout the state. Groundwater supplies 90% of water used in the state, for everything from drinking water supplies, agriculture, fish culture, to commercial and industrial uses.<br /><br /> The total volume of fresh water stored in Mississippi's aquifers, which has been conservatively estimated to be in excess of 6 billion acre-feet, dwarfs the total volume of all surface water resources, but surface water is still a valued source of water supply in the state. Mississippi has 10 major river basins with 86,000 miles of streams. Surface water supplies drinking water to five entities: the City of Jackson, the City of Corinth, Short Coleman Water Association, the NE MS Regional Water Supply District, and the Jackson County Port Authority. Surface water is also used for agriculture, industries, and wildlife management, among other uses.<br /><br /><a href="/conference/pdf/phillips_pat2016.pdf">Download presentation</a>
Effects of water use on fish biodiversity: a decision-support framework
Year: Authors: Cartwright J., Wolfe B.
Despite increasing awareness of the importance of streamflow variability to fish communities and efforts to create regional standards for environmental flows, methods are lacking that explicitly translate water-use decisions into predicted ecological outcomes. The U.S. Geological Survey has developed ecological limit functions in the Tennessee River basin relating hydrologic departure from reference conditions to species richness for key fish groups based on trophic and habitat characteristics. These ecological limit functions have been incorporated into a hydrologic accounting framework to allow water-resource managers to examine the consequences for fish biodiversity of water-use decisions, such as withdrawals for municipal or agricultural use. This approach allows various management scenarios to be compared, with the goal of maintaining ecological health of streams and conserving fish biodiversity while optimizing water availability for human use.<br /><br /><a href="/conference/pdf/wolfe_bill2016.pdf">Download the presentation</a>
Nutrient and phytoplankton changes in Roundaway Lake after a managed hydrologic drawdown
Year: Authors: Lizotte, Jr. R.E., Taylor J.M., Locke M.A.
A late summer drawdown of Roundaway Lake in the Mississippi Delta was initiated to help improve downstream flows within the Big Sunflower River. Although such water releases are important to help improve downstream water quality, a better understanding of the changes and processes within the contributing water bodies is needed to aid water resource management decisions. Consequently, we examined the influence of the lake drawdown on surface water nutrients and phytoplankton within the system before, during, and after drawdown. Lake drawdown was initiated on September 15, 2015 and was completed within six days when outflow was <5% of peak flows and channel water depths decreased by 40%, 28%, and 82% at upstream, lake, and downstream sites, respectively. Surface water samples for nutrient and phytoplankton analysis were collected on days -7, -1, 0, 1, 2, 3, 6, 13, 20, 28, and 34 at all three sites. Nutrients included soluble reactive phosphorus (SRP), dissolved inorganic nitrogen (NH4-N, NO2-N, and NO3-N), total nitrogen (TN), total phosphorus (TP), and dissolved organic carbon (DOC). Phytoplankton measurements were: chlorophyll a and in-vivo chlorophyll (phytoplankton biomass); in-vivo phycocyanin (blue-green algal biovolume); chlorophyll:phycocyanin ratio (Chl:PC, blue-green algal bloom); phytoplankton photosynthetic activity (Chl Fv/Fm); and blue-green algal photosynthetic activity (PC Fv/Fm). Surface water nutrient responses were modest with the exception of SRP. Bimodal changes in SRP occurred with decreases at all sites during the initial drawdown phase (days -1 to 6) followed by increasing SRP levels 13 to 34 days after drawdown. No clear trends were observed for dissolved inorganic nitrogen while TN increased with time and changes in turbidity and TP varied with turbidity. Regression analysis identified some of the physical and chemical factors driving phytoplankton responses to the drawdown. Chlorophyll a was associated with TN and N:P ratios (R2 = 0.571), in-vivo chlorophyll was associated with depth, TN, and N:P ratios (R2 = 0.785), and in-vivo phycocyanin was associated with SRP, TN, and N:P ratios (R2 = 0.750). Blue-green algal blooms (Chl:PC) were associated with SRP, NO3-N, and C:N ratios (R2 = 0.645). Chl Fv/Fm and PC Fv/Fm were associated with C:N ratios (R2 = 0.351) and NO3-N + C:N ratios (R2 = 0.338), respectively. These results will provide valuable information that will help water resource managers make better informed decisions to sustain surface water resources and ecosystem integrity of Mississippi Delta rivers and lakes.
Connecting water level to biological health in Alabama streams
Year: Authors: Rose C., Knight R.R., O'Neil P.
Water is critical to the survival of aquatic biota, but little has been done to quantify the minimum water level in a stream that provides adequate support for aquatic biological communities. Most research in this field has focused either on connections between various streamflow measures and aquatic habitat, linkages between aquatic habitat and the biological health of streams, or using the annual or monthly 7Q10 or other low-flow measures to establish minimum flows. Resource managers need a better understanding of the interaction and linkages between streamflow, water level, channel morphology, physical habitat availability (streambed), and biological health to establish scientifically-defensible flow requirements. The proposed analysis will be based on existing streamflow, channel morphology, physical habitat availability, and biological health (richness, diversity, or IBI score) data at each site. The analysis will include, but is not limited to: daily value streamflow time series, streamflow measurement data (cross-section data), game and non-game fish community data, available habitat data, and stream cross-sectional surveys. Existing data from 15 to 20 streams in different physiographic regions of Alabama will then be used to answer the following questions: Is physical habitat quantity maximized at low, yet consistent streamflow? Is the streamflow associated with maximized physical habitat predictable and does it vary regionally according to published geologic and physiographic boundaries? Does biological health of fish communities appear to be correlated with the amount of time streamflow is lower than that associated with the maximized physical habitat?
Prioritizing the restorability of impaired water bodies: A case study of four watersheds in the Delta region in the state of Mississippi
Year: Authors: Sinshaw T., Surbeck C.
The restorability potentials of four impaired water bodies (Lake Washington, Harris Bayou, Coldwater River, and Steele Bayou) in the Delta area of Mississippi were compared in this study using the EPA Recovery Potential Screening tool. A variety of selected indicators under ecological, stressor, and social fields were evaluated. The studied water bodies' restorability potential was ranked based on the most influential indicator score, the aggregated indicator score under each field, and the integrated recovery potential score of the three fields. Restorability scores were calculated based on two scenarios; (1) with indicators assigned with equal weight and (2) with indicators assigned with unequal weight. Agricultural activity, covering 70 to 80 % of the total land use of the studied water bodies' drainage area, was found as the most stressful single indicator. In that regard, Harris Bayou was observed as the most difficult to restore. Based on the aggregated indicator under each field scores, Steele Bayou and Lake Washington were observed with the most and the least favorable biophysical conditions for restorability, respectively. The Coldwater River was observed with the highest social capacity for restorability. The water bodies were also compared based on an overall integrated recovery potential score (IRPS) of the three fields. Coldwater River and Steele Bayou were found as the first and second most restorable water bodies in both the equally and unequally weighted scenarios. Harris Bayou and Lake Washington were ranked as the third and fourth, respectively in the equally weighted scenarios, and fourth and third, respectively in the unequally weighted scenarios. Remarkable rank change between Harris Bayou and Lake Washington in the unequally weighted scenario implies the significant effect of assigning indicator weight on restorability ranking. Based on this rationale, this research suggests further study is needed on the EPA Recovery Potential Screening tool to understand the sensitivity of the restorability potential based on indicator weights.
Brown pathways in green systems: source, habitat and nutrient effects on organic matter breakdown in Mississippi Delta agricultural bayous.
Year: Authors: Testa III S., Taylor J.M., Lizotte R., Dillard K.
Excess nutrient runoff can impact agricultural water bodies but little is known about the role of agriculturally derived organic matter in mediating water quality impacts associated with nutrient enrichment in agricultural landscapes. We compared source, habitat and nutrient enrichment effects on breakdown rates of agricultural field (corn residue) and riparian (willow oak) organic matter in natural bayou ecosystems and stream mesocosms. Field data indicated that breakdown rates for corn were high (k = 0.0321 ± 0.0027 d-1) compared to willow oak (k = 0.0109 ± 0.0033 d-1) in bayous, and, for both species, more hydrologically dynamic inflow sites had significantly lower breakdown rates than lentic sites. Mesocosm results indicated corn residue breakdown rates did not increase with phosphorus (P) enrichment, increased with nitrogen (N) enrichment, but were highest when mesocosms were enriched with N and P (N+P). Willow Oak had much lower breakdown rates than corn residue in mesocosms, confirming species effects observed at field sites. The highest oak breakdown rates were observed in mesocosms enriched with N and P which were significantly higher than control or P enriched streams. Oak breakdown rates in N enriched mesocosms were also significantly higher than control streams but intermediate between P enriched and N+P enriched mesocosms. Respiration rates for corn residue were double that of willow oak and enrichment effects varied with time, but there was clear experimental evidence that N + P enrichment increased respiration for both species. Our results demonstrate that changes from riparian species to more labile crop residue sources of organic matter, combined with nutrient runoff, may impact agricultural water bodies by increasing microbial respiration associated with faster organic matter breakdown rates. However, reductions in nutrient runoff from agricultural areas, as well as increasing buffers of natural vegetation through agricultural best management practices, have the potential to reduce high inputs of crop residue and decrease microbial respiration rates associated with corn residue and nutrient enrichment in bayous of alluvial plain agroecosystems.
Application of AnnAGNPS for Evaluating the Nutrient Loading Control of an On-Farm Water Storage (OFWS) system in East Mississippi
Year: Authors: Karki R., Tagert M.L., Paz J., Bingner R.L.
Irrigation tailwater and storm runoff events from agricultural watersheds are a major source of nutrient loading in rivers and streams. According to the 2012 Mississippi Quality Assessment Report, nitrogen, phosphorus, sediments, and biological oxygen demand are the major pollutants of the Middle Tombigbee-Lubbub Watershed, which includes the study area. An On-Farm Water Storage (OFWS) system is a constructed best management practice (BMP) consisting of a tailwater recovery ditch or terraces and a water storage pond. These OFWS systems have demonstrated the ability to both reduce downstream nutrient loading and provide water for irrigation by capturing and recycling irrigation tailwater and rainfall runoff. The Annualized Agricultural Non-Point Source (AnnAGNPS) surface runoff model is a continuous simulation, daily time step, pollution loading model. This poster will present the preliminary results from the application of AnnAGNPS to estimate nitrate and phosphorus losses from a small agricultural watershed in East Mississippi over a one-year period from fall 2014 to fall 2015. Storm runoff events were captured using an ISCO auto sampler and will be used to calibrate and validate the model results. AnnAGNPS will also be used to estimate the nitrogen and phosphorus loads captured by the OFWS system during the study period. In addition, alternative management practices that could potentially decrease nutrient losses from the agricultural fields will be evaluated using the model.
Water use of dominant Pinus taeda and mid-canopy Liquidambar styraciflua and consequent implications of forest succession
Year: Authors: Hornslein N.
As southeastern forests undergo succession from Pinus taeda (loblolly pine) to hardwoods, differences between water use for these different tree types could alter future conditions of water available in the ecosystem. Investigating loblolly pine and sweetgum (Liquidambar styraciflua) transpiration rates is a necessary step in order to determine if significant changes in water availability in the system will occur during succession. This will have future implications for streamflow, groundwater, and flooding. We hypothesize that sweetgum will use more water per unit sapwood area than loblolly pine and that sweetgum will be more responsive to environmental parameters including soil moisture and atmospheric vapor pressure deficit than loblolly pine. This study was performed in an aging loblolly pine plantation undergoing hardwood succession located on clay soils that experience occasional flooding in central Mississippi. The sap flow of 15 loblolly pines and 12 sweetgums were measured from July to November, 2015 using thermal dissipation probes. The trees sampled vary in size with DBH values ranging from 10.16 cm to 40.13 cm in sweetgums and 35.56 cm to 60.45 cm in loblolly pines. Additionally, environmental variables of vapor pressure deficit and soil moisture were measured to compare with tree-level water use. The slope of sap flow vs. soil moisture was higher in pines, demonstrating that they were more responsive to soil moisture than sweetgums. Both species demonstrated more significant relationships between sap flow and soil moisture than with vapor pressure deficit. On average, during the summer growing season, pine water use was approximately 571 kg m-2 sapwood area day-1 whereas sweetgum water use was approximately 793 kg m-2 sapwood area day-1. Therefore, forest succession from loblolly pine to hardwoods such as sweetgum would result in higher tree water-use leaving less available water in the system.
Research Program at the USDA-ARS National Sedimentation Laboratory: At the Interface of Agricultural and Natural Resource Management
Year: Authors: Locke M.A., Dabney S.M.
For over 50 years, the USDA-ARS National Sedimentation Laboratory, Oxford, MS, ("Sed Lab") has served as a center for research on sediment and erosion issues and is currently the lead USDA-ARS facility addressing (1) watershed erosion and sedimentation processes, and (2) watershed ecological functions as impacted by agricultural practices. The Sed Lab consists of two research units: (1) Water Quality and Ecology, and (2) Watershed Physical Processes. The research program emphasizes interdisciplinary studies dealing with physical, chemical, and biological processes related to natural resources in agricultural watersheds, and assessing strategies for sustaining and enhancing the integrity and function of agro-ecosystems. Specific topics of study include: (1) soil erosion, transport and deposition of sediment in watersheds including stream stability and bank protection; (2) agricultural practice and stream structure impacts on water quantity, water quality, and ecosystem services; (3) movement and fate of chemicals within the landscape; (4) ecosystem integrity of streams and adjacent riparian zones, lakes and wetlands; and (5) processes controlling surface and groundwater movement. The NSL also serves as the lead research facility in the Lower Mississippi River Basin for the USDA-ARS Long Term Agro-ecosystem Research (LTAR) network.
Remediation of Oriented Strand Board (OSB) Process Water
Year: Authors: Dowlatabadi L., Borazjani H.
The process of manufacturing OSB involves a pressing process that releases water and extractives from wood. This type water is known as process water and contains wood extractives, phenol/urea formaldehyde resins, terpenes, and other organic compounds which increase the biological oxygen demand (BOD) and total suspended solids (TSS). In order to discharge this water, it must be treated to reach a regulated discharge levels for BOD and TSS. A 30 day laboratory study with bioreactors filled with OSB process water and treated with air only, air plus fertilizer and air with fertilizer and duckweed were conducted to evaluate the removal of BOD and TSS from this type process water. Three untreated controls were used in this experiment. Significant reduction of BOD occurred for all treated replicates after 30 days. No significant differences observed among treated samples. For TSS, again all treated treatments showed significant reduction but reactors treated with only air showed the highest reduction of TSS. Bacterial population remained sufficient throughout this experiment.
Introducing the Mississippi Water Security Institute (MSWSI)
Year: Authors: Ochs C.A., Sullivan-González D., Young D.B.
Through a generous grant from the Robert M. Hearin Foundation, The University of Mississippi Sally McDonnell Barksdale Honors College has established the Mississippi Water Security Institute (MSWSI). MSWSI is developing an intensive two-week workshop on water security issues in the state, which will be offered to a select group of undergraduate students in honors programs in Mississippi. With abundant natural resources and a growing population, Mississippi is an increasingly favorable place to invest, start a business, and raise a family. MSWSI recognizes that with population and economic growth there will be increasing demand on our freshwater resources. The term "water security" refers to challenges inherent in promoting and linking strong business development with community health with natural resource protection. Clearly, this is a challenge requiring communication among multiple fields and interests - the business community, agriculture, law and public policy, urban planning, engineering, and conservation. Reflecting this complex mosaic of water security concerns, the workshop will facilitate interdisciplinary study and problem solving, and include travel, guest speakers, and independent research. Students in the workshop will become knowledgeable in the availability and quality of freshwater resources in Mississippi, learn to assess how these resources can be used wisely in support of business and community development, and environmental stewardship, and work on skills to effectively communicate what we learn to a broad constituency. In this talk, we will present the framework of our first workshop in May, 2016.
A Dynamic Legal Case Study: Mississippi v. Tennessee - The Interstate Dispute Over Groundwater Resources
Year: Authors: Janasie C.
Water is one of the most essential natural resources globally, nationally, and locally. In the United States, access to and management of water resources are becoming more deliberated, and often contested, as states strive for stakes in this shared natural resource. As the legal framework looks to respond to evolving water issues, interstate disputes are in the forefront as pending United States Supreme Court cases. This talk will discuss existing water laws and policies throughout the continental United States and distinguish between regulation of surface water and groundwater. When people think of water, images of surface water like the Mississippi River come to mind, but a large amount of the water we use on a day-to-day basis is groundwater. The role of states in managing water resources, and especially groundwater, is heating up as consumption and science advance. While states can, and do, work together to share interstate water resources, the Supreme Court of the United States must preside over cases where states disagree. This talk will provide a general overview of water law and the interstate water disputes currently before the Supreme Court, notably Mississippi v. Tennessee. While interstate water disputes are common, Mississippi v. Tennessee is a significant legal case because the Supreme Court has never before decided a state dispute over groundwater. This talk will provide an overview of each state's argument and how interstate water disputes have traditionally been treated by the Supreme Court. In conclusion, the talk will discuss the relevance of pending litigation, as well as thoughts on the future of water law.
Catalpa Creek Watershed Restoration & Protection Project and Watershed DREAMS Center
Year: Authors: Schauwecker T.
The Catalpa Creek Watershed is located in Oktibbeha and Lowndes counties in the northeast region of Mississippi and is part of the larger Tombigbee River Basin. The 28,928 acre watershed contains 31 miles of mainstream perennial stream length. At the HUC-12 level, the watershed includes part of the Mississippi State University Campus, the MSU South Farm research facility and dairy farm, as well as a number of privately owned lands. Research activities of the university and continued development and construction of university lands appear to be a primary driver of stream, ecosystem, and water quality degradation. Catalpa Creek is currently listed by the Mississippi Department of Environmental Quality (MDEQ) as impaired by sedimentation and a TMDL has been developed that sets challenging targets for sediment load reductions. Two MSU facilities on the South Farm are permitted point sources - the Poultry Science Research Center and the Ag Center and Horse Park. MDEQ has ranked the watershed as having a high stressor potential, which means compared to other watersheds in the area Catalpa Creek is a watershed in need of restoration. MDEQ supports four sites in the watershed to monitor its biological health. A comprehensive suite of management practices has been selected to address the agricultural resource concerns identified for the watershed, sedimentation, grazing lands, sustainable forestry, and declining wildlife habitats. In addition to the agricultural resource concerns, urban storm water management is a key need for the watershed and a focus for restoration and protection. MSU's Master Plan (MSU, 2010) contains numerous urban storm water management techniques and approaches, which will be leveraged into the project. The project has a number of unique features. These include an education, experiential learning, and outreach approach that begins by better understanding the behaviors, perceptions, and beliefs of watershed stakeholders; creation of experiential learning opportunities for students; a comprehensive monitoring and assessment approach that includes traditional physical/chemical water quality monitoring, macroinvertebrate habitat assessments, use of indicator species to evaluate ecosystem restoration progress; and social indicators to understand improvements in stakeholder behaviors and perceptions and the effectiveness of educational and outreach activities. Other unique features include analyses and designs to restore the structure and function of Catalpa Creek and for siting storm water retention basins to mitigate downstream storm water impacts. Also, incorporated into the project is a focus on watershed sustainability. Probably, the most ambitious component of the project is to leverage these restoration and protection activities into the establishment of a Watershed DREAMS (Demonstration, Research, Education, Application, Management and Sustainability) Center. Supported by over 18 university units, it is envisioned that the DREAMS Center will demonstrate innovative applied research, sustainable water resources management, and effective and quantifiable education and experiential learning for students, educators, and federal/state conservation agencies and organizations.<br /><br /><a href="http://prezi.com/a696ojtro0ri/?utm_campaign=share&utm_medium=copy" target="_blank">Download the presentation</a>
Collection and analysis of water quality and benthic macroinvertebrate and algal community data to support nutrient criteria development in northweste
Year: Authors: Hicks M.
The Mississippi Department of Environmental Quality (MDEQ) is in the process of developing scientifically defensible nutrient criteria to protect designated uses of three types of waterbodies: lakes, streams/rivers, and estuaries/coastal waters. Data collection and analysis efforts in support of nutrient criteria have been ongoing in some ecoregions in the State since about 2002, and separate Technical Advisory Groups (TAGs) have been formed to oversee criteria development for each waterbody type. Developing nutrient criteria has proven to be particularly challenging in the Mississippi Delta region in northwestern Mississippi. Reference or best attainable conditions have not been fully identified in this region, and complex relations between nutrient concentrations and biological integrity are not well understood. In 2015, the U.S. Geological Survey (USGS) partnered with MDEQ and the U.S. Environmental Protection Agency (USEPA) to conduct a study in wadeable streams that originate in the Bluff Hills along the eastern boundary of the Mississippi Delta for the primary purpose of supporting nutrient criteria development. The main scope of the study involves collection of algal community and biomass data along with concurrent and antecedent physical, chemical and other biological data to characterize stressor-response relationships. The study purpose, strategy, design, and timelines will be presented.<br /><br /><a href="/conference/pdf/hicks_matt2016.pdf">Download presentation</a>
Water Quality in Bangs Lake: effects of recurrent phosphate spills to a coastal estuary: Year 2
Year: Authors: Dillon K., Caffrey J., Carmichael R.H., Dzwonkowski B., Holcomb S., Berry T., Baine G., Sleek J.
In 2015 we continued to examine the effects of industrial phosphate spills to Bangs Lake in the Grand Bay National Estuarine Research Reserve. Higher phosphate concentrations in sediments and porewater were measured in Bangs Lake compared to the reference site in Bayou Heron (while other nutrient concentrations were similar or lower). Peaks in particulate organic phosphorus (POP) concentrations in southeastern Bangs Lake corresponded in time to at least one known major phosphate spill (2005). In an effort to examine transport of a contaminant plume we also conducted a fluorescent dye tracer study using fluorescein in the northern portion of Bangs Lake. Transport and dilution rates on the day of the study were strongly affected by tidal action and a very strong western wind. Although the known source of phosphorus to the estuary is on the western side of Bangs Lake, hydrological processes that flush sediments and nutrients from the Lake may concentrate finer sediments and associated particulate phosphorus in the southeastern part of the Lake. Pb 210/ Cs dating conducted on the sediment cores were corroborated by Th isotope data, which confirmed greater pollution associated with spill material from the facility at sites in Bangs lake. Phytoplankton nutrient bioassay experiments showed that phytoplankton in Bangs Lake were very strongly limited by nitrogen. Preliminary results suggested that both ammonium and nitrate were effective at stimulating growth, and grazing by microzooplankton was sometimes significant. Benthic microalgae in Bangs Lake appeared to be decreasing, although they were still generally higher than at the reference site. Benthic microalgal growth was not stimulated by addition of ammonium, phosphate or both.<br /><br /><a href="/conference/pdf/dillon_kevin2016.pdf">Download presentation</a>
Improving water quality through cost-effective marsh restoration
Year: Authors: Sparks E.L., Cebrian J.
Marshes provide many ecosystem functions and services that are integral for coastal health. One of the most valuable ecosystem services provided by coastal marshes is the removal excess nutrients prior to entering coastal waters. Unfortunately, marsh degradation has led to drastic reductions in the capacity of marshes to provide this nutrient buffering service. As an attempt to mitigate for this reduced nutrient removal capacity, many restoration projects have been and will continue to be conducted. However, the majority of these projects are limited in evaluation of the ecosystem services they provide, cost-effectiveness, and how climate change will affect them. Given the high cost associated with these projects, evaluating the cost-effectiveness and resilience of different designs is necessary for making restoration a more ubiquitous and effective practice. We constructed and evaluated experimental marshes at the Grand Bay and Weeks Bay National Estuarine Research Reserves to test the effectiveness of different initial planting densities at removing nutrient pollution. At the Grand Bay site, we had initial planting densities of 0%, 50%, and 100% of Juncus roemerianus (black needlerush). At the Weeks Bay site, we created marshes in abandoned canals and, within them, planted black needlerush at 5 different densities (0%, 25%, 50%, 75%, and 100%). In half of the Weeks Bay plots, we simulated short term sea-level rise to approximate levels projected at 2030. At both sites we compared porewater concentrations of dissolved inorganic nitrogen (DIN) and used this measurement as a proxy for nutrient removal across all plots. Our findings indicate the 50%, 75%, and 100% planting densities suppress porewater DIN concentrations to similar levels and at significantly greater levels than the 0% and 25% planting densities. Therefore, the 50% planting density is suggested as the most cost-effective design for nutrient removal. Effects of short term sea-level rise on DIN concentrations varied by marsh location, but, in general, did not have a large effect. This information can be used by managers to design more cost-effective restoration projects that take into account the potential effects of sea-level rise.<br /><br /><a href="/conference/pdf/sparks_eric2016.pdf">Download presentation</a>
Optimizing carbon to nitrogen ratios to improve nitrogen removal in agricultural drainage ditches
Year: Authors: Faust D.R., Króger R., Miranda L.E., Cox M.S., Moore M.T., Rush S.A.
The annual occurrence of a hypoxic zone in the Gulf of Mexico is caused by nitrogen loads from the Mississippi River Basin, which includes agricultural drainage ditches. The objectives of these studies were: (1) evaluate how organic carbon amendments affect nitrate-nitrogen removal in agricultural drainage ditch systems using laboratory microcosms, (2) determine effects of organic carbon amendments and flow rate on nitrate-nitrogen removal in a semi-controlled field setting using experimental drainage ditches, and (3) assess relationships between organic carbon and nitrogen content of overlying water, pore water, and sediments of drainage ditches throughout the Lower Mississippi Alluvial Valley. In laboratory experiments, nitrate-nitrogen removal in dissolved and particulate organic carbon treatments was greater than 90% compared to as low as 60% in control treatments. The optimal carbon-to-nitrogen ratio of organic carbon amendments for efficient nitrate-nitrogen removal was 5:1. Experiments in experimental drainage ditches revealed that flow substantially lowered the ability of organic carbon amendments to remove nitrate-nitrogen with a maximum percent nitrate-nitrogen reduction of 31.6% in a dissolved organic carbon treatment, although implementation of low-grade weirs in experimental drainage ditches did result in removal of nitrate nitrogen in all treatments and at all flow rates. Examining the nitrogen and organic carbon contents in agricultural drainage ditches throughout the Lower Mississippi Alluvial Valley revealed that organic carbon content in overlying water, pore water, and sediments are lower than observed in other wetland-like ecosystems and indeed may be limiting denitrification and other nitrogen removal processes. Increasing organic carbon content overall could be achieved by using organic carbon amendments, but this body of research highlights that additional studies are necessary to ensure successful implementation of organic carbon amendments that reach their greatest potential as a management practice to effectively remove nitrate-nitrogen in the realistic settings of agricultural drainage ditches.<br /><br /><a href="/conference/pdf/faust_derek2016.pdf">Download presentation</a>
Mississippi's Approach to Address Declining Groundwater Levels
Year: Authors: Whittington K.
Groundwater levels in the aquifer used for irrigation in the Mississippi Delta are declining as irrigation demands have increased. By law, the Mississippi Department of Environmental Quality (MDEQ) is charged with conserving, managing, developing, and protecting the state's water resources. MDEQ is working with those in the Delta through the Delta Sustainable Water Resources Task Force to identify solutions. A Voluntary Metering Program is being implemented to get accurate withdrawal information and irrigation water management practices proven to save water, time, and money are being promoted. Progress must be made now with voluntary measures while all options continue to be investigated.<br /><br /><a href="/conference/pdf/whittington_kay2016.pdf">Download presentation</a>
Water availability in the Mississippi River alluvial plain: optimized monitoring and modeling for water management
Year: Authors: Barlow J.R., Haugh C.J.
The Mississippi River alluvial plain in northwestern Mississippi (referred to as the Delta), once a floodplain to the Mississippi River covered with hardwoods and marshland, is now a highly productive agricultural region of large economic importance. Water for irrigation in the Delta is supplied primarily by the Mississippi River Valley alluvial aquifer, and although the aquifer has significant storage capacity, there is evidence that the current rate of water use is exceeding the available supply. Groundwater modeling has shown that increasing withdrawals from the aquifer are having a direct impact on the interaction between the groundwater and surface-water systems. Groundwater level declines in the aquifer have resulted in decreased discharge to streams within the Delta to the extent that many stream reaches are presently net-losing streams throughout the year. This decrease in available groundwater discharge is directly impacting many ecosystem services such as maintaining baseflow conditions in streams; regulating temperature regimes for aquatic biota; and buffering contaminant transport at the streambed interface. To better understand and optimize water management and monitoring activities in the Delta, the U.S. Geological Survey and the Mississippi Department of Environmental Quality are collaborating to update and enhance an existing regional groundwater flow model. The model will be used to develop and assess conjunctive water-management optimization scenarios as well as improve and optimize current and future monitoring activities within the Delta. Key revisions include updating the model through 2014 with more recent water use, precipitation and recharge data, and streamflow and water-level observations. In fiscal year 2016, the updated model will be used to develop selected alternative water-supply scenarios to assess relative impacts to the alluvial aquifer and identify data needs for future optimization modeling.<br /><br /><a href="/conference/pdf/barlow_jeannie2016.pdf">Download presentation</a>
Irrigation Water Management Strategies that Improve Crop Yield and/or on Farm Profitability
Year: Authors: Krutz L.J., Pickelmann D., Atwill R., Leininger S., Bryant C., McNeal J., Wood W., Henry M.
The Row-crop Irrigation Science Extension and Research (RISER) program has demonstrated how Irrigation Water Management (IWM) practices including computerized hole selection, surge irrigation, soil moisture sensor (SMS) technology, and alternate wetting and drying (AWD) reduces irrigation water use up to 40% while improving profitability by $40/acre. However, very few Mid-South irrigators are using IWM practices. The objectives of this session are to 1) illustrate how computerized hole selection and surge irrigation improves irrigation application efficiency; 2) describe how SMS technology improves irrigation scheduling decision for initiation and termination; 3) inform practitioners how AWD impacts water use, yield, weed control, and N uptake 4) examine on-farm case studies where IWM practices significantly improved corn, soybean and rice yield/profitability. <br /><br /><a href="/conference/pdf/krutz_jason2016.pdf">Download presentation</a>
Managed Aquifer Recharge and the Mississippi River Alluvial Aquifer: On-farm and Regional Perspectives
Year: Authors: Rigby J.R., Barlow J.
Groundwater from the Mississippi River Valley Alluvial Aquifer (MRVAA) is the primary source for irrigation in the Delta. Withdrawals in excess of recharge in recent decades have resulted in declining groundwater levels, particularly near the central Delta. Irrigated agriculture has reached the point such that to achieve sustainability the aquifer must be managed carefully as a finite, yet renewable, resource. Management of groundwater resources is most often associated with managing withdrawals, e.g., through more efficient water use and development of alternative surface water resources. Equally, though, aquifer recharge is a part of the management equation. Managed Aquifer Recharge (MAR) is increasingly the guiding paradigm for groundwater resources in arid regions. MAR has not received the same attention in humid regions where the supply of water usually far exceeds the demand. In an intensively developed system like the MRVAA, however, emphasis on managing recharge is a crucial component of sustainable water resources. This presentation will examine the hydrologic dynamics of recharge to the MRVAA at farm and regional scales. The merits and challenges of a suite of techniques for managing aquifer recharge including recharge basins, vadose wells, aquifer storage and recovery, and groundwater transfers will be outlined as they relate to the MRVAA.<br /><br /><a href="/conference/pdf/rigby_jr2016.pdf">Download presentation</a>
Bio-inspired energy and water recovery from low substrate wastewaters
Year: Authors: Gude V.G., Stuart-Dahl S.
The energy and water production issues are intertwined and cannot be addressed in isolation. Wastewater treatment and desalination, in particular, are energy consuming processes which can have detrimental effects on the environment. Integrated solutions that utilize waste sources to generate energy, which in turn, can be used to produce freshwater are attractive options to address current energy and water issues. In this context, bioelectrochemical systems have evolved as a novel technology to convert wastes into valuable forms of energy. Bioelectrochemical systems can be employed to generate clean electricity, or high value energy or chemical products from various wastewater sources and organic or inorganic wastes that can serve as fuel feedstock for electroactive bacteria. Microbial desalination cells (MDCs) are based on an integrated configuration in which, wastewater and saline water sources can be treated simultaneously without any external power input or mechanical energy or pressure application. This process offers multiple benefits of energy and resource (water and nutrients) recovery while eliminating environmental pollution. In this research, low substrate synthetic wastewaters with chemical oxygen demand (COD) less than 300 mg/L were treated at different concentrations in microbial desalination cells. A process optimization model was utilized to study the performance of the photosynthetic microbial desalination cells. The variables include substrate concentrations, total dissolved solids, and algae concertation in the cathode chamber. Relationships between the COD concentrations, algae and salt concentrations was evaluated. Power densities and potential energy benefits from algal biomass growth were calculated. This presentation will provide a discussion on the suitability of MDCs for treating low substrate wastewaters such as agricultural wastewaters, anaerobic digester effluents and septic tank effluents for net energy production and water desalination.<br /><br /><a href="/conference/pdf/gude_veera2016.pdf">Download presentation</a>
Solar powered multi-stage natural vacuum low temperature desalination process
Year: Authors: Steinwinder J., Martinez-Guerra E., Guerra H., Spiller B., Byrd C., Solis M., Gude V.G.
Desalination has emerged as a viable alternative for water supply in many water-stressed regions of the world. In US, some of the states such as California, Texas and Florida are faced with major challenges of ensuring adequate water supplies to meet the demands as a result of population growth, severe drought, decreasing aquifer levels and increasing industrialization. Desalination can be performed through membrane and thermal processes. These processes are energy-intensive. Powering the desalination processes through conventional energy sources is not a sustainable approach as these sources are not renewable. Utilization of renewable energy such as solar energy for water desalination is an ideal approach for thermal desalination processes. In this research, a low temperature desalination process operating at near-vacuum pressures was studied. Near vacuum pressures are created by exploiting the barometric head and gravitational force. As a result, this process reduces the specific energy consumption for freshwater production due to reduced heat losses to the ambient. This allows for efficient utilization of solar energy. Preliminary data of a multi-stage (3 stages) solar powered low temperature desalination process will be presented. Working principles of the novel desalination process as well as energy and mass balances, heat and mass transfer analysis will be presented. Solar collectors will be used to provide the thermal energy required for the desalination process. Our preliminary economic analysis shows that when this desalination system is powered by a low grade flat plate solar collector heat source, the desalination costs are less than $7/m3 which falls in acceptable range for small scale desalination systems of similar capacity. When using a cheap waste heat source purchased at $0.5/GJ, the desalination costs can be reduced to $3/m3. Most small scale domestic desalination systems are designed in combination with a renewable energy source.<br /><br /><a href="/conference/pdf/steinwinder_jeff2016.pdf">Download presentation</a>
Mississippi Private Well Populations
Year: Authors: Barrett J.
Most residents of Mississippi are served by one of the over 1,200 public water systems. Having access to a public water system provides citizens with safety and quality of water through the regulatory enforcement of the Mississippi State Department of Health-Bureau of Public Water Supply. Mississippi citizens on private wells do not have the luxury of knowing the quality and/or quantity of their water on a regular basis. Unfortunately, a reliable method for determining the population that depends on a private well for their water supply has not existed since the 1990 census. This presentation will compare currently available methods and present a new methodology for estimating private well usage in Mississippi. This method uses connections reported to the Safe Drinking Water Information System adjusted to account for non-residential connections, along with census data to generate improved estimates that are quite different from other available sources. This method has been used to generate well usage estimates for all counties in Mississippi. The concluding data can be utilized to better strategize water infrastructure improvements and well monitoring programs. This study should be of interest to representatives of local municipal water systems, local communities, and rural water associations for potential expansion of their water systems. The expansion of a public water system may achieve multiple goals. Additional customers generate more revenue of the public water system, as well as provide a larger customer base in which to spread costs. The regulatory oversight of public water systems should promote and produce a safer drinking water supply for Mississippi residents.<br /><br /><a href="/conference/pdf/barrett_jason2016.pdf">Download presentation</a>
Mississippi's Priority Framework
Year: Authors: Clark S.A.
The Mississippi Department of Environmental Quality (MDEQ) has developed a new collaborative framework for implementing the Clean Water Act. The new framework is designed to help coordinate and focus various efforts to advance the effectiveness of the water program. Given resource constraints and competing program priorities leveraging resources and coordinating efforts is crucial. This new framework does not change regulation, policy or issue new mandates. It is intended to provide focus for MDEQ water programs to better manage the activities and promote collaboration to achieve water quality goals for the streams, rivers, lakes and estuaries of Mississippi. <br /><br /><a href="/conference/pdf/clark_shawn2016.pdf">Download presentation</a>
The Gulf of Mexico Alliance Water Resources Team Update
Year: Authors: Caviness-Reardon K.
The Gulf of Mexico Alliance (GOMA) was established in 2004 by the Gulf State Governors in response to the President's Ocean Action Plan. It is a State-led network of partners working together on projects related to the priority issues identified by the Governors of the five Gulf States. GOMA is a partnership of the five U.S. Gulf States, federal agencies, academic organizations, businesses, and other non-profits in the region. GOMA's mission is to significantly increase regional collaboration to enhance the environmental and economic health of the Gulf of Mexico. In 2014, after careful consideration and evaluation, the GOMA Alliance Management Team elected to modify the priorities supported by the GOMA partnership. Important to note is that none of the existing focus areas were eliminated, but were redistributed within the new team structure. One of the new teams to emerge from GOMA's restructure is the Water Resources Team, a combination of the former Nutrients and Water Quality Teams. The GOMA Water Resources Team is led by the Mississippi Department of Environmental Quality and will focus its efforts within three areas: (1) protection of human health, (2) protection of aquatic health, and (3) protection of economic health. The team will be focusing on various water resources issues across the Gulf including but not limited to hypoxia, nutrient pollution, pathogens, harmful algal blooms, freshwater inflows, and ultimately, working to increase understanding regarding how impacts to human health and aquatic health tie in directly to the economic health of the region. GOMA is currently developing Governors' Action Plan III for Healthy and Resilient Coasts, the third in a series of action plans to address issues common to all five Gulf States in a voluntary and cooperative way.<br /><br /><a href="/conference/pdf/cavinessreardon_kim2016.pdf">Download presentation</a>
Land-use impacts on water quality in Beasley Lake Watershed, Mississippi using AnnAGNPS
Year: Authors: Yasarer L.M., Bingner R.L., Locke M.A., Lizotte R.
Land-use in agricultural watersheds has a fundamental role in shaping hydrologic processes, erosion, and nutrient export. However, changing land-use can be a challenge when assessing the effects of specific agricultural management practices on overall watershed water quality. On a practical level, this challenge often arises from a lack of data describing field-scale land-use and management practices over time. In this study, detailed land-use and management data from 1995-2009 are utilized to conduct AnnAGNPS watershed simulations for Beasley Lake Watershed located in the Mississippi Delta. AnnAGNPS is capable of estimating field-scale sediment and nutrient export on various spatial and time scales, which allows for spatial and temporal analysis of the effects of land-use change. Two major changes in land-use occurred in the watershed over the study period: 1) a change from predominantly cotton to soybean-rotations in 60% of total watershed cropland, and 2) a change from predominantly cotton to Conservation Reserve Program (CRP) practices in 23% of total watershed cropland. The impacts of these two land-use changes will be examined by comparing nutrient and sediment export at the field-level, as well as overall watershed loads throughout the study period. Results from this study will help understand the effect of overall land-use changes on pollutant loads impacting water quality in the Mississippi Delta, where a general decrease in cotton land-use has occurred from 1999 - 2009, coinciding with an increase in soybean and corn land-use. The information from this study can be helpful to conservationists when developing management plans that incorporate effective conservation practices to improve watershed water quality.<br /><br /><a href="/conference/pdf/yasarer_lindsey2016.pdf">Download the presentation</a>
Functions of wetland plant assemblages in water quality improvement
Year: Authors: Windham E.L., Shoemaker C.M., Ervin G.N.
As wetland restoration continues, an understanding of drivers of natural wetland function becomes increasingly important for effective wetland restoration planning. Many studies have shown that wetlands act as filters for nutrient rich waters, in part due to macrophyte properties. Differences in plant characteristics such as biomass production, root oxygen release, and surface area available for microbial colonization have been suggested as possible contributors to greater nutrient removal. Thus, it is assumed that water quality parameters will vary among plant species assemblages, and that differences observed will correlate with one or more aspects of plant species biology or ecology that may prove useful in planning future restorations. Differences have been found in nitrogen removal rates among plant species in studies of monocultures grown in mesocosms mimicking wastewater treatment constructed wetlands, but almost no research has been done on assemblages in natural or restored wetlands. This study aims to identify the differences in water quality improvement among plant assemblages in natural and restored wetlands. Thirty natural and restored wetlands in the Mississippi portion of the Mississippi Alluvial Valley were sampled four times. Dissolved oxygen, temperature, pH, conductivity, turbidity, and oxidation-reduction potential were measured on-site, and water samples were taken for analysis of nitrogen and total suspended solid content.Results showed that water quality parameters such as nitrate and phosphate concentrations, and pH were significantly correlated with plant growth form, in addition to being influenced by wetland type or by nutrient inputs on the surrounding landscape.
Interspecific ecological and meteorological controls on forest canopy-derived hydrology and biogeochemistry in the southeastern United States.
Year: Authors: Siegert C.M., Limpert K.E., Karunarathna A.A.
During storm events, as precipitation moves through the forest canopy it is transformed in both quantity and quality, thus delivering highly enriched water to the forest floor. Throughfall is spatially distributed beneath the forest canopy while stemflow is localized to the roots and soils in the immediate vicinity of individual tree trunks. Previous research has demonstrated that storm characteristics (e.g., intensity, duration, and magnitude), canopy structural parameters, and species composition have a significant control on canopy-derived nutrient fluxes. However, in the southeastern United States, contributions of the forest canopy to nutrient cycling have largely been overlooked, although the magnitude of tree biodiversity in the region separates these forests from their more-studied counterparts. Therefore, a field study was established in an oak-hickory forest in Mississippi to categorize the interspecific control on canopy-mediated nutrient cycling during precipitation events. Throughfall collectors and stemflow collars were located underneath the canopies of four oak (Shumard, Southern Red, Post, and White) and two hickory species (Shagbark and Pignut), with three replicates for each species. Hydrologic flux and nutrient samples were collected following individual precipitation events beginning in Fall 2014 and continue to present. Meteorological characteristics and precipitation chemistry were collected at a nearby open site. Preliminary results indicate that stemflow volumetric flux was significantly different between species (p<0.001) but throughfall volumetric flux was not (p=0.624). Among the oak species, Shumard oak partitioned an average of 73.6% of incident precipitation into throughfall and 1.6% into stemflow, the largest among all species, with the remaining 24.8% partitioned into canopy interception. Mean concentrations of total nitrogen (TN) in throughfall were greatest in Shumard oak (1.44 mg/L) and post oak (1.39 mg/L) while stemflow concentrations were greatest in shagbark hickory (1.81 mg/L) and white oak (1.20 mg/L) and intermediate in Shumard oak (0.96 mg/L). Dissolved organic carbon (DOC) concentrations in throughfall were significantly different than precipitation (p=0.038) but not between species (p=0.342), while DOC concentrations in stemflow were significantly different than precipitation (p<0.001) and between species (p<0.001). Results suggest that Shumard oak canopies facilitate the largest hydrologic fluxes in oak-hickory forests that correspond to intermediate biogeochemical fluxes of nitrogen, enabling this species to directly modify the substrata and its growing conditions. Improved understanding of species-specific roles in nutrient cycles in highly diverse southern forests is critical to developing effective management strategies to mitigate shifts in species composition and ecosystem functions as regional climates change.<br /><br /><a href="/conference/pdf/siegert_courtney2016.pdf">Download the presentation</a>
Effects of land use on wetland plant diversity in Mississippi
Year: Authors: Shoemaker C.M., Windham E.L., Ervin G.N.
Restoration of former agricultural lands to wetlands has increased in the past 25 years, with public and private programs subsidizing the conversion of marginal farmland into wetlands. These wetlands were constructed with structural and functional goals in mind, such as increasing biodiversity and water quality within local and regional watersheds. While successful in terms of area restored, restored wetlands frequently do not meet desired management goals; often, these wetlands resemble highly degraded wetlands in terms of structure and function. While on-site parameters and management recommendations have recently received much attention, desired structural and functional components continue to fall short of management expectations. This study examined relationships between wetland site characteristics, measures of plant diversity, and land use. Data were collected in a total of 30 restored and naturally occurring wetlands in the Delta region of Mississippi during the 2014 and 2015 growing seasons. Wetland sites were surveyed twice during each growing season (May and August) from 50 evenly spaced observation points per wetland. Lower levels of plant diversity were observed in natural, compared to restored wetlands, with hydroperiod and management activities clearly affecting assemblages. Additionally, land use impacted observed plant community metrics, with the prevalence of agricultural and developed lands showing a negative relationship with plant species diversity. Wetland plant diversity showed a strong positive correlation with fallow land cover surrounding wetlands, with fallow land most often corresponding to land placed in conservation easements. Results thus suggest that low-intensity land use buffers associated with conversation easements are having a positive impact on wetland plant species diversity in the Mississippi Delta.<br /><br /><a href="/conference/pdf/shoemaker_cory2016.pdf">Download the presentation</a>
Tapping into Underground Water in Mississippi
Year: Authors: Killebrew R.
An adequate supply of safe water is essential to the public health and welfare. The use of that supply through properly constructed and maintained water wells is an important component in the protection of our groundwater resources. The MDEQ Office of Land and Water Resources is responsible for licensing and regulating all drillers and pump installers operating in the state. Individuals desiring to engage in the business of water well contracting in the state must obtain a water well contractor's license. Those who drill boreholes or wells must obtain a restricted driller's license that will be valid only for a specified drilling purpose. Individuals who service or install water well pumps must obtain a pump installer's license. All licensees must meet specific requirements and demonstrate their competency in drilling and/or pump installation by passing various tests administered either by the MDEQ or by the National Groundwater Association (NGWA). Driller's logs submitted in accordance with our laws and regulations are essential in providing important information for the characterization of our resources and for the proper abandonment of wells.
Irrigation in North Mississippi?
Year: Authors: Tagert M.L., Karki R., Paz J.
The majority of water permits in the state of Mississippi, by far, are for groundwater wells used to supply water for irrigated cropland in the Delta. These wells are fed by the shallow Mississippi River Valley Alluvial Aquifer (MRVAA), which is easily accessible and has supplied water for irrigation since roughly the 1970's. Groundwater levels in the MRVAA have been declining in recent years as the number of irrigated acres in the Mississippi Delta continues to increase each year. As a result, much attention has been placed on maintaining the sustainability of the MRVAA and thus the sustainability of agriculture in the Mississippi Delta. However, an increasing number of producers in North Mississippi have been implementing irrigation to reduce risk during periods of drought and also to increase crop yields. North Mississippi producers face somewhat unique challenges when converting from dryland production to an irrigated system. This presentation will better quantify irrigation practices in North Mississippi and discuss some of the challenges and opportunities North Mississippi producers encounter when implementing irrigation.<br /><br /><a href="/conference/pdf/tagert_marylove2016.pdf">Download presentation</a>
An Overview of Dam Safety and Impoundment Permitting
Year: Authors: Myers D.
There are approximately 7,000 dams in the State of Mississippi that form lakes that are 5 acres or greater in surface area. The State Dam Safety program which is part of the Department of Environmental Quality's Office of Land and Water Resources is responsible for regulating these dams. These dams and lakes not only pose potential threats to lives and property, but can also alter the flow regime of Mississippi streams. Dams which are on inventory are classified as high, significant, or low hazard depending on what would be flooded downstream if the dam were to fail. One aspect of permitting impoundments includes consideration of impacts to minimum flows. Many impoundments are small and located in the upper reaches of watersheds. The small watersheds they impound typically have very low 7Q10 flows and have not been required to have minimum flow devices installed to bypass the 7Q10.<br /><br /><a href="/conference/pdf/myers_dusty2016.pdf">Download presentation</a>
Office of Land and Water Resources: Overview of Water Use In Mississippi
Year: Authors: Hawkins C.
Currently, there are approximately 23,000 groundwater withdrawal permits and 2,600 surface water permits that are active in the state. Seventy-six percent of these permits are issued for irrigation purposes, with the other twenty-four percent leaning heavily on public water supply and other various beneficial uses. The Mississippi Water Law states that all water, whether occurring on the surface of the ground or underneath the surface of the ground, is among the basic resources of this state, belongs to the people of this state, and is subject to regulation. The general welfare of the people of the State of Mississippi requires that the water resources of the state be put to beneficial use to the fullest extent of which they are capable, that the waste or unreasonable use, or unreasonable method of use of water be prevented, and that the conservation of such water be exercised. With only a few exceptions, anyone who wishes to use the waters of the state must obtain a permit from the Mississippi Environmental Quality Permit Board. The OLWR is charged with the task of permitting all groundwater and surface water withdrawals in the state. Other laws that impact the use of water in Mississippi include water well licensing and impoundments, which are also regulated by the OLWR.<br /><br /><a href="/conference/pdf/hawkins_chris2016.pdf">Download presentation</a>
Overview of Water Availability in Mississippi
Year: Authors: Phillips P.
The abundant water supplies in Mississippi constitute one of the most important and valuable natural resources in the state. These resources contribute directly to the quality of life and economic prosperity of the state. Throughout the state, there is a need for accurate assessment of groundwater resources to allow wise long-range planning and development. The water resources available in areas of the state can vary significantly depending on various hydrogeologic conditions that may affect baseflow in streams, water quality, and the amount of water local aquifers can supply. The highly variable nature of these resources means that a concerted effort must be maintained to collect related groundwater and surface water data that will allow proper decisions to be made regarding the management and development of the state's water resources. In Mississippi, precipitation averages about 54 inches annually. About 10% of this infiltrates to the water-saturated zone and becomes groundwater. Fresh groundwater in Mississippi occurs principally in unconsolidated sand and gravel deposits interbedded with thick, extensive layers of clay that form aquifer boundaries and is available throughout the state. Groundwater supplies 90% of water used in the state, for everything from drinking water supplies, agriculture, fish culture, to commercial and industrial uses. The total volume of fresh water stored in Mississippi's aquifers, which has been conservatively estimated to be in excess of 6 billion acre-feet, dwarfs the total volume of all surface water resources, but surface water is still a valued source of water supply in the state. Mississippi has 10 major river basins with 86,000 miles of streams. Surface water supplies drinking water to five entities: the City of Jackson, the City of Corinth, Short Coleman Water Association, the NE MS Regional Water Supply District, and the Jackson County Port Authority. Surface water is also used for agriculture, industries, and wildlife management, among other uses.
Current Surface Water and Groundwater Studies in the Central Mississippi Region
Year: Authors: Henley L.
The Central Mississippi Region encompasses twenty counties and is home to many major cities, including the Jackson Metro area. Both surface water and groundwater studies are currently being conducted in the Central Region. The Office of Land and Water Resources conduct streamflow measurements in order to obtain surface water discharges to complement data collected by the Office of Pollution Control for the M-BISQ (Mississippi Benthic Index of Stream Quality) Program. The 2015-2016 M-BISQ study has approximately forty sites selected within the central region of the state. Regional groundwater studies are also performed by the Office of Land and Water Resources' Water Resources Management Division. The data collected for the regional studies include water level measurements, which are used to create potentiometric surface maps and hydrographs, water quality samples, and using geophysical logs to create geologic cross-sections and maps. Due to rapid expansion in Madison County in both the residential and industrial sectors, Central Region studies are presently being focused on the Gluckstadt area. Primary aquifers utilized in Madison County, specifically in the Gluckstadt area, are the Cockfield and Sparta Aquifers, with some minor use of the Meridian-Upper Wilcox aquifer. Population, water use, and water level data will be assessed to determine any impacts on water availability in the area.<br /><br /><a href="/conference/pdf/henley_lyndsey2016.pdf">Download presentation</a>
Regional Overview of Work by the Water Resources Division in Northeast Mississippi
Year: Authors: Banks J.
Groundwater and surface water resources in the northeast region are monitored by a regional hydrogeologist assigned to the twenty counties included in the area. Historically, the primary focus in the region has been monitoring of water levels in the area's aquifers. Potentiometric mapping of the Paleozoic and Cretaceous aquifers was completed in 2011. Work in the region involves aquifer characterization, including subsurface mapping, water quality sampling and continued water level monitoring. A study of the Wilcox aquifers in Lafayette County will be completed when water quality sampling at selected locations is finished and the data have been analyzed. Smaller, more localized projects for water supply analyses have also been completed, including monitoring water levels in the Tupelo area and in the Wilcox aquifers of Choctaw County. OLWR also works with the Office of Pollution Control collecting surface water discharges for the M-BISQ (Mississippi Benthic Index of Stream Quality), with approximately 56 sites selected within the northeast region of Mississippi. Beginning in July, 2015, each of the four regions is responsible for adequately characterizing the water resources for one area in the region per fiscal year. These areas can be from the size of a small town to as large as a county. Characteristics to be analyzed include water availability, water quality, and water use.<br /><br /><a href="/conference/pdf/banks_john2016.pdf">Download presentation</a>
Evaluations of Groundwater Resources of Southern Mississippi
Year: Authors: Hoffman J.
Virtually all water used for public and domestic drinking water supplies in southern Mississippi is derived from underground sources. Much of the area is underlain by a thick section of fresh water-bearing sediments and multiple aquifers are available at most locations. Although some wells in Wayne and Jones Counties are screened in other aquifers, the most widely used aquifers in southern Mississippi are developed in beds of sand that occur within sediments above the Vicksburg Group. Southwest of a line from Warren County through Wayne County, these sediments dip in a general gulfward direction at rates ranging from 30 to 100 feet per mile and form a wedge thickening southward to more than 5,000 feet in southern Hancock County and southwestern Wilkinson County. The aquifers within this interval have been termed the "Miocene aquifer system". Because these deposits range from late Oligocene to Pliocene age, it is proposed that the name Grand Gulf aquifer system is more appropriate. Fresh water is available from these aquifers nearly everywhere within the 17,000 square mile area of their occurrence, even extending out from the coast beneath the barrier islands along Mississippi Sound and beyond, possibly as deep as 2,500 feet at Ship and Cat Islands. For years, there was little effort to systematically subdivide the many sand intervals that function as separate aquifers within the Grand Gulf system, an interval often consisting of 2,000 feet of fresh water-bearing sediments. Because of the growing need to make informed decisions concerning water use, staff initiated a study to delineate the individual aquifer units within the Grand Gulf system from interpretations of borehole geophysical logs. Office of Land and Water staff members have measured water levels and collected water samples in wells throughout southern Mississippi for many years. In early 1992, investigation of the potential for intrusion of saltwater into the aquifers that are sources of drinking water along the coast started. Results of this investigation found no evidence of saltwater intrusion in the confined aquifers that are sources of water supplies along the coast. In 2011, after reports of increased mineral leasing activity in southwestern Mississippi associated with fracking and its attendant requirements for water, the staff began a study focusing on potential groundwater availability in Amite and Wilkinson Counties that identified the specific aquifer intervals already being used for public and domestic drinking water supplies and those which might supply water for fracking without resulting in adverse impacts upon others.
Quantifying water dynamics in a no-till vs. conventional-till corn field in the Mississippi Delta
Year: Authors: Anapalli S.S., Fisher D.K., Reddy K.N., Sui R., Gowda P.H.
Conventional-till (CT) cropping system reportedly conserve less soil water compared with no-till (NT) soil-residue management. Reductions in evapotranspiration (ET) and runoff (RO) result in increasing infiltration rates of precipitation and irrigation water inputs; however, location-specific benefits from such systems vary with soil texture and presence or absence of restrictions to water movement such as hard pans in the soil profile. One of the primary benefits of NT over CT comes from its potentially decreasing the ET loss of water from the system. Also of importance is the amount of water infiltrated into the soil and available for crop uptake, and how much water is percolated beyond the root zone of the crop contributing to ground water re-charge as this ground water is the main irrigation water source in the region for crop production. Limited research on ET and soil water dynamics beyond the crop root zone in these cropping systems in the Mississippi Delta region preclude farmer tillage recommendations in cropping systems, especially under corn, a relatively new crop in the region. To fill this gap, we embarked on a research program to monitor ET and soil water dynamics along with crop growth physiology changes in corn under NT and CT in a Dundee silt loam soil at Stoneville, MS. The ET estimation is by solving an energy balance equation representing a crop canopy-land surface for latent heat flux from estimates of sensible, soil heat, and net radiation fluxes. Soil heat flux was quantified from measurements of heat flux using a soil heat flux plate installed at a depth of 8 cm and soil temperature and moisture measurements above the plate. The sensible heat was quantified by modeling aerodynamic and boundary layer resistance corrected for atmospheric stability and wind speed effects from measurements of net radiation, air temperature and relative humidity, land surface-canopy temperature, and wind speed at a constant height of 1 m above the crop canopy, and similar data from a nearby eddy-covriance station. We have tested the ET algorithm developed, with simulataneous measurements of ET using a field lysimeter (3X3X2.4m) and energy balance in the center of a 4.4 ha cotton field at Bushland, TX, and found good agreement between the two estimates.
Eddy Covariance Systems for Water Management Research and Agroecosystem Monitoring
Year: Authors: Sui R., Reddy K., Anapalli S., Murrell C.
There is around 1300 mm of annual precipitation in Mississippi. However, uncertainty in amount and timing of precipitation during the crop growing season becomes a serious risk to Mississippi producers. To reduce the risk and optimize crop yield, the producers have become reliant on irrigation. In recent years, irrigated acreage is rapidly increasing in Mississippi. Almost all irrigation water in this region is pumped from the Mississippi River Valley Alluvial Aquifer, and excessive withdrawals of underground water have resulted the level of the aquifer declining. Novel irrigation techniques and tools are needed for improving water use efficiency to maintain Mississippi water resource sustainability. Eddy covariance (EC) method is capable of measuring exchanges of carbon dioxide, water vapor, methane, and energy between the surface of the earth and the atmosphere. Eddy covariance systems have been widely used for monitoring agroecosystems and measuring crop evapotranspiration (ET) for irrigation scheduling. Objectives of this project were to use EC systems to monitor the agroecosystem and measure evapotranspiration for research on water management technologies and agroecosystem assessment. Three EC systems were set up in the Mississippi Delta for agroecosystem monitoring and assessment, and evapotranspiration (ET) measurement. One EC system is located in Stoneville, MS and two others in Arcola, MS. The EC system consisted of a CH4 analyzer for measuring methane gas flux, CO2/H2O analyzer for measuring carbon dioxide and water vapor fluxes, three-dimensional sonic anemometer for determining wind speed in three dimensions, and biomet (biological & meteorological) sensors to collect ancillary data for filling measurement gaps and interpreting flux results. Installation and preliminary field tests of the EC systems have been completed. The systems are being used to collect data for research on water management technologies and climate change impact on agroecosystems in the Mississippi Delta.<br /><br /><a href="/conference/pdf/sui_ruixiu2016.pdf">Download the presentation</a>
Towards an Improved Understanding of On-Farm Water Storage Systems in Mississippi: How Much Water Is Lost from These Systems?
Year: Authors: Perez-Gutierrez J.D., Paz J.O., Love M. Tagert M.
On-farm Water Storage (OFWS) systems can mitigate downstream nutrient-enrichment pollution originating from agricultural landscapes. In the Mississippi Delta, an OFWS system usually combines tail-water recovery (TWR) ditches and on-farm reservoirs. The surface runoff and irrigation tail water is collected by ditches, and most of this water is pumped to reservoirs to be stored for future irrigation needs. The remainder of the in-ditch water evaporates, infiltrates, or flows out of the system. Previous studies have focused their attention on the spatial and temporal water quality changes throughout OFWS systems to quantify their nutrient reduction capacity. However, less attention has been placed on measuring the volume of water that is effectively lost from these systems, which is important to investigate so we can better understand the net environmental benefits of using OFWS systems. This study presents preliminary results of water quantity monitoring at the outlet pipe of an OFWS system implemented on a farm located in Porter Bayou Watershed, Mississippi. This data obtained from this study will help to better quantify and provide additional insight on the benefits of OFWS for nutrient reduction and water storage in agricultural watersheds.
Assessment of tailwater recovery system and on-farm storage reservoir water and nutrient harvesting
Year: Authors: Omer A.R.
The Lower Mississippi Alluvial Valley is economically important due to its highly productive agricultural land. However, producers in this region face two predominant environmental issues that are inherently linked to the intensity of the agricultural industry in this region. First, intensive agriculture practices have resulted in increased surface transport of nutrient-laden sediments, contributing to eutrophication in receiving waters and to the Gulf of Mexico Hypoxic Zone. Second, current water withdrawals from the Mississippi Alluvial Aquifer for irrigation are not sustainable. These issues threatening environmental resources necessitate use of best management practices and groundwater conservation. This research investigates systems of best management practices as water resource conservation methods. Such practices include surface water capture and irrigation reuse systems. Referred to as tailwater recovery systems (TWR), this practice consists of a tailwater recovery ditch which may be paired with on-farm storage reservoirs (OFS). Seven case studies of different TWR were monitored for nutrients during the 2014 and 2015 growing season at: inflow, edge of field, TWR, OFS, and overflow locations. Investigations highlight functionality for nutrient recycling, and descriptions of nutrient loss mitigation. Preliminary results for seven TWR in 2014 and 2015 show a mean of 94.05 mega liters of water being recycled applying a mean of 0.86 kg/ha total nitrogen and 0.2 kg/ha total phosphorus back onto the tillable landscape. These systems are proving successful in holding water on the landscape, recycling that water, and therefore nutrients; thereby preventing those nutrients from being lost to downstream waters. This suggests that TWR, or systems with similar water holding capacity, have potential for water resource conservation in the Lower Mississippi Alluvial Valley.
MDEQ's Mississippi Comprehensive Ecosystem Restoration Tool
Year: Authors: Strange T.
As a result of the Deepwater Horizon Oil Spill (DWH), Mississippi is working to restore the health and ensure sustainability of the coastal landscape affected by the spill. To ensure sustainable restoration is achieved, the National Fish and Wildlife Foundation (NFWF) Gulf Environmental Benefit Fund (GEBF) agreed that an ecosystem restoration plan was needed in Mississippi. They approved to fund the development of the Mississippi Restoration Plan. One of primary goals of the Plan is to develop the Mississippi Comprehensive Ecosystem Restoration Tool (MCERT), which is a science-based tool for identifying and examining ecological resources and stressors at a landscape/seascape scale and that allows for improved restoration planning and informed decision making. MCERT represents a suite of geospatial analysis models that provide data products to describe the terrestrial landscape and the marine and water quality conditions in south Mississippi. Two of the MCERT components deal directly with water quality and watershed characterization. The water quality model integrates the Soil and Water Assessment Tool (SWAT). We calculated a 2006-2013 simulation of water, sediment, and nutrient flow in the Pearl, Pascagoula, and Mississippi Coastal basins, as well as indices of change between these and the outputs from an earlier 1987-1994 simulation of the same area to highlight broad indicators of water quality change within the study area using three primary parameters: sediment, nitrogen, and phosphorus at the subwatershed and stream reach level. Stream gauge data from the USGS and observed sediment and nutrient loading data points from the MDEQ are used to calibrate the model to better reflect field conditions. The watershed characterization component of the tool uses derived spatial data, including environmental resource and stressor/threat data, as inputs and aggregates the information to characterize subwatersheds by quantifying the amount, weighting, scoring, and normalizing of the input data. Within each subwatershed, various datasets are assigned values and are adjusted, normalized, and ranked relative to one another. Data inputs include but are not limited to SWAT outputs, dam storage ratios, protected areas, T & E species presence, ecological hubs and corridors, and a landscape development index (LDI). The Mississippi Restoration Team uses these tools to identify hotspots and areas of interest as well as simulate best management practices to quantify restoration scenarios across the landscape. Manipulation of climatic, hydrologic, and land use inputs offers further potential for modeling future scenarios, incorporating both agricultural and non-agricultural management practices, at various spatial and temporal scales.
Evaluation of Crop Rotation and BMPs on Water Quality and Quantity using SWAT
Year: Authors: Ni X.
Corn after soybean is a common crop rotation practices in the Mississippi Delta. Several Best Management Practices are also implemented in the Big Sunflower River Watershed (BSRW). Placement of BMPs and crop rotation practices will affect water quality and quantity in the BSRW. This study will simulate the impacts of different placements of BMPs and corn after soybean rotation in the BSRW using SWAT model. Soil and Water Assessment Tool (SWAT) model was calibrated at Harris Bayou, validated at Bogue Phalia and verified at BSRW using 17 years of stream flow, sediment and nutrient data. Model performances during calibration, validation and verification were ranged from 0.61 to 0.63 for R2, 0.46 to 0.62 for NSE. Results of different crop rotation practices and their effects on water quality and quantity will be evaluated and presented in the conference.
Natchez Trace Ecological Forecasting and Water Resources: Utilizing NASA Earth Observations to Assess Current and Historic Wetland Extent along the Na
Year: Authors: Lynn T.
This project partnered with the National Park Service (NPS) to produce needed land cover mapping products for the Natchez Trace Parkway and to address community concerns involving the past, current, and future wetland conditions of this area. The parkway occurs in Mississippi, Alabama, and Tennessee. Beavers have altered current and historic wetland conditions in the study area by changing streamflow along adjacent rivers and tributaries. While the ecological services provided by these beavers can benefit wetland ecosystems, indiscriminate and excessive dam building has caused issues with flooding, property damage, and road maintenance within the parkway. NASA Earth observations (Landsat 5 Thematic Mapper, 7 Enhanced Thematic Mapper Plus, and 8 Operational Land Imager) and ERDAS IMAGINE were used to generate a time series of land use/land cover (LULC) classification maps from October 1992 to January 2015 showing wetland status occurring along the parkway. A projected LULC classification map was also produced using TerrSet Land Change Modeler software. This LULC time series and modeled projection will aid the NPS in wetland conservation and beaver management plans throughout the Natchez Trace Parkway.
Data-collection efforts by the U.S. Geological Survey during the winter flood of 2015 on the Lower Mississippi River
Year: Authors: Manning M.A.
In December 2015, the National Weather Service (NWS) began to predict and warn communities in flood prone areas that the Mississippi River would reach record flood levels in many areas. Based on these predictions, the U.S. Geological Survey (USGS) began to deploy flood-measuring crews at many locations on the Mississippi River to confirm and document these higher streamflow's. As flood waters moved southward along the main stem of the Mississippi River, several USGS teams from offices within the Lower Mississippi-Gulf Water Science Center measured streamflow at several locations in the Lower Mississippi River system. In addition to the USGS, other agencies involved with streamflow measurements and flood forecasting in the Lower Mississippi main stem reaches included the NWS, as well as, the U.S. Army Corps of Engineers - St Louis, MO, Memphis, TN, Vicksburg, MS, and New Orleans, LA, districts. By mid- to late-January 2016, approximately 72 non-routine streamflow measurements were made at various locations in the Mississippi River main stem system. These measurements were used to confirm stage-discharge ratings and support NWS flood-forecast models as the crest moved into the lowermost reaches of the Mississippi River basin near New Orleans, LA. These streamflow data, in combination with other hydrologic measurements, are widely used by local, State, and Federal agencies to predict flood-inundated areas, as well as, to maintain and operate flood-control structures that are used to divert or reduce major flooding near New Orleans, LA. In addition to numerous flow measurements, several USGS crews collected flow-weighted water-quality samples and maintained continuous water-quality monitors that measured water temperature, salinity, pH, dissolved oxygen, nitrate, and turbidity, to characterize changes in water quality due to increased flow. The Tennessee Department of Environmental Conservation (TDEC) assisted the USGS with water-quality-data collection at Memphis, TN. In mid-January, near peak streamflow on the Mississippi River at Vicksburg, MS, a group of USGS scientists from more than 9 offices throughout the Nation, collaborated to collect extensive streamflow, bathymetry, water velocity, and bedform data at that site to help advance new research regarding the use of remotely-sensed data collected from onsite video, Predator drone recordings, and satellite imagery to compute streamflow. This research effort will help expand the understanding of flood dynamics, as well as, potentially reducing the physical manpower required to measure flood events in the field.<br /><br /><a href="/conference/pdf/manning_mike2016.pdf">Download presentation</a>
A demonstration Project: Measurement of Sediment Oxygen Demand and Nutrient Fluxes in on Eckie's Pond, MS
Year: Authors: Laurens L., Ortega S.L., Martin J.L., Ramirez-Avila J., Martin J.L.
One of the processes long known to impact the water quality of surface waters is the oxygen demand by, and nutrient release from, sediments. Sediment oxygen demand (SOD) and nutrient releases, due to the mineralization (diagenesis) of organic materials in bottom sediments, can contribute to eutrophication, harmful algal oxygen blooms and hypoxia. SOD and nutrient releases are commonly measured using one of two alternative techniques: by in- situ deployment of chambers on the bottom of the water body; or, by the collection of sediment core samples which are transported to the laboratory where SOD and nutrient fluxes are measured under controlled conditions. The main objective of this study was to develop the capability of using the core method, based on methodologies developed by the Horn Point Laboratory at University of Maryland and extensively used in Chesapeake Bay, and to compare results to chamber measurements at a selected site on campus at Mississippi State University, Eckie's pond. Other goals included the development of standard operating procedures (SOP's) for all the processes and the completion of a laboratory setup. The developed methodology could then be applied to other selected Mississippi water bodies to provide flux measurements in support of related oxygen and nutrient management studies. Overall research goal considers long term measurements of sediment fluxes, sediment diagenesis, and water column concentrations in order to evaluate factors influencing sediment diagenesis, to support evaluation and development of diagenesis models such as that included in the USEPA Water Analysis Simulation Program.
Refining Designated Uses For Mississippi's Surface Waters
Year: Authors: Caviness-Reardon K.
Water quality standards are required by the Clean Water Act and include three essential components: (1) designated uses for the water bodies, (2) criteria (either narrative or numeric) to support those uses, and (3) an antidegradation policy. Water quality standards establish the water quality goals for a water body. Designated uses are a critical component of water quality standards because they specify what a specific water body is being used for in order to define the appropriate water quality goals provide a way to evaluate whether or not these goals are being attained. Mississippi currently has a very simple water body classification structure. Within recent years, the Mississippi Department of Environmental Quality (MDEQ) has identified the need to examine the current water body classification structure and investigate further refinement of the existing water body classification structure. In 2014, MDEQ completed a preliminary analysis to consider potential options for refinement of the current structure. Further refinement of water use classifications will allow MDEQ to provide a more accurate distinction between water bodies around the state and allow for more appropriate criteria (or goals) to be established for those various water bodies. . Water use classification (or designated use) is the basic foundation of the water quality standards program, and improving the accuracy of water body classifications within Mississippi is a program priority for MDEQ's Water Quality Standards Program.
Agricultural Chemical Monitoring Program Overview
Year: Authors: Billiot J.
Agriculture is Mississippi's number one industry. A wide variety of agricultural compounds are used to support this industry. Since over ninety percent of the population of Mississippi relies on groundwater for drinking water, there has been concern that the groundwater resources of Mississippi may be impacted and degraded by the use of pesticides and herbicides. In an effort to better determine the impact of agricultural chemicals on groundwater resources, the Agricultural Chemical (AgChem) Groundwater Monitoring Program was designed in 1986 and implemented in March of 1989. Since the inception of the program, over 2,100 samples have been taken from wells around the state and analyzed for more than 100 herbicides and pesticides. Of the samples collected to date, 96.6% have no detectable concentrations of agricultural chemicals present. Of these samples with detects, only four were found to have concentrations exceeding the maximum contaminant levels (MCLs) set by the United States Environmental Protection Agency (EPA). Results indicate that Mississippi's groundwater quality is relatively unaffected by agricultural activities.
Source Water Assessment Program
Year: Authors: Warner J.
The 1996 amendments to the Safe Drinking Water Act mandated states to develop and implement a Source Water Assessment Program (SWAP). The purpose of this program was to notify Public Water Systems (PWS) and customers regarding the relative susceptibility of their drinking-water supplies to contamination. Congress intended for these susceptibility assessments to encourage efforts that would enhance the protection of PWSs by managing identified potential contaminant sources of concern. In 1998, the Mississippi State Department of Health (MSDH) contracted with MDEQ to develop and administer the SWAP in Mississippi. OLWR's Source Water Assessment Program was designed to identify and properly manage potential contaminant sources in Wellhead Protection Areas from which PWS wells capture their water over a specific period of time. OLWR staff ran countless computer simulations and undertook an extensive data review of Mississippi primary drinking water aquifers in order to come up with meaningful Wellhead Protection Areas and a ranking system was implemented in order to inform PWSs of their relative susceptibility. <br /><br /> Assessments of all public groundwater systems and three of the five public surface water systems operating in the state have been completed. The SWAP reports and corresponding maps of delineated Source Water Protection Areas are available online at the MDEQ website: http://landandwater.deq.ms.gov/swap. OLWR now requires that preliminary assessments of proposed public water supply wells site be performed by MDEQ prior to the issuance of groundwater withdrawal permits. These preliminary assessments allow the suitability of proposed well sites to be screened prior to the drilling and completion of PWS wells. The OLWR staff continues its efforts to protect the drinking water supplies of the 1,200 public water systems operating in the state as part of activities related to the Source Water Assessment/Protection Program. MDEQ is working closely with the Mississippi State Department of Health's Water Supply Division to assist in the implementation of the EPA's Groundwater Rule.<br /><br /><a href="/conference/pdf/warner_john2016.pdf">Download presentation</a>
Developing Numeric Nutrient Criteria For Mississippi's Surface Waters
Year: Authors: Young A.
Over the last 50 years, the amount of nitrogen and phosphorus entering our surface waters across the nation has increased significantly. The degradation of water quality associated with excess levels of nitrogen and phosphorus in our surface waters has been extensively studied and documented. In Mississippi, like many other states, excessive amounts of nutrients, including nitrogen and phosphorus, have been a major cause of surface water impairments. In 2001, EPA developed an Action Plan requiring that all states develop numeric nutrient criteria in order to protect our waters from nutrient pollution impacts. Since 2001, the Mississippi Department of Environmental Quality (MDEQ) has been working diligently to develop appropriate and protective numeric nutrient criteria for Mississippi's waters including (1) the development and implementation of MS's Nutrient Criteria Development Plan, (2) collecting extensive data to derive scientifically defensible nutrient criteria, and (3) developing robust tools to assess the biological condition of our waters. In 2010, MDEQ formed the MS Nutrient Technical Advisory Group (TAG) consisting of members of state, federal, and research scientists to aid the agency in deriving these criteria providing technical knowledge and regional expertise to the criteria development process. In an effort to be more scientifically defensible, MDEQ is applying the multiple lines of evidence approach for nutrient criteria development. The multiple lines of evidence approach involves looking at several lines of analysis, such as distributional analysis, stressor-response, scientific literature, and water quality models to establish a final endpoint. MDEQ is currently working to develop numeric nutrient criteria for the various water body types around our state which have been categorized into (1) Non-Delta Lakes and Reservoirs, (2) Coastal and Estuarine Waters, (3) Non-Delta Streams, and (4) Delta Waters. Non-Delta Lakes and Reservoirs will be the first water body type in which numeric nutrient criteria will be established. MDEQ is aiming for a public notice date no later than June 30, 2016. MDEQ will continue with criteria development efforts within the remaining water body types in a sequential manner. MDEQ recognizes the complexities that will be faced when implementing numeric nutrient criteria across the various water programs within MDEQ. Therefore, the agency is has established an internal nutrient criteria implementation work group that is developing a Nutrient Criteria Implementation Plan to describe how the criteria will be incorporated into programs such as permitting, water quality assessment, water quality monitoring, total maximum daily loads (TMDLs), and waste load allocations (WLAs). MDEQ, along with the support of the TAG and the engagement of stakeholders, continues to make great strides in developing nutrient criteria for Mississippi's surface waters.<br /><br /><a href="/conference/pdf/young_alina2016.pdf">Download presentation</a>
Real Time Groundwater Monitoring: Mississippi River Valley Alluvial Aquifer and the underlying Tertiary aquifers of the Mississippi Delta
Year: Authors: Parrish P.C.
This Mississippi Delta in the northwest quarter of Mississippi is largely agricultural. It has long been an Office of Land and Water Resources (OLWR) priority for monitoring and research. This focus comes from the high concentration of wells and water use in this portion of the state. There are approximately 23,430 permitted groundwater wells statewide. The Mississippi Delta has 19,410 of those permits. Due to this high water use, hydrologic factors, and geologic factors, there have been growing concerns about dewatering the aquifer. Groundwater model results indicated the need for more information on the possible exchange of groundwater between the Mississippi River Valley Alluvial Aquifer (MRVA), mainly used for irrigation, and the underlying drinking water Tertiary aquifers in the Mississippi Delta. OLWR began mapping areas where there are possible close proximity of sands between the aquifers. The Delta Drilling Project, initiated between the Office of Geology and OLWR, has provided several locations for sand to sand contact. With this research came the impetus for a Delta-wide monitoring network. The traditional monitoring network of semi-annual survey wells would not be adequate for this type of investigation. Real-time monitoring is an innovative technology that has become more affordable. OLWR needs measurements throughout the year (especially during pumping season) to evaluate any exchange of water between aquifers. Paired well nests were installed in five locations to begin the project. These pairs are located around the center of the regional cone of depression where close proximity sands had been mapped. Instrumentation was installed in one location on October 29, 2015. OLWR has ordered two more sets of instrumentation. The data collected include both water quality and water quantity parameters (water level, conductivity, and temperature). These parameters are sent by cellular transmission in data packets every 15 minutes. The data is housed by McCrometer, which manufactures the instrumentation, and is available through a web portal. OLWR will track fluctuations in the parameters especially during high use periods when heads may drastically differ. This will provide more data on upward recharge and any downward losses to help improve modeling inputs and better manage both drinking water and agricultural water in the Mississippi Delta. OLWR hopes to have at least one well pair in each Delta County and to provide web access for stakeholders in the future.
Harvesting Excess water from the rivers of Little Tallahatchie, Big Sunflower, and the Buffalo.
Year: Authors: Madison J.
Considerable research has been conducted to assess the potential for harvesting rainwater during the off- season in the South, particularly in the State of Alabama (Tyson, T.W., 1999). The correct management strategy for utilization of groundwater and surface runoff is proper allocation of water resources within a catchment. A management strategy utilizing levee embankment ponds for production and rainwater storage has been beneficial in reducing the amount of effluent discharge by as much as 90% and groundwater use by as much as 75% (Cathcart, 1999). Early research (Cathcart et al., 2007) pertaining to rainwater harvesting and storage technologies demonstrated the importance of the implementation of management strategies for conserving groundwater resources. This research will be based upon the utilization of excess floodwaters from Big Sunflower, Little Tallahatchie, and Buffalo rivers using modeling approaches of simulating floodwater capturing methodologies including the use of pumps, siphons, and diversion techniques of streams or rivers along the Mississippi River Basin to augment the water needs for irrigation during the growing seasons (Pote, J., et al. 1988). Additionally, this research will examine 64 years of precipitation data, flood stages, duration of flooding, and will utilize the use of rating curves and back calculations to determine missing data points in the precipitation and flow data records. Data will be obtained from the United States Geological Survey (USGS) and the Army Corps of Engineers (USACE) for the Big Sunflower, Little Tallahatchie, and Buffalo Rivers.
Variable pathways and geochemical history of seepage under the Mississippi River levee: Observations from the 2011, 2015, and 2016 floods
Year: Authors: Davidson G., Voll K., Corcoran M., Kelley J.
During flood stage on the lower Mississippi River, water levels on the river side of a levee can be several meters higher than the surrounding land surface, creating steep hydraulic gradients that drive seepage of water beneath the levees. Sand boils form when sediment is eroded and transported to the surface on the opposite side of a levee, leaving open conduits that can compromise the structural integrity of the levee. The flow path of seepage beneath the levee may be deep or shallow, depending on the surficial geology, with deeper flow pathways found where a levee sits on top of low-permeability channel-fill deposits. For levees over the Mississippi River Valley alluvial aquifer, deeper flow pathways may encounter anoxic water with distinct geochemistry, raising the possibility that flow pathways for individual seeps or sand boils can be elucidated based on their geochemical signatures. Exploratory sampling north of Vicksburg, MS, from the river, from relief wells, and from sand boils during the 2011, 2015, and 2016 flood events shows considerable promise. Relief wells and a small number of sand boils had high iron and arsenic concentrations, consistent with deeper water being driven up to the surface. Most of the sand boils analyzed had iron and arsenic concentrations more similar to river water, consistent with shallow pathways through sandbar deposits. Many sand-boil samples also showed evidence of redox reactions during transit, not just simple mixtures of river water and groundwater. In select relief wells and sand boils, sampling was repeated after three weeks of continuous flow (2015), and again during a subsequent flood (2016), to identify short term geochemical and isotopic changes that may occur as flood waters move increasingly into the subsurface. Preliminary results show significant changes in tritium concentration over time.<br /><br /><a href="/conference/pdf/voll_kaitlin2016.pdf">Download presentation</a>
Prediction of Future Agricultural Water Needs in Mississippi Delta and Blackland Prairie under Surface Water Supply and Groundwater Pumping Scenarios
Year: Authors: Feng G., Ouyang Y., Reginelli D., Jenkins J.
The total area of Mississippi is approximately 30 million acre, grain crops take 4.6 million acre lands. Mississippi western Delta (5 million acre in total) and eastern Blackland Prairie (total 3 million acre) are two major agricultural regions where 80% of the MS croplands are planted. The Delta region accounts for 67% of the state croplands, over 90% of irrigation water is pumped from groundwater. The ongoing irrigation depletion of groundwater which has already declined to the alarming level in the Delta threaten agricultural productivity and sustainability. Enhancement of surface water supply is the solution to reduction of groundwater usage in the state which is rich with rainfall and surface. Sustainable conjunctive use of surface and ground water resources for irrigation requires knowledge of crop water requirement and deficit as well as prediction of future agricultural water needs. Soybean, corn and cotton are planted on 65% of croplands in Mississippi. Therefore, irrigation water needs of the three dominant crops were predicted. Patterns and trends of rainfall, reference evapotranspiration (ETo), water deficit and irrigation requirement in Delta (1915-2015) and Blackland Prairie (1894-2014) were analyzed using time series statistical models for annual, seasonal, and monthly periods. An AutoRegressive, Integrated, and Moving Average (ARIMA) approach was used to develop monthly and annual models for rainfall and ETo prediction. The ARIMA models forecasted 1319 mm of mean annual rainfall and 1203 mm of mean annual ETo in the two regions from 2016 to 2024. Those models predicted that soybean, corn and cotton need irrigation of 7.1, 6.6 and 6.9 inch yr-1. In 2014, there are 283,535 and 31,654 ac of cotton, 382,935 and 71,428 ac of corn, 1,595,363 and 217,640 ac of soybean in the Delta and Blackland Prairie, respectively. Totally, the three major row crops need 1.3 million acre feet of water in Delta and 0.2 million acre feet in the Blackland Prairie for irrigation each year. Surface water as an alternative option must be taken to place irrigation agriculture on a sustainable path. Our STELLA pond hydrological process model predicted that the ratio of pond size to irrigated crop land is 1:18. There are approximately 251,983 and 77,186 acre of surface water in the Delta and Blackland Prairie. If 19% and 16% of those surface water is used for irrigation in the two regions, at least 37% (481,155 acre feet) and 100% (185,837 acre feet) of groundwater could be saved in the MS Delta and Blackland Prairie, respectively.<br /><br /><a href="/conference/pdf/feng_gary2016.pdf">Download presentation</a>
Water Quality in Bangs Lake: effects of recurrent phosphate spills to a coastal estuary: Year 2
Year: Authors: Dillon K., Caffrey J., Carmichael R.H., Cressman K., Woodrey M.
Grand Bay National Estuarine Research Reserve (GBNERR) is located in a relatively pristine estuary in the northern Gulf of Mexico, with ambient nutrient concentrations often below detection. However, since 2005, periodic breaches in a containment levee from a phospho-gypsum stack have led to high phosphate levels (over 200 µM) while pH dropped from 7.5 to near 4.5. GBNERR staff assembled a phosphate working group to investigate scientific questions related to these phosphate loadings. This working group includes members from GBNERR, regional universities, marine labs, and Mississippi Department of Environmental Quality. They identified four essential questions needed to assess the impacts of repeated phosphate spills on water quality in an otherwise pristine ecosystem. (1) What is the fate of phosphorus after a spill? (2) Is there a preserved sedimentary record of past phosphorus spills? (3) Is there a biological fertilizer effect on benthic microalgae in this shallow photic system? (4) Is dry deposition of gypsum particles from the adjacent fertilizer plant a smaller but constant source of phosphorus to GBNERR? Research results will provide information critical for management of the Reserve.
A preliminary investigation of surface and groundwater exchange within tailwater recovery systems in the Mississippi Delta
Year: Authors: Baker B.H., Prince Czarnecki J.M., Barlow J.R., Dibble E., Omer A.R., Rogers J.
Substantial withdrawals from the Mississippi Alluvial Aquifer for irrigation have resulted in a long-term trend of decreasing groundwater levels. Agricultural producers are adopting tailwater recovery systems, a best management practice for capturing surface water for re-use, but scientific data is lacking on the ability of these systems to mitigate aquifer depletion. One current area of interest is the potential for these systems to serve as a recharge mechanism. It is proposed that instrumenting tailwater recovery systems of varying age with piezometers, equipped with multiple loggers that measure temperature, atmospheric pressure, and depth, will provide data for a groundwater flow and heat transport model developed using VS2DH. Quantification of ground and surface water exchange indicated that over the observation period some influence from surface water was likely being exerted on groundwater stores. However, gradual changes in well temperature indicate low hydraulic flow rates between compartments. Additionally, gradual temperature changes were observed to change at a greater rate in the new (<1 year old) tailwater recovery system, indicating that age of the system does impact groundwater - surface water interaction. Surface water quality analysis resulted in low nutrient concentrations. Low flow rates and nutrient concentrations result in minimal concern for groundwater leaching from TWR/OFS systems.
Spatial and temporal trends for mercury concentrations in fish from three north Mississippi lakes and human health risk assessment
Year: Authors: Willett K.L., Cizdziel J.V., Meals K., Brewer S., Thornton C.
Total mercury (Hg) concentrations were determined in the skeletal muscle of 310 fish collected during 2013 and 2014 from three northern Mississippi lakes (Sardis, Enid and Grenada) that are extensively used for fishing and recreation. Largemouth Bass (LMB), Channel Catfish (CC), White Crappie (WC), and Gizzard Shad (GS), that represent a range of trophic levels, were studied. Creel data indicated anglers harvested 372,711 kg of WC, 26,735 kg of CC, and 14,871 kg of LMB, the three most targeted species of fish, from the lakes. Median Hg concentrations (ng/g) were highest in LMB (443, n=64), followed by CC (211, n=72), WC (192, n=101), and GS (49, n=73). Fish-Hg concentrations were lower than those reported in fish >10 years ago, but there were significant differences between lakes consistent across species. Grenada fish-Hg concentrations were higher than those from Enid and Sardis. Because existing consumption advisories for CC are length-based, the lack of a significant relationship between length and Hg concentration indicated that the recommendations may not be protective enough. Furthermore, five different risk assessment paradigms yielded hazard quotient values suggesting that existing fish consumption advisories may be insufficient to protect adults, and especially children, from exposure to Hg.
Exoenzyme activity and algal biomass responses to experimental nutrient gradients identify factors driving nutrient limitation of algal biomass in an
Year: Authors: Taylor J.M., Jenkins M., Lizotte R., Locke M., Dillard K., McChesney D., Testa III S., Bryant C.
The development of robust algal biomass-nutrient enrichment relationships for lakes within the Mississippi Delta is challenging due to a lack of undisturbed conditions. However, examining long-term water quality datasets linked to best management practices, combined with nutrient enrichment experiments may provide insight into factors that limit algal biomass. We examined seasonal patterns in nutrients, sediments and chlorophyll α (chl. α) over several years in Beasley Lake. Implementation of conservation practices within the watershed resulted in significant reductions in sediments and nutrients, particularly phosphorus (P), within the lake. However, chl. α concentrations continue to remain higher than recommended criteria during the growing season despite reductions in lake P concentrations. Seasonal patterns in activity of exo-enzymes associated with mineralization of nitrogen (N) and P suggest that nutrient demand is greatest at the end of the growing season when algal biomass is high and nutrient inputs are low. Experimental algal bioassays indicated that both chl. α and FDA (a measure of overall microbial activity) increased according to Michaelis-Menten dynamics with increasing dissolved N and P. We only observed maximum chl. α below recommended 20 µg/L concentrations when dissolved inorganic N (DIN = NH<sub>4</sub>-N + NO<sub>2</sub>-N + NO<sub>3</sub>-N) concentrations were below 0.2 mg/L despite high soluble reactive P (SRP) of 0.345 mg/L. In contrast, chl. α concentrations were always higher than the management target when DIN was not limiting (1.6 mg/L) despite very low SRP concentrations (0.015 mg/L) which suggests that N may be the primary limiting nutrient in Delta oxbows. Acid Phosphatase Activity (APA), an exoenzyme associated with mineralization of P, decreased with SRP and increased with DIN enrichment suggesting that P demand was related to availability and N:P ratios. In contrast, NAG and LAP, two exoenzymes associated with mineralization of N, increased rather than decreased with DIN enrichment and were correlated with chl. α. Chlorophyll α and FDA peaked at N:P ratios of 16:1 indicating that optimal elemental ratios for eutrophic oxbow lakes are similar to those observed in marine environments and some freshwater lakes. From a water resource management and monitoring perspective, our results suggest that exoenzyme activities may provide additional insight into complex relationships between nutrients and algal biomass in oxbow lakes. Furthermore, management practices that reduce N inputs to agricultural water bodies may be key to reducing chl. α concentrations below recommended goals for maintaining ecological integrity of Mississippi Delta oxbow lakes.es.<br /><br /><a href="/conference/pdf/taylor_jason2016.pdf">Download the presentation</a>
Ecological Significance of Phyllosphere Leaf Traits on Throughfall Hydrology, Biogeochemistry and Leaf Litter among Quercus Species in the Southeaster
Year: Authors: Limpert K., Siegert C.M., Karunarathna A.A.
Quercus (oak) is a dominant species in many forest ecosystems across the United States that contribute vital ecosystem services through water and nutrient cycling. The recent decline of Quercus, largely due to fire suppression and forest mesophication, has the potential to alter forest hydrological and biogeochemical cycling. Given the prevalence, persistence, and diversity of Quercus leaves in forest ecosystems, it is likely that this species strongly mediate nutrient cycling when present. The objective of this study was to (1) quantify canopy-derived nutrients contributed to forest ecosystems and (2) determine interspecific temporal distribution of Quercus leaf fall in an oak-hickory forest in Mississippi. Beginning in Fall 2014, throughfall quantity and chemistry were measured during individual storm events under each of the four focal Quercus species and two non-Quercus (Carya) species and canopy litterfall was collected weekly to quantify changes in canopy leaf area index (LAI) and timing of species-specific leaf fall rates, and determine Throughfall depths decreased as leaves were lost but were greatest in Quercus species compared to Carya and were highest in Q. shumardii, and Q. stellata. The average total kjeldahl nitrogen (TKN) content of throughfall was highest in Q. shumardii (1.44 mgL-1) and Q. stellata (1.65 mg L-1) compared to other Quercus and non-Quercus species. Q. stellata had the greatest total organic carbon (TOC) for the majority of rain events with the largest amount reaching 119.43 mg/L-1. Quercus species contributed larger amounts of essential anions (Cl-1, NO3-, SO4-2). During the winter of 2014-2015, Q. shumardii had the highest leaf retention although non-oak species had a higher leaf retention in general. Leaf fall varied during the winter of 2015-2016 with Q. alba species having longer leaf retention compared to other Quercus and Carya species. Quercus shumardii had the lowest average C:N amounts (43.99 mg L-1) in leaf litter content compared to the other Quercus species. Non-oak species had a considerably lower average C:N ratio (Carya spp. 32.58 mg L-1).
Developing a Habitat Suitability Model for Oyster Restoration in St. Louis Bay
Year: Authors: Adenihun J., Linhoss A.C., Camacho R.A.
Oyster formations in the Northern Gulf of Mexico are declining rapidly due to over-harvesting, pollution, and changes in hydrology. Oysters depend on a number of environmental factors including water depth, the availability of hard substrate, salinity, temperature, dissolved oxygen, and PH. Oyster reefs provide important ecosystem services including fish habitat, water filtration, storm protection, sequestering carbon, providing food security, forming an economic industry, and as a cultural symbol. Oyster reef restoration can add value to the U.S economy with a sack of oysters fetching up to $40 at market. The objective of this research is to use a hydrodynamic model coupled with a water quality model to simulate conditions that are important for oyster reefs along the Gulf Coast of Mississippi. We will use the existing Environmental Fluid Dynamics Code (EFDC) and Water Quality Analysis Simulation (WASP) models that have been developed for Bay St. Louis, Mississippi. EFDC simulates water quality parameters that are required to run the WASP model, such as velocity, flow rate, temperature, diffusion, dispersion, and salinity. Meanwhile, WASP model generates parameters that are important for the growth of oyster reefs in the Northern Gulf of Mexico, such as dissolved oxygen, phosphorus, nitrate, nitrite, phosphorus, and total suspended solids. We will develop a habitat suitability model for oysters based on the exiting mapped locations of oyster reefs along with environmental parameters that are important for oyster growth and survival.
Multidisciplinary Remediation: An Analysis of Chlorinated Metabolites in Groundwater Contaminated by Pentachlorophenol Following 15 Years of Air/Biosp
Year: Authors: Stratton J.N., Stokes C.E.
Pentachlorophenol (PCP, Penta) got its foothold as a wood preservative in the United States because it extends the lifetime of wood products up to 40 years, even in adverse conditions. It is also an effective herbicide and biocide. Because of this effective nature against pests, it was applied as a protectant in many areas of agriculture and manufacturing. The site utilized in this study has been a receiver of penta wastewater from a wood product treating facility. To comply with mandated cleanup, injection wells for air injection were installed in 2000. These were used until 2011, when they upgraded the airsparging system and included enhanced biosparging. Shortly after this, 400 hybrid poplar and cottonwood trees were planted in the area for an added aspect of phytoremediation. The latest remediation protocol for the site utilizes in-situ chemical oxidation (ISCO) with dilute hydrogen peroxide, started in 2015. A set of nine wells were sampled monthly following ISCO treatment. Metabolites were extracted from water samples using a novel modified liquid microextraction protocol, followed by analysis on an Agilent GC 6890 to determine the presence of chlorinated compounds resulting from the degradation of penta (ongoing through April 2016). We expect to determine the concentration of chlorinated metabolites, analyze the spatial distribution of these compounds across the site, and make recommendations as to the future of remediation treatments for this location.
Using deuterium and oxygen-18 stable isotopes to understand mechanisms of stemflow generation as a function of tree species and climate
Year: Authors: Siegle-Gaither M., Siegert C., Keim R.
Stemflow (SF) is a type of rain partitioning from the forest canopy that redirects intercepted water down tree trunks. Through this mechanism, SF leaches nutrients from the canopy and bark to deliver highly enriched water to the base of the tree. Few studies have examined the species-specific effects of bark structure and storm meteorological conditions on SF generation by means of stable hydrogen ( δD) and oxygen δ<sup>18</sup>O) isotopic tracers. This study explores these relationships in an oak-hickory stand and a pine plantation in central Mississippi. The species selected for this project have unique bark characteristics and variable effects on rainfall partitioning centered on their geographic distribution. Specifically, SF volume and isotopic composition are measured over a one-year period. The objectives of this study are (i) to determine origins and pathways of stemflow water using stable water isotopes, (ii) to identify differences in stemflow generation mechanisms between tree species, and (iii) to identify differences in stemflow generation mechanisms between storm events. <br /><br /> Stemflow collars were installed on seven species of trees with three trees per species. Water samples were collected within 12-24 hours after individual storm events. Tree characteristics such as species, height, and bark thickness were measured. Laser ablation spectroscopy was used to analyze δD ad δ<sup>18</sup>O in the water samples collected. Preliminary results show that bark thickness was greatest in <em>Pinus taeda</em> (1.74 ±0.09cm), followed by <em>Quercus alba</em> (1.56 ±0.08cm), <em>Q. stellata</em> (1.19 ±0.13cm), <em>Q. shumardii</em> (0.95 ±0.08cm), <em>Q. pagoda</em> (0.95 ±0.05cm), <em>Carya glabra</em> (0.83 ±0.09cm), and <em>C. ovata</em> (0.56 ±0.10cm) (n=24 for all species except <em>P. taeda</em> where n=40). Additional preliminary results suggest that the isotopic composition of stemflow is distinct from that of throughfall and bulk precipitation. A better understanding of isotopic composition (δD and δ<sup>18</sup>O) and stemflow generation mechanisms will allow for more accurate hydrological and biogeochemical models to be established.
Towards an understanding of surface and groundwater exchange through tailwater recovery system
Year: Authors: Rogers J., Baker B., Czarnecki J.
A long-term trend of depletion of groundwater levels are the result of significant withdrawals from the Mississippi Alluvial Aquifer for irrigation purposes. Tailwater recovery systems, a best management practice to re-use surface water for irrigation purposes, are being implemented by many agricultural producers throughout the Mississippi Alluvial Valley, however, there is very little scientific evidence that proves these systems have the ability to reduce aquifer depletion. To investigate surface-groundwater interactions in these systems, steel piezometers equipped with multiple loggers that measure temperature, atmospheric pressure, and depth were installed in two tailwater recovery systems.It's anticipated that the collection of this data will be appropriate to develop a ground and surface water flow and heat transport mode using VS2DH resulting in the current area of interest that these systems potentially serve as a recharge mechanism. The magnification of ground and surface water exchange could provide the additional data for those estimating Aquifer levels, as well as, assist policymakers in implementing techniques to appropriately manage this critical resource. In addition, the collection of surface and groundwater samples was endeavored to determine any water quality impacts resulting from ground and surface water exchange.
Utilizing My Maps Feature in Google Maps as a Multipurpose Watershed Planning Tool for the Escatawpa River
Year: Authors: Liao J., Pote J., Wax C., Linhoss A.
This project involved using a tool to coordinate and track activities impacting an entire watershed and producing a synoptic map giving a snapshot in time. This allows multiuser analysis and discussion for setting priorities in future development. The Escatawpa River was selected to demonstrate this capability. Issues addressed were both water quality and water quantity. It has become growingly important to address the accumulation of activities in the entire watershed. For example, in terms of water quality, elevated bacterial counts can impact oyster harvest. In terms of water quantity, decreased flow raises salinity levels impacting the estuarine and coastal ecosystem of the Mississippi Sound. This project mapped activities along the length of the Escatawpa River and its tributaries that might explain variations in water quality and quantity of the river. The method chosen for this multipurpose study was My Maps feature in Google maps. My Maps is an interactive tool that allows users to position markers and leave annotations. The markers have different colors and shapes to help the user stay organized. Furthermore, the users can go back and forth between different types of maps such as satellite and terrain. In this study, several categories were examined which included tributaries, impact analysis, gage stations, golf courses, and septic systems. The categories are differentiated based on color, and the subcategories are separated based on shape. Each marker is assigned its respective color and shape. Furthermore, each marker has a description section to record observations and to keep track of discoveries. These information could be used to prioritize targeted areas of concern and accumulated effects of activities. Discrepancy between terrain and satellite maps were of particular interest, since they could reflect either a flaw in mapping or a change over time. Usually, the discrepancy revolved around bodies of water missing or existing in one type of map and not in the other.
An Examining of the Changes in the Hydrological Environment around a Surface Lignite Coal Mine over the Last 20 Years
Year: Authors: Foote J.
The population and industrial complexes of Choctaw County utilizes much of its water from an aquifer system in the Tertiary age Wilcox unit of the Mississippi Embayment. Utilizing 20 years of surface and ground water physical chemistry (P-Chem) analysis, potentiometric groundwater records of Choctaw County public water wells as well as industrial P-Chem analysis and surface and ground water level records from an industrial complex, this study examined the changes to the hydrosphere that has taken place since 1995. Analysis of the hydrosphere shows that over the last 20 years, there has been a drop in the potentiometric surface of Mississippi section of the Lower Wilcox Aquifer system. The analysis also shows changes in the surface water physical chemistry of the hydrosphere. These changes include a decrease in the concentration of free CO2 and chloride, and fluctuations of Alkalinity. Comparisons between groundwater records taken from the industrial complex and other locations around Choctaw County, show little variation in the physical chemistry.
Crop water requirement, rainfall deficit and irrigation demand of major row crops in Mississippi Delta
Year: Authors: Tang Q., Feng G., Ouyang Y., Jenkins J.
The Mississippi Delta is the most productive region in the state where 67% of the state croplands is located. Because irrigation can stabilize and increase crop yield and profit, irrigated acreage is rapidly increasing. Currently, irrigated croplands are not over 30% of its croplands yet, which already consumed groundwater down to the alarming level due to lack of knowledge regarding rainfall deficit and crop water requirement in the region. Objective of this study was to determine rain water deficit, crop water requirement and irrigation demand for improving irrigation management of crops grown in the MS Delta. We developed a STELLA soil water balance model and utilized weather records at Stoneville station for 100-years period, 1915 to 2015. The analysis showed average annual rainfall was 1290 mm with a mean annual reference evapotranspiration (ETo) value of 1202 mm. Most rainfall occurred off-growing season in January to April, November and December, their mean monthly rainfall was 124, 123, 130, 134, 120, and 133 mm, while less rain was received in August (66 mm), September (80 mm), October (81 mm), May (81 mm), June (90 mm), and July (94 mm). Soybean, corn and cotton were typically planted in early May, late March, and late May, harvested in mid-September, late August, and late October in the MS Delta. Rainfall during the growing season for soybean, corn and cotton was 400, 510, and 435 mm, accounted for 31%, 40% and 34% of annual rainfall over the 100-years period. Early seeding can make crops receive more rainfall, therefore, reduce degree and days of water stress during growing season. Averaged evapotranspiration (ETc) of soybean, corn and cotton was 546, 588, 552 mm. Rainfall is no longer to meet water requirement of soybean, corn and cotton since the 6th, 8th, and 7th weeks after planting, which resulted in rainfall deficit (difference between ETc and rainfall) of 262, 237, and 228 mm, respectively, on average over the last 100 years. As expected, more pan evaporation (E) was measured in May (199 mm), June (213 mm), July (205 mm), and August (189 mm). High linear correlation between monthly E and ETo was found (ETo=0.7829E-0.0468, R2=0.98). Monthly ETo can be estimated in terms of the equation by monthly E values which can be easily measured. Results obtained from the 100 years-long historical time-series data can be applied to improve irrigation scheduling, water resources planning and better design cropping system in the MS Delta.
Potential Solutions for Dealing with High Iron Content in Filter Backwash Water of a Municipal Water Treatment System
Year: Authors: Mealins E., Tagert M.L.
A small drinking water system in central Mississippi uses traditional processes to purify and filter water at their five different water treatment plants. The ground water that the system pumps from the well has a naturally high iron content. When the water goes through the treatment process, the iron flocculates and is eventually captured by large filters. The filters are backwashed regularly, and the backwash discharge is pumped to an onsite basin (an excavated retention pond) in a corner of the property. Currently, the basin is a relatively open system, and it occasionally overfills and spills off of the property. While not harmful to human health at current levels, the area is not aesthetically pleasing during the time the filters are backwashed and shortly thereafter. A design solution for this problem is needed that will effectively keep all of the backwash discharge on site in order to prevent future spillovers. The iron and water may be separated so that the iron can be excavated and used for different potential markets, while the water can be reused for other eco-friendly purposes such as watering the grass on the property. Several potential solution methods are being investigated and will be presented.
Prediction of Bacteria in Recreational Waters Using Artificial Neural Network Modelling
Year: Authors: Douglas C.
Many scientists and government agencies rely on fecal indicator bacteria (FIB) to determine the risk of exposure to pathogens in water. If there is a presence of these indicator bacteria, pathogenic microorganisms may also be present. These bacteria in recreational water bodies pose a health threat to people if ingested during activities such as swimming or from the consumption of marine life. The most commonly tested FIB are total coliforms, fecal coliforms, Escherichia coli, fecal streptococci, and enterococci. The measurement of bacteria can be time consuming (up to 48 hours) and expensive, creating a difficulty in warning the public of a potential risk. Ideally, a predictive model could determine the FIB concentration in real-time, eliminating the current delays. Many analytical, statistical, process-based, and empirical models exist for water quality prediction, but produce a low level of precision. Artificial neural network (ANN) models create a better model for predicting water resource variables because they are often capable of modeling complex systems of behavioral rules or underlying physical processes that are often difficult to simulate. An ANN is a computational model based on the biological neural networks. ANNs consist of processing units known as neurons or nodes that are joined by weighted connections. The connections are adjusted by determining an error quantity between the newly predicted output and the actual output and then applying the correction to each weighted node allowing the network to "learn" as it applies the correction for all data in the model. By modeling the ANN using easily recorded inputs to predict indicator bacteria, the concentration of bacteria can be provided almost instantaneously through the model. Due to the non-linear behaviors of most water quality parameters and the learning capabilities of ANNs, the development of a model could provide an adequate method for determining the risk for pathogen exposure in a timely manner.
Characterization of Surface Water Quality in Sunflower River Watershed, Mississippi
Year: Authors: Ouyang Y., Moran M., Parajuli P., Zhao B.
Characterization of water quality is essential to evaluate river pollution due to natural and/or anthropogenic inputs of point and non-point sources. In this study, surface water quality from three monitoring stations at Big Sunflower River Watershed (BSRW) located in Mississippi during the years from 2013 to 2015 was estimated using the YSI meter and laboratory analysis. Results showed that dissolved oxygen was negatively correlated to water temperature, while total dissolved solid was fairly correlated to water temperature. In general, the concentrations of nitrate-nitrogen (NO<sub>3-</sub>N) and total phosphorus (TP) were highest in spring. Our study further revealed that the minimum, mean, and maximum concentrations in the streams were, respectively, 0.019, 2.31, and 6.43 mg/L for NO<sub>3-</sub>N, 0.01, 0.08, and 0.16 mg/L for TP, and 2.38, 5.81, and 13.29 mg/L for potassium (K).
A new absorbent from chemically modified powder of Bidens pilosa and its characteristics for Cd removal from solutions
Year: Authors: Zhao B., Zhang J., He T., Guan A., Gu N., Ouyang Y.
Bidens pilosa is a harmful invasive plant species in many countries. In this study, a cadmium (Cd) adsorbent for water treatment was developed by modifying the Bidens pilosa powder with chemical agents including hydrochloric acid, hydrogen nitrate, sodium hydroxide, sodium carbonate, sodium bicarbonate and potassium permanganate to test the Cd removal efficiency. Results demonstrated that the modified Bidens pilosa (MBP) powder with potassium permanganate was an effective adsorbent to extract Cd from a solution. To further assess the potential application of the MBP in polluted water, characteristics of the MBP and its related interference ions effect were investigated. Results showed that: 1) the Cd removal efficiency exceeded 97% when the dosage of the MBP was > 1g/L; 2) the Cd removal efficiency remained at about 99% when the initial Cd concentration was < 100 mg/L; 3) the Cd removal efficiency of the MBP was > 95% when the pH ranged from 2.5 to 5.5; 4) more than 90% of Cd in the polluted water was removed by the MBP in 5 minutes and about 100% of Cd was removed after 1 h; 5) the addition of Mg ion had no significant negative effect on Cd removal when the concentration of Mg ion was below 50 mg/L; and 6) the Cd removal efficiency was significantly decreased when the concentration of Zn or Cu ion was 100 mg/L. This study proved that the MBP is an effective absorbent for Cd removal from polluted water. Being a harmful invasive plant, the utilization of the MBP is beneficial to the control of Bidens pilosa. Further study is warranted to investigate the ions competitive effect provided that the MBP is used for wastewater treatment.
Application of a Spreadsheet Model to Groundwater Use in the Yazoo River Basin
Year: Authors: Johnson D.R.
Both the USGS and MS-DEQ have developed intricate groundwater models for the Yazoo Basin in Mississippi. The difficulty in using these models is the amount of time that is required to run the model. A less accurate but faster Excel model was developed to simulate groundwater utilization in the Yazoo Basin. The Excel model can be used to screen many more alternatives than the MERAS model, which then can be applied to the most attractive alternatives. The Excel model was used to explore a range of possible management scenarios to extend the life of the groundwater resources in the Mississippi Delta.
Wastewater management issues of small communities in Jourdan River watershed
Year: Authors: Rainey B., Gude V.G., Truax D., Martin J.
Wastewater treatment and nutrient removal alternatives for large size communities are very well-established and are feasible in many cases. When it comes to the small rural and especially for low-income disadvantaged communities, this is not the case, particularly with regard to nutrient removal. The alternatives for small communities are often viewed as cost-prohibitive and unreliable. While this is partly true, careful selection and implementation of appropriate technologies can result in high performance, energy and cost efficient and environmental-friendly solutions. Assessment of water and wastewater is very crucial to safeguard public health and the environment. However, water quality data on fresh and marine waters in the Mississippi coastal region, especially in Jourdan watershed are still sparse and uncoordinated. Therefore, monitoring these parameters is important for safety assessment of the environment and human public health and the water bodies. We have identified a few small and decentralized communities in the Jourdan River watershed area to assess the current wastewater treatment and management practices and their impacts on the receiving water bodies. This presentation will discuss the preliminary evaluation and understanding on the local water quality issues of the watershed.
Simulation of transient groundwater recharge in deep water-table settings: A simple water-balance/transfer-function model
Year: Authors: O'Reilly A.M.
Deep water-table settings are areas where the water table is below the reach of plant roots and virtually all water that is not lost to surface runoff or evapotranspiration eventually becomes groundwater recharge. To simulate transient recharge in these areas, a simple water-balance/transfer-function (WBTF) model was developed. The WBTF model represents a one-dimensional column from the top of the vegetative canopy to the water table and consists of two components: (1) a water-balance module that simulates the water storage capacity of the vegetative canopy and root zone; and (2) a transfer-function module that simulates the traveltime of water as it percolates from the bottom of the root zone to the water table. Input data requirements include two time series for the period of interest, precipitation (or precipitation minus surface runoff if surface runoff is not negligible) and evapotranspiration, and values for five parameters that represent water storage capacity or soil-drainage characteristics. A limiting assumption of the WBTF model is that the percolation of water below the root zone is a linear process. That is, percolating water is assumed to have the same traveltime characteristics, experiencing the same delay and attenuation, as it moves through the unsaturated zone. This assumption is more accurate if the moisture content, and consequently the unsaturated hydraulic conductivity, below the root zone does not vary substantially with time. Results of the WBTF model were compared to those of the U.S. Geological Survey model VS2DT (a physics-based, variably saturated flow model) and to field-based estimates of recharge. Field-based estimates of daily recharge were computed for a 334-day period by analysis of water-table fluctuations at a site with well drained sand and a water table that ranged from 2 to 3.5 meters below land surface. Recharge was simulated for 1- to 2-year periods for eight hypothetical field sites by using VS2DT and synthesized values of precipitation, evapotranspiration, and soil properties for combinations of two soil types (sand and loamy sand) and four water-table depths (2.5, 5, 10, and 20 meters). The WBTF model reproduced independent estimates of recharge reasonably well for the range of soil types and water-table depths tested: coefficient of determination (r2) was 0.80 and standard error (SE) was 3.2 millimeters per day for the field-based estimates of recharge; and r2 ranged from 0.73 to 0.90 and SE ranged from 0.48 to 1.6 millimeters per day for VS2DT-simulated recharge.
A comparison of five forest interception models using global sensitivity and uncertainty analysis
Year: Authors: Linhoss A.C., Siegert C.M.
Interception by the forest canopy plays a critical role in the hydrologic cycle by removing a significant portion of incoming precipitation from the terrestrial component. While there are a number of existing physical models of forest interception, few studies have summarized or compared these models. The objective of this work is to use global uncertainty and sensitivity analysis to compare five mechanistic interception models including the Rutter, Rutter Sparse, Gash, Sparse Gash, and Liu models. Using a one-hour continuous rainfall simulation and input probability distribution functions of values from the literature, our results show that gross precipitation [PG], the free throughfall coefficient [p], canopy cover [Cc], canopy storage capacity [S], and trunk storage capacity [St] are the most important model inputs. On the other hand, the climatic variables that determine evaporation have relatively low levels of importance in modeling interception based on our rainfall simulation scheme. As such, future modeling efforts should aim to breakdown inputs that are the most influential in determining model outputs into easily measurable physical components. Additionally, low, medium, and high one-hour rainfall scenarios were simulated to determine the sensitivity of input parameters to variable rainfall conditions. Under the low rainfall scenario [PG] was the most important parameter across all five models. Under medium and high rainfall scenarios, parameters that described canopy storage ([S] and [St]) and canopy heterogeneity ([p] and [Cc]) became more important. Because this study compares models, the choices regarding the input probability distribution functions are applied across models, which enables a more definitive ranking of model uncertainty.<br /><br /><a href="/conference/pdf/linhoss_anna2016.pdf">Download presentation</a>
Surface and groundwater modeling in the Platte River watershed to support water resource management
Year: Authors: Woodward D.
COHYST is a cooperative hydrologic study of the Platte River drainage basin in the central part of Nebraska. One objective of COHYST is to develop a comprehensive suite of tools to aid in conjunctively managing surface and groundwater to: 1) maintain the region's extensive irrigation economy; and 2) protect the river habitats used by endangered species. These tools must provide decision-makers with reliable quantitative information about the hydrologic consequences of alternative water management strategies. There also is a need to quantify past hydrologic changes, such as accounting for historic depletions of streamflow.<br /><br /> COHYST 2010 is the second generation of modeling tools within COHYST that involves developing an integrated computer-based model of basin hydrology to be used to calculate the effects of different management scenarios on stream flows and the regional aquifer. Phase I of COHYST 2010 involved design of the modeling work, and development of an observation based water budget for the study area to be used in model calibration. Phase 2 of COHYST 2010 had the objective of building the quantitative tools. Phase 3 is application of the tools to management scenarios and time period updates to the tools.<br /><br /> The Phase 2 tools were completed in 2014 and included a Watershed model, Surface Operations Model, and a MODFLOW groundwater model. We are in Phase 3 of the COHYST 2010 work effort. Models are being updated thru 2010 and the 2014 Model documentation is being edited to include model changes and integration work. An updated Stream depletion analysis along with Basin Water Supply and Basin Water Demands analysis are nearing completion. Conjunctive water management projects are also being simulated for project development.
Influence of wetland plant community types on water quality improvement in natural and restored wetlands of the Mississippi Delta
Year: Authors: Ervin G.N.
In an effort to quantify the specific linkages between wetland plants and water quality in Mississippi Delta wetlands, we assessed vegetation and water quality in 30 wetlands, including 24 Wetland Reserve Program (WRP) restorations and six naturally occurring wetlands. Our goal was to examine interactions among water quality parameters and plant species to determine which plant species assemblages appear to most strongly influence nutrient and sediment concentrations in these wetlands. We found substantial differences in the hydrology of restored, versus naturally occurring wetlands, and these differences were correlated with differences in plant species diversity among wetlands. We did not see significant correlations between specific plant species and water quality parameters, but we did find that some plant growth forms were consistently correlated with such water quality parameters as pH, conductivity and nitrate concentrations. We will be working with the USDA NRCS in an effort to translate results of this work into information useful for the design of future restorations, such that they can yield the greatest improvements in water quality while also providing other benefits, such as wildlife habitat, for the Mississippi Delta.
Responses of water quality and wetland plant communities to multi-scale watershed attributes in the Mississippi Delta
Year: Authors: Ervin G.N., Kroger R.
This project aimed to understand the influence of local and landscape factors in shaping wetland functions within the Mississippi Delta. An understanding of scale effects on function is both critical and timely for Delta wetlands. Recent efforts aimed at restoration of marginal agricultural lands to wetlands have been sponsored through government and private wetland restoration projects. Unfortunately, the outcomes of these projects in terms of conservation goals are unknown. This means that decisions to enroll lands in such programs continue to be made without a full evaluation of specific practices that may result in the greatest conservation benefits. Additionally, with little to no long term monitoring conducted on many sites, the ultimate outcome of restoration efforts is unknown. A better understanding of the influence of local and landscape factors on wetland functions in existing restorations will permit more effective targeting of limited resources towards future restorations.<br /><br />This two-year study resulted in a large database relating to soil and water variables and plant species inventories of 24 Wetlands Reserve Program (WRP) restorations and six natural wetlands within the northern half of the Delta. Thus far, our analyses have indicated that WRP wetlands harbor high levels of plant species diversity and that surrounding conservation practices may be buffering these wetlands from any potential negative impacts of agricultural land use within the Delta. An experimental study of seed bank responses to flooding suggested that some of the observed differences in wetland plant diversity may be attributed to the duration of flooding in natural wetlands. Ongoing analyses are aimed at more detailed examination of how within-wetland vs. landscape factors may be shaping water quality and plant species assemblages within these wetlands.
The Effect of Government Structure and Size on the Performance of Mississippi Community Water Systems
Year: Authors: Barrett J.
Mississippi has an abundant supply of underground aquifers which are utilized by community water systems as their source for drinking water. As the demand for water increases through the increasing population and the influx of industries, there is a need to manage the consumption and distribution of this valuable resource. The initial management forms created with the constructing of Mississippi's water supplies have experienced peaks and valleys of performance. Since their inception, the Mississippi drinking water industry has spawned new regulations, new management options, and creative ideas to promote a safer more efficient community water system. Over the past 15 years, Mississippi has seen several centralization efforts occur, where a municipality, utility district, or a rural water association merges with one or multiple adjoining or close proximity community water systems. This results in one of the three legal structures of a community water systems increasing in size in an effort to heighten performance. It will be valuable to see which of the consolidating government structures has been able to achieve optimal performance. This research analyzes the size (population) and government structures of Mississippi community water systems and will determine if economies of scale and economies of scope exist. This study will reveal the affect that size and government structure have on the overall performance of Mississippi community water systems.<br /><a href="http://wrri.msstate.edu/conference/pdf/barrett_jason2015.pdf">Download the presentation</a>
Comparison among three methods for suspended-sediment sampling of the Mississippi River at Vicksburg, Mississippi
Year: Authors: Welch H.
Depth- and- width- integrated isokinetic sampling techniques have been used to collect suspended-sediment samples in the Mississippi River by the U.S. Geological Survey (USGS) since the early 1970s as part of the National Stream Quality Accounting Network program. Collecting water-quality samples is critical in order to measure and understand chemical and sediment transport, but sampling can be challenging in terms of logistics, cost, and safety. The USGS has established suspended- sediment sampling protocols to ensure that samples are collected in a consistent and uniform way in streams across the country for data comparability and interpretation. However, variants of the traditional method have evolved to account for possible loss of equipment, improved safety to personnel, and potential loss of samples "contaminated" with bed material. Questions have recently arisen regarding the comparability of suspended-sediment data at selected water-quality stations along the lower Mississippi River. Three methods of sample collection have been used since the early 1980s. They include the traditional method, in which the sampler is lowered to the bottom of the channel, and two variants of that method, which consist of either lowering the sampler to 90% of the total stream depth or lowering the sampler to 2 feet from the bottom of the channel. From April through August 2013, the USGS collected suspended-sediment samples along a transect of the Mississippi River above Vicksburg, Mississippi using the three different methods. The collected data will be used to assess if: (1) sample collection techniques are reproducible, (2) data collected using the three different methods are comparable, and (3) the traditional method biases the suspended-sediment sample toward the sand-size fraction. <br /><a href="http://wrri.msstate.edu/conference/pdf/Welch_heather2015.pdf">Download the presentation</a>
Use of Small Unmanned Aerial Vehicle in Agricultural Research
Year: Authors: Pennington D.
Recent development in electronic and software systems have made the use of small unmanned aerial vehicles (UAVs) practical for a wide range of applications. In the research presented here, an electric powered, 5 lb, 66 inch wing span, foam fixed wing model airplane was fitted with a 3D Robotics, APM 2.6 autopilot for guidance and two point-and-shoot Canon cameras for imagery collection. One camera is a 1.2 MP RGB camera and the filter in the second camera was changed to allow the red band to receive and record intensity of near infrared electromagnetic energy. Programmed flight missions were flown over 3 different fields at 100 meters above ground level or less. The same missions were flown over each field on several dates. The total number of individual images collected for each field ranged from 80 images for small plot areas to 325 images for a 65 acre production soybean field. Individual georeferenced tagged images were stitched into a single georeferenced orthophotograph mosaic for each field using the Dronemapper data system available commercially through the internet. Yield data was collected from the plot areas using conventional plot harvesting methods. Yield data from two production fields were obtained from yield data collected during harvest with combines fitted with yield monitoring systems. The remotely sensed imagery data and the spatial yield data were compared and analyzed with QGIS (free GIS software) and spreadsheets. Comparisons of spatial imagery and yield data are being made and the results of those analysis will be presented. Operational experience of a UAV system will also be discussed. <br /><a href="http://wrri.msstate.edu/conference/pdf/pennington_dean2015.pdf">Download the presentation</a>
Use of Small Unmanned Aerial Vehicle in Agricultural Research
Year: Authors: Pennington D.
Recent development in electronic and software systems have made the use of small unmanned aerial vehicles (UAVs) practical for a wide range of applications. In the research presented here, an electric powered, 5 lb, 66 inch wing span, foam fixed wing model airplane was fitted with a 3D Robotics, APM 2.6 autopilot for guidance and two point-and-shoot Canon cameras for imagery collection. One camera is a 1.2 MP RGB camera and the filter in the second camera was changed to allow the red band to receive and record intensity of near infrared electromagnetic energy. Programmed flight missions were flown over 3 different fields at 100 meters above ground level or less. The same missions were flown over each field on several dates. The total number of individual images collected for each field ranged from 80 images for small plot areas to 325 images for a 65 acre production soybean field. Individual georeferenced tagged images were stitched into a single georeferenced orthophotograph mosaic for each field using the Dronemapper data system available commercially through the internet. Yield data was collected from the plot areas using conventional plot harvesting methods. Yield data from two production fields were obtained from yield data collected during harvest with combines fitted with yield monitoring systems. The remotely sensed imagery data and the spatial yield data were compared and analyzed with QGIS (free GIS software) and spreadsheets. Comparisons of spatial imagery and yield data are being made and the results of those analysis will be presented. Operational experience of a UAV system will also be discussed.
Improving N and P Estimates for Swine Manure Lagoon Irrigation Water
Year: Authors: McLaughlin M.R., Brooks J.P., Adeli A., Jenkins J.N.
Nutrient management plans (NMPs) for confined animal feeding operations (CAFOs) require a record of N and P loads from manure land-applications, including irrigation with lagoon water. Mississippi regulations require nutrient records for lagoon irrigation water be based on at least one annual analysis. Research on swine CAFOs in Mississippi has shown that N and P levels in lagoon water, and the N:P ratio, follow predictable annual cycles, but vary significantly through the April to October irrigation season. Nutrient estimates based on a single annual analysis may not account for this variability and may over- or underestimate nutrient loads and yield inaccurate NMP records. The present study reports an improved method to more accurately estimate N and P loads in irrigation water from swine lagoons. Derived by analyses of data from Mississippi lagoons and other lagoon studies, the method used predicable annual cycles of N and P in lagoon water to fit lagoon-specific models and produce date-based data on nutrient levels. Data were converted to tables displaying estimated N and P levels in the lagoon water for each day of the irrigation season. The farm manager uses the calendar table to find estimated nutrient levels for the date of a respective irrigation event, multiplies those values by the volume of water applied per irrigated area, and enters the results in the NMP record. Similarity of curves from analyses of lagoons in Mississippi and other states suggests that the method can be applied using data from a single nutrient analysis for each lagoon. Although annual cycles followed polynomial models, the irrigation season could be reduced to simpler linear models. An interesting mathematical result from the seasonal linear model showed that lagoon water samples from early July, midway in the irrigation season, represented the average N and P levels for the season, therefore, making it possible to estimate N and P loads using the single analysis data without fitting the data to a seasonal model and calendar table. The accuracy of the single early July analysis approach without curve fitting and a calendar table was, however, dependent on lagoon water volumes being uniformly distributed throughout the irrigation season. Fitting a curve and producing a lagoon-specific calendar table was more accurate for estimating nutrient loads when irrigation events and volumes were not evenly distributed through the season. Both methods were more accurate than using a single analysis from early or late season nutrient concentrations.
Anammox bacteria as biocathode of Microbial Desalination Cell (ANXMDC)
Year: Authors: Kokabian B., Gude V.G.
Discharge of nitrogenous compounds from municipal and industrial wastewater effluents is of major concerns of today's world since it has negative effects including eutrophication and hypoxia in water bodies. On the other hand, an ongoing challenge to sustainability of wastewater treatment systems is to improve the energy efficiency and cost effectiveness in removing nutrient compounds. A solution to this challenge would be to use Anammox bacteria in devices called Microbial Desalination Cell (ANXMDC). ANXMDC is a promising technology which allows for simultaneous wastewater treatment and desalination of saline water with concurrent electricity production and nitrogen removal. Exoelectrogenic bacteria in the anode oxidize organic matter while autotrophic bacteria serve as biocathode to remove ammonia in an emerging anaerobic microbial process called anaerobic ammonia oxidation (anammox). For a proof-of-concept study, the ANXMDC was fed with synthetic wastewater as organic source in the anode chamber and anammox bacteria were used as biocathode. The ANXMDC produced 0.0896 V while 100% of ammonia (NH<sub>3</sub> as ammonium) and 88% of nitrite were removed from the cathode chamber with desalination efficiency of 53.66%. Our results demonstrate that effective batch acclimatization experiments enhanced electricity generation along with nitrogenous compound removal and desalination. This study shows that this system has potential for sustainable and cost effective treatment of nitrogenous compounds and energy recovery from wastewater.
Improving Port-Based Economic Development Marketing Websites
Year: Authors: Miller C.R., Kern T.
River and seaports are important assets for regional economic development. Many industries need to be located in close proximity or with efficient transportation connections to ports. Therefore, ports are important site selection factors for industrial attraction. The industrial site selection process typically involves an initial web-based screening of potential locations by consultants or internal real estate teams. Those few communities or states that appear to meet the criteria based on their websites are sent a Request for Information (RFI) seeking specific information. There is a final screening based on the RFI information before economic development negotiations begin so to be successful in industrial attraction certain information needs to be on a port's website or readily available. This research, which was part of the 2014 Mississippi Department of Transportation Statewide Port Needs and Marketing Assessment study, reviews the port related information requested from RFIs to compile a content analysis tool for evaluating port websites. Each of the 16 port websites in Mississippi and their associated economic development organization are evaluated using this checklist. Recommendations for marketing are developed that will improve industrial attraction and retention efforts by ports.
Impacts of reforestation/deforestation upon surface water quality in Mississippi River Basin
Year: Authors: Ouyang Y.
Among the world's largest coastal and river basins, the Mississippi River Basin (MRB) is one of the most disturbed by human activity. Changes in agricultural and forest practices, clearcutting in bottomland hardwood forests, and conversions from forests to agricultural lands are largely responsible for the increased nutrient, sediment, and other pollutant loads into the Mississippi River (MR) and the adjacent Gulf of Mexico (GOM). The excess nutrient load has resulted in the increased extent and severity of the seasonal hypoxic zones, the altered species composition, and the decreased overall health of aquatic communities in the MRB and adjacent GOM. Additionally, the elevated sediment load has been recognized as both a carrier and a potential source of contaminants in aquatic environments due to their adsorption of toxic constituents. In spite of numerous efforts have been devoted to investigating the relationships between the ecological and environmental consequences of deforestation and the benefits of reforestation, very few efforts have been devoted to scrutinizing and synthesizing the effects of reforestation on water quality in the MRB. This study was undertaken to investigate (1) impacts of deforestation on water quality (e.g., nutrients and sediments), and (2) effects of reforestation and forestry management practices on surface water quality. Synthesized the review findings, we have identified the relevant knowledge gaps and recommended future research needs to assist forest and water resource managers in making timely decisions for water quality improvements in the MRB and the adjacent GOM.
Subsurface Erosion in Response to Land Management Changes and Soil Hydropedology
Year: Authors: Wilson G.V., Rigby J.R., Dabney S.M.
Flow through macropores can be sufficiently rapid to cause internal erosion and, thereby, create soil pipes. Soil pedology and hydrology interact to determine the location of soil pipes, flow rates through soil pipes and rates of internal erosion. Soil pipes tend to develop in duplex soil in that water restricting horizons cause a proliferation of biopores at the interface and foster lateral subsurface flow by perching water. Internal erosion can enlarge these preferential flow paths to the extent that soil pipe's collapse, thereby forming flute holes, sinkholes and ephemeral gullies at the surface. The soil hydropedologic properties determine the erodibility of the pipe surfaces and shear forces acting on pipe walls. Little is known about the impact of past land management practices on soil pipe formation. This paper will review the connections between hydrologic and pedologic soil properties and the impact of changes in land use from cropland to forest and forest to pasture on soil pipeflow processes using observations of soil pipes in Goodwin Creek Experimental Watershed. Three adjacent catchments, all classified as the same soil series, were surveyed for pipe collapse features. One contained no pipe collapse features, while the other two exhibited 32.6 and 15.7 collapse feature ha-1. Soils in these catchments contain a fragipan that perches water and fosters lateral flows. Subsurface layers exhibit vulnerability to internal erosion. It appears that past land management practices, including removal of forested buffers and filling in historical gullies control to a large degree the location of soil pipes and the current hydrologic response of the catchment. This paper will use field observations to highlight gaps in our understanding of the hydropedologic processes associated with soil piping and their interaction with and/or response to land management practices.<br /><a href="http://wrri.msstate.edu/conference/pdf/wilson_glenn2015.pdf">Download the presentation</a>
Bottomland hardwood restoration and implications for water quality
Year: Authors: Frey B., Ouyang Y., Stoll J.
Over the last several decades, bottomland restoration efforts have established hundreds of thousands of acres of planted hardwood stands across floodplains of the Lower Mississippi Alluvial Valley (LMAV). Major goals of these afforestation efforts are to restore forest cover for the enhancement of wildlife habitat, soil conservation, and water quality. However, few studies have evaluated the effects of bottomland afforestation on soil and water quality, particularly in relationship to different sites conditions, planting mixtures, and over time as these afforestation stands mature. Studies have suggested that bottomland forest restoration could play an important role in carbon and nitrogen removal, particularly in connected floodplains in the LMAV. This presentation will review our research investigating stand development, growth and biomass of young (10-20 year old) planted oak stands and management activities that are being considered for these stands. We will also discuss our proposed research to investigate soil and hydrological processes in relation to stand development. Knowledge of stand growth, linked with soil and hydrological processes, is needed to evaluate the role of bottomland afforestation efforts in enhancing soil and water quality. This information will be important for addressing the impacts of these forest restoration efforts and identifying opportunities to improve their efficacy.<br /><a href="http://wrri.msstate.edu/conference/pdf/frey_brent2015.pdf">Download the presentation</a>
Improving Water Quality through Watershed Planning, Design and Innovative Outreach Activities
Year: Authors: Johnson K.
Mississippi State University's Gulf Coast Community Design Studio (GCCDS), in partnership with the Land Trust for the Mississippi Coastal Plain (LTMCP) and with input from community leaders and residents, is developing a Watershed Implementation Plan for Rotten Bayou Watershed in Hancock and Harrison Counties, Mississippi. In addition to developing a written plan, the work includes extensive education, community outreach, and demonstration projects of best management practices. Meaningful engagement is critical both to address conditions that cause nonpoint source pollution and to develop a plan that has good community buy-in to ensure implementation. Innovative engagement approaches are necessary in Rotten Bayou Watershed for two main reasons. First, there is currently very limited public access to the Bayou so few residents in the watershed have a direct connection to or an appreciation of the waterways they impact. Second, there are essentially two "communities" that make up the watershed: Fenton/Dedeaux and Diamondhead. Fenton/Dedeaux is a rural community with many residents that have deep roots in the area. Diamondhead is a planned retirement community that recently became Mississippi's newest city and is made up of many transplants to the area Effectively communicating with residents in these two communities; appealing to their different interests and values; and uniting them in the cause of improving water quality in Rotten Bayou requires multiple and creative approaches to outreach. The presentation will introduce conference attendees to the unique planning and outreach methods being utilized in developing the Rotten Bayou Watershed Implementation Plan. Strategies include working with non-traditional partners such as a churches, summer library reading programs, golf courses and an educational puppet show; utilizing social media and raffles to make participation appealing and accessible; and leveraging funding from NOAA's Gulf of Mexico B-WET Program to connect students at a local elementary school to the watershed planning work. The Watershed Implementation Plan for Rotten Bayou Watershed is funded in part by a grant from the EPA to the Mississippi Department of Environmental Quality under the provisions of Section 319(h) of the Clean Water Act along with State and local match.<br /><a href="http://wrri.msstate.edu/conference/pdf/johnson_kelsey2015.pdf">Download the presentation</a>
The Catalpa Creek Watershed Project and Watershed Demonstration, Research, Education, Application and Management (D.R.E.A.M.) Center
Year: Authors: Ingram R.
<p>A significant portion of Mississippi State University's (MSU) campus and property resides within the Catalpa Creek Watershed (referenced by USGS as the Red Bud-Catalpa Creek Watershed, HUC 12 #031601040601, and by MDEQ as MS #8090). This includes important MSU education and research facilities, such as the Mississippi Agricultural and Forestry Experiment Station's (MAFES) South Farm, which is used by numerous departments and programs. Unfortunately, some of MSU's land uses in this watershed may have contributed to the pollution of Catalpa Creek. Total Maximum Daily Load (TMDL) studies that apply to this watershed include those for sediment, nutrients, and pathogens. Each of these TMDLs recommend practices to reduce pollutant amounts to acceptable levels thereby providing improved habitat for the support of aquatic life and allowing for the attainment of applicable water quality standards.</p> <p>On April 2013, MSU, through the Mississippi Water Resources Research Institute (MWRRI), was designated a Center of Excellence for Watershed Management with the signing of a Memorandum of Understanding (MOU) between the Mississippi Department of Environmental Quality (MDEQ), Region 4 of the U.S. Environmental Protection Agency (EPA), and MSU. The MOU recognized that MWRRI had "demonstrated to the satisfaction of EPA and MDEQ that it has the capacity and capability to identify and address the needs of the local watershed stakeholders" and was charged to "work with colleges and universities in Mississippi to engage students (graduate and undergraduate), faculty and staff from the full suite of disciplines needed to adequately address specific watershed issues" and to "draw upon other local, state, federal resources and expertise".</p> <p>MWRRI, in its role as a Center of Excellence for Watershed Management, is advantageously positioned to bring resources together from various MSU departments and programs; nongovernmental organizations; and state and federal agencies to address the needs in the Catalpa Creek Watershed. This project will not only put appropriate BMPs on the ground in strategic locations in the watershed to restore water quality and habitat, but also establish a venue for watershed-based demonstrations, research, education, application and management.</p>
Automated identification of sediment sources and sinks: Tool development to support water quality planning
Year: Authors: Diehl T., Cartwright J.
Water-quality improvement practices, including sediment retention and channel restoration projects, are commonly hampered by incomplete knowledge of sediment-source locations and transport networks within watersheds. In particular, gully systems can undermine infrastructure and pose public safety hazards through active bed and bank erosion and excessive sedimentation near their outlets. High-resolution digital elevation models (DEMs) from Light Detection and Ranging (LiDAR) are a newly-available data source useful for investigating geomorphology of stream channels and gullies. Channel and gully networks derived from these DEMs offer much higher resolution than currently available topographic maps or map-derived stream networks. The U.S. Geological Survey is working in cooperation with the Tennessee Department of Transportation and the Southwest Tennessee Development District to develop automated tools to identify locations of erosion, sediment transport, and deposition within channel and gully networks, based on landscape characteristics derived from high-resolution DEMs. By automating the identification of hotspots of channel erosion (for example incised channels and gully heads) and sedimentation (for example over-widened shallow channels and valley plugs) this project will provide a tools for local and regional efforts related to water quality, channel restoration, infrastructure protection, and storm-water management.
Analysis of pervious concrete as a stormwater management tool using SWMM Modeling
Year: Authors: Abera L.E., Surbeck C.Q.
Stormwater runoff occurs when precipitation flows over the ground. Increase in impervious land cover due to urbanization causes excess stormwater runoff and affects the quantity and quality of receiving water bodies. The use of Low Impact Development (LID) controls is highly recommended to reduce the excess volume of stormwater runoff. LID controls include infiltration techniques such as pervious pavements, evaporation, and storage techniques to reduce the volume of runoff. In this study, performance assessment results of pervious concrete pavement at the University of Mississippi Law School parking area will be presented. The Law School was constructed in 2009 and is adjacent to a privately owned recreational pond. There is a high volume of stormwater runoff from the university area going to the pond, which prompts the university to implement LID tools, such as pervious pavement. Multiple in-place infiltration rate tests, using the ASTM C1701/C1701M-09 standard, were conducted to evaluate the effectiveness of the pervious pavement. Based on the test results, the average infiltration rate of the pervious pavement is 45.14 m/hr, which is less than the desired rate. The U.S. Environmental Protection Agency's Stormwater Management Modeling Tool (SWMM) was used to model the area and to quantify the volume of runoff that can be expected from different intensity storms. Results show that pervious concrete is more effective for a low intensity, long duration storm than for a high intensity, short duration storm.
An Update on the Mississippi Irrigation Scheduling Tool
Year: Authors: Tagert M., Linhoss A., Rawson J.C., Sassenrath G.
Since the 1970's, groundwater levels in the Mississippi Alluvial Aquifer have decreased as the number of irrigated acres in the Mississippi Delta has increased. Today, there are roughly 18,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer. As concern has grown over groundwater declines, farmers have been implementing more irrigation conservation measures, such as the use of surge valves and computerized hole selection, which improve irrigation application methods. Some farmers are also using soil moisture sensors to improve irrigation timing, although this can be cumbersome, especially if irrigating a large number of fields. The Mississippi Irrigation Scheduling Tool (MIST) is a web-based irrigation scheduling tool designed to help farmers manage and schedule irrigation in a humid climate. The tool provides an estimate of crop water use based on a "checkbook" approach that determines the water balance of the soil, plus water from rainfall or irrigation, minus water used by the crop or evaporated from the soil. Daily evaporation is calculated using the modified Penman-Monteith equation. The system automatically notifies the farmer if irrigation is required when the available soil moisture balance falls below a set threshold. MIST, which is being tested in selected areas in the MS Delta region, has a web interface that allows producers to access their information from anywhere through tablet computers or smart phones. This presentation will give an update on the MIST project and summarize progress to date.
Measuring the uncertainty and sensitivity of the Mississippi Irrigation Scheduling Tool (MIST)
Year: Authors: Linhoss A., Tagert M., Bukah H.
The Mississippi River Valley Alluvial Aquifer has seen dramatic declines due to pumping for irrigation in northwestern Mississippi. Irrigation scheduling saves water and energy without sacrificing yield through the optimal frequency and duration of water applications. Models, based on based on crop, soil, and climatic data, can be used for irrigation scheduling. The Mississippi Irrigation Scheduling Tool (MIST) is one such model. MIST uses the Penman-Montieth equation, along with crop coefficients, and the Soil Conservation Service curve number method to calculate runoff and evapotranspiration in a field. The resulting water balance can be used to schedule irrigation events. When using a model, such as MIST, for management purposes, it is important that the user be aware of the reliability or uncertainty of the model. Furthermore, model calibration can be optimized by identifying the most important driving parameters within a model. The objective of this research was to conduct a global sensitivity and uncertainty analysis of the MIST model to quantify model reliability and identify the most important model parameters. In order to provide a realistic representation of the model's uncertainty and sensitivity, parameter probability distributions were based on measured values and compared to results that used generic percentages. Six global sensitivity analysis methods were employed to understand how those methods differ (Sobol, FAST, Morris, random, quasi-random, and Latin-hypercube sampling). The results show that the sensitivity analysis methods return similar results. However, the method by which the probability distributions were determined were important in determining the results. These results are useful in developing better modeling tools and can help farmers and managers successfully apply MIST model recommendations.<br /><a href="http://wrri.msstate.edu/conference/pdf/linhoss_anna2015.pdf">Download the presentation</a>
Climate Change and Coastal Eutrophication
Year: Authors: Rabalais N.N.
The world's climate has changed and human activities will continue to contribute to the acceleration of greenhouse gases and temperature rise. The major drivers of these changes are increased temperature, altered hydrological cycles and shifts in wind patterns that might alter coastal currents. Increasing temperatures alone have the potential to strengthen pycnoclines in estuarine and coastal waters, but lower surface salinity (e.g., from increased freshwater runoff) would be more of a factor in stratifying the water column. The combination of increased nutrient loads (from human activities) and increased freshwater discharge (from GCC) will aggravate the already high loads of nutrients from the Mississippi River to the northern Gulf of Mexico, strengthen stratification (all other factors remaining the same), and worsen the hypoxia situation. Reduced precipitation, on the other hand, would lower the amount of nutrients and water reaching the coastal zone and, perhaps, lead to oligotrophication and reduced fisheries productivity, or perhaps alleviate hypoxia. The increase or decrease in flow (whichever occurs), flux of nutrients and water temperature are likely to have important, but as yet not clearly identifiable, influences on hypoxia. In anticipation of the negative effects of global change, nutrient loadings to coastal waters need to be reduced now, so that further water quality degradation is prevented.
NOAA's Gulf of Mexico Hypoxia Watch
Year: Authors: Beard R.H.
The Gulf of Mexico Hypoxia Watch is a cooperative project of NOAA's National Marine Fisheries Service (NMFS), Southeast Fisheries Science Center (Pascagoula and Stennis Mississippi Labs), and NOAA's National Coastal Data Development Center (NCDDC). The purpose of the project is to collect measurements of bottom-dissolved oxygen using a Conductivity, Temperature, Depth (CTD) profiler with an oxygen sensor. The NOAA ship <i>Oregon II</i> goes to sea in June and July for the Southeast Area Monitoring and Assessment Program (SEAMAP) groundfish survey and collects the CTD measurements along with SEAMAP biological data. The CTD casts are done in a random pattern along the continental shelf, from the Texas/Mexico border to southern Florida, in water depths between 10 m and 200 m. After data processing, the bottom (deepest) oxygen values are sent via email to NCDDC where they are contoured and mapped. The contours show estimations of where high and low oxygen levels are likely occurring. The dissolved oxygen values range from 0 to 8 mg/L and the water is considered hypoxic if the value is 2 mg/L or less. During the cruise, values are often mapped daily, providing a near-real-time picture of the health of the Gulf. Currently, the Hypoxia Watch project includes data from 2001 through 2014. To access the data, view maps, or consult metadata for the project, please see <a href="http://www.ncddc.noaa.gov/hypoxia/"> http://www.ncddc.noaa.gov/hypoxia/</a>.<br /><a href="http://wrri.msstate.edu/conference/pdf/toft_tiffany2015.pdf">Download the presentation</a>
New Approaches and Analytical Tools for Studying Mercury in the Gulf of Mexico: Sources and Transformations
Year: Authors: Cizdziel J., Bussan D.
Monomethylmercury (MMHg), a neurotoxin produced primarily by sulfate reducing bacteria in aquatic sediments, readily biomagnifies up the marine food chain. Consumption of fish containing high levels of MMHg can lead to adverse health effects in both humans and wildlife. This is of particular concern in the northern Gulf of Mexico (GoM) because, on average, residents of the Gulf Coast consume more marine fish than other U.S. residents, and because GoM fish tend to have higher levels MMHg than fish from other coastlines.<sup>1,2</sup> Moreover, because the economy of the Gulf coast states is intricately linked to the GoM through fishing (both commercial and recreational), understanding the distribution, levels and cycling of MMHg is vital to the long-term health and stability of the region. Whereas there has been much progress on understanding the fate, transport and transformation of mercury in aquatic and terrestrial environments, there remains a major gap in understanding of the sources and pathways of MMHg entry into food webs in the northern GoM. Recent advances in analytical techniques now offer an opportunity to answer fundamental questions such as where in the GoM is MMHg produced from inorganic mercury, and where is MMHg most bioavailable. Recent work demonstrates the potential of the use of enriched stable isotopes to simultaneously determine methylation and demethylation rates in sediments,3 and for stable isotopes to serve as probes for reaction pathways and to evaluate the source/history of mercury in samples.4 In this talk and associated poster, we will introduce these techniques and show how they can be used to advance our understanding of mercury cycling and transformation in the GoM. We will include recent results from our own research utilizing these techniques to study sediment from wetlands from the Mississippi Delta and from the cold seeps in the northern GoM.<br /><a href="http://wrri.msstate.edu/conference/pdf/cizdziel_james2015.pdf">Download the presentation</a>
Monitoring Network Design to Assess Potential Water-Quality Improvements Associated with the Mississippi Coastal Improvement Program in the Mississippi
Year: Authors: Rebich R.A., Wilson D.T., Runner M.S.
The Mississippi barrier islands have undergone extensive changes in their formations over the past several decades primarily due to wind erosion and storm surge from hurricanes. In 1969 during Hurricane Camille, a "cut" formed through Ship Island bisecting it into what is known today as East and West Ship Islands. In addition, a tremendous amount of damage and erosion occurred on the two islands and to the shoreline of the Mississippi coast in the aftermath of Hurricane Katrina in 2005. In 2009, the Mississippi Coastal Improvement Program (MSCIP) was enacted by the U.S. Army Corps of Engineers (COE), in conjunction with other Federal and State partners, with the purpose of reducing future storm damage along the Mississippi Gulf Coast. MSCIP includes construction projects along the shoreline of Mississippi as well as major restoration efforts associated with the barrier islands. One such project is to restore Ship Island by filling in the "cut" (also known as "Camille Cut") between East and West Ship Islands thus creating one island again. The restoration effort to close Camille Cut and recreate a singular Ship Island could cause shifts in water quality and aquatic habitat in the vicinity of Ship Island and other areas within the Mississippi Sound. Of particular interest will be the potential increase in turbidity and suspended sediments during the construction phase. Adaptive management planning associated with MSCIP included establishment of a long-term monitoring network design to collect water-quality data to be used as indicators of change for comparison to biological response variables also collected during the study period, and to be used as input for modeling of the Mississippi Sound system to document longer-term change in response to restoration activities in the future. The U.S. Geological Survey (USGS), in cooperation with the COE-Mobile District, has implemented a water-quality monitoring network design in the Mississippi Sound to help achieve programmatic and adaptive management goals of MSCIP. Specifically, two locations near Ship Island have been outfitted to continuously monitor specific conductance (salinity), temperature, dissolved oxygen and turbidity. Nine locations located near Ship Island and near the remaining barrier islands will be visited eight times per year, and during each visit, the same water quality parameters are measured and discrete water quality are collected for nutrient and sediment analysis. This project is a 5-year project to include 1 year of pre-construction, 2 years of construction, and 2 years of post-construction data collection.<br /><a href="http://wrri.msstate.edu/conference/pdf/rebich_richard2015.pdf">Download the presentation</a>
Using low-grade weirs as a best management practice for phosphorus and sediment mitigation
Year: Authors: Baker B., Kroger R., Prevost D., Pierce T.
Widespread concern for nutrient enrichment of freshwater and marine environments led to the formation of the Mississippi River/Gulf of Mexico Hypoxia Task Force, which aims to reduce riverine loads of total phosphorus from the Mississippi and Atchafalaya River Basins by 45% by 2015. Recent studies highlighted advantages of using low-grade weirs, situated in drainage ditches, to reduce effluent nutrient loads, as opposed to traditional control drainage practices such as variable height risers. The overall objective of this study was to quantify the effects of low-grade weir frequency and spatial arrangement on phosphorus and sediment reduction efficiencies of agriculture runoff using field-based experimental design in the Mississippi Delta. Low-grade weirs are an innovative, relatively low-cost and low-technology best management practice in comparison to large water reservoir systems or bioreactors, making them a suitable option for large and small-scale farmers alike. Study sites were located in the Yazoo Delta Region of Northwestern Mississippi. Results of the phosphorus and sediment load reduction efficiencies of low-grade weirs showed positive reductions in most ditches, with and without weirs. Low-flow and storm-flow outflow concentrations were found to be variable between sites, with no clear significant differences between sites with or without weirs. Mean percent differences between low flow and storm flow at each site resulted in low-flow samples having significantly lower phosphorus and sediment concentrations than during storm flows. A complimentary investigation of hydraulic retention highlighted that control ditches, while not engineered for such purposes, retained water. However, because this was an unintended consequence, these systems also exhibited flooding into producer fields; this phenomenon did not occur in ditches with weirs.
Assessment of tailwater recovery system and on-farm storage reservoir efficacies: Quality issues
Year: Authors: Omer A.R., Czarnecki J.M.
The Lower Mississippi Alluvial Valley is economically important due to its highly productive agricultural land. However, producers in this region face two predominant environmental issues that are inherently linked to the intensity of the agricultural industry in this region. First, intensive agriculture practices which have resulted in increased surface transport of nutrient-laden sediments, contributing to eutrophication in receiving waters and to the Gulf of Mexico Hypoxic Zone. Second, current water withdrawals from the Mississippi Alluvial Aquifer for irrigation are not sustainable. These issues threatening environmental resources necessitate use of best management practices and groundwater conservation. This research investigates systems of best management practices as water resource conservation methods. Such practices include surface water capture and irrigation reuse systems. Referred to as tailwater recovery systems (TWR), this practice consists of a tailwater recovery ditch which may be paired with on-farm storage reservoirs (OFS). Five case studies of different TWR were monitored for nutrients during a single growing season at: inflow, edge of field, TWR, OFS, and overflow locations. Investigations highlight functionality for nutrient recycling, and descriptions of nutrient loss mitigation. Additional research includes quantification of nutrients lost and captured during rice patty drains into TWR using <i>in-situ</i> nitrate sensors. Although research on these systems continues, initial results from three TWR in 2013 show over 278 million liters of water being recycled applying a mean of 0.96 kg/ha total nitrogen and 0.15 kg/ha total phosphorus. These systems are proving successful in holding water on the landscape, recycling that water, and therefore nutrients. Thereby preventing those nutrients from being lost to downstream waters. This suggests that TWR have much promise for water resource conservation in the Lower Mississippi Alluvial Valley.<br /><a href="http://wrri.msstate.edu/conference/pdf/omer_austin2015.pdf">Download the presentation</a>
Contribution of total dissolved phosphorus in irrigation runoff from the Mississippi River Valley alluvial aquifer to phosphorus concentrations in a D
Year: Authors: Welch H.L., Rose C.E.
Water-quality of the Mississippi River Valley alluvial (MRVA) aquifer has the potential to influence water quality of streams located in the lower Mississippi River Valley either through irrigation runoff from fields during the growing season (May through August) or at times of baseflow when streams are comprised of mostly groundwater. Previous studies of groundwater from the MRVA aquifer have shown concentrations of total dissolved phosphorus ranging from 0.12 to 1.2 milligrams per liter (mg/L). These concentrations exceed 0.1 mg/L, which is the desired goal established by the U.S. Environmental Protection Agency for the prevention of nuisance plant grown in streams. In addition, watersheds in the lower Mississippi River Valley have been identified as having some of the highest total phosphorus yields in the Mississippi River basin, although application of phosphorus fertilizers to land in the basin is minimal. The contribution of phosphorus from the alluvial aquifer to the total phosphorus loads in the basin has not been determined. From June through September 2014, the U.S. Geological Survey conducted a study near a rice field located in Issaquena County, Mississippi, to quantify the effect of irrigation runoff on water quality in a small ditch draining the field. Thirteen groundwater samples were collected from a well screened in the MRVA aquifer used to irrigate the rice field. In addition, runoff samples were collected downstream of the well at two locations: (1) from a water furrow that drains the rice field and (2) from a ditch immediately downstream of the water furrow. All samples were analyzed for water temperature, pH, dissolved oxygen, specific conductivity, alkalinity, iron, manganese, orthophosphate, and total phosphorus. State and Federal agencies can use the results of this study to help with the establishment of nutrient reduction strategies in the lower Mississippi River Valley.
Characteristics of Phosphorus in Agricultural Landscapes
Year: Authors: Oldham L., Cox M.S., Ramirez-Avila J., Kingery W.L.
Phosphorus (P) management presents a conundrum in the diverse soils of Mississippi. This required plant nutrient is naturally abundant in bioavailable forms in many alluvial plain region soils (Delta), yet native soil P levels restrict productivity in some Coastal Plain region soils. However, some Coastal Plain and Jackson Prairie soils have elevated bioavailable P from past management with copious amounts of animal production by-products. Phosphorus movement from soil to surface waters is implicated in environmental degradation such as Gulf of Mexico hypoxia, yet P fertilizers are not widely used due to high levels of native labile P in the Delta. There exists a need for better understanding P properties and dynamics to improve nutrient and landscape management so the appropriate management practices are targeted to specific, unique regions of Mississippi. In this paper we review, using molecular to landscape scales of reference: P forms found in soils and surface waters, the relevant chemistry, plant uptake mechanisms, and movement in the landscape. The implications for management will be discussed.<br /><a href="http://wrri.msstate.edu/conference/pdf/oldham_larry2015a.pdf">Download the presentation</a>
Design and Construction of a Step Pool Storm Conveyance (SPSC) System on an Unnamed Tributary to Joe's Branch, D'Olive Bay Watershed, Baldwin County, Alabama
Year: Authors: Burcham W.
A Step Pool Storm Conveyance (SPSC) system has been constructed to restore a severely eroded ephemeral drainage on a tributary to Joe's Branch within the D'Olive Creek watershed in Baldwin County, Alabama. The project represents implementation of one of the management measures recommended in a comprehensive watershed management plan (WMP) developed for the area. The SPSC project was primarily funded through a Section 319 (nonpoint source) grant from the Alabama Department of Environmental Management (ADEM) to the Mobile Bay National Estuary Program (MBNEP). Additional funding for the project was provided by the Alabama Department of Transportation (ALDOT), with the cooperation and support of many others. The objective of an SPSC system is to convert and dissipate, through storage pools and sand seepage filters, surface storm flow to shallow groundwater flow. SPSC systems typically are comprised of a series of shallow aquatic pools, riffle grade control, native vegetation, and an underlying sand/organic filter bed media. An SPSC system is intended not only to provide a stable drainage pathway for higher flows, but to attenuate and/or retain lesser flows and facilitate water quality treatment. SPSC systems have been used in other parts of the country. Notably, in Anne Arundel County, Maryland, there have been several applications spanning over a decade, and the County has developed specific design guidelines for their construction. However, to our knowledge, an SPSC or similar system has not been evaluated for the conditions found in the north Gulf coastal region of south Alabama This presentation will discuss the engineering design and construction of the SPSC demonstration project in Spanish Fort, Alabama. Participants will be presented with information to identify when and why a SPSC may be an effective measure to stabilize and enhance hydrologic systems. Post-construction stormwater monitoring as performed by the Geological Survey of Alabama (GSA) will be discussed, along with "lessons learned". In addition, participants will be presented with future projects where these measures are currently being planned using different constraints.
Comparing nekton communities between fringing coastal marshes and adjacent seagrass beds
Year: Authors: West L., Moody R., Cebrian J., Aronson R., Heck K., Byron D.
Trawls and fyke nets are common sampling methods used in aquatic ecosystem studies. Sampling by trawls, which can be used to target seagrass-associated communities, is fundamentally different from sampling with fyke nets, which are positioned at fringing marsh edges to passively collect marsh organisms as the tide recedes. Thus, the two methods potentially differ in efficiency with respect to the numbers and types of organisms they can collect. In this study, we use a two-year data set to compare the community structure of marsh- and seagrass-associated nekton among five sampling sites in the northern Gulf of Mexico. We compare four metrics among sites, habitats, and sampling equipment: (1) total nekton abundance; (2) total abundance excluding the daggerblade grass shrimp <i>Palaemonetes pugio</i>, which is a numerically dominant species that may mask abundance patterns of other species; (3) total abundance of blue crabs and penaeid shrimp, the most abundant species after P. <i>pugio</i> and of commercial importance; and (4) nekton community structure. Variations in community structure between these aquatic habitats are discussed in light of differences in gear efficiency and inherent differences in the structural complexity and accessibility of each habitat to mobile fish and invertebrates. Our findings contribute to an emerging understanding of the potential for functional redundancy between fringing salt marshes and seagrass meadows, with emphasis on implications of this redundancy (or lack thereof) for commercially important species.
Buffering Wave Buffers: Implications for Accelerating Restoration Efforts in the Marsh-Mangrove Ecotone
Year: Authors: Macy A., Cebrian J., Cherry J.
With milder winter temperatures, the black mangrove <i>Avicennia germinans</i> has been expanding its range poleward into temperate salt marshes, forming an ecotone of mixed vegetation between two ecosystem-defining vegetations (Mangrove forest and <i>Spartina</i> salt marsh). In stable conditions, <i>Avicennia</i> outcompetes <i>Spartina alterniflora</i>, while occasional disturbances favor <i>Spartina</i>. Restoration efforts along the northern Gulf of Mexico will need to account for these interspecies interactions, and understanding stress tolerance thresholds of the climax species (<i>Avicennia</i>) in the field may offer an accelerated path to ecosystem stability and faster return on ecosystem services. I will transplant two groups of seedlings, aged 6-12 months old and 18-24 months old, into high and low energy wave environments. There are several created wetland areas in Bayou Lafourche (LA) dominated by early stages of wetland colonizatio (<i>i.e. Spartina alterniflora</i>). <i>Spartina</i> has been suggested as a wave buffer f <i>Avicennia</i>, aiding in the succession to an <i>Avicennia</i>-dominated system, so treatments will also include areas where <i>Spartina</i> has been clipped. Finally, fertilizer will be applied to half the plots to stimulate a decrease in the root: shoot ratio, possibly making <i>Avicennia</i> more vulnerable to uprooting from waves. Project scheduled to start this summer.
Non-linear downward flux of water in response to increasing wetland water depth and its influence on groundwater recharge, soil chemistry, and wetland
Year: Authors: Davidson G.
Many oxbow lake-wetland systems in the Mississippi River floodplain are perched above the regional water table, resulting in a downward hydraulic gradient. Fine grained sediments that accumulate in these environments limit downward flow, but fallen tree trunks and limbs introduce heterogeneity and isolated pockets of higher hydraulic conductivity. Normally, flux is proportional to the gradient, but previous work by the PI suggested that the relationship between water depth and downward flow in these systems can be non-linear. Studies in Sky Lake, in the Delta region of Mississippi, have documented minimal vertical movement of water until a threshold water depth is reached. Above the threshold, abrupt changes in soil chemistry have been observed as water begins moving downward, which may in turn influence the growth of wetland trees. The role of oxbow lakes as points of groundwater recharge is also largely unknown. Though oxbow-lake bottom-sediments typically serve as barriers to flow, the heterogeneity that exists in the wetland perimeters may provide conduits for vertical flow that bypasses the surficial clay and silt deposits.<br /><br />The project focused on the influence of changing water depth in Sky Lake, MS, in Humphreys County, where an elevated boardwalk into the heart of an old-growth bald-cypress wetland made it possible to mount equipment for long-term monitoring of a variety of environmental parameters (Fig. 1). The study focused on both the identification of non-linear responses to changing water depth, and its potential impact on tree growth and groundwater recharge. Possible non-linear downward flux in response to increases in wetland water depth was investigated using a series of redox probes at two depths in the sediment to monitor changes in redox potential that might accompany changes in water depth. Significant downward flow of oxygenated surface water should result in a shift to higher redox potentials. The impact on baldcypress tree growth was assessed using two sets of tree measurements: radial growth and sap flow rates. In order to link any changes in tree growth to water level, a series of additional variables were also measured that could also influence growth and mask a water-depth effect. These included temperature, relative humidity, and precipitation. Groundwater response was monitored by measuring the level of water in an abandoned irrigation well in the center of the oxbow meander loop.
Improving flow estimates at un-gaged streams in southwest Mississippi
Year: Authors: Runner M., Stocks S.
Understanding low flow characteristics of streams is a critical concern of State water resource managers. How streams react to drought or long periods of low flow can affect multiple water use issues such as irrigation, municipal and industrial water supplies, fish and wildlife conservation, and dilution of waste. Estimates of the 7-day, 10-year (7Q10) low flow for streams in Mississippi are used as basic criterion for permitting of both waste discharges and water withdrawals. It is assumed that 7Q10 adequately addresses assimilative capacity in the stream for dilution of pollutants and also protects aquatic life during low flow periods. Therefore, accurate estimates of 7Q10 low flow values and potential impacts to water quality and biological response are essential for proper management of the State's water resources to balance aquatic health with economic development. 7Q10 low flow estimates for Mississippi streams have not been updated since 1991. In addition, potential shifts in water quality during periods of low flow have been infrequently documented in Mississippi streams, if at all. Sudden changes in dissolved oxygen, pH, and temperature during low flow periods could have tremendous impact to biological communities in streams. Therefore, it is necessary to obtain both water quantity and quality data in streams to fully understand the impact of critical low flow periods. The U.S Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, collected streamflow data at 33 locations in southwest Mississippi to improve the ability of resource managers to estimate streamflow at ungaged locations based on current flow conditions at nearby reference gages. These data will be used to update 7Q10 computations for streams in southwestern Mississippi and to help determine the potential effects of low flows on water quality in the selected streams A total of 292 site visits were made between August 12 and October 30, with each site visited up to 10 times. During the site visits, water level, stream discharge, and water-quality field parameters were measured and recorded. Additionally, at 25 sites, water-quality instruments were deployed to measure field parameters over a 24-48 hour period. There were 245 streamflow measurements made with flows ranging from 0.004 to 142 cfs. There were 290 sets of discrete water-quality field parameter readings and 25 sets of time-series water quality data collected.
Inter-relationships of Coastal Water Quality, Ecosystem Health, Human Health, and Socioeconomics
Year: Authors: Ingram R.B.
Humans are a terrestrial species, we're also a social species. Our activities impact all environmental media in which we live; surface and ground water quality and quantity, air quality, aquatic and wildlife habitat, ecosystem structure, and climate. In a recent national report on water quality in the United States, 45% of assessed stream miles, 47% of assessed lake acres, and 32% of assessed bays and estuarine square miles were classified as polluted. Mississippi's current 303(d) List identifies 21 impaired water bodies in the Coastal Streams Basin, Lower Pascagoula River Basin, and Lower Pearl River Basin. In this same area 45 TMDLs have been developed. During 2014, 44 beach closures and/or water contact advisories were issued. Water quality, ecosystem health, and human health are all inextricably linked. Backed by science, acknowledgement of this is reflected in the tiered surface water designated use categories inherent in Mississippi's water quality protection standards (public water supply, shellfish harvesting, recreation, and fish and wildlife) all designed to collectively protect water quality, ecosystem health, and human health. Likewise, a strong relationship exists between water quality and socioeconomics at all scales, from the individual to the local community to the larger society. A significant portion of the coastal economy depends upon water quality to support industrial development and the creation of jobs, for the maintenance of healthy ecosystems and harvesting of marine resources, and to sustain the Gulf Coast's traditions, cultures, and quality of life.<br /><a href="http://wrri.msstate.edu/conference/pdf/ingram_richard2015.pdf">Download the presentation</a>
Utilizing NASA Earth Observations to Assist the Audubon Mississippi Coastal Bird Stewardship Program with Habitat Monitoring and Restoration Planning Activities
Year: Authors: Barrett S., Beasley B., Wylie L., McDaniel B.
Coastal and migratory bird habitats in Mississippi are highly dynamic and constantly threatened by human activity. Today, these coastal and migratory species can be found on managed public lands. However, as of 2014, the Pascagoula River Audubon Center (PRAC) and the National Fish and Wildlife Foundation (NFWF) reported shorebird populations in coastal Mississippi have declined. In response, the Mississippi Audubon Coastal Bird Stewardship Program (CBSP) plans to focus habitat management on approximately twenty sites in coastal Mississippi. Activities includes planning and conducting standardized monitoring, implementing best-practice restoration projects, and a campaign to educate diverse audiences to increase understanding of the threats to and environmental and societal benefits of coastal and migratory birds. To support these efforts, this NASA DEVELOP project used current Landsat 8 OLI imagery to produce habitat classification maps that incorporated land use land cover, vegetation health, and water quality indices of areas in coastal Mississippi where these vital bird habitats are located. The project yielded maps for declining coastal bird species such as the least tern. End products and methodologies aided end-users in focusing habitat restoration efforts based on individual species' propensity to a particular area.
The Mississippi Delta, the MAV and the World: The Groundwater Crisis - is there any hope?
Year: Authors: Johnson D.R.
Mankind has been overdrawing its aquifers for more than 20 years in order to feed the ever expanding population. Is this a sustainable policy? In parts of the high plains aquifer of the U.S., many landowners who have been irrigating crops for over 50 years no longer can draw water from their wells. Closer to home in Arkansas, producers are now drawing water from the Sparta aquifer, which is generally reserved for drinking water, to supplement their withdrawals from the MAA for crop irrigation. USGS groundwater modeling studies show that the water level in the MAA will continue to decline for the foreseeable future. This presentation will discuss the actions the state or producers can take to reverse the decline in the MAA. <br /><a href="http://wrri.msstate.edu/conference/pdf/johnson_david2015.pdf">Download the presentation</a>
Crop Water Use in the Mississippi Delta
Year: Authors: Kelly D.
The Yazoo Mississippi Delta Joint Water Management District (YMD) has conducted water use surveys for the past thirteen years to determine the amount of groundwater used from the Mississippi River Valley Alluvial Aquifer (MRVA). These surveys focused on cotton, soybeans, corn, rice, and catfish. Each year begins with roughly 180 sites for investigation. In an effort to determine the most efficient ways to irrigate these crops, irrigation methods for each site are recorded along with the total amount of groundwater used. Additionally, a cost analysis is performed for each site. Electric single crop wells are targeted for this study. Flow rates are obtained throughout the year. Total kilowatts from the electric meter are collected from the sites at least once each month giving YMD a total hours of well operation and cost factors. After an average amount of water per acre by crop is determined, YMD uses a Geographic Information System (GIS) to apply these estimates across the entire delta.<br /><a href="http://wrri.msstate.edu/conference/pdf/kelly_dave2015.pdf">Download the presentation</a>
Evaluation of Management Strategies to Promote Water Resource Conservation in Louisiana
Year: Authors: Adusumilli N., Davis S.
The need to safeguard water availability within Louisiana has become critical, not only to sustain the state's water resources, but also to the sustainability of sectors that depend on this important resource. Competition for surface and groundwater supplies in only increasing in the state due to many factors including demand from sectors like industry, power generation, public supply, aquaculture, increasing irrigated acreage of crops, and prolonged droughts periods. Hence, planning should be geared toward identification of strategies that ensure water availability for all reasonable present and future needs and promote conservation of water resources. Selection and/or implementation of a strategy depends on long-term objectives, economic concerns, and the willingness of the stakeholders to embrace the perspectives on water management. Thus, identification of strategies that include tools, practices, and policies that promote conservation and efficiency is critical to motivate adoption and reduce stress on aquifers, reservoirs, and other surface water sources. More specifically, the strategies should emphasize water conservation, economic incentives to conserve water, and public education. Potential benefits of improving water use efficiency include costs reductions, environmental protection, reduce losses and waste of water, and reduction in energy consumption. The strategies identified will provide planners and decision makers with the information needed toward developing a long-term statewide water management plan.
Estimation of the runoff curve number using rainfall-runoff data from agricultural systems in the Mississippi Delta and the Colombian Orinoquia.
Year: Authors: Ramirez-Avila J.J., Almansa-Manrique E., Jian Y., Ortega-Achury S.L., Laurens-Vallejo L.A.
A major activity in applied hydrology is the estimation of rainfall event runoff from ungauged small watersheds. The Natural Resources Conservation Service (NRCS) Curve Number method is used to perform different rainfall-runoff analyses for different land use and soil conditions around the world, such as the estimation of design floods for small hydraulic structures, and Best Management Practices to reduce agricultural non-point source pollution. Knowing that the calculated runoff is more sensitive to the Curve Number value than to the rainfall depth, estimation of the Curve Number values for local situations is pertinent. Observed rainfall-runoff dataset were used to estimate the Curve Number value for six different land use and tillage conditions (i.e. bare soil, pastures, conventional tillage, reduced tillage, no-tillage, crops rotation) in the Orinoquia region of Colombia and agricultural fields under reduced tillage in the Mississippi Delta region in the USA. The estimated Curve Number values for bare soil and no-tillage row crops, ranging from 61 to 72, were relatively similar than those tabulated Curve Number values determined on base of land use and soil types. Estimated Curve Number values for pastures and crop rotation (ranging from 42 to 67) were slightly higher, while for row crops under tillage practices (ranging from 72 to 81) were slightly lower than tabulated Curve Number values.
A coupled SWAT-MODFLOW model to evaluate the effects of agricultural management practices on surface and groundwater
Year: Authors: Ni X.
Water quality pollutants, which may be generated due to various agricultural activities, can affect both surface water and groundwater resources. The objective of this study is to assess the effects of agricultural management practices and climate variability on surface water and groundwater using Soil and Water Assessment Tool (SWAT) model in the Big Sunflower River Watershed (BSRW), which is major concerned by its agricultural purpose in Mississippi. In addition, the MODFLOW model, a finite-difference groundwater model, was used to simulate groundwater flow with boundary, recharge and HRUs calculated from the corresponding SWAT model. A coupled SWAT-MODFLOW model was applied to evaluate the water quality and quantity effects due to different agricultural management practices. The SWAT model was calibrated and validated by comparing monthly stream flow to observations from USGS gaging stations with both R2 and Nash-Sutcliffe model efficiency coefficient up to 0.67. Statistics increased first and then decreased with increasing hydraulic curve numbers. The model results are expected to be better after the groundwater model is coupled and calibrated with groundwater level data. Different agricultural management practices will be applied to the coupled SWAT-MODFLOW model to evaluate the effects on water quality and quantity of surface water and groundwater.
Mississippi Water Resources: Mapping the Extent of Critical and Endangered Watersheds to Assist Restoration Efforts and Conservation Planning Using NASA Earth Observations
Year: Authors: Castillo C.
Watersheds in Mississippi provide many environmental and recreational benefits to the citizens and visitors of the state. The Nature Conservancy and the Pascagoula River Audubon Center are currently working to protect coastal Mississippi watersheds, in part through urban coastal preservation initiatives. The primary objective of this project was to aid these conservation efforts by delineating watershed extents for nine coastal streams within the three coastal counties of Jackson, Hancock, and Harrison. As these are small streams (<0.5 miles - 17 miles), most do not have individual watersheds delineated in the Watershed Boundary Dataset (WBD). Specifically, three analyses were conducted: watershed delineation of the urban streams, a Land Use Land Cover (LULC) map of the three coastal counties, and a wetland extent map of a subset of that area. The individual watershed delineation was conducted through open source Geographic Information Systems (GIS) platform Quantum Geographic Information System (QGIS) with the Geographic Resources Analysis Support System (GRASS) toolbar. These were then overlaid with watershed sub-basins created in ArcGIS for comparison. Earth Resources Data Analysis Systems (ERDAS) and QGIS were also used to perform a land cover classification. The analysis of wetland areas was performed using a Maximum Entropy (MaxEnt) model. Relevant inputs to these analyses included elevation, terrain aspect, thermal data, and vegetation indices. The analyses utilized Landsat 8 Operational Land Imager (OLI) data, and stream vectors. Our results reveal the distribution of wetlands, forests, and urban areas within these watersheds. Overall, this project illustrated the utility of open data, as well as open-source software. Furthermore, these watershed and wetland maps will aid in the current conservation efforts of endangered streams in southern Mississippi.
Utilizing NASA Earth Observations to Assist the Audubon Mississippi Coastal Bird Stewardship Program with Habitat Monitoring and Restoration Planning Activities
Year: Authors: Barrett S., Beasley B., Wylie L., McDaniel B., Bosarge A.
Coastal and migratory bird habitats in Mississippi are highly dynamic and constantly threatened by human activity. Today, these coastal and migratory species can be found on managed public lands. However, as of 2014, the Pascagoula River Audubon Center (PRAC) and the National Fish and Wildlife Foundation (NFWF) reported shorebird populations in coastal Mississippi have declined. In response, the Mississippi Audubon Coastal Bird Stewardship Program (CBSP) plans to focus habitat management on approximately twenty sites in coastal Mississippi. Activities includes planning and conducting standardized monitoring, implementing best-practice restoration projects, and a campaign to educate diverse audiences to increase understanding of the threats to and environmental and societal benefits of coastal and migratory birds. To support these efforts, this NASA DEVELOP project used current Landsat 8 OLI imagery to produce habitat classification maps that incorporated land use land cover, vegetation health, and water quality indices of areas in coastal Mississippi where these vital bird habitats are located. The project yielded maps for declining coastal bird species such as the least tern. End products and methodologies aided end-users in focusing habitat restoration efforts based on individual species' propensity to a particular area.
Understanding nitrogen and organic carbon contents of agricultural drainage ditches in the Lower Mississippi Alluvial Valley
Year: Authors: Faust D.R., Kroger R., Rush S.
Agricultural fertilizer applications have resulted in excessive nitrogen loading to agricultural drainage ditches, contributing to the Gulf of Mexico hypoxic zone. The purpose of this study was to assess relationships between organic carbon and nitrogen content of drainage ditches and evaluate the spatial scope in which organic carbon amendments may be used in remediating nutrient loading throughout the Lower Mississippi Alluvial Valley. Water and sediment samples were obtained from agricultural drainage ditches in Missouri, Arkansas, Mississippi, and Louisiana. Nitrate, nitrite, ammonia, and total nitrogen concentrations were determined in overlying and pore water, along with characterizing dissolved organic carbon aromaticity (spectral absorbance at 254 nm) and molecular weight (ratio of spectral absorbance at 254:365 nm). Concentrations of ammonia and nitrate nitrogen and total organic carbon in overlying and pore waters were variable, with ranges of 0.0117 to 20.4 mg L<sup>-1</sup>, 0.05 to 17.0 mg L<sup>-1</sup>, and 0.0 to 17.0 mg L<sup>-1</sup>. However, concentrations of nitrogen species and dissolved organic carbon were generally higher in the pore water compared to those in overlying water. Pore waters generally had lower molecular weight character of dissolved organic carbon than overlying water, although this trend was dependent on the state and site from which the sample was collected. The results of this study show that there is spatial variability in nitrogen species and organic carbon throughout the Lower Mississippi Alluvial Valley and demonstrate the importance of evaluating where organic carbon may be limiting nitrogen removal in agricultural drainage ditches.
Enhancing Agricultural Water Management Through Soil Moisture Monitoring and Irrigation Scheduling
Year: Authors: Rawson J.C., Linhoss A., Tagert M.L., Sassenrath G., Kingery W.
Increasing reliance of crop producers on water for irrigation coupled with expansion of irrigated acreage has resulted in the overdraft of the Mississippi River Valley alluvial aquifer (MRVA). As water resources continue to decline, there is an immediate need for more efficient water management and greater implementation of water conservation practices. Mississippi's Natural Resource Conservation Service (NRCS) has been working with farmers to increase voluntary implementation of water conservation practices, but these systems often require financial input from the grower and take time to install and manage. The Mississippi Irrigation Scheduling Tool (MIST) uses a "checkbook" water balance calculation and offers producers a free online irrigation management tool that indicates a need for irrigation when the soil water available to the plant falls below the level needed for crop growth. The overall objective of this study has been to evaluate and refine data requirements and inputs needed to calibrate and validate of the model for testing on corn and soybean fields with differing management and soil types. Data collection has been ongoing since May of 2011. Watermark 200SS sensors and dataloggers have been used to continually measure and record soil moisture at six-inch depth increments to three feet at various sites throughout the growing season of each year. Soil water retention curves were generated for each field from detailed soil testing at each depth increment and used to convert soil tension data to actual soil water balance, which was then compared to the MIST-calculated soil water balance. In addition, comparisons were done between sets of soil moisture readings within the same field to characterize the precision of the measurements. Next Generation Radar's (Nexrad) four-kilometer precipitation data were used along with farm irrigation data to calibrate the model for a soybean field under pivot irrigation and a cornfield under furrow irrigation.<br /><a href="http://wrri.msstate.edu/conference/pdf/tagert_ML2015.pdf">Download the presentation</a>
The Benefits and Potential for Well Fields in the Mississippi Delta
Year: Authors: Bowling T., Janes L., Pennington D.
Over the last 30 years, withdrawals from the Mississippi River Valley Alluvial Aquifer (MRVA) have exceeded the aquifers natural ability to recharge resulting in a significant decline in the groundwater table in the Mississippi Delta. As water levels in the aquifer begin to drop, the dry season stream flows also begin to decline because less water is flowing from the aquifer into the streams. The portion of the aquifer underlying lands in close proximity to the Mississippi River are influenced by the fluctuations of water levels of the river system. During high and normal river stages, the Mississippi River can assist recharge of the groundwater aquifer near the river. During low river stages, groundwater from the aquifer can actually be lost by flowing back into the river. The Yazoo Mississippi Delta Joint Water Management District (YMD) has implemented and operated a working well field near Friar's Point, MS to better utilize Mississippi River recharged groundwater. Since 2005 YMD has used Mississippi River influenced groundwater to augment flows in the Sunflower River. Groundwater is extracted from a series of 11 wells and discharged into a tributary of Swan Lake. Water then flows through a water control structure at the Swan Lake outlet into a series of tributaries before joining the Sunflower River north of Clarksdale, MS. Pumps are operated in order to maintain a 50 cubic foot per second flow rate at the Sunflower, MS river gauge. Since 2012, YMD has monitored wells along the Mississippi River to develop a dataset in order to determine the extent of the Mississippi River's influence on the MRVA. By installing extraction wells in areas where the Mississippi River is in direct contact with the MRVA, well fields have the potential to capture clean, filtered Mississippi River water without adversely affecting the MRVA. Captured Mississippi River water can then be conveyed inland to aid in times of low flow to assist aquatic ecosystems and provide an abundance of surface water irrigation opportunities for the Mississippi Delta.<br /><a href="http://wrri.msstate.edu/conference/pdf/bowling_taylor2015.pdf">Download the presentation</a>
Pecan Bayou: A Pilot-Scale Comprehensive Conservation Watershed Proposal
Year: Authors: Janes L., Bowling T., Pennington D.
Over the last 30 years, withdrawals from the Mississippi River Valley Alluvial Aquifer (MRVA) have exceeded the aquifers natural ability to recharge resulting in a significant decline in the groundwater table in the Mississippi Delta. In an effort to decrease the overdraft of the MRVA, the Yazoo Mississippi Delta Joint Water Management District (YMD) has proposed implementing the Pecan Bayou Comprehensive Conservation Watershed to develop new water sources for irrigation water supply coupled with utilization of available conservation and management practices. Pecan Bayou is also a pilot planning component of a feasibility study with the USACE to import water into the Quiver River to enhance aquatic habitat and provide surface water for irrigation. This project has the potential to convert approximately 3000-5000 acres from groundwater to surface water irrigation and potentially offset the calculated overdraft within the project footprint. The project would consist of a re-lift station on the Quiver River to import approximately twenty-five (25) cubic feet per second (cfs) of surface water into the system for irrigation purposes. Imported surface water will be distributed through a network of improved natural channels and constructed zero-grade, lateral ditches. Weirs and water control structures will be constructed to divert and retain water in the system. The excavated channels and water control structures will not only provide water distribution and storage but also provide runoff recovery, improved drainage, and water retention. YMD also plans to implement available conservation practices, per landowner approval, to maximize the benefits of the system. YMD envisions the Pecan Bayou Comprehensive Conservation Watershed becoming a pilot-watershed to act as a blue-print for managing the natural resources of the Mississippi Delta.<br /><a href="http://wrri.msstate.edu/conference/pdf/janes_leighton2015.pdf">Download the presentation</a>
Pathogen Indicator Monitoring in the Ross Barnett Reservoir
Year: Authors: Capps P., Surbeck C.
Man-made reservoirs are often used for both water supply and recreation. The Ross Barnett Reservoir in central Mississippi, a 33,000-acre man-made lake, provides drinking water to the city of Jackson, MS, and forty-eight surrounding communities. Further, an estimated 2.5 million people visit the reservoir each year for recreational purposes, including boating, fishing, water-skiing, and swimming. Protecting the water quality in the reservoir is important for these visitors and inhabitants along the shoreline, and for these reasons, the U.S. Environmental Protection Agency has selected it as a Priority Watershed in Mississippi. Presently, there is a concern regarding recent data collected that indicated increasing concentrations of bacteria in the Ross Barnett Reservoir. To detect possible harmful levels of bacteria in recreational waters, pathogen indicator monitoring is used. Sources of pathogens may include stormwater runoff, failing septic systems, lake-bottom sediments, and animals and humans in direct contact with the water. A collaborative study to investigate potential pathogen contamination in the reservoir is underway by the University of Mississippi, the U.S. Geological Survey, and the Mississippi Department of Environmental Quality. The goal of the study is to determine a method of pathogen indicator monitoring that takes less time than the standard 24 hours required by current methods for detecting bacteria. Such a method would improve the swiftness of notification to reservoir users when the water quality is not appropriate for contact. Pathogen indicators and other water-quality data such as water temperature, pH, turbidity, conductivity, dissolved oxygen, nutrients and solar strength, were collected at two recreational sites at the reservoir twice a week for 23 events through the spring and summer of 2013 as part of the collaborative study. Average concentrations for all E. coli, enterococci, and fecal coliform were 264 cfu/100mL, 175 cfu/100mL, and 298 cfu/100mL, respectively. The concentrations of pathogen indicators, nutrients, and values of physical parameters were statistically analyzed to provide insight about contamination sources. This research indicated that two water quality indicators of harmful bacteria levels in the water were turbidity at sites with low water circulation and days following rain events.
Water Quality Changes in On-Farm Water Storage Systems: A Seasonal Variability Analysis
Year: Authors: Pérez-Gutiérrez J.D., Paz J.O., Tagert M.L.
Agricultural practices adversely alter the nutrients' natural cycle. The changes are due in large part to the dramatic increase in the use of fertilizers to support agricultural production. A substantial portion of nutrients is transported to groundwater and adjacent waterbodies via surface and irrigation runoff. This environmental issue is of special concern in the Mississippi River Basin, as it is the main source of nutrients that stimulate the development of the hypoxia zone in the northern Gulf of Mexico. To address this issue, Best Management Practices (BMPs) have been implemented with the aim of reducing nutrient loading from agricultural lands in the Mississippi Delta region. Recently, On-Farm Water Storage (OFWS) systems have attracted much attention because of their benefits to the environment, farmers and landowners. However, little is known about the watershed-scale impacts of these systems, as well as the effectiveness of OFWS systems in reducing nutrient loading downstream. This study discusses water quality changes in OFWS systems by analyzing the seasonal variability of several water quality parameters collected from OFWS systems at two farms in Porter Bayou watershed, Mississippi. Preliminary results reveal considerable differences in nitrogen and phosphorus concentrations between the influent and effluent water samples. The OFWS systems examined in this study show significant nutrient loading reduction downstream.
Planning the future with an eye to the past: Land Use and Water Quality on the Mississippi-Alabama coast
Year: Authors: Carmichael R.H., Darrow E., Wu W., Huang H., Calci W., Burkhardt W., Walton W., Pasch A.
We conducted a 4-year study to measure land-use related nutrient source and pathogen indicator changes through time using Grand Bay, on the Mississippi-Alabama coast, as a benchmark system. The study determined how land use changes in the past have affected water quality, natural resources, and potentially human health to provide data for local land use planning and decision-making. Data showed that historical and present-day land use, particularly increased wastewater and stormwater inputs to coastal areas, has affected water quality and potential for shellfish harvest. Of the five sites tested in the Grand Bay area, Bayou Chico in Mississippi was identified as having particularly poor water quality. Wastewater treatment was demonstrated as a method to reduce water quality impairment throughout the area. On August 1, more than 40 researchers, managers and members of the public met for a one-day workshop at the Grand Bay National Estuarine Research Reserve to discuss these findings and recommend data products to guide water quality improvements on the Mississippi-Alabama coast. Stakeholders identified two products as potentially most useful to promote water quality protection: a quantitative tool to predict how future land use change will affect water quality (nutrients and pathogens) and educational materials to raise awareness among local citizen groups, from eco-tourists to municipal officials. While full implementation of these products will take time, this workshop demonstrated that communication with stakeholders was useful to guide application of scientific data. To sustain water quality and shellfisheries safe for harvest, communities will need to balance land use, particularly area of impervious surface, with suitably designed wastewater treatment alternatives (e.g.; for runoff or combined sewage overflows) and water quality outcomes appropriate for natural resource and public health protection.
Evaluating analytic and risk assessment tools in agricultural fields of Mississippi
Year: Authors: Ramirez-Avila J., Oldham J.L., Ortega-Achury S.L., Gallardo-Estrella R., Baker B., Alexander K., Locke M., Read J.J.
Nutrient and sediment runoff from agricultural fields is a critical problem associated with impairment of waterbodies in Mississippi and has generated a need to identify best nutrient management practices that minimize sediment and nutrient losses from fields, mitigating their contribution to a low-oxygen environment in the Gulf of Mexico. Environmentally safe and cost-effective implementation of quantified nutrient load reductions would require analysis of site-specific monitored water quality data that help producers to identify the most appropriate conservation practices for protecting or improving water quality. But lack of information in many regions regarding edge of the field and watershed monitoring for water quality and quantity and their associated costs, has promoted the use of qualitative and quantitative risk assessment models or tools to explore actions and policy alternatives for managing both water quality and quantity from intensive agricultural fields. National, regional and State nutrient reduction initiatives have indicated that the evaluation and selection of analytical tools (or risk assessment models) needs to be included as one of the strategies for designing, siting and assessing potential reductions from multiple management practices implemented within the Mississippi Delta, and subsequently, the Mississippi Upland and Mississippi Coastal regions. A Conservation Innovation Grant (CIG) project is being conducted to determine the existent need to assess and enhance the ability of existing risk assessment tools for improved cost-effectiveness of conservation practices, and enhance stakeholder's ability to make appropriate resource conservation decisions supported through such tools. This project supports specifications in the recently revised USDA-NRCS nutrient management standard (590) and state nutrient criteria. Preliminary results are presented on research to test and validate five quantitative (APEX, NTT, APLE, N-Index, and RUSLE2) and three qualitative (P-Index, N Leaching Index, WQ Index) risk assessment tools in fields from the Mississippi Delta and the poultry production area in South Mississippi.<br /><a href="http://wrri.msstate.edu/conference/pdf/oldham_larry2015.pdf">Download the presentation</a>
Assessment of On-Farm Water Storage System (OFWS) for design and nutrient variability in the Mississippi Delta and East Mississippi
Year: Authors: Karki R., Tagert M., Paz J.
Irrigation can help increase crop yields, decrease risk, and provides an avenue for crop diversification in Mississippi. In the Mississippi Delta, where groundwater is the primary source of water for irrigation, the Mississippi River Valley alluvial aquifer is being mined at an average of 3,00,000 acre-feet per year and the amount of withdrawal exceeds the recharge rate leading to a reduction in groundwater levels. Nutrient loading from irrigation tail water is another major concern in the Mississippi Delta. It has been estimated that about 1.5 million metric tons of nitrogen are being transported to the Gulf of Mexico every year from the Mississippi River Basin resulting in eutrophic conditions that has led to the development of hypoxic zones. An On-Farm Water Storage (OFWS) system, which consists of a tail water recovery ditch and a water storage pond, is a constructed BMP that has a primary goal of water conservation by capturing surface runoff from excess rainfall and irrigation tail water. This paper will describe an OFWS design and discuss the differences in OFWS establishment in the Mississippi Delta and East Mississippi based on irrigation techniques and tail water recovery systems. Preliminary findings on the difference in nutrient content of the storm water runoff and storage pond will also be discussed.<br /><a href="http://wrri.msstate.edu/conference/pdf/karki_ritesh2015.pdf">Download the presentation</a>
Water Resource Planning and Solution Implementation in the Mississippi Delta: YMD Joint Water Management District
Year: Authors: Pennington D.
The YMD Joint Water Management District was created in 1989 to develop and implement solutions to many of the Delta's water supply and quality problems. Heavy use of groundwater by agriculture has resulted in declining groundwater levels which are not sustainable and also contribute to loss of stream base flows. YMD has always recognized that efficient use of existing water supplies (conservation) and the development of new water supplies were the only non-regulatory solutions available to address the Delta's water supply problems. A simple spreadsheet model has been developed to provide 50 year scenario analysis of different conservation and water supply plans. The primary variables of the model are levels of conservation implementation, new water supplies and irrigation expansion. Results of the model indicate that, individually, conservation or new water supply will not have sufficient capacity to create a balanced water budget in the Delta. Both conservation and new water supplies will be needed if we continue to expand irrigated acres at historic rates. Following presentations in the session will go into greater detail about some of YMD's major efforts to collect water resources information to support planning efforts and our activities related to on-the-ground solutions.
Assessment of tailwater recovery system and on-farm storage reservoir efficacies: Quantity issues
Year: Authors: Czarnecki J.M., Omer A.R.
In the State of Mississippi, the USDA via the Natural Resource Conservation Service has provided financial assistance for ~200 tailwater recovery systems (TWR) with and without the addition of an on-farm storage reservoir (OFS); over half of these systems are located within Sunflower County, overlying the cone of depression. The objective of this study was to quantify capture and use of TWR (and OFS, where available). In order to understand the water quantity benefits of TWR and OFS, it was necessary first to determine how much water these systems captured over the course of the year and how much water was lost from these systems due to natural processes. Working with agency partners, a list of TWR and OFS was compiled and 30 sites (18 TWR/12 OFS) were selected for study. Each site was instrumented with a water level logger. Loggers were set to capture data at 15-minute intervals. Loggers were deployed for at least a year in most systems. Dimensions and build specifications for each system were obtained to convert depth measurements into volumes. Incremental changes in volume and surface area were calculated for the span of the data collection effort. Considerations for evaporation and infiltration were made using best available models and methods to quantify these losses. These resultant values can then be weighed against the potential levels of capture, re-use, and loss, and the conservation contribution of TWR and OFS can be quantified. It is intended that these values will provide insight for agency personnel to determine if the benefit justifies the cost relative to other, alternative best management practices.
Groundwater Levels in the Mississippi River Valley Alluvial Aquifer
Year: Authors: Stiles M.
The Yazoo Mississippi Delta Joint Water Management District (YMD) collects water level information from the Mississippi River Valley Alluvial Aquifer (MRVA) twice each year, once in April and again in October. These months are used to allow staff to obtain water levels before and after the groundwater irrigation season. Measurements are gathered from a network of 550 survey wells located throughout the entire Mississippi delta. Tablet computers configured with custom software are used by field staff to assist with data entry and quality control. The information gathered from each water level survey is incorporated into the YMD geographic information system (GIS). After the field work is completed for each water level survey, YMD uses GIS to create water level surface maps. These surface maps serve as the primary datasets used by YMD to create short and long term aquifer water level change maps. Additionally, GIS is used to create aquifer water volume changes. These changes are calculated annually from Spring to Spring and Fall to Fall. Additional changes are calculated for fall to spring representing aquifer recovery and spring to fall representing water withdrawals. The aquifer water volume changes are calculated then entered into a spreadsheet for graphing. <br /><a href="http://wrri.msstate.edu/conference/pdf/stiles_mark2015.pdf">Download the presentation</a>
Evaluation of Input Variables for Neural Network Models used in Groundwater Level Forecasting for Sunflower County, Mississippi
Year: Authors: Guzman S., Paz J., Tagert M.
Declining water levels in the Mississippi River Alluvial Aquifer (MRVA) are due to the expansion of irrigated acreage and increasing water demand in the Mississippi Delta region, causing the need to develop forecasting tools and improve conservation measures. One of the tools explored in recent investigations is the Artificial Neural Network (ANN) that has grown in popularity in terms of its application in modeling and forecasting nonlinear hydrologic time series such as groundwater levels. For instance, a previous study demonstrated that an ANN with 2 hidden layers, 100 time delays and Bayesian Regularization training algorithm had the best model architecture that provided predictions of daily groundwater levels up to three months ahead. The effectiveness of ANN in forecasting daily groundwater levels depends on different input datasets as well as on the network learning capacity. An important step in the ANN development process is the evaluation of significant input variables, given that not all of them are powerful predictors of the model output. In this study, the performance of an ANN trained with a Bayesian Regularization algorithm and different input variable combinations was evaluated to determine the optimal model that can simulate groundwater trends up to three months in a USGS monitoring well located in Sunflower County, Mississippi. Nine years of daily groundwater level measurements were collected and partitioned into training and validation data sets. At the same time, input time series such as daily evapotranspiration rates, calculated by the Priestly-Taylor method, and daily precipitation were also partitioned into training and validation sets. The evaluation of the model performance under different input variables was based on the Mean Square Error (MSE) and correlation statistic estimations. The use of ANN with significant input variables provides useful information for the management of water withdrawals either per well or on a regional level in order to implement different conservation practices.
A Multivariate Evaluation of the Saline Groundwaters within Parts of the Middle Benue Trough, Nigeria.
Year: Authors: Abu N.
Structural interpretation of aeromagnetic data and Landsat imagery over the Middle Benue Trough was carried out to determine the depth to basement, delineate the basement morphology and relief, and the structural features within the basin. The aeromagnetic and Landsat data were subjected to various image and data enhancement and transformation routines. Results of the study revealed lineaments with trend directions in the N-S, NE-SW, NW-SE and E-W directions, with the NE-SW trends been dominant. The depth to basement within the study area was established at 1.8Km, as shown from the spectral analysis plot. The Source Parameter Imaging (SPI) plot generated showed the central-south/eastern portion of the study area as being deeper in contrast to the western-south-west portion. The basin morphology of the trough was interpreted as having parallel sets of micro-basins which could be considered as grabens and horsts in agreement with the general features interpreted by early workers. Major elements used as hydrological tracers (Na, K, Mg, Ca, Fe, S, P, Al) and trace elements (Co, Sr, Ba, Cr, Mo, Mn, B, Zn, Pb, Si, I) were analyzed from the groundwaters within the study area. Piper'sTrilinear diagram was used for the classification of the groundwater within the study area as Mg-Na-H<sub>2</sub>CO<sub>4</sub> waters, SO<sub>4</sub>-Cl-HCO<sub>3</sub> waters and HCO<sub>3</sub>-Cl waters. Hydrogeochemical characteristics of the saline groundwaters were evaluated by means of physico-chemical analysis on the collected samples. Conventional graphical plots, principal component analysis and geochemical modelling techniques were applied to evaluate the geochemistry of the brines. The principal components extracted on the data matrix explained 100% of the total variance. The first PC explained 69.87% of the variance and accounted for the majority of the variance in the original data set. It is mainly participated by (Tempt, TDS, Ca, Fe, Mg, Na, P, Sr, Cl, Br and SO<sub>4</sub>). The second PC is characterized by (eH, P and H<sub>2</sub>CO<sub>3</sub>) and accounted for 19.66% of the variance. The third PC, which accounted for 10.47% is participated by (pH, Sr, F, and P). A direct hydrochemical comparison of the analyzed saline water samples with standard seawater evaporation trajectory was used in the interpretation of the Bromide-chloride relationship, which showed a linear correlation, indicating that these waters might have originated from seawater that did not evaporate to the point of halite precipitation, consistent with the absence of any type of evaporite deposit in the trough. By combining the observed isotopic characteristics and the elemental analyses of the the groundwaters presented in this study, the origin of the brine/salt could be said to be marine, related to the embedded fossil seawater within the transgressive marine sediments (Asu River Formation and Eze-Aku shales), on one hand, and to the disseminated/precipitated salts within the regressive (sandstone/siltstone) interbeds of the Awe Formation, on the other hand. The up-flux movement of the groundwaters, in addition to surface meteoric input, is suggested to be the possible hydraulic process responsible for the dissolution and or leaching of disseminated salts, as well as the modification and remobilization of the embedded fossil seawater within the underlying sedimentary units.
Design and implementation of a groundwater-streamgage network to assess groundwater and surface water interaction in the Mississippi Delta
Year: Authors: Roberts B.A., Barlow J.R.
In 2014, the U.S. Geological Survey (USGS), Mississippi Water Science Center, in cooperation with the U.S. Army Corp of Engineers, Vicksburg District, installed and instrumented a total of ten groundwater-streamgages throughout the Yazoo Basin. Each groundwater-streamgage collects and transmits, at minimum, stream stage, stream temperature, groundwater level, and groundwater temperature. Site instrumentation consisted of installing near-stream piezometers near existing or new streamgages. These piezometers house pressure transducers with temperature recorders and provide a means to measure and record periodic water-levels in order to check the continuous data from the logger. Each groundwater-streamgage is operated and maintained on a regular schedule (approx. 8 week interval), and all data are transmitted real-time to a project web page. Groundwater-streamgages provide a framework to document the spatiotemporal variability of groundwater and surface-water interaction. Data will be used to better understand the potential connectivity between the stream and the alluvial aquifer within the Yazoo River Basin and how connectivity affects water quantity and quality throughout both. This network will also help understand and quantify the extent that the interaction between streams and the alluvial aquifer has been affected by declining water levels in the alluvial aquifer.
Mississippi Water Resources: Mapping the Extent of Critical and Endangered Watersheds to Assist Restoration Efforts and Conservation Planning Using NASA Earth Observations
Year: Authors: Castillo C., Crepps G.
Watersheds in Mississippi provide many environmental and recreational benefits to the citizens and visitors of the state. The Nature Conservancy and the Pascagoula River Audubon Center are currently working to protect coastal Mississippi watersheds, in part through urban coastal preservation initiatives. The primary objective of this project was to aid these conservation efforts by delineating watershed extents for nine coastal streams within the three coastal counties of Jackson, Hancock, and Harrison. As these are small streams (<0.5 miles - 17 miles), most do not have individual watersheds delineated in the Watershed Boundary Dataset (WBD). Specifically, three analyses were conducted: watershed delineation of the urban streams, a Land Use Land Cover (LULC) map of the three coastal counties, and a wetland extent map of a subset of that area. The individual watershed delineation was conducted through open source Geographic Information Systems (GIS) platform Quantum Geographic Information System (QGIS) with the Geographic Resources Analysis Support System (GRASS) toolbar. These were then overlaid with watershed sub-basins created in ArcGIS for comparison. Earth Resources Data Analysis Systems (ERDAS) and QGIS were also used to perform a land cover classification. The analysis of wetland areas was performed using a Maximum Entropy (MaxEnt) model. Relevant inputs to these analyses included elevation, terrain aspect, thermal data, and vegetation indices. The analyses utilized Landsat 8 Operational Land Imager (OLI) data, and stream vectors. Our results reveal the distribution of wetlands, forests, and urban areas within these watersheds. Overall, this project illustrated the utility of open data, as well as open-source software. Furthermore, these watershed and wetland maps will aid in the current conservation efforts of endangered streams in southern Mississippi.
Factors influencing primary production and respiration in Grand Bay National Estuarine Research Reserve
Year: Authors: Caffrey J.M., Amacker K.S., Murrell M.C., Woodrey M.
Advances in technology have greatly increased our ability to collect water quality data over a variety of space and time scales. For example, commercially available data sondes deployed to collect time series of temperature, salinity and dissolved oxygen data can capture events from hourly (tidal and diurnal) time scales to seasonal time scales capturing freshwater runoff and algal blooms. Analysis of data from these long-term deployments provides insights into the relative importance of anthropogenic and external drivers on estuarine ecosystem function. Dissolved oxygen time series have been used to estimate daily gross production, respiration and net ecosystem metabolism (NEM). However, long-term estimates of primary production and ecosystem respiration are rare in the estuarine literature, yet they provide fundamental information about the trophic status of these sensitive environments. When collected consistently, this approach makes it possible to resolve long-term trends, but perhaps more importantly, it provides a historical benchmark against which future patterns may be evaluated. Grand Bay National Estuarine Research Reserve is a small and relatively pristine estuary in the northern Gulf of Mexico. Freshwater input into the estuary is primarily local runoff from bayous and tidal creeks, including Bayou Cumbest, Bayou Heron, and Bangs Lake Nutrient loading to Grand Bay is relatively small, with ambient nutrient concentrations often below detection. Primary production was calculated from diurnal dissolved oxygen data sonde data using Odum's open water method. Primary production and respiration was highest in the summer and rates of these processes were highly correlated. Despite interannual patterns in freshwater flow and salinity, variability in metabolic rates was low, perhaps reflecting shifts in the relative importance of benthic and phytoplankton productivity, during different flow regimes. Primary production and water column chlorophyll a in Grand Bay following a 2005 phosphorus spill was similar that from other years. The lack of stimulation by phosphorus is consistent with nutrient addition bioassay experiments performed at Bangs Lake and Point aux Chenes. Samples collected bimonthly showed that nitrogen rather than phosphorus stimulated phytoplankton growth at both locations.
Water Quality in Bangs Lake: effects of recurrent phosphate spills to a coastal estuary
Year: Authors: Dillon K., Caffrey J., Carmichael R., Holcomb S., Griffin C., Allen J., Jones T., Price K.
Bangs Lake, an estuarine water body in the Grand Bay NERR, has been the site of three industrial phosphate spills from a nearby fertilizer plant since 2005. Due to restricted tidal exchange in Bangs Lake, these events have had long lasting effects on water column phosphate concentrations which may stimulate biological activity and alter the biogeochemical cycling of essential elements within the water column and the sediments. To determine the fate of excess phosphate from the industrial spills, we measured soluble reactive phosphate concentrations in sediment pore water and total particulate phosphate concentrations from sediment cores (0-25 cm depth) from four locations: North Bangs Lake (closest to spill locations), Bangs Lake, and two low impact reference sites (Bayou Cumbest and Bayou Heron). We also conducted phosphate adsorption experiments and measured benthic chlorophyll concentrations with sediments from these sites to determine if the excess PO4 was fertilizing benthic microalgae to determine the fate of this excess PO4. Pore water phosphate concentrations were highest (21 uM) from 10 to 20 cm depths in North Bangs Lake cores however pore water from the surface sections of these cores had much lower phosphate concentrations (<0.5 uM). Pore water from the Bangs Lake cores consistently had elevated phosphate concentrations (2 to 5 uM) throughout the core length while pore water phosphate concentrations from one reference site were much lower (<0.7 uM), likely reflecting background levels. Phosphate adsorption experiments show that surface sediments from North Bangs Lake and Bayou Cumbest rapidly stripped phosphate from solution to final concentrations of <3 uM while surface sediments from Bangs Lake had greatly reduced phosphate adsorption capacity with much higher final concentrations (24 to 32 uM) indicating these sediments are near saturation. In 2013 and 2014, Sediment chlorophyll a concentrations were higher in Bangs Lake compared to the reference site. Sediment chlorophyll a was significantly correlated with extractable phosphate concentration in sediments (r = 0.88). In addition, grow out experiments with amendments of phosphorus to water and sediment samples stimulated the growth of cyanobacteria capable of fixing nitrogen.
USDA-ARS Long-term Agroecosystem Research Network: A new initiative for long-term monitoring, research, and collaboration in the Lower Mississippi Riv
Year: Authors: Rigby J.R., Locke M.A.
The Lower Mississippi River Basin is one of the most productive agricultural regions in the country links agricultural practices and associated runoff and nutrient loads from the Upper Mississippi, Missouri, and Ohio basins with the ecology of the Gulf of Mexico. In 2013 the USDA-ARS founded the Long-term Agroecosystem Research (LTAR) network consisting of 18 member locations across the United States to address long-term research and monitoring goals for U.S. agriculture. The Lower Mississippi River Basin (LMRB) is a member location of the network administered by the USDA-ARS National Sedimentation Laboratory. The LTAR network will focus activity on development of agroecosystem observatories with common standards for cross-site monitoring at all locations as well as a set of experiments to address the long-term sustainability of agriculture and the broader agricultural landscape in the U.S. A number of sustainability challenges face the Lower Mississippi River Basin including increased concerns around water quantity and quality issues.<br /><a href="http://wrri.msstate.edu/conference/pdf/rigby_jr2015.pdf">Download the presentation</a>
Soil Water Monitoring Using Wireless Sensor Network
Year: Authors: Sui R.
Mississippi Delta is one of the most productive and intensively irrigated agricultural regions in US. Although there is more than 1000 mm of annual precipitation in this region, uncertainty in the amount and timing of precipitation is one of the most serious risks to the producers. Producers in this region have become increasingly reliant on supplemental irrigation to ensure adequate yields. There are more than 17,000 water wells in Mississippi Delta used to pump groundwater from the Mississippi River Valley Alluvial Aquifer for agricultural irrigation. Increasing groundwater withdrawal is resulting in a decline in the aquifer levels. It is necessary to develop improved water management tools for water resource preservation and sustainable agriculture in this region. To increase water use efficiency and productivity, novel sensing technologies are required to determine crop water status and conduct irrigation scheduling. Crop water status and the amount of supplementary water needed can be assessed by measuring soil moisture and plant physical response to water stress. A wireless sensor network (WSN) was built and deployed in three fields to monitor soil moisture status and collect weather data for irrigation scheduling. The WSN consists of soil moisture sensors, weather sensors, wireless data loggers, and a wireless modem. Soil moisture sensors were installed at three depths below the ground surface in various locations across the fields. Weather sensors were mounted on a 3-m instrument tower. An antenna mount was designed and fabricated for use in the WSN. When field equipment such as a fertilizer or chemical applicator impacted the mount, the mount was capable of protecting the antenna from damage by the equipment. The WSN has been deployed and operated in fields with cotton, corn, and soybean crops for three years. It performed well in data collection and transmission. No major operational issues occurred with the WSN except occasional data transmission interruptions by the thunderstorms during the summer. Using the WSN system, soil moisture and weather conditions including precipitation, solar radiation, wind speed, and humidity were measured every minute and the hourly averages were reported and stored at one-hour interval. The soil moisture data and weather data were automatically and wirelessly transmitted to the internet making the data available online. Data collected by the WSN have been used in irrigation scheduling research in cotton, corn and soybean crops.<br /><a href="http://wrri.msstate.edu/conference/pdf/sui_ruixiu2015.pdf">Download the presentation</a>
Tillage and Cover Crop Effects on Runoff Water and Soil Quality
Year: Authors: Locke M.A., Krutz J., Steinriede W., Dabney S.
Conservation management systems need to be assessed in the lower Mississippi River alluvial basin to balance production goals with environmental concerns. Complementary approaches for assessing effects of tillage and cover crops on water and soil quality in cotton (<i>Gossypium hirsutum</i> L.) production are reviewed here. In Study 1, no-tillage (NT) or minimum tillage (MT) with or without cover crop (rye [<i>Secale cereale</i>], balansa clover [<i>Trifolium michelianum ssp. Balansae</i>], or none) treatments were assessed from 2001 to 2006 for changes in soil characteristics and production. In 2007, a rainfall simulation study was conducted to evaluate treatment effects on runoff. In Study 2, NT, MT, MT with rye cover, and conventional tillage (CT) were assessed for effects on soil changes (2003 to 2011) and runoff water quality (2007 to 2011). Synthesis of results from these studies indicated that: (a) Cover crop and reduced tillage resulted in modest increases in soil organic matter and soil nitrogen; (b) Soil biological activity was enhanced by cover crops (e.g., enzymes, mycorrhizae); (c) Total runoff sediment loss was reduced by no-tillage and cover crop; (d) Nitrogen and phosphorus associated with runoff sediment were reduced in no-tillage and cover crop; (e) Soluble nitrogen and phosphorus in runoff was variable, sometimes higher in no-tillage and cover crop plots.
Policy Considerations for the Restoration of Mississippi's Rivers, future Water Quality, and Environmental Management with Consideration for the Futur
Year: Authors: Appleton J.
Considering the projects that are the result of the Gulf Coast Restoration Act (GCRA), continued and on-going concerns with regards to water quality, agricultural and forestry activities, and the predicted impact of future warming on the rivers and streams of Mississippi, policy makers should consider a broad agenda of not simply providing water for future use and need, but these projects as the foundation of a new approach to the management of the states flowing water resources. These streams and rivers should not merely be considered for restoration, but for on-going mitigating management and development. In essence, in the context of warming temperatures, these resources are not and cannot be restored in the narrow sense, but can be managed in the dynamic sense. Such management should not be limited to, but could include wider civic participation in both the managerial goal setting, and in the care of the rivers and streams themselves. The rivers and steams should be evaluated with consideration for their ecosystems services, mitigation of the effects of a warming climate, and as the backbones of green corridors. Consideration should not include just the water itself, but the riparian ecology, the watershed, the management and perhaps the expansion and/or reintroduction of a range of species. The overall goal of future policies should be the provisioning and protection of water resources as part of a larger effort of environmental protection, and warming mitigation and adaptation.
Analysis and Prediction of Water Deficit for Soybean, Corn and Cotton in the State of Mississippi
Year: Authors: Feng G.
Supplemental irrigation are becoming common practice in Mississippi to stabilize and increase crop productivity and quality after crop late vegetative growing season. Agriculture consumes 90% of consumptive water use, 80% is from groundwater, only 20% is from surface water in the US second largest annual rainfall state of Mississippi. In western Mississippi, groundwater levels are declining due to increasing groundwater withdrawal for irrigation. Mississippi Delta will face a serious shortage of water for agriculture. In eastern Mississippi, the groundwater is so deep and expensive to pump for irrigation, majority of growers choose using surface pond water for irrigation. Sustainable conjunctive use of surface and ground water resources for irrigation requires knowledge of crop water requirements and deficit (difference in precipitation and evapotranspiration). Therefore, water deficit of dominant irrigated crops, soybean, corn and cotton in Mississippi western Delta and eastern Blackland Prairie regions was estimated. Historical weather data in the two regions dating back to 1800 were analyzed using time series statistical models. The patterns of changes in air temperature and precipitation in the past and future were determined. The obtained trends and other results will help understand climate change and provide agroecosystem models with information to assess agriculture sustainability and competitiveness as affected by such climate change in the future. Water requirements of the three major crops in the two regions were calculated using Hargreaves method. Spatial and temporal probability distribution and frequency of water deficit in both Delta and Blackland Prairie were analyzed. As a result, we are able to forecast water deficit of each individual crop during every growing stage in the state of Mississippi for irrigation scheduling, drainage design, rainfall harvest planning, and agronomic management practice development to make most use of both ground and surface water resources.
Evaluating the impacts of crop rotations on groundwater storage and recharge in the Mississippi Delta
Year: Authors: Dakhlalla A.O., Parajuli P.B.
The Mississippi River Valley Alluvial Aquifer, which underlies the Big Sunflower River Watershed (BSRW), is the most heavily used aquifer in the state of Mississippi. Because the aquifer is primarily used for irrigating crops such as corn, cotton, soybean, and rice, the water levels have been declining rapidly over the past few decades. The objectives of this study are to (1) develop a calibrated and validated model using SWAT for streamflow and water table depths in the BSRW, (2) analyze the relationship and trends between evapotranspiration and groundwater recharge rates within the model, and (3) to model the effects of various crop rotation strategies on groundwater storage and recharge. The model performed well during the calibration periodR<sup>2</sup>= 0.53 to 0.68 and NSE = 0.49 to 0.66) and validation perio(R<sup>2</sup>= 0.55 to 0.75 and NSE = 0.49 to 0.72) for daily streamflow, which was achieved by the SUFI-2 auto-calibration algorithm in the SWAT-CUP package. The model also performed well in simulating seasonal water table depth fluctuations at the calibration sub-basin (R<sup>2</sup> = 0.58 and NSE = 0.56) and at the validation sub-basin (R<sup>2</sup> = 0.72 and NSE = 0.63). The crop rotation scenarios with rice planting resulted in the lowest groundwater storage (-8.3% to -9.6%) compared to the baseline crop scenario, which is due to the high irrigation rates of the rice crop. However, the rice crop rotations resulted in the highest increases of groundwater recharge rates (+19.4% to +59.5%), likely because of the response to the deficiency of groundwater needed for irrigation as well as the limited water uptake by the shallow rice plant roots. The crop rotations with corn and cotton resulted in the largest increases in groundwater storage (+9.6% to +26.7%), which is the result of the low irrigation rates as well as the short time period between planting and harvesting. The results of this study is expected to aid farmers and watershed managers to conserve groundwater resources, but still maintain crop production.
Water and Environmental Science Programs for Underrepresented Communities in Mississippi
Year: Authors: Diaz J.
The goal of this presentation is show current water and environmental science programs developed at Alcorn State University. Alcorn State University - ASU, a Land Grant and Historically Black University located in southwest Mississippi, offers a Bachelor of Science in Agricultural Sciences with emphasis in Environmental Science. This program prepares highly skilled individuals for lifelong environmental career in private and public organizations. Students are trained to understand, investigate, and manage the environment and the many interactions among physical, chemical, biological, economical, and societal components towards a sustainable society. The program consists of 21% social science courses, 24% basic science classes, and 55% applied science subjects. Applied environmental classes include: water quality, concepts of environmental science, geographical information systems applications in natural resources, watershed hydrology, agricultural and environmental law. ASU's Mississippi River Research Center - MRRC is actively involved in mentoring and outreach activities which support the MRRC's mission in reaching out to students and general community as well as training the next generation of minority professionals in science and applied technology areas. Since January 2013, staff and students from the MRRC have prepared and performed eight outreach activities reaching about 200 school students. Through a National Science Foundation grant, the MRRC developed an environmental science activity manual and trained 16 middle-school teachers by providing content and hands on activities in three major themes: water, erosion, and environmental consciousness. Major accomplishments in student involvement include mentoring eight students; hosting two undergraduate students from Oberlin College, OH and University of Florida, FL through the NOAA-NGI Diversity Internship Summer Program; attending six professional meetings; and reaching third place in graduate poster competition in the 71st professional Agricultural Workers in Tuskegee University, Alabama. Currently, the MRRC is leading five projects funded by the State of Mississippi, US Department of Agriculture, US Forest Service, and Monsanto. Projects are focused on evaluating the temporal and spatial water quality variation and the indication of total coliform bacteria and Escherichia coli in four small lakes at ASU; assessing climate change impacts on southern Mississippi watersheds; measuring the acid neutralizing capacity of forest and aquatic ecosystems in Louisiana and Mississippi national forests; understanding factors influencing the adoption, efficiency, and impact of irrigation systems and scheduling methods for irrigation on small and limited resource vegetable and fruit farms in Mississippi; and promoting water quality management techniques for vegetable production. Summary of major project accomplishments will be presented at the conference.<br /><a href="http://wrri.msstate.edu/conference/pdf/diaz_jairo2015.pdf">Download the presentation</a>
Heterogeneous Vertical Flow through Oxbow-Wetlands: Soil Chemistry, Wetland Tree Growth, and Groundwater Recharge
Year: Authors: Lahiri C., Davidson G.R., Threlkeld S.T.
The floodplain of the lower Mississippi River is littered with oxbow lake-wetland systems supporting dense forests of bald cypress and tupelo gum. Fine-grained sediments infilling the oxbows form low hydraulic conductivity plugs that should minimize communication between surface water and underlying groundwater, and produce pervasive reducing conditions in the soils during flooding. In forested oxbows, however, extensive root networks and decaying fallen trees have the potential to produce zones of higher conductivity and preferential vertical flow pathways. Evidence of preferential flow paths has been documented in Sky Lake, an abandoned meander loop of the Mississippi River in northeastern Mississippi. Redox potential measured hourly over an 18 month period revealed isolated zones that became oxidizing when surface water levels exceeded one meter. Changes in groundwater levels in a well located inside the meander loop were also consistent with recharge from the overlying oxbow. Advective delivery of oxygen through portions of the root zone has the potential to enhance tree growth during periods of extended inundation. Several cypress trees have been outfitted to continuously monitor sap flow and radial expansion to identify possible links between growth and changes in soil redox potential that accompany changes in water depth.
Drivers of plant community composition in Delta wetlands
Year: Authors: Shoemaker C., Ervin G.N.
Intensive agricultural practices in watersheds have the potential to lead to high inputs of non-point source pollutants as a byproduct of nitrogen and phosphorus fertilizer applications. Excess amounts of these nutrients can lead to the eutrophication of receiving water bodies and cause water quality degradation at local, regional, and national scales. To combat this problem, wetland restoration is seen as a potential remediation strategy for reducing nutrient loads entering into larger water bodies. However, wetlands differ in their ability to remove nutrients, in part a result of the plant diversity within wetlands. This study examined natural and restored herbaceous wetlands across the northern Delta in Mississippi to determine drivers of plant community composition and their subsequent effect on water quality. Six naturally occurring wetlands along with 24 restored wetlands enrolled in the Wetland Reserve Program (WRP) were sampled across 12 watersheds stratified by expected nitrogen loads (based on USDA agricultural statistics data). Wetlands were visited in May and August of 2014, with species presence and abundance recorded at 50 sampling plots within each wetland. On the restored sites, redvine (<i>Brunnichia ovata</i>) and trumpet creeper (<i>Campsis radicans</i>) frequently were recorded at 50% or more of our sample points per wetland, while knotweed (<i>Polygonum spp.</i>) was common throughout. Additionally, woody species, such as buttonbush (<i>Cephalanthus occidentalis</i>), swamp chestnut oak (<i>Quercus michauxii</i>), slippery elm (<i>Ulmus rubra</i>) and other bottomland hardwood species were found in greater abundance on the six natural sites compared to restored sites. Ongoing analyses are aimed at investigating components of water quality that may be driving or driven by plant species composition in these wetlands.
Water quality-land use interactions in restored wetlands of the Mississippi Delta
Year: Authors: Ervin G.N.
Restoration of former agricultural land to wetlands, through programs such as the Wetlands Reserve Program (WRP) and Conservation Reserve Program (CRP), often focuses on restoring functions such as water quality improvement and wildlife habitat enhancement. However, results are inconclusive as to the long-term successes of these restorations. Our work is aimed at determining whether wetland restorations in the Mississippi Delta achieve sustained water quality improvements, and whether key water quality parameters are influenced by surrounding land use. During the summer of 2014, we assessed vegetation, land use, soils, and water quality in and around 24 restored and 6 naturally occurring wetlands across a gradient of human land use in the Delta. Initial analyses were based on classifying wetlands into watersheds with high, medium, or low levels of agricultural intensity, based on data from the USDA National Agricultural Statistics Service. We found differences in soils and surrounding land use of natural vs. restored wetlands but few differences attributable solely to our a <i>priori</i> classification of wetlands based on surrounding agricultural land use. When we examined correlations between water quality parameters and land use within 200m of the wetlands, we unexpectedly found no significant correlations. Nutrient concentrations were quite high in these wetlands; thus, it is possible that concentrations alone may be uninformative about impacts of surrounding land use. Additional work is planned to examine changes in water quality as surface waters move through these wetlands, as this may be a better metric of ecological function for Mississippi Delta wetlands.<br /><a href="http://wrri.msstate.edu/conference/pdf/ervin_gary2015.pdf">Download the presentation</a>
Groundwater and Surface-Water Interactions of a Stream Reach and Proposed Reservoir within the Pascagoula River Basin: George County, Mississippi
Year: Authors: Killian C., Schmitz D.
This research had two main objectives: quantify surface-water and groundwater interactions along a stream reach, and determine the hydraulic conductivity at the site where two reservoirs are proposed. The stream reach, located in the Pascagoula River Basin in southeast Mississippi, begins at Lake Okatibbee and terminates at Pascagoula, into the Gulf of Mexico. Four USGS continuous gauging stations provided more than forty years of stream discharge data for a hydrograph base-flow-recession analysis, which determined the baseflow component within the stream. The analysis showed that baseflow decreases along the stream reach and increases again before reaching the Gulf of Mexico. Thirteen borehole samples were collected at the sites of the proposed reservoirs in George County, Mississippi to determine the hydraulic conductivity of the sediments, which showed high a hydraulic conductivity. The reservoirs will help to maintain stream ecology as well as increase surface water storage for recreational and industrial purposes.
Overview of Water Quality and Water Resource Research in the Water Quality and Ecology Research Unit, Oxford, MS
Year: Authors: Wade Steinriede R., Locke M.A., Testa S.
The Water Quality and Ecology Research Unit (WQERU) is part of the United States Department of Agriculture - Agricultural Research Service (USDA-ARS) National Sedimentation Laboratory located in Oxford, Mississippi. The stated research mission of the WQERU is to "address issues of water quality/quantity and watershed ecosystem function. Investigations pursue complimentary approaches that consider the entire landscape." This poster outlines some WQERU research that was designed to address issues relating to storm water and irrigation runoff associated with agricultural fields. Current research can be outlined in three main objectives: Objective 1) Evaluate farm and land management practices that have the potential to affect associated environmental issues such as sediment, nutrients, and water quantity. This type of research ranges from plot studies to monitoring and evaluation on the watershed scale. Objective 2) Characterize and quantify the structure, function, and processes of ecosystems associated with agriculture and their response to changes in land management. Objective 3) Perform integrated assessments of the effects of agriculture on ecosystem services for watershed-scale endpoints. This includes long-term watershed-scale monitoring programs along with modeling and using data collected from sampling and monitoring to improve the models. Through the use of a holistic grouping of studies, the WQERU is addressing needs for knowledge in the agricultural landscape.
Groundwater and surface-water dynamics in the Mississippi Delta: a coupled monitoring-modeling approach for better understanding and management of gro
Year: Authors: Barlow J.R., Connor J.H.
<p>The Mississippi River alluvial plain in northwestern Mississippi (referred to as the Delta), once a floodplain to the Mississippi River covered with hardwoods and marshland, is now a highly productive agricultural region of large economic importance to Mississippi. Water for irrigation is supplied primarily by the Mississippi River Valley alluvial aquifer, and although the alluvial aquifer has a large reserve, there is evidence that the current rate of water use from the alluvial aquifer is not sustainable. Prior to extensive use of groundwater for irrigation, the regional groundwater flow path generally followed the topography of the alluvial plain, discharging to the streams and rivers within the Delta. Presently, the regional groundwater flow path is intercepted by a large cone of depression in the central Delta with maximum drawdown occurring in Sunflower County, formed as a result of groundwater pumping for irrigation. Water-level declines have resulted in decreased groundwater discharge to streams to the extent that many stream reaches in the Delta are presently net losing streams throughout the year. These changes in flow to and from the aquifer have decreased the amount of water available within the alluvial aquifer and have diminished many ecosystem services provided by groundwater discharge to streams such as maintaining baseflow in streams, regulating stream temperature regimes for aquatic biota, and buffering the transport of contaminants through the streambed interface.</p> <p>An effort is currently underway to update and enhance an existing regional groundwater flow model in order to develop and run conjunctive water management optimization scenarios. This effort is jointly conducted by personnel from the U.S. Geological Survey and the Mississippi Department of Environmental Quality through a memorandum of understanding between the two agencies. Key revisions to the model include updating the model through 2014 with the addition of more recent water use data, precipitation and recharge data, and streamflow and water-level observations.</p>
Water quality in Bangs Lake: Effects of recurrent phosphate spills to a coastal estuary
Year: Authors: Dillon K., Caffey J., Carmichael R.H., Cressman K., Woodrey M.
Bangs Lake, an estuarine water body in the Grand Bay NERR, has been the site of three industrial phosphate spills from a nearby fertilizer plant since 2005. Due to restricted tidal exchange in Bangs Lake, these events have had long lasting effects on water column phosphate concentrations which may stimulate biological activity and alter the biogeochemical cycling of essential elements within the water column and the sediments. To determine the fate of excess phosphate from the industrial spills, researchers measured soluble reactive phosphate concentrations in sediment pore water and total particulate phosphate concentrations from sediment cores (0-25 cm depth) from four locations: North Bangs Lake (closest to spill locations), Bangs Lake, and two low impact reference sites (Bayou Cumbest and Bayou Heron). Researchers also conducted phosphate adsorption experiments and measured benthic chlorophyll concentrations with sediments from these sites to determine if the excess PO4 was fertilizing benthic microalgae to determine the fate of this excess PO4. Pore water phosphate concentrations were highest (21 uM) from 10 to 20 cm depths in North Bangs Lake cores however pore water from the surface sections of these cores had much lower phosphate concentrations (<0.5 uM). Pore water from the Bangs Lake cores consistently had elevated phosphate concentrations (2 to 5 uM) throughout the core length while pore water phosphate concentrations from one reference site were much lower (<0.7 uM), likely reflecting background levels. Phosphate adsorption experiments show that surface sediments from North Bangs Lake and Bayou Cumbest rapidly stripped phosphate from solution to final concentrations of <3 uM while surface sediments from Bangs Lake had greatly reduced phosphate adsorption capacity with much higher final concentrations (24 to 32 uM) indicating these sediments are nearing saturation. Sediment chlorophyll a concentrations were higher in Bangs Lake compared to the reference site. Sediment chlorophyll a was significantly correlated with extractable phosphate concentration in sediments (r = 0.88). In addition, grow out experiments with amendments of phosphorus to water and sediment samples stimulated the growth of cyanobacteria capable of fixing nitrogen.
Refinement and regionalization of phosphorus assessment tools in Mississippi
Year: Authors: Ramirez-Avila J.J., Oldham J.L., Ortega-Achury S.L., Osmond D., Martin J.L., Locke M., Read J.J.
Phosphorus is a major nonpoint source pollutant that causes eutrophication in surface waters. Phosphorus (P) Indices are applied assessment tools used to identify agricultural fields most vulnerable to P loss by accounting for major source and transport factors controlling P movement. There is a wide range in formulation and management recommendations of P Indices among the southern states leading to differences in P-management recommendations under relatively similar site conditions. This situation creates the need for rigorous evaluations of P Indices to determine directional and magnitudinal correctness. Mississippi State University-based investigators participate in a southern multistate research program with the objectives to coordinate and advance P management in the region by ensuring that P assessment tools developing using guidance in the 2011 NRCS 590 standard are compared to water quality data. The research goals include producing tools that provide more consistent results across physiographic regions that will encourage greater similarity between southern state P Index ratings and ensuing recommendations. Values of annual P loss measured in two Mississippi physiographic regions, i.e. agricultural fields in the Mississippi Delta and pastures in the poultry production counties in South Mississippi, are used to compare southern P Index assessments against water quality data, and to calibrate and validate the Agricultural Policy/Environmental eXtender (APEX) model. Results will show the assessment for P loss vulnerability estimated by different southern P Indices and the performance of the APEX model before and after calibration and validation procedures for the proposed scenarios.
Numerical Modeling of Flow and Mercury Distribution in Enid Lake, Mississippi
Year: Authors: Chao X., Hossain A.K., Cizdziel J., Jia Y.
The Yazoo River Basin is the largest basin in Mississippi. Four large flood control reservoirs: Arkabutla Lake, Sardis Lake, Enid Lake and Grenada Lake, are located in this region, providing significant natural and recreational resources. The soils in this region are highly erodible, resulting in a large amount of sediment discharged into the water bodies. Sediments are normally associated with many pollutants and greatly affect water quality and aquatic lives. Mercury concentrations in water, sediment and fish in Enid Lake are relatively high, and a fish consumption advisory was issued by Mississippi Department of Environmental Quality (MDEQ) in 1995. In this study, a numerical model was developed based on CCHE3D, a three-dimensional free surface hydrodynamic, sediment and water quality model to simulate the flow, sediment and mercury distributions in Enid Lake. Total mercury in water and sediment were simulated, and the major processes, including advection, diffusion, adsorption/desorption, bed release, atmosphere deposition, settling, etc., were considered in the model. This model was calibrated and validated using field measurements and remote sensing data. This model provides useful tools for understanding the fate and transport of mercury in natural lakes.
Developing Numeric Nutrient Criteria For Mississippi
Year: Authors: Young A., Caviness K.
Nutrient loads, including nitrogen and phosphorus, have been a major cause of impairments in water bodies nationwide. In 2001 the USEPA developed an Action Plan requiring that all states develop numeric nutrient criteria in order to protect uses from nutrient pollution. Since then, the Mississippi Department of Environmental Quality (MDEQ) has been active in pursing this goal, including creating a Nutrient Criteria Development Plan and collecting data to derive scientifically defensible nutrient criteria. A technical advisory group (TAG) consisting of members of state, federal, and research scientists has been formed to aid MDEQ in deriving these criteria with their technical knowledge and regional experience. The methods used to determine criteria are data compilation, classification of waters, and data analysis. In an effort to be more scientifically defensible, MDEQ is applying the multiple lives of evidence approach for nutrient criteria development. The multiple lines of evidence approach involves looking at several lines of analysis, such as distributional analysis, stressor-response, scientific literature, and water quality models to create a final endpoint. In addition to developing criteria, MDEQ recognizes that moving forward the implementation of these criteria is also a priority of the state. An implementation work group has been formed to address issues such as permits, assessment, total maximum daily loads (TMDLs), waste load allocations (WLAs), and watershed planning. The MDEQ, along with the support of the TAG and the involvement of stakeholders, are making great strides in developing criteria for the Mississippi's rivers, streams, lakes, coastal and Delta waters.
Leaching of copper from different copper treated woodwastes
Year: Authors: Singleton B., Borazjani H., Cox M.
There has been a significant increase in production of copper treated lumber since voluntary halt in production of chromated copper arsenate (CCA) for residential use by the wood treating industry. Disposal of copper treated wood wastes have become an environmental issue for companies using these products for residential applications. This study evaluated recovery of copper from sawdust of copper azole(CA),micronized copper azole(MCA), azole copper quat(ACQ), and micronized copper quat(MCQ) using two different extraction procedures(toxicity characteristic leaching procedure(TCLP), and sonication) in acidic water. No significant differences in copper recovery were observed between CA and MCA by both extraction procedures. The same results were observed for ACQ and MCQ also. However, copper recovery for MCQ and ACQ were significantly higher than CA, and MCA.
Diamondhead MS BMP Demonstration Site, Outreach Tools and Model Ordinance
Year: Authors: Gallo W.C.
Researchers at Mississippi State University along with the Mississippi Department of Environmental Quality (MDEQ) have developed new BMP demonstrations, educational outreach material and policy tools for coastal Mississippi. A proposal for a BMP demonstration site was developed that promotes resilient community design and development in Diamondhead, MS. The demonstration site is designed to accommodate future commercial development, protect watershed health, and demonstrate small and large scale structural BMPs from infiltration basins to regional detention. Two presentations and two brochures were also developed that focus on homeowners and policy makers. Both sets of documents are designed to provide a broad overview of the tools, policies and practices homeowners and policy makers can adapt to better protect their a home watershed and a community watershed. All documents will be available for use from the MDEQ to meet NPDES Phase II education and outreach requirements. Lastly, a new model ordinance was created based on a review of other model ordinances throughout the country and adapted for the specific needs of coastal Mississippi. The ordinance is designed to be flexible and adaptable to any community's requirements by providing options and insights into the choices available throughout the document. This document will also be available for municipalities use from the MDEQ.
The Migratory Bird Habitat Initiative: Managing Waterbird Habitats After The 2010 Gulf Oil Spill
Year: Authors: Kaminski R.M., Davis J.B., Webb L., Tapp J., Weegman M.M.
In response to the 2010 Deepwater Horizon Gulf Oil Spill, the USDA Natural Resources Conservation Service (NRCS) funded the Migratory Bird Habitat Initiative (MBHI), providing landowners in eight Gulf coastal states $40 M in cost-share assistance to manage wetland habitats for waterbirds inland from the spill through 1-3-year contracts. As part of the comprehensive MBHI, we quantified (1) waterbird use of MBHI managed (i.e., primarily artificial flooding), non-managed, and other wetlands and (2) potential food resources for these birds in wetlands in the Lower Mississippi Alluvial Valley (MAV). Managed Wetlands Reserve Program (WRP) lands received significantly greater use by waterbirds than passively or non-managed WRP easements. In Louisiana and Mississippi, nearly 3 times more dabbling ducks (Anatini) and all ducks combined (Anatinae) were observed on MBHI than on non-managed WRP wetlands. Additionally, waterbirds other than waterfowl and shorebirds were nearly twice more abundant on MBHI than non-managed WRP wetlands. In Arkansas and Missouri, MBHI wetlands attracted over 2 times more dabbling ducks than non-managed WRP wetlands. Concerning food abundance and habitat carrying capacity for waterbirds, MBHI wetlands in Louisiana and Mississippi contained =1.26 and =1.53 times more total seed biomass and biomass of seeds known to be eaten by waterfowl, respectively, than non-managed WRP wetlands. In Arkansas and Missouri, seed biomass during winter was 21% greater on MBHI wetlands than non-managed WRP wetlands. While no significant differences in aquatic invertebrate biomass or number of invertebrate families were detected between managed and non-managed WRP wetlands in Arkansas and Missouri, production of invertebrates during autumn was 3 times greater on MBHI wetlands than non-managed WRP wetlands. During winter, invertebrate biomass was approximately 40% greater on MBHI and non-managed WRP wetlands than public-owned managed wetlands in these states. Our evaluation implies that MBHI management increased waterbird use and potential foraging carrying capacity of WRP wetlands for waterbirds and possibly provided alternative habitats for these birds inland from oil impacted Gulf coastal wetlands. Continued financial incentives to landowners in the MAV and nationally to manage wetlands at conservation easements following restoration have the potential to increase contribution of private lands to waterbird habitat availability and carrying capacity.
Mississippi Water Resources Inventory & Projections for Economic Development
Year: Authors: Linhoss A., Balwebber J., Pote J.
Mississippi's water resources are an important part of the state's economy, environment, and quality of life. Water is an essential commodity and the importance of water to Mississippi's economy is clear given the number of economic sectors that rely on the resource (e.g. agriculture, industry, energy, and public supply). However, the economic value of water is in many ways immeasurable because (1) it provides life whose economic value is incalculable, (2) there many external factors that are often not accounted for in the market value of water (e.g. pollution and environmental impacts), (3) users often self-supply and do not pay a market value for the resource, and (4) water is a complex resource whose value depends on volume, timing, reliability, and quality. The objective of this research is to assess the value of Mississippi's water resources within an integrative environmental and economic development framework. Mississippi is blessed with rich water resources. The state has the second highest rate of annual rainfall in the continental U.S. and major ground water aquifers underlie 83% of the state. River flow through Mississippi is dominated by the Mississippi River which discharges an average of 723,000 cubic feet per second. When combined, the rest of the rivers in Mississippi discharge approximately 60,000 cubic feet per second, which is only 7% of the flow in the Mississippi River. Eight dams in the state (0.2%) have the primary purpose of water supply and Mississippi has the least number of reservoirs with the purpose of water supply, relative to neighboring states. Mississippi's water use is dominated by groundwater and agriculture. 32% of Mississippi's water withdrawal permits are from surface water and the remaining 68% are from ground water. Irrigation for agriculture is the primary groundwater beneficial use category and industry is the primary surface water beneficial use category. Mississippi's high dependence on groundwater runs opposite the trend for most of the comparison states and Mississippi withdraws the least amount of groundwater relative to neighboring states. As Mississippi moves forward through economic and community development it is important to recognize the environmental and economic values of water. This research provides a broad perspective for assessing water use in Mississippi as well as understanding the vulnerable aspects of our water resources.
The Mississippi Freshwater Assessment: A New Tool for Supporting Decision Making for Mississippi's Freshwater Resources
Year: Authors: Piazza B.
TNC is in the early phases a project to compile, analyze, and present scientific information to improve conservation and protection of Mississippi's freshwater resources. This comprehensive statewide freshwater assessment is a scientifically sound evaluation of watershed and landscape integrity (i.e., land use and cover, floodplain connectivity, channelization), water quality, surface flow, groundwater trends, and biological health (i.e., trends in species diversity indicators,) of all of the state's watersheds. The data resource and analysis tool will provide a powerful, online mapper with decision-support capability to facilitate the development of freshwater science and conservation objectives and prioritize freshwater conservation statewide. It will be freely available and useful for any stakeholder, including policy- and decision-makers, environmental resource managers, local watershed conservation groups, and the general public, and will allow both technical and lay audiences to evaluate the effects of current and future water use and watershed development proposals. This assessment will provide the capability to draw attention to the status of Mississippi's watersheds, develop agency, NGO, and industry partnerships, and provide quickly accessible facts and figures to support science-based and sound policy outcomes about water. This presentation will describe the framework, components, and capabilities of the assessment system, and will investigate an example of a similar system built for Louisiana. When complete, our Mississippi Freshwater Assessment will integrate with Louisiana's system as well as TNC's Gulf of Mexico Resilience decision support tool (maps.coastalresilience.org) to move toward the ultimate goal of providing a common approach and framework for supporting decision making and management of freshwater and coastal resources across the northern Gulf of Mexico.
Austin's Quadrant: a new framework for assessing water use models
Year: Authors: Czarnecki J.M., Kröger R., Omer A.R.
Although water resources are frequently discussed as an issue of Tragedy of the Commons, this paradigm has well-published shortcomings which make it irrelevant in some situations. A new framework for water use models is proposed where regions are evaluated on two continua, infrastructure and supply. A quadrant is formed wherein regions in quadrant I experience both ample water supply and adequate infrastructure with which to utilize available supply. Regions falling within quadrants II and IV experience a shortage of either supply (II) or infrastructure (IV) but adequate levels of the opposite factor. Regions falling within quadrant III bear the double burden of limited supply and infrastructure. This paper explores case studies within the four quadrants and attempts to answer the questions: (1) What does it take to move from quadrants III or IV to quadrants II or I, and more importantly (2) how do regions in quadrant I not move into quadrant II? Engineered infrastructure must increase concomitantly with governance infrastructure or regions will slide farther down the supply continuum. Education and outreach hold the most promise to shoring up the future of water resources for these regions. Users who make the connection between individual use and its effect on aquifer supply are more likely to engage in conserving behavior and to be more accepting of regulation of use. If adequate education alone is unable to stem overuse, then at least regulation will be supported.
An Assessment of Private Wells Used for Drinking Water in Mississippi and Alabama
Year: Authors: Barrett J., Grammer P.
Most residents of Mississippi and Alabama are served by one of the over 1,700 public water systems in these states. Having access to a public water system provides citizens with safety and quality of water through the regulatory enforcement of the Mississippi State Department of Health-Bureau of Public Water Supply (MSDH) and the Alabama Department of Environmental Management (ADEM). Mississippi and Alabama citizens on private wells do not have the luxury of knowing the quality and/or quantity of their water on a regular basis. Unfortunately, a reliable method for determining the population that depends on a private well for their water supply has not existed since the 1990 census. This presentation will compare currently available methods and present a new methodology for estimating private well usage in Mississippi and Alabama. This novel method uses connections reported to the Safe Drinking Water Information System adjusted to account for non-residential connections, along with census data to generate improved estimates that are quite different from other available sources. This method has been used to generate well usage estimates for all counties in Mississippi and Alabama that can be utilized to better strategize water infrastructure improvements and well monitoring programs.
Enhancing the USGS Streamgaging Network in the Mississippi River Basin: Continuous Water-Quality and Groundwater Data
Year: Authors: Roberts B.A.
The U.S. Geological Survey (USGS), Mississippi Water Science Center, in cooperation with the U.S. Army Corp of Engineers, Vicksburg District, is in the process of enhancing selected streamgages throughout the Mississippi River Basin to include continuous hourly water-quality and groundwater data. In Mississippi, the USGS is installing a ultraviolet nitrate sensor to collect continuous nitrate data, and a water-quality sonde to collect continuous temperature, specific conductance, turbidity, chlorophyll-a, and dissolved organic matter data on the Mississippi River near Vicksburg, Miss., and the Bogue Phalia near Leland, Miss. Both sites will be operated in conjunction with the USGS National Water Quality Assessment Program to understand nitrate dynamics during extreme hydrologic conditions such as baseflow and storms and to provide a more complete data set for future nitrate load calculations.
Quality of water in public supply wells located in the Southeastern Coastal Plain and Coastal Lowlands aquifer systems, Mississippi, 2013
Year: Authors: Welch H.L., Barlow J.R.
Groundwater provides over one-third of the water used for public supply in the United States and nearly half of the water used for public water supply in the southeastern United States. In 2013, the U.S. Geological Survey's National Water Quality Assessment Program began studies to provide nationally consistent water-quality data from principal aquifer systems that account for the majority of withdrawals for public supply throughout the United States. Two of these principal aquifers, the Southeastern Coastal Plain and Coastal Lowlands aquifer systems, were selected for sampling in 2013. These aquifer systems are located in the southeastern part of the United States, and each consists of unconsolidated to semiconsolidated sand, silt and clay deposits that thicken and dip coastward. The Southeastern Coastal Plain aquifer system spans approximately 90,000 sq miles and includes parts of 6 states, and the Coastal Lowlands aquifer system spans approximately 98,000 sq miles and includes parts of 5 states. Public-supply wells were selected for sampling using an equal-area grid approach to ensure a spatially unbiased sampling distribution.
Indirect Regulation of the MRVA Aquifer: Options for the Mississippi Delta
Year: Authors: Massey J.H.
An intensively used resource requires intensive management. The Mississippi River Valley Alluvial aquifer is an intensively used resource whose value will only grow as demand for irrigation continues to rise. Effective regulation is necessary in the management of commonly-held resources, and may be direct or indirect in form. Direct regulation includes actions such as permitting, metering, monitoring of water extractions, and assessment of extraction fees. Indirect regulation seeks to manage a resource without coming in direct contact with it. Educational and certification programs represent indirect forms of regulation. Water-resource management literature suggests that indirect regulation is more effective and practical in situations where large numbers of geographically-diffuse extractors use the resource. This is because the cost of effective direct regulation is often prohibitively expensive. Given that there are more than 18,000 active agricultural groundwater well permits distributed over a 17 county area in the Mississippi Delta, indirect regulation will, by necessity, play an important role in the successful management of the alluvial aquifer. The purpose of this presentation is to discuss options for the indirect regulation of the Mississippi River Valley Alluvial aquifer.
Nutrient Reduction In Mississippi: Partnering For Success
Year: Authors: Bhowal P.
Mississippi is blessed with abundant water resources, and protection of these water resources is essential to ensure sustainability of Mississippi's ecosystems and economies. One of the biggest challenges for Mississippi's surface waters, the Mississippi River and the Gulf of Mexico is the presence of excess nutrients in these waters. The Gulf of Mexico contains a hypoxic zone that is a result of nutrient-rich water from the Mississippi River flowing into the Gulf. Nutrients, in the form of nitrogen and phosphorus, come from a variety of sources including farmlands and lawns where fertilizers are used, wastewater treatment facilities, animal wastes from farms and pasturelands. Accordingly, the issues of nutrient pollution and Gulf Hypoxia have become priorities for Mississippi's Delta, Upland and Coastal regions that contribute significant nutrients loading to the Gulf. Mississippi's approach to reduce nutrient loadings within basins and to the Gulf of Mexico is a highly collaborative, stakeholder supported process centered on development and implementation of comprehensive nutrient reduction strategies for the Delta (December 2009), Coastal (March 2011), and Upland (March 2011) regions of the state. These strategies identified 11 strategic elements to help reduce nutrient loading to Mississippi's surface waters. Over 50 staff from multiple state and federal resource agencies and other organizations in Mississippi have been working together to help develop and implement these comprehensive nutrient reduction strategies. Implementation includes engaging stakeholders, characterizing watersheds, determining status and trends, documenting management programs, establishing quantitative targets, selecting analytical tools, identifying/implementing established and innovative best management practices (BMPs), designing monitoring work, providing incentive and funding, and communicating results. These nutrient reduction strategies are currently being implemented in 10 priority watersheds in the Delta (7), Upland (2), and Coastal (1) regions of the state.
Benefits of On-Farm Water Storage Systems in Porter Bayou Watershed
Year: Authors: Tagert M.L., Paz J.O., Pote J.W., Kirmeyer R.L.
Since the 1970's, groundwater levels in the Mississippi Alluvial Aquifer have decreased as the number of irrigated acres in the Mississippi Delta has increased. Today, there are roughly 18,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer, with approximately 50,000 new irrigated acres added both in 2011 and 2012. As concern has grown over groundwater declines and increasing fuel costs to run irrigation pumps, farmers have been implementing more irrigation conservation measures, such as on farm water storage (OFWS) systems. These systems began appearing in the Mississippi Delta in 2010 in conjunction with the implementation of the Mississippi River Basin Healthy Watersheds Initiative (MRBI). OFWS systems typically are surrounded by fields that are padded and piped, directing rainfall and runoff to a tailwater recovery ditch, from where it is then pumped into a pond for storage. Water is pumped from the pond and used for irrigation at a later date. These systems offer farmers the dual benefit of providing water for irrigation and also capturing nutrient rich tailwater for on farm reuse. This presentation will give an update on the project, which has monitored water savings and nutrient levels at two OFWS systems, one each at Metcalf Farm and at Pitts Farm, in the Porter Bayou Watershed, Mississippi. Data collection began in February 2012 and is ongoing, with water samples collected for analysis every three weeks throughout the growing season from March-October and every six weeks through the off season. Cumulative readings were also taken on flow meters to measure water use from the storage pond. The ability of these systems to reduce downstream nutrient concentrations has been mixed, with systems performing better when the tailwater recovery ditch is not full and can contain runoff on site. Thus, better management will improve the nutrient reduction potential of these systems. The water savings potential of these systems has been substantial. Metcalf Farm used 42 and 17 million gallons of water from the storage pond in 2012 and 2013, respectively; Pitts Farm used 60 and 56 million gallons of water from the storage pond in 2012 and 2013, respectively. These amounts reflect savings in groundwater that was not pumped from the Mississippi Alluvial Aquifer.
Assessing new BMPS: efficiencies of a Tailwater Recover System and On-farm Storage Reservoir
Year: Authors: Omer A., Kröger R.
The Lower Mississippi Alluvial Valley in Mississippi is economically important due to its highly productive agricultural land. However, producers in this region face two predominant environmental issues that are inherently linked to the agricultural industry. Firstly, intensive agriculture practices which have resulted in increased surface transport of nutrient laden sediments, contributing to eutrophication in receiving waters and to the Gulf of Mexico Hypoxic Zone. Secondly, current water withdrawals from the Mississippi River Valley alluvial aquifer for irrigation during the growing season when precipitation is minimal are not sustainable. These issues threatening environmental resources necessitate best management practices (BMPs) and groundwater conservation. This research investigates BMP systems as water resource conservation methods. Such practices include surface water capture and irrigation re-use systems, referred to as tailwater recovery systems (TWR) and on-farm storage reservoirs (OFS). A single year investigation of two TWRs and one OFS highlighted water holding capacities for irrigation reuse and functionality for nutrient capture as well. Research also included the investigation of the delivery of nutrients and water from a TWR to rice fields during the 2013 growing season, which allowed for the calculation of potential economic savings by a producer pumping surface water rather than ground water. While this research is ongoing, initial investigations indicate that TWRs and OFSs have much promise for water conservation in the Lower Mississippi Alluvial Valley.
Using low-grade weirs as a BMP: Effects on nutrient remediation and microbial denitrification
Year: Authors: Poganski B., Kröger R.
Although the term "anthropogenic influence" often has a negative connotation surrounding it, it encompasses all human influences to the environment, including flood control, restoration, and conservation practices. Interestingly, in addition to land use purposes, water management practices, such as BMPs, can also influence factors affecting denitrification. A study was conducted evaluating the composition of microbial communities involved in key processes of denitrification following physiochemical changes introduced by low-grade weir implementation. Investigations of functional genes involved in denitrification via quantitative polymerase-chain reaction (qPCR) included those encoding for subunits of nitrate reductase (nirK, nirS) and nitrous oxide (nosZ). Understanding how low-grade weirs alter drainage environments in such a way that impacts microbial community structure and function, and subsequent nutrient transformations, which will advance engineering and remediation strategies. Understanding the impacts of low-grade weirs on nutrient reduction capacities will also provide a greater understanding of how to improve nutrient management strategies to reduce Gulf of Mexico hypoxia.
Effects of organic carbon amendments on nitrogen removal in agricultural drainage ditch sediments
Year: Authors: Faust D.R., Kröger R.
Agricultural fertilizer applications have resulted in loading of nitrogen nutrients to agricultural drainage ditches in the Lower Mississippi Alluvial Valley, contributing to the Gulf of Mexico hypoxic zone. Previous studies have observed that nitrogen loading decreases with implementation of best management practices within and in proximity to aquatic ecosystems in agricultural settings. The purpose of this study was to determine effects of organic carbon amendments on nitrogen removal in agricultural drainage ditch water at various lengths of time and carbon-to-nitrogen (C:N) ratios. In one experiment, control, dissolved organic carbon (DOC), and particulate organic carbon (POC) amendment groups were prepared in laboratory microcosms for time treatments of 3, 7, 14, and 28 days with six replicates per treatment. In a second experiment, control, DOC, and POC amendment groups were prepared in microcosms at C:N ratios of 5, 10, 15, and 20 with six replicates per treatment. A permutational multivariate analysis of variance was used to detect statistically significant differences in nitrogen nutrient among treatments (F11,60=19.0, P=0.001 and F8,45=23.2, P<0.001). Mean increases of 3.27 ± 0.52 and 19.2 ± 4.5 mg N L-1 of total nitrogen were observed in overlying water of all treatments of experiments one and two, respectively. However, 60-100% removal of nitrate-nitrogen in overlying water was observed in all treatments with removal occurring in DOC and POC treatments. These results indicate that amendments of organic carbon made to drainage ditch sediments increase nitrate-nitrogen removal, particularly over longer periods of time. Any amendments of DOC increase N removal, regardless of C:N ratio, while amendments of POC at a C:N ratio of five are optimal for N removal. This study provides support for using organic carbon amendments as a best management practice in agricultural drainage ditches.
Distribution and Cycling of Mercury Species in Wetlands and Reservoirs in Northern Mississippi
Year: Authors: Cizdziel J., Brown G.
Methylmercury (MeHg) is a neurotoxin that accumulates in tissues and biomagnifies up the aquatic food chain. Fish consumption advisories have been issued Enid Lake and the Yocona River, a large reservoir and its tributary in north-central Mississippi. This study examined the origin, distribution, and cycling of mercury species in the Yocona River, Enid Lake and associated wetlands. Environmental conditions can have a dramatic impact on the production, transport and fate of Hg species in a given area. Wetlands play a critical role in the cycling of Hg in watersheds and have been shown to be net sources of MeHg to ecosystems. Total-Hg and MeHg were determined seasonally over the course of two years in the inflow and outflow of Enid and Sardis Lakes, in associated wetlands. The Hg species were also measured during storm events (i.e., in runoff from urban, agricultural, and wetland/forest areas). A range of water quality parameters were measured to determine the primary factors controlling the distribution and transport of Hg species in the watershed. The project served as an important step toward building a mass balance for mercury in Enid Lake. Key findings include: - Wetland areas were determined to be hotspots for MeHg in the watershed with relatively high concentrations in water and fish - Levels of Hg in river water were highest at peak flows during storm events. - Forest soil and wetland sediment had higher levels of Hg and organic matter than agriculture soils. - Hg levels were highest in the urban runoff, followed by forest/wetland, and agriculture. - Runoff from highly erodible agricultural areas likely provides the largest input of Hg to Enid Lake by transport of particle-bound-Hg. - MeHg in wetland water was about double that found in lake water, and both spiked during the summer months, with wetlands reaching as high as 1.3 ng/L. - MeHg in the wetland water was negatively correlated with oxidizing reducing potential. - The net flux of T-Hg in Enid Lake was the most negative in the winter due to lowering of lake water levels to accommodate spring rains, and most positive during storm events, suggesting that rain storm events contribute a significant portion of Hg to the lakes. - The net flux of MeHg in Enid Lake was more negative in the summer than fall and spring due to higher methylation and evaporation rates.
Flood Inundation Mapping to Aid Emergency Management Planning in the Cities of Hattiesburg and Petal
Year: Authors: Storm J.
Many cities throughout Mississippi are located on or near major rivers or streams. As a result, residential, commercial, and industrial areas, as well as transportation structures can be at risk when flooding occurs. The cities of Hattiesburg and Petal are located along the Leaf River and have experienced flooding in the past including major events in 1961, 1974, and 1983. The largest recorded flood event occurred on April 15, 1974 and affected approximately 6,000 people and caused damages in excess of $8.3 million (1974 value unadjusted for inflation). The U.S. Geological Survey (USGS), in cooperation with the Cities of Hattiesburg and Petal, Forrest County, Mississippi Emergency Management Agency, Mississippi Department of Homeland Security, and the Emergency Management District, has developed a series of flood inundation maps at 1-foot increments ranging in stage from bank-full (22.0 ft) to approximately the peak of record flood (34.0 ft) for a 6.8 mile reach of the Leaf River through the cities. A one-dimensional steady-flow model was calibrated with the stage/discharge relationship at the USGS stream gaging station 02473000 Leaf River at Hattiesburg, MS (http://waterdata.usgs.gov/ms/nwis/uv/?site_no=02473000&PARAmeter_cd=00065,00060), and flood profile information obtained following the 1974 event. The model results were coupled with land surface elevation data from Light Detection and Ranging (LiDAR) surveys and GIS to produce inundation maps depicting the areal extent of flooding in Hattiesburg and Petal at pre-defined river stages. The inundation maps are available to the public through a web based interactive mapper that allows the user to select the river stage and then display the corresponding inundation map. Estimated water depths are shown by clicking anywhere within the inundated area on the map. Emergency management personnel will be able to use the inundation maps to manage and plan a course of action for future floods by pre-determining affected residences, businesses, municipalities, and roadways at forecasted National Weather Service (NWS) flood levels. Citizens will be able to visually determine what affect there may be to their property or business and take appropriate action ahead of time. The maps are available to the public through the USGS and from the NWS at the following links: http://wim.usgs.gov/FIMI/ http://water.weather.gov/ahps/inundation.php
Quantitative Estimation of Suspended Sediments and Associated Mercury Concentration in Enid Lake Using Remote Sensing Techniques
Year: Authors: Hossain A., Chao X., Cizdziel J., Jia Y.
The streams, lakes, and reservoirs in the Yazoo River Basin provide significant natural and recreational resources in Mississippi. However, since the soils in this region are highly erodible, large amount of sediments are discharged into the water bodies. Sediments are often associated with pollutants, which cause many water bodies in this region to be impaired due to the contaminated sediments. Mercury is one of the widely distributed and persistent pollutants in this environment. Mississippi currently has 11 water bodies under fish consumption advisories for mercury, including Enid Lake. To study the mercury contamination issue in the Enid Lake, the National Center for Computational Hydroscience and Engineering at the University of Mississippi has an on-going research project funded by the Mississippi Water Resources Research Institute and USGS to study the transport, fate, and risk of mercury in Enid Lake. As one of the tasks of this project the potential of the remote sensing techniques were explored to estimate the mercury concentration associated with suspended sediments in Enid Lake. Suspended sediment concentration has been estimated and mapped successfully using remote sensing for the last three decades. Different approaches and algorithms had been developed over time for SSC estimation using optical satellite data. Several studies had success in estimating total suspended sediments (TSS) using simple linear regression techniques involving the Moderate-resolution Imaging Spectroradiometer (MODIS) visible and near infra red (VNIR) data and in situ measurements. Similar approach was used in this study to estimate TSS and associated mercury concentration in Enid Lake, MS. The correlation coefficients of the regression equations were obtained using in situ measurements of TSS and mercury from two field campaigns, and near-real time reflectance values of the VNIR bands of MODIS imagery. Preliminary results indicate that these regression equations can be used for quantitative estimation of TSS and associated mercury in Enid Lake with reasonable accuracy
An Integrated Watershed Approach to Water Sanitation and Hygiene priorities for Lake Chivero, Zimbabwe
Year: Authors: Buka H., Linhoss A., Pote J.
This paper describes an integrated watershed approach to water sanitation and hygiene for a water supply reservoir near Harare, Zimbabwe`s capital city. From the construction of the lake to the present, considerable difficulties have been experienced in water quality and water treatment. Discharges from urban and rural agriculture, sewage treatment works and industries have caused severe stresses on the lake's water quality. To combat eutrophication in the mid-1970s, a Hydrobiology Research Unit was established to facilitate pollution research and a biological nutrient removal sewage treatment plant was also installed. This was successful for a decade but afterwards water quality started to deteriorate due to increases in population. The original sewage treatment plants were designed to handle 18 million liters of human waste a day for a population of about 500,000 people but now the estimated population has exceeded 1.4 million people therefore overloading the sewage works. Continued deposition of sewage effluents has contributed to the spread of aquatic weeds such as water hyacinth (Eichhornia crassipes), blue-green algae (Anabaenopsis sp) and spaghetti weed (Hydrocotyle ranunculoides). The weeds strive under a constant supply of nitrogen and phosphorus as they are the major nutrients in the Lake. The area around the lake has been designated as a wildlife sanctuary, which offers the potential for managing water quality better. In 1997 there were recorded fish kills especially the Green headed Tilapia due to low levels of oxygen. A total of 11,735 cholera cases were recorded as of December 2008 due to poor sanitation and water shortages. For these reasons the objective of this review is to assess the integrated impacts of water quality on the environment and sanitation throughout the lake, watershed, and water supply service area.
Regional Rainfall Frequency Analysis and drought reduction in the Tombigbee River Basin
Year: Authors: Ramirez-Avila J.J., McAnally W.H., Tagert M.L., Ortega-Achury S.L.
A regional frequency analysis was conducted for precipitation to bring more detailed information about the amount and distribution of rainfall over the Tombigbee River Basin to promote efficient water resources management in the study area. In addition, the results of the regional frequency analysis were combined with climatological drought reduction information to determine the probability that a cumulative precipitation depth needed to end a drought will be equaled or exceeded at least once in a specific season in the Tombigbee River Basin. A total of 28 precipitation gages in eastern and northeastern Mississippi and western Alabama were included in the study representing 1,352 station years of record. A regional analysis methodology was utilized, and the Tombigbee River Basin was considered a homogeneous region to increase the dataset and improve the reliability of precipitation-frequency estimates. The International Center for Integrated Water Resources (ICIWaRM) Regional Analysis of Frequency Tool (ICI-RAFT) was used to develop the regional frequency analysis. The software involves the application of the L-moments to characterize the variability, skewness and kurtosis of the data, determine heterogeneity in the region, and assist in the identification of appropriate regional probability distribution(s). Verification of results indicated that the selected frequency distributions provide reliable exceedance values for precipitation. Results also showed that spring would be the season with a more probable chance of recovery from a moderate or severe drought in the Tombigbee River Basin.
Interdisciplinary Assessment of Mercury Transport, Fate and Risk in Enid Lake, Mississippi
Year: Authors: Chao X., Cizdziel J.V., Willett K., Hossain A.K.
Enid Lake is one of the important large recreation lakes in Mississippi, and the mercury level is relatively high compared with other large lakes. This research brought together a team of scientists that with their expertise in analytical chemistry, remote sensing technology, hydraulic modeling and risk assessment to study the transport, fate and risks of mercury in Enid Lake. Two field measurements were conducted in spring and fall to measure the flow, sediment and mercury in Enid Lake. The remote sensing technology was applied to analyze the concentration distributions of sediment and mercury in the whole lake, and the results are generally in good agreement with measured data. A numerical model was developed to simulate the flow, sediment, and mercury in the lake, and the interaction between the mercury and sediment was taken into accounted. Risk assessment was conducted to analyze the potential risk of mercury both in the environment and human fish consumption. The research results help us understand the transport mechanisms of sediment and mercury in large lakes, and provide useful information for decision makers to evaluate established TMDLs and fish consumption advisories.
The Red Creek Consolidated Mitigation Bank and the Challenges of Stream Restoration in Gulf Coastal Plain Soils and Weather
Year: Authors: Maurer B.
Since the Mobile and Vicksburg districts of the Corps began regulating impacts to streams, the Mississippi Department of Transportation has been proactive in acquiring advance credits for future impacts in several watersheds. One such project is the Red Creek Consolidated Mitigation Bank, located in coastal Jackson County and established in partnership with The Nature Conservancy. Approved in 2011, this wetland and stream bank is providing credits on wet pine flats, bayhead and bottomland hardwood forest, and 3,345 linear feet of stream restoration primarily on two reaches of a tributary to Red Creek. The site is part of an ecologically-significant conservation area in the Pascagoula River watershed. The two restoration reaches have distinctive features; a Priority 2 Restoration was completed on steep and highly entrenched section of the upper stream to arrest severe headcutting. In the second reach, Priority 1 stream relocation was completed in a low-gradient bottomland forest to prevent active downcutting. Completed in the spring of 2012, the stream restoration work was subject to several substantial rain storms (including Hurricane Isaac, which dropped 15-20 inches on the site) before soils had settled and vegetation was fully established. In addition, unforeseen seepage areas developed on some of the steeper slopes causing slumping in the toe areas. Significant damage from storms in these seepage areas and later universally throughout much of the project forced a re-evaluation of the design before repairs were completed. This presentation will discuss and contrast the two restoration reaches, including the challenges of choosing Best Management Practices (BMPs)for stream restoration, and establishing vegetation in erodible, relatively low-nutrient soils and unfavorable weather conditions (hot and dry with periodic intense rainfall). Finally, we will evaluate the damage and repairs to restoration reaches, and how the untimely storms quickly taught us what worked best and what needed improvement.
Groundwater Depletion in the Mississippi Delta as Observed by the Gravity Recovery and Climate Experiment (GRACE) Satellite System
Year: Authors: Hossain A.
The Gravity Recovery and Climate Experiment (GRACE), launched in early 2002, is a satellite mission jointly managed by the US National Aeronautics and Space Administration (NASA) and the German Aerospace Center (DLR). Its goal is to map Earth's gravity field with high precision, approximately on a monthly basis. Global representations of Earth's gravity field are produced based on a K-band microwave system, which measures the distance (loosely controlled at about 220 km) between two identical satellites nearly continuously as they revolve in a tandem, near polar orbit, at an initial 485 km altitude. The gravitational effects of changes in atmospheric surface pressure and ocean bottom pressure are removed using numerical model analyses, such that the remaining variability can be attributed primarily to the redistribution of terrestrial water storage, thus provide measurements of column integrated terrestrial water storage (TWS) for the entire globe. Several recent studies clearly demonstrated that GRACE-derived estimates of variations of total water storage (all of the snow, ice, surface water, soil water and groundwater in a region), when combined with auxiliary hydrological datasets, can provide groundwater storage change estimates of sufficient accuracy to benefit water management. This paper summarizes the recent studies that conducted to investigate the groundwater depletion in the Mississippi Delta using GRACE data. This paper also presents the results obtained from the analysis of last ten years monthly GRACE Level 3 data for the Mississippi Delta areas.
Water Depth In An Oxbow Lake-Wetland And Its Influence On Soil Chemistry, Cypress Tree Growth, And Groundwater Recharge
Year: Authors: Lahiri C., Davidson G.R., Threlkeld S.T.
Sky Lake, MS, is an oxbow lake-wetland that was once part of the ancestral Ohio-Mississippi River system. It hosts some of the largest and oldest cypress trees in the state, with several trees exceeding 40 ft in circumference. An elevated boardwalk recently built into the heart of the wetland now allows unique access to the public and has provided a platform for mounting experimental equipment to monitor several environmental parameters pertinent to managing wetlands and water resources. An ongoing study along the boardwalk is currently monitoring changes in water level, water and soil chemistry (pH, Eh, DO, conductivity, temperature), and atmospheric parameters (precipitation, temperature, relative humidity), and relating the data to tree growth (sap flow rates, trunk expansion) and to changes in groundwater level in a monitoring well located inside the meander loop. Preliminary data indicate that both the flow and chemistry of water within the root zone is highly variable over short distances, likely caused by physical heterogeneity created by fallen and buried tree limbs in various stages of decomposition. Substantial changes in soil zone Eh, an indicator of the redox potential that can influence nutrient uptake by plant roots, were observed over time with no significant correlation between measurement locations. This means that single measurements of soil chemistry at point locations in this wetland environment are not necessarily representative of the conditions for the system as a whole. Measurements at multiple locations are required to adequately assess the chemical conditions that contribute to the health of wetland flora. Groundwater levels measured in the monitoring well rose and fell over a several month period corresponding to high and low water levels in the wetland, respectively, suggesting a possible surface-groundwater connection. Digital cameras set up with dendrometer bands are allowing collection of daily changes in the circumference of four different trees that will allow correlation with sap flow and the monitored environmental variables.
Delineation of Watersheds in Northwestern Mississippi to the Sub-Watershed Level
Year: Authors: Rose C.E.
In 2009, river systems in Mississippi were delineated to the watershed level, and most were delineated to the subwatershed level. One of the exceptions was the northwestern part of Mississippi in the lower part of the Yazoo River Basin (locally referred to as the "Delta") where only watershed-level delineations were completed. Watersheds and sub-watersheds previously delineated in Mississippi were based on elevation change and water body locations as observed from topographic maps, digital elevation models, and aerial photographs. Previous attempts to delineate watersheds in the Mississippi Delta region to the sub-watershed boundaries were problematic due to the following issues: topographically-uniform, low relief land elevations (less than 100 feet of rise in land-surface elevation from Vicksburg to Memphis); land management practices employed by land owners and growers who frequently change drainage patterns; and insufficient scale of available elevation to allow delineation of subtle topographic features. Therefore, the Mississippi Delta region was not delineated to the sub-watershed level until more precise digital elevation tools were available for use. Delineation of watershed boundaries and designation of watershed numbering and naming is an important first step for resource managers that are concerned with ecosystem and water body health and remediation of point and non-point source pollution. Previous scientific studies have implicated the Delta region as a contributor to the hypoxic zone in the Gulf of Mexico, and a large percentage of Delta waters are listed as impaired on the section 303(d) List of Impaired Waters. For Delta streams, ecosystem health and mitigation of nonpoint source pollution is a primary concern for resource managers, and delineation of watersheds in this region is a critical and necessary step for future planning and mitigation activities. Since the publication of the Mississippi Watershed Boundary Dataset in 2009, the entire Yazoo River Basin (including the Mississippi Delta region) has been mapped using Light Detection and Ranging (LiDAR) technology (funded by the U.S. Army Corps of Engineers, Vicksburg District), which has a root mean square error vertical land surface bare-earth accuracy of 9 centimeters. With the availability of LiDAR data, it is now more reasonable to delineate the Mississippi Delta region to the sub-watershed level. The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, has completed the delineation of river systems in the Mississippi Delta region to the subwatershed level.
Pathogen Indicator Monitoring in the Ross Barnett Reservoir
Year: Authors: Capps P., Hicks M., Surbeck C.Q.
Man-made reservoirs are often used for both water supply and recreation. The US Environmental Protection Agency's (EPA) recent National Lakes Assessment survey includes water quality concerns for beneficial uses of such man-made reservoirs. The EPA ranks the Ross Barnett Reservoir watershed as the most important in the state of Mississippi and has selected it as a Priority Watershed. The Ross Barnett Reservoir, a 33,000-acre lake, provides drinking water to the city of Jackson, MS, and forty-eight surrounding communities. Further, an estimated 2.5 million people visit the reservoir each year for recreational purposes, including boating, fishing, water-skiing, and swimming. Substantial residential and commercial developments in Madison and Rankin counties along the 105 miles of reservoir shoreline have the potential to affect water quality in the reservoir. Due to the reservoir's important role as a water-supply source, the protection of the water quality in the reservoir is crucial for human health. A collaborative investigation is underway by the University of Mississippi, the U.S. Geological Survey, and the Mississippi Department of Environmental Quality, to assess pathogen indicator concentrations in the Ross Barnett Reservoir. Sources of the pathogens may include stormwater runoff, failing septic systems, lake-bottom sediments, and humans in direct contact with the water. Data for pathogen indicators and other water-quality parameters such as water temperature, pH, dissolved oxygen, conductivity, nitrate, phosphate, and solar strength, were collected at two recreational sites at the reservoir twice a week for 23 weeks through the spring and summer of 2013. Average concentrations for all E. coli, enterococci, and fecal coliform were 264 cfu/100mL, 175 cfu/100mL, and 298 cfu/100mL, and standard deviations for each were 654 cfu/100mL, 249 cfu/100mL, and 952 cfu/100mL, respectively. The concentrations of pathogen indicators and nutrients, and values of physical parameters will be statistically analyzed to provide insight about contamination sources. A review of past monitoring efforts in other related fresh-water lakes will also be reported.
Water quality modeling in the Ross Barnett Reservoir
Year: Authors: Jackson G.
This study presentation investigates the utilization and economic feasibility of hydrodynamic models as tools for assessing factors impacting water quality in the Ross Barnett Reservoir and the Pearl River for nutrient TMDL development. The primary focus is the development steps necessary to create a hydrodynamic model that provides transport information to subsequent application of a water quality model (WASP). Environmental Fluid Dynamics Code (EFDC) is a complex, dynamic, multi-dimensional computer model used to simulate hydrology in water bodies. The hydrodynamic model output feeds directly into the WASP water quality simulation. The secondary focus is on data acquisition and EFDC model manipulation methods for completing the hydrodynamic modeling. Monitoring was completed to create modern bathymetry of Ross Barnett Reservoir to provide accurate model cell grid representation. Temperature and dissolved oxygen profile monitoring were gathered to provide data for model output comparison. The EFDC model successfully predicted lake stratification and subsequent mixing based on changes in observed meteorological conditions. Finally, the model development costs and level of difficulty must be justified to consider broad use of this model development combination for state water quality agencies. EFDC / WASP model development tools that will reduce the development costs are in production, and should improve the usefulness of the EFDC / WASP model combination in the future.
Climate Variability Impacts on Crop and Sediment Yields
Year: Authors: Parajuli P.B., Jayakody P., Sassenrath G.
This study evaluated future climate variability impact on stream flow, crop and sediment yields under three different tillage systems in the Big Sunflower River Watershed (BSRW) in Mississippi. The Soil and Water Assessment Tool (SWAT) was applied to the BSRW using observed stream flow and crop yields data. The model was successfully calibrated and validated and future climate scenarios were simulated. Results showed that there is no significant difference (p > 0.05) between average corn and soybean yields under simulated tillage systems in the BSRW. However, results determined a significant difference on sediment yields from three simulated tillage systems (p values of 0.002 for corn, and 0.003 for soybean). The model simulated results showed that future average maximum temperature may increase and experience a longer summer periods with frequent extreme rainfall events but similar monthly precipitation patterns.
A STELLA model for estimating phosphorus removal from wastewater in a vertical-flow constructed wetland system
Year: Authors: Ouyang Y.
Elevated phosphorus (P) in surface waters can cause eutrophication of aquatic ecosystems and can impair water for drinking, industry, agriculture, and recreation. Vertical flow constructed wetland (VFCW) can purify P contaminated wastewaters before they discharge into streams and rivers. The goal of this study is to develop a model for predicting the fate, transport, and removal of P from wastewaters in a VFCW using the commercial available STELLA (Structural Thinking, Experiential Learning Laboratory with Animation) software. The VFCW used in this study consists of soil and plant species with variably saturation conditions such as wetting (ponding) and drying (draining) cycles. The water movement through the soil, xylem, and surrounding atmosphere in the VFCW system is calculated using water potential theory, whereas the fate and transport mechanisms of P used in this model include: (1) application of wastewater (containing P) to the VFCW; (2) adsorption of P in the soil; (3) uptake of P by plant roots, (4) mineralization of organic P; and (5) leaching of soluble P. Additionally, the surficial processes such as rainfall and evapotranspiration are included in the model. The resulted model is calibrated and validated with experimental data prior to its applications. A simulation scenario is then performed to estimate P removal from a domestic wastewater in the VFCW system under varying hydraulic retention times. Simulation results will be presented and discussed.
Quantification of Harmful Algal Blooms (HABs) in the Grand Bay in Jackson County, MS
Year: Authors: Dampier J., Dash P., Begonia M.F.
Harmful Algal Blooms (HABs) are caused by species of tiny plants, phytoplankton. HABs may cause harm through the production of potent chemical toxins or by their accumulated biomass. Impacts include massive fish kills, loss of sales revenue primarily from fisheries and tourism, loss of commercially valuable and culturally vital shellfish resources, illness and death in populations of protected marine species, and threats to human health. Among the many HAB impacts in the northern Gulf of Mexico, those due to coastal blooms of the diatoms genus Pseudo-nitzschia with its associated toxin domoic acid, and the dinoflagellates of the genus Karenia with its associated toxin brevetoxin are of particular concern. This work (a field, laboratory and satellite remote sensing research) focused on quantifying HABs in the Grand Bay. It encompasses the collection of field data which is analyzed in the laboratory for pigments, suspended sediments, dissolved materials, and toxins as well as a satellite remote sensing component focused on developing techniques for mapping HABs from space. Recently, a procedure was developed to estimate cyanobacterial concentrations by quantifying chlorophyll a and the primary cyanobacterial pigment phycocyanin using OCM satellite data. This required the development of an atmospheric correction and vicarious calibration methodology for satellite data in inland and coastal waters. It has been tested to work for data from several satellite sensors such as OCM, SeaWiFS, MODIS, MERIS and QuickBird. This research is focused on use of satellite sensors, NPP VIIRS and MODIS AQUA, and the developed techniques to quantify HABs in the Grand Bay. In addition to algal toxins, the toxicity of environmental pollutants (i.e., heavy metals such as Pb, Cd, etc.) in the water was investigated and the mutual relationships between the heavy metals and HABs will be examined. This research will enhance the current state of knowledge on detection and mapping of the HABs in the Grand Bay and thus support state and coastal community efforts to manage fisheries in the region.
Groundwater Level Forecasting in Sunflower County, Mississippi using Artificial Neural Networks
Year: Authors: Guzm S., Paz J.O., Tagert M.L.
The Mississippi Delta Region is one of the most important in the United States given the high productivity levels of crops such as corn, cotton, rice, and soybean. Most of these crops require supplemental irrigation to sustain yield and to reduce the impacts of extended periods of dryness during the growing season. Due to the expansion of croplands , the annual volume of groundwater withdrawals have increased dramatically over the past two decades, exceeding aquifer recharge and generating an important reduction in the aquifer levels. In this study, we present the preliminary groundwater level simulation results for a well in Sunflower County that is within the Mississippi River Valley Shallow Alluvial (MRVA) aquifer. The performance of two different artificial neural networks (ANN) for groundwater level forecasting was evaluated in order to identify an optimal architecture that can simulate decreasing trends of the groundwater level in summer season. Two algorithms, Levenberg-Marquardt and Bayesian Regularization, were evaluated in order to obtain a model that shows better results in the simulation of changes in groundwater level and provide acceptable predictions up to 3 months ahead. The ANN predictive performance was assessed based on the comparison between Root Mean Square Error (RMSE) for each algorithm. Neural networks learn and recognize patterns in the nonlinear temporal data through mathematical analysis and computational architecture inspired by how the human brain works given a set of examples. This methodology is a tool to predict in a short period of time, groundwater levels at specific control points that would be used in an optimized regional plan to manage water withdrawals, and help farmers and water managers decide how to implement plan control procedures and conservation practices.
Evaluating the impacts of crop rotations on groundwater recharge and water table depth in the Mississippi Delta
Year: Authors: Dakhlalla A.O., Parajuli P.B.
The Mississippi River Valley Alluvial Aquifer (MRVA), which underlies the Big Sunflower River Watershed (BSRW), is the most heavily used aquifer in Mississippi. Because the MRVA is primarily used for irrigating crops such as corn, cotton, soybean, and rice, the water levels have been declining rapidly over the past few decades. Each crop rotation practice demands certain irrigation amounts and applications, which in turn can affect the hydrogeology of the aquifer. The objective of this study is to assess the impacts of crop rotation practices on groundwater recharge rates and water table depths in the BSRW using the Soil and Water Assessment Tool (SWAT) model. The SWAT model was hydrologically calibrated for monthly streamflow using observed streamflow data from 3 USGS gage stations (Merigold, Sunflower, and Leland). Because this study focuses on groundwater processes, the model was also calibrated for water table depths at several ground water wells throughout the BSRW. The observed water table depths used to calibrate the model were provided by the Yazoo Management District (YMD). The model was evaluated based on the coefficient of determination, Nash-Sutcliffe Efficiency, and root mean square error statistics. The crop rotation scenarios that will be employed in this study are corn after soybean, soybean after rice, and continuous soybean. This study will provide some insight into which crop rotation practices cause the most fluctuations on groundwater recharge and water table depths.
Identifying A Mechanism For An Infiltration Threshold From The Sunflower River, MS To The Underlying Alluvial Aquifer
Year: Authors: Patton A.C., Davidson G.R., Rigby J.R., Barlow J.
Long-term groundwater level and river stage measurements at a USGS coupled groundwater stream-gaging station located on the Sunflower River at Sunflower, MS show an apparent stage-threshold for infiltration to the underlying alluvial aquifer. This site is located near the center of a large regional cone of depression in the Mississippi River Valley alluvial aquifer and therefore provides insight into the effects of groundwater declines on streamflow in the Big Sunflower River. Groundwater levels respond to changes in river stage only when river stage exceeds 34 m msl (mean sea level). The purpose of this research was to identify the responsible mechanism. Two hypotheses were considered: (1) scour of infiltration-limiting fine-grained bottom sediments during high flow rate events at higher stage, and (2) lateral infiltration at high stage into more permeable coarser grained sedimentary layers intersecting the stream channel at higher elevation.
Empirical evidence of recharge in the Mississippi Alluvial Aquifer
Year: Authors: Johnson D.R., Barlow J.
Multiple groundwater models have been constructed to model the alluvial aquifer. These models differ significantly in the allocation of water for recharge. This paper will examine the potential sources of recharge and estimate their magnitudes. Other literature will be used to validate the assumptions presented in this paper.
National Weather Service Flood Surveys & Post-Event Analysis of Hurricane Isaac
Year: Authors: Lincoln W.S.
After the substantial impact to the United States East Coast from Hurricane Sandy, Hurricane Isaac may become the forgotten hurricane of 2012. With its above average size and slow forward motion, Isaac produced higher storm surge than typically seen by a storm of its wind category, and also dropped notably heavy rainfall across portions of southeast Louisiana and south Mississippi. Over a four day period from August 28th to August 31st, rainfall totals ranged from 10-15 inches across most of the area, with a few areas seeing more than 20 inches. This significant rainfall caused flooding of numerous rivers in the forecast area of the National Weather Service (NWS) Lower Mississippi River Forecast Center, especially areas within the county warning area of the New Orleans/Baton Rouge Weather Forecast Office. Because of the rare nature of the event, a team composed of NWS staff from multiple offices was assembled to record the impacts, survey flood crests when necessary, and discuss the event with local residents. Post-event flood surveys were conducted over a number of days in early September, 2012, particularly across the Wolf, Tchoutacabouffa, Biloxi, and Escatawpa River watersheds in Mississippi and the Tangipahoa River watershed in Louisiana. A vast amount of observations, anecdotal data, and recommendations were collected by the survey teams and summarized in a report for the River Forecast Center and the Weather Forecast Office. Flooding of numerous locations was of a magnitude seen only on very rare occasions and may have been the worst flooding yet-experienced by numerous long term residents. Luckily, due to the sparse population density in most of the river floodplain areas, impacts were not as severe as would typically be expected. Findings from the post-event flood surveys and analysis of data from numerous sources will be presented to further our understanding of Isaac's hydrologic impact.
The Role of Long-term Monitoring In Understanding Phosphate Spills Into A National Estuarine Research Reserve
Year: Authors: Cressman K., Woodrey M., Ruple D.
Grand Bay National Estuarine Research Reserve (GBNERR) is an 18,400-acre protected area in southeastern Jackson County, MS. The GBNERR, along with 27 other Reserves, collects long-term environmental data, including water quality, weather and nutrient parameters, following accepted national protocols as part of a System-Wide Monitoring Program (SWMP). In 2005, a phosphate facility on GBNERR's western border released wastewater into Bangs Lake. Data from SWMP were used to help determine the timing and duration of the event. The pH measured by a data logger deployed at the Bangs Lake water quality station dropped to 3.7. Orthophosphate, tested monthly in the water column and usually below the detection limit of 0.01 mg/L, spiked to over 4 mg/L: more than 400 times higher than normal. PO4 concentrations returned to baseline levels after Hurricane Katrina and remained below 0.01 mg/L until September 2012, when Hurricane Isaac led to another release into Bangs Lake. Routine nutrient sampling three weeks after Isaac found phosphate levels over 1 mg/L in Bangs Lake. Phosphate was also high at further distances from the plant. As of December 2013, other stations' water column phosphate concentrations had returned to normal, but phosphate in Bangs Lake remained higher than historical levels. Research by collaborators at nearby institutions has helped fill in details of the magnitude and spatial patterns of the 2012 spill. This work, combined with the long-term context of SWMP data, led to the formation of a Phosphate Working Group, which will continue to explore the ecological effects of this long-term addition of phosphorus to Bangs Lake.
Investigating the Water Quality of Four Large Mississippi Lakes and Grand Bay, MS-AL Gulfcoast
Year: Authors: Dash P., Ikenga J.O., Pinckney J.L.
Harmful Algal Blooms (HABs), harmful microorganisms, and toxic metals represent three main water quality deteriorating agents in the water-bodies. The objectives of this research were to take a systems level approach to investigate the water quality of four large Mississippi freshwater lakes including lakes Sardis, Enid, Grenada and Ross Barnett Reservoir and the Grand Bay in Mississippi Alabama gulf coast. Ten field campaigns were undertaken to the freshwater lakes and six sampling trips were organized to the Grand Bay to collect water samples, to measure the physical parameters including temperature, salinity, dissolved oxygen and pH, to measure remote sensing reflectance and backscattering at twelve discrete sites in each of the water bodies. The water samples were collected for high performance liquid chromatography (HPLC) photopigments, colored dissolved organic matter (CDOM), suspended particulate matter (SPM), phycotoxins, nutrients, absorption, bacterial counts, toxic metals, and microscopy analyses. In all these water-bodies, organic SPM surpassed its inorganic counterpart, which indicates that organics have a bigger share in the water quality deterioration in these systems. The photo-pigments derived relative abundances of major algal groups suggested the abundance of cyanobacteria, diatoms and dinoflagellates in all these systems. An investigation of the species composition will reveal the detail community structure. Phycotoxins and several types of bacteria and toxic metals were found in all the water bodies. The observation of these water quality issues warrants continuous operational monitoring of the water quality, investigation of fate and transport of pollutants, and implementation of best management practices for all these water-bodies.
Flow Characteristics of Selected River Basins in Mississippi
Year: Authors: Runner M.
The U.S. Geological Survey has been collecting stage and flow data at select locations in Mississippi for more than 100 years. The first data collection station was built on the Tombigbee River at Columbus in 1895. Currently, continuous flow data are collected at more than 70 locations and instantaneous peak flow data at an additional 95. Stage and flow data have many uses and serve a variety of purposes filling a valuable need for both governmental agencies, academic institutions, and the general public at large.<br /><br />There are many benefits to a stable streamgaging program including resource management, flood operations of structures, and flood forecasting. Most of these benefits are derived from access to current flow data, but there are benefits from long-term data sets that are not as readily apparent. One of these is the ability to use these data to detect trends in flow characteristics over time. <br /><br />This report presents statistical summaries for data sets of select gages near the mouth of major river basins in Mississippi. Data for the Tombigbee, Chickasawhay, Leaf, Pascagoula, Yazoo, Big Black, and other select rivers are presented.
The Effects of Weirs on Vegetation Communities in Agricultural Drainage Ditches of the Mississippi Alluvial Delta
Year: Authors: Shipes C., Kröger R.
Drainage ditches in the Mississippi Alluvial Delta are an essential part of the agricultural landscape of this region. These ditches vary greatly in size, location, and shape, but can aid in mitigation of contaminants from agricultural fields. Historically controlled drainage in the form of slotted or drop pipes, flash board risers, and vegetated drainage ditches have been used to effectively manage nutrients. More recently low-grade weirs have been used as an alternative to traditional controlled drainage structures. Low- grade weirs act to slow water flow, increase residence time, and allow sedimentation. Until recently the relationship between low-grade weirs and the vegetation communities present has not been evaluated. We selected 13 agricultural drainage ditches with weirs present in the Mississippi Alluvial Valley and investigated the vegetation community responses to weirs and weir age. We also selected 4 control ditches with no weirs present to compare our results. Vegetation assessment yielded 41 plant species ranging from obligate wetland plants to facultative upland plants. Simple correlation tests showed a strong positive relationship between weir age and species diversity, and also a positive correlation between total percent vegetative coverage and weir age. Linear regression also showed a positive relationship between weir age and the presence of facultative upland plants and a negative relationship between weir age and the presence of obligate wetland plants. This study shows some interesting trends, but we were limited in our sample size. Future studies should focus on a larger sample size with a wider range of age classes and should take other variables into account such as; vegetation communities upstream, slope of individual ditches, the spatial arrangement of weirs within the ditch system, and association with other weirs within the same ditch system.
The Effects of Weirs on Macroinvertebrate Communities in Agricultural Drainage Ditches of the Mississippi Delta
Year: Authors: Feaga J., Kröger R.
Drainage ditches are an essential part to effective agricultural production by regulating water levels to control the inundation of production acreage. Drainage ditch construction in the Mississippi Delta, was merely a response to the need for access to more fertile soils, which previously was dominated by bottomland hardwood forests, oxbow lakes, and cypress swamps. Various ditches within the Mississippi Delta system contain weirs, which function to limit nutrient export into downstream habitats by reducing flow of water and increasing residence time. Until relatively recently, the biological significance of these agricultural structures to macroinvertebrate communities was not entirely understood. We investigated patterns of communal macroinvertebrate composition within seven agricultural drainage ditches with weirs near Belzoni, Mississippi. We examined macroinvertebrate abundance responses to weir age and distribution patterns with respect to distance from weirs. We then compared these results to results observed in 3 control ditches without weirs. Macroinvertebrates sampled from 7 ditch sites represented 11 distinct taxa with a total abundance of 3,948 individuals. The main contributors to total abundances were Chironomidae (48%), Physidae (30%), and Oligochaeta (20%) with Physidae (43%, n = 876) and Chironomidae (66%, n = 1905) representing the largest relative abundances in treatment and control ditches, respectively. Simple correlation tests showed macroinvertebrate abundances are not significantly influenced by either weir age or distance from weir. Our study suggests further investigation is needed to accurately assess the functional response of macroinvertebrate community composition to weirs. Our study was limited in both sample size and time. These limitations prohibited us from making significant conclusions about our results. We suggest a longitudinal study with a larger sample size across a wider pool of age classes may produce statistically significant results.
Soil Media Compositions for Water Quality Improvements and Stormwater Management in Urban Flow-through Facilities
Year: Authors: Kröger R., Gallo C., Overbey E.
Nutrient removal and volume reduction capabilities of a range of soil media mixtures in urban flow-through planters were investigated. Eighteen scaled flow-through mesocosms were evaluated for nitrogen and phosphorus removal rates and volume reduction by applying a synthetic stormwater solution over a simulated 2-inch, Type II storm hydrograph. Three replicates of six treatments were tested including four soil mixtures. Significant (p<0.05) reductions in volume for 100% sand, 75% sand, 50% sand content mesocosms compared to the controls, indicating bioretention mixes with higher sand content have greater water retention capabilities. For water quality results, both concentration and load reductions were calculated and compared, where load accounted for volume passing through the mesocosms and therefore more accurately represented water quality results. PO4 load reduction was greater in treatments with less sand (up to 41% reduction). NO<sub>3</sub>-N load reduction varied greatly (7% removal to 53% loading). Significant phosphate loading was observed at the peak of the hydrograph (between minutes 60 and 120) compared to the controls, indicating greater flow rates decreased the nutrient removal capabilities of bioretention in the experiment. Preferential flow patterns were observed which potentially led to higher than expected infiltration rates and therefore no observable peak flow reduction.
Comparisons of Indigenous and Selected Bacterial Degrading Pentachlorophenol (PCP) Consortiums for Remediation of PCP Contaminated Groundwater
Year: Authors: Prewitt M.L., Borazjani H., Willeford K.
Results from this research are expected to reveal which of 3 consortiums of bioaugmented PCP degrading bacteria will increase PCP degradation in contaminated groundwater. The information that will be gained from this research should lead to customizing remediation methods based on the indigenous microbial community at a contaminated site. Not only could bacterial consortiums be used for PCP degradation, they could also be used to address other water quality issues such as high Biological Oxygen Demand (BOD) that impacts wastewater discharge from industries in Mississippi and nationwide such as the pulp and paper mills, oil spills in the Gulf Coast and excess nitrogen in agriculture runoff.
Ecological Assessment of NRCS's Migratory Bird Habitat Initiative in Reponse to BP's Gulf Oil Spill
Year: Authors: Kaminski R.
Science should guide conservation of natural resources to promote effectiveness, efficiency, and economy of management actions and policy development. Following the Deepwater Horizon Oil Spill in the Gulf of Mexico in April 2010, the Natural Resources Conservation Service (NRCS) established the Migratory Bird Habitat Initiative (MBHI). Working with owners and managers of private croplands, aquaculture ponds, and Wetland Reserve Program easements, NRCS and conservation partners managed thousands of acres of wetlands and agricultural lands in the Mississippi Alluvial Valley (MAV) and Gulf Coast regions to provide wetland and upland habitat inland from potentially oil-impacted coastal wetlands. In fall 2010, scientists and graduate students from Mississippi State University, Arkansas Tech University, and University of Missouri began designing and implementing local and landscape scale surveys to (1) estimate use of MBHI managed wetlands and comparable non-MBHI wetlands by shorebirds, waterfowl, and other waterbirds, and (2) assess relative effectiveness of different MBHI practices for providing habitat and food resources for migrating, resident, and wintering waterbirds. Currently, researchers are working in the MAV in Arkansas, Louisiana, Mississippi, and Missouri and the Gulf Coast Prairies in Louisiana and Texas. Our presentation will summarize estimated bird use and food abundance on MBHI and compared study areas and report future directions for completing the MBHI assessment by 2013. Generally, avian abundance and diversity have been greater on MBHI-managed than other areas, although complexes of managed and other wetlands are providing wetland habitat for waterbirds among seasons. For example, when managed wetlands are dewatered in spring-summer to promote emergent vegetation, wetlands lacking such hydrological management provide habitat for waterbirds. Our study will aid future habitat conservation and adaptive management on private and public lands inland from the Gulf, which is a proactive need considering continued decline of continentally important coastal wetlands.
Support for a Northeast MS Regional Water Management Plan: Updating the Water Budget for the Tombigbee River Basin
Year: Authors: Ramirez-Avila J.J., McAnally III W.H., Tagert M.L.
Researchers from Mississippi State University (MSU) are providing assistance to organize and draft a water management plan for selected northeast Mississippi counties, in the context of an overall basin plan, with the guidance and support of the Tennessee River Valley Water Management District (TRVWMD) and its stakeholders. Updating the MSU water budget for the Tombigbee River Basin developed by McKey and McAnally in 2008 is one of the main tasks included in the statement of work for the study in performance. Research activities to complete the proposed task involves the consecution of new information on withdrawals and discharges; the use of hydrologic calculations to fill in gaps of ungaged streams in the basin and identify potential extreme flows; and the statistical analysis of flow data for use in a risk analysis of extreme flows.
Efficacy of Innovative Surface Water Capture and Irrigation Re-use Technologies as a Best Management Practice: A Multi-seasonal Assessment in the Mississippi Delta Region
Year: Authors: Omer A., Kröger R.
The Mississippi Alluvial Valley is the center for agricultural crop production in the Southeast United States. The necessity for irrigation to maintain maximum yields has led to increased pressure placed on the Mississippi Alluvial Aquifer resulting in a negative balance. As a method of water management, surface water capture and irrigation re-use systems are being implemented into agriculture systems in Mississippi. However, the environmental and economic benefits of these systems have yet to be described and quantified. The main objective of this research is to describe and quantify the potential benefits of surface water capture and irrigation re-use systems for water resource conservation. Four sites located in the Mississippi Delta Region which utilize water capture and irrigation re-use systems will be assessed by monitoring: pumping schedules of re-lift stations, water level of on-farm storage reservoirs and flows of surface water irrigation pumps through irrigation meters. This data will be compared to systems using strictly ground water to understand water saving differences. Three years of data will be used to quantify a water savings budget and assess at a regional scale the contributions of surface water capture to decrease ground water withdrawals. The water savings budget in addition to the potential energy savings will be combined to provide an economic analysis of water capture and irrigation re-use systems. The results of this research will be used to create an economic analysis to provide valuable outreach material for dissemination to Mississippi producers. This potentially will lead to further implementation of water capture and irrigation re-use systems throughout Mississippi.
Modeling Rainfall Runoff using 2D Shallow Water Equation
Year: Authors: Shirmeen T., Jia Y.
Torrential storms often trigger flooding that causes damage in properties and loss of life. In this study a numerical simulation module is developed to enhance the capability of a 2D surface flow model, CCHE2D. Following the procedure for numerical model verification and validation of ASCE, the developed module is tested using both analytical solutions and experiment data. <br /><br /> The analytical solutions of kinematic wave equation for runoff occurring on a sloping plane subject to a constant rainfall of indefinite duration and finite duration were used to compare to the results of the numerical model with good agreements. Runoff processes measured in laboratory experiments were also simulated in this study using the 2D model. The simulated runoff processes and the observed physical processes again showed excellent agreements. These tests indicate that the CCHE2D model is capable of modeling rainfall-runoff and kinematic overland flows.
Crayfish Harvesting: Alternative Opportunities for Landowners Practicing Moist-soil Wetland Management
Year: Authors: Alford A.B., Grado S.C., Kaminski R.M.
Harvest of crayfish (<em>Procambarus</em> spp.) for human consumption in the United States and beyond is considerable, amounting to an annual value of $150-170 million annually in the southern United States alone. Most crayfish harvested for human consumption are cultivated in rice fields in southern Louisiana. Management of emergent vegetation in moist-soil wetlands is similar to cultivation of rice where the seasonal wet-dry cycle of these wetlands encourages the growth of annual plants that produce abundant seeds and tubers for waterfowl forage. Recent aquatic invertebrate studies in moist-soil wetlands suggest that populations of crayfish in these habitats may be large enough to warrant a harvest for human consumption. To estimate the economic potential of crayfish harvests in moist-soil wetlands, crayfish yield was estimated from moist-soil wetlands on public and private lands in the MAV in Arkansas, Louisiana, Mississippi, and Missouri in spring-summer 2009-2011 using typical crayfish harvest strategies practiced in commercial rice-crayfish fields of Louisiana. Average daily yields of crayfish from moist-soil wetlands ranged from 0.08 kg/ha to 23 kg/ha with an overall mean yield of 2.73 kg/ha (n = 42, CV = 21%). Whereas the mean daily yield of crayfish from moist-soil wetlands was >3 times less than the yield expected from a high production rice-crayfish culture system (e.g., 8-10 kg/ha), estimated cost associated with harvest of crayfish from moist-soil wetlands were $529/ha and were lower compared to costs associated rice-crayfish harvest practices which were estimated to be $1,856/ha. However, the estimated break-even selling price for crayfish harvested from moist-soil wetlands was $4.90/kg compared to $2.75/kg estimated for rice-crayfish practices. The estimates of break-even selling prices for crayfish harvested from moist-soil wetlands were higher than the 2012 estimate of $2.75/kg price for single crop production of crayfish in Louisiana. However, in areas where crayfish markets are sparse, such as the North Mississippi Delta, landowners may still realize economic potential from this fishery. Harvesting crayfish from moist-soil wetlands may provide a small profit to landowners but will likely provide additional recreational opportunities and can serve as additional extension vehicles to encourage wetlands conservation throughout the MAV.
Rivers and Community Engagement. Regulatory Frameworks and Practices in Europe and USA.
Year: Authors: Pappalardo G.
Environmental regeneration is not just a matter of natural science. Laypersons, different stakeholders, associations such as NGOs are crucial actors in managing ecosystems, at the grassroots level as well as at the institutional level. Gunderson, Holland et al (1995) describe the relationship between human organizational structures and nature, underlying how Sustainable Development is a process related to Social Learning. Even if the expressions Sustainable Development and Social Learning may have ambiguous meanings related to every different context, it is possible to find some similar issues at the global scale. The U.N. Rio Declaration on Environment and Development (1992) and its updated version Rio+20 show an arising awareness about the crucial role of local communities in taking care of the environment. Moreover, the Nobel Prize in Economic Science Elinor Ostrom (1991) proves the importance of collaborative practices and institutional reframing in order to overcome the Tragedy of the Commons (Hardin 1968).<br /><br /> This paper is aimed at describing and characterizing the process of Community Engagement in watershed management in Europe and USA. First, a critical review of the regulatory frameworks is examined, in order to explain similarities and differences between these two contexts. In Europe, the Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters (1998) is a milestone on the topic; then, the European Landscape Convention (2000) explains the strong relationship among physical heritage, cultural dimensions and inhabitants' perceptions. Furthermore, the specific Directive in matter of Water (2000/60/EC) is based on the same principles, i.e. broad involvement of the general public and different stakeholders, with different knowledge, values, interests and future perspectives. In U.S.A. the Environmental Protection Agency, with the Clean Water Act (1972) and 40 years of implementation phases, is moving the discussion toward a broader dissemination of participatory practices (Sirianni 2006).<br /><br />After a comparative analysis of the aforementioned regulations, a multiple case-study research is discussed in order to understand in practice what is engagement, how is it related to watershed management, which are different paradigms and types of community involvement. The cases are selected according to the following characteristics: engagement as an opportunity to define a common vision for the future, starting from history and values of every context; engagement as a way to promote education and responsible behaviors in managing the water; engagement as a moment of dialogue amongst all community members. The outcome of the research is a typology that may operate as a guide in organizing communities that wish to manage ecosystems in a proactive and adaptive way.<br /><a href="/pdf/2013_pappalardo_pres.pdf">Download the presentation</a>
Modeling the Potential for Water Supply from a Constructed Lake in South Mississippi Under Present Climate and Projected Climate Change
Year: Authors: Pote J.W., Wax C.L., Tagert M.L.
The daily volume of water in a 5200 acre lake with a full capacity of 104,000 A-F in a coastal Mississippi location is simulated from 1961-2010. The lake basin is 17,550 acres, a runoff coefficient of 0.7 is used, base flow is set at 3 A-F/d, infiltration rate is set at 12 A-F/d, and outflow is set at 3 A-F/d. Inputs from the present climate regime are precipitation (P) minus potential evaporation (PE). Positive daily P-PE adds water to the lake and daily negative P-PE subtracts water from the lake. Climate change is projected by reducing daily P by 1.57% and increasing daily PE by 9.73%.<br /><br /> Cumulative P-PE for the average of all 50 years, the wettest year (1961), the median year (1993), and the driest year (2000), with and without climate change, is calculated. Factoring in the daily interaction between P and PE and comparing the present and changed climate by graphing the cumulative effect through the year shows that the annual pattern stays relatively the same day-by-day through each of the years and that the modeled climate change does reduce the end result in each of the years. For example, the average curves in both graphs show that under present climate the year ends at 19.77" but with climate change it ends at 13.85", a reduction of 5.32" or about 28% of the extra water. The median year curves show that without climate change the year ends at 24.55" but with climate change it ends at 19.75", a reduction of 4.8" or about 20% of excess water. The wettest year curves show the year ending at 54.65" but with climate change it ends at 48.40", a reduction of 6.55" or about 12% of extra water. The driest year curves show the year ending at -10.93" but with climate change it ends at -15.97, an increase in the year's deficit of 5.04" or about 46%. <br /><br /> Even in light of these potential changes in the average and extreme years, a 50-year daily analysis shows that both without and with climate change, the lake's volume drops no lower than about 97,000 A-F at any point in the period. The conclusion is that the climate of coastal Mississippi will sustain a surface water supply from a lake through known climate variability and proposed climate change in the future.
Design and Construction of Quarry Capture Prevention BMPs on the Buttahatchie River
Year: Authors: Maurer B.J.
Alluvial deposits <em>(Holocen)</em> have made the harvest of sand and gravel profitable in the Buttahatchie River watershed. Historically, excavations in and adjacent to the river have altered the location and stability of the channel. Many inactive, pre-regulation quarries are still found concentrated along the lower 20 km of the main channel. Construction of the Tennessee-Tombigbee Watershed, of which the Buttahatchie River is a tributary, and the resultant head-cutting, have further exacerbated the process of "quarry capture", whereby the river channel changes course into a quarry. <br /><br /> With partners from Mississippi State University, and with support from the US Fish & Wildlife Service, The Nature Conservancy has undertaken a project to develop and implement stabilization BMPs to prevent further quarry capture on the Buttahatchie River. Utilizing LiDAR mapping of the area and modeling of flow patterns, this project will identify points vulnerable to quarry capture, and design and construct appropriate stabilization techniques. Techniques are expected to be both specific to the individual characteristics of each site, and exportable to vulnerable channels in other watersheds. <br /><br /> Construction on the first stabilization project will be completed in the winter of 2013 in Monroe County, Mississippi, and will stabilize 1300 feet of river bank to prevent the river from changing course into several inactive gravel quarries adjacent to the river. This presentation will detail the project design, the selection of BMPs, the construction, and the outcome of the project. The BMPs will include bendway weirs, locked logs, and customized planting installed under very difficult conditions.
Decision analysis for species preservation under sea-level rise
Year: Authors: Linhoss A.C., Kiker G.A., Aiello-Lammens M.E., Chu-Agor M.L., Convertino M., Munoz-Carpena R., Fischer R., Linkov I.
Sea-level rise is expected to dramatically alter low-lying coastal and intertidal areas, which provide important habitat for shoreline-dependent species. The Snowy Plover (Charadrius nivosus) is a threatened shorebird that relies on Gulf Coast sandy beaches for nesting and breeding. Selecting a management strategy for the conservation of this species under sea-level rise is a complex task that entails the consideration of multiple streams of information, stakeholder preferences, value judgments, and uncertainty. We use a spatially explicit linked modeling process that incorporates geomorphological (SLAMM), habitat (MaxEnt), and metapopulation (RAMAS GIS) models to simulate the effect of sea-level rise on Snowy Plover populations. We then apply multi-criteria decision analysis to identify preferred management strategies for the conservation of the species. Two decision analysis techniques are compared: Multiple Attribute Utility Theory and Stochastic Multi-criteria Acceptability Analysis. We investigate four conservation strategies including no action, beach nourishment, nest exclosures, and predator management. Results show that predator management and nest exclosures are the most promising conservation strategies. This is an innovative method for planning for sea-level rise through pairing a linked modeling system with decision analysis to provide management focused results in an inherently uncertain future.
Risk Assessment for Phosphorus Movement in Nutrient Management Planning in Mississippi
Year: Authors: Oldham J.L., Ramirez-Avila J.J., Kingery W.L., Jackson W.
Nutrient Management develops blueprints for using the right amount of the right nutrient source at the right time in the right place. Using poultry litter as a nutrient source in pastures and forages results in increased soil test phosphorus (STP) levels when applications are based on crop nitrogen needs because more phosphorus (P) is provided in each unit of litter than the corresponding unit of grass removes. Increased STP in combination with site-specific soil and field characteristics may lead to P enrichment of surface and ground water. Phosphorus Indices (PI) are state-specific, site-specific algorithms to assess potential P loss that are used in the Nutrient Management Planning (NMP) process. These tools have been developed by individual state Natural Resource Conservation Service (NRCS) agencies under national policy guidance and integrated into the NRCS 590 Nutrient Management Conservation Standard since the late 1990's. Source factors such as STP, and nutrient source and management are used in combination with transport factors including soil characteristics, landscape characterization, and distance to nearest stream in various models to determine relative risk of P movement. Because of the leeway provided to the states, there are numerous versions of PI. Some are quantitative and predict P loss amounts; others, including Mississippi, are qualitative and assign relative risk. With higher risk of P movement to water as determined by PI categories, NMP preparation should assess potential mitigating Best Management Practices adoption. At issue are two recent published southern regional efforts that found differences in PI prediction capacity between state versions, including Mississippi. Individual state NRCS agencies, in cooperation with in-state partners, were asked to update their Nutrient Management Practice Standards in 2012, including reassessment of each state Phosphorus Index. In addition to the in-state standard revision with Mississippi NRCS, Mississippi State University is participating in a multistate effort under the national NRCS Conservation Innovation Grants to coordinate and advance P management in the southern region, ensuring that the PI have been tested based on new guidance in the NRCS 590 standard, and that tools produce more consistent results across physiographic regions in order to promote better consistency between southern state recommendations. This paper provides an overview of NMP, the factors used in the Mississippi Phosphorus Index, and additional efforts regarding NMP process in Mississippi.
Effectiveness of low grade weirs to reduce sediment and nutrients loads in agricultural ditches of the Mississippi Delta
Year: Authors: Ramirez-Avila J.J., Poganski B., Kröger R.
Drainage ditches are an essential component of the agricultural landscape. Ditches mediate the flow of pollutants from agroecosystems to downstream water bodies. Low-grade weirs established along drainage ditches, as an agricultural best management practice, have been evaluated as an effective measure to mitigate nutrient and sediment loads to downstream aquatic systems. A study was performed to estimate sediment and nutrient loading reductions and to determine the cost-effectiveness curve of implementing low grade weirs in agricultural drainage ditches systems in the Mississippi Delta. The study goals were addressed by combining field data collection and computational modeling techniques. Runoff volumes flowing downstream of low grade weirs along different drainage ditch systems during stormflow and irrigation events were estimated by using the Hydrologic Engineering Center - River Analysis System (HEC-RAS 4.1) model. Monitored sediment and nutrient concentrations and the generated runoff flows were used to develop representative rating curves for each low grade weir on each drainage ditch system. Runoff hydrograph flows on each event were routed through the generated rating curves to estimate instantaneous and total sediment and nutrient loads at each location. Loads were compared to determine low grade weirs efficiency inside each drainage ditch and between drainage ditch systems. A second part of the study used the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN 1.2) to determine the most cost-effective solutions for meeting proposed agricultural runoff water quality conditions. Results from this study will provide more insights to further enhance the nutrient reduction strategy within the Mississippi Delta region.
Variable spatial and temporal impacts of low-grade weirs on the agriculture landscape: evaluating the costs and benefits
Year: Authors: Poganski B., Kröger R., Pierce S.
The use of inorganic fertilizers in agricultural production is widely recognized as a source of nitrate contributing to annual hypoxic zones in the Gulf of Mexico. Ecosystem degradation and impacts on freshwater and marine biota from nutrient contamination of surface waters have motivated research efforts to develop and implement innovative nutrient management practices. Such efforts have become a major priority of many landowners, natural resource conservationists, scientists, and government agencies from a local to national scale. The current experiment investigates how frequency and variable spatial arrangements of best management practices (BMPs) within drainage systems impact water quality leaving the agricultural landscape over time. Preliminary water quality results highlight temporal nutrient trends in agricultural effluent, where concentration spikes were observed during seasons that experience heavy rainfalls and when fertilizer application occurs. Results also showed phosphorus concentrations to be higher in run-off during stormflows rather than during baseflows, while nitrate concentrations in run-off were found to be similar regardless of flow regime. Integrating nutrient reduction data, spatial and temporal variables of best management practices, drainage acreage, and fertilizer inputs will help determine factors that affect nutrient reduction efficiencies and drive the adaptation of management strategies to further enhance pollution mitigation. Investigations of nutrient reduction data and environmental factors highlight the short-term benefits of management practices, which include water conservation, pollution reduction, and ecosystem services. Recognizing that decreasing the loss of water resources and nutrients through BMPs may have additional long-term environmental and monetary benefits to all stakeholders from local to regional scales.
Discerning BMP effectiveness for nutrient reductions in the Mississippi Delta
Year: Authors: Kröger R., Hicks M., Prevost D., Thornton K.
There is a significant impetus within the Mississippi River Basin, at both federal and state levels, to determine the possibility and attainability of nutrient reductions. These questions are being asked at several spatial scales, but ultimately are driven toward the largest spatial scale - Gulf of Mexico hypoxia. The Mississippi approach has been to utilize inter-agency collaboration to identify watersheds where BMP nutrient reductions can be demonstrated and to discern the effectiveness of those BMPs. Harris and Porters Bayous are two HUC 10 watersheds where BMPs have been installed on the landscape, and where tiered water quality monitoring with identical sampling frequencies provides a means for quantifying both reductions in nutrient concentrations and loads. Water quality data is being collected at three tiers. The first Tier (edge of field) is being collected by MSU, while Tiers 2 and 3 are being collected by USGS. Nutrient reductions in concentration, 1-year post BMP implementation are discernible at the Tier 1 scale, but are not yet known at Tiers 2 or 3 due to continued data analysis. Monitoring of multiple watersheds provides environmental variables and landscape characteristics that suggest reasons for the observed reductions. These initial answers provide previously unknown information towards improving in state aquatic ecosystem health as well as critically important BMP attainability estimates to inform Gulf of Mexico restoration recommendations.
Integrated Desalination and Wastewater Treatment Systems
Year: Authors: Kokabian B., Blair M.F., Gude V.G.
Water, energy and environment play a vital role in the sustainability of mankind. Environmental degradation associated with water and energy production/supply processes is the immediate concern faced by many parts of the world. Utilizing wastewater and produced waters as resources to provide for potable water and energy needs could serve as a sustainable alternative to mitigate environmental degradation. Towards this goal, microbial desalination cells allow for efficient wastewater treatment combined with electricity generation and desalination of saline waters. The premise for this research is based on the principles that the bio-electrochemical (BES) systems convert wastewaters into treated effluents while producing electricity and ionic species migration within the system facilitates desalination. A microbial desalination cell (MDC) can be constructed by including an additional saline water chamber in a microbial fuel cell using anode and cathode exchange membranes. Domestic wastewater can serve as a substrate provider while air cathodes can provide oxygen to accept electrons. A new concept to provide in-situ oxygen generation in the cathode section by algae to increase electron mobility (i.e. electric current) in microbial desalination cells is presented in this paper. Treated wastewater in the anode chamber will be allowed to pass through the cathode chamber to serve as CO2 and nutrient rich medium for algal biomass growth and in-situ oxygen generation. This process eliminates current issues encountered in microbial desalination cells such as salt accumulation in treated wastewater, pH drop and rise in anode and cathode chambers and provision of strong electron acceptors such as oxygen. This paper presents the results from experimental studies and energy analysis on the feasibility of algal microbial desalination cells.
Monitoring fine suspended sediment in streams using high frequency acoustic signal attenuation measurements
Year: Authors: Kajdan T.A., Carpenter Jr. W.O., Chambers J.P., Goodwiller B.T., Surbeck C.Q.
This research focuses on a new device to measure fine suspended sediment particles in rivers and streams using acoustic signal attenuation measurements. The purpose of this device is to create a high frequency signal attenuation system that will be able to measure concentrations continuously without having to physically visit the site in order to obtain the samples. This system will be non-intrusive as well as relatively cost-effective in comparison with the methods that have previously been adopted. Two 20 MHz transducers will be aligned in a pitch-catch configuration at a distance based upon near field effects and noise level caused by the interaction between the transmitting and receiving transducers. The 20 MHz acoustic device will be able to measure particles ranging from 0.2 to 65 µm in size. A vast attenuation database has been created at the National Center for Physical Acoustics (NCPA), located in Oxford, Mississippi, to account for this range of particle sizes. The database includes acoustic signal attenuation measurements of bentonite, kaolinite, illite, and silt, which were used to broaden the sediment range. The database consists of peak-to-peak voltage data that was captured by the receiving transducer during the experiment and displayed and analyzed using LabView 2010. This voltage data corresponds to known particle concentrations. A digital signal processing (DSP) board will be used to process the data obtained from the 20 MHz transducers in the field. The attenuation signal that is measured in the field will be compared with the database so that a sediment concentration can be determined. The 20 MHz acoustic device will be calibrated at the NCPA using the attenuation database. Once the calibration is complete, the 20 MHz acoustic device will be deployed at Harris Bayou, located in Coahoma County, Mississippi. This particular bayou has relatively steady base flow, which is ideal for the acoustic device. The steady base flow of this bayou ensures that the signal produced by the transmitting transducer will not reflect off of the surface of the water causing inaccurate attenuation data. The digital signal processing board will be mounted in the gauging station housing that is currently being used by the United States Geological Survey (USGS). The results that are obtained from the field will be compared with concentrations that the USGS finds from its grab samples.
Solid phase extraction, QuEChERS cleanup, dansylation with LC-MS/MS detection as an improved method for analyzing five estrogens in wastewater
Year: Authors: Gunatilake S.R., Steelhammer S., Kwon J., Xia K., Armbrust K., Rodriguez J.M., Mlsna T.E.
An improved method for the analysis of estriol (E3), estrone (E1), 17α-estradiol (αE2), 17Β-estradiol (ΒE2), and 17α-ethinylestradiol (EE2) in wastewater is described. The method includes sample preparation using solid-phase extraction followed by a "QuEChERS" (Quick Easy Cheap Effective Rugged Safe) cleanup, and a LC-MS-MS detection. Solid phase extraction was carried out using Oasis HLB cartridges and a dispersive solid phase cleanup pack containing MgSO<sub>4</sub>, PSA and C-18. The resulting extract was then derivatized with dansyl chloride. Separation was achieved on an Agilent Zorbex Extend C-18, Narrow Bore RR, (2.1 x 100mm, 3.5 µm) column and quantification was accomplished in the positive ion mode using multiple reaction monitoring. The cleanup method is quick, efficient, inexpensive, and requires only 200 ml of water. Reliable linearities were obtained for all the calibration curves (r<sub>2</sub> > 0.995). Calculated matrix effects were less than 12% for all the analytes and hence, matrix matched calibration curves were not needed. The recoveries for the estrogens ranged from 81–103% with a high repeatability (n=3, RSD = 9%) and low limits of quantification (0.6–0.9 ng/L). The method was used to analyze effluent and influent wastewaters in three Mississippi wastewater treatment plants but is broadly applicable for the determination of trace estrogens in any municipal wastewater samples.
Mississippi's Dam Safety Program
Year: Authors: Sigsby N., Myers D.
Created in 1978, the Mississippi Dam Safety program began the task of identifying dams that were High Hazard and working to get those dams repaired. In 1994, Dam Safety Regulations were defined to classify the hazard potential of dams, establish minimum design and construction criteria, to require regular inspections and to have an emergency action plan for all high hazard dams. These regulations were again revised in 2005 and are currently used today. <br /><br />Created in 1978, the Mississippi Dam Safety program began the task of identifying dams that were High Hazard and working to get those dams repaired. In 1994, Dam Safety Regulations were defined to classify the hazard potential of dams, establish minimum design and construction criteria, to require regular inspections and to have an emergency action plan for all high hazard dams. These regulations were again revised in 2005 and are currently used today.
Source water protection in Mississippi: Just plugging away
Year: Authors: Crawford J., Payne M.
Most of the 3,000 public water system (PWS) wells operating in Mississippi are screened in deep confined aquifers, often overlain with multiple confining layers. Due to this favorable hydrogeologic setting, incidences of groundwater contamination impacting PWSs have not been widely reported in Mississippi. State source water protection efforts have mainly focused on addressing abandoned wells identified in delineated protection areas that may serve as potential conduits for the introduction of contaminants. Unfortunately, the success of these past efforts has been limited due to the sizeable number of abandoned wells in need of plugging and the lack of available funding to help offset the prohibitive cost associated with meeting state regulations.<br /><br />Most of the 3,000 public water system (PWS) wells operating in Mississippi are screened in deep confined aquifers, often overlain with multiple confining layers. Due to this favorable hydrogeologic setting, incidences of groundwater contamination impacting PWSs have not been widely reported in Mississippi. State source water protection efforts have mainly focused on addressing abandoned wells identified in delineated protection areas that may serve as potential conduits for the introduction of contaminants. Unfortunately, the success of these past efforts has been limited due to the sizeable number of abandoned wells in need of plugging and the lack of available funding to help offset the prohibitive cost associated with meeting state regulations.<br /><br />The well decommissioning program process began with MSDH's selection of a licensed water well contractor to perform the actual plugging. Accompanying this phase was the decision to contract with MsRWA to coordinate the well abandonment procedure and to assist in prioritizing the plugging of over 200 wells identified thus far. Eleven wells considered moderate risks to contamination (as determined by SWAP) and 13 higher ranked wells have been properly decommissioned and fully funded by the program during 2012. Future plans are to maintain the well decommissioning program provided EPA continues to receive funding from Congress for the capitalization grant.
An Assessment of Private Wells Used for Drinking Water in Mississippi
Year: Authors: Barrett J.
The majority of Mississippians enjoy access to one of the 1200 public water systems in Mississippi. Having access to a public water system provides the citizens with safety and quality of water through the regulatory enforcement of the Mississippi State Department of Health-Bureau of Public Water Supply (MSDH). Mississippi citizens on private wells do not have the luxury of knowing the quality and/or quantity of their water on a regular basis. In this presentation, by comparison of United States Census Data and MSDH data, the areas of Mississippi that have the highest concentrations of citizens on private wells will be derived. Data will be gathered to determine the likely contaminants to private wells in each particular county. This information will highlight the areas that could benefit the greatest from avenues in which private well owners can check the quality of their water as well as inform the surrounding water systems of their capacity to expand.
Occurrence and removal of pharmaceuticals and personal care products in different wastewater plants in Mississippi
Year: Authors: Kwon J., Brown A., Rodriguez J.
Residues of pharmaceuticals and personal care products (PPCPs) have been detected in surface waters. It is well known that effluent from wastewater treatment plants (WWTPs) is a major source of contamination of PPCPs in surface waters. The most frequently detected and toxic PPCPs, according to peer-reviewed articles published in the USA, are carbamazepine, sulfamethoxazole, gemfibrozil, and galaxolide. Three wastewater treatment plants (A, B, and C) in Mississippi, with different treatment technologies, were selected. Influent (law water) and effluent (treated water) were sampled from the three WWTPs over the course of one year. Upstream and downstream samples of the WWTPs were also collected. All the four PPCPs were detected in all influents, with galaxolide and sulfamethoxazole showing the highest concentrations of 4,020 ng/L and 3,905 ng/L, respectively while carbamazepine was detected at the lowest levels (66-348 ng/L). All the PPCPs were detected in all effluents except sulfamethoxazole. Different PPCPs were removed to different extent in the WWTPs, varying from -99% to 100%. Carbamazepine showed the lowest removal (-99% to 30%) and gemfibrozil showed the highest (73% to 100%) in the WWTPs. WWTP A gave lower removal rates than WWTPs B and C for sulfamethoxazole. WWTP A showed higher removal rates than WWTPs B and C for galaxolide. Comparing the concentrations of upstream PPCPs to the downstream, there is an apparent increase in concentrations.
Urban Flow-Through Facilities' Soil Media Compositions for Stormwater Quality and Quantity Improvements
Year: Authors: Overbey E., Gallo E., Kröger R.
An emerging practice for reducing the amount of nutrients and pollutants entering receiving waters is to filter urban stormwater runoff with infiltration based best management practices (BMPs). Small-scale BMPs for urban environments such as rain gardens, bioretention facilities, flow-through planters, and green roofs have been shown to slow peak flows and reduce the amount of nutrients that are washed from impervious surfaces during storm events. These BMP technologies are relatively new in design practice and all aspects of their structural design, potential for nutrient removal, and peak flow reduction is yet to be fully examined. The objective of this study is to provide understanding of different soil compositions in flow-through planters currently used in practice and determine their potential for water quality and quantity improvements. Eighteen 30"x18"x12" aquaria were modified to model flow-through facilities in a practical application using synthetic runoff which contained a 2ppm mixture of nitrogen and phosphorus. Soil mixtures varied across treatments and were composed of different percentages of sand, topsoil and compost. A hydrograph was used to simulate the most intense 4.5 hours of a 2-inch, Type II 24-hour rainfall event and was applied to the aquaria using manually controlled flow rate pumps. The outflow hydrograph was recorded to determine if peak flow was reduced and water quality samples were collected and analyzed to determine if nitrate and phosphate retention differed between soil treatments. Water quality data analyses indicate phosphate retention values ranged from (33-81%) and poor retention of nitrate (4- 23%). Nitrate values showed increases in concentration for some treatments. Preliminary results indicate the need for modification of the study design as higher infiltration rates in soil treatments reduced the residence time expected for the stormwater runoff in these facilities and as a result did not allow for the desired reduced peak flow. Further research is needed to test structural design modifications of flow-through facilities in order to increase their quantity reduction performance.
Introduction to Changing Site Design Standards for Stormwater Management
Year: Authors: Bathi J.R., Rhoads S.
A recent regulatory trend is to base storm water control requirements on the total volume of storm water runoff from a site rather than on runoff rates or a specific pollutant removal rate. This trend is based on a growing body of research which has concluded that volume-based controls accomplish the concurrent benefits of pollutant reduction, peak flow reduction, and base flow protection. The focus on runoff volume as the common currency for best management practices evaluation is gaining wider acceptance across the country. Current regulations in the region demand a high level of stormwater infrastructure to meet the total volume of detention storage required. Instead, the evolving volume based controls have been proving to be less cost intensive with distributed green technologies at the source level. The purpose of this paper is to provide an overview of new volume based standards and rainfall frequency analysis procedures for selecting the appropriate control matrix for an area. In addition, we have summarized commonly used green infrastructure practices, and outlined available computer models for designing and evaluating site level green infrastructure techniques.
Implementing Green Infrastructure through new Policies and Tools
Year: Authors: Gallo W.C., Overbey E.
The underlying theory behind green infrastructure or sustainable stormwater design is that the cumulative impact of many small facilities is greater than that of a few large facilities. This concept depends on the design, installation and management of many more facilities than a traditional pipe and detain ordinance would have created. Instead, a collection of small-scale, vegetated, best management practices are designed to fit seamlessly into the urban fabric to manage smaller storm events close to the source, mitigate nearly every new impervious area, and promote as much infiltration or bio-retention as possible.<br /><br /> For a municipality to move toward a green infrastructure approach requires major changes to how their stormwater ordinance is organized and administered. More facilities, potentially means more submittals, more calculations to check, and more designs to approve. A few municipalities have been grappling with this paradigm shift for the last decade. Their experience indicates that the shift toward green infrastructure requires new tools, which simplify the administrative and design process, and new policies, which ensure the goals of green infrastructure are implemented effectively. <br /><br /> This presentation will explore a few of the specific policies and tools, which have been developed to implement green infrastructure including: <ul style="padding-left:25px;"><li style="list-style:circle;"> a pre-development definition which ensures policies will improve watershed protection over time; </li> <li style="list-style:circle;"> a low application trigger which is central to the concept of managing stormwater at the source;</li> <li style="list-style:circle;"> a detention requirement, which when combined with a low application trigger, does not impede urban development and also provides a high level of overall flood protection;</li> <li style="list-style:circle;"> an almost wholesale embrace of small-scale vegetated best management practices (BMPs), which focus on infiltration; and</li> <li style="list-style:circle;"> a collection of tools specifically designed to facilitate the design, approval, and implementation of small-scale BMPs.</li></ul>
Teaching How Water Works: Informal Science Education through Exhibit Design
Year: Authors: Brzuszek R.
The mission of the Crosby Arboretum, Mississippi State University Extension (located in Picayune, Miss.), is to preserve, protect and display plants and their communities native to the Pearl River Drainage Basin. The Crosby Arboretum's nationally award-winning master plan has designated a portion of its facility for the creation of a small stream swamp forest educational exhibit. Small stream swamp forests are wetlands situated on bottomlands of small streams that are predominated in species type and frequency by black gum (Nyssa biflora) and sweet bay magnolia (Magnolia virginiana). As specified in Mississippi's Comprehensive Wildlife Conservation Strategy by the Mississippi Department of Wildlife and Fisheries (MDWF), small stream swamp forests are considered vulnerable in the state of Mississippi. The proposed swamp forest exhibit will address MDWF priorities through the construction and management of the habitat type, as well as providing a venue for public education and experience in this vulnerable forest.<br /><br /> The Crosby Arboretum Foundation was awarded a grant to create a small stream forest educational exhibit. Graduate students in the Department of Landscape Architecture at Mississippi State University utilized a semester-long class project in spring 2011 to research and design the proposed exhibit. Students conducted a literature search on small streams and related wetlands and visited several in situ small stream swamps in Mississippi. Students recorded environmental data at the natural wetlands to inform the restoration design. Students also conducted an environmental inventory and analysis at the proposed exhibit site that recorded the site's hydrology patterns, plant species, soils and other data. A design charrette, or a collaborative session to determine solution to the design problem, was conducted with wetland specialists and landscape architects to develop the preliminary design. This paper will discuss the method used to develop the exhibit design and will exhibit the drawings for the proposed stream and associated wetland types. Long-term vegetation monitoring will be initiated after construction.
Influence of Spatial Precipitation Patterns on Seasonal Recharge in the lower Mississippi River Alluvial Aquifer
Year: Authors: Dyer J., Mercer A.
Water resources in the lower Mississippi River alluvial valley play a critical role in agricultural productivity due to the widespread use of irrigation during the growing season. Although the region receives abundant precipitation throughout the year, the unknown specifics of meteorological modifications in the region, along with continually changing anthropogenic needs on the groundwater system, makes it difficult for water resource managers to make sound decisions for future water sustainability. Additionally, agriculture in this region is under considerable strain due to diminishing groundwater availability and the non-sustainable trend in irrigation draws from the alluvial aquifer. As a result, it is crucial to correlate local rainfall patterns with aquifer water levels to better determine the spatial and temporal influence of precipitation on regional groundwater levels. This project will address water availability in the lower Mississippi River alluvial aquifer (LMRAA) over northwest Mississippi through an assessment of historical precipitation variability using high-resolution radar-derived precipitation estimates. This information will be used to estimate current and future precipitation availability over the region, which will be compared with regional groundwater observations to determine the level of interaction between rainfall and sub-surface water levels. Results of this project will aid in determining the natural limits to water resource availability, as well as the relationship between regional precipitation and groundwater variability.
Surficial Geology and Soils in the Mississippi Delta: In Search of Infiltration Data
Year: Authors: Mason P., Thompson D.
The water-bearing sands and gravels of the Mississippi River Valley alluvial aquifer (MRVA) underlying Mississippi's Delta region are very prolific and are important to agricultural interests. Significantly, the aquifer's overlying capping layer, or topstratum, is important in understanding the sustainability of this resource. This relatively thin topstratum is a primary controlling factor in determining how much direct recharge from precipitation passes from the surface to the aquifer. This process ultimately plays an important role in recharging this increasingly stressed and heavily utilized aquifer. Concepts and historical research vary regarding the permeability and character of the topstratum. Fisk (1944) described the topstratum as "various combinations of sand, silts, and clays" comprising a "relatively impervious topstratum". Little is known about specific locations in the Delta where direct recharge through the topstratum might be enhanced, restricted, or absent. As a result, previous efforts to simulate the groundwater flow system have postulated various schemes for assigning infiltration. These have included: 1) one uniform infiltration rate, 2) low rates in most areas with moderately low rates in zones controlled by topstratum geology, and 3) moderate to high rates in well-drained soils zones with no infiltration elsewhere. In an effort to clarify and illuminate the level of knowledge regarding this capping interval, systematic research and review of existing literature, surface geological mapping, soils mapping, and pertinent data sets is being undertaken. Some of the available data may be reprocessed or enhanced in order to better identify the various soil parameters, geomorphologic features, and depositional units which are thought to be useful tools in predicting and developing infiltration rates for the MRVA.
Low flow, how low should we go?
Year: Authors: Johnson D.R.
The determination of the minimum flow needed to support aquatic life and meet the needs of the Clean Water Act is a complex issue that has generally been answered with quick and meaningless statistical flows. This paper will examine a number of different methods used to establish low flow, and will compare them to observed flows several rivers in the Mississippi Delta.<br /><a href="/pdf/2013_johnson_pres.pdf">Download the presentation</a>
Assessing the Impacts of Future Climate Change on Peak Flows in a Forested Watershed
Year: Authors: Dakhlalla A.O., Parajuli P.B.
Future climate changes, such as precipitation, temperature, and carbon dioxide (CO2) can have dramatic impacts on the hydrological cycle. These climatic changes can also increase the intensity and occurrence of peak flow events, which cause significant damage to agriculture and infrastructure. This study was conducted in the Lower Pearl River Watershed (LPRW) in southern Mississippi, which is dominated by forests and is characterized by its high peak flows. The Soil and Water Assessment Tool (SWAT) was utilized to assess the impact of future climate change scenarios on peak flow frequency and magnitude. <br / ><br /> The SWAT model was calibrated and validated for streamflow at five United States Geological Survey (USGS) gage stations (Bogalusa, Columbia, Monticello, Hanging Moss Creek, and Jackson) with good model performance based on the coefficient of determination, Nash-Sutcliffe Efficiency index, and root mean square error statistics. Future climate change scenarios were based on adjusting precipitation, temperature, and CO2 values. Observed daily precipitation and temperature data for the years 1981 to 2010 were used as inputs in a stochastic weather generator model to generate future climate data with the same statistical characteristics as the observed data. The occurrences and magnitudes of extreme peak flow events in the LPRW were analyzed under each climate scenario by developing flood hydrographs. Employing climate scenarios will aid in determining which climatic parameters have the most and least influence on peak flow magnitude and frequency. This study is expected to help in implementing best management practices (BMPs) more effectively in the LPRW that serve to attenuate peak flows.
Development of the Mississippi Irrigation Scheduling Tool-MIST
Year: Authors: Sassenrath G.F., Schmidt A.M., Schneider J., Tagert M.L., van Riessen H., Corbitt J.Q., Rice B., Thornton R.
Increasingly variable and uncertain rainfall patterns together with higher production input costs have led farmers to rely on supplemental irrigation to enhance production. While many irrigation methods have been developed for dry climates, few tools are available for humid, high rainfall areas. Moreover, most scheduling tools require extensive data collection, entry and simulation runs, limiting their practical utility during the production season. We have designed the Mississippi Irrigation Scheduling Tool (MIST) as a web-based, easy to use management tool for crop producers. An estimate of crop water use is made using the modified Penman Monteith to calculate daily evapotranspiration. The "checkbook" water balance method sums the water balance of the soil, plus water from rainfall or irrigation, minus water used by the crop or evaporated from the soil. This method indicates the need for irrigation when the soil water available to the plant falls below that which is readily available for crop growth. To enhance utility, the MIST has been implemented in a web interface, allowing producers to access the information from anywhere through tablet computers or smart phones. To reduce the data entry requirements, the system relies on national databases for automated integration with a water balance model. The system was tested at multiple production sites during the 2011, and 2012 growing seasons. This presentation will give details on the development of input parameters for the water balance calculation, including crop water use and soil moisture, and water balance during the growing season for corn and soybeans. Additional presentations in this session will describe the implementation of the user interface (Rice et al.), calibration and validation of the model (Prabhu et al.), and spatial accuracy of national databases (Thornton et al.). The MIST will provide producers, consultants and other professional colleagues with a reliable, accurate, and easy to use tool for improved water management.
Implementation of the Mississippi Irrigation Scheduling Tool in a dynamic web-based format
Year: Authors: Rice B., Sassenrath G.F., van Riessen H., Schmidt A.M., Tagert M.L.
The Mississippi Irrigation Scheduling Tool (MIST) has been developed to provide a daily calculation of water balance for row crop production. This daily calculation incorporates field specific data on soil type, tillage depth, row spacing, and crop type to make a recommendation on crop water needs. Weather data is automatically downloaded from national and regional databases and used to calculate daily evapotranspiration rate using the Modified Penman-Monteith equations. The first goal of MIST was to make it more accessible to the users. To do this, MIST was implemented as a web application, developed with Java and HTML. Using a web application eliminates the need for the user to download, install and update software. The main difficulty with a web application is making sure that every browser is displaying the web pages correctly since each web browser can interpret code differently. Incompatibilities between web browsers were observed a few times; one of these occurrences was with the font that was being used. Potential incompatibilities are determined by testing the system on multiple web browsers and platforms, though updates in these systems may present problems in the future. All the data is stored within a MySQL database, which currently contains twenty tables each having between three to twenty data columns depending on the data stored. Database security is maintained by restricting server connections to local only. One of the more common SQL attacks is done through SQL injection. Prepared statements are used to prevent these types of attacks. Most of the data are stored in plain English text with a table's data column. Passwords are converted to a MD5 checksum. MD5 checksum is a cryptography based algorithm that allows the storage of data without knowing what the data actually is. This provides security in the event someone is able to obtain access to the database—sensitive information will not be accessible. There are a few different types of user ranks within the interface: admin, manager, consultant, company, and farmer, with each user rank assigned different permissions. To assist in the tedious task of setting up each field within the farm, farmers are allowed to select the border of their field with Google maps. Implementing MIST has been full of challenges and decisions that will be discussed in this paper. Given the widespread adoption of tablets and smartphones, a web application provides equal access to any device that has access to a web browser.
Uncertainty, calibration and validation of the Mississippi Irrigation Scheduling Tool model
Year: Authors: Prabhu R., Lee N., Wadsworth M.C., Sassenrath G.F., Schmidt A.M., Crumpton J., Rice B., van Riessen H.
Implementation and use of a model requires an estimate of its accuracy. The Mississippi Irrigation Scheduling Tool (MIST) is an on-farm decision support tool to assist farmers in irrigating. The accuracy of the model is critical in designing good water management protocols. This research presents the results of the uncertainty analysis of the MIST model, showing the margin of error (uncertainty) of the irrigation advice. The basis for the verification and validation of the model is also given. The MIST calculates the daily soil water balance in a crop field from daily weather measurements, irrigation, and rainfall, accounting for crop type, planting date, soil type, tillage, and other field-specific information. The model output informs farmers of when irrigation is needed. The uncertainty analysis determines the margin of error in the irrigation decision and gives a range within which irrigation is feasible. The current uncertainty analysis also gives essential information on the influence of input parameters on the final irrigation recommendation calculated by the water balance. <br /><br /> The uncertainty calculations were based on Taylor's Series Method for the calculation of the total systematic uncertainty arising from measurement error of variables in the water balance calculation. The errors in measurement were one standard deviation in range, equivalent to an uncertainty with a confidence level of 68.2%. Because the current day's soil water balance depends on the previous day's water balance, the computations are iterative. As equations cascade to calculate the daily water balance, the uncertainties also propagate through the equations. Initially, uncertainty quantifications were performed for two sets of water balance calculations using local weather data. The final uncertainties for the water balance were of the order 3-6%, which is within the acceptable range for error.<br /><br /> The MIST water balance calculations were validated using local weather data consisting of rain days, and significant changes in the solar radiation, relative humidity and wind speed. The final water balance results showed values within acceptable ranges and comparable to in situ measurements of soil moisture. The final relative uncertainty in the water balance value was around 9%, which is in the normal range of margin of error. The current MIST web-based application and uncertainty quantification have been verified and validated for current parameters. The accuracy of the model was shown to be suitable for use by farmers in the Mississippi Delta area, and will help improve water management in crop production systems.
Nutrient and Suspended Sediment Mitigation Through the Use of a Vegetated Ditch System Fitted with Consecutive Low-grade Weirs
Year: Authors: Flora C., Kröger R.
Mississippi is the largest producer of channel catfish (Ictalurus punctatus) in the United States. Channel catfish ponds cover over 20,000 hectares of land, mainly concentrated in the Alluvial Valley of northwest Mississippi. Water management practices to reduce mass discharge from ponds are currently a major point of concern, especially in light of potential regulations through nutrient criteria development. A vegetated ditch fitted with consecutive low-grade weirs is anticipated to be a practical and effective option of reducing nutrients and suspended solids entering downstream receiving systems. This study assesses the effect of low-grade weirs on chemical retention and settling of aquaculture pond effluent in a single drainage ditch. Nine embankment ponds were discharged at 48 hour intervals into a single vegetated drainage ditch fitted with 3 low-grade weirs. Two additional embankment ponds were discharged into the ditch while boards were removed from weirs, thus acting as a conventional ditch. Data were analyzed to quantify the ability of the low-grade weir system to reduce the levels of ammonia, nitrate, nitrite, total inorganic phosphorus, particulate phosphorus, and dissolved inorganic phosphorus. The levels of total suspended solids and volatile suspended solids will be compared across the system. As water passes each weir the nutrient and suspended solid loads should decrease through the system, overall reducing the load entering the downstream receiving systems.
Potential environmental risk of the phosphorus status in soils receiving poultry manure applications in Mississippi
Year: Authors: Ramirez-Avila J.J., Oldham J.L., Kingery W.L., Crouse K.K., Ortega-Achury S.L.
Phosphorus (P) enrichment of surface and ground water involves a combination of source factors such as high soil test phosphorus (STP) levels and site-specific soil and field characteristics that influence P transport by water flow overland and through the soils. Long-term applications of manure have generally increased STP levels to a greater degree than has fertilizer application because manure applied to meet the nitrogen (N) needs of crops provides more P than utilized by crops. Preliminary research found that subwatersheds within the poultry production counties in Mississippi have a high potential for soil and water degradation from manure P and N. An assessment was developed to increase understanding of STP levels in soils of the top 20 poultry production counties in Mississippi. The study performed a descriptive summary and analysis of temporal dynamics of STP in 15,057 soil samples, submitted for forage and pasture crop recommendations, after analysis by the Mississippi State University Extension Service Soil Testing Laboratory for 10 annual periods from 2002-2003 to 2011-2012. There were gradual annual changes in STP level ranges from the first (5 to 3780 lb ac<sup>-1</sup>) to the last year (5 to 3980 lb ac<sup>-1</sup>). Individual peak STP values of 5990 and 4840 lb ac<sup>-1</sup> were observed in the 2nd and 7th year, respectively. However, mean STP levels increased from 113 lb ac<sup>-1</sup> to 302 lb ac<sup>-1</sup> from the first to the last year with the highest mean STP level of 356 lb ac<sup>-1</sup> in the 7th year. The MSU Extension Service would not recommend additional external P for 69% of the soils sampled in the last year of the dataset; in the first year this value was 38%. These results indicate increased STP in these soils that could contribute P to runoff and leaching flows. Because of the susceptibility of these areas to manure source P leaching and runoff, Best Management Practices should be implemented that manage P source and off-field transport to minimize environmental impacts. Balancing P inputs with crop removal is an essential part of a sustainable practice to controlling P losses. Maintaining moderate STP levels or reducing high STP levels can reduce the potential for transport of P from both particulate and dissolved P. Comprehensive nutrient management plans should be developed and implemented for all poultry production operations for the optimal use of poultry manure.
Numerical Modeling of Sediment-Associated Water Quality Processes in Natural Lakes
Year: Authors: Chao X., Jia Y., Shields Jr. F.D.
Sediment is a major nonpoint source pollutant. It may be transported into surface water bodies from agricultural lands and watersheds through runoff. These sediments could be associated with nutrients, pesticides, and other pollutants, and greatly affect the surface water qualities. Therefore, sediment has been listed as the most common pollutant in rivers, streams, lakes, and reservoirs by the US Environmental Protection Agency (USEPA). <br /><br /> This paper presents the development and application of a three-dimensional water quality model for predicting the distributions of nutrients, phytoplankton, dissolved oxygen, etc., in natural lakes. Three major sediment-associated water quality processes were simulated, including the effect of sediment on the light intensity for the growth of phytoplankton, the adsorption-desorption of nutrients by sediment and the release of nutrients from bed sediment layer. This model was first verified using analytical solutions for the transport of non-conservative substances in open channel flow, and then calibrated and validated by the field measurements conducted in a natural oxbow lake in Mississippi. The simulated concentrations of water quality constituents were generally in good agreement with field observations. This study shows that there are strong interactions between sediment and water quality constituents.
Effects of a native rough fish on water quality
Year: Authors: Goetz D., Kröger R., Miranda L.E.
The smallmouth buffalo (SMB) (<em>Ictiobus bubalus</em>), a large bodied benthivore commonly considered a rough fish, is native to Mississippi. Smallmouth buffalos frequently access floodplain lakes during periods of high water level, and remain isolated within them for extended periods of time after the water recedes. Based on evidence from other benthivore studies we hypothesized that high densities of SMB may contribute to poor water quality conditions. We tested this hypothesis in 0.05 hectare, shallow (<1.5 m) earthen ponds at three stocking densities. Nine ponds were randomly stocked with either a low (15 kg/ha), moderate 85 (kg/ha), and high (315 kg/ha) density and measured for water quality parameters over a ten-week period during the summer of 2012. Results from repeated measures ANOVA suggest SMB at high and moderate densities significantly (p < 0.05) increased chlorophyll, turbidity, total suspended solids, volatile suspended solids, temperature, total inorganic phosphorus, while decreasing dissolved oxygen, and Secchi depth, both through time and across treatments. Several previous studies also attribute high benthivorous fish density to enhanced productivity through feedback mechanisms that keep nutrients and sediments in constant suspension. However, most studies have looked at densities much greater than 315 kg/ha (500 +kg/ha). Our results suggest that effects of SMB even at moderate densities may contribute to degraded water quality conditions in natural habitats such as shallow floodplain lakes.
Spatial distribution of Sediment and Nutrient Loadings from Upper Pearl River Watershed (UPRW)
Year: Authors: Jayakody P., Parajuli P.B., Cathcart T.P.
Deterioration of surface water quality is one of the most concern issues in the U.S. The knowledge of spatial and temporal variability of water quality parameters may help to formulate mitigation plans to improve water quality. This study was designed to investigate temporal and spatial variability of sediment, total nitrogen (TN), and total phosphate (TP) loadings to the surface water through a modeling approach. The Soil and Water Assessment Tool (SWAT) was applied for Upper Pearl River Watershed (UPRW) in central Mississippi. Water samples were collected from Burnside and Lena USGS gauging stations. The SWAT model was calibrated and validated for daily time steps using manual and automatic (SUFI-2) methods from Feb 2010 to May 2011. Preliminary results showed good to very good model performances with the coefficient of determination (R2) and Nash-Sutcliff Efficiency Index (NSE) from 0.6 to 0.8 (flow), 0.3 to 0.6 (sediment), 0.6 to 0.7 (TN), and 0.5 to 0.6 (TP) during both hydrologic and water quality model calibration and validation. Sub-watersheds were ranked based on water quality pollutants loading to prioritize land areas for watershed management operations.
Monitoring and Modeling of Fecal Coliform Bacteria Loads in the Upper Pearl River Watershed
Year: Authors: Parajuli P.B., Jayakody P., Brooks J.P.
Pathogens loading from the non-point sources of agricultural and non-agricultural activities contribute to water quality degradation. Developing Total Maximum Daily Loads (TMDLs) for the pathogens (e.g. fecal coliform bacteria, E. coli) require quantifying bacterial load contribution from potential sources. Quantifying bacterial loads from each source will help in developing pathogenic load reduction strategies to meet applicable water quality standards.<br /><br /> The objective of this research was to monitor fecal coliform bacteria concentrations and quantify bacteria loads from the Upper Pearl River Watershed (UPRW-7,885 km<sup>2</sup>) in the east-central Mississippi. Analysis of observed fecal coliform bacteria concentrations with stream flows from the watershed will be presented. Preliminary results from the model simulations with seasonal variability of bacteria concentrations will also be presented using appropriate statistics.
A shallow-water equation based one-dimensional dynamic wave model with non-hydrostatic pressure
Year: Authors: Wei Z., Jia Y.
Coastal wave is one of major forces that dominate coastal hydronydamics, sediment transport, morphology and threaten coastal infrastructures. In recent years, the non-hydrostatic technique for solving Reynolds-averaged Navier-Stokes equations has been developed for wave propagation study. It has been shown that this method has a comparable accuracy for wave simulation to Boussinesq-type approaches and a better computing efficiency. <br /><br /> In this paper, a one-dimensional depth-integrated non-hydrostatic pressure wave model for wave propagation, breaking and run-up is developed based on the numerical method proposed by Stelling and Duinmeijer. In this numerical method, the non-conservative form of Navier-Stokes equation is solved for either momentum conservation or energy head conservation by applying different advection approximation methods. The method is, therefore, able to handle rapidly varied water flows (such as wave breaking) in wide range of Froude numbers. When wave run-up is concerned, wetting and drying treatment plays a key role for many numerical models. The wet & dry handling approach in the method is simple, efficient and capable of reserving positive water depth.<br /><br /> In this non-hydrostatic wave model development, the fractional time step method is adopted. The shallow water equations without non-hydrostatic pressure terms are solved for approximation of velocity; a tri-diagonal equation for non-hydrostatic pressure terms is then solved, and the approximate velocity is corrected by non-hydrostatic pressure terms. The free surface elevation is calculated by the depth-averaged continuity equation to satisfy global mass conservation. This model will be validated by an analytical solution and several benchmark wave dynamics test cases; it is anticipated the model can predict wave breaking and run-up processes effectively.
Modeling Sediment and Phosphorus Yields Using the HSPF Model in the Deep Hollow Watershed, Mississippi
Year: Authors: Diaz-Ramirez J., Martin J., McAnally W., Rebich R.A.
The impact of excess nutrient loads on eutrophication of waterbodies, including the increasingly frequent occurrences of harmful algal blooms and hypoxia, is well known and well documented. The Mississippi River/Gulf of Mexico Hypoxia is also a major environmental issue, and a key component of the Gulf Hypoxia Action Plan is the development and implementation of state nutrient reduction strategies. Effective implementation of nutrient load reductions requires that analytical tools be available to accurately estimate loads from watersheds and waterbodies as a function of hydrologic conditions. Hydrologic models have widely been used to accurately estimate outflows from watersheds, and to a lesser degree sediment and nutrient loads. Factors impacting runoff of nutrients are not well understood and as a consequence predictions of nutrient loads are highly uncertain. This research evaluated the ability of the Hydrological Simulation Program—FORTRAN (HSPF) to simulate storm, seasonal, and long-term runoff, sediment, and phosphorus transport at the farm scale in the Deep Hollow drainage area, Mississippi. The main goal was to demonstrate the usefulness of HSPF as a computer tool for future environmental management and planning in the Mississippi Delta region. When analyzing the datasets developed by U.S. Geological Survey, 69 events were selected to setup and evaluate the HSPF model. Model evaluation consisted in splitting the available data in two different time periods, calibration from 1997 to 1998 and validation in 1999. Runoff processes were evaluated using 45 events for calibration and 24 events for validation. In evaluating sediment export processes, 29 and 11 storm events were utilized in calibration and validation periods, respectively. Phosphorus simulations (dissolved and total) were evaluated using 19 and four storm events in calibration and validation periods, respectively. The HSPF model was setup to evaluate runoff, soil erosion, dissolved & total phosphorus to storm, monthly, and annual time scales. <br /><br /> This study concluded that the HSPF runoff model's simulations of storm-by-storm, long term monthly, and annual intervals were very good. In simulating suspended sediment loads, HSPF performance was poor for storm-by-storm analysis. However, long term monthly, and annual suspended sediment load simulations were tracked fair and good, respectively. Simulations of dissolved phosphorus of storm-by-storm and long term monthly intervals were good. Simulated annual dissolved phosphorus loads correlated very good with observed data. Similarly, HSPF performed good in simulating long term monthly total phosphorus loads and showed very good results in modeling annual total phosphorus loads exported from Deep Hollow drainage area.<br /><a href="/pdf/2013_diaz_pres.pdf">Download the presentation</a>
Can National Weather Service Spatially Gridded Radar Precipitation Estimates be Used to Overcome Spatial Variability in Mississippi Precipitation Meas
Year: Authors: Thornton R.F., Sassenrath G.F., Schneider J.M., Corbitt J.Q., Schmidt A.M., Crumpton J., Rice B., van Riessen H.
The goal of this research is to determine how reliable National Weather Service (NWS) spatially gridded radar precipitation estimates are in Mississippi. If results are good, the plan is to incorporate this source of rainfall information into the Mississippi Irrigation Scheduling Tool (MIST). Several rain gauge sources are included in the analysis in order to increase the spatial resolution of precipitation across the state of Mississippi. These sources include The Community Collaborative Rain, Snow and Hail Network (CoCoRahs), National Weather Service Cooperative Observers (COOP) and one DREC station. These rain gauge values were obtained for July 1-31 2012. Each rain gauge location is referenced by latitude and longitude, so it can be compared to NWS radar precipitation estimates at the same coordinates.<br /><br /> Summertime precipitation in Mississippi demonstrates a high degree of spatial variability through pop-up afternoon showers and thunderstorms. This research will determine the usefulness of radar-estimated precipitation, the spatial context of which could eliminate the variability problem inherit in point-source measurements. Actual rain gauge values are compared to radar-estimated values through the use of ARCGIS. If it is determined that radar-estimated precipitation is comparable to actual rain gauge data, then this will be incorporated into a tool to aid the Mississippi agricultural community in knowing when to most efficiently irrigate. The analysis will also attempt to find any spatial bias present between the two measurements, resulting in the discovery of any consistent correction coefficients. This, along with other conservation efforts already in place, will potentially help Mississippi farmers to conserve groundwater by supporting recharge of the Mississippi River Shallow Alluvial Aquifer over time.
Effects of vegetation and hydrology on Eh in vegetated agricultural drainage ditches with weirs
Year: Authors: Shoemaker C., Kröger R., Pierce S.
Oxidation-reduction potential (Eh) is an important parameter in predicting biogeochemical reactions occurring in waterlogged soils, including nutrient reduction. Specifically, soil Eh can be used to classify the potential of a system for nitrate reduction, providing a convenient and inexpensive tool for assessing the capacity of primary water bodies for denitrification potential. Continuous automated data loggers were developed, tested, and confirmed for accuracy and precision of Eh measurements. These units were then used to test a vegetated agricultural ditch with weirs in order to assess the influence of hydrology and vegetation on Eh. Six two week testing periods were conducted around two weirs from May-September 2012, with plots above each weir undergoing controlled drainage while plots below each weir functioned as controls subjected to conventional drainage. No differences were observed in the median Eh between vegetated and non-vegetated plots or the median Eh of the location of plot about the weir; however hydrologic changes influenced the range of Eh values regardless of vegetation status. The high levels of temporal and spatial Eh variation inherent in soils make it difficult to determine bulk soil Eh shifts over space and time. A one dimensional moving split window analysis was run to elucidate Eh boundaries by reduction potential. Results of this analysis showed marked shifts of Eh on specific probes, but no overall trends. The standard deviation of probes shifted over time, suggesting the use of controlled drainage coupled with vegetation could increase electrochemical heterogeneity in waterlogged soils. This increase in soil electrochemical heterogeneity may indicate increased denitrification potential as a result of controlled drainage in vegetated ditches.
Spring Microhabitat Oxygen Dynamics of Blue Lake, a Yazoo River Oxbow in Berclair MS
Year: Authors: Andrews C., Kröger R., Miranda L.E.
Shallow oxbow lakes carved in rich alluvial floodplains can support multiple microhabitats that maintain aquatic diversity. Oxbow lakes have a high shoreline to surface area ratio and are often connected to or surrounded by inundated wetlands such as cypress and tupelo brakes, creating within-lake structural habitat variability that may influence biotic composition. Furthermore, these microhabitats fundamentally function in different ways. We studied microhabitat oxygen dynamics of an oxbow lake in the Mississippi Alluvial Valley. Blue Lake has over 8 km of shoreline and is permanently connected to a tupelo brake (approximately 350 ha) inundated with 0.5-1 m of water during the spring, an important time for reproduction. Using hourly diel surface dissolved oxygen (DO) data collected in April-July 2012, we investigate several descriptors of DO dynamics including mean DO, daily DO peaks, rate of DO fall, time of DO peaks, and percent of time above minimum DO thresholds (2 and 5 mg/L). We test differences in spring oxygen dynamics between three habitat types (littoral, pelagic, and brake) using a MANCOVA (p<0.001) and explore the possibility of oxygen refugia in hypoxic systems. Mean temperature along with four DO metrics: mean, minimum, maximum, and range DO showed significant (p<0.05) difference in means and slope between sites. The observed differences promote habitat diversity likely to influence biotic composition and distribution.
Nutrient Reduction Benefits of On-Farm Water Storage Systems in Porter Bayou Watershed
Year: Authors: Tagert M.L., Paz J., Pote J., McCraven K., Kirmeyer R.L.
The Mississippi River Basin contains over 60% of the harvested cropland in the United States, and the Mississippi and Atchafalaya Rivers contribute more than three-fourths of the total nutrient load to the Gulf. Since the 1970's, groundwater levels in the Mississippi Alluvial Aquifer have decreased at a rate of approximately 100,000 acre-feet per year due to increased irrigated acres. Today, there are roughly 18,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer, with an average addition of approximately 35,000 new irrigated acres per year for the past few years. Adequate supply of good quality water is important to sustaining agriculture, the primary industry in the economically depressed Mississippi Delta. Due to concerns over groundwater declines and increasing fuel costs to run irrigation pumps, farmers have begun implementing irrigation conservation measures, such as creating on farm storage areas to capture irrigation and surface water runoff from the field for later use. These systems offer farmers the dual benefit of providing water for irrigation and also capturing nutrient rich tailwater for on farm reuse. This project includes monitoring of two on farm water storage areas in the Porter Bayou Watershed, Mississippi and has two primary research objectives: a) determine the downstream nitrogen and phosphorous concentrations of effluent from water storage systems and b) quantify the effects of water storage systems on downstream flow levels through a watershed. Data collection began in February 2012, with water samples collected for analysis every three weeks throughout the growing season from March-October. Effluent nitrate and phosphorus levels were significantly lower than the inlet levels at both on farm storage systems.
Development and Application of Numerical Models to Environmental Hydraulics
Year: Authors: Chao X., Zhu T., Jia Y., Altinakar M.
Frequent natural and human activity induced disasters are influencing and degrading our water resources. To prevent and mitigate the damages that these disasters bring to our society in terms of water resources and eco-environmental quality, social and human welfare, life and property losses, and economic development, more effective and robust water resource management plans are necessary. The efforts of developing better research design and management tools have led to rapid advances in numerical modeling and computational simulation methodologies in parallel to the rapidly advancing computer technology. Computational models are effective and efficient tools that can be applied to study surface water flows, contaminant transport and environment impacts. Numerical models, CCHE2D and CCHE3D, developed at the National Center for Computational Hydroscience and Engineering of the University of Mississippi, have been applied to simulate the flow, sediment transport, pollutant distribution and water quality in natural water bodies. This paper briefly describes the CCHE2D & 3D models and demonstrate their capabilities by presenting the results of several study cases, including an oxbow lake in Mississippi, where water quality was degraded by excessive agro-chemicals, a hypothetical chemical spill case in a large lake in Mississippi, a salinity intrusion case in Lake Pontchartrain, LA, and hypothetical impact of radioactive chemicals to water quality in Kerr Reservoir and Lake Gaston, VA. The simulation results were validated using field measurements.
Factors affecting low summer dissolved oxygen concentrations in Mississippi Delta bayous
Year: Authors: Lizotte Jr. R.E., Shields Jr. F.D., Locke M.A., Murdock J.N., Knight S.S.
Streams in watersheds supporting intensive row-crop agriculture are vulnerable to ecological degradation due to non-point source discharge of pollutants such as nutrients. Low gradient streams such as bayous are especially susceptible due to increased water residence time, and often result in poor water quality and chronic low dissolved oxygen (DO) concentrations (hypoxia). The goal of the current study was to assess physical, chemical, and biological components affecting low DO during summer of 2011 in three Mississippi Delta bayous. Three sites were selected within each bayou: upstream channel, lake or open water in the water body mid-section, and downstream channel. Dissolved oxygen was monitored at 40 cm depth every 15 minutes for 6-7 days on alternate weeks. Stream surface water samples collected biweekly were analyzed for nutrient and chlorophyll a concentrations. Minimum daily DO levels were frequently below the State instantaneous minimum DO standard of 4 mg/L. Diel DO fluctuation (the difference between daily maximum and minimum DO concentrations) reflected large 24-h DO ranges (=10 mg/L) across all three bayous. Pearson product moment correlations showed minimum DO concentrations to be negatively correlated with total phosphorus (TP) concentrations across all habitats. Total nitrogen (TN) concentrations and dissolved organic carbon (DOC) concentrations were negatively correlated with minimum DO concentrations only in lake habitats. Diel DO fluctuation was positively correlated with water column chlorophyll a concentrations across all habitats. Upstream diel DO fluctuation was also positively correlated with water depth and TP concentrations while downstream diel DO fluctuation was positively correlated with TP but not water depth. Low summer DO concentrations and changes in diel DO fluctuations were affected by both nitrogen and phosphorus driving summer algal blooms (eutrophic to hypereutrophic conditions) in Mississippi Delta bayous. Organic carbon inputs may exacerbate DO minimums in these nutrient-rich systems. As a result, nutrient reduction in all habitats in conjunction with increased water depth in upstream habitats is necessary to improve summer DO concentrations in Mississippi Delta bayous.
Effects of Low-grade weir on hydraulic patterns of agricultural run-off in the Mississippi Delta
Year: Authors: Brison A., Poganski B., Kröger R.
Agricultural best management practices, in the form of low-grade weirs, have demonstrated the ability to mitigate nutrient and sediment loads to downstream aquatic systems. In a recent study, investigations of impacts of artificial low-grade weirs implemented in drainage ditches reported increased hydraulic residence times, an essential component to enhance nutrient reduction. However, research on the success of weirs is currently limited to controlled experiments rather than naturally occurring storm event conditions. This research investigated the effect of low-grade weirs on hydraulic residence time in several agricultural drainage ditches in the Mississippi Delta. Effects of low-grade weirs was assessed by comparing means of storm events and precipitation totals of varying magnitude within drainage ditches between pre- and post- weir implementation. Preliminary results suggest significantly shorter time to peak values between storm events pre- and post-weir implementation (K=11.522; p<0.05; Kruskal-Wallis) and longer time to base (K=18.566; p<0.05). No significant difference was found between pre-and post- weir time to maximum peak height (K=9.334; p>0.05; Kruskal-Wallis). Further research should account for variable physical dimensions, drainage area of each drainage ditch, and the number and spatial arrangement of weirs implemented to understand how weirs impact hydraulic patterns of drainage.
Detection and mapping of cyanobacterial harmful algal blooms using satellite data in one Louisiana lake and four Mississippi lakes
Year: Authors: Dash P.
Cyanobacteria represent the major harmful algal group in fresh to brackish water environments. Cyanobacterial blooms are aesthetically undesirable since they discolor the water, cause turbidity in recreational facilities and synthesize a large number of low molecular weight compounds which cause taste and odor problems. Of particular concern are a diverse range of toxins produced by cyanobacteria, termed cyanotoxins, which are hazardous to human, animal and aquatic ecosystem health. Recently, a procedure was developed to estimate cyanobacterial concentrations by quantifying chlorophyll a (Chl a) and the primary cyanobacterial pigment phycocyanin (PC) using OCM satellite data over a small lake- Lac des Allemands in Louisiana, USA. This required the development of an atmospheric correction and vicarious calibration methodology for satellite data. Empirical inversion algorithms were developed to convert the OCM Rrs at bands centered at 510.6 and 556.4 nm to concentrations of PC. For the algorithms to be uniformly valid over all areas (or all bio-optical regimes) of the lake, a holistic approach was developed to minimize the influence of other optically active constituents. Similarly, empirical algorithms to estimate Chl a concentrations were developed using OCM bands centered at 556.4 and 669 nm. The best PC algorithm (R<sup>2</sup>=0.7450, p<0.0001, n=72) yielded a root mean square error (RMSE) of 36.92 µ g/L (PC from 2.75 to 363.5 µg/L, n=48). The best algorithm for Chl a (R<sup>2</sup>=0.7510, p<0.0001) produced an RMSE of 31.19 µ g/L (Chl a from 9.46 to 212.7 µ g/L, n=48). The results demonstrated the preliminary success of using OCM satellite data to map cyanobacterial blooms in a small lake in Louisiana. In the summer of 2012, five field campaigns were undertaken to four large Mississippi lakes- Lakes Sardis, Enid, Grenada, and the Ross Barnett reservoir in order to obtain a database of photosynthetic pigment concentrations and phytoplankton composition. The objective of this project is to combine multiple satellite data from several sensors such as VIIRS, MODIS AQUA and OCM-2, and developed techniques to quantify cyanobacteria in these four large Mississippi lakes and make the mapped images available through a website for use by water quality managers and general public to rapidly obtain synoptic information on cyanobacterial blooms. Time-series of true color satellite images clearly show the presence of algal blooms. Preliminary analyses of the field data analyzed thus far demonstrate the presence of numerous toxic species of cyanobacteria in these lakes. Preliminary results from this project will be presented.
Factors associated with fate and cycling of nitrogen species in agricultural drainage ditches with implementation of low-grade weirs
Year: Authors: Faust D.R., Kröger R.
The overall objective of this study is to examine factors that may affect the fate and cycling of nitrogen species in agricultural drainage ditches with low-grade weirs installed. Emphasis will be on factors and processes that remove nitrogen from these ecosystems. Particular attention will be paid to factors that have been demonstrated to affect denitrification, as this process results in permanent removal of nitrogen from ecosystems. Three factors that have consistently been implicated in affecting denitrification are nitrate concentration, organic carbon availability, and oxidation-reduction potential. These three factors are the focus under of three specific objective to evaluate effects of these factors on nitrate removal and denitrification potential in sediment pore and overlying water in agricultural drainage ditches. Specific objectives are: 1) Water and sediment samples obtained from ditches at Spruill Farm (Belzoni, MS) will be used in laboratory experiments to determine if organic carbon availability is limiting denitrification potential and whether dissolved or particulate organic carbon is more suitable for denitrification; 2) Results from laboratory experiments will inform conditions used for simulated storm events in experimental v-ditch systems at Mississippi State University's South Farm Aquaculture Facility; 3) Effects of nitrate concentrations, organic carbon availability, and oxidation-reduction potential of sediment pore water and overlying water on nitrogen removal in agricultural drainage ditches at Spruill Farm will then be examined. In addition to best management practices already in use, results from these studies will allow for recommendations to enhance nitrogen removal in agricultural drainage ditch systems.
Evaluating the Variability of Sediment and Nutrient Loading from Crop and Cattle Fields Located in North Mississippi
Year: Authors: Guzman S., Salazar G., Diaz-Ramirez J., Schauwecker T.J.
Excess nutrients are known as a primary problem facing Gulf of Mexico estuaries and coastal waters, leading to nuisance algal blooms, depletion of dissolved oxygen, and other water quality impairments. Soil and nutrient losses encourage siltation and eutrophication in Gulf of Mexico waters. Soil and nutrient exported from agricultural fields into water bodies in Mississippi is a major environmental concern by local, state, and federal agencies. This poster presents runoff and sediment & nutrient loads from two fields in north Mississippi: a 8.4-ha cattle drainage area located on the agricultural research property of the Mississippi Agriculture and Forestry Experiment Station (MAFES), adjacent to Mississippi State University (MSU); and a 11.3-ha crop drainage area located in Leflore County. The cattle field is monitored since 2011 by researchers from MSU Departments of Civil & Environmental Engineering and Landscape Architecture. At the outlet of the cattle field, MSU researchers are using a pressure transducer and automatic sampler to monitoring water depth and water quality, respectively. Field data (discharge and sediments & nutrient concentrations) from the crop drainage area were collected by the U.S Geological Survey from 1996 to 1999. The goal of this research is quantify sediment and nutrient loads by storm events yielded from fields managed with crops (soybeans and cotton) and beef production grazing pasture. Currently, we are computing and analyzing sediment and nutrient loads by storm events and planning to show results at the conference.
Assessing and Modeling Sediment Loads from Stream Corridor Erosion along the Town Creek in Mississippi
Year: Authors: Ramirez-Avila J.J., Langendoen E.J., McAnally W.H., Ortega-Achury S.L., Martin J.L., Bingner R.L.
A research study was developed focused on the identification, assessment, evaluation and prediction of streambank erosion processes within the Town Creek watershed (TCW) in Mississippi. The hypothesis of the study was that streambank erosion is an important mechanism driving sediment supply into the streams and an important portion of the sediment budget for the TCW. A combination of <em>in situ</em> monitoring, geomorphic characterization methods and modeling was performed on different locations along the TCW to quantify the contribution of streambanks to stream sediment loads and better understand the processes of streambank erosion. From the results streambank instability was prevalent and highly erodible materials of streambanks are an important potential source of sediment through the entire watershed. Streambanks predominantly lost materials through gravitational failures and removal of failed sediments by hydraulic forces along the channel headwaters. These geomorphic processes could supply a considerable amount of the estimated 1,000,000 Mg of sediment annually exported from the entire watershed. Headwaters were commonly represented as incised channels near agricultural areas. Annual top streambank retreat occurred up to 2.7 m and contributed annual sediment loads ranged from 0.15 to 28.5 Mg per m-stream. Both assessments were based on repeated measured cross section surveys performed from February 2009 to March 2010. The USDA computational model CONCEPTS (Conservational Channel Evolution and Pollutant transport System) was evaluated on an incised reach of TCW to assess model performance and capability to simulate spatial and temporal changes along the study reach. CONCEPTS accurately predicted the time of occurrence and magnitude of top streambank retreat and failures of streambanks along the modeled reach. Results from field measurements and modeling offered important insights into the relative effects of streambank erosion on the sediment budget for TCW. Reduction of suspended sediment loads should focus on the attenuation of geomorphic processes and stabilization of reaches near agricultural lands at the headwaters within the watershed.
Identifying Fish Guilds Relative to Water Quality and Depth in Oxbow Lakes of the Mississippi Alluvial Valley
Year: Authors: Goetz D., Kröger R., Miranda L.E.
The Mississippi Alluvial Valley (MAV) contains a myriad of oxbow lakes from remnant braided river channels that are constantly being exposed to high nutrient and sediment loads via agricultural runoff. These increased sediment and nutrient loads have deleterious effects on water quality, and potentially have intensified variability in fish assemblages. Recent studies of fish assemblages in oxbow lakes of the MAV have provided strong evidence regarding the driving forces behind fish community organization. Depth and land-use have been identified as key variables influencing fish assemblages. Furthermore, water quality in oxbow lakes is known to vary across environmental gradients though has not been linked to fish community structure, specifically pollution tolerant or intolerant guilds. Preliminary data indicates that diel fluctuations in DO, temperature and pH vary considerably between deep and shallow habitats within the same oxbow lake. Additionally, a dominance by tolerant fish species have been observed in shallow back water areas of deep lakes that harbor a diverse fish fauna, suggesting that stressful environments may harbor tolerant fish species and impede the survival of intolerant species. Measuring diel fluctuations in temperature, pH, and DO and using multivariate statistics to relate fish communities to water quality parameters, will likely determine if distinctly different fish guilds are inhabiting deep and shallow oxbow lakes of the MAV.
Assessing Water Balance Using a Hydrologic Model
Year: Authors: Duffy S., Parajuli P.
The availability of water within soil is fundamental to the success of agricultural, ranching, and forestry practices. The amount of water than is present within the soil column depends on climate, land use, land management practices, and soil characteristics. The objective of this study is to assess water balance parameters such as surface flow, soil moisture content, and water quality parameters using field studies and the Soil and Water Assessment Tool (SWAT) model simulations. <br /><br /> Two watersheds located in northeast (Town Creek, 1775.2 km<sup>2</sup>) and central (Upper Pearl River, 7,588 km<sup>2</sup>) Mississippi were chosen as the focus of this study. Soil samples from four fields of varying land use were collected monthly and analyzed to determine actual soil water content. Theoretical soil water content was predicted by developing two independent computational models using SWAT. The models were calibrated and validated using monthly stream flow data obtained from USGS gauging stations. Field-observed soil water content and model-predicted soil water content was analyzed statistically. Further model-simulated uncalibrated water balance and water quality outputs will be presented.
Sediment and Mercury Fate and Path Modeling in Weeks Bay, Alabama
Year: Authors: Sloan-Ziegler J., Camacho-Rincon R., Martin J., McAnally W.
Mercury, a naturally occurring element, is found in water, soil, and air and is released into the environment through natural sources and human activities. Mercury is subject to several physical and chemical processes in aquatic systems that impact its fate, transport, and toxicity to humans and aquatic life. Mercury bioaccumulates though the food chain and can eventually be ingested by humans though fish consumption. Mercury exposure can lead to negative effects such as risks to the nervous system, brain, lungs, heart, kidneys, and immune system. <br /><br /> Knowing the processes that can affect the fate and transport of mercury in waterbodies is fundamental for developing ecological restoration and prevention plans as well as for mitigating the potential threats to humans. <br /><br /> In this study, a mechanistic model based in the Water Quality Analysis Simulation Program (WASP) was implemented to support the analysis and understanding of the fate and transport of mercury in Weeks Bay, Alabama. Preliminary results indicate that the model is capable of representing the transport characteristics of the estuary and is, thus, potentially able to reproduce the long-term transport of mercury in the system. Current observed mercury data is limited; therefore, the current model can be used to aid in the formulation and development of future data collection programs focused on refining, calibrating, and validating the model.
Monitoring Success of Mississippi's Delta Nutrient Reduction Strategies—Steele Bayou
Year: Authors: Stocks S., Hicks M.
The Steele Bayou watershed (SBW) in the lower Mississippi Delta of northwestern Mississippi has been subjected to altered land and water resources for decades. Poor stream health in the SBW has been documented by several short-term studies, and the watershed is listed on the Mississippi Department of Environmental Quality section 303(d) List of Impaired Waters with causes of impairment being pesticides, organic enrichment/low dissolved oxygen, nutrients, and siltation. In the SBW, like many other areas in the Delta, there have been and continue to be numerous large and small scale efforts by land owners and State and Federal entities to reduce sediment and nutrient loadings. It is estimated that more than $15 million has been spent in the SBW for various conservation practices, not factoring in unknown private dollars by landowners. It is also estimated that combined Federal, State and private efforts have resulted in up to 50 percent of the Steele Bayou watershed being treated with various conservation practices. <br /><br /> An intensive monitoring network was implemented in 2008 through a multi-agency partnership. This monitoring network was designed to evaluate conditions at three nested scales: edge-of-field, in-stream, and outlet of the watershed. Data collected from the network will help define characteristics of a wide range of physical and chemical properties of water quality and will quantify the changes over time that result from the implementation of conservation measures. Preliminary evaluation of historical data compared to current data from the SBW suggests decreases in both sediment and nutrients. In addition to comparison of data between historical and current values, the current monitoring design will allow for a detailed analysis of loads and trends over time, at edge of field and at several locations along the main stem channel.
Assessment of Improved Sensors to Monitor Water Used for Irrigation in the Mississippi Delta
Year: Authors: Burt D.E.
The Mississippi River Valley alluvial (MRVA) aquifer spans seven states in the central part of the U.S. In northwestern Mississippi, the MRVA underlies a rich, agricultural region known locally as the Delta. Nearly all of the water used to irrigate crops in the Delta is withdrawn from the MRVA aquifer. As more and more wells are drilled to irrigate crops, the need to monitor the amount of water being pumped from the MRVA becomes more critical. Using technologies such as data loggers combined with improved sensors, the U.S. Geological Survey has partnered with the Yazoo-Mississippi Delta Joint Water Management District to monitor irrigation wells throughout the Delta. <br /><br /> Vibration and inductance sensors are being tested on a variety of pumping applications to obtain real-time data for the amount of time that pumps are applying water during the growing season. The sensors were evaluated on about 30 test wells during the 2011 growing season to determine their ability to accurately monitor pump usage based on powering up and down and overall run-time. Once pump usage is determined, and pump rates are measured using a non-intrusive flow meter, then a total water volume pumped at each well can be calculated. <br /><br /> Future plans are to calculate total water volume pumped from a network of wells throughout the Delta during the growing season. Selected permitted wells in every county in the Delta for each of the four main crop types—corn, cotton, rice, and soybean—will form the network. This network can then be used to estimate irrigation water use for all other permitted wells in the Delta, aggregated by crop type and county.
Comparison of Indigenous and Selected Pentachlorophenol (PCP) Degrading Bacterial Consortiums for Remediation of PCP Contaminated Groundwater
Year: Authors: Joshi V.V., Prewitt M.L., Borazjani H., Willeford K.
Pentachlorophenol (PCP) is a very toxic and recalcitrant compound which is commonly used in industrial and agricultural applications such as pesticides, leather tanning, pulp bleaching and wood preservatives. Its extensive use and improper disposal in the environment for more than sixty years has resulted in groundwater contamination, which is a very serious health and environmental issue. Previous studies have reported individual bacterial and fungal species that actively degrade the PCP. However in the environment there are many microorganisms present at sites of PCP contamination and few studies have focused on the microbial community involved in PCP degradation at these sites. Therefore the objective of this work is to compare PCP degradation by the indigenous bacterial community from PCP contaminated groundwater and customized groups of known PCP degrading bacteria. In this study, PCP contaminated groundwater samples will be collected from a former wood treatment site undergoing biosparging remediation. The experimental setup will include treatments of indigenous and known PCP degrading bacteria. Analyses for bacterial identification, gene expression and enzyme activity will be conducted during the degradation of PCP at different concentrations. Molecular identification will be carried out by cloning and sequencing of DNA extracted from these bacteria and real time PCR will be used for gene expression analysis of the PCP degrading genes: pcpB, pcpD, pcpC, pcpA and pcpE. Enzyme activity will be determined spectrophotometrically by monitoring substrate utilization over time. Statistical analysis of the data will be carried out by using the program SAS v. 9.2 to check the significant differences in PCP degradation by these bacterial consortiums. The results of this study should be beneficial for bioremediation of PCP in the environment.
Assessment of the Ecological Value of Low-Grade Weirs in Agricultural Drainage Ditches
Year: Authors: Poganski B., Kröger R.
Agricultural best management practices have been a common fixture in farm field landscapes for decades. Unfortunately, little scientific information documents ecological and economic benefits of implementing such practices. Recent literature has highlighted the ability of low-grade weirs placed in agricultural drainage ditches to decrease sediment and nutrient loads to downstream waters by altering ditch discharge rates and hydraulic residence time. Currently, knowledge of how these structures can affect agricultural landscape ecology, from the molecular to ecosystem level, is unknown. The aim of this research is to assess the ecological value of low-grade weirs as effective management practices in agricultural drainage ditches. Ecological value will be appraised based on the diversity and richness of organisms inhabiting such systems. Organismal communities were selected for evaluation because of their critical roles in nutrient cycling and exchange within aquatic food webs. Experimental organisms include aquatic vegetation, microbes, benthic macroinvertebrates, and fish. Sampling events will be conducted during the growing season (May-June) annually for 3 years in agricultural drainage ditches fitted with low-grade weirs in the upper Yazoo River Basin. Conducting the experiment during the specified time period increases the likelihood that water will be present in ephemeral ditches. Organism data will be compared to chemical sediment and water data collected at the study sites provided by an ongoing study that will continue on a parallel temporal scale. Investigating biologically diverse but systematically linked organisms, will not only supplement estimates of the total ecological value of low-grade weirs in drainage ditches, but analysis of individual groups of organisms will aid in predicting mechanistic effects of implementing such structures in heavily cultivated agricultural landscapes.
Preliminary Results from a New Ground-Water Network in Northeastern Mississippi
Year: Authors: Manning M.A., Rose C.E., Welch H.L., Coupe R.H.
In 2010, the U.S. Geological Survey established a new groundwater network to better understand the influence of agricultural land use on shallow groundwater quality. The areal extent of the study spans from southwestern Tennessee southward through the middle of northern Mississippi. A 30 well network overlays the basic recharge area that conforms along the eastern outcrop boundary of the Middle Claiborne Group, (Sparta Sand) within Tennessee and Mississippi. Well locations were randomly selected using a grid of 30 polygons generated by a geographical information system (GIS) model. Monitoring- well locations were then selected for each GIS-generated polygon that best fit both agricultural land use, and location to the outcrop area. These areas of outcrop for the Sparta Sand provide a hydrologic connection between the aquifer, and surface-water sources such as rivers, lakes, and rainfall runoff. This study will investigate the shallow groundwater quality of the Sparta waters on the eastern edge of the formation that could be altered by agricultural land use and will document any unfavorable compounds that may be carried into the aquifer. <br /><br /> During the fall of 2010, 15 of the new 30 well network were drilled and established on private properties located in northeastern Mississippi. These new monitoring wells were installed using a rotary drilling-type rig until the first water was identified. Using historical data, potentiometric surfaces were estimated to range from zero (land-surface) to about 30 feet below land surface. During the initial well drilling, the first water was encountered anywhere from 12 to 40 feet below land surface. All of the wells were screened at a 10 foot interval from the bottom of the well. Each well screen was set within mixed marine/deltaic facies consisting mostly of sand to sandy silty clays which are considered consistent with most Sparta Sands. Most of the wells were drilled within an area consisting of a least 60 percent or more local agricultural land-use. The locations were selected because the landowners were interested in the study, allowed accesses to their property, and they possessed land that had active agricultural activities that included corn, cotton, and /or soybeans. <br /><br /> The lower extent of the two-state study area was sampled for groundwater quality from March through April 2011. Water samples were analyzed for a wide range of constituents, including but not limited to trace elements, inorganics, nutrients, dissolved gases, tritium, and a full spectrum of pesticide compounds. The well network will be re-visited annually to monitor water levels, and a subset of five wells will be sampled every other year. Future plans are to re-sample the entire network for water-quality trends on a 10-year rotation. Land-use surveys were conducted within a 500-meter radius of each well to determine the current land use, and to provide a baseline for future land-use changes.
Effects of Immobilizing Agents on Surface Runoff Water Quality from Bermudagrass Sod Fertilized with Broiler Litter
Year: Authors: Sheng J., Adeli A., Brooks J.P., McLaughlin M.R.
Surface broadcasting is the common method for applying poultry litter on perennial forages, but this application method concentrates nutrients and pathogenic microorganisms at the soil surface where they are vulnerable to runoff water. The potential impairment of surface water from soluble nutrients, particularly N and P, metals such as copper (Cu) and Zinc (Zn), and pathogenic microorganism contained in broiler litter are of concern. Management practices that minimize contaminants in surface runoff water are environmentally desirable. A greenhouse study was conducted using rainfall simulation to determine the effects of immobilizing agents, such as FGD (flue gas desulfurization) gypsum (a residue from coal combustion) and biochar, on manure nutrients and fecal bacteria in runoff from bermudagrass sod. The experimental design was a randomized complete block with seven treatments and three replications. Treatments included a control (no litter), and broiler litter (either wood shavings or rice hulls) at the rate of 9 Mg ha<sup>-1</sup>, in all combinations with and without FGD or biochar. Rainfall was delivered at an average intensity of 75 mm h<sup>-1</sup> with a total of four rain events. Runoff was collected in 250-ml sterile plastic bottles. Runoff samples were immediately transferred to the lab for microbial and nutrient analyses. Nitrate and ammonium were determined on a Lachat. Dissolved reactive P and metals were determined in filtered (0.45 µm filter) runoff samples. Unfiltered runoff samples were digested and analyzed for total nutrient concentrations using ICP). The results indicated that application of broiler litter in combination with FGD gypsum to bermudagrass significantly reduced runoff total dissolved organic C (DOC), total N, dissolved reactive P (DRP), Cu and Zn by 16, 30, 61, 73 and 13%, respectively, compared to broiler litter alone, regardless of litter type. Biochar had no effect on reducing soluble nutrients in surface runoff. Treatments did not affect culturable bacterial levels in runoff. Detailed information will be discussed.
Hydrologic Regimes of Bottomland Hardwood Forests in the Mississippi Alluvial Valley and Gulf Coastal Plain and the Impact on Red Oak Acorn Production
Year: Authors: Sloan J., Hatten J.
Red oak (<em>Quercus</em> spp.; Subgenus <em>Erythrobalanus</em>) acorns provide a major food source for many species of wildlife such as ducks, white-tailed deer (<em>Odocoileus virginianus</em>), and wild turkeys. Acorns are also important for the regeneration of these forests. The production of acorns is sporadic and the cause of this is not completely known or understood. Red oaks are prevalent in bottomland hardwood forests throughout the Mississippi Alluvial Valley (MAV) and Gulf Coastal Plain (GCP) and these forests undergo extreme hydrological events annually, from being completely inundated in the winter and spring to very dry in the summer. This study will examine the hydrology and soils of bottomland hardwood systems and the control they have on acorn production. Data has been collected at six sites, covering five states in the MAV and GCP. A well placed at each site was used to measure hydroperiod with an In-Situ Inc. LevelTROLL 300 and an In-Situ Inc. BaroTROLL. With these wells both ground water and surface water were measured. Organic matter input was measured using 10 porcelain sediment tiles at five of the sites and 20 porcelain sediment tiles at one site. Organic matter content of deposited sediment was determined by loss on ignition. Acorn production data was measured at 20 plots per site during the fall and winter of 2011/2012 and will be measured again in the fall and winter of 2012/2013. We will present preliminary hydrology, sedimentation, and organic matter accumulation data collected from September, 2011-February 2012.
Efficacy of Manufactured Wood Shavings to Mitigate Marsh Land Impacts Associated With Deep Water Oil Spills
Year: Authors: Seale R.D., Borazjani H.
Use of pine shaving to remove oil from seawater and sandy beaches during spill was evaluated. Two identical microcosms capable of simulating tidal waves were constructed. Shavings were applied in three different spill scenarios; 1): over clean sand before tide, 2): over contaminated sands after tide, and 3): over oil covered seawater. Saudi Arabian sweet crude was used for this study. Shavings adsorbed significant amounts of oil in all three cases from oil contaminated water and sands. Shavings spread over the contaminated seawater surface contained the highest amount of oil adsorption from seawater and the least amount of sand contamination. This method of application seems to provide the most efficient and practical approach for quick removal of oil and spent shaving from seawater with minimal contamination of beaches or marshes. The high number of petroleum acclimated bacteria in seawater are able to biodegrade the leftover residual hydrocarbons.
Soil Moisture and Watershed Assessment to Predict Wildfire Occurrences in the Southeast of United States
Year: Authors: Arias-Araujo E., Diaz-Ramirez J., Cooke W.
Wildfires occurrences are frequent in the Southeast of United States (US) and it has become a major concern in this region. The purpose of this study is to determine the effect that soil moisture (SW) level and basin water- balance values (BWB) have over summer-wildfires occurrences in the Southeast of US which encompasses Texas, Louisiana, Oklahoma, Mississippi, Alabama, Tennessee, Georgia, Florida, South Carolina and North Carolina. Quantifying, analyzing and processing the spatial and temporal distribution of SW and BWB could be an effective method for modeling, managing and preventing potential wildfire occurrences. Most of the studies related with this topic have been done to assess the causes and ecological conditions that aid the beginning of wildfires; however, there has not been found studies that integrate SW and BWB to evaluate and predict the wildfires occurrences. Hydrological models such Soil Water Assessment Tools (SWAT) and Hydrological Simulation Program--Fortran (HSPF) are being used as tools to evaluate, compare and simulate watershed water-flow and SW outputs at specific locations where the density of wildfires occurrences are elevated, medium and low; the purpose of this analysis is to contrast temporally and spatially the three scenarios. To evaluate the complete Southeast of US a simpler soil water-balance model is being utilized because of the large extension of study area. SWAT and/or HSPF require data intensive inputs and extensive parameterization thus these models have limited capabilities to process the complete Southeast region. ArcGIS and MATLAB software have being used to compile, prepare and analyze data. Wildfire data, Digital Elevation Models (DEMs), NASA -Land Information System (LIS) gridded binary (GRIB) data, National Land Cover Data (nlcd), STASTGO soil units (USDA-NRCS), USGS-stream-gauges and NOAA Doppler data (precipitation) is being used in the assessment. The final product will be Graphical user interface (GUI) that permits the modeling and prediction the wildfires occurrences in the southeast of US. This GUI will be distributed and shared with governmental agencies and private organizations associated with Forest and Land management. This project is being funded by National Aeronautics and Space Administration (NASA).
Evaluating a Vegetated Filter Strip in an Agricultural Field
Year: Authors: Young A.
The use of best management practices and low impact development strategies have become common in recent years, leading to the need for the creation of hydrologic models to predict their behavior and effectiveness. A vegetated filter strip at the South Farm Research Park at Mississippi State University was used to test two of these models: the Hydrologic Simulation Program-FORTRAN Best Management Practices Editor (HSPF BMPrac) and the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN). Water samples were taken during the Spring of 2011 and tested for sediments and nutrients; HSPF was used for computing flows, sediments, and nutrients. The filter strip was not effective at pollutant removal with removal efficiency rates of 68.1, 91.7, 86.3, and 115.4 percent for total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and dissolved phosphorus (DP) respectively. Calibration of HSPF was successful for TSS with a R<sup>2</sup> value of 0.52; nutrients were not as successful with R<sup>2</sup> values of 0.11 and 0.43 for TN and TP. HSPF's BMP Practice Editor demonstrated an drastic over prediction of pollutant removal. Modeling of the VFS in SUSTAIN was not a success due to technical failures preventing the model from running.<br /><a href="/pdf/2012_young_pres.pdf">Download the presentation</a>
Sediment and Nutrients Loadings from the Upper Pearl River Watershed
Year: Authors: Parajuli P.B.
Sediment and nutrients loading from the non-point sources of agricultural and non-agricultural activities contribute to water quality degradation. Developing Total Maximum Daily Loads (TMDLs) for the sediment and nutrients require quantifying pollutant load contribution from each potential source. Quantifying pollutant loads from each source will help in developing pollutants reduction strategies to meet applicable water quality standards. The objective of this research was to monitor sediment and nutrients concentrations and quantify daily, monthly and annual pollutant loadings from the Upper Pearl River watershed (UPRW-7,885 km<sup>2</sup>) in east-central Mississippi. Analysis of average NCDC rainfall, USGS stream flows, observed sediment, and nutrient data from the watershed will be presented. Preliminary results from the model simulations will also be presented using appropriate statistics.
An Approach for Low Flow Selection in Water Resource Management
Year: Authors: Ouyang Y.
Low flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach, was developed based on the frequent low category used in minimum flows and/or levels programs. This approach was then compared to the conventional 7Q10 approach for low flow selections prior to its applications, using the USGS flow data from the freshwater environment (Big Sunflower River, Mississippi) as well as from the estuarine environment (St. Johns River, Florida). Unlike the FL approach that is associated with the biological and ecological impacts, the 7Q10 approach could lead to the selections of extremely low flows (e.g., near-zero flows) that may hinder its use for establishing criteria to prevent streams from significant harm to biological and ecological communities. Additionally, the 7Q10 approach could not be used when the period of data records is less than 10 years while this is not the case for the FL approach. Results from both approaches showed that the low flows from the Big Sunflower River and the St. Johns River decreased as time elapsed, demonstrating that these two rivers have become drier during the last several decades with a potential of salted water intrusion to the St. Johns River. Results from the FL approach further revealed that the recurrence probability of low flow increased while the recurrence interval of low flow decreased as time elapsed in both rivers, indicating that low flows occurred more frequent in these rivers as time elapsed. This report suggests that the FL approach, developed in this study, is a useful alternative for low flow selections in addition to the 7Q10 approach.<br /><a href="/pdf/2012_ouyang_pres.pdf">Download the presentation.</a>
An Analysis of Factors Influencing Capacity Development of Public Water Systems in Mississippi
Year: Authors: Barefield A., Tack J.
The Safe Drinking Water Act Amendments of 1996 (SDWA) mandated the implementation of capacity development strategies to avoid the withholding of Drinking Water State Revolving Fund monies. In particular, section 1420 defined the two capacity enhancement foci as (1) ensuring that new community and non-transient water systems demonstrate sufficient financial, managerial and technical capacity to achieve authorization and (2) developing an implementation strategy to assist currently operating water systems with acquiring and maintaining these same capacity components. <br /><br /> As the state's primacy agency, the Mississippi State Department of Health-Bureau of Public Water Supply (MSDH-BPWS) has developed a mandatory survey instrument that contains three sections corresponding to the enumerated capacity development mandates. MSDH-BPWS regional engineers administer this survey to all community and non-transient water systems in the state. MSDH-BPWS also utilizes a portion of Drinking Water State Revolving Fund monies to fund capacity development programs, such as the Peer Review program. The Mississippi State University Extension Service implements this program that utilizes a team of certified waterworks operators from high performing systems to make site visits to poorer performing systems and providing advice and technical assistance in improving capacity development scores. <br /><br /> The purpose of this paper is to assess the effectiveness of the Peer Review program in increasing capacity development scores and to assess a number of other factors that may have significant influence on a particular system's capacity development. An intertemporal binomial dependent variable regression model is constructed to determine the marginal effects of several firm-level managerial and regional socioeconomic factors in influencing the success of public water systems in increasing capacity assessment scores to acceptable levels.<br /><a href="/pdf/2012_barefield_pres.pdf">Download the presentation</a>
The Influence of the Mitchell Rate Structure on Community Drinking Water Consumption and Customer Fairness
Year: Authors: Barrett J.
Public water systems have come to accept standards in relation to rate structures to support their respective drinking water systems without comparing the cost to customer conservation or equity. The current rate structures have been adopted without substantive support for why this is the rate structure to utilize. The Mitchell (single) rate structure is a rate structure that highly promotes fairness among the customer base in relation to the cost of drinking water in comparison to the amount of revenue produced by the customer base. The Mitchell (single) rate structure also triggers conservative drinking water consumption practices amongst different socioeconomic strata. A new rate structure can be an alternative answer to the rising infrastructure cost and drinking water supply concerns. In this presentation, I will look to explain the impacts of the Mitchell (single) rate structure on public drinking water systems and the possible ramifications a new rates structure may bring.<br /><a href="/pdf/2012_barrett_pres.pdf">Download the presentation</a>
Financial Sustainability of Water Treatment and Distribution: Using a Public Private Partnership Toolkit to Evaluate Project Costs
Year: Authors: Werner R.A., Surbeck C.
With population growth and an increasing need for water supply and distribution, innovative ways to sustainably finance capital, operation, and maintenance costs of water projects must be found. A Public Private Partnership (PPP) between government and one or more private companies is an underused means of financing such projects. PPPs in the United States are common in the energy and solid waste industries. However, in the water sector, governments have been the entities solely responsible for funding water services. PPPs in water projects would enable a larger variety of capital investments and a balanced share of risk between government and private companies. Further, PPPs enable public services to be provided when there are public budget constraints. <br /><br /> The principal objective of this presentation is to show scenarios in which PPPs are beneficial for funding water projects. The analysis will include data from municipalities in the state of Mississippi, and results from a case study will be reported. The method used will be a toolkit software developed by The World Bank for use in road and highway projects. This existing toolkit, which has been applied to PPP projects worldwide, will be adapted for the water sector. For example, existing input parameters, such as average daily traffic and toll rate per vehicle, will be changed to water-related parameters, such as average daily water use and water use fees per household. <br /><br /> Overall, the goal of a PPP project in the water sector is a sustainable investment for both the government and private entities in terms of balance of risk and financial return on investment.
Monitoring Success of Mississippi’s Delta Nutrient Reduction Strategies
Year: Authors: Hicks M., Stocks S., Wright J.
Nutrient reduction strategies are being implemented in northwestern Mississippi, an area locally referred to as the Mississippi Delta, in response to Action Plans of the Mississippi River/Gulf of Mexico Hypoxia Task Force and the Gulf of Mexico Alliance, which call for reduction of nutrients to the Gulf of Mexico. As part of the nutrient reduction efforts, it is important to understand and answer several key questions such as what level reductions are achievable and what reductions are required to protect the health of Delta waters. To gain a scientific understanding of these questions, a comprehensive monitoring and data collection plan was developed by a consortia of Federal, State, and local agencies and is being applied throughout the Delta. Monitoring will document changes in nutrient concentrations and loads that occur at each of three nested scales—edge-of-field, in-stream, and outlet of the watershed —following the implementation of a suite of BMPs. <br /><br /> As part of the implementation of the comprehensive plan, the U.S. Geological Survey began monitoring in the spring of 2010 in selected Delta watersheds and will continue for several years to detect changes over time. Two of the watersheds where monitoring is taking place include Harris Bayou and Porters Bayou in the upper part of the Big Sunflower River Bain. Implementation of best management practices (BMPs) is complete in Harris Bayou watershed, and post-implementation monitoring has begun. Pre-implementation monitoring is continuing in Porters Bayou as implementation of BMPs has yet to begin. <br /><br /> Monitoring in these watersheds includes collection of flow and water-quality samples throughout the entire year, during storms and on a regular fixed schedule. To evaluate changes, a before-and-after and a paired-watershed approach are being used. Ecosystem characteristics being monitored and evaluated include, but are not limited to, various physical, chemical and biological properties such as nutrient concentrations, sediment concentrations, dissolved oxygen dynamics, chlorophyll-<em>a</em> concentrations, streamflow, physical habitat, and biological community assemblages.<br /><a href="/pdf/2012_hicks_pres.pdf">Download the presentation</a>
Preliminary Sediment Accumulation and Phosphorus Retention Behind Low Grade Weirs in the Mississippi Delta
Year: Authors: Usborne E., Kröger R.
Agricultural phosphorus (P) loads, carried by surface runoff through ditches, contribute to eutrophication. Low grade rip rap weirs potentially reduce P from entering primary aquatic systems by slowing water flow through drainage ditches, allowing sediments to settle out and P to sorb to soil. Due to the relatively new application of weirs in Lower Mississippi Alluvial Valley drainage ditches, their effects over time are not understood. Weirs have the potential to alter the pH and hydraulic residence time within the ditch system, thereby affecting P retention by ditch soils. Three weirs and a control have been monitored monthly from the time of installation for one year in order to track changes in P bioavailability ratios and sediment deposition rates. Sediment depth was recorded using a permanent reference marker located behind the weir and P fractions were measured on collected sediment samples. Loosely bound P and iron phosphate were considered bioavailable while reductant-soluble P and aluminum phosphate were considered non-bioavailable. Locations that are losing sediment coincide with increasing bioavailability ratios and locations that are accumulating sediment have declining bioavailability ratios. Predicting time periods between soil P saturation and sediment accumulation limits will allow us to inform farm managers of optimal times to dredge ditches for greatest phosphorus retention efficiency.
Rule Curves in Flood Control Reservoirs: A Historical and Procedural Analysis
Year: Authors: Mower E., Miranda L.E.
The U.S. Army Corps of Engineers (USACE) manages 11 million ha of federal land and water including hundreds of multi-purpose reservoirs. Managing the water regime in many of these reservoirs requires establishing seasonal targets in water levels (i.e. rule curves) that are dependent on regional precipitation patterns and water demands from user groups. Rule curves in Northern Mississippi reservoirs were established in 1967 as an answer to increased interest in multi-purpose water storage. Rule curves have been modified in past years attempting to balance various environmental concerns such as emphasis on fish and wildlife management mandated in USACE reservoirs by federal legislation, and water needs such as flood control and agriculture use. The processes and challenges associated with developing and amending rule curves are complicated and generally unknown to most fish and wildlife managers and user groups. Informing managers and user groups about the process required could lead to effective communication, management, research, and collaboration. Thus we sought to review the processes, policies and laws the USACE follows in developing and amending rule curves that govern water levels, focusing on the four large flood control reservoirs in the Upper Yazoo Basin. To this end we reviewed the history of the rule curves, as well federal policies and laws governing them. We obtained our information from a literature review and interviews with agency personnel having current or past involvement in managing these flood control reservoirs. Congressional authorization, feasibility studies and justification studies are some requirements that must be met before a rule curve can be established or modified. National Environmental Policy compliance must be shown, as well as flood risk impacts both upstream and downstream for flood control reservoirs. Magnitude of the rule curve change determines congressional involvement in amending rule curves. Although our results are preliminary, they provide a window into a little-understood but important component of fish and wildlife management in reservoirs.
The Arkansas Discovery Farms Program
Year: Authors: Daniels M.B., Sharpley A.
Discovery Farms are privately owned farms that have volunteered to help with on-farm research, verification, and demonstration regarding farming's impact on the environment and natural resource sustainability. We currently have six Discovery farms at five counties of the State; including a poultry farm in Washington County, a beef cattle operation in Conway County, a rice-soybean and corn operation in Arkansas County, two adjacent rice-soybean operations in Cross County and a cotton farm in Desha County. We are currently collecting water use and water quality data from individual fields on each of these farms utilizing automated water monitoring stations. These stations include automated ISCO samplers equipped with rain gauges, pressure transducers in conjunction with edge-of-field H-flumes, pipes or weir flow structures. In Washington County, we are monitoring runoff originating immediately near poultry houses due to concerns with spillage during house clean out and dust accumulation from tunnel ventilation. We are also quantifying the nutrient and sediment remedial efficiencies of capturing runoff in a farm pond and an un-grazed filter strip. In Conway County, we are assessing runoff from pastures and the ability of a wetland to capture and assimilate nutrients. In Arkansas County, we are examining three eighty-acre rice fields with different water management practices, a corn field and runoff from 1,200 acres that drains back to an irrigation reservoir. In Cross County, we are monitoring a sixty-five acre rice field under conventional production and a twenty-three acre soybean field under conservation tillage. Finally, in Desha County, we are the effects of conservation tillage and cover crops on nutrient and sediment loss from three eight-acre fields in cotton. However, the Arkansas Discovery Farms program is not just about monitoring but just as importantly, engaging farmers to take ownership in environmental issues facing agriculture. This paper will discuss the development, guidance, principals and goals of the Arkansas Discovery Farm program.<br /><a href="/pdf/2012_daniels_pres.pdf">Download the presentation</a>
Holitoblichi: A Celebration of the North Mississippi Hills
Year: Authors: English J.R.
Utilizing the Choctaw Indian word for "celebrate" as its name, Holitoblichi intends to celebrate the heritage and inspire the future of the north Mississippi Hills through the stewardship of its unique cultural and natural environment. This project transforms nearly 350 acres adjacent to the new Toyota manufacturing plant in Blue Springs, Mississippi into a regional amenity with a rich array of uses. From stormwater management and bioremediation to stream channel restoration and native habitat revitalization, from experiential learning and community-building facilities to sustainable agriculture and recreation, the project combines many threads into one comprehensive story. Guiding the design are three principles: 1) to express the three components of sustainable development (environment, economy, society) in every aspect of the design; 2) to weave together agricultural, environmental, and industrial and showcase the symbiotic relationships between them; and 3) to evoke a sense of "the new old," pulling culture from the past and the present into an innovative and resilient future. Conceptually, two poles anchor the design: environment and culture. Throughout the space between, the interconnections between the two poles are explored. From practicing agriculture in collaboration with nature to experiencing the blues in the environment that set its tone, Holitoblichi is an example of how a mutually beneficial relationship between man and nature can be cultivated.
Adapting Portland’s Stormwater Approach to Other U.S. Cities
Year: Authors: Gallo W.C., Overbey E.
The Pacific Northwest, specifically Portland, OR, has become a recognized leader in progressive and creative stormwater management practices in the United States. Its projects have received numerous design awards and recognition based on their innovative approach to manage stormwater for both quality and quantity using primarily small-scale vegetated facilities. Designers throughout the country use Portland as a model of what could be done elsewhere, however there are numerous differences that have to be accounted for. <br /><br /> The presentation will explore the inherent differences between stormwater management in the Pacific Northwest and the rest of the United States, and also the opportunities that can be shared with the rest of the country. The research focuses on Portland's practice of providing a simplified sizing factor for small scale best management practices. The researchers re-created Portland's sizing factors and then modified the variables to reflect a range of locations elsewhere in the United States. <br /><br /> Through this approach, the study highlights just how different, and more complicated, it is to apply small scale best management practices to other parts of the country. However, the differences, while in some instances are quite significant, point to opportunities to design future facilities around the specific needs of each location. This will be demonstrated by illustrating how a built work in Portland could be modified to meet other regions' climatic differences. <br /><br /> Armed with a better understanding of what it means to take the Pacific Northwest's triumphs and apply them to the rest of the country, the study hopes to allow designers to more meaningfully engage clients and engineers in a dialogue about specific issues and opportunities related to adapting Portland approaches to their own watershed.<br /><a href="/pdf/2012_gallo_pres.pdf">Download the presentation</a>
Policy Approaches to Stormwater Facility Sizing and Sustainable Site Design
Year: Authors: Overbey E., Gallo W.C.
A difficult challenge in implementing sustainable stormwater facilities is navigating stormwater policies designed to use complex stormwater models to size large detention basins. The presentation explores unique stormwater facility sizing approaches that have been used and modified for over ten years by landscape architects, architects and civil engineers in Portland, Oregon. Through a survey of design professionals, the research highlights the opportunities for policy to influence where and how stormwater facilities are incorporated into the design process. <br /><br /> The Portland Stormwater Management Manual (SWMM) primarily utilizes two approaches to meet the city's stormwater requirements. The Simplified Approach uses simple sizing factors accompanied by standard design details and specifications to streamline the process. Alternatively, the Presumptive Approach utilizes a unique sizing calculator that allows for maximum design flexibility and control of an array of best management practices. Both of these approaches promote multiple, small-scaled facilities that infiltrate and manage stormwater as close to where it falls as possible. <br /><br /> Results of the survey indicate that design professionals differ on how they utilize sizing tools in the design process. Art based disciplines lean toward the Simplified Approach that allows exploration of multiple solutions early in the design process, while engineers tend to lean toward the more robust Presumptive Approach, allowing refinement of the facility design. <br /><br /> The new and evolving paradigm of sustainable stormwater management can be shaped by policies that are designed specifically for implementation of small-scaled infiltration facilities. By simplifying the sizing process, these tools allow designers to use facilities as an integral part of overall site design. However, simplifying the sizing methodology is not a shortcut for simplifying design of the individual facility which requires careful consideration and refinement to meet specific needs of the site.
Sources and Yield of Dissolved Inorganic and Organic Constituents in Headwater Streams of the Upper Gulf Coastal Plain, Mississippi
Year: Authors: Mangum C., Hatten J., Dewey J., Choi B.
Mississippi has more than 8 million hectares of land in active forest management, much of which is in headwater watersheds. Headwater systems contribute water and initiate dissolved material export to downstream fluvial environments. Nutrients, such as nitrogen and dissolved organic carbon (DOC), are constituents that frequently lead to impaired rivers in Mississippi. This study analyzes event data from 4 ephemeral (1.8-3.8 ha) and 1 perennial (32 ha) forested headwater system in Upper Gulf Coastal Plain, Mississippi over a 15 month period. We measured dissolved inorganic and organic constituents in samples collected during storm and baseflow conditions. We calculated the flux of nitrate, dissolved organic nitrogen (DON) and phosphorus with average kilograms per hectares per year yields of 0.48, 7.83 and 0.25 respectively. We also used an end member mixing model to determine the source of water and compared those results with nutrient fluxes during both storm and baseflow conditions. The data show that dissolved constituents are primarily mobilized during the rising limb of storm events. The source of these materials appears to be shallow mineral soil horizons (A horizons). In our presentation we will discuss how the source of water interacts with flux of nitrogen and implications for forest management and downstream environments.<br /><a href="/pdf/2012_mangum_pres.pdf">Download the presentation</a>
Using Acoustic Measurements as a Surrogate Technique for Measuring Sediment Transport
Year: Authors: Chambers J., Kleinert D., Carpenter B., Goodwiller B., Wren D., Kuhnle R.
The diversity in climate, topography, soil types, and cropping practices within the United States lends itself to numerous soil erosion and water contamination mechanisms. The measurement of sediments transported in waterways using acoustic techniques can provide valuable information which can support both systems for planning and assessment and the development of better erosion control technologies. The collaboration between the NCPA and USDA-ARS-NSL has focused on the development and evaluation of innovative acoustic hardware and measurement techniques to monitor sediment transport. Most current techniques are often prohibitively expensive and not easily adaptable for <em>in-situ</em> measurements. Furthermore, manual techniques are often spatially and temporally coarse, cannot easily monitor particle movement over time and could modify the evaluated particle size distribution since aggregates are often broken up in sample collection and handling. In contrast, acoustic techniques tend to be amenable to <em>in-situ</em> measurement, are less costly, less invasive, and allow for long-term monitoring. The presentation will provide a survey of our work on using acoustics for monitoring sediment transport. This includes near bed, suspended, sand sized particles (100-1000 micron), clays and silts (0.1 – 64 micron diameter particles) which tend to be mixed uniformly throughout the water column along with future plans to investigate kinetic energy impact plates to monitor gravel bedload movement.
Technologies and Methods to Aid the Adoption of PHAUCET Irrigation in the Mississippi Delta
Year: Authors: Powers S.
Conservation is one of the keys to balancing the water budget of the Mississippi Delta's Alluvial Aquifer. As more and more farmed acres in the Delta are being irrigated every year, the use of new and existing conservation practices in the application of that water is imperative. While high value, expensive projects such as the installation of surface water reservoirs and tail water recovery systems demonstrate great groundwater savings potential, there are many other sensible and more economic ways to conserve the Delta's water resources. Among those options is the use of the PHAUCET Irrigation Program. PHAUCET is a computer program originally written by the USDA-NRCS for use with furrow irrigation of row crops using poly pipe. Its primary function is to generate a range of hole sizes for each irrigating set that will increase the uniformity of each round of irrigation. This increased uniformity allows irrigators to more accurately time irrigations, leading to a more easily managed irrigation cycle. With the PHAUCET Program, however, there are a number of variables users must input in order for the program to generate its suggested hole sizes. These variables include the flow rate of the well, hole spacing along the poly pipe, the elevation changes of the poly pipe, poly pipe size, the number of holes for each watered furrow, set lengths, and row lengths. While most of these variables are known to growers, three of them can be more difficult to obtain. Flow rates, elevation changes, and row lengths can all three present problems to growers when they are working to implement the program. This paper will look at different technologies and methods that have the potential to aid users in the collection and use of the lesser known variables.
Modeling the Potential for Replacing Groundwater with Surface Water for Irrigation by Using On-Farm Storage Reservoirs in the Mississippi Delta
Year: Authors: Thornton R.F., Pote J.W., Wax C.L.
A groundwater conservation strategy is proposed in this research—the use of surface water in lieu of groundwater. This can be achieved through the construction of on-farm surface impoundments, which may be as simple as large ditches which will serve to capture precipitation and tailwater. Previous research shows the effectiveness of using stream water in lieu of groundwater on fields located within one-quarter mile of a stream, and the effectiveness of capturing rainfall in catfish ponds. This research proposes another form of surface water capture—that of on-farm storage reservoirs. <br /><br /> A model was developed for optimizing the size of on-site water retention structures (ditches) to capture rainfall on agricultural fields in the Mississippi Delta. The climatological driver for the model is precipitation minus evaporation, which is then adjusted by a crop coefficient to produce an irrigation demand value based on the age of the crop. The model uses long-term weather records (50 years of daily data) to estimate daily values of these climatological inputs, which are then summed to weeks through the year. Total field irrigation demand, ditch demand, ditch volume, overflow, and ground water used are outputs of the model, calculated according to specified field size and ditch volume. The percentage of required irrigation demand that is met by rain stored in the ditch is calculated weekly for the entire growing season. <br /><br /> Field acreage, runoff coefficient, ditch acreage, and ditch depth are interactive inputs in the model. Outputs of the model recalculate as inputs are changed. Optimization is achieved when groundwater use is minimized, annual overflow is minimized, and the smallest possible amount of the field is used for the ditch. Previous research assessed the impact of crop type and irrigation system on aquifer volume and showed that the aquifer could be reduced in volume by as much as 1,500,000 A-F over the next 50 years under current practices. This study shows that if only 10% of Delta producers adopted on-farm surface water storage for irrigation, that decline in volume in the aquifer could be reduced to 100,000 A-F over the same time period. <br /><br />
Water-Conserving Irrigation Systems for Furrow & Flood Irrigated Crops in the Mississippi Delta
Year: Authors: Massey J.H.
The goal of this project was to determine the feasibility of using multiple inlet plus intermittent irrigation to reduce water and energy use in Mid-south rice irrigation. Intermittent rice flooding improves rainfall capture and reduces over-pumping by maintaining rice flood heights at less-than-full levels. Depending on soil conditions, weather, and crop stage, the targeted intermittent pumping pattern allows the flood to naturally subside over a period of five to ten days before re-initiating irrigation, resulting in a fully saturated (not dry) soil surface. Field studies are being conducted at four Mississippi producer locations location in Boliver, Coahoma, and Sunflower counties in the Mississippi River Valley delta. Seasonal water use was measured using flow meters in commercial rice fields ranging in size from ~30 to 70 acres. Rainfall inputs were determined using rain gauges at each field location. Rough rice yield and grain quality determined for the upper and lower portions of each paddy of each field were not different, indicating that intermittent flooding does not result in agronomic losses relative to continuous flood. The studies show that when coupled with multiple inlet irrigation, intermittent rice irrigation uses ~20% less water than multiple inlet irrigation alone and only ~5% more than zero-grade irrigation. Having no slope, zero-grade fields are the 'gold standard' for Mid-south rice production in terms of water use. The advantage of the intermittent flood over zero-grade is that water-logging of rotational crops often associated with zero-grade fields is avoided. Rice is typically grown with soybean in a 1-yr rice, 2-yr soybean rotation. The presentation will also summarize results from using the USDA's Phaucet irrigation optimization program designed to improve soybean irrigation efficiency.<br /><a href="/pdf/2012_massey_pres.pdf">Download the presentation</a>
Best Management Practices in the MS Delta: What Are We Learning?
Year: Authors: Kröger R., Prevost J.D., Cooke T.
Agricultural best management practices (BMPs) can help reduce nutrient and sediment concentrations and loads leaving farm fields, which in turn can reduce negative impacts on downstream aquatic systems. For nearly three decades, significant federal investment in technical and financial assistance has been provided to implement farm BMPs. But few conservation programs attempt to estimate the amount of nutrient and sediment reduction resulting from cost-shared practices, let alone potential positive effect on local or regional water quality. This talk will encompass numerous ongoing and published scientific evaluations of BMPs within the MS Delta and the Lower Mississippi Alluvial Valley (LMAV). A review of BMPs within the LMAV highlighted only 18 articles (9 BMPs) that provided BMP efficiencies that met specific criteria of (a) row-crop agriculture, (b) clay/silt loam soils, (c) slopes 0-5%, and (d) occurred within the LMAV. The majority of the nine key BMPs for the LMAV provided significant nutrient reductions ranging from 15–100%. Field studies of innovative management practices such as low-grade weirs and slotted pipes have provided the very first nutrient reduction efficiency data for these structures in an agricultural field setting. Experimentally, it has been shown that weirs significantly increase nutrient reductions over conventionally drained systems. Field scale data on weirs is showing between 35-60% reductions for nitrate-N between inflow and outflow. Furthermore, the system documented a significant lag-effect that needs to be considered when evaluating BMP efficiencies. Slotted pipes have been quantified for the amount of sediment accumulation behind the structure. Observing sediment accumulation trends, (curvi-linear ; r<sup>2</sup> = 0.76) and applying a Von Bertalanffy non-linear model for sediment accumulation through time for the evaluated sites, highlights that highest sediment accumulation occurs with 235 d following installation. These sediment accumulation rates can be translated to sediment volume and mass, and when multiplied by the total phosphorus concentration of the sediment provides a potential for evaluating performance for this specific BMP.
Evaluation and Validation of a Decision Support System for Selection and Placement of BMPs in the Mississippi Delta
Year: Authors: Ortega-Achury S., Kröger R., Ramirez-Avila J., Diaz J.
Prevention and reduction of surface water pollution has been a matter of concern for decades, which has promoted the implementation of best management practices (BMPs) to ensure the protection of water resources. A considerable number of structural and non-structural BMPs have been developed to control hydrological processes and enhance pollutant load reduction at field and watershed scales. However, the selection of a specific BMP or the best combination of these practices and BMP placement are major challenges faced by decision makers. Recently, modeling tools have been presented as an effective alternative to support those challenges and to achieve cost-effectiveness in addressing environmental quality restoration and protection needs in different scenarios. USEPA has presented The System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN) model to be used by watershed and stormwater professionals to develop, evaluate and select optimal BMPs combinations, at multiple watershed scales, and to achieve targeted water quality objectives based on cost and effectiveness. This tool incorporates algorithms from the Storm Water Management Model (SWMM), the Hydrologic Simulation Program FORTRAN (HSPF) model and other BMP modeling techniques. In order to evaluate and validate the application of the SUSTAIN model in an agricultural scenario, a case study is developed for a midsize drainage area (307 ha) located in the Mississippi Delta. The agricultural watershed includes a surface drainage ditch in which three low grade weirs have been installed and monitored for water level and pollutants concentrations since July 2010. The objective of this study is to assess the performance and capability of the SUSTAIN model in the context of a real agricultural scenario where BMPs are implemented. The study also attempts to determine the cost-effectiveness curve for the implementation of BMPs in the study area (considering the number of weirs installed as a variable) using total suspended sediments and total phosphorus as control targets.<br /><a href="/pdf/2012_ortegaachury_pres.pdf">Download the presentation</a>
Low-Grade Weirs: An Innovative Best Management Practice for nitrate-N Mitigation
Year: Authors: Littlejohn K.A., Kröger R., Moore M.T., Farris J.L.
Best management practices (BMPs) generally refer to measures that provide some level of environmental protection for downstream aquatic systems. In agricultural watersheds, BMPs aim to improve the water quality of runoff from the landscape by controlling or trapping pollutants that can potentially degrade downstream aquatic ecosystems. Installation of low-grade weirs in agricultural drainage ditches is being evaluated as an innovative, yet cost effective, management practice that decreases nutrient concentrations and loads by increasing the water volume and hydraulic residence time of the ditch. The objective of our study was to assess the nutrient mitigation capabilities of low-grade weirs in artificially constructed ditches (four ditches with weirs and four without weirs). A replicated nutrient runoff event was simulated using a calculated 11-15 mg/L nitrate (NO<sub>3</sub>-) concentration applied continuously to each ditch for eight hours. Inflow and outflow concentrations and loads were quantified to determine overall NO<sub>3</sub>- reduction. A significant difference in weir and non-weir ditch volumes (<em>P</em>= 0.006) was observed, as well as a significant difference in observed hydraulic residence times between weir and non-weir ditches (<em>P</em>= 0.029). Similarly, ditches with weirs demonstrated a statistically lower (<em>P</em>= < 0.001) median outflow load (47.9 mg/min) than ditches without weirs (63.2 mg/min). An enhancement of the biogeochemical environment within the ditch was also observed, with a significantly greater NO<sub>3</sub>- concentration reduction (<em>P</em>= 0.029) during the hypothesized biogeochemical reduction phase of the experiment for those ditches containing weirs. These results highlight the dynamics of low-grade weirs in reducing nutrient concentrations and loads from agricultural landscapes, potentially establishing low-grade weirs as an additional, innovative BMP for nutrient reduction.
Analyzing the Hydraulics of a Biofiltration Swale Using HEC-RAS
Year: Authors: Bassi D., Rivas D., Diaz-Ramirez J., Martin J.
Hydraulic Engineering Center's River Analysis System (HEC-RAS) is a hydraulic model that was developed by the U.S. Army Corps of Engineers to execute 1-D hydraulic calculations. The software is made up of four 1-D river analysis tools that all use the same geometric data that is imputed by the user. It calculates steady flow water surface profile computations, unsteady flow simulation, movable boundary sediment transport computations, and water quality analysis. It comprises of a graphical user interface, data storage and management, and reporting functions. The purpose of this research was to use HEC-RAS to assess a biofiltration swale by calculating the flows, roughness, and sediment loads, as well as evaluating a porous check dam located at the end of the swale. The vegetative swale is a Best Management Practice (BMP) that is located on the South Farm at Mississippi State University. The 50-m long swale contains a rip-rap check dam at the downstream end of the BMP followed by a fiberglass flume. The watershed for the BMP contained cattle pastures and is approximately 8.4 ha. Since summer 2011, flows from storm events were measured using a Son-Tec Flow Meter in the field and water levels were used to measure the gage heights during the events. Rating curves (stage vs. discharge) were developed for the upstream, middle, and downstream (flume) sections of the BMP. Thirteen cross sections of the channel were found using a total station and the geometric data was imputed into HEC-RAS. Water samples were also collected during storm events using an automatic water sampler located at the entrance, middle, and flume sections, and the samples were analyzed in the laboratory for total suspended solids as well as various nutrients. Currently, we're setting up the model and planning to show model results at the conference.
Water Quality in Sardis Lake: A Multi-Variate Statistical Method for Analysis of Temporal and Spatial Trends
Year: Authors: Surbeck C.
Water quality data from rivers, lakes, and other bodies of water are collected by environmental agencies. These monitoring activities occur because of requirements set by regulations, and data are collected in a systematic way for the intended purpose. Monitoring enables agencies to determine whether water bodies are polluted. Much effort is spent for each monitoring event, resulting in hundreds of data points typically used solely for comparison with regulatory standards and then stored for little further use. This presentation shows a data analysis methodology applied to Sardis Lake in north Mississippi that uses a pre-existing dataset to extract more useful information on water quality trends, without new sample collection and analysis. In this presentation, measured lake water quality data are subjected to statistical analyses including Principal Component Analysis (PCA) to deduce changes in water quality spatially and temporally over several years. It was found that the lake water quality as a whole changed temporally by season, rather than spatially. Storm events caused the greatest shifts in water quality, and the shifts were fairly consistent across sampling stations. This methodology can be applied to similar datasets, especially with the recent emphasis by the U.S. EPA on protection of lakes as water sources. Water quality managers using these techniques may be able to lower their monitoring costs by eliminating redundant water quality parameters found in this statistical analysis.
Water quality and other ecosystem services from wetlands managed for waterfowl in Mississippi
Year: Authors: Kaminski R.M., Alford A.B.
A successful and increasingly applied conservation practice in the Lower Mississippi Alluvial Valley (MAV) to mitigate loss of wetland wildlife habitat and improve water quality has been development and management of "moist-soil wetlands." This conservation practice has the potential to provide ecosystem services critical to restoring wetland functions in the MAV such as reducing dispersal of sediments and nutrients into surrounding watersheds. Moreover, a significant potential exists for native crayfish (<em>Procambarus</em> spp.) harvest in moist-soil wetlands in the MAV. During spring 2011, we estimated average daily yield of crayfish from 18 moist-soil wetlands in Arkansas, Louisiana, Mississippi, and Missouri. Average daily yield in 2011 was 3.64 kg/ha (CV = 33%). This estimate was slightly greater and more variable than the estimated yield from Mississippi wetlands in 2009 (i.e., 1.75 kg ha<sup>-1</sup>; CV = 16%, n = 9) and wetlands in Arkansas, Louisiana, and Mississippi in 2010 (i.e., 2.18 kg ha<sup>-1</sup>;CV = 30%, n = 15) . Our estimated daily yield of naturally occurring crayfish from moist-soil wetlands is lower than 10 kg ha<sup>-1</sup> which is the average daily yield from commercially operated rice-crayfish ponds in Louisiana. However, our comparisons of operating budgets from the two harvest systems indicated that rice-crayfish systems incur $1455 in direct expenses per hectare whereas crayfish harvest operation in moist-soil wetlands incur $682 direct expenses per hectare. Although fixed expenses are lower in harvest operations from moist-soil wetlands, lower yields increased the break-even selling prices from $2.75 kg<sup>-1</sup> in rice-crayfish systems to $6.38 kg<sup>-1</sup> in moist-soil harvest systems. These prices, however, are still less than those observed in regions of the Southeastern United States outside of Louisiana. To determine if crayfish harvested from moist-soil wetlands are an acceptable seafood product relative to commercially harvested crayfish, we conducted a consumer acceptability panel in May 2011. We found that crayfish from both sources were well liked and did not differ significantly (p > 0.05) in overall consumer acceptability. In July 2010, we installed water quality monitoring stations at 5 wetlands and 5 agriculture fields. We monitored concentrations of nutrients and sediments exported from these habitats during storm events in December-March of 2010-2012. We determined that wetlands exported significantly less total suspended solids and NO<sub>3</sub> than agriculture fields in 2010-2011 whereas all parameters except for NH<sub>3</sub> were significantly lower in wetland effluent compared to agriculture fields in winter 2011-2012. We were able to calculate loads (kg ha<sup>-1</sup>) from wetland habitats during the study years and determined that total annual loads of nutrients were slightly greater than currently assumed loading values of wetlands in Mississippi (i.e., 1 kg ha<sup>-1</sup>). Quantifying these ancillary ecosystem services of moist-soil wetlands will encourage further establishment and management of these wetlands in the MAV and elsewhere for wildlife and associated environmental and human benefits.
Water-Conserving Irrigation Systems for Furrow & Flood Irrigated Crops in the Mississippi Delta
Year: Authors: Massey J.H.
The goal of this project was to improve irrigation water- and energy-use efficiency in one of the most economically important cropping rotations practiced in the Mississippi delta, the soybean-rice rotation. Combined economic activity for the two crops in the delta can approach $1 billion annually while combined irrigation water use is approximately 1 million A-ft per season. As a result, a modest reduction in the amount of irrigation water used in the soybean-rice rotation could help reduce the current overdraft of the alluvial aquifer. Results from these 2010-2012 on-farm trials indicate soybean irrigation savings using NRCS Phaucet optimization software averaged about 20% compared to non-optimized furrow irrigation while associated energy use reductions ranged from 32 to 20%, respectively. (It is important to note that in order to foster comparison, the soybean fields used in these studies were rectangular in shape; water savings are expected to be greater for more irregular (i.e., hard to irrigate) soybean fields.) Irrigation water used in rice grown using straight-levees with multiple inlets and intermittent flood management averaged 22.1 ± 2.4 A-in/A as compared to 32.4 A-in/A for straight-levee rice using multiple inlets without intermittent flood management. These results indicate that by overlaying an intermittent flood regime on practices that are already familiar to rice producers in Mississippi, rainfall capture is increased and over-pumping is decreased such that overall water use is reduced by ~40% over the standard rice irrigation practices. Field trials comparing rough rice yield and milling quality for up to 15 rice varieties indicated that commercial rice varieties, grown using standard fertility and pest control programs, well-tolerated a carefully-controlled intermittent flooding regime. Each inch of water not pumped from the Alluvial aquifer onto an acre of rice or soybean saves the energy equivalent of ~1 gallon diesel fuel with concomitant reduction in CO2 emissions by ~200 lbs/A. Assuming a current off-road diesel price of $3.20/gallon, a 9 acre-inch (40%) reduction in rice irrigation translates to a savings of ~$20 per acre while a 1.7 acre-inch (20%) reduction in soybean irrigation represents a savings of ~$3 per acre. By reducing irrigation water and associated energy inputs in soybean and rice production, the producer reduces input costs while reliving pressure on the Mississippi River Valley Alluvial aquifer and also reduces carbon emissions.
Predicting Nitrogen and Phosphorus Concentrations using Chlorophyll-a Fluorescence and Turbidity
Year: Authors: Andrews C., Kröger R., Miranda L.E.
Agricultural practices and land modification introduce excess nutrient and sediment loads into inland watersheds. Modification of tributary streams and rivers within these watersheds decreases the ability of floodplains to respond to increased loads. Therefore, large amounts of nutrients and sediments are transferred to coastal aquatic systems. Aquatic systems are facing increased nuisance algal growth and premature senescence leading to hypoxic conditions, threatening recreational and commercial fish yields. Furthermore, sedimentation and turbidity create intolerant conditions for aquatic organisms, and can trap phosphorus in these systems. To address these issues, states are developing nutrient criteria for inland waters. As inland water bodies are numerous, the usefulness of such criteria is dependent on efficient monitoring. We investigated the potential use of a handheld chlorophyll-<em>a</em> (chl-<em>a</em>) fluorometer as an estimator of total phosphorus (TP) and total nitrogen (TN) in oxbow lakes of the Mississippi Alluvial Valley. Several adjustments were explored to improve the ability of the fluorometer to accurately represent chl-<em>a</em>. Past studies in Mississippi lakes have shown a poor relationship between TP and chl-<em>a</em> (r<sup>2</sup> = 0.18), but a moderate relationship between TN and chl-a (r<sup>2</sup> = 0.53). The poor TP-chl-<em>a</em> relationship is partially attributable to naturally high levels of phosphorus and turbidity in the region. We found the relationships between chl-<em>a</em> and nutrient concentrations were improved in oxbow lakes; adding covariates such as turbidity and suspended solids further improved predictability. Estimating TP and TN with <em>in-situ</em> handheld-meter measurements of chl-<em>a</em> supplemented with measures of suspended solids may, in many cases, be adequate for temporal or spatial monitoring of nutrients in oxbow lakes.
Flooding Concerns on the Lower Pearl River Near Walkiah Bluff, MS
Year: Authors: Roberts A.L.
Walkiah Bluff is located in south Mississippi on the East Pearl River near Wilson Slough and the divergence of the Pearl River into the East and West Pearl Rivers. Approximately 175 residents own homes on or near the East Pearl River near Walkiah Bluff, MS. Flooding often occurs in the Walkiah Bluff area whenever flooding occurs upstream on the Pearl River, thus heightening concerns of local citizens. The Lower Mississippi River Forecast Center (LMRFC) has flood forecasting responsibility in this area, however, Walkiah Bluff is not currently a modeled site. <br /><br /> Historical data from the period of record was utilized to develop flood forecasting guidance tools for the Walkiah Bluff area. Flood events were analyzed to obtain a better understanding of how Walkiah Bluff reacts in relationship to upstream flooding on the Pearl River at Bogalusa, LA and the Bogue Chitto River at Bush, LA. Assessments were also made regarding how the Pearl River at Pearl River, LA reacts in association with upstream flooding at Walkiah Bluff and Bush. <br /><br /> The effects of the Bogue Chitto River on the crest at Walkiah Bluff, MS are complicated due to numerous sloughs and bayous that interconnect the two channels. It is difficult to accurately interpolate any affects from the Bogue Chitto by utilizing a crest to crest curve for Bogalusa to Walkiah Bluff. However, because the crest at Pearl River, LA is based upon water routed from both Bogalusa and Bush, the LMRFC forecast for Pearl River, LA can be utilized along with the crest to crest curve for Walkiah Bluff to Pearl River, LA to essentially back-forecast the crest at Walkiah Bluff. The results of this study are expected to assist in increasing the accuracy and timeliness of LMRFC flood forecasts for Walkiah Bluff citizens.
Flood Inundation Mapping for the Leaf River at the City of Hattiesburg, MS
Year: Authors: Storm J.
Flood forecasting predicts the eventual elevation of a river at a single location during moderate to extreme hydrologic events. Although this provides an understanding of the expected extremity of the flood, it does not give the general public an understanding of which areas will be affected and to what extent. The U.S. Geological Survey (USGS) Mississippi Water Science Center, in cooperation with the City of Hattiesburg, the Forrest County Emergency Management District, the Mississippi Emergency Management Agency, and the National Weather Service (NWS), is preparing a series of static flood inundation maps for the Leaf River at Hattiesburg, MS, based on a one-dimensional steady flow model calibrated to historic and current hydrologic data. The maps will be accessible to the public on USGS and NWS web pages and will provide flood depths and inundated areas at 1-foot increments of forecasted stage at the real-time USGS stream-gaging station 02473000 Leaf River at Hattiesburg, MS. These maps will provide both the public and city officials the ability for better planning and management during extreme flooding events.
Water-quality of the Yazoo River During the 2011 Mississippi River Flood
Year: Authors: Woods M.S., Rose C.E., Coupe R.H.
The Mississippi River was above flood stage at Vicksburg, Mississippi, for much of spring 2011. Water samples were collected during this period on a weekly basis from the Yazoo River near Vicksburg, Mississippi, and analyzed for nutrients, sediment, and pesticides as part of a U. S. Geological Survey study to assess water quality of the Mississippi River Basin. High water affected the water quality of the lower Yazoo River, as the Mississippi River stage rose and fell during the flood. Water-quality changes correspond not only to stagnant or reversed flows and accumulation and backwater effects, but also to different sources of water to the Yazoo River before, during, and after the flood. Before the spring 2011 flooding of the Mississippi River, the Yazoo River water came from two sources: the Delta and the Bluff Hills. Along the upper Yazoo River, flood-control structures at Steele Bayou and Little Sunflower Diversion Canal outlets were closed to prevent flooding in the Delta from the Mississippi River; during this time, the Yazoo River source is primarily from the Bluff Hills. During the flood, when the Mississippi River stage was higher than the Yazoo River stage, the Yazoo River flow was impeded and reversed, and mixing of the Mississippi River into the Yazoo River occurred. The Mississippi River was a major source of water to the Yazoo River near Vicksburg during flooding. For much of the 2011 growing season, the control structures along the Yazoo River were closed, thus causing sediment and nutrients to accumulate behind the flood control structures. As the Mississippi River receded following the flood, the flow control structures were reopened, flushing the stagnant and sediment-laden backwater into the Yazoo River, allowing the streams of the Delta to return to normal flow. Following the flood, the Yazoo River water source was primarily from the Delta. The changes in water-quality on the Yazoo River during the 2011 Mississippi River flood can be attributed to the different water sources caused by the flood.
Movement of Agricultural Chemicals and Sediment Through the Lower Mississippi River Basin During the 2011 Flood, April through July
Year: Authors: Welch H.L., Aulenbach B.T., Coupe R.H.
Extreme hydrologic events, such as floods, can overwhelm a surface water system's ability to process agricultural chemicals (nutrients and pesticides) and can move large amounts of sediment downstream to larger surface water bodies. The Mississippi-Atchafalaya River basin drains approximately 41% of the conterminous United States and is the largest contributor of nutrients to the hypoxic zone that develops along the inner continental shelf of the Gulf of Mexico each spring. From March through April 2011, the lower Mississippi River basin received more than five times more precipitation than normal, which combined with snow melt from the upper Mississippi River basin, created a historic flood event that lasted from April through July. The U.S. Geological Survey, as part of the National Stream Quality Accounting Network (NASQAN), collected samples from six sites located in the lower Mississippi-Atchafalaya River basin, as well as, samples from the three flow-diversion structures: the Birds Point-New Madrid in Missouri and the Morganza and Bonnet Carré in Louisiana, from April through July. Samples were analyzed for nutrients, pesticides, suspended sediments, and particle size; results were used to determine the water quality of the river during the 2011 flood. Monthly loads for nitrate, phosphorus, pesticides (atrazine, glyphosate, fluometuron, and metolachlor), and sediment were calculated to quantify the movement of agricultural chemicals and sediment into the Gulf of Mexico. Nutrient loads were compared to historic loads to assess the effect of the flood on the zone of hypoxia that formed in the Gulf of Mexico during the spring of 2011.
Develop Hydrological Relationships using a Modeling Approach in Mississippi Delta
Year: Authors: Jayakody P., Parajuli P.B., Sassenrath G.
Agriculture management practices such as tillage and crop rotations alter the hydrological budget of watersheds. Changes happen to surface runoff can be easily identify with the help of intensive USGS stream gage network, available in Mississippi, but changes to ground water table is less understood as inherent difficulties of measurements. The main objective of this research is to develop relationships among evapotranspiration (ET), soil moisture content (SMC) and depth to the ground water table through modelling approach. The SWAT hydrologic and crop models were setup for the Big Sunflower River watershed (BSRW; 7,660 km<sup>2</sup>) within Yazoo Rive Basin of the Mississippi Delta. Hydrologic calibration and validation was carried out for the period from 1999-2009 using USGS flow data. Crop model was calibrated and validated for the same period by using Corn and Soybean yield data from the USDA experiment stations. Both crop and hydrologic model performances will be evaluated using coefficient of determination (R<sup>2</sup>), Nash-Sutcliff Efficiency Index (NSE) and Root Mean Square Error (RMSE). Empirical relationships will be developed to predict depth to the groundwater table using model predicted ET and SMC. The relationships developed will be validated with the field observed data and will be used to make groundwater thematic maps for the Mississippi Delta.
Nitrogen dynamics within the Big Sunflower River Basin in northwestern Mississippi
Year: Authors: Barlow J.R., Coupe R.H., Kröger R.
Two important water issues in northwestern Mississippi are: (1) the export of nutrients to the Mississippi River and eventually to the Gulf of Mexico, and (2) the availability of water for irrigation and to sustain baseflow in streams. Recently, the Yazoo River Basin in Mississippi was identified as a significant contributor of total nitrogen and phosphorus to the Gulf of Mexico. The Big Sunflower River Basin, located within the Yazoo River Basin, receives large annual inputs of nitrogen from agriculture, atmospheric deposition, and point sources. Recent publications indicate that nitrate, once it enters the surface waters of the Big Sunflower River Basin, acts conservatively and does not undergo significant losses. Stream flow in the Big Sunflower River has been substantially altered by loss of base flow due to declining water levels in the underlying alluvial aquifer. Therefore, instead of being a predominantly gaining stream, the Big Sunflower River is now a predominantly losing stream allowing for surface-water to move through the streambed. Nitrate transported with surface water through the streambed, with its generally low oxygen environment, is susceptible to denitrification, thereby removing nitrate from the system. Over the past 2 years, the USGS, in cooperation with the USACE, has conducted a study to determine the relative roles of in-stream processing and groundwater/surface-water exchange on the transport and fate of nitrate in the Big Sunflower River. Preliminary results from this study indicate that the transport of nitrate in surface water moving through the streambed is removed by denitrification, whereas the in-stream transport of nitrate is relatively conservative.
Snapshot Through Time of "The Hole" in the MRVA of the Central Delta (Sunflower and Leflore County)
Year: Authors: Parish P.C.
The data utilized in this presentation will provide snapshots of the decline in water levels in what we affectionately call "The Hole". This will be done through the use of three dimensional maps, hydrographs, and geophysical logs. "The Hole" is an area of depression in the potentiometric surface of the MRVA (Mississippi River Valley Alluvial Aquifer). It is located in the central delta of northwest Mississippi. In large part it is centered in Sunflower and Leflore counties. The purpose of this research is to expand the examination of the growing trend of declining water levels in this area over time. This data collection involves drilling, historical research, and water level data collection. The water level measurements are mainly conducted in the Fall after irrigation season has ended and the Spring before irrigation season begins. <br /><br /> This examination leads us to the question, "Why?". There are many answers to that question which will be discussed in more depth. The geology in and around the delta both creates the possibility of such an aquifer as the MRVA, as well as, hinders its recharge and flow. Deforestation and dewatering of the land in the delta have also caused problems. Incision and dredging of channels in surface water bodies may contribute to the problem. Local domination of certain crops may contribute the trend. All of these areas need to be addressed and examined further.
The Great Flood of 2011 and its Influence on the Mississippi River Valley Alluvial Aquifer: Did the River Recharge the Aquifer or What?
Year: Authors: Byrd C.B.
The flooding along the Mississippi River during the months of April and May, 2011 was among the worst in the last 100 years. According to one source, this flooding event was comparable to the flooding that occurred in 1927 and 1993. Data from five gages that include stations at Memphis, Tennessee down to Vicksburg, Mississippi indicate that an all-time record was set at the gage at Vicksburg, Mississippi, and near-record stages were recorded at the other four stations. Seven states were impacted by the floodwaters, and for the first time in many years, the Morganza Spillway was opened to deliberately flood roughly 4,600 square miles of rural Louisiana so that New Orleans and Baton Rouge could be spared. <br /><br /> With all the record setting stages along the Mississippi River adjacent to Mississippi, one may ask, "What influence did the record-high river stages have on the Mississippi River valley alluvial aquifer (MRVA), which is the shallow aquifer in the alluvial plain (Delta) in the northwest portion of the state?" Unfortunately, the answer is not as straight forward as one may wish. <br /><br /> The Mississippi River is the western boundary for both the Delta and the alluvial aquifer. The depositional history of this river system is very complex, thus the geology of the alluvial aquifer is very complex. As the Mississippi River and its tributaries migrated throughout the alluvial plain, many stream channels were eventually cut off from the main river creating oxbow lakes. Through time, many of these oxbows were filled in with very fine-grained sediments, such as silt and clay. If the fine-grained sediments within an oxbow is of sufficient thickness, a "clay plug" is formed that serves to prevent any flow of water through it. Remnants of these old streams and oxbows are present all along length of the Mississippi River. However, if mostly fine- to coarse-grained sand and gravel was deposited, the river and the MRVA are most likely in very good hydrologic connection. <br /><br /> Water levels were collected during early May (the period of peak flooding) by the Office of Land and Water Resources staff. This data along with water level data collected by the Yazoo Mississippi Joint Water Management District staff during early April and early June were correlated with River stages. Then an analysis of geologic data was combined with the water levels and river stages to try to determine hydrogeologic connection.
The Mississippi Nutrient Management Manual: Simplifying Availability of Maintenance-Based Fertilizer Recommendations and Nutrient Best Management Prac
Year: Authors: Oldham L.
Plant nutrient dynamics at the agriculture and environment interface is a societal concern. Injudicious application rates or improper application may have deleterious effects on water or soil quality; however supplemental nutrient applications often maximize agronomic crop production and profitability. Prior to 2007, Mississippians spent about $155 million per year on fertilizers for all uses; dramatic price increases that year nearly doubled fertilizer expenditures. Fertilizer prices have been volatile due to both supply and demand issues since the adjustment. Broiler chicken production is the main animal feeding industry located in the state; the litter produced is valued as a plant nutrient source both in the poultry production region, and other areas in the state. Mississippi State University fertilizer recommendations are chiefly based on the maintenance philosophy of soil testing: providing sufficient phosphorus (P) and potassium (K) fertilizer for the current crop, and controlling soil acidity. The university does not recommend P and/or K if the soil test index is high or very high, except one research-verified exception for cotton. Nitrogen fertilizer recommendations are research-based crop and soil specific, but lack a valid soil test for Mississippi climatic conditions. For many years, specific crop recommendations resided in various outreach platforms, as did recommended Best Management Practices. With combined economic and environmental interests, there was a need to centralize the Mississippi State University Extension Service nutrient recommendation and associated Best Management Practice outreach efforts. The Nutrient Management Guidelines for Agronomic Crops Grown in Mississippi (Manual) was developed for ease of use by crop advisers, farmers, government advisers, and others. The Manual exists both as hard copy, and a dynamic, updatable presence on the Extension Service website. Chapters/subjects include introductions to Nutrient Management, soils of Mississippi, nutrients, soil testing, fertilizers, and lime. Other chapters focus on poultry litter as fertilizer and Best Management Practices for nutrients. Separate appendices include the soil testing based fertility recommendations for forages and annual agronomic crops. In addition, there is a Glossary of nutrient management terminology. The centralization of research-proven recommendations, information, and guidelines should facilitate better management of plant nutrients in the Mississippi environment for many years.<br /><a href="/pdf/2012_oldham_pres.pdf">Download the presentation</a>
Dating Sediments from Oxbow Lakes in the Mississippi Delta using <sup>239</sup>Pu, <sup>240</sup>Pu and <sup>210</sup>Pb determined by ICPMS: a feasib
Year: Authors: Cizdziel J., Chakravarty P.
Sediments are complex deposits of inorganic and organic matter that can serve as a natural storage system for metals and anthropogenic contaminants. Sediment cores can provide a window on the past because they can go back years, decades, even centuries and serve as environmental proxies. Dating of recent (<100 years) sediments is important in many studies and applications, including determining the source and timing of pollution events, establishing sedimentation patterns, and in reservoir management. Linking sediment "dates" (typically in years) with sediment characteristics or specific chemical constituents is also crucial for examining the effectiveness of both pollution and erosion control measures. Conventional dating techniques which use <sup>210</sup>Pb and <sup>137</sup>Cs are slow and costly, in part because extended times are needed to measure the radioactive decay emissions from low-activity samples. <br /><br /> In this study, we examined the feasibility of using inductively coupled plasma mass spectrometry (ICP-MS) to: measure global fallout plutonium (Pu) and <sup>210</sup>Pb in sediment core samples from Mississippi for dating purposes. Recent advances in mass spectrometry have made it an alternative to radioactive decay spectrometry for determining Pu, and possibly <sup>210</sup>Pb, in environmental samples. This study utilized core samples previously collected from strategic locations within the Mississippi Delta region. Select samples were be digested with mineral acids and the Pu and Pb isotopes were selectively removed from the matrix using chromatographic extraction resins, effectively pre-concentrating the elements prior to analysis. Plutonium was determined using isotope dilution mass spectrometry and <sup>210</sup>Pb using external standardization. In this talk and associated poster we will discuss the methodology and present our findings.
The National Reservoir Sedimentation Data Base: Background and Purpose
Year: Authors: Römkens M.J., Jones M.M., Gray J.
For many years, the Federal Interagency Subcommittee on Sedimentation (SOS), one of the nine Subcommittees of the USGS Advisory Committee on Water Information (ACWI), has been spearheading the development of a National Data Base concerning the sedimentation status of the Nation's Reservoirs. This data base is of critical importance for a number of issues such as water storage for flood control, sediment storage to reduce sediment movement in watersheds, water supply for irrigation and consumptive use, to maintain recreation functions, etc. Changes in the storage capacity may affect all these functions including the potential of the destabilization of the structures containing the reservoirs. The nation has more than 85000 dams and more than 110000 miles of levees. A large number of these dams are principally earthen dams that were built within the last 60 years, usually with an economic life time of 50 years. Many of them have lost a significant part of their storage capacity due to sedimentation. Decisions need to be made to decommission or rehabilitate these reservoirs and associated dam structures. The presentation will discuss the development of this data base, including the status of the reservoirs, dam failures and their disastrous consequences.
Sedimentation Processes in Perdido Bay
Year: Authors: Sigsby N.J., McAnally W.H., Sigsby N.
Perdido Bay is an estuarine system located along the Alabama-Florida border in the Gulf of Mexico with an estimated 2900 sq. km watershed and a narrow tidal inlet to the Gulf of Mexico. Water quality and hydrodynamics have been examined in some detail, but very little research has been done on the sedimentation processes of the bay. A systematic sedimentation study will contribute to an improved understanding of the processes of the bay. <br /><br /> An investigation into the sediment classifications, distributions, and discharges will be completed as a major part of this sedimentation study. As a first step, a data collection was performed in July 2011. This survey included water and bed sediment sampling, water quality readings, and velocity measurements. Water quality constituents tested included dissolved oxygen, pH, salinity, temperature, turbidity, and depth. Velocity and discharge calculations were recorded using an Acoustic Doppler Current Profiler. Bed sediment samples will be used for grain size analysis and sediment classification. The water samples collected will be used for total suspended solids analysis. Analysis of the tide levels, salinity and turbidity will be completed for the verification of the existence and location of the turbidity maxima in Perdido Bay. <br /><br /> A thorough literature review will be completed to better understand sedimentation processes, sediment budgets, numerical modeling, and historical data. Using this data, along with data collected on-site, a systematic sediment budget will be developed and a numerical model of sediment transport using EFDC will be developed.
Field-Scale Monitoring of Agricultural Ditches as Conduits of Nitrogen, Phosphorus, and Suspended Sediment in Response to Storm Events and Low-Input D
Year: Authors: Pierce S.C., Kröger R., Prevost D., Pierce T.
Runoff from row-crop agriculture is a major source of non-point source aquatic pollution. High concentrations of inorganic nitrogen and sediment-bound phosphorus that are conveyed in agricultural drainage ditches can lead to eutrophication of receiving waters at both local and regional scales. Concerns regarding accelerated eutrophication have led to a concerted effort toward understanding the movement of nutrients across the landscape and the management of agricultural drainages for water quality remediation. This study monitors field-scale movements of nitrate, nitrite, ammonium, dissolved phosphorus, particulate phosphorus and total suspended solids through agricultural ditches over several months preceding and following the implementation of controlled drainage practices including riser boards, slotted pipes, and low-grade weirs. Water samples were collected during baseflow conditions and storm events via grab sampling and different automated techniques. Pre-implementation data collected from January-July of 2011 is summarized below. Preliminary post-implementation data will be presented as it becomes available. Nitrate concentrations showed a high degree of variability both spatially and temporally, varying from approximately 0 to 15 ppm, with values higher in the watershed tending to be slightly higher than outflows. Storm events generally had nitrate concentrations 50% to 100% greater than baseflow concentrations. Nitrite also demonstrated temporal variation, with some samples approaching 1 ppm. Compared to nitrate, however, spatial differences and total variance was low. In contrast to oxidized nitrogen, ammonia concentrations generally ranged from 0.1 to 0.3 ppm regardless of time or location. Dissolved inorganic phosphorus concentrations ranged from approximately 0 to 1.5 ppm, varying nonlinearly with date the sample was collected, but did not appreciably change in response to storm events. Total inorganic phosphorus and turbidity approached an order of magnitude higher in stormwater samples than baseflow samples, with mean total inorganic phosphorus of less than 2 ppm in baseflow samples compared to mean values greater than 10 ppm in stormwater samples. Total suspended sediment concentrations were also significantly higher in stormwater samples than baseflow samples, indicating the likelihood that erosion or sediment resuspension is a major factor in phosphorus transport in agricultural drainage ditches. Preliminary data following implementation of controlled drainage will be compared with this background data set to determine short-term impacts of ditch reshaping on water quality and to estimate the effects of vegetation establishment.<br /><a href="/pdf/2012_pierce_pres.pdf">Download the presentation</a>
Nutrient and Suspended Sediment Mitigation Through the Use of a Vegetated Ditch System Fitted with Consecutive Low-Grade Weirs
Year: Authors: Flora C., Kröger R.
Mississippi is the largest producer of channel catfish (<em>Ictalurus punctatus</em>) in the United States. Channel catfish ponds cover over 20,000 hectares of land, mainly concentrated in the Alluvial Valley of northwest Mississippi. Water management practices to reduce mass discharge from ponds are currently a major point of concern, especially in light of potential regulations through nutrient criteria development. A vegetated ditch fitted with consecutive low-grade weirs is anticipated to be a practical and effective option of reducing nutrients and suspended solids entering downstream receiving systems. This study assesses the effect of low-grade weirs on chemical retention and settling of aquaculture pond effluent in a single drainage ditch. The efficiency of consecutive low-grade weirs will be compared in and across the system. The experiment was conducted September 26–October 1, 2011 at the aquaculture facilities at Mississippi State University. Three embankment ponds were discharged at 48 hour intervals into a single vegetated drainage ditch fitted with 4 low-grade weirs. Data will be analyzed to quantify the ability of the low-grade weir system to reduce the levels of ammonia, nitrate, nitrite, total inorganic phosphorus, particulate phosphorus, and dissolved inorganic phosphorus. The levels of total suspended solids and volatile suspended solids will be compared across the system. As water passes each weir the nutrient and suspended solid loads should decrease through the system, overall reducing the load entering the downstream receiving systems.<br /><a href="/pdf/2012_flora_pres.pdf">Download the presentation</a>
Runoff Quality Effects of Simulated Conservation Practice Scenarios in a Mississippi Delta's Watershed
Year: Authors: Ramirez-Avila J.J., Ortega-Achury S.L., McAnally W.H., Daiz J.N., Martin J.L.
The APEX (Agricultural Policy Environmental Extender) model was developed for use in whole farm and small watershed management with the capability of detailed field scale modeling and routing by connecting farm/field sized subareas. The ArcAPEX is an ArcGIS based user interface designed to automate the input parameterization of the APEX hydrologic/water quality model. The objective of this study is to evaluate runoff quality effects of alternative conservation practices scenarios for agricultural production in a northeastern Mississippi’s watershed using the APEX model and the ArcAPEX interface. Model evaluation compares the observed runoff sediment and nutrient losses from a USGS gauging station draining an 11 ha watershed in the Mississippi Delta with the simulated results generated by APEX. Initial stage of the study demonstrated a satisfactory capability of the model in simulating runoff and sediment at annual and monthly scales (R<sup>2</sup>≈0.8), but not at daily scale. Using no calibrated parameters, the model underestimated observed phosphorus loading. This maybe due to the use of the initial phosphorus concentration in soils set as zero. Modeling of conservation practice scenarios are expected to evidence an improvement of runoff quality condition at the edge of the studied watershed. Final results are also expected to compare APEX performance with other developed model(s) for the same location and scenarios.<br /><a href="/pdf/2012_ramirez_pres.pdf">Download the presentation</a>
Nutrient Characteristics of Moist-Soil Wetlands in Agriculture Landscapes
Year: Authors: Alford A.B., Kröger R., Kaminski R.M.
In the Mississippi Alluvial Valley (MAV), significant improvements in wetland management strategies have increased the availability of food for wintering waterfowl. Through seasonal drawdown and flooding schedules, moist-soil wetland management encourages growth of annual seed-producing grasses and sedges. Whereas the ecological importance of this conservation strategy is widely known, other environmental benefits, including its effect on water quality, are little understood. To quantify the nutrient exports from these wetlands and therefore explore their potential to improve downstream water quality in the MAV, we implemented a study to compare effluent water quality from runoff events from 5 spatially paired moist-soil wetlands and agriculture fields in Mississippi MAV during October 2010-March 2012. We measured concentrations (mg L<sup>-1</sup>) of nitrate, NO<sub>3</sub>-; nitrite, NO<sub>2</sub>-; ammonium, NH<sub>4</sub>+; total phosphorus, TP; total dissolved phosphorus, TDP; particulate phosphorus, PP and; total suspended solids, TSS. Mean concentrations of NO<sub>3</sub>- , TP, PP, and TSS were 91%, 37%, 49%, and 83% lower (<em>P</em><0.005) in effluent from wetlands than agricultural fields, respectively. Loads (kg) of nutrients discharged from wetlands will be calculated and used to evaluate how moist-soil wetlands in the LMAV aid in meeting Mississippi River and Gulf of Mexico nutrient reduction goals.<br /><a href="/pdf/2012_alford_pres.pdf">Download the presentation</a>
Management of Coastal Ecosystem Restoration Sites under Increased Climatic Extremes: Effects of Hurricane Katrina on Wetlands Restoration Projects in
Year: Authors: Foster M.A., Battaglia L.L.
Coastal wetland mitigation banks are at the forefront of climate change and are under strict regulatory requirements regarding plant community composition. As effects from climate change intensify, sea level rise and tropical storms may alter the composition of these communities. We measured aspects of plant community structure and diversity at a 382-hectare wetland mitigation bank in southwest Mississippi in 2005-20011. Rapid monitoring assessment with supplemental recording of all species detected was conducted each year at seven pine savanna monitoring plots. The site was in the eye-path of Hurricane Katrina and received over 2.5m of storm surge in August 2005. Multivariate analyses of the understory composition indicated that the high diversity, pre-Katrina community diverged after the storm to a lower diversity subset assemblage. Some recovery through time was evident, although species composition had neither stabilized nor returned to pre-storm conditions by 2011. Richness of savanna forbs dramatically declined following Katrina and has not yet recovered. The assemblages have continued to shift in composition since Katrina, but the eventual state of these systems is not yet known. The reference species composition for a mitigation site is typically strictly defined by regulatory requirements. As a result of tropical storm activity, these coastal ecosystems may be shifting away from fixed reference standards. The likelihood of a major vegetation state change increases as the effects of sea level rise and intensified tropical storm activity become more pronounced along the northern Gulf of Mexico.
Beneficial Use at Deer Island: A Decade of Design and Implementation
Year: Authors: Roth W.B., Mears W., Keith D., Ramseur G.
Deer Island, just offshore of Biloxi, Mississippi, provides habitat for native fish and bird species and wintering sites for migratory birds, and the nearshore area is utilized by recreational fishermen throughout the year.<br /><br /> In response to the continual shoreline land-loss at the island, a beneficial use (BU) site at Deer Island was completed in 2003 as a joint effort between the State of Mississippi Department of Marine Resources (MDMR) and the U.S. Army Corps of Engineers (USACE), Mobile District using dredged materials to restore some of the lost habitat. The BU site was designed to restore 52 acres of the island’s intertidal marsh and chenier using 400,000 cubic yards (CY) of dredged material. In 2005, Hurricane Katrina destroyed a significant portion of the restoration area; erosion of the interior marsh area has continued since that time.<br /><br /> Utilizing lessons learned from during and after the construction of the 2003 BU site at Deer Island, new design concepts were developed for the repair and expansion of the site. A containment berm will be constructed along the northern shoreline of the island. Approximately 350,000 CY of dredged material will initially be placed into the existing and new expansion BU areas. The material will be placed at numerous discharge locations within the containment areas to create variation in the finished elevation and to enhance habitat diversity. The western alignment of the containment and control berm will be left open to promote circulation and habitat formation as the dredged materials consolidate. The "open-ended" design will also allow for future expansion of the site.<br /><br /> With the implementation of Mississippi State Law § 49-27-6161, planners, engineers, and contractors participating in design efforts involving excavation of marine sediments in the State now have an obligation to integrate BU of dredged material as a placement option. Proposed BU locations, including Deer Island, along with the sediment testing guidance is presented in the Master Plan for the Beneficial Use of Dredged Material for Coastal Mississippi1 (the Master Plan). Developing and implementing the Master Plan provides a starting point for future maintenance and new work dredging projects in Mississippi, with a global goal to retain this valuable resource within the coastal estuarine environment.<br /><a href="/pdf/2012_roth_pres.pdf">Download the presentation</a>
Sea Level Rise Visualization and Measurements of Subsidence and Accretion Rates for the Alabama, Mississippi, and Florida Coastlines
Year: Authors: Wilson K.V.
Coastal communities throughout the U.S. are in the initial stages of planning and/or creating climate adaptation plans. Emergency managers, developers, and the general public have a need to understand the potential effect of a rising sea level, whether the land surface is subsiding or accreting, and how these phenomena may influence plans for developing future critical infrastructure and for habitat restoration and conservation.<br /><br /> The Alabama, Mississippi, and Florida Gulf of Mexico Coastal Internet Map Server (http://gom.usgs.gov/slr/index.html) was developed to provide an interactive online tool for the public to visualize the effects of sea level rise along coastal communities. This server was based an existing server which was built principally to display the maximum storm tide crest resulting from Hurricane Katrina (2005). This server quickly and easily projects 1-, 2-, 3-, 4-, 5-, and 6-ft sea level rises onto a 3-meter digital elevation model constructed from Light Detection and Ranging (LiDAR) data procured before Hurricane Katrina for Alabama and Mississippi and after Katrina for Florida from the Alabama line to the east side of the St. Marks National Wildlife Refuge, east of Apalachicola, Florida.<br /><br /> To determine rates of land surface subsidence or accretion due to sea level changes, surface Elevation Tables (SETs) were installed (and readings began) in late 2010 at six sites along the Mississippi and Alabama coasts. Each site has four SETs dispersed within the local area of the site. Three years of data will be collected to provide an estimate of the current rates of subsidence or accretion in the coastal marshes by comparing the leveling rates of vertical displacement to established National Geodetic Survey benchmarks.
Laymen, Experts, NGOs, and Institutions in Watershed Management
Year: Authors: Pappalardo G.
People's activities and behaviors are deeply related with water and ecosystems: the relationship between human communities, their places of life, and nature has always been a challenging issue, like Ian McHarg explains in 1969, inspiring many scholars' works. A question is open: who is part of human communities? <br /><br />It is possible to identify some groups of people: inhabitants, with their direct experiences of their native lands (laymen); researchers and practitioners, with scientific tools to understand and to design lands (experts); supporters of specific interests and hopes (NGOs); environmental authorities, with their responsibility in managing lands (institutions). They have different knowledge, roles, interests, and expectations and, according to Fisher, everybody should be allowed to participate into the decision-making process about environmental matters.<br /><br /> Elinor Ostrom also underlines the necessity of collaboration between different people and institutions to manage Common Goods, like rivers, rich soil, and hydraulic infrastructures.<br /><br /> Starting from this framework, this paper has an overall goal: to identify how do laymen, experts, NGOs, and institutions work together in managing their places of life. The main question is: how to establish a sort of deal among them, focused on watershed management, to experience collaborative practices able to affect every-day life styles toward a responsible use of resources and better water quality? Even if every context has its own peculiarities, it is useful to learn from different experiences. In Italy, these kinds of deal are experimental practices called River Agreements: they still are not so common, and in Sicily there is an ongoing process to define and to build a River Agreement for the Simeto Watershed. It is a Participatory Action Research (PAR) process, i.e. a deep collaboration between scholars and associations' activists to help local communities (Whyte), and I am directly involved in the process as researcher. So I am studying some Cases in the United States, focusing on Mississippi State, to give an input to the process. The Case Study Method is a useful tool for PAR processes, to help participants in visualizing possible alternatives (Francis). <br /><br />Through some Case Studies in Mississippi, chosen to answer the main question, this paper also will support the ongoing process in Sicily: it will be translated and shared with other participants through focus groups, public presentations and a web site under construction, as an opportunity for collective learning and education.<br /><a href="/pdf/2012_pappalardo_pres.pdf">Download the presentation</a>
Management Challenges for Deer Creek in the Mississippi Delta
Year: Authors: Killebrew R.
Rivers and central are paramount to surface water ecosystems. Many characteristics differentiate lake ecosystems from running water. Areas with flowing freshwater are called lotic (<em>lotus</em>, from <em>lavo</em>, to wash) and water moves along a slope in response to gravity. Lotic ecosystems are contrasted to lentic (<em>lenis</em>, to make calm) or lake ecosystems. Most lakes are open and have distinct flows into, through, and out of their basins. Throughflows, called <em>water renewal rates</em>, are often variable and slow in lakes but are continuous. <br /><br /> The distinction between running waters and lakes focuses on the relative residence times of the water. The importance of variable but continuous and rapid throughput of water and materials contained within is evident in the biology of most organisms living in running waters. When the energy of flowing water is dissipated, like it does in the transitional zone of reservoirs, the change to lentic characteristics is rapid. <br /><br /> How does one manage a water body that, for most of the year, is neither stream nor lake? Deer Creek in the Mississippi Delta is more like the Dead Sea in many respects. For much of the year it has no outflow and very little inflow. Deer Creek has a very small basin area because it is a perched water body. <br /><br /> This presentation will provide a glimpse into the many challenges of balancing the needs of the water body inhabitants with the needs or desires of the people who live along the water body.<br /><a href="/pdf/2012_killebrew_pres.pdf">Download the presentation</a>
Results of Regional SPARROW Models for Selected Watershed in Mississippi
Year: Authors: Rebich R.A.
SPARROW (SPAtially Referenced Regressions On Watershed attributes) models were developed by the U.S. Geological Survey to estimate nutrient inputs (total nitrogen and total phosphorus) to the northwestern part of the Gulf of Mexico from streams in the South-Central United States. These models included drainages in Mississippi: the Yazoo River Basin, the Big Black River Basin, and the South Independent Streams. The models were standardized to reflect nutrient sources and stream conditions during 2002. <br /><br /> Model results indicated that total nitrogen yields in the Yazoo River Basin generally were higher in the lower part of the Basin (an area locally referred to as the Delta) than in the upper part. Although total phosphorus yields generally were higher in the Delta than in the upper part of the Yazoo River Basin as well, yields also were high along the bluff hill area of the Basin prior to entry into the Delta area. The primary source of nitrogen and phosphorus in the Yazoo River Basin was fertilizer. Model results indicated that total nitrogen and total phosphorus yields in the Big Black River Basin were highest in the lower part of the Basin. Wet deposition of total inorganic nitrogen was the largest nitrogen source in the Big Black River Basin; for phosphorus, however, there were no dominant sources. Nitrogen yields generally were highest for areas adjacent to the Mississippi River levee and southern State boundary for the South Independent Streams Basin, whereas phosphorus yields generally were highest for areas adjacent to the Mississippi River levee. The primary source of nitrogen in the South Independent Streams Basin was wet deposition of total inorganic nitrogen; there were no dominant sources of phosphorus. <br /><br /> The SPARROW Decision Support System (DSS) is an online interactive tool created for these and other SPARROW models so that water managers, researchers, and the general public can have access to results for a variety of uses. Users can map loads, yields, concentrations, and sources by stream reach and catchment; track transport to downstream receiving waters, such as estuaries and reservoirs; evaluate management scenarios such as source reductions; and overlay other sources of information such as land use, states, counties, and hydrologic units. The SPARROW DSS is located at: http://cida.usgs.gov/sparrow/index.jsp .<br /><a href="/pdf/2012_rebich_pres.pdf">Download the presentation</a>
The Buttahatchie River Stabilization Project
Year: Authors: Maurer B.
The Buttahatchie River watershed is recognized by local and regional scientists, conservationists, and outdoors people for its ecological significance, especially the unique biological diversity found and documented in this system (Mississippi Museum of Natural Science, 2005). Mussel surveys, conducted by O'Neil et al (2004; 69 FR 40084), and the Mississippi Department of Wildlife Fisheries and Parks (2004) have documented viable communities of rare mussel species along several reaches of the Buttahatchie River and some of its major tributaries. In addition, rare and unique fish communities and species have been reported from the Buttahatchie River system (Mississippi Museum of Natural Science, 2005). In an unpublished survey (Hicks 2004) of 23 biological experts in Mississippi, the Buttahatchie River ranked second behind the Pascagoula River out of 14 rivers in Mississippi in terms of priority for conservation and ecological significance (Mississippi Museum of Natural Science, 2005).<br /><br />However, the lower reaches of the river have undergone wholesale channel adjustments in recent years, including widening, rapid erosion, quarry capture, and excess sediment. Erosion and excess sediment continue to be a problem in this area.<em> The Stability Analysis of the Buttahatchie River</em> by USDA National Sedimentation Laboratory (2005) cites disturbances including meander cutoffs, construction of the Tennessee-Tombigbee Waterway (including the impoundment of the Columbus pool), and gravel-mine capture.<br /><br />The Buttahatchie River Stabilization Project was completed by The Nature Conservancy and partners in October, 2010 , to demonstrate techniques to reduce non-point source (NPS) pollution within the Buttahatchie River Watershed, specifically NPS resulting from eroding river banks. The project was supported by a Section 319 Grant, and used several Best Management Practices (BMPs) designed to show habitat-oriented options to riverbank stabilization. Located in Lowndes County, Mississippi, the project met several important goals. Most immediately, it stabilized a rapidly eroding river bank and prevented thousands of cubic yards of soil from washing into the river. In the long term it is expected that the river bed in this area will also become more stable, and this will allow for improved habitat for fish, aquatic invertebrates, mussels, and other benthic organisms.<br /><br />It also created an open-air educational site that demonstrates several useful stabilization BMPs and sets of techniques. This unique setting allows for the comparison of various techniques in one location.<br /><br />The presentation will describe the individual BMPs, their installation process, and the resulting improvements to the river bank.<br /><a href="/pdf/2012_maurer_pres.pdf">Download the presentation</a>
Sources and Yield of Particulate Organic Carbon and Nitrogen In Managed Headwaters of Mississippi
Year: Authors: Hatten J., Dewey J., Mangum C., Choi B.
Managed, forested headwaters in Mississippi constitute a crucial part of watershed dynamics because they comprise more than 60-80% of stream networks and watershed land areas. Headwater streams contribute particulate forms of organic carbon (POC) and nutrients such as nitrogen (PON) to downstream fluvial environments. Flux of these materials from headwaters is difficult to quantify and few studies have examined their source. In particular, the relationships among origin and export of particulate organic carbon and nitrogen with stream discharge represent significant gaps in our understanding of headwater processes. POC and N serve vital function as a regulator of bacterial productivity, dissolved oxygen concentrations, nutrient cycling, and food web productivity however excess terrestrial input of POC and N can contribute to eutrophication and hypoxia in waters that are deficient in DO. This project augments current research efforts concerning hydrologic and hydrologically-mediated functions in managed, forested headwaters of Mississippi. This study quantifies the yield, source, and transport of POC and N within managed watersheds in order to better constrain the flux of OC, nutrients, and contaminants that bind to OM. Objectives are to (1) quantify exports of sediment, POC , and PON, (2) determine whether C and N are derived from a similar source using stable isotope ratios, and (3) determine whether additional process are occurring at a larger scale. Preliminary data linking suspended sediments to soils from 15 months of sampling across four management intensities will be presented. These data will be of value to forested-watershed managers in their efforts to weight the environmental cost vs. nutrient cycling benefit of organic inputs resulting from silvicultural activities.
Calculation of Water Surface Elevation Using HECRAS 4.1.0 for Fixing Tailwater Elevation for Powerhouse Site in Planned 37 MW Kabeli "A" Hy
Year: Authors: Pathak S.R.
Goal of this HECRAS 4.1.0 model analysis is to find out water surface elevations for safe and optimized layout of powerhouse located in left bank of Tamor river with other protective structures like floodwalls at different flood frequencies for planned 37 MW Kabeli "A" Hydroelectric Project. Powerhouse is costly and vulnerable component of any hydropower facility. Its safe location should be prioritized. Any increment in head is related with generation of extra revenue but powerhouse earthwork excavation volume incurs huge part of overall project cost initially. There is some sort of tradeoff between these two parameters to get an optimum design elevation. It is envisioned that 1-D US Army Corp’s HEC-RAS model can simulate flow conditions at different flood frequencies. This project is located in Panchthar and Taplejung districts in Eastern Development Region of Nepal. This project utilizes more than 15 km long loop of Kabeli River formed with Tamor River. Kabeli River, which is a tributary of Tamor river is diverted through a 4326.8 m long D-shaped headrace tunnel having internal finished diameter 5.65 m, discharging diverted water into Tamor River for power generation. The gross head of the project is 116.8 m and the design discharge based on 40 percentile flow set by government for power generation from flow duration curve (FDC) in river is 37.73 m<sup>3</sup>/s. <br /><br /> Kabeli River is one of the tributaries of Tamor River which itself is a major tributary of Sapta Koshi River basin.The catchment area above the proposed intake site of project is 864 km<sup>2</sup> and at powerhouse site is 3930 km<sup>2</sup> with elevation ranging from 452 m to 7200 m above mean sea level. In this catchment, monsoon pattern of climate is prevalent. It commences from June to September with heavy rainfall intensity for those four months compared to other months of the year. Rainfall intensity varies in catchment with elevation and runoff is calculated from different methods as powerhouse site is ungaged. <br /><br /> Due to global warming, glacial lake outburst flood (GLOF), known as mountain tsunamies in high Himalayas ( Kanchanjunga range) is highly probable. This zone lies in area with high seismic activity with possibility of GLOF, flooding populated areas and infrastructure downstream. Since glacial/snow hydrology study and data collection is still in nascent stage of development, analysis for design flood elevation has been done without taking into account those effects due to unavailability of data.<br /><a href="/pdf/2012_pathak_pres.pdf">Download the presentation</a>
The Fate and Transport of Glyphosate and AMPA into Surface Waters of Agricultural Watersheds
Year: Authors: Coupe R.H., Rose C.E., Welch H.L., Manning M.
Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops and is predominately used on soybeans, corn, potatoes, and cotton that have been genetically modified to be tolerant to glyphosate. Glyphosate is used extensively in almost all agricultural areas of the United States. The agricultural use of glyphosate has increased from less than 10,000 Mg in 1992 to more than 80,000 Mg in 2007. The greatest areal use is in the Midwest where glyphosate is applied on transgenic corn and soybeans. Yet the characterization of the transport of glyphosate on a watershed scale is lacking. Glyphosate and its degradate AMPA were frequently detected in the surface waters of 4 agricultural watersheds. The load as a percent of use ranged from 0.009 to 0.86 percent and could be related to 3 factors: source strength, hydrology, and flowpath. Glyphosate use in a watershed results in some occurrence in surface water at the part per billion level, however, those watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff, and a flowpath that does not include transport through the soil.<br /><a href="/pdf/2012_coupe_pres.pdf">Download the presentation</a>
A Holistic Assessment of the Occurrence of Metolachlor and 2 of its Degradates Across Various Environmental Compartments in 7 Environmental Settings
Year: Authors: Rose C.E., Welch H.L., Coupe R.H., Capel P.D.
The widely used herbicide, metolachlor, is one of the most frequently detected pesticides in surface water and groundwater throughout the United States in both agricultural and urban settings. Metolachlor has also been detected in rain and in the unsaturated zone. The U.S. Geological Survey conducted a study to assess the controlling factors in the transport and fate of metolachlor and its degradates across seven watersheds in California, Indiana, Iowa, Maryland, Mississippi, Nebraska, and Washington during 1997-2007. The occurrence of metolachlor and two degradates (metolachlor ethane-sulfonic acid and metolachlor oxanilic acid) was examined in several environmental compartments within these environmental settings; groundwater, surface water, overland flow, subsurface drains, the unsaturated zone, and the atmosphere. Within these environmental compartments, the occurrence of metolachlor and its degradates primarily is affected by a number of factors including use, management, environmental setting, and physical and chemical properties of metolachlor and its degradates. The fate of metolachlor can be generalized by the environmental compartments. The majority (90%) of metolachlor is taken up by plants, degraded in the soil, or is trapped in/adsorbed to soil. About 10% of the applied metolachlor is volatilized into the atmosphere, and about 0.3% returns by rainfall. Some (0.4%) metolachlor is transported to surface water, while an equal amount (0.4%) is infiltrated into the unsaturated zone and may move downward into groundwater. Generally, groundwater stores less than 0.02% and does not serve as a metolachlor source to receiving surface waters.<br /><a href="/pdf/2012_rose_pres.pdf">Download the presentation</a>
Developing rapid methods for dating sediments in Mississippi using ICPMS
Year: Authors: Cizdziel J.
Sediment cores from seasonal wetland and open water areas from Oxbow lakes [Beasley (BL), Hampton (HL), Washington (WL), Roundaway (RL), Sky (SL) and Wolf (WL)] in the Mississippi Delta, whose chronology was previously determined by conventional <sup>210</sup>Pb and <sup>137</sup>Cs age-dating, were analyzed, for the first time, for Pu isotopes (<sup>239</sup>Pu and <sup>240</sup>Pu), and Pb isotopes (<sup>206</sup>Pb, <sup>207</sup>Pb, <sup>208</sup>Pb and <sup>210</sup>Pb). The primarily purpose was to evaluate the feasibility of using ICPMS as an alternative to radiochemical analyses for fallout-Pu and <sup>210</sup>Pb. <br /><br /> For Pu, the mean <sup>240</sup>Pu/(<sup>239</sup>Pu atom ratio was ~0.177 indicating global fallout as the primary and likely source of the Pu. Analyses of an undisturbed sediment core yielded a Pu peak at a depth which is in good agreement with conventional <sup>137</sup>Cs and <sup>210</sup>Pb dating. Analysis of the Washington Lake sediment core yielded a Pu vs. depth profile that was broad and uncharacteristic of normal sedimentation patterns. It was later found out that the conventional dating technique also yielded data scatter indicative of sediment that was likely disturbed <em>in-situ</em>. Indeed, because sediment can be mixed by natural events after deposition, this demonstrates that ICPMS can serve as a useful tool to simultaneously identify (screen for) sediments that have been disturbed (eliminating costly <sup>210</sup>Pb analyses on such cores), and to provide a chronological marker for those that haven't (either alone or in conjunction with conventional dating). <br /><br /> For Pb, total concentrations varied from 1.5 ppm to 12 ppm, with peak levels generally occurring during the 1950's. Isotopic signature plots suggest "natural" Pb (from soil) as the primary source of the lead, with coal and gasoline as slight contributors; however, more study is needed to confirm this. Accurately measuring the <sup>210</sup>Pb isotope by ICPMS was problematic. The levels were low and subject to interference from stable isotopes of Pb, possibly by the tail of the large <sup>208</sup>Pb peak and/or from polyatomic interference such as <sup>208</sup>Pb<sup>1</sup>H<sup>1</sup>H. To overcome these barriers, it is recommended to boost the sensitivity, possibly with a jet-face interface, and/or remove the interference using collision cell technology.
Rainfall Simulation to Evaluate Nutrient Loss from Marietta Soil Amended with Poultry and Cattle Manure
Year: Authors: Read J.J., McLaughlin M.R., Adeli A.
The main waste product produced by the broiler chicken industry is litter (manure and bedding materials), which is typically used as N-P-K fertilizer for pasture and hay crops on the producing farm or nearby farms. Studies in Mississippi indicate the average annual addition of nutrients is approximately 289 kg ha<sup>-1</sup> N, 150 kg ha<sup>-1</sup> P<sub>2</sub>O<sub>5</sub>, and 299 kg ha<sup>-1</sup> K<sub>2</sub>O, assuming all the litter was applied on the ‘average’ 54-ha farm without allowance for buildings, roads, water bodies, or forests. Of the total land area, approximately 474,000 ha is utilized for grazing by livestock, which constitutes another source of manure nutrients. The build up of N and P at the soil surface (0-15 cm) increases the potential for degradation of surface and groundwater resources, but the ultimate fate of much of the manure N and P is not known. This paper presents results of a rainfall-simulation study conducted in the greenhouse using eight, 8-cm deep PVC troughs (0.20 m wide x 1.45 m long) that contained sod of common bermudagrass collected from a Marietta loam soil. The objective was to determine if the combination of cattle feces (dung) and broiler litter increased the potential nutrient load in the surface-water runoff, as compared to broiler litter only. The treatments comprised 130 g litter (~3500 mg N) to six troughs, 24 g dung (~144 mg N) to four of these six; and two un-amended controls. The quantity and quality of soil leachate was determined after five "events" at a rainfall intensity of 75 mm h<sup>-1</sup>. Results indicated total N loads of 64, 366, and 378 milligrams in the control, broiler litter and litter + dung treatments, respectively, which renders a N-leaching loss of approximately 10% for Marietta soil under these conditions. The majority of leachate N, 40 to 70% across manure-amended troughs, was recovered in the first rainfall event. In general, NH<sub>4</sub> was the predominant inorganic constituent recovered in leachate. The quantity of leachate N was similar in the litter and litter + dung treatments, suggesting cattle grazing is not expected to contribute significantly to the N loss in runoff from pasture fertilized with 4.48 Mg broiler litter ha<sup>-1</sup>. Results will be discussed in relation to managing bermudagrass, broiler litter and grazing to decrease watershed runoff losses of N and P.
Proposal of the Total Human Ecosystem on Blakeley Island, Mobile AL
Year: Authors: Zhou L.
The principle of industrial ecology and landscape ecology has been touched upon in the past decades by scientists, ecologists and landscape architects. The concepts of industrial ecology have passed beyond the idea of controlling pollution and are trying to foster "thinking like an ecosystem". Landscape ecology focuses on the spatial pattern intertwined with processes and changes. Through applying the model of "Total Human Ecosystem" with the structure of patch-corridor-matrix, landscape ecology provides a model applied to the environment with human disturbance. Mobile, AL is a city built in wetlands and it was dominated by heavy industry. Blakeley Island is one of the largest industrial areas in Mobile, AL. The situation in Blakeley Island reflects the paradox at a global scale. On one hand, people are searching for more methods to take full advantage of the environment and create jobs. On the other hand, people complain about the degradation of their living habitats due to the overdevelopment. This paper focuses on how to create an ecological and sustainable living system that provides reconciliation between the industrial park and natural wetlands on Blakeley Island. My research explores the application of the Total Human Ecosystem model through landscape transition at urban scale in a way that, natural processes and industrial processes cooperate. Besides science, for example landscape ecology, has provided knowledge about the role of human in creating and affecting patterns and processes. But science has been less effective in transforming this knowledge to society and design is a common ground for scientists and practitioners to bring scientific knowledge into decision-making. The novelty of my method is the integration of science and design from dysfunctional patch recovery and corridors creation, to the new cybernetic symbiosis cycle formulation.
Formaldehyde Released in Leachate from Medium Density Fiberboard (MDF) Buried in a Simulated Landfill
Year: Authors: Lee M., Prewitt M.L., Borazjani H., Mun S.P.
Formaldehyde, a flammable, colorless, highly reactive gas at standard temperature and pressure, is commonly found in the environment. However, formaldehyde is toxic in high concentrations and causes health issues for human. Approximately 14 million tons of wood waste containing formaldehyde based resins are generated yearly and disposed in large pits and landfills or burned. No regulations however exist for formaldehyde emission from formaldehyde bonded wood waste buried in landfills. More information is needed about the environmental impact of formaldehyde released in water from formaldehyde bonded wood waste buried in landfills. The objectives of this study were to determine a) the amount of formaldehyde released, b) the amount of dissolved oxygen, and c) the microbial enumerations in leachate from MDF buried in a simulated landfill using two board sizes. Simulated landfills were constructed in cylindrical plastic containers (15.24 cm diameter, 22.86 cm high) with alternating layers of 2.54 cm silty clay soil and MDF for a total of five layers. Leachate was sampled on day 0, 7, 14, 21 and 28 for formaldehyde analysis and dissolved oxygen and microbial enumeration were conducted only at the beginning and end of the study. Formaldehyde released in leachate was determined by derivatizing using pentafluorbenzylhydroxylamine and analyzing by gas chromatography with electron capture detection. Preliminary results indicate that formaldehyde released in the leachate was reduced by 99% at the end of the study. The initial pH of the leachate from soil without MDF was 5.87 and increased to 6.18 at the first week's sampling time and remained at approximately 6.22 through week five, while the leachate from soil with added MDF had an initial pH of 4.66 and increased weekly to 6.40 on week 5. Results from this study should provide new information about the fate of wood waste containing formaldehyde disposed in landfills.
Assessing a Novel Method for Verifying Automated Oxidation-Reduction Potential Data Loggers: Laboratory and Field Tests
Year: Authors: Shoemaker C.M., Kröger R., Pierce S.
Redox potential (Eh) describes the electrical pressure of systems. In waterlogged soils, Eh is an important parameter for regulating the products of biogeochemical cycling. Until recently, Eh was measured at individual points using an electrode attached to a voltmeter. This method can overlook dynamic diel and short term fluxes in the environment. Automated data loggers enable long-term continuous monitoring of Eh in soils; however, no protocol has been developed for testing the accuracy and precision of these loggers. Automated data loggers were tested under a laboratory with known voltages to assess the ability of these units to record Eh precisely and accurately. Voltages of +450 and -450 mV were applied to four loggers with four Eh sensors five times at +450 and -450 mV for each sensor, totaling 40 tests for each board. The average measured voltages varied from each other a maximum of ±8.25 mV and with a maximum range of ±23 mV. The voltage averages of all boards were accurate to ±17.85 mV with a maximum range of ±26 mV. These results indicate that measurements obtained by automated data loggers can be accurate to within a maximum of ±26 mV of the true value. Since soil Eh has a range of over 1000 mV, continuous automated data loggers can be a powerful tool in describing Eh fluxes in waterlogged systems. Additionally, field data obtained from the automated data loggers placed in vegetated and non-vegetated control plots were able to record vegetative diel Eh fluxes over a period of 48 hours. Significant spatial heterogeneity and vegetative influences were observed in Eh values. The loggers thus have the possibility to be used to monitor Eh responses to various management practices and environmental factors.<br /><a href="/pdf/2012_shoemaker_pres.pdf">Download the presentation</a>
Using Dissolved Oxygen Dynamics to Derive Nutrient Criteria: Tried, True, and Troublesome
Year: Authors: Hicks M.B., Paul M.J., Caviness K.
Linking nutrient enrichment to adverse ecological effects involves a series of potential causal pathways and proximal stressors. A common proximal stressor is alteration of dissolved oxygen dynamics due to enriched organic matter loading and decomposition. Predictions associated with nutrient enrichment include both the potential for reduced minimum oxygen concentrations, as well as, increased maximum dissolved oxygen and diel fluctuation. Several states have expressed interest in and used oxygen range as a potential response metric. The U.S. Geological Survey sampled more than 50 low gradient Mississippi streams for the period 2009 to present and analyzed samples for dissolved oxygen and nutrients. Several oxygen characteristics were calculated (min, max, range, mean, sd) and related to concurrent nutrient, chlorophyll, and invertebrate assemblage data. All measures of oxygen showed some relation to nutrient concentrations; however, minimum and central tendency measures were most strongly related. At the same time, invertebrate metrics showed a stronger response to minimum concentration among all other measures.<br /><a href="/pdf/2012_hicks8_pres.pdf">Download the presentation</a>
Downstream Water Quality and Quantity Impacts Of Water Storage Systems in a Mississippi Delta Watershed
Year: Authors: Tagert M.L., Paz P., Pote J., Kirmeyer R.L.
The Mississippi River Basin contains over 60% of the United States' harvested cropland, and the Mississippi and Atchafalaya Rivers contribute more than three-fourths of the total nutrient load to the Gulf. Since the 1970's, groundwater levels in the Mississippi Alluvial Aquifer have decreased at a rate of approximately 100,000 acre-feet per year due to increased irrigated acres. There are roughly 13,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer. Adequate supply of good quality water is vital to sustaining agriculture, the primary industry in the economically depressed Mississippi Delta. Due to concerns over groundwater declines and increasing fuel costs to run irrigation pumps, farmers have begun implementing irrigation conservation measures, such as creating on site storage areas to capture irrigation and surface water runoff from the field for later use. However, while decreases in groundwater levels have been of particular concern to agricultural producers withdrawing from the Mississippi Alluvial Aquifer in recent years, there has also been a push by federal agencies to reduce the Gulf of Mexico hypoxic zone. The Mississippi River/Gulf of Mexico Nutrient Management Task Force, formed in 1997, set a goal to reduce the size of the Gulf hypoxic zone to less than 5,000 km<sup>2</sup> by the year 2015. In 2010, the Natural Resources Conservation Service launched the Mississippi River Basin Healthy Watersheds Initiative to support the implementation of conservation practices to reduce nutrient loading in the Basin and improve water quality in the Basin and Gulf of Mexico. This presentation will outline a USDA-funded project that will determine the watershed-scale impacts of water storage systems on water quality and quantity, using the example of Porter Bayou Watershed, Mississippi.<br /><a href="/pdf/2012_tagert_pres.pdf">Download the presentation</a>
MIST: A Web-Based Irrigation Scheduling Tool for Mississippi Crop Production
Year: Authors: Rice M.B., Crumpton J., Schmidt A., Sassenrath G., Schneider J.
Increased reliance on supplemental irrigation has begun to deplete the alluvial aquifer in the Mississippi Delta region. To alleviate nonproductive overuse of groundwater resources, we are developing a web-based irrigation scheduling tool. The Mississippi Irrigation Scheduling Tool (MIST) uses a water balance approach, calculating evapotranspiration from weather data using standard ET equations. User input is streamlined by relying on automatic integration of soils data and weather information from national databases. MIST is currently being tested in various production management scenarios for corn and soybeans and for different alluvial soils common to the Mississippi Delta. The web interface allows users to input the necessary data that is required to compute the aforementioned formulas. Users then will be able to access the irrigation scheduling information remotely. Using java, jsps, and a SQL database, the web interface attempts to be easy to use for all users. The data that must be entered by a user should be data that is common or easily accessible knowledge to a farmer. Google Maps provides a framework to display and select the features (maps, fields, and wells) via the Internet, minimizing computation resources needed by users. Following completion of testing and validation, the research team is planning a tentative general release for the 2013 growing season.<br /><a href="/pdf/2012_rice_pres.pdf">Download the presentation</a>
Coles Creek Watershed Assessment and Education
Year: Authors: Silitonga M., Johnson A.
The Coles Creek Watershed, located in the southwestern quadrant of the state of Mississippi, is listed under the US EPA impaired water section 303(d). Degradation of the ponds/lakes and streams/creeks in this watershed is caused mostly by biological impairment, followed by nutrients, organic enrichment or Low Dissolved Oxygen, sediment/siltation, pesticides, and pathogens (US EPA, 2007). These impairments cause the degradation of water quality thus causing euthrophication or algal bloom that can lead to fish kills and can also adversely affect human health. The causes of algal blooms have not been studied; therefore, data is needed to evaluate the quality of water and soil in the surrounding areas of the watershed. The data obtained will be used to analyze and determine the situation and find effective methods to solve the problem. Community participation in the area is much needed to improve, maintain, and restore the quality of water. Thus, educational materials are necessary to engage the community in protecting the quality of water in this area.<br /><br />Each water body is unique depending upon its geological characteristics such as natural landscape features and human activities related different land uses and landmanagement practices. In the Coles Creek Watershed, several identified water bodies have been heavily impaired.<br /><br />Poor water quality can harm fish, wildlife, and their habitats. Many things are known to cause poor water quality including: sedimentation, runoff, erosion, dissolved oxygen, pH, temperature, decayed organic materials, pesticides, and toxic and hazardous substances. Therefore, identifying the cause of degradation and finding the best management practice(s) (BMPs) as well as protection strategies have to be developed for each lake, pond, or river, individually.<br /><br />The purpose of the study is to investigate, assess, and find solutions to improve the quality of surface water bodies that can be adopted and implemented in the watershed.
Influences of Land Surface/Land Use Characteristics on Precipitation Patterns Over the Lower Mississippi Alluvial Plain
Year: Authors: Dyer J.
The lower Mississippi River alluvial valley in southeast Arkansas, northeast Louisiana, and northwest Mississippi is characterized by widespread agriculture with few urban areas. Land use is predominantly cultivated cropland with minimal topographic variation; however, the eastern edge of the alluvial valley is defined by a rapid, though small, change in elevation into a heavily forested landscape. This change in land use / land cover has been shown to potentially enhance precipitation through generation of a weak mesoscale convective boundary. This project defines the causes and influence of the land surface on associated precipitation processes by simulating a convective rainfall event that was influenced by regional surface features. Analysis was conducted using a high-resolution simulated dataset generated by the Weather Research and Forecasting (WRF) model. Results show that the strongest uplift coincides with an abrupt low-level thermal boundary, developed primarily by a rapid change from sensible to latent heat flux relative to the agricultural and forested areas, respectively. Additionally, surface heating over the cultivated landscape appears to destabilize the boundary layer, with precipitation occurring as air is advected across the land cover boundary and the associated thermal gradient. This information can be used to define and predict surface-influenced convective precipitation along agricultural boundaries in other regions where the synoptic environment is weak.
A climate-driven model to serve as a predictive tool for management of l groundwater use from the Mississippi Delta shallow alluvial aquifer
Year: Authors: Wax C.L., Pote J.
The objective of this research was to develop a model that can be used as a management tool to find ways to meet the needs for water use while conserving groundwater. This is the third phase of the project to meet these objectives. In phase one of the project, the growing season precipitation was used to develop a relationship that estimated irrigation use, and this was the driving mechanism of the model that simulated water use to the year 2056. Phase two added the use of surface water when growing season precipitation was 30% or more above normal. In this third phase, a new climatological input was introduced into the model—irrigation demand. Irrigation demand was calculated using daily precipitation, evaporation, and a crop coefficient to estimate daily water needs by crop type. Daily values were summed to one week segments which were added to derive the total growing season irrigation demand. Weekly summations increased temporal resolution, improving model efficiency in accounting for excess daily rainfall, allowing the model to apply excess rainfall in subsequent days.
Water-Conserving Irrigation Systems for Furrow & Flood Irrigated Crops in the Mississippi Delta
Year: Authors: Massey J.H.
The goal of this project was to improve irrigation water- and energy-use efficiency for one of the most economically important cropping rotations practiced in the Mississippi delta, the soybean-rice rotation. Combined economic activity for the two crops in the delta exceeds $600 million annually while combined irrigation water use approaches 2 million A-ft per season. As a result, a modest reduction in the amount of irrigation water used in the soybean-rice rotation could help reduce the current overdraft of the alluvial aquifer. Results from these 2010 on-farm trials indicate soybean irrigation savings using NRCS Phaucet optimization software ranged from 6 to 18% compared to non-optimized furrow irrigation while associated energy use reductions ranged from 32 to 20%, respectively. (It is important to note that in order to foster comparison, the soybean fields used in these studies were rectangular in shape; water savings are expected to be greater for more irregular (i.e., hard to irrigate) soybean fields.) Irrigation water used in rice grown using straight-levees with multiple inlets and intermittent flood management averaged 23.1 ± 2.4 A-in/A as compared to 32.4 A-in/A for straight-levee rice using multiple inlets without intermittent flood management. These results indicate that by overlaying an intermittent flood regime on practices that are already familiar to rice producers in Mississippi, rainfall capture is increased and over-pumping is decreased such that overall water use is reduced by ~40% over the standard rice irrigation practices. Field trials comparing rough rice yield and milling quality for 15 rice varieties grown on two soil series indicated that commercial rice varieties, grown using standard fertility and pest control programs, well-tolerated a carefully-controlled intermittent flooding regime. Each inch of water not pumped from the Alluvial aquifer onto an acre of rice or soybean saves the energy equivalent of ~0.7 gallon diesel fuel (with concomitant reduction in CO2 emissions by ~200 lbs/A). Assuming a current off-road diesel price of $3.20/gallon, a 9 acre-inch (40%) reduction in rice irrigation translates to a savings of ~$20 per acre while a 1.5 acre-inch (18%) reduction in soybean irrigation represents a savings of ~$3 per acre. By reducing irrigation water and associated energy inputs in soybean and rice production, the producer reduces input costs while reliving pressure on the Alluvial aquifer and also reduces carbon emissions.
Sources, sinks, and yield of organic constituents in managed headwaters of the Upper Gulf Coastal Plain of Mississippi
Year: Authors: Hatten J.A., Dewey J.C., Ezell A.W.
Sediment, organic matter, and nutrients (particularly nitrogen) are the constituents that most often lead to the impaired designation for rivers in Mississippi (E.P.A. 2000). Headwater streams are very important contributors of water, sediment and nutrients to the downstream fluvial environment. Many studies of non-mountainous systems have focused on the quantity of particulate or dissolved forms of material (e.g. suspended solids, organic matter, and nitrogen); few have examined the source of this material. The relationships among origin, storage, consumption and export of organic matter (OM) with stream discharge and subsurface interflow represent significant gaps in our understanding of headwater processes. This study is part of a larger-scale study investigating the effects of silvicultural best management practices in ephemeral and intermittent drains on hydrologic function in small-scale headwaters. A 30 ha watershed located approximately 8 miles west of Eupora in Webster County, MS has been continuously monitored for water table elevation, precipitation intensity and duration, in-stream TSS, and chemical composition of water and particulates. Data were used to elucidate the transport and source/sink behavior of sediment, and dissolved and particulate forms of organic matter, in the form of nitrogen (N) and organic carbon (OC), over a broad range of hydrographic conditions. Results indicate that particulates in perennial and ephemeral-intermittent stream segments are derived from surface mineral soil horizons as a result of downcutting. The source of water in the perennial stream is dominated by ephemeral stream contributions rather than groundwater during dry periods. During the wet winter months perennial streamwater chemically resembles groundwater whereas ephemeral-perennial segments chemically resemble canopy throughfall waters. Ephemeral drains are significant contributors to downstream perennial streams, especially during dry periods; therefore it is important to consider ephemeral basins within an overall basin management plan.
Ecosystem Services from Moist-Soil Wetland Management
Year: Authors: Spencer A.B., Kaminski R.M., D'Abramo L.R., Avery J.L., Kroger R.
Moist-soil wetlands in the Mississippi Alluvial Valley (MAV) are dewatered in spring through summer to promote production of grasses, sedges, and other herbaceous vegetation which are prolific producers of seeds and tubers for migrating and wintering waterfowl. Moist-soil wetlands are also potential sites for production and harvest of native crayfish (<em>Procambarus</em> spp.). Harvests of crayfish for human consumption in the United States amounts to $115 million annually. In springs 2009 and 2010, we harvested crayfish from moist-soil wetlands in Arkansas, Louisiana, and Mississippi. We harvested 92.2 kg of crayfish over 1,298 net nights in 2009 and 94.3 kg over 2,005 net nights in 2010. Mean daily harvest of crayfish from moist-soil wetlands was 1.75 kg/ha (CV = 16%, n = 9) in 2009, 1.25 kg/ha (CV = 17%, n = 13) in 2010, and 1.56 (CV = 13%, n = 22) for years combined. Whereas these yields are lower than reported for Louisiana cultured crayfish (i.e., 10 kg/ha), the economic value of native crayfish harvested from moist-soil wetlands may be significant to landowners considering the practice neither requires planting a forage crop for crayfish nor their capture and transport to rice fields. Additionally, within the MAV, strategic location of moist-soil wetlands amid farmed landscapes can reduce dispersal of sediments and other nutrients into surrounding watersheds. In July 2010, we installed water quality monitoring stations at six moist-soil wetlands and six adjacent agriculture fields in the Mississippi portion of the MAV. We will present preliminary estimates and comparisons of concentrations (mg L<sup>-1</sup>) and loads (kg) of nitrate, NO<sub>3-</sub>-N; nitrite, NO<sub>2-</sub>-N; ammonium, NH4+-N; total phosphorus, TP; total dissolved phosphorus, TDP; particulate phosphorus, PP and; total suspended solids, TSS exported from moist-soil wetlands and agriculture fields. Quantifying these ancillary ecosystem services of moist-soil wetlands will encourage further establishment and management of these wetlands in the MAV and elsewhere for wildlife and associated environmental benefits.
Assessing Early Responses of Natural Coastal Systems to Oil and Dispersant Contamination along the Northern Gulf of Mexico
Year: Authors: Ervin G.N.
Coastal habitats being impacted by the Deepwater Horizon oil spill include beaches, barrier islands, shallow water habitats (seagrass beds and other submersed vegetation), and coastal marshes and estuaries. Some effects of this spill are obvious, but there are more subtle effects of the oil and dispersants that will cascade throughout coastal ecosystems of the Northern Gulf of Mexico, and unfortunately, little is known regarding those complex, ecosystem-level impacts. We are engaged in research that aims to improve understanding of environmental effects of oil and dispersant mixtures on shallow water habitats, wetlands, and beach sediments, and biological degradation of the oil and dispersant mixtures. Our approach is to assess early responses of intertidal habitats to oil/dispersant contamination, and interactions between oil/dispersant systems and soil/sediment microbial assemblages. Remote sensing analyses are being used to develop algorithms for diagnosing stress and/or dieoff of intertidal marsh vegetation. Multiple methodologies are being used to investigate impacts on microbial assemblages, including rates of incorporation of oil/dispersants into microbial biomass, metabolic shifts in the microbial assemblages, and factors influencing microbial metabolism of the oil and dispersants.
Concentration of methylmercury in natural waters from Mississippi using a new automated analysis system
Year: Authors: Brown G., Cizdziel J.
Mercury is a global health concern due to its toxicity, potential to bioaccumulation up the aquatic food chain, and global dispersion through atmospheric pathways. Mercury is mobilized through natural (e.g., volcanism, erosion) and anthropogenic (e.g., combustion of fossil fuels) means. Elemental mercury (Hg<sup>0</sup>), the most long-lived and stable form of mercury in the atmosphere, undergoes photochemical oxidation to the more soluble ionic mercury species (Hg<sup>2+</sup>), which falls to terrestrial and aquatic systems through wet and dry deposition. Sulfate-reducing bacteria, found primarily in low-oxygen aquatic environs, are capable of converting inorganic mercury to the neuro-toxic methylmercury (MeHg) form, which readily concentrates up the aquatic food chain. Human exposure to mercury is primarily through consumption of contaminated fish. In this study, results from a new methylmercury analyzer (Tekran 2700) will be presented. The system uses aqueous phase ethylation, gas chromatography, and atomic fluorescence detection. Samples were collected using clean techniques from areas in the Gulf Coast impacted by the oil spill, and from wetlands and groundwater in northern Mississippi. This poster will present relevant background, an overview of the instrumentation, and compare and contrast results for the saltwater and freshwater samples.
Sustaining Alabama Fishery Resources: A Risk-Based Integrated Environmental, Economic, and Social Resource Management Decision Framework
Year: Authors: Stovall M.E.
The natural systems that make-up Mobile Bay, its watershed, and adjacent marine waters serve as critical natural infrastructure supporting water supply, transportation, power generation, recreation, commercial fishing, agriculture, forestry, and a wide variety of other valued uses for the people in the watershed. Development activities and multiple uses have placed signification stresses on the ecosystem and the sustainable use of its aquatic resources. These stresses have impacted the unique marine and freshwater biodiversity of this aquatic system. <br /><br/ > This paper presents results of Phase 1 of a NOAA funded assessment of the freshwater and marine fisheries of the Mobile Bay watershed, the related aquatic system and the stresses placed on this system by both anthropologic and natural conditions The project is a collaborative effort among government, corporate, and private stakeholders to build the resource management decision support tools needed to assure a sustainable fisheries and coastal seafood industry for Mobile Bay and its watershed, while balancing statewide environmental, economic, and social demands. <br /><br/ > Existing system conditions were initially characterized through review of available literature and agency documents. Two collaborative multi-stakeholder workshops were held in 2009 in order to gain their perspective on the most immediate threats to a sustainable Mobile Bay system. Challenges associated with multi-stakeholder coordination, resource allocation among potentially competing uses, and public education of how human activities potentially impact system health were ranked as higher threats for sustainable system management than more traditional environmental perturbations such as non-point source pollution or aging infrastructure. <br /><br/ > Results from Phase 1 studies have identified tentative indicator species, sources of stresses, model boundary conditions and other major system components for Phase 2 activities to develop a preliminary decision support system, which will link riparian, stream, estuary, and near-shore marine conditions responses to various human use activities via selected indicator species monitoring. The long-term project outcome is to design and develop new tools to model and evaluate social and environmental factors that influence management of a sustainable fishery, support man-made infrastructure investment decisions, and provide a common language for expressing goals, processes, and concerns affecting responsible stewardship of Alabama’s fisheries resources. <br /><br/ > Recent developments incorporating decision impacts of near-shore drilling will also be discussed.
Environmental Mitigation at the Camp Shelby Training Site, MS
Year: Authors: Rasmussen M., Orsi T.H., Dye T., Patrick D., Floyd I., Buck J., Carter G., Newcomb A.
Located in Perry County, MS, the Camp Shelby Training Site (CSTS) faces the challenge of meeting the ever increasing demands of military training to ensure combat readiness while adhering to numerous federal and state environmental laws and regulations. On occasion, training requirements result in unavoidable construction and/or operations within or around environmentally sensitive areas such as wetlands. As an example, construction of the Sonny Montgomery Multi Purpose Range Complex-Heavy (MPRC-H) adversely affected wetlands within its boundaries and resulted in the creation of the Cypress Creek Mitigation Site (CCMS) in the eastern part of the training site. The CCMS is located within the Cypress Creek Watershed that drains into Black Creek. Of the total 246.5 acres, the CCMS consists of 164.7 wetland acres and 81.8 acres of uplands. The CCMS was initially surveyed in 1999 and permitted by the US Army Corps of Engineers Mobile District in 2000. <br /><br /> Physiographically, the CCMS consists of three provinces. The Upland pine flat is characterized by very well drained, non-hydric, fine loamy sand with 55% FACU species, such as the longleaf pine (<em>Pinus palustris</em>). The slope province within the mitigation site is a well drained sandy loam that begins to exhibit stripping in the lower (6-8 inches) portion of the soil profile. This mixed pine-blackgum-oak forest contains 38% FAC and 15% FACU species. Wetland soils at CCMS are a hydric stripped matrix sandy loam that grades into a silty clay loam near a Cypress Creek tributary that traverses the site. This Cyrilla-Cliftonia-Nyssy bottomland is comprised of 39% OBL and 30% FACW species. <br /><br /> Restoration actions at the CCMS have consisted of removing roads and/or fire lanes that might impede water flow into the wetlands, controlled burning to remove unwanted species from both the wetland and upland areas, and removal of pine plantations in certain sections to allow native hydrophytic vegetation to recover or repopulate areas of historical wetland. After two controlled burns, the buckwheat (<em>Cliftonia monophylla</em>) and swamp titi (<em>Cyrilla racemiflora</em>) heavy shrub layer is beginning to thin allowing bald cypress (<em>Taxodium distichum</em>) saplings to emerge as well as numerous forbs and herbs that had been previously shaded out. At least one more controlled burn is needed for the understory to open completely. More recently, girdling has been considered as an alternative to downing large <em>Pinus palustris</em> individuals; the approach would reduce soil water demand, decrease overstory density, and create snag habitat for species that require it for nesting.
Nutrient Modeling of the Big Sunflower Watershed
Year: Authors: Moran M., Young A., Diaz-Ramirez J.
The Mississippi Delta region is filled with fertile farmland formed from rich sediment deposits of the Mississippi River. The Big Sunflower Watershed comprises a large majority (221,270 acres) of the fertile Mississippi Delta region. Approximately 75% of the Big Sunflower Watershed is used for agricultural purposes. The heavy agricultural activity increases the impairment of water bodies due to excess nutrient loads. The excess nutrient loads increases the occurrence of hypoxia and harmful algal blooms. Best Management Practices (BMPs) are a cost-effective way of reducing the non-point source nutrient loads in water bodies. Hydrologic models are to be used to estimate nutrient loads under existing conditions, then estimate the conditions following the implementation of Best Management Practices. Through the use of Better Assessment Science Integrating point & Nonpoint Sources (BASINS) and Hydrological Simulation Program—FORTRAN (HSPF) the nutrient loads in the Big Sunflower Watershed can be effectively modeled. Better Assessment Science Integrating point & Nonpoint Sources (BASINS) is a multi-purpose environmental analysis system that integrates a geographical information system (GIS), national watershed data, and environmental assessment tools into one package. Built into BASINS is the Hydrological Simulation Program—FORTRAN. HSPF simulates the hydrologic and associated water quality processes on pervious and impervious land surfaces and in streams and well-mixed water bodies [USGS]. These tools will be used to conduct a nutrient management study on three sub watersheds within the Big Sunflower Watershed (two sub watersheds of Porters Bayou and one of Harris Bayou). After applying the hydrologic models to the existing conditions, the models will be used to predict nutrient loads after the implementation of BMPs. The Best Management Practices being used are input management, edge of field practices, and constructed wetlands. The nutrient study on these areas will test and validate the hydrologic tools, BASINS/HSPF, for nutrient load predictions in watersheds.
Water Quality and Ecology Research in the Mississippi Delta
Year: Authors: Locke M.A., Knight S.S., Shields Jr. F.D., Moore M.T., Lizotte R.E., Murdock J.N., Cullum R.F., Bingner R.
Research by the USDA Agricultural Research Service (ARS) National Sedimentation Laboratory includes long-term and comprehensive evaluations of conservation practices and assessment of their influence on the water quality and biological health of watersheds in the Mississippi Delta alluvial plain, with extensive plans for future projects beginning to be implemented. Existing ongoing research is part of the ARS national Conservation Effects Assessment Project (CEAP). Data from these studies include soil quality characterizations, cropping patterns, management practices, topography, climate, runoff, ecological assessments, and lake water quality. In addition to direct applications toward resource management, data have also been used in validating predictive computer models of agricultural practices such as AnnAGNPS. With contaminants from agricultural watersheds cited as major contributors to environmental problems such as hypoxia in coastal areas, loss of ecosystem services, and soil and water quality degradation, ARS research includes monitoring of water quality and fish resources and evaluation of runoff from areas where management practices such as CRP and buffer strips are implemented. Focus of the water quality evaluations include not only lacustrine (Beasley Lake project formed from a 915-ha oxbow lake watershed with a 15-year extensive data base) and riverine systems that are part of a network of ARS projects along the Mississippi River that contribute to the Mississippi River Basin Initiative, but also within-field and edge-of-field studies of vegetated agricultural ditches and water retention structures. Planned new research will include ecological assessment of three Mississippi Delta watersheds for the development of science-based TMDLs. This project will be focused on watersheds currently impaired by elevated suspended sediment and turbidity, low dissolved oxygen (DO) concentrations, nutrients and hydrologic perturbations. Watersheds will be monitored for up to three years to gather baseline information and document temporal variability of stream water quality and biological parameters. Following this, each watershed will be subjected to treatment intended to either reduce or increase biotic impairment. Candidate treatments include flow augmentation, flow diversion through wetlands, the establishment of within stream structures, agronomic conservation practices or simulated pollution events. Resulting changes in water quality, habitat and biological community will be observed. In addition to general ecological benefits, this research in the Mississippi Delta is expected to benefit a large number of stakeholders, including farmers, Delta FARM, Delta Wildlife, Delta Council, Mississippi Soil and Water Conservation Service, the Yazoo-Mississippi Delta Water Management District, Mississippi Department of Environmental Quality, USEPA, and USDA-NRCS.
Mercury Deposition in Northern Mississippi Wetlands using Sediment Cores and Thermal Decomposition, Amalgamation, and Atomic Absorption Spectrometry
Year: Authors: Chakravarty P., Cizdziel J.
Mercury, a non essential element with a complex biogeochemical cycle, has emerged as a serious public health concern in Mississippi. Fish consumption advisories were issued for the Enid Reservoir in May 1995 and Yocona River in September 1996. The origin of Hg in these water bodies is unclear but may include atmospheric deposition, geological formations that leach Hg into the watershed, and historic land use practices. The atmosphere is recognized as an important source of trace metals to aquatic ecosystems through wet and dry deposition. Sediments constitute an important storage compartment for the inorganic forms of mercury that are precursors of the toxic and bioaccumulatable methylated form generated primarily by sulfate-reducing bacteria. In sediments, mercury is normally present at low concentrations typically ranging from 0.003–4.6 mg/kg. In this study, intervals of sediment cores from wetlands in northern Mississippi were analyzed for total mercury using a direct mercury analyzer based on combustion, amalgamation with gold, and atomic absorption spectrometry. The goal is to determine the extent of mercury contamination in the wetlands and search for temporal and spatial patterns of mercury deposition. This poster will discuss the technology and presents results for the various samples.
Regional Sediment Management Plan
Year: Authors: Clifton N.
The Mobile Bay watershed covers two thirds of the state of Alabama and portions of Mississippi, Georgia, and Tennessee. It is the fourth largest watershed in the United States in terms of flow volume and is the sixth largest river system in the U.S. in terms of area. The lower Mobile Bay is a designated national estuary under the EPA’s National Estuary Program. The Mobile Bay and the rivers draining into it support major uses with national implications which include the Tennessee-Tombigbee Waterway, the Port of Alabama, various commercial fisheries, large industry, tourism and recreation, and abundant development. Water in the upper-most reaches of the watershed makes its way to the Gulf of Mexico through Mobile Bay. Throughout this process sediments and nutrients are transported and deposited along the way. It is important to understand the mechanisms and processes of how sediments move through the entire watershed to aid in making informed management decisions relating to sedimentation, water quality, environmental resources, habitat management, and human uses. <br /><br /> One of the primary tasks of the Mobile Basin Regional Sediment Management project is to develop a Regional (Watershed) Sediment Management Plan to provide the necessary elements for the management of sediment resources while considering environmental restoration, conservation, and preservation. The plan is intended to also maximize interagency collaboration to assess current management practices towards improving water quality and optimize beneficial use of sediment resources. The management plan will: <ul><li>Develop understanding of system dynamics and provide for better management of resources in the region including sources, movement, sinks, related watershed and coastal processes, and influences of structures and actions that affect sediment movement, use, and loss</li> <li>Provide guidelines and recommendations towards a holistic watershed management approach</li> <li>Encourage more effective management of watershed resources, recognizing they are a part of a regional system involving natural processes and man-made activities.</li> <li>Develop technical framework that provides the foundation associated with holistic watershed processes</li> <li>Provide understanding of regional sediment systems and processes</li> <li>Facilitate cooperation among stakeholders to enhance abilities to make informed cooperative management decisions and develop regional strategies across jurisdictional boundaries.</li></ul>
Asset Management Assistance for the City of Bay St. Louis
Year: Authors: Tagert M.L., Ballweber J., Manuel R.
The Southeast Regional Small Public Water Systems Technical Assistance Center (SE-TAC), located at Mississippi State University and established via funding from the Environmental Protection Agency, is working with the City of Bay St. Louis and the Hancock County Utility Authority on an asset mapping and management demonstration project. This project builds on the implementation of Mississippi’s post-Katrina Gulf Regional Utility Plan and the creation of five (5) new county-wide utilities. This project will map the construction of the City’s post-Katrina water supply infrastructure and aid in its integration into the new Hancock County Utility Authority’s asset management system. The results of this effort will be immediately transferable to other coastal small public water systems and county-wide utilities in Mississippi. SE-TAC is working with the private sector to identify and assess public domain asset mapping and management tools. An evaluation matrix will be developed to compare various aspects of the available tools, such as hardware requirements, ease of use, expandability, training requirements, and more. The highest ranking public domain tool(s) will be applied to a defined subset of the City’s new drinking water infrastructure and integrated, to the extent possible, with the newly established Hancock County Utility. Results and lessons learned will be compiled in a final report to help accelerate adoption of asset mapping and management tools by small public water systems throughout Mississippi and the SE-TAC region.
Evaluating Physiological and Growth Responses of <em>Arundinaria</em> spp. to Inundation
Year: Authors: Mills M.C., Ervin G.N., Baldwin B.S.
The genus <em>Arundinaria</em> includes three species: <em>Arundinaria gigantean</em> (Walter) Muhl. (rivercane), <em>Arundinaria tecta</em> (Walter) Muhl. (switchcane) and <em>Arundinaria appalachiana</em> Triplett, Weakley, & L.G. Clark (hillcane). <em>Arundinaria gigantean</em> and <em>A. tecta</em> are both found in Mississippi, but in slightly different habitats. <em>Arundinaria gigantean</em> typically occurs on the floodplains of large to small rivers, sometimes on the edge of mesic slopes, while <em>A. tecta</em> usually occurs along small to medium blackwater rivers and in small seepages with organic soils. Thus, <em>A. tecta</em> usually is found on moister sites than <em>A. gigantean</em>. Our study assessed the responses of <em>A. gigantean</em> and <em>A. tecta</em> to different periods of inundation (0-week, 2-week, 4-week, and 6-week) under greenhouse conditions. Plant growth parameters, mean net photosynthesis (Pn), and stomatal conductance (Gs) were measured on a weekly basis for each ramet. At the conclusion of the experiment, cane biomass, including root and rhizome mass, were measured. Once flooded, <em>Arundinaria</em> spp. ramets in the 6-week flood treatment had lower Pn rates than those ramets not flooded. During the last week of flooding, <em>A. tecta</em> had a higher Pn rate than <em>A. gigantean</em>. Once flooding was stopped, <em>A. tecta</em> continued to have higher Pn and Gs rates than <em>A. gigantean</em>. Additionally, <em>A. tecta</em> grew more culms post-flood than <em>A. gigantea</em>. In conclusion, <em>A. tecta</em> appeared to be more flood tolerant than <em>A. gigantea</em>, in agreement with habitats in which <em>A. tecta</em> is known to occur. This research should contribute to improving the success of future canebrake restoration projects by increasing understanding of cane’s tolerance of inundation as well as aiding decisions of land managers choosing potential restoration sites or restoration species, based on hydrologic conditions.
The Fate and Transport of Nitrate in the Surface Waters of the Big Sunflower River in Northwest Mississippi
Year: Authors: Wood M., Coupe R.H.
The Mississippi Alluvial Plain, an area lying within the Yazoo River basin in northwestern Mississippi, locally referred to as the Delta, is a relatively flat landscape where approximately 90 percent of the land is used for cultivation of corn, cotton, rice, soybeans, and catfish. Annually, the Yazoo River basin contributes around 1–3% of the nitrogen load to the Gulf of Mexico. Recent modeling studies suggest that that there is very little processing of nitrogen in the main channel and primary tributaries of the Yazoo River basin; nitrogen acts conservatively and does not undergo significant reduction through processes such as denitrification. The nitrogen loss rates used in these models are from other areas as there have been few studies on denitrification rates in the Delta. The Delta, which differs from the topography and climate of most of the rest of the United States, has slower stream velocities and higher temperatures than many areas of the United States; two key variables that control denitrification rates. If there is significant processing of nitrogen in the streams of the Yazoo River basin, this could have implications for managing nutrient reduction in streams and rivers of the Delta. During April–August 2010, four sets of samples were collected at ten sites located on the Big Sunflower River. Samples were analyzed for nitrate, nitrite, organic nitrogen, total nitrogen, chloride and sulfate. A Lagrangian procedure that followed the same parcel of water as it transited the Big Sunflower River was used to time the collection of the water samples. The objective of the study is to determine if nitrogen, once in the Big Sunflower River, is conservative in nature or undergoes significant loss.
Refining effective precipitation estimates for a model simulating conservation of groundwater in the Mississippi Delta Shallow Alluvial Aquifer
Year: Authors: Wax C.L., Pote J.W., Thornton R.F.
The shallow alluvial aquifer in the Mississippi Delta region is heavily used for irrigation of corn, soybeans, and cotton, as well as for rice flooding and filling aquaculture ponds in the prominent catfish industry. Water volume in the aquifer is subject to seasonal declines and annual fluctuations caused by both climatological and crop water use variations from year-to-year. <br /><br /> Available climate, crop acreage, irrigation water use, and groundwater decline data from the 19 counties in the Delta were used to construct a model that simulates the effects of climatic variability, crop acreage changes, and specific irrigation methods on consequent variations in the water volume in the aquifer. Climatic variability was accounted for by predictive equations that related annual measured plant water use (irrigation) to total growing season precipitation amounts. This derived relationship allowed the application of a long-term climatological record (50 years) to simulate the cumulative impact of climate on groundwater use for irrigation. <br /><br /> The relationship between rainfall and anticipated crop water use was initially estimated by a simple regression between total growing season rainfall and measured irrigation water use for the period 2002-2007, with a resulting R<sup>2</sup> value of 0.93. Adding data from 2008 caused R<sup>2</sup> to drop to 0.63. It was recognized that total growing season rainfall was not representative of the timing, or episodic nature, of rainfall compared to plant water demand day-by-day through the growing season. To account for this timing issue, weekly rainfall amounts were compared to weekly expected crop water demand to produce an effective rainfall estimate. The resulting improvements are shown. This effective rainfall compared to irrigation use is expected to provide a much-improved rainfall-irrigation coefficient for use in the model.
Water quality and other ecosystem services from wetlands managed for waterfowl in Mississippi
Year: Authors: Kaminski R.M., Spencer A.B.
A successful and increasingly applied conservation practice in the Lower Mississippi Alluvial Valley (MAV) to mitigate loss of wetland wildlife habitat and improve water quality has been development and management of "moist-soil wetlands." Whereas a primary goal of moist-soil management is to provide abundant food resources for waterfowl and other waterbirds in the MAV and elsewhere on the wintering and migrational grounds, this conservation practice has the potential to provide ecosystem services critical to restoring ecosystem functions in the MAV. Within the MAV, strategic location of natural moist-soil wetlands amid farmed lands can reduce dispersal of sediments and other nutrients into surrounding watersheds. Moreover, a significant potential exists for native crayfish (<em>Procambarus</em> spp.) harvest in moist-soil wetlands in the MAV. Our current research is designed to quantify nutrient management and crayfish harvest as ecosystem services provided by moist-soil wetland management in the MAV. During spring 2009, we estimated baseline water quality parameters and average daily yield of crayfish from 9 moist-soil wetlands in Mississippi. Mean NO<sub>3</sub>-N, NH<sub>4</sub>-N, and PO<sub>4</sub>-P concentrations were variable whereas total suspended solid concentrations decreased over time. Average daily yield of crayfish was 1.75 kg ha<sup>-1</sup> (CV = 16%, n = 9). We continued our study in spring-summer 2010 in wetlands in Arkansas, Louisiana, and Mississippi. Preliminary estimates of average daily yield of crayfish in 2010 was 2.18 kg ha<sup>-1</sup> (CV = 30%, n = 15). In July 2010, we installed water quality monitoring stations at 6 wetlands and 6 agriculture fields. We will use the data from these stations to estimate and compare monthly loads (kg ha<sup>-1</sup>) of nutrients and solids from moist-soil wetlands and flooded agricultural fields. Quantifying these ancillary ecosystem services of moist-soil wetlands will encourage further establishment and management of these wetlands in the MAV and elsewhere for wildlife and associated environmental benefits.
Evaluation of Two Different Widths of Vegetative Filter Strips to Reduce Sediment and Nutrient Concentrations in Runoff from Agricultural Fields
Year: Authors: Ramirez-Avila J.J., Ortega-Achury S.L., Sotomayor-Ramirez D.R., Martinez-Rdoriguez G.A., Mas E.G.
A vegetated filter strip (VFS) is intended to remove pollutants from runoff flowing through it as sheet flow. VFS can be effective in reducing sediments and associated pollutants such as hydrocarbons, metals and nutrients through sedimentation and filtration. Soluble pollutants may also be removed through uptake by vegetation. In a properly designed VFS, water flows evenly through the strip, slowing the runoff velocity and allowing contaminants to settle from the water. In addition, where VFS are established, fertilizers and herbicides no longer need to be applied right next to susceptible water sources. Vegetative filter strips also increase wildlife habitat. This study evaluated the relationship between VFS width and trapping efficiency for sediment, phosphorus and nitrogen and to produce a design aid for use where specific water quality targets must be met. Runoff collection devices were placed at 0, 10 and 20 m within a grassed VFS established at the outlet of two dairy farm fields in Puerto Rico, which received periodic application of inorganic and dairy sludge irrigated amendments. Collected runoff samples were analyzed for suspended solids (SS), dissolved phosphorus (DP), total phosphorus (TP) and total Kjeldahl nitrogen (TKN) concentrations. Nutrients concentrations high above environmental targets were observed in runoff events that occurred within 10 days after organic amendment irrigation. Runoff DP and TP concentrations were significantly reduced, while an important but not significant reduction in runoff TKN concentration was observed at the wider VFS. Results showed that SS concentrations in runoff were not significantly reduced because the entering concentrations were minimal. The 20-m VFS wide was effective to reduce runoff nutrient concentrations below target levels; however other best management practices (BMPs) such reducing application volumes but increasing frequency of application and by spreading and/or irrigating the amendments on dates when significant precipitation events are less expected, are needed to reduce the potential impact of nutrient losses on water quality of waterbodies.
Water-Conserving Irrigation Systems for Furrow and Flood Irrigated Crops in the Mississippi Delta
Year: Authors: Massey J.H.
The goal of this on-going project is to determine the feasibility of using multiple inlet plus intermittent irrigation to reduce water and energy use in Mid-south rice irrigation. Intermittent rice flooding improves rainfall capture and reduces over-pumping by maintaining rice flood heights at less-than-full levels. Depending on soil conditions, weather, and crop stage, the targeted intermittent pumping pattern allows the flood to naturally subside over a period of five to ten days before re-initiating irrigation, resulting in a fully saturated (not dry) soil surface. Field studies are being conducted at four Mississippi producer locations location in Boliver, Coahoma, and Sunflower counties in the Mississippi River Valley delta. Seasonal water use was measured using flow meters in commercial rice fields ranging in size from ~30 to 70 acres. Rainfall inputs were determined using rain gauges at each field location. Rough rice yield and grain quality determined for the upper and lower portions of each paddy of each field were not different, indicating that intermittent flooding does not result in agronomic losses relative to continuous flood. The studies show that when coupled with multiple inlet irrigation, intermittent rice irrigation uses ~20% less water than multiple inlet irrigation alone and only ~5% more than zero-grade irrigation. Having no slope, zero-grade fields are the ‘gold standard’ for Mid-south rice production in terms of water use. The advantage of the intermittent flood over zero-grade is that water-logging of rotational crops often associated with zero-grade fields is avoided. Rice is typically grown with soybean in a 1-yr rice, 2-yr soybean rotation. The presentation will also summarize results from using the USDA’s Phaucet irrigation optimization program designed to improve soybean irrigation efficiency.
Water Use Conservation Scenarios for the Mississippi Delta Using an Existing Regional Groundwater Flow Model
Year: Authors: Barlow J.R., Clark B.R.
The alluvial plain in northwestern Mississippi, locally referred to as the Delta, is a major agricultural area, which contributes significantly to the economy of Mississippi. Land use in this area can be greater than 90 percent agriculture, primarily for growing catfish, corn, cotton, rice, and soybean. Irrigation is needed to smooth out the vagaries of climate and is necessary for the cultivation of rice and for the optimization of corn and soybean. The Mississippi River Valley alluvial (MRVA) aquifer, which underlies the Delta, is the sole source of water for irrigation, and over use of the aquifer has led to water-level declines, particularly in the central region. The Yazoo-Mississippi-Delta Joint Water Management District (YMD), which is responsible for water issues in the 17-county area that makes up the Delta, is directing resources to reduce the use of water through conservation efforts. The U.S. Geological Survey (USGS) recently completed a regional groundwater flow model of the entire Mississippi embayment, including the Mississippi Delta region, to further our understanding of water availability within the embayment system. This model is being used by the USGS to assist YMD in optimizing their conservation efforts by applying various water-use reduction scenarios, either uniformly throughout the Delta, or in focused areas where there have been large groundwater declines in the MRVA aquifer.
Occurrence of phosphorus in groundwater and surface water of northwestern Mississippi
Year: Authors: Welch H.L., Kingsbury J.A., Coupe R.H.
Previous localized studies of groundwater samples from the Mississippi River Valley alluvial (MRVA) aquifer have demonstrated that dissolved phosphorus concentrations in the aquifer are much higher than the national background concentration of 0.03 milligram per liter (mg/L) found in 400 shallow wells across the country. Forty-six wells screened in the MRVA aquifer in northwestern Mississippi were sampled from June to October 2010 to characterize the occurrence of phosphorus in the aquifer, as well as the factors that might contribute to high dissolved phosphorus concentrations in groundwater. Dissolved phosphorus concentrations ranged from 0.12 to 1.2 mg/L with a median concentration of 0.62 mg/L. The predominant subunit of the MRVA aquifer in northwestern Mississippi is the Holocene alluvium in which median dissolved phosphorus concentrations were higher than the Pleistocene valley trains deposits subunit. Highest phosphorus concentrations occurred in water from wells located along the Mississippi River. A general association between elevated phosphorus concentrations and dissolved iron concentrations suggests that reducing conditions that mobilize iron in the MRVA aquifer also might facilitate transport of phosphorus. Using baseflow separation to estimate the contribution of baseflow to total streamflow, the estimated contribution to the total phosphorus load associated with baseflow at the Tensas River at Tendal, LA, and at the Bogue Phalia near Leland, MS, was 23 percent and 8 percent, respectively. This analysis indicates that elevated concentrations of dissolved phosphorus in the MRVA aquifer could be a possible source of phosphorus to streams during baseflow conditions. However, the fate of phosphorus in groundwater discharge and irrigation return flow to streams is not well understood.
Watershed Characterization of the Big Sunflower Watershed
Year: Authors: Young A., Moran M., Diaz-Ramirez J.
The emergence of excess nutrient loads in water bodies in the Mississippi Delta has led to their appearance on the 303(d) listing of impaired waters for Mississippi. This project aims to develop and improve analytical tools for the evaluation of nutrient load reductions expected from the implementation of best management practice (BMPs) on some of these water bodies in the delta. In compliance with the Delta Nutrient Reduction Strategies developed by Delta Farmers Advocating Resource Management (F.A.R.M.) and the Mississippi Department of Environmental Quality (MDEQ) the first step in this process is the characterization of the watershed including geology, land use, soil type, hydrology, and water quality issues. The area of study for this project is three sub watersheds within the Big Sunflower Watershed. The Big Sunflower Watershed is the largest watershed in the delta at 221270 acres and is a part of the Yazoo River Basin. Significant characteristics for the watershed were found to be a dominance of agricultural land, poorly drained soils, and the persistence of impaired waters due to extreme nutrient loads. Examination of historical trends shows a decline in the state of the groundwater aquifer and the constant persistence of agricultural land as the major land use type. Availability of nutrient data for the watershed is incredibly limited making it difficult to draw conclusions by comparing past flow and land use data to the occurrence of nutrients in the water bodies of the Big Sunflower Watershed.
Study of Seagrass Beds at Grand Bay National Estuarine Research Reserve
Year: Authors: Nica C., Cho H.J.
Submerged aquatic vegetation (SAV), a unique group of flowering plants that have adapted to live fully underwater, is a valuable resource and indicator of aquatic habitat quality. Coastal SAV beds perform a number of irreplaceable ecological functions in chemical cycling and physical modification of the water column and sediments. They also provide food and shelter for commercial, recreational, and ecologically important organisms. The cumulative effects of alteration of natural habitats and decline in coastal environmental quality are causing a decline of coastal SAV. In Mississippi Sound, seagrass beds have reportedly declined >50% since the 1969 Hurricane Camille. In addition, the more significant declines occurred in stable, climax community seagrasses such as Turtlegrass (<em>Thalassia testudinum</em> K.D. Koenig) and Manateegrass (<em>Syringodium filiforme</em> Kutzing), which have resulted in the increased relative abundance of opportunistic, pioneer species such as Wigeongrass (<em>Ruppia maritime</em> L.) and Shoalgrass (<em>Halodule wrightii</em> Aschers) in estuaries and along barrier islands of the northern Gulf of Mexico. Temporal changes in their distribution and abundance indirectly reflect changes in the habitat quality and environmental health status. In this study we are presenting data on seagrass community dynamics by following patterns of biomass allocation at three sites at Grand Bay National Estuarine Research Reserve (NERR), Mississippi. Other pertinent water quality parameters—turbidity, [chlorophyll <em>a</em>], dissolved color, dissolved oxygen, pH, salinity, temperature, sediment, nutrients, and water level were monitored or obtained from the NERR monitoring data. Total biomass and root to shoot ratio were significantly different among the sites, with species composition (<em>R. maritime</em> dominant or <em>Ruppia-Halodule</em> mixed beds) being the most important explanatory variable. The general seasonal pattern showed that the biomass began to increase in April, and peaked in May-June, then decreased in September as <em>Rupppia</em> senesces. Our results suggest that fresh water regime due to precipitation and predominant wind direction might be one of the environmental factors contributing to the spatial difference.
Rates and Processes of Streambank Erosion along the Principal Channel of the Town Creek Watershed: Implications in a Sediment Budget Development
Year: Authors: Ramirez-Avila J.J., Langendoen E.J., McAnally W.H., Ortega-Achury S.L., Martin J.L.
A combination of <em>in situ</em> monitoring and characterizing methods were performed on different locations along the principal channel of the Town Creek in Northeastern Mississippi to quantify the contributions of streambanks to stream sediment loads and better understand the processes of streambank erosion. Results and field observations demonstrate that streambank instability is widespread and the highly erodibility of the streambank materials made streambanks important potential sources of sediment along the entire watershed. Streambanks predominantly lost materials through gravitational failures and removal of sediments by hydraulic forces along the watershed headwaters, commonly represented as incised channels near agricultural areas. Headwaters would represent up to 70% of the total sediment load exported from the entire watershed. Changes in channel morphology, vegetation and streamflow patterns favored the significant amount of sediment deposition amounts observed along the middle area of the watershed. Reduction of suspended sediment loads should focus on the attenuation of geomorphic processes and stabilization of reaches and agricultural lands near streambanks at the headwaters within the Town Creek watershed. Observed results and modeling process offer important insights into the relative effects of land and streambank erosion on the sediment budget for Town Creek watershed, on stream water quality and how management measures can effect improvements.
Water Supply in the Mississippi Delta: What the Model Has to Say
Year: Authors: Mason P.
A regional groundwater flow model has been built as a tool to better understand the system flows and to project future water levels in the Missisippi River Valley alluvial aquifer (MRVA). This is a highly productive aquifer which supports vast amounts of agriculture and aquaculture in northwest Mississippi. Water levels are declining in this aquifer and will be of increasing concern in the future. <br /><br /> To quantify discharge, the model incorporates a method of estimating pumpage for agriculture and aquaculture, based on crop distribution patterns and rainfall-response factors. <br /><br /> Recharge to the aquifer is complex and unusual, since a widespread impermeable surficial unit restricts rainfall infiltration in most of the Delta plain. Good calibration was achieved only when the model fully accounted for recharge data from several sources. Positive recharge sources are: groundwater in the adjoining formations on the eastern bluff hills line, rain infiltration through the alluvial fans along the bluffline, and rain infiltration through sandy areas along the Mississippi River. <br /><br /> Other sources serve as both discharge and recharge areas for the aquifer, depending on season and/or location. These are: the Mississippi River, the underlying Tertiary aquifers (Cockfield and Sparta), the major rivers and the bluffline streams. <br /><br /> The base model period, built from known data for streams, precipitation, crops, and water levels, etc. ran 1996 through 2006. On average, the aquifer lost about 230,000 acre-ft of water per year from 1996 to 2006. During this time, pumpage per season averaged about 3 million acre-feet, with a minimum of 1.7 million acre-feet in 2002 and a maximum of 4.5 million acre-feet in 2000. Rainfall infiltration averaged about 2.4 million acre-feet per water-year, with a low of 1.9 million acre-feet in 1998 to a high of 3 million acre-feet in 2003. Over the ten year period, there were 2 years during which rainfall infiltration exceeded pumpage. In 8 of the years pumpage exceeded rainfall infiltration. <br /><br /> Several scenarios have been run from 2009 water levels forward, simulating conditions 20 years into the future, and the results of these are presented.
Spatially Distributed Sediment and Nutrients Loading from the Upper Pearl River Watershed
Year: Authors: Parajuli P.
Sediment and nutrients loading from the non-point sources of agricultural and non-agricultural activities contribute to water quality degradation. Developing sediment and nutrients Total Maximum Daily Loads require quantifying pollutant load contribution from each potential source. The determination of pollutants reduction strategies from each source is required to meet applicable water quality standards. The watershed-scale evaluation of the effects of the agricultural, and pasture management practices on water quality can be estimated using watershed water quality models. <br /><br /> The objective of this research was to evaluate spatially distributed sediment and nutrients loading from the Upper Pearl River watershed (UPRW-7,885 km<sup>2</sup>) in east-central Mississippi using modeling approach. Nutrient sources from agricultural and non-agricultural activities of the UPRW were analyzed and model inputs were developed. The Soil and Water Assessment Tool model was calibrated, and validated in the UPRW to evaluate sediment, and nutrients loading. The model results were evaluated against monthly observed water quality values using coefficient of determination (R<sup>2</sup>), and Nash-Sutcliffe Efficiency Index (E).
Results of Monitoring Sediment Concentration and Loads Pre and Post BMP Implementation
Year: Authors: Hicks M., Stocks S.
The Mill Creek watershed in Rankin County, Mississippi, drains 6,200 acres and flows into Pelahatchie Bay of the Ross Barnett Reservoir. In the last twenty years, the watershed has experienced a large amount of urban growth and development. As a result of this landscape change, non-point source pollution concerns to the health of Mill Creek, its tributaries, and Pelahatchie Bay have emerged. A locally led watershed implementation team developed a plan that identified primary pollutants to Mill Creek watershed and outlined restoration activities necessary to restore the watershed to healthy conditions. Erosion and increased sedimentation were identified as primary and immediate concerns to the health of Mill Creek watershed and to the health and fisheries of Pelahatchie Bay. Strategies implemented to address sediment loading to Mill Creek included a range of activities such as bank stabilization, flow control structures, slope drains, ditch stabilizations, check dams, and storm-water runoff compliance and enforcement actions. Beginning in 2006, the U.S. Geological Survey, in cooperation with Rankin County Board of Supervisors and Mississippi Department of Environmental Quality, began collecting water quality and streamflow data at six fixed stations in the watershed. The purpose of data collection was to document changes in suspended sediment concentrations and loads in Mill Creek and its tributaries before and after watershed restoration activities were implemented. Monitoring included the collection of stream flow, suspended-sediment concentration, and precipitation data. Preliminary data analysis suggests a decrease in sediment concentrations and loads, which may be attributable to watershed restoration activities.
Plan for Monitoring Success of Mississippi’s Delta Nutrient Reduction Strategy
Year: Authors: Hicks M., Stocks S., Wright J.
A multi-agency task force forum, The State Nutrient Strategy Work Group, was formed in 2009 for the purpose of developing a consistent approach among Mississippi/Atchafalaya River Basin states to reduce nutrient loadings from streams and rivers draining into the Gulf of Mexico. As part of this forum, a nutrient reduction strategy for the Delta region in northwestern Mississippi was developed. One of twelve critical elements identified in the nutrient reduction strategy was to implement "Monitoring Programs" for the purpose of documenting nutrient concentration and load reductions, lag times, and watershed system responses. To address this element, two project areas were identified: Harris Bayou watershed, Coahoma County, MS, and Porter Bayou watershed, Sunflower County, MS. Project areas were chosen based on areas where there has been historically high nutrient concentrations and where land-owners are willing to participate in this effort. These two watersheds are also located in a focus area watershed of the Mississippi River Basin Initiative. Efforts have begun to implement various Best Management Practices (BMPs) in four catchments, two in each of Harris and Porter Bayous, for the purpose of improving water quality by reducing nutrient loading to streams affecting downstream aquatic ecosystems. In 2010, the U.S. Geological Survey, in cooperation with Mississippi Department of Environmental Quality, U.S. Army Corps of Engineers, and Delta Farmers Advocating Resource Management (F.A.R.M.) began implementation of a monitoring strategy at two stations in Porter Bayou watershed and four stations in Harris Bayou watershed. The strategy involves monitoring before and after BMPs have been implemented, as well as using a paired basin approach for data analysis of changes due to the BMP project. Data collection activities at each site include base and storm flow sampling for flow, total nitrogen and other nitrogen species, total phosphorus, suspended sediment, and other physical and chemical water quality indicators of ecosystem health, including response indicators such as benthic macroinvertebrate community assemblages and chlorophyll-a concentrations.
Evolution of Surface Water Quantity Issues in the Mississippi Delta
Year: Authors: Byrd C.B.
Over the last ten to twenty years, most of the streams in the interior of the Mississippi Delta have lost most, if not all, of their base flow from the shallow aquifer that is used for irrigation and fish culture. There are several reasons for this situation, some of which date all the way back to the early 1900s and perhaps even as far back as the mid 1800s. <br /><br /> Shortly after Mississippi became the nation’s 20th state in 1817, settlers began coming to the Delta area to try to establish a new life for themselves and their families. They found vast swamps and thick, thick forests. Most of these first pioneers arrived between 1825 and 1827 and brought with them the means of making a living they had known all their lives—cotton farming. But before they could farm, they had to clear the land. Then once the land was cleared, drainage was a tremendous problem. As far back as the early 1900s, farmers banded together to form drainage districts. Within these drainage districts, they voluntarily taxed themselves so that drainage ditches could be dug to take excess water more quickly to the nearest Delta streams. <br /><br /> Approximately 9.2 million acres of forest in the Lower MS Valley had been removed. And even by the 1960’s, areas that were frequently flooded, but were mostly undisturbed, were converted from forests to fields as a result of federal agencies’ flood control projects. As virgin forests disappeared, farmland increased. For many, many years cotton was considered the King of all the crops grown in the Delta. In 1950 soybeans and rice began to be grown. Then in the early 1960s catfish farming developed as an important source of income. <br /><br /> With more land dedicated to crops other than cotton, especially rice and catfish, irrigation from groundwater became extremely important. The volume of water pumped from the shallow aquifer known as the Mississippi River valley alluvial aquifer, or MRVA, has increased significantly from approximately million gallons per day annually in 1954 to a current estimate of perhaps as much as 1.5 billion gallons of water per day. <br /><br /> Along with the increased usage of the MRVA, there has been a decrease in the water level in this aquifer. So much so that at least for the northern half of the Delta, the water level has fallen below the channel bottoms of the interior streams—thus causing baseflow from the aquifer to those streams to either be reduced significantly or to totally disappear.
Relation between Chromophoric Dissolved Organic Matter (CDOM) and Salinity in the Mississippi Sound
Year: Authors: Martin C.L., Milroy S.P.
While several studies on chromophoric dissolved organic material (CDOM) have been conducted in a variety of coastal regions throughout the world, only a handful have focused in the area of the northern Gulf of Mexico (Bissett et al, 1999, Chen et al, 2004, Ohlmann et al, 2005, Zanardi-Lamardo et al, 2004). Fed by the Mississippi River plume to the southwest as well as Pearl River, Biloxi Bay, Pascagoula River, and Mobile Bay effluents, the Mississippi Sound represents a dynamic and under-explored area for the study of nearshore CDOM and the correlated watersheds. Over a series of cruises conducted from 01 APR– 30 JUL 2010, a spectrophotometric determination of surface CDOM was enjoined using comparative filtration and centrifugation methods. Ultimately, a simple algorithm of the CDOM absorption coefficient <em>a<sub>cdom</sub></em>(λ) was developed to help resource managers and Marine GIS professionals characterize the optical properties of nearshore waters within the MS Sound using simple salinity measures as a means to estimate <em>a<sub>cdom</sub></em>(λ) using visible and near-IR spectra.
Quantification of groundwater contributions to the Bogue Phalia in northwestern Mississippi using an End-member mixing analysis
Year: Authors: Rose C.E., Detavernier A.C., Coupe R.H.
End-member mixing analyses use chemical signatures of water sources to determine the contribution of each source to a stream. Low flow in the Bogue Phalia, a river in northwestern Mississippi, during the summer season is typically from two primary sources; (1) baseflow from shallow groundwater and bank storage, and (2) irrigation return flow. Irrigation return flow originates from the Mississippi River Valley alluvial aquifer’s deep irrigation wells. This water has sometimes been shown to have dissolved phosphorus concentrations (0.01 to 1.0 mg/L), and sometimes have exceeded the USEPA surface water criteria. There is concern that irrigation return flow might be adversely affecting the quality of the surface water. The chemical signature of the shallow groundwater was determined from water samples collected from the Bogue Phalia in the fall, during baseflow. Water samples from the alluvial aquifer were used to determine the chemical signature of the irrigation return flow. These two water sources have distinctly different specific conductance values; this enabled the determination of the contribution of water from both sources to the Bogue Phalia during the irrigation season, when the influence of rainfall or other water sources would be minimal. An end-member mixing analysis was used to estimate of the percentage of both water sources. From this method, which consisted of the use of a numerical formula, discharge and continuous specific conductance data from the Bogue Phalia from 2001 to 2008, the influence on the in-stream concentration of phosphorus from irrigation return flow can be determined.
Effects of the BioFuels Initiative on Water Quality and Quantity in the Mississippi Alluvial Plain
Year: Authors: Welch H.L., Coupe R.H.
In the search for renewable fuel alternatives, biofuels have gained strong political momentum. In the last decade, extensive mandates, policies, and subsidies have been adopted to foster the development of a biofuels industry in the U.S. The manifestation of the Biofuels Initiative in the Mississippi Delta was a 47-percent decrease in cotton acreage with a concomitant 288 percent increase in corn acreage in 2007. Because corn uses 60 percent more water for irrigation than cotton, and more nitrogen fertilizer is recommended for corn cultivation, this crop type change has implications for water quantity and quality in the Delta. Increased water use for corn is accelerating water-level declines in the Mississippi River Valley alluvial aquifer at a time when conservation is being encouraged due to concerns about sustainability. A mathematical model calibrated to existing conditions in the Delta shows that increased fertilizer applications on corn will increase the extent of nitrate movement into the alluvial aquifer. Estimates based on surface-water modeling results indicate that higher application rates of nitrogen from increased corn production increases the amount of nitrogen exported from the Yazoo River basin to the Gulf of Mexico by about 7 percent; increasing the Delta’s contribution to hypoxic conditions in the Gulf of Mexico.
The Influences on the Capacity Development Assessment Scores of Publicly-Owned Drinking Water Systems in Mississippi
Year: Authors: Barrett J., Barefield A.
The Capacity Development Assessment (CDA) is a focused survey instrument used to quantify the financial, managerial and technical factors of a water system in Mississippi. The survey’s primary focus is identifying the extent to which water systems are complying with Mississippi State Department of Health-Bureau of Public Water Supply regulations and standards. Since the majority of the factors for publicly owned water systems (municipal systems and water associations and districts) measured in the CDA are either directly or indirectly influenced by board management decisions as well as other, more macro/regional external influences such as per capita income, water system population, county population, operator experience, etc., we propose to examine causal influences on the CDA score. Identification of these influences could lead to future local and state policy implementation and educational efforts to strengthen public water systems.
The Chickasawhay River: A Small Mississippi Stream vs. the U.S. Army Corps of Engineers
Year: Authors: Buck J., Orsi T.H., Rasmussen M., Newcomb A., Carter G.
There has been recent interest in improving the recreational value of the Chickasawhay River in Clarke County, MS, by removing large wood obstructions from the stream channel. The Pat Harrison Waterways District conducted an initial survey in 2002 and commissioned a follow-up in 2004, determining in both instances, that such a project would be extremely costly and ill-advised. None-the-less, the project proceeded from 2006-2008. Our purpose is not to speculate on whether the project was environmentally or financially appropriate, nor is it an attempted indictment of the agencies involved, past or present. Instead, we look to the historical record, seeking any information that might provide insight into the potential long-term success of a project like that conducted recently on the Chickasawhay. <br /><br /> Interestingly, "improvements" to the Chickasawhay River began over 100 years ago. Initial examination from Subuta to its confluence with the Leaf River began in 1878-1879 by the U.S. Army Corps of Engineers (USACE). This was followed a decade later (1888-1889) with an examination of the reach from Enterprise to Bucatunna. Both surveys concluded that the Chickasawhay was "badly obstructed by logs, snags, overhanging trees, shoals, etc." Regardless, the stream was considered "worthy of improvement by the United States" and a project began in 1890 to provide for high-stage navigation from Shubuta to the Leaf-Chickasawhay confluence. <br /><br /> Based on available Annual Reports to the Chief of Engineers, there are three general phases of USACE engagement with the Chickasawhay: (1) Improvement (1890-1900); (2) Maintenance (1900-1910); and (3) Depreciation (1910-1915). The Corps begins ambitiously in the 1890’s, removing or cutting up thousands of obstructions from the river as listed in an 1892 report:<br /> <table border="0" align="center" cellpadding="5" cellspacing="5"><tr><td>Overhanging trees felled and cut up</td><td> 4500</td></tr> <tr><td>Number of cuts</td><td>5000</td></tr> <tr><td>Overhanging trees trimmed</td><td>1500</td></tr> <tr><td>Logs on bank cut up</td><td>6000</td></tr></table><br /> The Corps then gradually realized the scope of the task and the dynamic realities of the Chickasawhay at the turn of the century and adjectives such as "troublesome" and "dangerous" began to be used. Also at this point, USACE redefined the stream reach to be improved and the new section for improvement coincidentally corresponded with the reach they had already cleaned—the project was pronounced "complete." All subsequent activity to ~1910 was related to channel maintenance, and it was acknowledged that if maintenance ceased, the stream would quickly return to its original condition. During the early 1910’s, USACE begins to "retreat" and in 1915, presented two arguments to justify the project’s suspension: (1) "No protest against obstruction of the river has ever been received"; and (2) the stream is "commercially unimportant, useful only for logging and rafting." The Chickasawhay was then declared "unworthy of improvement by the United States" and all future expenditures ceased. So after 25 years, that was that. And now almost a century later, the Chickasawhay is again under the spotlight. But if history is any guide, she is not likely to surrender without a fight.
Effect of Land Cover Boundaries on Warm-Season Precipitation Generation in Northwest Mississippi
Year: Authors: Dyer J.
Agricultural production in the Mississippi Delta is critically dependent on precipitation; however, warm-season rainfall patterns within northwest Mississippi show that the Mississippi Delta receives a minimum of precipitation relative to adjacent regions. The reasons for this may be associated with gradients in heat and moisture fluxes along the eastern periphery of the Mississippi Delta arising from sharp changes in land cover. Using high spatial resolution simulations from the Weather Research and Forecasting (WRF) model, atmospheric patterns associated with defined non-frontal warm-season convective precipitation events are analyzed to determine the conditions related to rainfall modification in northwest Mississippi. Results show that decreased latent heat flux over the cultivated Mississippi Delta relative to adjacent forested land leads to an increase in localized lower atmospheric temperature. Combined with low-level moisture advection from the Gulf of Mexico, localized convection along the edge of the temperature gradient leads to precipitation generation and subsequent rainfall. Due to climatologically prevalent westerly flow over the region, this rainfall reaches the surface east of the Mississippi Delta. This defined pattern indicates that there is a potential for inter-basin water transport through atmospheric processes, leading to a decrease in precipitation over the Mississippi Delta due to local land cover characteristics. Future research on the quantification of the depth of water associated with atmospheric transport of moisture is imperative to defining regional water resource patterns in northwest Mississippi.
Submerged Aquatic Vegetation Communities of Mississippi Coastal River Systems
Year: Authors: Garner J.A., Cho H.J., Biber P.
Coastal submerged aquatic vegetation (SAV) abundance has declined globally due to the cumulative effects of habitat alteration and declines in coastal environment quality. There are several water quality/environmental models for seagrass/SAV habitat requirements; these models were developed based on long-term monitoring data. Application of those models by resource managers also requires extensive/consistent water quality monitoring data, hence, limiting their usages to the areas with well monitored habitats. It is necessary to develop habitat indices that can be widely used to predict SAV type/distribution in varying locations and habitat/basin types. In order to develop a Habitat Suitability Index (HSI) for SAV via a decision-tree algorithm approach that utilizes landscape properties, SAV communities of shallow waters in channels, adjoining bayous, streams, inlets, and lagoons of the Pascagoula River, Back Bay of Biloxi, St. Louis Bay, and Pearl River systems of coastal Mississippi were surveyed from May 2008 to Jun 2010. The location and species of SAV and the nearby floating aquatic and shore emergent plants were recorded. The survey extended from the river mouth to upstream areas where stream width became narrow and shade from tall trees on the shore restricted SAV growth. Survey methods included raking from a boat and wading in the water, after SAV were observed to occur in a given location. In addition to SAV species and bed location, dominant shore vegetation and GPS coordinates were recorded using a Trimble™ GeoXH handheld GPS unit and TerraSync™ software. After we develop a tree-based algorithm for the index, its validation will be assessed using a separate set of field data. Application of the index will not be restricted to the well-protected and monitored areas because the index will use geographic, topographic, and shore vegetation parameters. The resultant HSI can be used to visualize potential SAV bed locations and to predict how coastal landscape alteration would affect their distribution and abundance.
Sediment, Particulate Organic Carbon, and Particulate Nitrogen Transport in Ephemeral and Perennial Streams of the Upper Coastal Plain Mississippi
Year: Authors: Hatten J., Dewey J., Mangum C., Choi B., Brasher D.
The discharge of particulate organic carbon (POC) and particulate nitrogen (PN) from watersheds can be important in terms of carbon and nitrogen cycling and can also carry information about the process of erosion and sediment transport within the watershed. This paper will address the transport processes of POC, PN, and total suspended solids (TSS) during high discharge events in four ephemeral streams and a perennial stream of a small managed-forest. For this study, a 30 ha watershed located approximately 8 miles west of Eupora in Webster County, MS was monitored for water discharge, TSS, POC, and PN. These constituents were measured in 4 ephemeral streams and in one downstream perennial stream location. We assessed the %POC, %PN, and C/N of TSS across a range of discharges during large storm events. Preliminary results suggest that %POC and %PN may have an inverse relationship with TSS and discharge in all watersheds at all scales. The relationship between %POC, %PN, and C/N and discharge and TSS appeared to be different between the ephemeral and perennial streams suggesting that the process of sediment transport are different at each scale. These results point toward a need for a better understanding of sediment transport in managed watersheds and that the organic matter characteristics of TSS can play a strong role in this understanding.
Molecular Identification of Bacterial Communities Associated with Biodegradation of Pentachlorophenol in Groundwater
Year: Authors: Prewitt M.L., Borazjani H., Diehl S.V.
Pentachlorophenol (PCP) is a toxic and recalcitrant compound used predominately as a wood preservative to protect wood from decay caused by insects and microorganisms. Past storage, treatment and disposal practices of PCP have resulted in groundwater contamination near wood treating sites in Mississippi and nationwide. Because of PCP’s recalcitrant nature and toxicity, it has been listed as a priority pollutant by the Environmental Protection Agency. Methods to remediate PCP in groundwater include pump and treat, filtration, and biosparging. Of these methods biosparging is the only in-situ method which substantially should reduce the remediation costs. Biosparging forces clean air under the groundwater table stimulating the indigenous microorganisms to degrade the pollutant. In this study eight biosparging wells were installed at a wood treating site in central Mississippi with contaminated groundwater. Two wells (#14 and #44) were located above and 6 wells (#42, #52, #43, #51, #41 and #17) were located beneath the air sparging lines. Water samples were collected quarterly for nutrient analysis, PCP concentration and microbial identification. In addition water samples were also collected monthly before and after nutrient amendment for microbial enumerations. Nutrients added were nitrogen, phosphorus, and potassium. After nutrient addition the largest increase in nutrient levels occurred for nitrogen and ortho-phosphorus in well numbers 52 and 17 both located near and far respectfully below the air sparging lines. Wells 52 and 17 also showed greater changes in Total Organic Phosphorus (TOP), Total Organic Carbon (TOC) and chloride ion (Cl<sup>-</sup>) over time than the other wells. Total bacteria and PCP tolerant bacteria were highest in well # 14 located slightly above the sparge lines after eight monthly nutrient additions. PCP concentrations varied during the sampling period but did not decrease. Identification of PCP tolerant bacteria based on molecular methods revealed 17 bacterial species of which two were known PCP degraders, <em>Burkholderia cepacia</em> and <em>Flavobacterium</em> sp.
Automated system to facilitate vicarious calibration of ocean color sensors
Year: Authors: Lawson A., Arnone R.A., Gould R.W., Scardino T.L., Martinolich P., Ladner S.W., Lewis D.
For calibration and validation, satellite products are often compared against in situ measurements. Over time, the satellite-measured data drift due to sensor degradation, resulting in errors of unknown magnitude: comparison against ground truth data allows the satellite sensor to be recalibrated. This process is known as vicarious calibration because pre-launch sensor calibration information can be adjusted once the complete system is operational in space. It is an essential component for any long-term satellite operation in order to ensure optimal accuracy in the satellite-derived products. We have developed an automated, continuous vicarious calibration system for satellite ocean color sensors (MODIS, MERIS, SeaWiFS) that employs a website interface to extract and visualize both satellite and in situ data. The data are graphed over time to allow instant visual comparison between the satellite sensor and the in situ data points and to help detect trends (drift) in the satellite measurements. In this case ,we are using the NASA Aeronet-OC sites, including those in the Northern Adriatic, Martha’s Vineyard, and the Gulf of Mexico. In addition, we are using multiple satellite resolutions to assess within pixel variation to allow further fine-tuning of the calibration factors and a better understanding of how the remote sensing data relates to the in situ truth. Various products are analyzed in the comparisons including the water-leaving radiance, remote sensing reflectance, chlorophyll concentration, and absorption, scattering, and backscattering coefficients. Because of the signal loss to atmosphere and water absorption of light with remote sensing, we consider two box sizes around the center satellite pixel that covers the Aeronet sites: a five-by-five box and a three-by-three box. Upon ingestion into our database various statistics are compiled on the data, including the standard deviation within the box, the mean, and the minimum and maximum values. These are used to generate error bars both spatially and temporally and detect outliers. With these statistics compiled daily and graphed in a time series format at daily, monthly, and yearly intervals, we are better able to understand sensors degradation through time and the impact on data retrievals; deviations between sensor-derived values and in situ measurements; the impact of varying sensor resolutions; and intercomparison of multiple sensors.
Identification of Pentachlorophenol (PCP) Tolerant Bacterial Communities in Contaminated Groundwater After Air-Sparging Remediation
Year: Authors: Stokes C.E., Prewitt M.L., Borazjani H.
Pentachlorophenol (PCP), a highly toxic and recalcitrant wood preservative, contaminates groundwater aquifers in many areas of the United States. Improper handling, storage, and disposal practices in the past have led to the contamination of groundwater at many wood treatment facilities. Air sparging, the injection of clean air under pressure into the groundwater system, has emerged as a viable in-situ treatment option for removal of this type of contamination. Previous studies have relied on morphological studies for identification of the bacterial community that is responsible for PCP degradation. However, molecular identification of DNA extracted from the bacterial community present in the groundwater will provide a more accurate description of the microbial community. Groundwater samples from eight biosparging wells were taken quarterly and analyzed for total PCP concentration, nutrient content, and monthly samples were used for microbial identification. Microbial counts were taken for each well on selective media, and changes over time were compared between wells within the sparging wells’ zone of influence and wells not directly impacted by air sparging. PCP concentration was below 1 ppb and nutrient levels were within the normal range. Well 14 (above air injection) revealed <em>Burkholderia</em> sp., <em>Denitratisoma oestradiolicum</em>, <em>Thauera</em> sp., and <em>Rhodoanobacter thiooxydans</em>, along with >40 other species that were listed as "e;uncultured" in BLAST. Well 51 (below air injection), presented a greater variety of bacterial species than Well 14, including the known PCP degrader <em>Flavobacterium</em>, in addition to numerous "uncultured" species. DNA extracted from other wells is currently being sequenced and T-RFLP analysis is underway to provide a comparison over time of microbial communities between aerated and non aerated wells.
Delta Headwaters Project—Boon or Bust to Water Quality?
Year: Authors: Johnson D.R.
The Delta Headwaters Project (DHP-formerly Demonstration Erosion Control Project) was initiated by Congress in 1984 in six Yazoo Basin headwater streams. The project has since been expanded into sixteen watersheds, which encompass over 6,800 square kilometers. DHP seeks to develop and demonstrate a watershed systems approach to address problems associated with watershed instability including: erosion, sedimentation, flooding and environmental degradation. DHP provides for the development of a system for control of sediment, erosion and flooding in the hill areas of the Yazoo River Basin, Mississippi. The project uses a variety of features for sediment control, which include: riser pipes, bank stabilization, and grade control structures. This study uses daily suspended sediment and discharge measurements from 16 sites to evaluate the effectiveness of DHP with regard to sediment control. The annual sum of these two parameters were calculated and compared by site. Most sites displayed a large decrease in the sum suspended solids over the life of the project. The ratio of the sum of suspended solids to discharge was also calculated. This ratio was used to adjust the suspended sediment changes with discharge. Again most sites displayed large decreases in this ratio over time. Hotopha Creek had a sediment:discharge ratio of 3.7 in 1987, which was reduced to 1.4 in 1997. This produced a reduction in the average daily sediment load from 111 tons/day in 1986 to 44 tons/day in 1997 under similar hydrologic conditions.
Using lake sedimentation rates to quantify the effectiveness of past erosion control in watersheds
Year: Authors: Wren D.G., Davidson G.R.
The effectiveness of erosion control measures is difficult to quantify, hampering the development of management practices and preventing accurate assessment of the value of erosion control structures over time. Surface erosion can vary widely over an area, particularly if gully erosion is present, and the use of sediments transported in streams for quantifying erosion is hindered by the highly variable nature of fluvial sediment loads. When a watershed drains into a lake, accumulated sediments have the potential to yield information about historic rates of sedimentation that can be used to evaluate the effectiveness of previous erosion control measures. In the present study, sediments from five natural oxbow cutoff lakes (Beasley, Washington, Wolf, Roundaway, Moon) in the Mississippi River alluvial floodplain were dated using <sup>210</sup>Pb decay rates and bomb-pulse derived <sup>137</sup>Cs with the goal of relating trends in sedimentation rate to reductions in erosion due to management practices. It was found that the radioisotope dating methods were best used in concert with known dates for implementation of management practices. Changes in sedimentation rate over time frames as short as 15 years were detectable. Larger lakes generally showed smaller changes in sedimentation rate as may be expected because of the expense and difficulty in applying management practices over larger areas.
The Sustainable Sites Initiative™: Potential Impacts for Water Resources and Site Development
Year: Authors: Brzuszek R.F.
The Sustainable Sites Initiative (SITES™) is a new national effort to create voluntary guidelines and benchmarks that promote sustainable land design and construction practices. Jointly sponsored by the American Society of Landscape Architects, the Lady Bird Johnson Wildflower Center, and the U.S. Botanic Garden; SITES™ provides a ranking system that awards points for comprehensive sustainable land practices for built projects. The program is complementary to LEED ® (Leadership in Energy and Environmental Design) Green Building Rating System, and it is anticipated that the SITES™ points will be incorporated into future versions of LEED ®.<br /><br /> SITES™ has five areas of focus—hydrology, soils, vegetation, materials, and human health and wellbeing. The program promotes examples of sustainable practices and awards up to 250 possible points for a project. A maximum of 44 possible points can be awarded for water practices. Credits are given for the following activities that protect and restore the processes and systems for a site’s hydrology: <ul><li>Reduce potable water use for landscape irrigation</li> <li>Protect and restore riparian, wetland, and shoreline buffers</li> <li>Rehabilitate lost streams, wetlands, and shorelines</li> <li>Manage stormwater on site</li> <li>Protect and enhance on-site water resources and receiving water quality</li> <li>Design rainwater/stormwater features to provide a landscape amenity</li> <li>Maintain water features to conserve water and other resources</li></ul> This presentation will provide an overview of the Sustainable Sites Initiative with a focus upon how the program will protect water quality in developed projects. Implications and incentives for planners, landscape architects, engineers, developers, builders and other professionals in the state of Mississippi to take part in the program will be discussed.
Flash Flood Guidance issued by the National Weather Service-Past, Present, Future
Year: Authors: Costanza K.E.
Flash flooding is a serious threat that accounts for the largest number of weather related deaths per year in the United States. The National Weather Service realized the severity of this threat during the Independence Day flooding event of 1969 which killed 41 people over a few counties in Ohio. That event sparked the National Weather Service to begin issuing some form of flash flood guidance that could effectively warn communities of potential flash flooding risks associated with a rain event. Over the years, the models for determining the flash flood guidance values have evolved from simple "rules of thumb" to a more scientific basis. <br /><br /> The current model, the Gridded Flash Flood Model (GFFG), used to determine flash flood guidance is based on a 4km by 4km grid scale and uses the National Resources Conservation Service (NRCS) Curve Number methodology. This method was chosen because of its ability to take into account the antecedent soil moisture conditions of a system, calculate the abstractive losses based on a Curve number, and calculate a peak flow by way of the Triangular Unit Hydrograph method. The determination of the antecedent soil moisture conditions are determined by a distributed hydrological model and relayed to the GFFG Model. The NRCS Curve Number method is also appealing because it can be tied to the physical world through the determination of a curve number which can take into account the spatial variability of soils types, vegetative cover and slope of a watershed. The final guidance of the model is varying rainfall amounts associated with the appropriate temporal scales (1, 3, 6, 12 and 24 hour) likely to cause flooding for an area. <br /><br /> Due to the serious nature of flash flooding, the need for improvement to the current model is imperative. Although the current model is a drastic improvement relative to the past models, there is still room for further improvement. One example would be incorporating finer spatial resolution data, such as soil data, to determine new Curve Numbers used in the model. With current GIS applications, the incorporation of this type of data is relatively simple. Other more advanced improvements could include evaluating different infiltration models to determine the abstractive losses of the system. The methods used in the current model are strictly empirical and the use of more physically based infiltration models could produce better results. In addition, the current model lacks connectivity between grid cells which could cause issue if there is a rain event upstream of a "problem cell". This connectivity could be gained by routing flow from one cell to another. Continued scrutiny of the current model will only yield improved guidance issued to communities resulting in more credibility of products rendered by the National Weather Service.
New Modeling System at the Lower Mississippi River Forecast Center
Year: Authors: Roth K.
The Lower Mississippi River Forecast Center (LMRFC) uses the National Weather Service River Forecast System (NWSRFS). This system includes a variety of hydraulic and hydrologic techniques and operations that handle everything from the initial processing of historical data to the preparation of river forecasts. At the time of development (1971) NWSRFS was run on a mainframe computer and the code was streamlined to function with the limited computer resources of the day. Computer hardware and software development architecture have advanced in the last 40 years so that much of the NWSRFS functionality is no longer necessary. NWSRFS requires a large amount of maintenance and is no longer cost effective to keep it in service.<br /><br /> In 1997, the Office of Hydrologic Development (OHD) and a team of hydrologists began the process of investigating solutions for the aging NWSRFS. After much research and testing of software, FEWS (Flood Early Warning System), developed and maintained by the Dutch Company, Deltares, was chosen as the replacement for NWSRFS. The FEWS software is platform independent and offers a service oriented architecture that is modular in a sense like NWSRFS, but lent itself to more readily incorporating new modules and techniques. The FEWS software communicates with the hydrologic/hydraulic models and modules using a standard XML based protocol for which an adapter can be developed to pass information to and from and execute. To make it usable for the River Forecast Centers, FEWS adapters were developed to use many of the existing hydrologic operations, techniques, and models from NWSRFS. The Community Hydrologic Prediction System (CHPS) became the NWS’s customized application of FEWS. CHPS runs models that are compatible with FEWS including those migrated from NWSRFS. <br /><br /> Currently CHPS is installed at the LMRFC but is not fully operational. To make it operational, the staff is migrating all of the hydrologic data necessary, to make a forecast, from NWSRFS to CHPS. This process is largely done automatically by scripts but some local customization is necessary. Once the migration to CHPS is complete and the model is running and stable, the LMRFC will begin parallel operations where we will produce forecasts using NWSRFS and CHPS. These forecasts will then be compared to verify that similar results are being achieved. After a period of evaluation, NWSRFS will be retired and CHPS will be the operational forecast system used at the LMRFC.
Sea Level Rise Visualization on the Alabama-Mississippi and Delaware Coastlines
Year: Authors: Wilson K.V., Turnipseed D.P., Thatcher C., Sempier S., Wilson S.A., Mason Jr. R.R., Marcy D., Burkett V.R.
Coastal communities throughout the U.S. are in the initial stages of thinking about, planning, and/or creating climate adaptation plans. Emergency managers, developers, and the general public need to know the potential impact of a rising sea level and how that phenomenon may influence plans for developing future critical infrastructure and for habitat restoration and conservation. <br /><br /> In late 2008, in response to these critical needs, the U.S. Geological Survey and the National Oceanic and Atmospheric Administration in concert with the Mississippi-Alabama Sea Grant Consortium, the Delaware Department of Natural Resources and Environmental Control and several other Federal, State, and local stakeholders formed a team to create two pilot internet map applications that could effectively project various sea level rise scenarios on the Alabama-Mississippi Gulf of Mexico Coast and the mouth of the Christina River and Upper Delaware Bay at Wilmington, Delaware. <br /><br /> The Alabama-Mississippi Gulf of Mexico Coastal pilot Internet Map Server was developed from an existing server which was built principally to display the maximum storm tide crest resulting from Hurricane Katrina (2005). This server quickly and easily projects 1-, 3-, and 6-ft sea level rises onto a 3-meter digital elevation model constructed from Light Detection and Ranging (LiDAR) data procured before Hurricane Katrina. <br /><br /> The Delaware River pilot , developed with a similar concept, used a 2-meter horizontal Digital Elevation Model created from State of Delaware LiDAR data to illustrate a hypothetical 4 ft. rise in sea level. Flood frequency estimates were computed based on National Weather Service coastal flood warning criteria to show how these increases in sea level could make daily tidal flooding worse.
Phytoplankton Biomass Variability in a Western Mississippi Sound Time-Series
Year: Authors: Dornback M., Lohrenz S.
This study is observing the temporal and spatial fluctuations in phytoplankton biomass in the water column in relation to light availability, nutrients, and environmental factors such as salinity and temperature. The focus will be on what factors promote changes in phytoplankton biomass above and below the stratified layer and in a mixed water column. This is particularly important because harmful algal blooms and summertime hypoxia are both linked to water column stratification. <br /><br /> Monthly cruises (9/07-Present) are conducted to collect the samples. Optical instruments are used to measure <em>in situ</em> light absorption (ac-9), attenuation (ac-9), and backscatter (bb-9) in nine different wavelengths. Phytoplankton biomass is measured through the proxy of <em>in situ</em> chlorophyll <em>a</em> (chl <em>a</em>) fluorescence intensity using a FL-3. A CTD is used for measurements of salinity (converted from conductivity), temperature, and depth. <br /><br /> Water samples from the start, middle and end of the transect are collected at multiple depths and returned to the lab for analysis of nutrients (N, P, Si), chromophoric dissolved organic matter absorption, the pigmented and non-pigmented absorption fractions of suspended particulate matter and the bulk mass of the suspended particulate matter. <br /><br /> The western Mississippi Sound is a vital economic and ecological resource to the surrounding region. A large percentage of coastal residents between Bay St. Louis and Biloxi and rely on the Sound for revenue from tourism and fisheries. The water quality of fishery habitats and nurseries can greatly affect fauna health and the health of human consumers. It is important for coastal water quality to be properly assessed in order to understand the threats to the local ecosystem and to mitigate any anthropogenic causes. <br /><br /> Preliminary results show fluctuations in chlorophyll a abundance through the months and between sampling stations on a single month. Distinct phytoplankton blooms are detected above and below the pycnocline. More analysis of the water column properties will need to be conducted to understand the reason between the fluctuations. <br /><br /> In addition, major environmental disturbances such as hurricanes (Gustav 9/1/08-9/2/08, Ida 11/9/09-11/10/09) and the Bonnet Carre Spillway opening (4/11/08-5/12/08) have been detected in the monthly optical profiles. Further analysis of the data will have to be conducted to see if any anomalies are detected due to the Deepwater Horizon oil spill.
The Future of K-12 Water Education: The 2010 Mississippi Framework and the Proposed National Research Council Framework for Science Education
Year: Authors: Clary R.M., Brzuszek R.F., Wandersee J.H.
Previous researchers (Brzuszek et al 2009) investigated the role of non-governmental organizations (NGOs) in four northern Gulf Coast watersheds (Alabama, Florida, Louisiana, and Mississippi), and reported that the NGOs’ focus varied by watershed. However, subsequent analysis of these northern Gulf States’ educational standards revealed that the NGOs’ focus was not being reflected in the respective state’s water education requirements (Clary & Brzuszek 2009). Under the 2001 Mississippi Science Framework, 69% of the researchers’ 13 identified water topics were included, but most of these were non-required objectives, or within elective courses that are not taught at all Mississippi schools. Only one topic, pollution, was required to be taught as a state competency (grade 4). While Louisiana fared better than other coastal states with 54% of the water content topics in K-12 education, several topics were still omitted. Clary and Brzuszek (2009) concluded that greater collaboration was needed between watersheds, their associated NGOs, and educators to implement water education in public schools through the required science content standards. <br /><br /> However, science education is not static: Both the 2010-11 adoption of Mississippi’s 2010 Science Framework and the recently released 2010 National Research Council (NRC) draft of the conceptual Framework for Science Education indicate that new challenges and opportunities exist for water education. Our current research compared water education topics in the Mississippi 2010 Science Framework against the earlier 2001 Framework. While there is greater vertical alignment between grades K-8 in the 2010 Framework, many of the water topics are included as optional objectives and not as required competencies, resulting in increased water education <em>possibilities</em> with teacher flexibility. Content analysis of the preliminary public draft of the NRC science framework also revealed flexibility and water education potential: Although water education was not regularly mentioned in the document, the new NRC draft focuses upon "learning progression." Another notable change is the incorporation of Engineering and Technology as a fourth domain of science alongside the current domains (Life, Earth and Space, and Physical sciences). <br /><br /> Both Mississippi ’s vertical alignment and the NRC learning progressions are consistent with our best practices model (Clary & Brzuszek 2009). These documents also suggest a potential educational trend toward increased content reinforcement across grade levels and teacher flexibility. We suggest there may be increased opportunity for NGOs to develop water education programs at multiple grade levels that address these broader science standards, resulting in greater inclusion of water education within the local watershed.
Total suspended sediment concentrations in Wolf Lake, Mississippi: an EPA 319 (h) landscape improvement project
Year: Authors: Kroger R., Brandt J.R., Fleming J.P., Huenemann T., Stubbs T., Prevost J.D., Littlejohn K.A., Pierce S.
The Wolf - Broad Lake water body (13 km in length) was evaluated as impaired and included on the Mississippi 303(d) list of impaired water bodies. As such, the EPA 319 (h) program, through the Mississippi Department of Environmental Quality selected this water body and its associated watershed for landscape improvement, with the goal of moving towards improving the lakes water quality, meeting associated evaluated total maximum daily loads, and ultimately de-listing the water body for total suspended sediment (TSS) impairment. A study was undertaken for 2 years to evaluate and document appropriate changes to the total suspended sediment loads (mg/L) and overall lake turbidity. These two objectives were analyzed with monthly surface sampling events of turbidity using automated sampling technology (Eureka - Manta 2, Automated Data-son) as well as 20 random samples per sampling trip for TSS analysis. Results from a non-parametric Kruskal-Wallis analysis indicate a significant month-by-year effect on turbidity and TSS (Chi-square = 76.08, <em>P</em> = 0.001), but reach (Chi-square = 2.45, <em>P</em> = 0.784) and depth by reach (Chi-square = 2.44, <em>P</em> = 0.784) did not show significant effects on turbidity. There were no significant correlations between TSS and turbidity concentrations and two day, and seven day summed or mean rainfall. Spearman correlation analysis for TSS indicated significant correlations between TSS and mean two day (r<sup>2</sup>= 0.62, <em>P</eM>= 0.002) and seven day (r<sup>2</sup>= 0.51, <em>P</em>= 0.014) wind speeds. All other variables used in the analysis did not show significant correlation with TSS (<em>P</em>> 0.05). This suggests that wind conditions, rather than rainfall predict the greatest variability in TSS and turbidity in Wolf Lake. These documented correlations between lake water column TSS and turbidity, and wind highlight the difficulties of demonstrating success in a short temporal period between project initiation and completion. Unmanageable environmental conditions (wind speed and direction), and limited temporal monitoring scales (1.5 years post BMP implementation) limit the possibility of demonstrating success of water quality improvement within Wolf Lake a 303(d) listed water body.
Spatial and temporal changes in nutrients and water quality parameters in four Puerto Rico reservoirs: implications for reservoir productivity and spo
Year: Authors: Kroger R., Neal J.W., Munoz M.
Water quality of reservoirs is the foundation of the ecological cascade that results in productive fisheries. The current study evaluated four tropical reservoirs (Dos Bocas, Cerrillos, Guajataca, and Lucchetti) in Puerto Rico for spatial and temporal dynamics in water quality parameters to better understand effects on bait fish and subsequently largemouth bass sport fisheries. Surface mapping, and depth profiles of in situ parameters of dissolved oxygen, pH, temperature and turbidity using an automated flow through Eureka Manta data-son yielded distinct differences between reservoirs in space and time. Several limnological phenomenon were observed within this dataset including distinct influence of river inputs into reservoirs, the prevalence of irradiance avoidance, and substantial and significant oxyclines with depth at varying times of the year. These spatial variations in water quality variables result in direct implications for resource availability. Nutrient concentration ranges were significantly different between reservoirs (F = 6.45; P < 0.05) and were attributed to varying degrees of land use in the respective upland catchments (Dos Bocas NO3-N: 0.8 mg/L; Guajataca NO<sub>3</sub>-N: 0.04 mg/L). Nutrient concentrations were low in all reservoirs, with certain reservoirs (Cerrillos and Guajataca) being classified as oligotrophic. Although no direct correlations can be made to fish production, it is important to understand limits to resource production within these systems. Dissolved oxygen, pH, water temperature and nutrient concentrations all work in unison to provide a bottom-up controlled aquatic system that sustains phytoplankton production, baitfish and subsequently sports fisheries.
Evaluation of the Estuarine Retention Time in a Mississippi Estuary: The Bay of St. Louis
Year: Authors: Camacho R.A., Martin J.L.
The Estuarine Residence Time (ERT) is an important hydrodynamic-water quality parameter that evaluates the amount of time a substance remains in an estuary. The water quality of estuarine systems is often closely linked to the ERT. For example, estuarine systems with a low ERT are less vulnerable to algae blooms than estuarine systems with a higher ERT. Also, this parameter can be used to assess the characteristics of the transport of contaminants within estuaries as well as to evaluate the auto-depurative (self-cleansing) capacity of these systems. <br /><br /> This paper presents the results of an initial analysis of the ERT of the St Louis Bay Estuary, MS, using the linked hydrodynamic and water quality models EFDC and WASP. The computation of the ERT is based on the method described by Miller and McPherson as computed by the time required to reduce the concentration of a conservative constituent to some percent of its original concentration. For the analysis, an initial dye concentration was set to 100 units within the system, with all boundary conditions set to zero, and the models run until the dye concentration was less than 1 percent of the original value (a value of 10 percent remaining is usually used to estimate the ERT). The ERT was also evaluated using water age, a state variable in EFDC. Low and high hydrologic conditions were estimated for the inflows of the system using the information developed by previous studies to evaluate the response of the system. Results suggest that the estuary is characterized by a relatively low ERT and demonstrated that the use of a hydrodynamic model as EFDC is an effective means to evaluate the ERT in an estuary.
Detecting Water Quality Parameters in Tibbee Creek, Mississippi Using Aerial Imagery
Year: Authors: Irvin S., Paz J.O., Tagert M.L., Parajuli P., Cathcart T.
Assessing water quality on impaired streams helps determine the magnitude of its impairment and identify the exact location where the impairment is most severe. Advances in remote sensing and geospatial technology have allowed researchers and environmental agencies to assess streams by monitoring large areas. Using both <em>in situ</em> measurements and aerial imagery and comparing the differences can provide a more specific view on the streams health. The main goal of this study was to demonstrate the use of aerial imagery in detecting water quality indicators in impaired streams. A 3-mile segment of Tibbee Creek in Clay County, Mississippi, an impaired water body listed on the Mississippi 303(d), was selected for this study. Water samples were collected at different points along the river, with transects at each point between May and July 2010. The temperature differences and dissolved oxygen levels were measured at each transect. Samples were tested for turbidity, total suspended solids (TSS) and biological oxygen demand (BOD5). High resolution (0.5 m) aerial images that covered the entire study area were obtained in order to capture spatial differences along the channel. Preliminary analysis shows that turbidity readings were higher in the downstream segment of the river during the early part of testing and toward the end of testing. This was not the case during the middle of the summer and after rain events. Relationships between spectral bands and observed water quality parameters were used to estimate the water quality parameters at different locations of Tibbee Creek. The results of this research are expected to assist in the development of near real-time maps for the evaluation and monitoring of water quality of streams and rivers, providing large spatial coverage resulting in significant cost-savings over conventional <em>in situ</em> water quality.
Three-dimensional Heterogeneity of Hypoxic Water Masses in the Mississippi Sound: The Geomorphology Connection
Year: Authors: Milroy S.P., Moshogianis A.
Seasonal hypoxia is certainly common over the Louisiana-Texas (LATEX) shelf west of the Balize Delta, but over the last several years summer hypoxia has also been discovered east of the delta in the Mississippi Bight (Dillon et al. 2008, Brunner et al. 2009) and in the deeper reaches of the Mississippi Sound (Gundersen, pers. comm.). Hypoxia most commonly occurs during times of significant vertical stratification of the water column, caused by the complimentary effects of seasonal heating and freshwater discharge. These discharges, when laden with organic and inorganic nutrients, further exacerbate the geographic extent of these hypoxic water masses. While the causative agents of coastal hypoxia have been well-described, the synergies between coastal geomorphology and the net ecological burden (O<sub>2</sub> production <em>v</em>. respiration) within the Mississippi Sound/Bight are less well-known. Over a series of cruises conducted from 01 APR–30 JUL 2010, vertical profiles from thirty repeat stations within a highly resolved (25 km<sup>2</sup>) grid were analyzed monthly for <em>in situ</em> CDOM/phycoerythrin/chl-<em>a</em> fluorescence, temperature, salinity, and dissolved oxygen. Results indicate that differences between surface and near-bottom chl-<em>a</em>, coupled with the unique geomorphology of the Mississippi Sound/Bight, can produce hypoxic water masses with significant heterogeneity over fine spatial scales.
Adaptation to Rainfall Variation Considering Climate Change for the Planning and Design of Urban Stormwater Drainage Networks
Year: Authors: Mamo T.G.
Climate change is a reality that planners and designers of drainage infrastructures must consider. The cumulative effects of gradual changes in hydrology due to climatic change are expected to alter the magnitude and frequency of peak flows over the service life of urban stormwater networks. Potential future changes in rainfall intensity are expected to alter the level of service of urban storm water networks, with increased rainfall intensity likely resulting in more frequent flooding of storm and surcharging of culverts. <br /><br /> The expected effects of climate change necessitate a change in the approach used to plan for and design urban stormwater networks. New development should ideally be served by both a minor storm drainage system, such as a traditional storm drainage system, and a major overland storm drainage system designed to convey the excess runoff when the capacity of the minor system is exceeded. <br /><br /> The planning and design of new urban stormwater networks should incorporate development features and sustainable urban drainage systems that provide multiple benefits such as a reduction of localized urban flooding and harmful environmental impacts, so the future urban stormwater networks design may be subject to a future rainfall regime that differs from current design standards.
Developing a Gum Swamp Educational Exhibit at the Crosby Arboretum, Mississippi State University Extension
Year: Authors: Brzuszek R.F., Schauwecker T.J.
The mission of the Crosby Arboretum, Mississippi State University Extension (located in Picayune, MS) is to preserve, protect, and display plants and their communities in the Pearl River Drainage Basin. The Crosby Arboretum’s nationally award-winning master plan has designated a portion of its facility for the creation of a gum swamp educational exhibit. Gum swamp forests are semi-permanently flooded forests that are predominated in species type and frequency by black gum (<em>Nyssa biflora</em>) and tupelo gum (<em>Nyssa aquatica</em>). As specified in Mississippi’s Comprehensive Wildlife Conservation Strategy by the Mississippi Department of Wildlife and Fisheries (MDWF), Bald Cypress/Gum Swamp Forest Communities are considered vulnerable in the state of Mississippi. The proposed gum pond exhibit will address MDWF priorities through the construction and management of the exhibit; as well as providing a public venue for public education and experience for this vulnerable forest type.<br /><br /> The Crosby Arboretum Foundation was awarded a grant to create .5 acres of Arboretum property for a gum pond wetland exhibit. Graduate students in the Department of Landscape Architecture at Mississippi State University utilized a semester-long class project in spring 2010 to research and design the proposed gum pond exhibit. Students conducted a literature search on gum ponds and related wetlands and visited several <em>in situ</em> natural gum swamps in Mississippi. Students recorded environmental data at the natural wetlands to inform the restoration design. Students also conducted an environmental inventory and analysis at the proposed exhibit site that recorded the site’s hydrology patterns, plant species, soils, and other data. A design charrette, or a collaborative session to determine solution to the design problem, was conducted with wetland specialists and landscape architects to develop the preliminary design. This presentation will discuss the method used to develop the exhibit design and will exhibit the drawings for the proposed gum pond. Construction for the exhibit is slated to begin in summer 2010.
Oil Spill Assessment: Transport and Fate
Year: Authors: McAnally W.H., Martin J.L., Alarcon V., Diaz-Ramirez J., Amburn P.
Oil spilled from the Deepwater Horizon incident has been reported washing ashore from Florida to Texas, affecting shoreline over thousands of km. Beyond the effects of the oil itself are those of the dispersants that have been used and the combined oil-dispersant emulsions. BP, Inc. has asked the Northern Gulf Institute (NGI) to provide research results that will, among other objectives, predict the distribution, dispersion and dilution of these contaminants under the action of currents and storms in estuaries. In response, an integrated assessment of physical and biological processes and effects of oil spills in the Gulf of Mexico is being performed by an interdisciplinary NGI team. This paper reports on the use of numerical models to examine the transport and fate of those contaminants in nearshore waters. <br /><br /> The use of mathematical models is well established, such as in the regulatory environment to estimate impacts of remediation of contaminated sediments and a variety of other purposes. Predictive water quality models are typically used to develop linkages between sources and targets. The models provide a quantitative link between sources and targets, or cause-and effect relationship, in order to determine the capacity of the waterbody to assimilate contamination and to address the site-specific nature of the problem. Models of open waters and Gulf estuaries most commonly include hydrodynamic, sediment, and water quality models, due to the importance of transport on the fate of water quality constituents. The models may then be focused on the kinetic and transformation process impacting the specific issue of concern (oil spills, etc.) in order to address specific concerns such as algal growth, hypoxia, and others. <br /><br /> The research is focusing on quickly applying available models of Gulf estuaries, demonstrating how they may be used to assess the long-term impacts of the oil spill (e.g. on hypoxia, sequestration in sediments, toxicity to algae, etc.), establishing and prioritizing remedial actions, and indentifying deficiencies in the literature impacting or introducing uncertainty into those predictions, such as kinetic rates impacting fate. Visualization and interpretation of the results is a key component of the assessment, so 2D and 3D visualization tools have been employed.
Use and Effectiveness of Natural Remediation of Wetlands at the GV Sonny Montgomery Multi-Purpose Range Complex-Heavy (MPRC-H), Camp Shelby Joint Forc
Year: Authors: Floyd I.E., Orsi T.H.
The GV Sonny Montgomery Multi-Purpose Range Complex-Heavy (MPRC-H) is a training range, located within the Camp Shelby Joint Forces Training Center (CSJFTC), MS, and is used by armored and mechanized infantry and attack helicopter units. Construction of the range occurred in 2004 during a period of low regional precipitation. Lack or inadequate installation of sediment control structures (sediment fences and matting), combined with high daily rainfall over a 2 week period, led to extensive erosion within and around the range and sediment infilling of two parts of Davis Creek basin, immediately outside the MPRC-H. The impacted areas covered over 42 wetland acres and were infill with sediment 6-14 inches thick. Thereafter, proper erosion control structures were installed and natural remediation was selected as the most viable option for site regeneration. <br /><br /> The impacted areas outside the MPRC-H have been monitored since 2005, most recently in 2009. During the 2005 assessment, the absence of small vegetation was most obvious and the event lead to dramatic increases in turbidity within the Davis Creek tributary and subsequent downstream tributaries. Interestingly, elevated turbidity levels were noted for almost 2 years after the sediment control structures had been repaired and/or replaced. During our 2009 survey, it was determined that fluvial, overland runoff processes and infill compaction within the MPRC-H wetland have led to substantial reductions in the aerial extent (39%) and thickness (30%) of the sediment plume. None-the-less, even with this significant removal of material, the remainder may or may not be removed by natural processes over timescales of human and engineering interest. However, understanding the processes that have taken place in and around the MPRC-H should form a template for future sites to determine which remediation option, anthropogenic or natural, is most cost-effective and beneficial.
Headwater Hydrologic Functions in the Upper Gulf Coastal Plain of Mississippi
Year: Authors: Choi B., Ezell A.W., Dewey J.C.
Headwater streams are often considered to be contributors of nonpoint source sediment in forested watershed areas and are a key component of overall hydrologic processes because they comprise more than 60-80% of stream networks and watershed land areas. However, the relationship between silvicultural practices in the uppermost portions of headwater systems characterized by ephemeral-flow areas and their downstream linkages is poorly understood. In Mississippi’s forestry best management practices (BMPs) manual, streamside management zones (SMZs) have specific guidelines for perennial and intermittent streams, but ephemeral streams are rarely considered in forest resources management. This study is being conducted in Webster County, Mississippi to (1) examine the influence of ephemeral-flow portions of headwaters on downstream hydrology and water quality, and (2) evaluate silvicultural BMPs effectiveness of ephemeral streams in protecting downstream water quality. Specific objectives of this study are to test effects of four levels of harvest in ephemeral-flow areas on (1) in-stream water quality and total suspended sediment (TSS), (2) surface erosion and deposition in pre- and post-harvest conditions, and (3) the responses in subsurface hydrology. This study is installed as a randomized complete block (RCB) design consisting of three replicates of four treatment watersheds (No BMP, BMP1, BMP2, No harvest) representing a range of potential BMPs for ephemeral-flow portions of headwater streams. Results consisting of one year of pre-treatment data and two years of post treatment data will be presented. This study will increase our understanding of effectiveness of the headwater BMPs in mitigating timber harvesting impacts on water quality in riparian areas as well as providing information on the relationship between hydrological connections between perennial and ephemeral streams, and overall water quality.
Recharge in the Water Budget of the Delta’s Alluvial Aquifer
Year: Authors: Mason P.
The Missisippi River Valley Alluvial Aquifer (MRVA) is a highly productive aquifer which supports vast amounts of Delta agriculture and commerce. Maintaining an adequate future water supply requires understanding of the water budget. Stated simply: current water levels + recharge - discharge = future water levels. Focusing on the recharge term in the equation, existing evidence about recharge to the MRVA is reviewed, and current active research is described.<br /><br /> Normal direct recharge by precipitation is extremely restricted in the MRVA because of a widespread impermeable unit just below the soil profile. Direct recharge is, however, active in localized areas, particularly through the conduit of the alluvial fans along the eastern boundary of the Delta plain. An estimated 220 square miles of land surface is covered by fans, with vertical relief ranging from 4 to 66 feet. Drilling reveals much greater thicknesses of alluvial fan deposits occur below the surface, coeval with deposition of the MRVA. <br /><br /> Recharge from streams is also a significant factor in the bluff margin area, where streams cross fan sediments which lie in connection with the MRVA. In summer, many smaller streams can be observed to lose flow and disappear as they traverse fans. Direct discharge measurements of larger streams have recorded every condition as streams cross the fans, from gains on clay dominated fans, to significant losses over sandy materials, suggesting that the variable source geology of the reworked sediment making up each fan tends to control the amount of gain or loss of flow from any given stream to the aquifer. <br /><br /> Efforts are underway to characterize and quantify water heads and pathways along the Bluff Hills boundary for use in a large flow model. These include data collection regarding the size and hydraulic conductivity of the alluvial fans, the role of Yazoo headwater streams and other surface watersheds, and the involvement of the several geologic formations adjacent to the MRVA.
Water Quality Assessment in the Town Creek Watershed, Mississippi
Year: Authors: Ortega-Achury S.L., Ramirez-Avila J.J., McAnally W.H., Martin J.L.
Surface water quality is deteriorating around the world at an increasingly alarming pace. The majority of the incidences from nutrient impacts are primarily occurring in areas with increased development. Town Creek Watershed is located within the Tombigbee River Basin representing 50% of the Upper Basin and is approximately 10% of the entire Tennessee-Tombigbee Waterway Watershed. Town Creek watershed directly contributes to the Aberdeen pool on the Tennessee-Tombigbee Waterway. Data relating sediment and nutrients concentrations and discharges after 1994 are not available for most of the watersheds within the Tombigbee River Basin. The objective of this study is to provide valuable water quality data for the upper Tombigbee Watershed. The study area included four of the five sub-basins within Town Creek that according to the EPA and MDEQ are biologically impaired due to sediment and nutrients. The study monitored the water quality conditions in the major tributaries of Town Creek Watershed. Grab samples and <i>in situ</i> measurements of water quality parameters (dissolved oxygen (DO), temperature (T), electric conductivity (EC), turbidity, and pH were taken at 24 stations with 7 along the principal channel within the study area. The collected water samples were analyzed for total phosphorus (TP), dissolved reactive phosphorus (DP), and suspended sediment concentration (SSC). Preliminary results for the monitoring period of May 2008 to February 2009 showed mean values for T, pH and EC of 23 °C, 8, and 343 mS cm<sup>-1</sup>, respectively. DO concentrations and turbidity levels showed mean values of 6.4 ppm and 14 NTU, respectively. Phosphorus and sediment concentrations presented mean values of 0.07 mg L<sup>-1</sup>, 0.12 mg L<sup>-1</sup>, and 19 mg L<sup>-1</sup> for DP, TP and SSC, respectively. Significant levels of impairment on water quality were observed at sampling stations surrounding and receiving water from the urban area (City of Tupelo and Plantersville plants of water treatment). The most important source of SSC was the area under construction for the Toyota Assembly Plant at Blue Springs, MS. Tributaries downstream of the Town Creek at the Brewer Rd site were not important contributors of sediments and P; however, they do contribute a significant volume of flow allowing for a dilution effect that kept constant the mean SSC. Considering the 0.1 mg-TP L<sup>-1</sup> water quality criteria, the headwater areas were not impaired by P concentrations, while the tributaries near and after the urban areas presented P impairment showing mean concentrations values up to 1.2 mg-TP L<sup>-1</sup>.
Treatment of Timtek Process Water by Co-Composting
Year: Authors: Mangum L., Borazjani H., Seale R.D., Diehl S.V., Prewitt M.L., Sloan C.
The Timtek process involves crushing of small diameter trees to form mats which are coated with adhesive then pressed into boards. The crushing process yields effluent water that has a high biological oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS). This water must be remediated before it can be discharged into public water systems. A six month study was conducted to evaluate the effectiveness of co-composting of the process water with wood waste and chicken manure as a method of remediation. Wood waste from the pilot facility in Shuqualak, MS was ground into sawdust. This sawdust was composted using four treatments with deionized water or process water to adjust moisture content. Two treatments were amended with manure to provide a nitrogen source; two received only deionized water or process water. The compost end-products for all treatments were then evaluated for relative toxicity, weight loss, maturity and suitability as a container substrate in a greenhouse experiment using pansies. Additional testing was conducted to determine the toxicity of compost leachate and to evaluate the effects on germination rates of sensitive plant species. Co-composting successfully reduced the bulk and toxicity for all treatments. Treatments containing manure and process water showed over 90% emergence rate of radish seeds by day 90. The manure amendments were also comparable to the commercial greenhouse substrate in aiding plant biomass production. The end result of the experiment was the production of a bio-based value added medium that was non-toxic and suitable for soil amendment/potting mix.
Support for a Northeast Mississippi Regional Water Management Plan
Year: Authors: Tagert M.L.
Water and wastewater infrastructure are national priority issues for economic development, pubic health and environmental concerns. Currently, in predominantly rural states such as Mississippi, water supply infrastructure is operated and maintained largely by many independent small public water systems. Similarly, rural wastewater infrastructure is essentially nonexistent. As new development projects have recently been announced in Northeast Mississippi, regional water and wastewater organizations are critical for Northeast Mississippi Counties to plan, build, operate and maintain the necessary infrastructure to ensure an adequate water supply for the future and adopt a viable rate schedule to be self-sufficient. Recognizing this situation, the Tombigbee River Valley Water Management District (TRVWMD) is formally creating two new multi-county water and sewer organizations within their twelve member Counties. The ‘Tri-County District’ covers Itawamba, Prentiss, and Tishomingo Counties, while the ‘Five-County District’ covers Chickasaw, Clay, Kemper, Lowndes, and Noxubee Counties. All participating Counties have passed resolutions to establish a new Water and Sewer District, and the TRVWMD sought Mississippi State University’s assistance in completing a Water Management Plan for the Tri-County District, which is a requirement of the formal permitting process to establish a new District. This presentation will address the planning process and elements of the Tri-County Water Management Plan, which has a primary emphasis on water supply and contains contributions from various Northeast Mississippi stakeholders such as local, state, federal, and regional agencies and organizations.
Urban Stormwater Runoff Phosphorus Loading and BMP Treatment Capabilities
Year: Authors: Perry S., Garbon J., Lee B.
Continued land development through urbanization is deteriorating surface water quality. A significant concern with our limited global fresh water resources is the onset of toxic algae blooms and reduced dissolved oxygen due to continued, uncontrolled phosphorus loading from an ever increasing source, urban development. This is leading to negative ecologic, economic, and human health impacts. As a result, regulators are beginning to acknowledge the impairment of fresh water bodies, and have begun implementation of Total Maximum Daily Loads (TMDLs). However, applying phosphorus related TMDLs specifically to urban stormwater runoff may not be effective without first understanding the available mechanisms and limitations involved in phosphorus treatment for stormwater applications.<br /><br /> To achieve high levels of permanent phosphorus removal, review of the fate and transport of Phosphorus, including both particulate-bound and dissolved phosphorus, in urban stormwater runoff is necessary. Significant field monitoring data of various stormwater Best Management Practices (BMPs) exists which illustrates advantages and disadvantages of removal mechanisms, and ranges of performance variance in both conventional Best Management Practices (BMPs) as well as newer Low Impact Development (LID) applications.<br /><br /> Advances in phosphorus treatment technologies have recently become available and better understood, providing the ability to capture high levels of both particulate-bound and dissolved phosphorus. Amending both conventional BMPs and LID applications with engineered solutions offers increased ability to achieve existing and future phosphorus based TMDLs. These concepts, performance data and design amendments are discussed as a potential means to protect our fresh water resources from remaining eutrophication.
Sediment Budget Analysis for Town Creek Watershed, MS
Year: Authors: Ramirez-Avila J.J., Sharp J., McAnally W.H., Ortega-Achury S.L.
The Town Creek watershed is located in the Northeast area of Mississippi. It covers 1,769 km<sup>2</sup> and represents approximately 50% of the upper Tombigbee River basin area contributing to the Aberdeen Pool on the Tennessee-Tombigbee Waterway. The sediment yield from the watershed attributes to the estimated 320,000 ton/yr of deposition in Aberdeen pool, where annual dredging averages 310,000 ton/yr. To produce remedial measures for reducing water quality impairment, and dredging costs (expressed in terms of a percent reduction of sediment loads), and future BMP’s in Town Creek watershed, it is necessary to know the sediment sources and loads currently transported within the watershed. A sediment budget for a partial sub-basin within Town Creek watershed is investigated by means of experimental and modeling methods, including HEC-RAS and the Sediment Impact Analysis Method (SIAM). SIAM is a rapid assessment screening tool used to evaluate the impacts of sediment management activities and determine trends in sedimentation. The tool is incorporated in the latest version of the U.S. Army Corps of Engineers HEC-RAS model as a design module. Local sediment sources/sinks (e.g. tributary inputs, landuse practices) as well as the upstream and downstream boundary conditions are defined by using computational tools, field surveys, and sediment sampling. The analysis performed is expected to provide a general assessment of the sediment budget components within a representative watershed within the Tombigbee River Basin.
Interaction of the Mississippi River with the Mississippi River Valley Aquifer in Northwestern Mississippi
Year: Authors: Bordonne O., Barlow J.R., Coupe R.H.
The Mississippi River Valley Alluvial Aquifer (MRVA) in northwestern Mississippi is in direct connection with the Mississippi River, discharging into the River at times of base flow and being recharged by the Mississippi River at times of high flow. Modeling studies have indicated that over the long term, there is a net zero exchange of water between the Mississippi River and the MRVA. However, because of increased groundwater withdrawals for agriculture over the past few decades, groundwater levels have been declining in the MRVA; this decline has likely changed the interaction between the Mississippi River and the MRVA. Changes in surface- and groundwater interactions are important to understand, especially as local agencies attempt to implement policies to use the MRVA in a sustainable manner. In order to quantify the exchange between the Mississippi River and the alluvial aquifer, continuous data collected over the last decade from wells located near the Mississippi River were used to identify recharge and discharge periods and to estimate the net balance between the river and aquifer. Historical water-level data were also used to determine if the relation has changed over time.
The Effects of Land Use on Streams Along the Natchez Trace Parkway Using Rapid Bioassessment Protocols
Year: Authors: Earleywine B., Dibble E.
Stream quality is commonly assessed using the Environmental Protection Agency’s rapid bioassessment protocols for the habitat, fishes, and benthic macroinvertebrates. These assessments are useful to evaluate impacts that land use may have on streams. We conducted bioassessments in eighteen streams, identified land uses, and compared water quality parameters of forty-four streams along the Natchez Trace Parkway. We measured for potential land use effects by sampling water quality metrics (April 2008-February 2009), benthic macroinvertebrate and habitat assessment protocols (June 2008), and fish protocols (February 2009) to demonstrate differences across six subregional watersheds. The three dominant land uses were deciduous forest, pasture/hay, and evergreen forest respectively. Deciduous forest was most abundant in the Upper Cumberland, Lower Cumberland, and Tennessee watersheds while evergreen forest covered more area in the Mississippi, Pearl, and Tombigbee watersheds. Habitat assessment scores averaged highest in the deciduous forest-dominant watersheds and lowest in the blackwater stream watersheds dominated by evergreen forests. The Pearl watershed, comprised mostly of evergreen forest land, had the lowest average dissolved oxygen, alkalinity, conductivity, pH, and nitrate. Turbidity and total suspended solids decreased as latitude increased. Fecal <i>E.coli</i> colony estimates were highest in Mississippi and Upper Cumberland watersheds. Latitudinal differences were also observed in the macroinvertebrate assemblages. Tennessee, Lower Cumberland, and Upper Cumberland watersheds had more shredders and were the only watersheds with Plecoptera. Relationships between fish and macroinvertebrate integrities are discussed for each stream and watershed.
Turbidity as a Surrogate for the Estimation of Suspended-Sediment Concentrations in Mississippi Streams
Year: Authors: Runner M.S., Stocks S.J.
The U.S. Geological Survey currently collects suspended-sediment concentration data at more than 25 hydrologic monitoring stations in Mississippi. Data are collected to describe suspended-sediment concentrations and loads over the range in discharge for these stations and to determine if trends in the sediment-discharge relation exist, as well as describe changes in those trends. Where sufficient data are collected, they can be used to compute the load of sediment transported in suspension during storm events. <br /><br /> Traditional methods for obtaining suspended-sediment concentration data require the collection of water samples that are shipped to a laboratory for analysis. Depending on a variety of factors, it can take up to 6 months from the time of sample collection to receipt of laboratory results. To expedite the availability of these data to the cooperators, which will allow decisions to be made in a timely manner, the U.S. Geological Survey began a study to develop a method to estimate suspended-sediment concentrations using a surrogate. The method is based on the success of previous studies, which indicated that for streams with certain hydrologic and sediment characteristics, site-specific relations between turbidity and suspended-sediment concentrations could be developed, which allow the estimation of the sediment concentration. <br /><br /> For this study, turbidity data are being collected by using two methods. First, in situ water-quality monitors are installed at two continuous-record stations where discrete suspended-sediment concentration data are collected. Turbidity data are collected on a regular time interval, generally every 15 minutes, by water-quality monitors deployed in the water at these stations. The measured turbidity values are compared with the suspended-sediment concentrations in water samples collected by using automatic pumping samplers. Second, water samples collected at locations without continuous water-quality monitors are analyzed for turbidity by using a bench-top turbidity meter prior to the samples’ shipment for analysis. Water samples collected at stations with continuous water-quality monitoring are also analyzed using the bench-top meter so that comparisons can be made between the two methods.<br /><br /> Preliminary results indicate that reasonable turbidity-sediment relations can be developed for many of the stations that are currently being tested as part of this program. These relations could provide a means to estimate suspended-sediment concentration for water samples collected by automatic pumping samplers, as well as provide a means to reduce the costs associated with collecting data necessary for the evaluation of environmental projects.
Mississippi River Bluff Line Streams
Year: Authors: Starnes J.E.
A multitude of deeply incised, distinctive streams drain the Mississippi Loess Bluffs from Memphis southward to Natchez. These hydrologic features (and supported biota) are strongly influenced and controlled by complex Quaternary and Tertiary lithologic layers. These "bluff line streams" support unique, complex, and delicate sets of aquatic ecosystems, some of which are considered to be ice-age relics. Locally, these dendritic systems support the recharge of the Mississippi River Alluvial Aquifer (MARVA) as their trunk streams enter into the Mississippi River Alluvial Plain across copious, low relief, alluvial fans. These streams are threatened by in-stream mining, oil and gas production activities (shallow salt water injection, evaporation pits, and spills), industrial and housing development, deforestation, nonpoint source pollution such as agricultural runoff, solid waste dumping, and stream-bed alteration. Such activities can have profound negative impacts; degrading water quality, threatening aquatic/terrestrial biology, amplified erosion, localized excessive sedimentation, and spoiling sensitive, natural eco-system balances. Heightened awareness, study, and understanding of integrated and interdependent processes (geology, hydrology, biology) is essential to maintaining and sustaining delicate, unique, bluff line stream environments.
Fish and Invertebrate Assemblage Relations to Dissolved Oxygen at 35 Sites in Southern Louisiana
Year: Authors: Justus B.G., Wallace J.E.
From 2005 to 2007, the U.S. Geological Survey sampled fish and invertebrate assemblages and monitored dissolved oxygen during critical summer conditions at 35 stream sites in southern Louisiana. The purpose of the study was to assess relations between fish and invertebrate assemblages and dissolved oxygen, and to provide information that could be used to validate or refine existing aquatic life use categories and dissolved-oxygen criteria (5 milligrams per liter) for streams in southern Louisiana. Sites with a range of ecological conditions were selected for sampling by the U.S. Environmental Protection Agency Region VI, and nine sites were considered to be least impaired. Dissolved-oxygen concentrations were standardized to 0800, a time when concentrations were near the daily minimum, and were compared to approximately 370 biological metrics. Piecewise regression was used to evaluate biological metrics for break points to indicate a minimum (biological) threshold concentration for dissolved oxygen. Preliminary data indicate a biological threshold exists between 2 and 3 milligrams per liter of dissolved oxygen. This finding indicates that fish and invertebrate assemblages in low-gradient streams have adaptations that enable them to withstand low dissolved-oxygen concentrations.
Water Quality Monitoring Plan and Implementation, Lake Washington Mississippi, 2008
Year: Authors: Hicks M.B., Stocks S.J.
Lake Washington is located in Washington County in northwestern Mississippi, and drains into Washington Bayou, a tributary of Steele Bayou. The lake is an oxbow formed by an abandoned meander of the Mississippi River. About half of the land use in the watershed is agriculture: major crops are cotton, corn, soybeans, wheat, and rice. Although the watershed is relatively rural, housing development has increased near the lake since 2003. Water quality in Lake Washington has gradually declined during the last 30 years. In 1991, results of a study by the Mississippi Department of Environmental Quality (MDEQ) indicated that nutrient enrichment was affecting Lake Washington as a result of high phosphorus and nitrogen concentrations in the lake. In that same year, a watershed restoration project was initiated by MDEQ to demonstrate and assess best management practices to reduce sediment and nutrient concentrations in Lake Washington. Results of a follow-up study by MDEQ in 1996 indicated that nutrient enrichment in Lake Washington was continuing due to continued high phosphorus and nitrogen concentrations in the lake. <br /><br /> A group of State and Federal agencies and local organizations, known as the Yazoo Basin Team and part of the Basin Management Approach of MDEQ, identified Lake Washington as a priority area for watershed restoration, and as a result, the Lake Washington Watershed Implementation Team was formed in 2005. The team developed a Watershed Implementation Plan in 2007 with the goal of improving water quality of Lake Washington, in which reduction of sediment and nutrient loads were considered high priorities. The plan calls for reduction of sediment loading by 55 percent and associated organic matter loading by about 50 percent through implementation and maintenance of various best management practices. In coordination with water-quality improvement efforts outlined in the Watershed Implementation Plan, water-quality data are being collected to document suspended-sediment and nutrient characteristics of Lake Washington and loads in runoff entering Lake Washington before, during, and after implementation of efforts outlined in the plan. Nutrient concentrations (nitrogen and phosphorus), suspended sediment concentrations, and flow at two major inflows of Lake Washington are being monitored by the U.S. Geological Survey, and MDEQ personnel are collecting nutrients and chlorophyll-a data at two main lake sites. In addition, multi-parameter water-quality sondes will be deployed by USGS at two sites near the two MDEQ main lake sites, at a single depth (approximate of the middle of photic zone) to collect hourly readings of water temperature, specific conductance, dissolved oxygen, pH, and turbidity.
Water-Quality Data of Selected Streams in the Mississippi River Alluvial Plain, Northwestern Mississippi, September–October 2007-08
Year: Authors: Hicks M.B., Stocks S.J.
Between September 2007 and October 2008, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency and the Mississippi Department of Environmental Quality, collected and analyzed water-quality samples from streams in the Yazoo River basin within the Mississippi River Alluvial Plain in northwestern Mississippi. Water-quality samples were collected and analyzed for various physical and chemical characteristics, including but not limited to suspended sediment, nutrients, and chlorophyll a. In addition, continuous field parameter measurements (water temperature, pH, specific conductance, dissolved oxygen and turbidity) were collected at 30-minute intervals for a minimum of 72 hours using deployed multi-parameter water-quality sondes. In 2007, water-quality samples were analyzed from 56 sites located across the study area with continuous data measured at 28 of these sites. In 2008, water-quality samples were analyzed and continuous data measured at an additional 16 sites across the study area. Data collected throughout this project will be used in the development of water-quality indicators to assess water-quality health. These indicators will assist in the development and evaluation of restoration and remediation plans for water bodies not meeting their designated uses, as stated in the U.S. Environmental Protection Agency’s Clean Water Act Section 303(d).
Beneficial Use of Marginal Quality Water
Year: Authors: Kellogg W.
The Mississippi Alluvial Aquifer is the most heavily used aquifer in the state of Mississippi. Extensive use of the aquifer has overdrawn the aquifer in some areas and caused large cones-of-depression making continued pumping at the current rate unsustainable. The alluvial aquifer overlies deeper aquifers of the Mississippi Embayment Aquifer system. The alluvial aquifer can be as much as 250 feet thick and the Mississippi Embayment Aquifer system can be as much as 6,000 feet in thickness. Water usage is approximately 2 billion gal/day from the alluvial aquifer and 433 million gal/day from the deeper Mississippi Embayment Aquifers.<br /><br /> Many of the deeper aquifers contain fresh water (<500 mg/l TDS) in the northern part of the Mississippi Embayment, but TDS concentrations increase in the southern portion of the Embayment making the water unsuitable as a potable water supply without treatment. Many industries use fresh water supplies when they could be using brackish water (TDS 1,000 to 10,000 mg/l). In addition, desalination technology has improved a great deal in the past decade making desalination of brackish water a cost effective solution for obtaining additional sources of water supply. <br /><br /> Desalination of brackish water is becoming common in Florida, Texas, and California. Other states are now beginning to look at their brackish water aquifers as potential future supplies of potable water.
Improving the Capacity of Mississippi’s Rural Water Associations Through Board Management Training
Year: Authors: Barrett J.
The Mississippi legislature enacted legislation designed to increase the capacity of Mississippi’s rural water associations’ boards and small municipal water systems’ government officials to provide safe drinking water and be aware of the technical and legal responsibilities assumed by these individuals. This legislation mandated that the Mississippi State Department of Health (MSDH), in cooperation with other organizations such as the Mississippi Rural Water Association (MSRWA), provide training to the governing bodies of these systems. To this end, the MSDH contracted with the Mississippi State University Extension Service (MSUES) to develop training curricula and provide coordination and evaluative services to facilitate the provision of quality training opportunities accessible to clientele across the state. Furthermore, partnerships between MSUES, MSRWA, the Mississippi Water and Pollution Control Operators Association, and the Community Resource Group, have resulted in the development of several cutting edge curricula that have been nationally recognized.
A New Hydro-Enforced, 1:24,000 Digital Elevation Model for Mississippi
Year: Authors: Steil J., Walker S.
A new, 10 meter, statewide, hydro-enforced, digital elevation model [DEM] was recently developed by the Mississippi Automated Resource Information System [MARIS] in cooperation with the USGS to better support modeling efforts than the previous 30 meter DEM. The utility of the old 30m DEM was limited by scale, artifacts of processing, and substantial data exclusions such as the Tenn-Tom Waterway and significant migration of the Mississippi River. The new model was developed over a number of years beginning with Mylar separates of 7.5 minute quadrangles. Mylar separates were scanned, vectorized, and resulting lines tagged with elevation values and other attributes. As contour lines are not contiguous across individual quad maps, each contour was connected to the contour of the adjacent quad to create a continuous line for a seamless coverage. Carrying contours were added throughout the state to ensure proper hydrologic modeling. Digital Rater Graphics [DRG’s] were also available to provide clarification for incorrectly tagged elevation values especially at quad boundaries. The 2007 National Aerial Imagery Program [NAIP] 1 meter imagery was used to perform the inclusion and proper placement of the Tenn-Tom Waterway as it was not included in many of the original quadrangles. NAIP imagery was also the basis for correcting the placement of the Mississippi River which had migrated up to 5 miles from the position on the original 7.5 minute maps. Some corrective hydrologic changes were made to the 1:24,000 National Hydrologic Dataset [NHD] to provide more accurate modeling. Partially as a result of this project, MARIS has become the steward of the NHD for Mississippi. Preliminary geometric changes were made to the NHD to reflect changes in the landscape since the publication of the quad maps. These changes were most common in the Delta region and will be incorporated into the official NHD. Due to software limitations, each county was processed separately with a 400 meter buffer. The ESRI Topo-to-Raster command was used to generate each county DEM. Each County was checked by USGS at Rolla, MO. The final DEM’s are included as part of the official National Elevation Dataset [NED] and are available for download from USGS or MARIS.
Transport of Non-Point Source Contaminants Through Riparian Wetlands in the Mississippi Delta Region
Year: Authors: Noakes E., Davidson G.R., Wren D.G., Utroska S.G.
A joint research group at the University of Mississippi and the USDA ARS National Sedimentation Laboratory has been investigating the fate and transport of non-point source contaminants entering riparian wetland systems from agricultural lands. Results to date suggest that short-term studies documenting sequestration of chemically persistent contaminants in riparian wetlands are not sufficient to document long-term containment of these substances. In previously reported work, elevated concentrations of Pb and As were found at particular depths in open-water sediments in Sky Lake, but not in contemporaneously deposited sediments in the surrounding wetlands. Depositional dates of the zones of elevated concentration, based on <sup>210</sup>Pb and <sup>137</sup>Cs measurements, were consistent with the timing of lead arsenate use in the vicinity. The absence of similar concentration spikes in the wetland sediments led to the working hypothesis that contaminants such as Pb and As may be initially scavenged from water flowing through a riparian wetland, but over time are flushed out into adjacent lakes or streams. Within the wetland, seasonal inundation and aeration results in decomposition of litter, remobilization of contaminants bound to organic matter, and redistribution by rising and falling water levels. Permanent sequestration occurs only with burial in the perennially flooded open water environment. The study has been expanded to additional lake-wetland systems in the Mississippi Delta region to determine if evidence of long-term flushing of contaminants from riparian wetlands is a common occurrence.
Climatological and Cultural Influences on the Potential for Conservation of Groundwater in the Mississippi Delta Shallow Alluvial Aquifer by Substitut
Year: Authors: Wax C.L., Pote J.W., Merrell T.L.
The shallow alluvial aquifer in the Mississippi Delta region is heavily used for irrigation of corn, soybeans, and cotton, as well as for rice flooding and filling aquaculture ponds in the prominent catfish industry. Water volume in the aquifer is subject to seasonal declines and annual fluctuations caused by both climatological and crop water use variations from year-to-year. The most recently documented water volume decline in the aquifer is estimated at 500,000 acre-feet. <br /><br /> Available climate, crop acreage, irrigation water use, and groundwater decline data from Sunflower County were used to construct a model that simulates the effects of climatic variability, crop acreage changes, and specific irrigation methods on consequent variations in the water volume in the aquifer. Climatic variability was accounted for by predictive equations that related annual measured plant water use (irrigation) to growing season precipitation amounts. This derived relationship allowed the application of a long-term climatological record (48 years) to simulate the cumulative impact of climate on groundwater use for irrigation. <br /><br /> Use of the model to simulate changes in irrigation methods and crop acreages from 2008 through 2055 shows potential to stabilize the water volume in the aquifer through implementation of various management strategies. Four scenarios of water management were simulated—static land use/water use in 2006, total efficient irrigation methods, total inefficient irrigation methods, and enhanced surface water use when available in place of groundwater for irrigation. These simulations illustrate the power of the model to assess the long-term impact of climatic variability and changes in the cultural practices on groundwater use in the region. The model is therefore a tool that will be useful in making management decisions that will allow sustainable use of the groundwater resource.
Runoff Modeling of the Luxapallila Creek Watershed Using Gridded and Lumped Models
Year: Authors: Diaz-Ramirez J.N., Johnson B.E., McAnally W.H., Ramirez-Avila J.J.
The Northern Gulf Institute is funding a project focus in improving watershed-wide decision support for resource management agencies; one of the tasks in this project is define the sensitivity of rainfall-runoff results to use of advanced tools, such as the Corp’s distributed hydrologic model Gridded Surface Subsurface Hydrologic Analysis (GSSHA) and the EPA Hydrologic Simulation Program—FORTRAN (HSPF). GSSHA is a physics based watershed model simulating 2D overland flow, 1D channel flow, and surface water/groundwater interaction. The HSPF software is a conceptual, continuous, lumped parameter watershed model that has been extensively used around the world since 1980. This study evaluates the GSSHA and HSPF runoff performance in the Luxapallila Creek watershed, Alabama and Mississippi. The 1,851 km<sup>2</sup> watershed drains into the Tombigbee River. Six NOAA raingauge stations are used as hourly input precipitation. Land use distribution using the 1980 GIRAS database shows 73% forest, 20% agricultural land, and 6% wetlands. USGS 30-m resolution digital elevation models (DEMs) are used to delineate and calculate physiographic parameters (e.g., area, slope, and length of slope). The State Soil Geographic (STATSGO) database depicts mainly sandy loam soils. The GSSHA model grid size is 100 m x 100 m, resulting in 185,816 grids. The HSPF model is divided in 50 subwatersheds. Daily streamflow data collected by the USGS at the 02443500 station are used for model evaluation. The Web-based hydrograph separation system (WHAT) is used to calculate runoff and baseflow from observed streamflow data. Observed and simulated runoff data are evaluated using the following statistics: peak error, volume error, flow error, and peak time error. Four storm events are analyzed for the period 01/01/1989 to 03/31/1989. GSSHA peak, volume, and flow errors were around half of HSPF results. Both models showed ahead peaks of one day. However, the GSSHA model results matched the peak of two out of four storm events. The HSPF model runs faster than GSSHA (5 seconds vs 20 hours). GSSHA and HSPF groundwater modules will be setup and evaluated.
Detection of <i>Salmonella spp.</i> from Mississippi Coastal Waters and Sediment
Year: Authors: Carr M.R., Ellender R.D., Flood C.
Traditionally, the examination of individual pathogens for assessment of water quality has not been employed. This is mainly due to the cost and time requirements required to perform the appropriate morphological and biochemical analysis for positive identification of these pathogens. However, the employment of molecular analysis techniques supplemented with traditional techniques allows for more rapid and accurate identification. The main goal of this research is to determine if the marker <i>stn</i>, which codes for an enterotoxin gene specific for salmonella, is present within Mississippi Gulf Coast waters and creek systems, which flow into the Gulf. This research also is aimed at determining if the salmonella marker is present within coastal sediments. Environmental factors such as salinity, temperature, tidal currents, and significant weather related events will be examined to understand the relationship to the presence of the salmonella marker. Examination of salinity’s effect on both laboratory grown and environmentally isolated <i>Salmonella</i> indicates a difference in the survivability of this pathogen within given concentrations of NaCl <i>in situ</i>. Analysis of <i>Salmonella</i> subspecies in coastal waters and sediments using both traditional and genetic analysis has demonstrated that this bacterium is frequently found in samples from fresh water creeks but is found infrequently in coastal waters. Further, sediment samples to date have not revealed the presence of <i>Salmonella</i>, implying that this environment is not conducive to the survivability of this animal pathogen.
Sources and Transport of Total Nitrogen from Major River Basins of the South-Central United States, 2002
Year: Authors: Rebich R.
A spatially-referenced regression on watershed attributes (SPARROW) model was developed for a 2002 base year for streams in the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins to describe total nitrogen loadings to the northwestern Gulf of Mexico. Ultimately, model results may be used to help develop water management plans to reduce, control, and mitigate nutrient inputs throughout the study area. Total nitrogen loads and yields generally were highest near streams in the eastern part of the study area in the Lower Mississippi basin and along reaches near the Texas and Louisiana shoreline. The highest individual source of nitrogen for the study area was from wet deposition of total inorganic nitrogen, which accounted for 36 percent on average of total nitrogen in streams from the study area. Land application of manure from confined feedlots and manure generated in pastures accounted for 22 percent, nitrogen fixation from fertilizer applications accounted for 17 percent, and nitrogen from commercial fertilizers accounted for 12 percent on average of total nitrogen in streams from the study area, which combined totaled 51 percent from agricultural and pasture land uses. Urban sources of nitrogen totaled about 13 percent on average of total nitrogen in streams from the study area, of which urban nonpoint runoff accounted for 9 percent and municipal and industrial point sources about 4 percent. <br /><br /> For the Yazoo River basin in northwestern Mississippi, preliminary estimates of total nitrogen load and yield were about 21,300 metric tons and about 0.64 metric tons per square kilometer, respectively, both of which agree with literature estimates for the sampling station located near the mouth of the Yazoo River prior to release into the Mississippi River. The total nitrogen load from the Yazoo represents about 2.2% of the total nitrogen load of the Mississippi River near its mouth. Nitrogen from atmospheric deposition accounted for about 25 percent of the total load leaving the Yazoo River basin. Agricultural sources accounted for about 67 percent of the total load: 31 percent by commercial fertilizers, 30 percent by nitrogen fixation from fertilizer applications, 5 percent from pastures, and 1 percent from land application of manure from confined feedlots. Urban sources of nitrogen accounted for the remaining 9 percent of the total load from the Yazoo River, of which about 5 percent came from municipal and industrial point sources and 4 percent came from urban nonpoint runoff.
Hydrogeology of the Central Delta (East-Central Sunflower County and West-Central Leflore County)
Year: Authors: Byrd C.B.
For the last several years there has been growing concern regarding the declining water levels in Mississippi River Valley alluvial aquifer (MRVA) in the central Delta. Analysis of water levels alone does not answer the question of how much water is actually remaining in the aquifer. The only way to determine this is to know where the base of the aquifer is in relation to the water level at any one site. Therefore, in the summer of 2004 staff of Mississippi Department of Environmental Quality’s Office of Land and Water Resources (OLWR) began a drilling program to gather this type of information. <br /><br /> Twice each year, staff of the Yazoo-Mississippi Delta Joint Water Management District (YMD) collects water level data from wells screened in the MRVA throughout the entire Delta. Most of the drill sites for this project have been very near some of these wells. The minimum depth drilled at all the sites has been 300 feet. This depth allows not only the entire thickness of the MRVA to be penetrated, but a portion of the underlying formation, as well. Data collected from the water level measurements and drilling enables changes in the saturated thickness of the aquifer at each of these MRVA well sites to be monitored through time. <br /><br /> Throughout the Delta, the surface of the formation(s) underlying the MRVA is an erosional surface; therefore, the contact between the two is an unconformity, resulting in an extremely variable MRVA thickness. Most publications report that the average thickness is approximately 135 to 140 feet. In the project area the average depth of the base of the aquifer is 131 feet below ground surface, with the range of depth between 90 and 166 feet. The water level in the MRVA is approximately 50 feet below ground surface. As most irrigation / catfish culture wells have 40 feet of screen, the most serious scenario is where these wells are screened where the MRVA base is less than 100 feet below ground surface. At these sites, the static water level is either only a very few feet above the top of the well screen or at the top of the screen; and during periods of pumping, the water level is below the top of the screen. <br /><br /> Continued investigation of the geology is an important key to understanding the hydrology of the alluvial aquifer in this area. A better understanding of how this aquifer system works will allow officials to properly and effectively manage this tremendous resource.
A Study of the Effectiveness of Various Sedimentation Solutions and Practices
Year: Authors: Davis T.
This report will show the effectiveness of various types of solutions and practices used to reduce, prevent or change sedimentation patterns within areas of navigational interest. Most modern shipping facilities maintain deeper depths than occur naturally to accommodate the size of the world’s ever growing merchant vessel. Deepening of such facilities such as anchorage basins, ship channels, etc are usually met with sediment deposition, which must be removed or prevented to maintain efficient shipping operations. Maintenance dredging has become the primary tool for the upkeep of underwater navigation dimensions, but it also has a number of downfalls in its operation, which has become more prevalent over the years. Likely, the most obvious problem with dredging is the lack of a permanent solution, for maintenance dredging removes unneeded sediment rather than addressing the processes creating deposition. Many other concerns are associated with maintenance dredging such as: expensive operation costs, difficulty to secure small contracts, downtimes in shipping operations and worries of ecological distress. These problems have created interest in solutions or practices to reduce or prevent the amount of sediment deposition within maintained depth facilities and ultimately reduce the amount of maintenance dredging needed, which may result in significant economic benefits.
Gulf Coast Watersheds and Water Education: Outreach Alignment and Best Practices
Year: Authors: Clary R.M., Brzuszek R.F.
Previous research (Fulford, Brzuszek, & Roberts, 2008) assessed the impact of ordinances, outreach, and enforcement on the resiliency of the northern Gulf Coastal watersheds. Four watersheds in Louisiana, Mississippi, Alabama, and Florida were selected, and 22 non-governmental organizations (NGOs) in the target watersheds were surveyed with regards to water quality monitoring, environmental education, and watershed management. Detrended Correspondence Analysis (DCA) revealed that the most relevant programs for each watershed varied. Whereas Tchefuncte/Bogue Falaya’s NGOs (LA) tended towards a management plan, the Biloxi River Watershed (MS) focused upon conservation easements and managing land restoration. The Fish River Watershed (AL) exhibited more centralized efforts with a tendency toward conservation, partnerships, and policy. The New River Watershed (FL) was strongest toward development review and education. Our current research extended the results of this initial study to investigate how the focus of each watershed reflected or paralleled their state’s educational goals, benchmarks, and grade level expectations. The educational programs were also analyzed for correspondence to the National Science Education Standards. We included those educational outreach programs aimed toward K-12 students, and analyzed the NGOs’ educational products for alignment with state curricula and national science standards. Additional investigation of other watersheds’ educational programs (e.g., Chesapeake Bay) provided benchmarks against which the northern Gulf Coast watershed programs were compared. Our research resulted in the identification and development of best practices for the implementation of effective Water Education programs that include ecology, water management, and water quality focus.
Collection of Hydrologic Data on Tidally Affected Streams
Year: Authors: Runner M.S., Massingill D.K.
The U.S. Geological Survey began collecting streamflow and other hydrologic data in Mississippi in the late 1800’s. Until recent advances in acoustic technology and its application to hydrologic data collection, it was difficult to collect accurate streamflow data on rivers and streams where stage-discharge relations were affected by varying tide. The greater the tidal affect, the more difficult the data collection. On streams where tides cause the flow to fully reverse, the collection of reasonably accurate continuous data was practically impossible.<br /><br /> By using acoustic technology to collect time-series velocity data and make discharge measurements, the U.S. Geological Survey now operates and maintains four continuous-record surface-water discharge stations, and an additional station where the technology is used to monitor bed scour at bridge piers. At one of these stations, the varying tide primarily affects periods of low flow. At the remaining four stations, the flow fully reverses direction as the tide changes. The streams range in size from large rivers such as the Pearl and Pascagoula Rivers, to small first order streams such as Bayou Heron in the far southeastern part of the State. Data also were collected at monitoring stations (which are now discontinued) on the Escatawpa and Jourdan Rivers. It has been observed that the smaller the stream and corresponding flow, the greater the effect the tide has on the stream, and not surprisingly, the more difficult the data collection.<br /><br /> The computation of discharge on a tidally affected stream requires the collection of data to develop relations between the stage, or water level, and the cross sectional area, and between an index velocity measured by an in situ velocity sensor and an average velocity computed from a streamflow measurement. It is the collection of these two data sets and the product of the computed area and average velocity that provides continuous discharge values.
Conjunctive-Use Optimization Modeling of the Mississippi River Valley Alluvial Aquifer: Evaluation of Groundwater Sustainable Yield
Year: Authors: Czarnecki J.B.
The Mississippi River Valley alluvial aquifer (the alluvial aquifer) is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. The alluvial aquifer ranks third among the most productive aquifers in the United States. In 2000, more than 9 billion gallons per day of water were pumped from the alluvial aquifer by more than 45,000 wells, primarily for irrigation and for fish farming. Since the widespread agricultural use of the aquifer began, several large cones of depression have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas. <br /><br /> Conjunctive-use optimization modeling was done to assist water managers and planners by estimating the maximum amount of groundwater that hypothetically could be withdrawn from alluvial wells and from hydraulically connected streams without violating hydraulic-head or streamflow constraints. Optimization models showed that continued pumping at 1997 rates are unsustainable without violating head constraints imposed as a part of Arkansas’s Critical Groundwater Area criteria. Streamflow constraints specified within the model were based partly on minimum flow requirements for maintaining either navigation requirements, water quality, or fish habitat. Continuously pumping at 1997 rates resulted in water levels dropping below the hydraulic-head constraints (either half the aquifer thickness or 30 feet of saturated thickness), making those rates unsustainable. Optimized sustainable pumping was obtained such that water levels were maintained at or above the hydraulic-head constraints, and streamflow was maintained at or above minimum flow requirements. No single value of groundwater sustainable yield exists, as it depends on the specification of water-level and streamflow constraints, and the specification of potential groundwater and stream-withdrawal locations and their maximum allowable withdrawal rates.
The Effect of Policy and Land Use Change on Water Quality in a Coastal Watershed City: An Analysis of Covington, Louisiana
Year: Authors: Langley K., Schauwecker T., Wilkerson W., Walker J.
There is currently a great need to expand the understanding of land use policy’s impact on water quality. The purpose of this work is to examine local policy in Covington, Louisiana in order to assess its impact on land use. Land use is then analyzed to reveal effects on water quality. Water quality should then be used to dictate policy in a feedback loop, but that is not currently happening. Methods used include reclassifications of land use categories within a Geographical Information System and analysis of changes over a four year period. Policy is assessed using two instruments. The first is a pre-existing evaluation method devised by The Center for Watershed Protection. The second is by a more flexible and generalized apparatus developed by staff and faculty in the Department of Landscape Architecture at Mississippi State University. Three water quality parameters are examined for impairment due to their known correlation to urban runoff. Nonpoint source pollution from agriculture is also discussed, however, for analysis of policy and land use in the City of Covington, this is less of an issue.<br /><br /> While it has been determined that Covington’s water quality related policy is insufficient and surface waters are impaired, there are a great deal of extenuating circumstances that impact water quality both in and around the city. Changes to current monitoring efforts and policy drivers are discussed along with suggested improvements that could be made to altered landscapes and current governance.
Arkansas&rsquo Expanded Relational Water-Use Program
Year: Authors: Holland T.W.
The Arkansas Water-Use Program is a cooperative effort between the Arkansas Natural Resources Commission (ANRC) and the U.S. Geological Survey (USGS). Site-specific data for several water-use categories are reported annually by water users and are electronically stored. Water users that withdraw 1 acre-foot or more of surface water per year or operate wells with the capability of pumping 50,000 gallons of ground water per day or more must report their withdrawals. Site-specific water-use data for irrigation, livestock, duck hunting clubs, public supply, commercial, industrial, mining, and power generation are stored in the Arkansas Water-Use database developed and maintained by the USGS Arkansas Water Science Center (AR WSC). Data for the irrigation, livestock, aquaculture, and duck hunting club categories are reported through the Conservation District offices in selected counties. Users report data for about 54,000 agricultural measurement points through the County Conservation District offices via a secure internet Web page that is the entry point into the Arkansas Water-Use Data System. Water-use data for the other categories are reported directly to the Arkansas Natural Resource Commission on paper registration forms generated by AR WSC staff as output from the data base management system. These forms are mailed out by ANRC staff to about 1,200 additional water users that do not report their water use via the Web. The completed registration forms are returned to U.S. Geological Survey for entry in to the Arkansas Water-Use Data Base System. The amounts of water withdrawn, sources of water, how the water was used, and how much water was returned are available to water-resources managers and policy makers through retrievals from the Arkansas Water-Use Data Base System.<br /><br /> Expansion of the Arkansas Water-Use System began 3 years ago for multiple reasons. ANRC needed a viable way to store and retrieve water-well construction information that Arkansas law requires be reported to the Arkansas Water-Well Commission (a component of ANRC) and, the understanding of ground-water use would be enhanced with a relational link to well construction information; and, a better understanding of hydrogeologic structure would further compliment ground-water use understanding and provide enhanced information concerning water-bearing zones contributing to wells. Consequently, tables have been added to the system as a repository for water-well construction data and a Well Log Archive. Staff at the ANRC enters data into the water-well construction tables. Construction data for approximately 57,000 wells reside in the database at this time. Well log archiving is a continuing effort, in the ANRC/USGS cooperative program, to archive and interpret borehole geophysical logs. As a part of our continuing cooperative program, well logs for a few Arkansas counties are scanned and geo-referenced each year - 12 counties have been completed to date. The tops of aquifers and confining units are interpreted from these logs for the purpose of creating a digital framework of the subsurface. This framework of hydrogeologic units is used in conjunction with a reported water-use location to determine/verify contributing aquifers. This is a "visual" process, using an interactive mapping application.
Sulfate Removal From Ground Water
Year: Authors: Bricka R.M., Stokes B.
A process to remove sulfates from ground and surface water to meet required drinking water standards has been completed. Several options were researched, including ion exchange, electrodialysis, electrodeionization and other membrane technologies. In evaluating each process, economical, environmental, health and safety issues were considered. A primary concern during assessment was the feasibility of scaling up a bench scale process to a system that can produce hundreds to thousands of gallons. While many of these are innovative technologies, ion exchange is a more commonly accepted process and is suitable for large scale production because of the lower operation costs. <br /><br /> This paper describes the process by which ion exchange technology occurs as well as the recommended design for scale up. The prototype design includes two columns packed with anion exchange resin. For the chosen set-up, one column will purify water, and the other column can be regenerated without interrupting continuous production. Multiple equilibrium and dynamic tests were performed to calculate the sulfate absorption capacity of the resin and determine the optimum treatment rates for maximum efficiency. The Environmental Protection Agency has numerous regulations and standards providing recommended contaminant levels of sulfates in drinking water. These standards provide a basis for testing and design. The process was scaled to purify 120,000 gallons of water per day while minimizing the concentrations of sulfates and other dissolved solids. All equipment, product, and operational costs were calculated and evaluated. Several waste treatment options were also evaluated, and a recommended design to employ evaporation ponds was chosen based on geographic location and arid climate. In the chosen waste treatment option, all regenerative waste is sent to an evaporation pond to recover and dispose of excess salt. The process of ion exchange successfully removed an adequate amount of sulfates and was proven to be a feasible solution for water treatment in areas with high sulfate concentrations.
Drainage Improvement Project Development for Successful Hazard Mitigation Funding
Year: Authors: Talbot M.T., Quarles J.E., Bass D.L., Jourdan N., Swagart G.
Over 100 drainage improvement project proposals were considered for Katrina Hazard Mitigation Grant Program (HMGP) funding in 2008 and 2009, by the Mississippi Emergency Management Agency, with assistance from FEMA. Many of these project proposals displayed technical merit and detailed the scope of work and estimated project costs. Completion of these projects could have reduced future flood levels and associated future flood damages in many communities. However, most of these proposals had insufficient damage history data needed to determine the benefits of the mitigation projects. Benefits are defined as avoided damages, disruptions, losses, etc., as a result of the mitigation. For HMGP funding approval, the FEMA Benefit Cost Analysis (BCA) musts show that the benefits of a project are equal to or exceed the project cost. The FEMA Damage-Frequency Assessment (DFA) BCA module is used for localized drainage improvement projects when Flood Insurance Study (FIS) or comparable data are not available. This paper presents an overview of the DFA module and the necessary documentation requirements. Further, suggestions for developing routine collection of the needed documentation to apply the DFA module for drainage improvement projects are outlined. This information will assist communities to be better prepared to successfully apply for HMGP funds that might be available in the event of future disaster declarations.
Preliminary Assessment of Ecosystem Services Provided by Moist-Soil Wetlands
Year: Authors: Spencer A.B., Kaminski R.M.
Management of moist-soil wetlands is intended to promote seed and tuber producing annual vegetation and production of aquatic invertebrates, both of which provide critical food for waterfowl and other wetland wildlife. Moist-soil management of marginal cropland and other similar lowlands can potentially enhance quality of discharge water and run-off in agricultural landscapes such as the Mississippi Alluvial Valley. Seasonal decay of wetland vegetation sustains nutrient cycling and is the foundation of detrital based food webs in these systems. Crayfish (<i>Procambarus</i> sp.) populations are dependent upon the detrital based food web, provide a source of protein and other nutrients for wetland wildlife, and can be harvested for human consumption. During late-winter to early summer 2009, we monitored water quality, detritus accumulation and decay, invertebrate abundance, and crayfish harvest characteristics in public and privately managed moist-soil wetlands throughout Mississippi. The results from our monitoring efforts will be used to estimate potential ecosystem services provided by moist-soil management such as sediment abatement, nutrient retention, invertebrate production, and crayfish harvest. Demonstrating multiple ecological and economical benefits of moist-soil wetlands may encourage landowners to develop and manage natural wetlands within guidelines of conservation programs such as the Farm Bill’s Wetland and Conservation Reserve Programs.
Science Education on the Tennessee-Tombigbee Waterway: An Outreach Effort for K-12 Students and Teachers in Northeast Mississippi
Year: Authors: Langley K., Kerzel D.
Mississippi University for Women’s (MUW) <i>Science Education on the Tennessee-Tombigbee Waterway</i> project endeavors to provide enhanced science education opportunities for K-12 students and teachers in northeast Mississippi. As an institution, MUW has established itself as a leader in Mississippi by offering relevant and innovative educational outreach programs. In particular, the Department of Sciences and Mathematics has a strong track record spanning over a decade of providing high quality science and mathematics enrichment for elementary, middle, and high school groups. By working to increase the knowledge base in science and mathematics, our programs will enable Mississippians to better meet the challenges of the future.<br /><br />In this program, hands-on science and mathematics activities for students and teachers will be the central focus. These programs will be made useful to participants in one of two contexts: (1) how information presented can be used to improve the quality of life for people, and (2) how it can be used to benefit the environment. Workshop activities will take place primarily at the Plymouth Bluff Environmental Center, a learning facility which is part of MUW. The MUW Explorer, a 36’ by 10’ pontoon boat which has been designed as a floating teaching laboratory, will be used to engage participants in science activities on the Tennessee-Tombigbee Waterway. Other activities will be outdoors at Plymouth Bluff and in the classroom setting there. These activities will allow the participants to construct their own understanding of science in a real-world setting. Specific topics covered include forest and aquatic ecology, wildlife biology, geology, astronomy, and sustainable living strategies. Much of the program will focus on hydrology workshops conducted on the waterway. These programs will educate teachers and students on chemical and physical properties that dictate water quality, aquatic macroinvertebrates and benthic index concepts, nonpoint source pollution caused by rural and urban landscape alteration, responsible watershed management, and stream morphology, ground water concepts, and the importance of wetlands.<br /><br /> Participants will be evaluated to assess the success of the program in terms of teacher competency and utilization of material in classrooms and student interest and performance in science. Demographic information will also be collected and analyzed to assure that people of all racial, ethnic, socioeconomic, and ability levels are taking advantage of our programs. Work for this entire outreach project has been supported by a generous congressionally funded grant.
Restoring Canebrakes to Enhance Water Quality Along the Upper Pearl River
Year: Authors: Jolley R., Neal D., Baldwin B., Ervin G.
Large stands of rivercane [<i>Arundinaria gigantea</i> (Walt.) Muhl.], called canebrakes, initially covered millions of acres in the southeast US, playing a pivotal role in the hydrology, landscape ecology, and the cultural history of the First Nations of the Southeast. Because canebrakes are composed of very dense stands of rivercane, they act as ideal riparian buffers, dispersing overland flow, increasing soil porosity, and stabilizing streambanks. Unfortunately, large canebrakes have all but disappeared from the landscape due to overgrazing, agriculture, and altered fire regimes. In an effort to enhance water quality and wildlife habitat along the upper reaches of the Pearl River, a rivercane restoration project was initiated in June 2008. Over 1,000 rivercane seedlings were planted at eleven locations along a half-mile stretch of the Pearl River on land belonging to the Mississippi Band of Choctaw Indians (MBCI). Planting sites were selected as those susceptible to erosion (outer bends) and deposition (inner bends) in order to monitor the effect of canebrake establishment on stream bank stabilization. An additional nine sites were chosen along this same stretch for comparison (three sites with established rivercane and six without). Sediment markers were installed to monitor sediment depths within and outside of planting areas. Additional sediment markers were also inserted horizontally into eroding banks to monitor bank-sloughing along planted areas. Preliminary data indicate low survivorship in plantings at elevations susceptible to extended periods of inundation (<3 m above normal flow). Both planted and unplanted banks show moderate rates of erosion. Due to slow initial growth, rivercane seedlings may require several years to form effective riparian buffers.
Collective Action Regimes in Inland Marine Port Clusters: The Case of the Tenn-Tomm Waterway System
Year: Authors: Miller C., Stich B.
This paper analyses the competitiveness of the public-private Tennessee-Tombigbee Waterway system from a cluster perspective, discussing the importance of local governance and collective action regimes for the competitiveness of the cluster. The case study of the Tenn-Tomm port cluster shows how the collective action regimes have developed in this cluster. This study compares the Tenn-Tomm to a similar study done by de Langene and Visser (2005) comparing the Lower Mississippi port cluster to the seaport cluster of Rotterdam. A number of collective action problems require effective collective action regimes that render significant public benefits at the cluster level. Several public policy proposals are formulated to improve the quality of the public-private collective action regimes and hence enhance the performance of the Tenn-Tomm waterway system.
Hydrologic Services Provided by the National Weather Service
Year: Authors: Reed D.B., Graschel J.
The National Weather Service (NWS), part of the National Oceanic and Atmospheric Administration (NOAA), is responsible for providing river and flood forecast sand warnings across the country to save lives and property. The NWS has 122 Weather Forecast Offices (WFOs) across the country that maintain a 24-hour weather watch and provide watches and warnings for severe weather and flooding. The NWS operates 13 River Forecast Centers that model the most important portions of the hydrologic cycle and use those models to provide forecasted river levels for five days into the future. <br /><br /> The backbone of the NWS Hydrologic Services is the issuance of river forecasts at over 4,000 locations. At these sites, the NWS issues forecasted river stage levels for the next five days. To run hydrologic models to support the issuance of these forecasts, the NWS must develop estimates of precipitation on a 4x4 km grid each hour. These quality controlled precipitation estimates are posted to the Internet for customers and the general public to use. <br /><br /> To complement river stage forecasts, the NWS also provides individualized hydrologic support to the emergency management community and other federal, state, and local water resource agencies. This support may take the form of customized hydro-meteorological briefings which can be disseminated through the web, telephone and/or chat services. In high impact events, the NWS may also station a hydrologist or meteorologist at a state or local emergency management office to provide a heightened level of support.
Identification of Streambank Erosion Processes and Channel Changes in Northeastern Mississippi
Year: Authors: Ramirez-Avila J.J., Langendoen E.J., McAnally W.H., Martin J.L., Ortega-Achury S.L., Diaz-Ramirez J.N.
Identification of streambank erosion processes is important for determining suitable measurement techniques and for choosing appropriate stream remedial measures. Sediment loads from watersheds located in Northeastern Mississippi can have contributions from stream channel degradation as large as 90%. Town Creek watershed is an experimental watershed in the Southeastern Plain Ecoregion of Mississippi (Ecoregion 65). Northern headwaters in Town Creek located within the Black Prairie Subecoregion present incised streams with unstable active bank profiles. The most common gravitational failure mechanisms are slab failure, soil fall, and cantilever failure, accompanied by a basal clean out process when stormflow events occur. An active agricultural land use near streambanks with limited or reduced presence of riparian zones increases the streambank instability and favors gully erosion activity. This condition is predominant along the different headwater reaches. The middle 20 km of the principal channel system is located within the transitional zone between the Tombigbee Hills and the Black Prairie subecoregions. Wide stable channels showing evidence of streambank erosion induced by fluvial erosion, shallow slides, and rotational failures are mixed with natural, vegetated zones and regions with sediment deposition on bed and streambanks. Especially along this section of the principal channel, sediment bed deposition and erosion are significantly modified seasonally by flow conditions. Low flow velocities and sediment deposition occur on the inside of incipient meander bends in the sinuous reach, along the downstream most 10 km before the outlet at the Tombigbee River.
Environmental Impact and Disposal of CCA-Treated Wood Waste
Year: Authors: Parker A.M., Bricka R.M.
Wood products are treated with preservatives to prohibit degradation by a multitude of organisms and to prolong the products’ life in adverse environments. The most widely used wood preservative since the early 1970’s has been chromated copper arsenate (CCA), resulting in nearly 80% of all treated wood products in North America being treated with CCA. In 2002 the wood preservative industry voluntarily adopted a restricted consumer use policy, and by late 2003 CCA-treated wood was limited to industrial applications due to concerns over possible exposure to toxic substances. Due to the restricted use policy, it is estimated that as much as 24 million tons of CCA may be available for disposal by 2020. Until recently, landfilling the out of service CCA-treated material was the accepted method of disposal. However, problems associated with soil and groundwater contamination, directly linked to the leaching of CCA-metals from landfills, have generated the need for a more effective and efficient disposal method for CCA-treated wood waste. Alternative approaches to CCA-treated wood disposal include utilizing advanced sorting techniques to place the treated wood waste in hazardous waste landfills, using chemical extraction to remove the CCA-metals, and employing thermochemical conversion processes to isolate the CCA-metals and reduce waste volume. This paper will provide detailed information on the environmental impact and disposal of CCA-treated wood waste, including environmental standards, test methods, and discussion of on-going research.
Life Cycle Assessment of Wood Pyrolysis for Bio-Oil Production
Year: Authors: Thomas H., Bricka R.M.
The Department of Chemical Engineering is evaluating a pyrolysis process for the conversion of wood into bio-oil or pyrolysis oil for use in wood treatment. Historically, wood has been treated with a mixture of copper, chromium, and arsenic. Due to the toxic substances and potential leaching into the ground water supply, CCA has been banned from use in the U.S. As older wood is being taken out of service, new methods of preservation are being explored for the wood being put into service. The resulting bio-oil from this pyrolysis process has shown promise as a wood preservative. <br /><br /> Before full scale production can begin a Life Cycle Assessment (LCA) will be performed on the process. LCA is a cradle-to-grave analysis involving the feedstock and materials of construction as well as storage, transportation, and disposal issues. It helps quantify emissions into the air and ground water. The results of the LCA model will be used to determine the economic viability of the process, the energy "break-even point," and the carbon footprint of the process. LCA can also be used to aid in future management and planning for the process.
Recycling CCA-Treated Wood Waste: Design and Operation of a Laboratory-Scale Pyrolysis System
Year: Authors: Cook M., Parker A.M., Bricka R.M.
Since the early 1970’s, the most widely used wood preservative has been chromated copper arsenate (CCA), resulting in nearly 80% of all treated wood products in North America being treated with CCA. By the end of 2003 CCA-treated wood was restricted to industrial applications, resulting in a considerable increase in the volume of CCA-treated wood slated for disposal. Landfilling was considered an acceptable means of discarding CCA-treated wood products until recently, as there have been instances of the toxic metals leaching from the landfills and contaminating the surrounding soil and groundwater. It is clear that traditional disposal methods are not adequate and that a safe and efficient disposal method for CCA-treated wood must be developed. <br /><br /> Fast pyrolysis, the heating of biomass at temperatures between 400°C and 650°C in the absence of oxygen, is a promising technology that can be applied to CCA-impregnated wood waste. Pyrolysis of lignocellulosic material produces char, liquid condensate (bio-oil), and non-condensing gases. The focus of this research is on removing the CCA-metals from the treated wood waste while recovering the energy value of the wood. This is accomplished by concentrating the CCA-metals in the bio-oil, for possible re-use in wood preservatives, during pyrolysis. A laboratory scale pyrolysis system, capable of operating in the desired temperature range under atmospheric and vacuum conditions, has been designed. The system is also designed to enable the collection of each pyrolysis product so that complete mass balances on the metals can be performed, tracking the fate of the CCA components. This paper discusses the process of designing and operating the laboratory scale pyrolysis system, as well as preliminary experimental results.
Electrokinetic Treatment of Mercury Contaminated Soil at the Mercury Refining Company Superfund Site
Year: Authors: Lusk R., Bricka R.M.
Mercury contamination due to leakage from industrial processes can result in serious environmental, health, and safety concerns. Traditional methods for the remediation of elemental mercury from contaminated sites include a dig and haul approach (retorting) and/or an isolation approach. However, these methods can be very costly and ineffective with regards to removing the mercury from the contaminated soil. Therefore, a new Electrokinetic Remediation method is proposed in which mercury can be cost effectively removed from a contaminated site in order to be recycled or disposed of properly. This method includes the use of anodes and cathodes installed in the ground throughout the contaminated site to produce an electric field which forces the contaminant to migrate to a specific position in which it can be efficiently removed. The use of several amendments to increase the solubility (and electrokinetic potential) of the mercury in the soil is also researched to determine a most effective and efficient mercury removal scheme. It was determined in batch and continuous electrokinetic cells that a 0.1 M Potassium Iodide, .01 M EDTA was effective in solubilizing and removing mercury below the EPA’s regulatory limit of 31mg/kg.
Evaluation of Phosphate Treatment Methods to Reduce Lead Mobility at Military Small Arms Training Ranges
Year: Authors: Bricka R.M., Blakely J.
The primary goal of the United States Military is to train and equip troops to maintain military readiness to defend the United States and its interests. Small arms range (SAR) training represents a major element in keeping the military ready to accomplish this mission. <br /><br /> Projectiles utilized as part of SAR training have accumulated in the soil at the SARs as a result of many years of use. These projectiles are composed of toxic metals. The projectiles, with weathering, change form allowing the metals to migrate to surface and ground water sources. Due to the toxicity associated with the metals, the SAR may pose a threat to humans and the environment. Current lead remediation techniques are costly and inefficient thus new cost effective remediation techniques must be developed and implemented. <br /><br /> Studies show that the treatment of the soil with phosphate-based binders may react with the metals, which results in lowering the solubility of the lead and other metals. The phosphate based-binders react with the metal ions, such as lead, to form insoluble metal phosphate complexes called pyromorphites as shown in equation 1.<br /><br /> 10M<sup>2+</sup> + 6H<sub>2</sub>PO<sub>4</sub><sup>- </sup> + 2OH<sup>-</sup> > M<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH<sub>2</sub>) + 12H+ Eq (1).<br /><br /> Several types of phosphate binders can be used to form the desired pyromorphites, however, the kinetics of the reaction depend on the phosphate complex. This may be due to the ability of the specific binder to mix efficiently in the contaminated soil or due to the reactive nature of the specific form of phosphate applied to the site. <br /><br /> This paper presents the results of a study to investigate the effect of phosphates on the lead contained in soils collected at military SAR training areas. Laboratory evaluations consisted of adding various phosphates at different dosages to SAR samples. After treatment the soils were subjected to a series of leaching tests. The result of laboratory effort as well as the planned field activities will be presented. <br /><br />
Possible Correlations Among Simple Visual Disturbance Estimates and Hydrologic and Edaphic Parameters in Forested Headwaters of Mississippi
Year: Authors: Dewey J.C., Ezell A.W., Palmer J.O., Choi B.
Silvicultural BMPs are designed to provide guidelines for maintaining the overall integrity of surface waters by minimizing non-point source inputs of sediment, nutrients and pesticides. Mississippi Forestry Commission guidelines for management of perennial and intermittent stream channels are specific; however guidance recommendations for ephemeral-flow channels are minimal albeit these flow channels are often incipient streams. Measuring the effects of disturbance due to silvicultural activities within and around ephemeral-flow channels on hydrology and soil quality is often time-consuming and cost-prohibitive. This project expands the scope of ongoing research that is currently characterizing the relationships among surface- and subsurface-hydrology, soil physical properties, vegetative communities, and sediment movement in ephemeral-flow and intermittent portions of incipient headwaters in Webster County, Mississippi. Hydrologic and edaphic monitoring began in January of 2007; timber harvesting was conducted in the 4th quarter of 2007; and the site was replanted with loblolly pine in the fourth quarter of 2008. The objective of this study is to characterize disturbance at multiple levels in hydrologically fluid headwater ephemeral areas using a simple visual classification scheme and determine whether correlations exist among observed disturbance levels, surface- and subsurface-hydrology, and selected soil properties.
Use of Borehole Geophysics to Determine Zones of Radium Production in Northern Arkansas
Year: Authors: Hart R.M., Kresse T.M.
Borehole geophysics can be used to identify zones of radium production and can aide in design of new well construction so that radium levels in new wells are minimized. Elevated radium levels in water from deep wells (average depth of approximately 2,000 feet) drilled into the Roubidoux Formation or Gunter Sandstone in northern Arkansas are an ongoing issue. Some wells drilled for public supply use have been abandoned because radium levels exceed the maximum contaminant level set by the U.S. Environmental Protection Agency. The U.S. Environmental Protection Agency has established a maximum contaminant level for combined Ra-226 and Ra-228 in public water supplies of 5 picocuries per liter. Radium levels (of about 6-7 picocuries per liter) in water samples from a public supply well near Hasty, Arkansas, exceed the maximum contaminant level.<br /><br /> Borehole geophysical methods are useful in determining physical and chemical properties of formations and groundwater in and around the well, in addition to aquifer hydraulic characteristics. A suite of geophysical logs that included flowmeter and natural gamma were recently completed by the U.S. Geological Survey Arkansas Water Science Center for a well near Hasty, Arkansas. These data were used to determine zones of flow into and out of the well, as well as the lithology near the flow zones. This information, combined with water-quality data, could provide insight needed to correlate specific lithology or fracture sets with radium levels.<br /><br /> Other wells in northern Arkansas contain elevated radium levels according to the Arkansas Department of Health. Zones of radium production will be evaluated in 3-5 of these identified wells to further correlate elevated radium with specific lithology or fracture sets. The identified lithology and fracture sets associated with the elevated radium can then be avoided or plugged in future well construction to minimize radium levels in those wells.
Using Human Specific Molecular Markers to Monitor Water Quality Along the Mississippi Gulf Coast
Year: Authors: Flood C., Carr M., Ellender R.D.
Our research examines the efficacy of using library independent methods and human specific marker to monitor the water quality of the Mississippi Gulf Coast. The two markers currently employed are <i>Methanobrevibacter smithii</i> and <i>Bacteroides</i> sp. <i>M. smithii</i> represents a methanogen that is commonly found in human feces and sewage. <i>Bacteroides sp.</i> are a major component of the intestinal flora in humans. Our goal is to examine the dynamic relationship of the physical and climatological variables that may influence the presence or absence of these markers in the natural environment. In the future, the inherent survivability of these markers will also be examined with relationship to water temperature, salinity, and turbidity. Temporal spatial relationships of the two markers are considered with respect to the presence or absence at certain collection sites. The collection sites mirror the sites monitored by MDEQ and represent an area of the coast that is commonly used for recreational purposes, but is also frequently closed due to high indicator counts. <br /><br /> An analysis of 12 months of coastal sampling contrasting the average enteroccoccal count at each sampling site, the percentage of times that the <i>M. smithii</i> marker appeared in each coastal sample, and the percentage of times that the <i>Bacteroides</i> marker appeared indicated that there was no statistical difference between the EN count and the percentages of either marker. In addition, there was a significant correlation between the percentage of <i>Bacteroides</i> and the percentage of <i>M. smithii</i> when all samples were grouped (0.9503). An analysis of the enteroccocal counts in creeks which drain into the beech environment revealed a significant difference between those coastal sites influenced by creek water versus those not influenced by creek water (P=0.0531). However, both the <i>M.smithii</i> and <i>Bacteroides</i> markers showed a positive correlation (0.7923) between creek versus non creek sites, demonstrating an apparent influence of the creek water on the presence or absence of the markers in coastal waters.
Water Quality of Least-Impaired Lakes in Eastern and Southern Arkansas
Year: Authors: Justus B.G.
A three-phased study identified one least-impaired (reference) lake for each of four Arkansas lake classifications; three classifications in the Mississippi Alluvial Plain (MAP) ecoregion and a fourth classification in the South Central Plains (SCP) ecoregion. Water quality at three of the least-impaired lakes generally was comparable and also was comparable to water quality from Kansas and Missouri reference lakes and Texas least-impaired lakes. Water quality of one least-impaired lake in the MAP ecoregion was not as good as water quality in other least-impaired lakes in Arkansas or in the three other States; a probable consequence of all lakes in that classification having a designated use as a source of irrigation water. Chemical and physical conditions for all four lake classifications were at times naturally harsh as limnological characteristics changed temporally. As a consequence of allochthonous organic material, oxbow lakes isolated within watersheds comprised of swamps were susceptible to low dissolved-oxygen concentrations to the extent that conditions would be limiting to some aquatic biota. Also, pH in lakes in the SCP ecoregion was < 6.0, a level exceeding current Arkansas water-quality standards but typical of black water systems. Water quality of the deepest lakes exceeded that of shallow lakes. N:P ratios and trophic state indices may be less effective for assessing water quality for shallow lakes (<2m) than for deep lakes because there is an increased exposure of sediment (and associated phosphorus) to disturbance and light in the former.
Evaluating the Role of Groundwater and Surface-Water Interaction on the Transport of Agricultural Nutrients to the Shallow Alluvial Aquifer Underlying
Year: Authors: Barlow J.R., Dalton M.S., Coupe R.H.
Between April 2007 and November 2008, the U.S. Geological Survey (USGS) has collected various hydrogeologic and water-quality data to evaluate the role of groundwater and surface-water interaction on the transport of agriculturally applied nutrients to the shallow (less than 25 feet deep) sand and gravel aquifer underlying the Mississippi Alluvial Plain in northwestern Mississippi. Despite stringent best management practices, agricultural activities seemingly contribute to nutrient and pesticide loads in the region’s groundwater and surface waters. A pervasive, near-surface, semi-impermeable clay layer appears to substantially inhibit movement of nutrients into the shallow alluvial aquifer. However, many streams and ditches are incised below the clay layer into more permeable material, thus suggesting another, more direct route for nutrient transport into the underlying alluvial aquifer. Such transport would be further enhanced by declining water levels in the aquifer. Previous investigations by the USGS showed that during periods of high surface-water flow, groundwater flow reverses direction, and the stream changes from a gaining stream (groundwater flow into the stream) to a losing stream (surface-water flow into the streambed sediments and potentially into the shallow alluvial aquifer). A one-dimensional model developed for the investigations considered only the movement of water in the vertical direction (into and out of the streambed). The present investigation expands on the previous model by evaluating both the vertical and horizontal flow components and couples this information with water-chemistry data.
Management of an Abandoned River Channel Wetland for Mitigation of Nonpoint Source Pollution
Year: Authors: Shields Jr. F.D., Wilson C.N., Bryant C.T., Testa III S.
Reduction of nonpoint source pollutants, principally sediment and nutrients moving from cultivated fields to surface waters, is a major challenge. Remnants of once-extensive natural wetlands occur across the agricultural landscape, and some workers have suggested that these areas might be managed to yield improved wetland function in terms of trapping and retention of nonpoint source pollutants. An existing wetland in a severed meander bend cut off in the 1940s from the Coldwater River in Tunica County, MS was modified by the construction of weirs equipped with water control structures. The wetland was a segment of old river channel about 500 m long and 14 m wide. Inputs to the wetland cell included sporadic flows due to runoff events from about 350 ha of cultivated fields and less frequent but larger flood events from the river. This type of flood event occurred only once during the study. <br /><br /> Weir drainage structures were operated to retain water during March—November, and were opened to allow flow to and from the Coldwater River during December, January and February. Weir elevation during March—November corresponded to a mean water depth of ~ 0.15 m. Volumes of water entering and leaving the wetland cell were estimated for 18 months using measurements made at weirs and at a culvert. Estimates of loads entering and leaving the wetland cell were computed based on concentrations of grab samples collected at the wetland cell inflow and outflow locations. <br /><br /> Water concentrations of sediment and nutrients were generally lower at the downstream end of the wetland cell than in the major inflow, an ephemeral slough. Mean values of turbidity, suspended sediment concentration, and concentrations of filterable and total phosphorus were 25% to 40% lower at the wetland cell discharge weir than in the slough. Mean concentrations of ammonia were 38% lower, but mean nitrate and nitrite concentrations were essentially unchanged by the wetland cell. Comparison of estimated input and output loads during periods when the wetland cell was not flooded by the river indicated that the wetland cell retained about 18% of input suspended sediment, 24% of phosphorus, and 29% of nitrogen input from cultivated fields. Wetland cell sediment and nutrient retention efficiency was greater for drier months, and declined during wetter periods with frequent runoff events.
Methyl Mercury in Water and Fish Tissue in the Lower Yazoo Basin
Year: Authors: Myers K.
Mercury is a leading cause of fish consumption advisories in the United States and is the only metal with a fish consumption advisory in Mississippi. While none of the affected water bodies are within the Mississippi Delta, a 2001 ambient water quality criterion established by the EPA would lower Mississippi’s fish tissue threshold from 1 mg mercury per kg of fish tissue to 0.3 mg methyl mercury per kg of fish tissue. Since studies have shown that nearly 100 percent of the mercury that bioaccumulates in predator fish tissue is methyl mercury, the new fish tissue criterion would become 0.3 mg/kg mercury in fish tissue. The State of Mississippi is expected to implement this new fish tissue mercury criterion within the next year. Implementation will increase the number of water bodies with fish tissue consumption advisories within the State and the Mississippi Delta in particular. Recently the USACE Vicksburg District analyzed the potential for increases in methyl mercury concentrations in surface water and fish tissue based upon completion of the Yazoo Backwater Project’s reforestation component. The analysis used a simplified linear model that compared the potential for changes in methyl mercury production based upon changes in land use, flooded acres, and flood duration. The model predicted that completion of the Yazoo Backwater Project recommended plan and reforestation of up to 55,600 acres of currently farmed agricultural land could have increased methyl mercury production by 3 percent over base conditions. The Vicksburg District’s mercury database includes surface water samples for methyl mercury collected between 2003 and 2008 and mercury in fish tissue samples collected between 1993 and 2008. Surface water samples were collected during flooded conditions in Delta National Forest greentree reservoirs, during flood and non-flood conditions in Delta Nation Forest wetlands, and during summer, non-flood conditions in streams and lakes in the lower Yazoo Backwater Area. The data show that methyl mercury production is highest in areas rich in easily accessible organic matter that undergo extended flooding. Fish tissue mercury concentrations appear to be related to flood duration and the number of acres flooded.
Effects of Transgenic Glyphosate-Resistant Crops on Water Quality
Year: Authors: Cerdeira A.L., Duke S.O.
Glyphosate (N-[phosphonomethyl] glycine) is a highly effective, non-selective herbicide. Herbicide-resistant crop (HRC) has been the most successful trait used in transgenic crops throughout the world. Transgenic glyphosate-resistant crops (GRCs) have been commercialized and grown extensively in the Western Hemisphere and, to a lesser extent, elsewhere. GRCs have generally become dominant in those countries where they have been approved for use, greatly increasing the utilization of glyphosate. Potential effects of glyphosate on ground and surface water are lower than the effects of the most herbicides that are replaced when GRCs are adopted. Perhaps the most positive indirect effect is that GRCs crops promote the adoption of reduced- or no-tillage agriculture, resulting in a significant reduction in soil erosion and water contamination. Glyphosate and its degradation product, aminomethylphosphonate (AMPA), residues are not usually detected in high levels in ground or surface water in areas where glyphosate is used extensively. There are some concerns about AMPA in water since it has higher mobility and persistence in the environment than glyphosate. However, neither glyphosate nor AMPA are considered to be significantly toxic. Of greater concern are the formulation ingredients, which can vary from country to country, from product to product, and even over time with the same product. There is some published evidence that formulation ingredients might adversely affect amphibians in some situations.
A Study of Seagrass, <i>Ruppia maritima</i> and <i>Halodule wrightii</i>, at Grand Bay National Estuarine Research Reserve
Year: Authors: Nica C., Cho H.J.
Seagrass beds provide nursery and foraging habitats for marine life, help improve water clarity, help reduce coastal erosion, and buffer wave energy. Therefore, temporal changes in their distribution and abundance indirectly reflect changes in the habitat quality and environmental health status. <i>Ruppia maritima</i>, the most abundant and common species in the Mississippi seagrass beds, is an opportunistic, pioneer species that is highly dependent on sexual reproduction. In order to provide information needed to identify areas that can support seagrass growth and to understand the temporal variations in the seagrass structures within the areas, we conducted biannual surveys at <i>Ruppia maritima</i> and <i>Halodule wrightii</i> beds in Grand Bay National Estuarine Research Reserve (NERR), Mississippi. We hypothesized that there were significant spatial and short-term fluctuations in the coverage of Ruppia/Halodule beds. Three-way ANOVA was used to analyze seagrass depth distribution and abundance, which we surveyed along water depth gradients and shoreline orientation. Other pertinent water quality parameters - turbidity, [chlorophyll a], dissolved color, dissolved oxygen, pH, salinity, temperature, sediment, nutrients, and water level were monitored in-situ or obtained from the NERR monitoring data. The coverage and distribution of the beds dominated by <i>R. maritima</i> and the <i>Ruppia—Halodule</i> mixed beds of the tidal bay area (the estuarine area) in the reserve vary substantially primarily due to changes in <i>R. maritima</i> abundance between summer and fall. Our results on site variation in SAV coverage suggest that shore orientation and wind-driven energy within the estuarine system might be contributing factors to the spatial difference in the shallow estuary. The estuarine <i>Ruppia</i> population that grows in the shallow, high wave energy environment has an annual growth pattern: seedling growth in early spring, rapid vertical growth in April, producing abundant inflorescence and seeds in May and June, and senescence in the fall. On the other hand, <i>R. maritima</i> that occurs in the bayous and marsh in the reserve area, where tides and wind-driven wave actions are less severe, rarely flowers and sets seeds. Our results also suggest that consistent SAV survey efforts are needed to reduce errors in assessments of disturbance/restoration impacts and long-term trend, which will provide a useful tool for management and research.
Influences of Land Surface Characteristics on Precipitation over the Lower Mississippi River Alluvial Plain
Year: Authors: Dyer J.
The lower Mississippi River alluvial valley, covering sections of Mississippi, Arkansas, and Louisiana, is well recognized as a major agricultural center of the US. The region is characterized by extremely fertile soils deposited through repeated flooding of the Mississippi River; therefore, a large portion of the area is cultivated. Since roughly 1940, land use, vegetation, and soil characteristics have remained relatively consistent over the area, with irrigation levels increasing in association with crop density. Research has shown that agriculture can have an influence on regional weather variability through land use, soil type, and vegetation patterns by influencing energy and moisture transport into the atmospheric boundary layer. Due to the relatively sharp contrasts in these surface characteristics between the alluvial valley and surrounding regions, it is suspected that anthropogenic weather modification may be occurring in the form of enhanced mesoscale convective circulations. These circulations are most evident during the warm season when radiational surface heating is greatest and synoptic-scale forcings are minimal, and can have a direct influence on agriculture by varying the intensity and distribution of convective precipitation. The purpose of this project is to define and quantify the location and intensity of convective boundaries and associated precipitation over the lower Mississippi River alluvial valley. This will aid water resource managers and meteorological forecasters in recognizing the relative climatological patterns of rainfall during the growing season, and will provide information on the influence of anthropogenic land use and soil moisture boundaries on precipitation distribution. Initial results from the study indicate an eastward shift in warm-season precipitation relative to predominantly agricultural areas, such that rainfall is minimized over the lower Mississippi River alluvial valley and maximized directly eastward along the Hwy. 45 corridor. Although there are a number of factors that combine to generate this pattern, it is expected that enhanced soil moisture and latent heat flux due to heavy irrigation over the alluvial plain may play an important role in generating more intense convective boundaries over the region, leading to increased downstream transport of atmospheric moisture and subsequent precipitation.
Simulated Solute Transport and Shallow Subsurface Flow in Northwestern Mississippi
Year: Authors: Rose C.E., Nimmo J.R., Perkins K.S., Coupe R.H.
Solute transport and subsurface flow through a Sharkey Clay soil typical of a soybean field in the alluvial plain of northwestern Mississippi were simulated using the two-dimensional, variably-saturated flow model of solute transport (VS2DTI) developed by the U.S. Geological Survey. The model was developed and validated using data collected from a 2-m ring infiltration test, which include: calcium bromide (CaBr) concentrations at depth, water flux, and soil moisture content. Local and State agencies are attempting to develop a plan for sustainable use of the Mississippi River Valley alluvial aquifer, which is heavily pumped for irrigation and has documented water-level declines of tens of feet in some areas over time. A critical component to determining the sustainable yield of the aquifer is recharge, both the amount and source. The most recent groundwater model simulation by the U.S. Geological Survey in 2001 estimated that about 5 percent of precipitation recharges the alluvial aquifer annually; more localized studies found that number is as high as 17 percent. Due to the complexity of recharge processes, a tool for local estimation of recharge is necessary. In this study, simulated results, using VS2DTI, were compared to observed infiltration rates along with flow direction and extent of the CaBr tracer. Observed tracer concentrations and flow were found to be more spatially variable than simulated solute transport and subsurface flow. This suggests flow in the vadose zone is not only dependent on the medium of soil and its physical properties, but also on anisotropic anomalies, such as capillary or layer barriers, or mudcracks and large organic particles, which can produce preferential flow pathways.
Protecting Water Quality in Your Community
Year: Authors: Roberts C.D.
Most of us would prefer to ignore sewage. Rarely do we discuss what happens to water after it exits our homes through toilets, sinks, and showers. Yet, it has important ramifications for the rivers and streams that we love. Fresh, clean water is a human right and serves as the lifeline of the earth’s ecosystems. Not only do we drink water, we use it for cooking, cleaning, recreation, fishing, transportation, and commerce. All those uses are jeopardized when surface water is polluted by sewage. <br /><br /> In order to help Gulf residents recognize and address sewage pollution problems in their streams, bayous, and lakes, the Gulf Restoration Network produced <i>Our Water Our Health, A Citizen’s Guide to Sewage Pollution</i> manual and training seminar. The basics of the training include sewage 101, documenting a problem, commenting on permits, how to run a public campaign for clean water, messaging techniques, how to set up a press conference, and many other skills and knowledge based modules. The manual reviews topics such as: how sewage treatment works, law and policy of wastewater, what types of pollution come from sewage treatment plants, how to identify problems in your local water supply, and the basics of how states grant permits to sewage treatment plants. After attending this training, participants will be able to successfully advocate for better wastewater treatment, utilizing tools such as coalition building, media, and the Clean Water Act!
The Mississippi Embayment Regional Aquifer Study (MERAS)—Model Construction, Simulation of Groundwater Flow, and Potential Uses of a Regional Fl
Year: Authors: Clark B.R., Hart R.M.
The U.S. Geological Survey (USGS) Groundwater Resources Program supports projects to determine groundwater availability in multiple areas across the United States. One project is the Mississippi Embayment Regional Aquifer Study (MERAS). The primary tool used to evaluate groundwater availability in the embayment is the MERAS groundwater flow model. The construction of the MERAS model, using the USGS MODFLOW-2005 modeling software, included 2,700 geophysical logs for hydrogeologic framework development; 137 years of groundwater withdrawal information; 70,000 groundwater withdrawal locations; 39 rivers comprising 6,900 river miles; and precipitation, land use, surficial geology, and aquifer properties covering 78,000 square miles. Model calibration data include 55,000 ground-water level observations and streamflows at 14 stream-gage locations. <br /><br /> The MERAS model simulates groundwater flow from 1870 to 2007 and has been used to project impacts of climate variability on groundwater flow to the year 2037. Values of root mean square error between simulated and observed hydraulic heads of all observations up to 2007 ranged from 12.23 ft in 1919 to 48.19 ft in 1951. The MERAS model has been used to simulate climatic effects on the groundwater flow system by changing precipitation and streamflow input values based on projections of historic climate data analysis. Preliminary results of the groundwater flow model indicate deepening cones of depression over the next 30 years in the Mississippi River Valley alluvial aquifer in the northern part of the embayment.<br /><br /> Local stakeholders may also benefit from the use of additional MODFLOW-2005 methods and processes in conjunction with the MERAS model; the Local Grid Refinement (LGR) method and the Groundwater Management (GWM) process can provide excellent information for the local water manager. Potential use of the LGR method allows for more finely discretized local-scale areas to be simulated within the embayment while using the MERAS model as a boundary which contributes or receives flow. The GWM process allows for the optimization of groundwater pumpage given constraints such as drawdown, water level, and streamflow. These types of analyses with LGR and GWM can be particularly useful in areas where intense pumping stresses the groundwater- surface water system by lowering groundwater levels, reducing base flow, and ultimately inducing leakage from surface water bodies to the groundwater system. In a broader sense, the GWM process might be used in a regional application to evaluate issues related to resource sustainability on an intrastate or interstate scale.
Water quality in the Coldwater River Basin: Comparing traditional measures of water and habitat quality to index of biotic integrity findings.
Year: Authors: Tietjen T., Ervin G.N.
The US Army Corps of Engineers in conjunction with the Mississippi Department of Environmental Quality has worked to determine the quality of water in the streams of the Mississippi Delta region using an Index of Biotic Integrity (lBI) approach. This approach to water quality monitoring seeks to use information extracted from fish community composition and habitat parameters to provide an integrated and comprehensive picture of water quality that is reported to be superior to traditional grab samples analyzed for chemical water quality parameters. We have been working to collect water samples from a subset of these sampling sites and analyzing this water using traditional measures of water quality. These samples have been analyzed for a variety of chemical (Nitrite+Nitrate-Nitrogen, Ammonium-Nitrogen, Soluble Reactive Phosphorus, Oxygen, pH), biological measures (Total Coliform bacteria, Fecal Coliform bacteria, Chemical Oxygen Demand), and physical measures (suspended sediments, temperature). We compared these data sets by examining correlations between IBI scores and quantitative measures ofwater quality. This approach did not help substantiate the value ofthe IBI approach or provide guidance for mitigation and restoration activities that likely would benefit these streams.
Multi-scale evaluation and analysis of precipitation patterns over the Mississippi Delta
Year: Authors: Dyer J.
The Mississippi River floodplain in northwestern Mississippi, often referred to as the Mississippi Delta, is extremely important for regional economic stability and growth due to the widespread agriculture in the area. The region is unique in that there are currently three sources of precipitation measurements available: (l) radar-derived precipitation estimates from National Weather Service (NWS) NEXRAD network, surface observations from NWS recording stations, and surface observations from US Department of Agriculture (USDA) Soil Climate Analysis Network (SCAN) recording stations. In terms of water resource management and climatological precipitation research, quantitatively defining the biases associated with available precipitation data sources is critical in choosing which source to use for a given application. Additionally, due to the importance of precipitation in agriculture along with recent drought in the Mississippi Delta region, precipitation patterns should be reevaluated in terms of duration frequency, and extent. The inclusion of long-term data from surface gages along with shorter-term but higher resolution radar-derived rainfall estimates allow for a detailed analysis of past and current precipitation trends. This will lead to a better understanding of rainfall trends and patterns and potentially better prediction of future rainfall.
A continuation of climatological and cultural influences on annual groundwater decline in the Mississippi Delta shallow alluvial aquifer: Modeling p
Year: Authors: Wax C.L., Pote J., Massey J.
Water use from the delta aquiter, contributed as in-kind contribution to the project by the Yazoo-Mississippi Delta Joint Water Management District, has been quantified by crop, acreage, and irrigation method. A relationship between growing season rainfall and irrigation water use has been developed to link interannual variations in water use to variations in climate (rainfall). Water use coefficients have been developed to link each specific type of irrigation on each crop type with a water use amount in acre feet per acre. A complete prototype water use model has been completed using acreages, irrigation methods, and management strategies in place during 2006 in Sunflower County to predict annual water demand for cotton, rice, soybeans, corn, and catfish. Figure 1 shows the inputs and the resulting estimate of annual water use for Sunflower County. The model is constructed in an Excel spreadsheet. The interactive model file is sent as a separate file along with this report.
Water Quality Trading: Is it Realistic for the Mississippi River?
Year: Authors: Showalter S.
Although significant progress has been made since passage of the Clean Water Act in 1972, the stated Congressional goal of assuring that all waters are "fishable/swimmable" remains elusive. Traditional "end-of-pipe"pollution-control measures must be supplemented with new policies to diffuse sources of pollution such as stormwater and agricultural runoff. One such innovative policy is water quality trading. In December 2006, the State of Pennsylvania joined ten states that currently have some form of a water quality trading program by approving a state administrative policy to allow point sources to offset pollution discharges by purchasing "credits" from other facilities or farmers. Similarly, in August 2008, the Florida Department of Environmental Protection proposed regulations to establish procedures for water quality trading, and. trading programs also are in development in Minnesota, West Virginia and Maryland. In selecting ten finalists for its "Targeted Watershed Grants" on water quality trading this past December, the U.S. Environmental Protection Agency (EPA) is encouraging states along the Mississippi River to consider implementing trading programs to address the hypoxia, or low oxygen levels, in the Gulf of Mexico. Nonetheless, the courts have not reached consensus on whether the Clean Water Act allows point sources to offset discharges into impaired waterbodies, or waters failing to meet state water quality standards. For example, in Friends of Pinto Creek v. EPA, 504 F.3d 1007 (9th Cir. 2007), the Ninth Circuit sided with an environmental group claiming that the EPA’s authorization of upstream remediation to offset a company’s copper discharges into the impaired Pinto Creek violated the Clean Water Act. This presentation will analyze the existing state water quality trading programs in light of the legal and scientific issues that may arise as states in the Mississippi River Basin consider implementing such programs.
Watershed Assessment and Education
Year: Authors: Silitonga M., Johnson A.
The Coles Creek Watershed, located in the southwestern quadrant of the state of Mississippi, is listed under the US EPA impaired water section 303(d). Degradation of the ponds/lakes and streams/creeks in this watershed is caused mostly by biological impairment, followed by nutrients, organic enrichment or Low Dissolved Oxygen, sediment/ siltation, pesticides, and pathogens (US EPA, 2007). Water samples will be collected from waterbodies in the Coles Creek watershed for physical, chemical, and biological analysis. Sampling will be conducted every month over a 12- month period to evaluate the spatial and temporal variability of water quality. Positions of sample locations will be geo-referenced to be displayed on a map using ArcView. In addition, soil and rainfall data will be used to study the correlation between land-use and water quality. The analysis of the results will help us to better understand the quality of water in the watershed. Results will also help us to determine the best alternative management practice(s) to be adopted and implemented in the community. Based on the results and findings, educational materials will be developed and disseminated to the communities. This effort will help increase the community awareness of their environment and encourage them to adopt and implement BMPs on their land which will lead to promoting environmental health and its sustainability, thereby, having good water quality to support the economic development in the area.
The Oklahoma Water Bank Project
Year: Authors: Hurt K.
The Arbuckle Simpson aquifer is located in south central Oklahoma. Although it is a highly productive karst aquifer that provides a crystal clear supply of groundwater to a multitude of springs and streams in the area, it has relatively limited storage. As such, frequent recharge events are necessary to maintain spring flows, base flows in area streams and water levels in area wells. Development of the local area and reliance on groundwater and spring water for municipal supplies has resulted in increased depletion rates during drought periods such as the extreme 2005 –2006 period. However, during 2007, the area experienced multiple flood events that caused millions of dollars of damage to homes, property and businesses. <br /><br /> This back to back occurrence of damaging droughts and floods set the stage for local leaders, scientists and regulators to write legislation supporting the Arbuckle Simpson Water Bank project. The project is designed to divert surface water captured by upstream flood control structures (i.e., NRCS watershed lakes) to the subsurface during flood events. This management approach allows the refilling of aquifers with damaging floodwater that downstream users do not desire. In a sense it turns flood lemons into drought lemonade. The partners on the project include the City of Ada, OK, the Chickasaw Nation, the Oklahoma State Climatologist, the Oklahoma Water Resources Board, the Oklahoma State Legislature, the National Weather Center, the National Severe Storms Lab, the Oklahoma Department of Environmental Quality, the Oklahoma Conservation Commission, the Bureau of Reclamation, University of Oklahoma and Oklahoma State University. The project was recently selected as the winner of the 2009 Secretary of the Interior’s "Partners in Conservation" award. <br /><br /> This presentation will include information on cutting edge technology used to predict, measure, manage and recharge water, including: <ul><li>Advanced radar systems,</li> <li>Mesonet meteorological stations,</li> <li>Passive filtration systems,</li> <li>Engineered recharge zones,</li> <li>Computer modeling of predicted water supply inventories,</li> <li>Web based information sharing.</li></ul>
Molecular Identification of Pentachlorophenol (PCP) Tolerant Bacterial Communities in Contaminated Groundwater
Year: Authors: Stokes C.E., Prewitt M.L., Borazjani H.
Pentachlorophenol (PCP), a highly toxic and recalcitrant wood preservative, contaminates groundwater aquifers in many areas of United States. Improper handling, storage, and disposal practices in the past have led to the contamination of groundwater at many wood treatment facilities. Biosparging, the injection of clean air and nutrients under pressure into the groundwater system, has emerged as a viable in-situ treatment option for removal of this type of contamination. Previous studies in this area have relied on growth media cultures for isolation and identification of the bacterial community that is responsible for the degradation of the pollutant. However, molecular identification of DNA extracted from the contaminated groundwater will provide a more accurate description of the microbial community. Seven biosparging wells located at a wood treatment facility with a PCP groundwater contamination in central Mississippi have been monitored since 2001. Groundwater samples from these existing wells were taken quarterly and examined for total PCP concentration. DNA was extracted from these water samples using a WaterMaster DNA purification kit. The 16s region from this DNA was also amplified using bacterial specific primers and then cloned into <i>E. coli</i> cells. Cloned <i>E. coli</i> cells were extracted and sequenced for identification. The goals of this research were to identify the most PCP-tolerant bacterial communities and to determine the PCP tolerance limits of these bacterial communities.
Composition and Size Distribution of Colored Dissolved Organic Matter in River Waters as Characterized Using Fluorescence EEM and Flow Field-Flow Frac
Year: Authors: Zhou Z., Stolpe B., Guo L.
Colored dissolved organic matter (CDOM) is an active organic component in natural waters, and can have an effect on environmental and water quality in aquatic systems. In order to examine the composition and size-distribution of CDOM in the Mississippi and Pearl rivers and the effect of flooding, monthly water samples and flood samples were collected from the lower Mississippi River at Baton Rouge and the Pearl River at Stennis Space Center, followed by size fractionation using ultrafiltration and flow field-flow fractionation (FlFFF) and measurements of dissolved organic carbon (DOC), specific UV absorbance (SUVA) and fluorescence excitation emission matrix (EEM). Concentration of DOC varied from 2.8 to 3.9 mg-C/L in the Mississippi River, but was much higher in the Pearl River, ranging from 3.9 mg-C/L in Mar-2009 to 13.6 mg-C/L during the Apr-2009 flood event. Average value of SUVA (254 nm) was 0.035±0.003 L/mg-C/cm in the Mississippi River and 0.045±0.006 in the Pearl River. In the Mississippi River the SUVA<sub>254</sub> was fairly constant, indicating similar DOM sources between seasons, while the SUVA<sub>254</sub> in the Pearl River varied with DOC concentration and discharge, indicating variable DOM composition. Colloidal organic matter (1-450 nm) from the Pearl River had a SUVA<sub>254</sub> value of 0.889 compared to 0.0029 for the <1 nm dissolved fraction, showing that CDOM is mostly present in the colloidal fraction and enriched in microbially-derived humic substances (SUVA at 370 nm). The colloidal size spectra of CDOM determined by FlFF with UV absorbance detection show that the majority of CDOM is found in a population of small (1-4 nm hydrodynamic diameter) colloids in both rivers although the relative proportions of CDOM in the range of 1- 4 nm, 4-20 nm, and >20 nm varied between samples. Fluorescence index (FI), which is the ratio of the emission intensity at 450 nm to that at 500 nm under excitation of 370 nm, shows a more terrestrially derived CDOM in the Pearl River (1.29-1.36), but more microbially derived CDOM in the Mississippi River (1.47-1.49). Based on the integration of fluorescence intensity in the FlFFF fractograms, the ratio of DOC-normalized protein-type fluorophores (Ex/Em 276/340 nm) (proFL/DOC) and humic-type fluorophores (Ex/Em 350/450 nm) (humFL/DOC) exhibits more amino-acids and humic-substance components of CDOM in the Pearl River (7.7-16 and 1.0-3.6) than in the Mississippi River (6.5-9.4 and 0.2-1.3). Moreover, the humFL/DOC value during flooding in the Pearl River was three times higher than normal sample values, suggesting more humic substances during the flooding event. In the EEM measurements, the Ex/Em wavelength at maximum fluorescence intensity shifted from 330/445 nm in normal samples to 338/451nm in flood samples, suggesting an increased input of humic substances that are less transformed by photochemical or microbial processes during the flooding event in the Pearl River. The SUVA and fluorescence EEM coupled with FlFFF and ultrafiltration can be used to effectively investigate the source and composition of CDOM in natural waters.
Ground Water-Surface Water Interaction in the West-Central Delta (Washington County)
Year: Authors: Parrish P.C.
From the end of the 2008 irrigation season to the beginning of the 2009 irrigation season, measurements were made at eleven Mississippi Delta irrigation wells. The measurements were made along a profile in Washington County. This profile extended from the Longview community to just west of Hollandale, MS. All of the wells lie on a general West to East trend. <br /><br /> The purpose of this study was to evaluate the interaction between surface water of the Mississippi River and ground water of the Mississippi River Valley Alluvial Aquifer (MRVA) along a specific profile. The study also allowed for pinpointing of the localized ground water divide. Data from 2008-2009 was then compared to data from a 1992-1993 study along the same profile. The question that must be asked is whether the ground water divide and the Mississippi River’s influence shifted over the last 15-16 years. If the answer is yes, then more study will be needed to determine if this is localized and to determine what factors may have contributed to the shift.
Development of Water Correction Algorithm for Underwater Vegetation Signals
Year: Authors: Cho H.J., Lu D., Washington M.
The unique spectral characteristics of green vegetation, low reflectance in red and high reflectance in Near-Infrared (NIR), have been used to develop vegetation indices, such as Normalized Difference Vegetation Index (NDVI). Our preliminary studies suggest that NDVI was not a useful indicator for submerged aquatic vegetation (SAV), even in clear water, due to energy absorption by water in the NIR region. In order to improve the use of the vegetation indices, we modeled the depth-induced water absorption and scattering through a controlled indoor experiment. We used a GER 1500 spectroradiometer to collect spectral data over an experimental water tank (70cm tall, 50cm wide) that was deployed with a black panel or a white panel at a time; the panels were cut to fit the bottom of the tank. Our assumptions were: (1) the black bottom panel absorbs 100% incoming light; (2) the white bottom panel reflects 100% incoming light; and (3) the water volume scattering and absorption remains the same for the two conditions (black and white bottoms) at a given depth. The measured upwelling radiance was converted to % reflectance. We developed correctional algorithms for water scattering and absorption using the reflectance data. After finding the contribution of these features, we were able to remove the water effects from the measured data. The SAV reflectance that was corrected using the algorithm produced a spectral signature more closely resembling those of terrestrial vegetation. The application of the algorithm significantly improved the vegetation signals, especially in the NIR region. Our results suggest the conventional NDVI: (1) is not a good indicator for submerged plants even at shallow waters (0.3 m); and (2) the index values can significantly improve once the water effects are modeled and removed.
Sequence Stratigraphy, Depositional Systems and Ground-Water Supply
Year: Authors: Dockery III D.T.
Ground-water supplies in the state’s Tertiary, Late Cretaceous, and even Paleozoic aquifers are not all evenly distributed. Many (and some of the most prolific) are concentrated in valley-fill deposits created during times of low sea level and in the channels of fluvial and deltaic systems that formed during sea-level lowstands and sea-level highstand-regressive intervals. Examples of such linear and lenticular water-supply sands include: (1) valley-fill sands in the Tuscaloosa Formation, (2) valley-fill sands in the basal Clayton Formation, (3) valley-fill sands in the Coal Bluff Member of the Naheola Formation (lower Wilcox aquifer), (4) valley fill sands in the Gravel Creek Sand Member of the Nanafalia Formation (lower Wilcox aquifer), (5) valley-fill sands in the basal Tuscahoma Formation (middle Wilcox aquifer), (6) highstand-regressive channel sands in the lower Hatchetigbee Formation (upper Wilcox aquifer), (7) valley-fill sands in the Meridian Sand (upper Wilcox aquifer), (8) highstand-regressive channel sands in the Kosciusko Formation (Sparta Aquifer), (9) highstand-regressive channel sands in the Cockfield Formation, (10) valley-fill sands in the Forest Hill Formation, (10) valley-fill sands in the Waynesboro Sand, (11) valley fill sands in the basal Catahoula Formation, (12) valley-fill sands in the Citronelle Formation and other high-level terrace deposits, and (13) valley-fill sands in the Mississippi River Alluvium (Alluvial aquifer).<br /><br /> There are two major drainage systems responsible for most of the valley-fill and fluvial/deltaic-channel deposits, which serve as aquifers for ground-water supplies in Mississippi. The first is an ancient drainage basin with an Appalachian source, which is often referred to as the ancestral Tennessee River. This ancient river system is responsible for valley-fill gravels and sands of the Tuscaloosa Formation in northeastern Mississippi and for the vein-quartz and heavy minerals in the state’s Tertiary and Quaternary gravels and sands. The second drainage basin drained a portion of the North American mid-continent and is referred to as the ancestral Mississippi River. This river system has been credited for fluvial sands as old as the Late Jurassic sandstones in the Smackover Formation in west-central Mississippi. It is certainly responsible for those Late Cretaceous and Tertiary formations that thicken along the axis of the Mississippi Embayment as well as the Pliocene gravels of the Citronelle Formation in west-central Mississippi and the perched Early Pleistocene pre-loess gravel deposits below the loess along the eastern Mississippi River valley wall, extending from Tennessee to Louisiana.
Monitoring and Statistical Analysis of Fecal Indicator Bacteria in Lower Sardis Lake, Mississippi
Year: Authors: Surbeck C.
The quality of a recreational water body is usually assessed by quantifying fecal indicator bacteria (FIB) in the water. FIB are groups of bacteria that together may indicate the presence of pathogens and have been strongly correlated with diseases contracted by swimmers in recreational waters. A two-week monitoring event was conducted in the summer of 2008 at 10 locations in the Lower Sardis Lake in northern Mississippi. Samples at selected beaches and embayments were collected and analyzed for total coliforms, <i>E. coli</i>, temperature, dissolved oxygen, nitrate, phosphate, and phenols. Concentrations of the FIB <i>E. coli</i> were generally below the U.S. Environmental Protection Agency (EPA) criterion of 126 per 100 mL for swimming freshwaters, which is consistent with previous research that attributes high FIB concentrations to large urban centers and not rural areas, such as the field location of this study. However, higher concentrations than the EPA criterion were found in lake water near a residential area and at an embayment with presence of wildlife. Further, results from creek sampling at a nearby town indicate consistently high <i>E. coli</i> concentrations at a geometric mean of 424 per 100 mL. Given the incidences of higher than standard FIB concentrations, statistical analyses were conducted to relate FIB concentrations to days of high-swimmer visits, presence of nutrients, and location.
Anthropogenic Chemicals in the Source and Finished Water From Three Mississippi Communities That Use Surface Water as Their Drinking-Water Supply
Year: Authors: Rose C.E., Coupe R.H., Smith C.M.
The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, began a sampling program in the fall of 2007 to analyze water samples for a suite of wastewater indicator compounds and pesticides for the three drinking-water facilities in Mississippi that use surface water from the Pearl, Tombigbee, and Tennessee Rivers as their source water. Three samples, from both source water and finished water, were collected from each facility in October 2007, and January and May 2008. Few wastewater indicator chemicals were detected in source water; however, low concentrations of some commonly used herbicides were detected in the source and finished water from all three facilities. None of these compounds were detected in finished water at or above established drinking-water standards. Modern society depends upon chemicals to prevent and combat disease, cleanse and soften skin, smell better, reduce wrinkles, influence moods, and control weeds and insects for safety and aesthetic reasons. These compounds, which can be found in any drug or hardware store, enter the environment through runoff from agricultural fields, urban lawns, highway rights of way, parks and recreational areas, domestic sewage, and other sources. Some of these compounds have been shown to be stable in the environment, and also have been shown to survive the conventional drinking-water treatment process and be detected in the finished drinking-water supply. Little is known about the abundance and persistence of these compounds in surface waters of Mississippi; hence, there is little information on what effect further development in basins upstream of source-water intakes will have on downstream communities that rely on surface water as their source for drinking water.
The Use of Microcosm Studies to Determine the Effect of Sediments and Nutrients on Fecal Indicator Bacteria in Lake Water
Year: Authors: Kinnaman A., Surbeck C.Q.
Field and laboratory experiments were conducted to determine the effects of sediments and nutrients on the persistence of the fecal indicator bacteria (FIB) groups total coliforms and <i>Escherichia coli (E. coli)</i> in lake water using samples collected in the field and laboratory-based microcosms. Samples were collected at a discharge point of Thompson Creek into Lower Sardis Lake in northern Mississippi. Samples were tested for total coliforms, <i>E. coli</i>, dissolved oxygen, temperature, dissolved organic carbon, nitrate, phosphate, and phenols. Following initial sample testing, seven microcosms were created in the laboratory: (1) lake water, (2) lake water and sediment, (3) lake water and sterilized sediment, (4) sterilized lake water and sediment, (5) sterilized deionized water and sediment, (6) sterilized lake water (control),and (7) sterilized deionized water and sterilized sediment (control). Each microcosm had a function to test a different hypothesis related to whether sediment affected FIB concentrations in water and vice-versa. Samples from each microcosm were collected approximately every 12 hours for two days and 24 hours for the subsequent five days. FIB concentrations from the microcosms were plotted against time, and first-order decay constants were obtained. In addition, correlations were run between FIB decay constants and water quality parameters to assess the dependence of FIB die-off on nutrients. Preliminary results show that FIB decay rates were lower when sediment was present and that high dissolved organic carbon concentrations were associated with a temporary increase in FIB concentrations. The data found on die-off rates and on FIB dependence on nutrients is useful to determine parameters for numerical modeling in lakes.
Drinking Water Systems in Mississippi: Public Owned or Government Owned?
Year: Authors: Barrett J.
Mississippi (MS) contains approximately 1300 water systems (system). Currently, there has been no issue raised in an effort to make systems more efficient or more economical for the customers. Also, there has been no effort to determine if a system is efficient or economical. The Mississippi State Department of Health (MSDH) completes a capacity development assessment annually for every system and the scores encompass technical, managerial, and financial, ranging in value from 0 (zero/worst) to 5 (five/best). Approximately forty percent of systems with a population below 501 consistently score below 3.0 on the capacity assessment. There are contradictory mindsets in MS as to the future direction of systems: (1) all systems should take whatever actions possible to provide safe drinking water to their customers at an affordable price and (2) this water system has been in my family for generations or this water system holds this community together. I will use the MSDH assessment scores to view the viability of specific systems by population ranges. This will set a basis to current status and possible future action in relation to systems by asking: does the system remain apathetic and ask for assistance once the system is in disrepair, does the state of MS take over, or will water related agencies promote continuing education in an effort for the systems to increase viability themselves. With each of these three options, I will look at the agencies and individuals involved and delineate how they will be affected and why it matters to them. The results should show how economies of scale affect systems in the matter that smaller systems tend not to be as economical or efficient for its customers.
Laboratory-Scale Treatment of CCA-Contaminated Wood Waste
Year: Authors: Bricka R.M., Broussard J.
Since the early 1970’s, the most widely used preservative in the wood preservation industry has been chromated copper arsenate (CCA) treatment. Current estimations suggest that there may be as much as 240 million tons of CCA wood waste available for Disposal by the year 2020. <br /><br /> Until recently, landfilling the out of service materials was a generally accepted method of disposal. Recently, problems with soil and groundwater contamination have arisen, and the role of CCA impregnated wood waste in the matter has been confirmed. As a result, the need for an efficient and effective method of heavy metal separation form wood waste has become eminent. <br /><br /> In this research, electrokinetic treatment of CCA impregnated wood fines was examined. Out of service CCA wood waste was subjected to electrokinetic treatment in a batch reactor under pH controlled conditions. The ionic nature of the metal oxides contained in the CCA impregnated wood will allow for the metals to be mobilized and metal concentrations are expected to decrease in the waste wood while increasing the proximity of the electrodes. In addition to this base case study, chemical extractions with electrode amendments were examined under controlled conditions before they were subjected to electrokinetic treatment, and final overall metal removal. Mass balances were performed using ICP-AES equipment. In the extended research plan, the more effective reactions sequences will be subjected to further testing where the roles of independent variables such as reactor solution pH, particle size, current density, Oxidation/Reduction potential, and treatment time will be examined. The ultimate goal of this research will be to evaluate the feasibly of Electrokinetic pretreatment for CCA impregnated wood.
Oceanic-Atmospheric Modes of Variability and Their Effects on River Flow in the North Central Gulf of Mexico
Year: Authors: Sanchez-Rubio G., Perry H.M., Biesio P.M.
The present study examined the individual and combined influences of four oceanic-atmospheric modes of variability on Mississippi River and Pascagoula River flows. Mississippi River and Pascagoula River mean flows, within long-term climatic phases, were compared using a parametric t-test. While the combination of Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and North Atlantic Oscillation (NAO) phases determined long-term Mississippi River regimes, the coupling of AMO and NAO phases determined long-lasting Pascagoula River flow regimes. Mississippi River mean flow was higher during the PDO warm (PDOw), AMO cold (AMOc), and NAO positive (NAOp) phases than during the PDO cold (PDOc), AMO warm (AMOw), and NAO negative (NAOn) phases. Pascagoula River mean flow was higher during AMOc and NAOp phases than during AMOw and NAOn phases. During a long-term drought regime in the Pascagoula River basin, interannual fluctuations in the Pascagoula River flow were associated with the El Niñ o Southern Oscillation (ENSO) events. During the AMOw/NAOn phase, Pascagoula River flow showed a significantly steady reduction from ENSO warm to ENSO neutral to ENSO cold events. In the northcentral Gulf of Mexico, more than 90% of the freshwater is discharged by the highly correlated Mississippi, Atchafalaya, Pascagoula, and Pearl Rivers. Climate-related hydrological regimes have been associated with fisheries resources availability and the economic and social wealth of coastal communities.
Modeling Fluid Mud
Year: Authors: Hall C.L.
Fluid mud is defined as a high concentration aqueous suspension of fine-grained sediment in which settling is substantially hindered. Fluid mud occurs in many ports and channels around the world. It can severely affect navigation due to the sharp increase in sediment concentration returning a false bottom to sonar systems, and the fluid mud can fill in channels faster than it can be dredged, restricting port access. Fluid mud can also suffocate benthic organisms or contribute to eutrophication. This study is designed to further advance the field of fluid mud modeling to aid in the prediction of fluid mud formation and movement. Most available hydrodynamic models do not include a fluid mud routine. The addition of fluid mud equations to these existing models could greatly enhance sediment process modeling in areas that experience fluid mud. These equations calculate formation, dissipation, flow, and consolidation to adequately describe the physical processes affecting fluid mud. Modeling results using these equations compared with field data as well as laboratory experiments will determine their usefulness. Laboratory experiments include measuring the flow of fluid mud under shear stress and on a slope. With accurate prediction of the physical processes governing fluid mud, dredging alternatives could be developed to reduce dredging requirements and improve port access.
Occurrence of Nitrate in the Mississippi River Valley Alluvial Aquifer at a Site in Bolivar County, Mississippi
Year: Authors: Welch H.L., Coupe R.H., Green C.T.
Annually in the United States, about 12 million tons of nitrogen are applied as commercial fertilizer causing contamination of surface and groundwater resources. In the Mississippi Delta, large amounts of agricultural chemicals are applied to crops on an annual basis, but are rarely detected in groundwater. Previous studies have indicated that the shallow alluvial aquifer in the Delta is unaffected by anthropogenic activities at the surface because of an overlying impervious clay layer. However, model simulations have indicated that the alluvial aquifer is recharged by a small percentage (5%) of rainfall. In 2005, the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program began a study in the Bogue Phalia basin to assess how environmental factors and agricultural practices affect the source and transport of agricultural chemicals. Two wells located in a cotton field (surveyed as very fine sandy loam and silty clay) in Bolivar County, Mississippi were sampled for inorganic compounds, nutrients, and field parameters from June 2006 to November 2008. Nitrate was detected at concentrations ranging from 7.2 to 13 mg/L in a shallow well screened near the water table from 27 to 32 feet, but was not detected in a deeper well screened from 70 to 120 feet located approximately one-quarter mile from the shallow well. In June 2008, depth interval sampling was conducted in test holes drilled adjacent to the shallow well to better define the occurrence of nitrate at five depths ranging from 32.5 to 60 feet–between the depths of the shallow and deep wells. Nitrate concentrations decreased with depth in the water column, and there were no detections below a depth of 36 feet. Data indicate that some nitrate is being transported through the unsaturated zone into the alluvial aquifer, but it is being converted fairly quickly into ammonia and nitrogen gas under strong, reducing conditions in the aquifer. The data imply that the aquifer may not be as invulnerable to anthropogenic activities as previously thought.
Exploring Biologically Relevant Buffer Zones for Aquatic and Wetland Ecosystems in Northern Mississippi
Year: Authors: Ervin G.N.
Intact natural buffers surrounding streams and wetlands can reduce nutrient runoff into the water column, reduce sedimentation, and maintain or enhance general habitat quality for wildlife. However, a major obstacle in efforts at water quality improvement relates to the appropriate definition of what constitutes a sufficient buffer, in terms of buffer width or type of land cover within the buffer. The present studies evaluated patterns of correlation between land cover and wetland vegetation or aquatic biota to investigate optimal buffer widths associated with ecological integrity of inland freshwater streams and wetlands in northern Mississippi. Results indicated that the presence of a forested buffer (i.e., natural forest, silvicultural plantings, or a combination) of 70 to 100m in width was associated with an increase in ecological quality. Here, quality was represented as either the presence of species of high ecological conservation value, presence of plant species adapted to wetland conditions, or the absence of non-native plant species. On the other hand, landscape-scale disturbances were correlated with decreased ecological quality. For example, at proximities of 50m and beyond, there was a consistent association of agricultural land cover with the presence of non-native plant species in northern Mississippi wetlands. The conclusion is that intact, undisturbed buffers help to minimize negative impacts of land use on wetland and aquatic assemblages in the study area, but biological evidence of human activities remains, even where buffers are present.
Flooding or Precipitation: What is the Dominant Source of Moisture Sustaining a Backwater Bottomland Hardwood Forest?
Year: Authors: Johnson D.R.
When modeling the potential impact of the Yazoo Backwater Pump Project on the Bottomland Hardwood Wetlands, the Corps assumed the precipitation played an insignificant role in the sustenance of these wetlands. That assumption will be examined through the use of a water budget equation and groundwater monitoring wells. <br /><br /> The dominant water demand in forested areas is from evapotranspiration. It is generally presented that a forested area will be a wetland if precipitation exceeds evapotranspiration. A wetland water budget is actually much more complicated than that. Forested wetlands have four potential sources of moisture: precipitation, surface water, groundwater, and tidal, and four potential methods to lose water: evapotranspiration, surface runoff, infiltration into groundwater and tidal. Yazoo Basin wetlands are not affected by tides and are disconnected from the alluvial aquifer by a confining clay layer. Thus there are only two remaining sources of moisture: precipitation and surface water (riverine flooding). This presentation will compare the relative roles of these two sources of moisture to the forested wetlands in the Yazoo Backwater Area.
National Weather Service flood inundation mapping
Year: Authors: Graschel J., Reed D.B.
The National Weather Service (NWS) is responsible for issuing river and flood forecasts and warnings to mitigate the loss of life and property. Current NWS text-based products are utilized by emergency managers (EMs). One of the most often requested product from EMs is flood inundation mapping to show the areal extent of flooding. Flood inundation maps would translate the forecasted stages into inundation areas, making it easier for EMs to take action and alert the public. They would also prove invaluable to EMs in their outreach, mitigation, and educational efforts. By partnering with the Federal Emergency Management Agency (FEMA) and local communities, the NWS is developing flood inundation maps for their forecast locations. When a community performs flood studies to update FEMA Flood Insurance Rate Maps (FIRMs), much of the necessary data are available to develop flood inundation maps. For a small incremental cost above the cost to develop FIRMs, flood inundation maps at various stages above the NWS-established flood stage are being developed. This collection of maps will form a flood inundation map library that can be served up to the public via the Internet. The NWS has partnered with FEMA and developed flood inundation map libraries at about 15 locations across the country. Currently, work is ongoing to produce these maps for an additional 30 sites in the states that border the Gulf of Mexico. The NWS has established a web site and web structure to serve this data up to the public.
National Weather Service flood inundation mapping
Year: Authors: Graschel J.
The National Weather Service (NWS) is responsible for issuing river and flood forecasts and warnings to mitigate the loss of life and property. Current NWS text-based products are utilized by emergency managers (EMs). One of the most often requested product from EMs is flood inundation mapping to show the areal extent of flooding. Flood inundation maps would translate the forecasted stages into inundation areas, making it easier for EMs to take action and alert the public. They would also prove invaluable to EMs in their outreach, mitigation, and educational efforts. By partnering with the Federal Emergency Management Agency (FEMA) and local communities, the NWS is developing flood inundation maps for their forecast locations. When a community performs flood studies to update FEMA Flood Insurance Rate Maps (FIRMs), much of the necessary data are available to develop flood inundation maps. For a small incremental cost above the cost to develop FIRMs, flood inundation maps at various stages above the NWS-established flood stage are being developed. This collection of maps will form a flood inundation map library that can be served up to the public via the Internet. The NWS has partnered with FEMA and developed flood inundation map libraries at about 15 locations across the country. Currently, work is ongoing to produce these maps for an additional 30 sites in the states that border the Gulf of Mexico. The NWS has established a website and web structure to serve this data up to the public.
Interactions between ground water and surface water in the Bogue Phalia near Leland, Mississippi, Summer 2007.
Year: Authors: Gebhard C., Stone K.
Ground-water discharge is a key control on streamflow quality and quantity and associated aquatic ecosystems; however, factors that affect the spatial and temporal distribution of water flux across stream beds remain poorly understood. The objective of this study is to characterize ground-water and surface-water interaction in the Bogue Phalia, which drains an agricultural area in northwestern Mississippi. Study sites are located near the Bogue Phalia gaging station near Leland, MS. At the study sites, the Bogue Phalia is about 35 meters wide with a maximum depth at low flow of 1.2 meters and a discharge of 78 cubic feet per second during the study period (June–August 2007). Ground-water discharge was measured with pan and bag seepage meters fitted with extensions for deployment in deep (>1 meter) water. Five arrays were measured across the width of the river, with an average of 10 meters between each array and at least 5 meters per array. Seepage data were supplemented with measurements of head gradient, hydraulic conductivity, bed sediment grain size, and temperature in order to better understand interactions between ground water and surface water. Drought conditions in the area were temporarily relieved by storms in late June and early July when flow in the river reached a maximum of 5,120 cubic feet per second. Measurements were made both before the storms and after flow in the river returned to base conditions in order to evaluate the effects of flooding on ground-water discharge. Preliminary results indicate that the highest ground-water discharge fluxes occurred along the central axis of the Bogue Phalia; whereas, the lowest fluxes occurred along the banks. The main channel was gaining at the study sites, although losing reaches were common in ditch-like tributaries. The average and (standard deviation) of vertical flux through the study area was 1.2 x 10-6 meters per second (m/s) (6.3 x 10-7 m/s), and ranged from a minimum of 3 x10-8 m/s to a maximum of 5 x10-6 m/s. Techniques for setting seepage meters in deeper water produced an average coefficient of variation (COV) of 0.5, which is greater than the typical value for shallow water application (COV = 0.3). The mean flux before the storms in late June and early July is statistically indistinguishable from the mean after the storms. Although the maximum flux increased slightly from 4.2 x10-6m/s (2.7 x 10-6 m/s) to 5.6 x10-6m/s (1.8 x 10-6cm/s) and shifted position by approximately 30 m upstream following the storm. The highest fluxes always occurred in areas where the stream bed was composed of medium- to coarse-grained sand, whereas the lowest fluxes occurred where the bed sediment was fine-grained, primarily along the banks and particularly downstream of a tributary. Seepage-meter studies elsewhere in the Southeastern United States have shown average ground water discharge fluxes of approximately an order of magnitude greater than those at the Bogue Phalia, an effect that could be due to either ground-water pumping or drought conditions.
Primary productivity, hydro period, and nutrient cycling in four flood-plain forest communities on a blackwater river
Year: Authors: Burke M.K., Eisenbies M.H., Harrison C.A., Liechty H.O.
A characterization of a blackwater river floodplain forest in South Carolina was conducted to 1) provide a reference for better management and restoration of this forest type, 2) test the subsidy stress hypothesis, 3) relate variations in hydroperiod to primary productivity and nutrient cycling among years and communities, 4) identify ecological processes potentially responsible for differences in productivity among communities and years, 5) identify mechanisms that contribute to water quality improvement by these forests, and 6) identify potential limiting nutrients on the site. The forest communities exhibited the classic subsidy stress curves of productivity along a flooding gradient over a period which included a wide range of moisture conditions. Greatest productivity occurred on the community occupying middle elevations. Also in that community, amplitude in productivity increased when flooding returned after several dry years, and this was attributed to luxury consumption of P during dry years and a fertilization e effect by N subsidies arriving with subsequent floods. Several mechanisms of N sequestration were identified, including uptake by trees with induced N deficiencies through luxury P uptake, and there was evidence of a N limitation of productivity in this nutrient rich and productive floodplain forest. Because eutrophication of marine systems is related to N runoff from terrestrial sources, these forests may be important to sustainable water quality on the coast.
Sensitivity analysis of simultaneous nitrification-denitrification process by simulation with activated sludge model number one
Year: Authors: Dey A., Magbanua B.S.
Nitrogen removal by Simultaneous Nitrification-Denitrification (SND) has invited much attention in recent years due to possible reduction in capital and operating costs associated with wastewater treatment. The potential of biological nitrogen removal through this process and optimization of its operating parameters were investigated by simulations using Activated Sludge Model No. 1 (ASM1). Adopting typical properties of domestic sewage, simulations of SND process were performed in three sequential phases to optimize the operating parameters and assess reliability of the SND process over variation in the kinetic and stoichiometric parameters. Since dissolved oxygen (DO) concentration and solids retention time (SRT) were considered to have the most significant impact on nitrogen removal, the first set of simulations was aimed at identifying an applicable operating window for these parameters. Simulation results indicated that optimum nitrogen removal occurred at a DO concentration of 0.3 mg/L coupled with a SRT of 15 days. A second set of process simulations was run using this combination of operating DO and SRT to examine the effect of other process parameters; specifically the ratio of biodegradable COD to total Kjeldahl nitrogen (BCOD:TKN) in the influent, hydraulic residence time (HRT), and recycle ratio (R) on total nitrogen removal. The influent BCOD:TKN ratio significantly affected overall nitrogen removal, since availability of electron donor is essential to drive denitrification, with optimal nitrogen removal observed at a BCOD:TKN ratio of 11. Neither HRT nor R had a significant effect on nitrogen removal. The third set of simulations considered the natural variability of the kinetic and stoichiometric parameters of ASM1. Monte Carlo analysis was performed to evaluate the performance of an SND system operated at a DO of 0.3 mg/l and an SRT of 15 d using probability density functions developed by Cox (2004) for the model parameters. Results of these simulations were used to assess the potential reliability of an SND process designed using "typical" model parameter values. A sensitivity analysis was also performed to identify the model parameters that had most significant effect of nitrogen removal.
Small farm plots and application of simulated rain to determine the potential for baterial runoff after poultry litter surface application to bermudag
Year: Authors: Brooks J., Adeli A.
Land application of poultry litter is an economical and environmentally viable use of this manure by-product. However the recent concern associated with fresh produce and pathogenic bacterial contamination has led to increased scrutiny regarding land applied manures. Runoff following a rain event is one possible source of environmental contamination resulting from manure application. In this second part of a two-part study a series of treatments involving litter (two rates), inorganic fertilizer, and no fertilizer controls were added to bermudagrass plots held on the Mississippi State south farm to simulate "real-world" conditions and extend the baseline data gathered during the greenhouse trials previously conducted. A rainfall simulator was used to simulate precipitation events and following each rain event, runoff samples were collected for microbial analyses. Total Heterotrophic Plate Count (HPC) bacteria, antibiotic resistant bacteria (ARB), thermal-tolerant coliforms, enterococci, staphylococci, and Clostridium perfringens were investigated. Over a period of 60 days, 5 rain events were simulated using a portable rain applicator and results indicated that staphylococci, enterococci, and clostridia correlated well with manure application, corroborating the previous greenhouse study. Analysis of runoff concentration means demonstrated that in most cases litter application increased the presence of indicator microorganisms in runoff water. Traditional indicators such as thermal-tolerant and total coliforms performed poorly as fecal indicators relative to the other bacteria assayed in this study. No "frank" pathogens such as Salmonella or Campylobacter were detected in the applied litter or runoff. Chi square analysis of ARB indicated that litter application influenced the overall presence of antibiotic resistant bacteria, particularly with respect to polymixin B and aminoglycoside resistance. This study indicated that poultry litter land application can contribute to microbial runoff, however proper land and agronomic management practices can mitigate this.
Long-term performance of a pump and treat system at a wood treating site
Year: Authors: Borazjani H., Diehl S., Hannigan M., Prewitt M.L.
A wood treating facility in South Mississippi was the site of a twelve year, pump and treat remediation. Two sixty-five thousand liter batch reactors treated approximately 250,000 liters of creosote and penta contaminated groundwater per day. Four liters of penta and creosote degrading bacterial culture and 5 kg of triple thirteen fertilizer were added to the reactors on a weekly basis. The approximate residence time in reactors was 12 hours. Samples were taken on bi-weekly basis for Total Suspended Solids (TSS), selected priority pollutant creosote constituents/polycyclic aromatic hydrocarbons(PAHs), Penta and Tetrachlorohenol (PCP&TCP), Biological Oxygen Demand (BOD), and microbial counts. Reduction of PAHs, PCP/TCP, BOD, and TSS were 97%, 44%, 61%, and 54% respectively; viable bacterial populations over (700,000 colonies/mL) were present in effluent samples during a twelve year period.
Improving the capacity of Mississippi’s rural water associations through board management training
Year: Authors: Barrett J., Barefield A.
The Mississippi legislature enacted legislation designed to increase the capacity of Mississippi’s rural water associations’ boards and small municipal water systems’ government officials to provide safe drinking water and be aware of the technical and legal responsibilities assumed by these individuals. This legislation mandated that the Mississippi State Department of Health (MSDH), in cooperation with other organizations such as the Mississippi Rural Water Association (MWRA), provide training to the governing bodies of these systems. To this end, the MSDH contracted with the Mississippi State University Extension Service (MSUES) to develop training curricula and provide coordination and evaluative services to facilitate the provision of quality training opportunities accessible to clientele across the state. Furthermore, partnerships between MSUES, MWRA, the Mississippi Water and Pollution Control Operators Association, and the Community Resource Group, has resulted in the development of several cutting edge curricula that have been nationally recognized.
Influences of light intensity variations on growth characteristics of parrotfeather (Myriophyllum acquaticum (Vell.) Verdc.)
Year: Authors: Wersal R.M., Madsen J.D.
Parrotfeather (Myriophyllum aquaticum (Vell.) Verdc) is a nonnative aquatic heterophyllous plant. Having both a submersed and emergent growth form may allow M. aquaticum to invade and colonize highly disturbed or less than optimal environments through changes in growth habit. The reallocation of resources to emergent or submersed growth likely allows M. aquaticum to overcome changes in light availability. Currently, little is known regarding the ecological and biological responses of M. aquaticum to perturbations in environmental factors. The objective of this study was to quantify M. aquaticum growth under different shading regimes. We hypothesized that M. aquaticum growth would increase as shading levels increased to a maximum of 70% of full sun light. The study was conducted using potted M. aquaticum plants growing in 24, 1100-liter tanks. Light treatments consisted of full sun, 30% shade, 50% shade, and 70% shade achieved using shade cloth with each treatment replicated six times. Biomass was harvested in two-week intervals for 12 weeks. Two pots from each tank were collected and both the roots and shoots of M. aquaticum were harvested. Measurements were taken of total plant length, emergent shoot length, submersed shoot length, and the total of number of emergent and submersed shoots were recorded. Plants were sorted to emergent shoots, submersed shoots, roots, stolons, and dried at 70 °C to a constant mass then weighed. Myriophyllum aquaticum biomass was significantly different (F = 18.1, d.f. = 47, p < 0.01) at the conclusion of 12 weeks between shade treatments. Differences in biomass were a result of greater emergent shoot growth in the 50% shade treatment and a reduction in the 70% shade treatment. Total plant length was also significantly different (F = 7.44, d.f. = 95, p = 0.02). The greatest plant length was observed in the 50% shade treatment with reductions in overall plant length observed in full sunlight. Both emergent and submersed shoot lengths were greatest in the 70% shade treatments. The total number of emergent and submersed shoots was not different between shade treatments. Our data suggests that intermediate light availability may be optimal for M. aquaticum growth.
Water supply calculation of Stonegate Arch
Year: Authors: Xiong Y., Burns T.B.
Stonegate Arch water supply system is modeled and calculated using EPANET 2 and AutoCAD based on related regulations, site survey data and waterline layout. In the hydraulic modeling, a reservoir is employed to provide the pressure for the whole on site water supply system. To simplify the modeling, the typical water supply points are assumed to be located at the midpoints of the corresponding pipe segments. One on site outdoor fire hydrant is open to check the whole water supply system so as to maintain an acceptable pressure in the distribution system. Minor loss coefficient for each pipe segment is identified and incorporated in the calculations. Five scenarios of the water supply system are calculated to show the pressure & velocity variations at the control points in Stonegate Arch water supply piping system. The results represent that fire flow has significant impact on the velocity & pressure in the scenarios with fire flow. In addition, water demand and the location of concern determine the value of velocity & pressure variations. For the scenarios without fire flow, domestic water demand and pipe size determine the value of pressure & velocity variation.
Decision support tools for implementing and managing regional utilities in Mississippi
Year: Authors: Bryson J.R., Brown G.A.
The regionalization of utilities can increase the efficiency and quality of any system. However, both the implementation and subsequent management of regional utilities involve a substantial effort for any municipality or government agency. The agglomeration of several smaller utilities requires careful planning and consistent management and maintenance. In the case of water and wastewater utilities, many of these systems are aging and the location and condition of infrastructure is unknown. Regionalization allows these systems to maximize their resources and streamline their day-to-day activities. One of the dominant tools aiding in the regionalization of utilities is Geographic Information Systems (GIS), which enables utility providers to link location with infrastructure. The use of GIS can greatly simplify the management of existing utilities and also strengthen the design of new utilities. The development of a GIS allows utility providers to quickly locate infrastructure and track repair and maintenance history. They can also use the information stored in the GIS to model future demand/capacity and plan for future infrastructure needs.
Potential for recharge in agricultural soils of the Mississippi Delta
Year: Authors: Perkins K.S., Nimmo J.R., Coupe R.H., Rose C.E., Manning M.A.
Ground water models predict that 5 percent or less of precipitation in the Mississippi Delta region recharges the heavily-used alluvial aquifer; however high concentrations of agricultural chemicals in ground water suggest more substantial recharge. In a preliminary assessment of the potential for aerial recharge through the agricultural soils of the Bogue Phalia basin in the Mississippi Delta, we applied a method for rapidly measuring field-saturated hydraulic conductivity (Kfs) in 26 locations in cotton and soybean fields. The technique makes use of a portable falling-head, small-diameter, single-ring infiltrometer and an analytical formula for Kfs that compensates both for falling head and for subsurface radial spreading. Soil samples were also collected at the surface and at about 6 cm depth at each location for particle size analysis. Kfs values are generally higher than anticipated and vary over more than three orders of magnitude from 1x10-2 to 5x10-6 cm/s. There is also a correlation between Kfs and mean particle size which may prove useful in generalizing recharge rates over larger areas. A 2-m ring infiltration test is planned that will include the use of tracers and subsurface instruments for measuring water content and matric potential from the near surface to about 5 m to evaluate flow and transport below the root zone.
Aerobic-anaerobic lagoon evaluation in a small rural community in Columbia, South America
Year: Authors: Salazar-Mejia G., Ramirez J.A., Cadavid L.S., Diaz-Ramirez J.N.
Environmental State agencies have been supporting the construction of Wastewater Treatment Plants (WTPs) in Colombia, South America. There is not much technical evaluation of the performance of these WTPs. The objective of this research was to evaluate the performance of an aerobic-anaerobic lagoon located in the rural area of Palmira City, Valle del Cauca. The lagoon was constructed around 1984 and was originally designed for 240 people. However, uncontrolled habitat growth in the study area has resulted in the treatment plant receiving wastewater from approximately 500 people. Water quality data were collected between September and November, 2006 on the influent and effluent of the system. In-situ water quality measurements (temperature, pH, and dissolved oxygen) were observed every hour for 24 hours during five different days. Composite samples of every day were analyzed in the laboratory for chemical oxygen demand, five-day biochemical oxygen demand, coliforms, solids, conductivity, acid, oil and grease, nitrogen, and phosphorus. The lagoon reached the efficiency values according to standards declared by the 1984 Colombian National Government Law of Permit Limits. There was no preliminary treatment of the wastewater prior to reaching the lagoon; therefore, the system was trapping a lot of sediments and the actual effective volume of the WTP decreased approximately 65% from its original design. The lagoon was mainly working under anaerobic conditions because observed dissolved oxygen values were very low. The effluent of the lagoon can be used for crop irrigation or be discharged into a water body.
Duckweed control in Mississippi waters
Year: Authors: Cheshier J.C., Wersal R.M., Madsen J.D.
Duckweed (Lemna minor L.) is a free floating plant that is native to the southeastern United States. However, duckweed has an invasive growth habit and can overtake stagnant waters in both lakes and rivers. Two studies, a field demonstration and a replicated tank study, were done in Mississippi during 2007. The field demonstration was conducted in a 4.4 hectare lake near Holcomb, MS that was completely covered with duckweed. Fluridone was used in a sequential treatment of 50 parts per billion (ppb) on May 28th followed by 40 ppb treatment one month later. Duckweed biomass was reduced by greater than 90% following the second treatment (p < 0.01). The second study was conducted in outdoor 40 L tanks at the R.R. Foil Plant Science Research Station, Mississippi State University. Duckweed was treated with diquat at 0.37 parts per million (ppm) injected into the water, diquat at 0.37 ppm with a methylated seed oil (MSO) at 1% v/v injected into the water, diquat at 2 gallons per surface acre with 1% MSO applied to the surface, and 1% MSO alone. Biomass was significantly reduced 3 days after treatment (p < 0.01) with all treatments. We have demonstrated several different tools that may be used to control nuisance growths of duckweed in Mississippi waters.
Littoral zone aquatic plant community assessment of the Ross Barnett Reservoir, Mississippi for 2007
Year: Authors: Madsen J.D., Wersal R.M., Tagert M.L.
As the threat of non-native plant species increases, the development and refining of methods to rapidly detect, monitor and ultimately control these species to mitigate negative impacts is critical. Three non-native aquatic plant species that have caused major problems throughout the United States are waterhyacinth (Eichhornia crassipes) alligatorweed (Alternanthera philoxeroides), and hydrilla (Hydrilla verticillata), and all three species. In Mississippi, these species can be found in the Ross Barnett Reservoir. Waterhyacinth and alligatorweed have been under intensive management for almost a decade, primarily through the use of contact herbicides. Hydrilla was first observed in the Reservoir in 2005 and has since undergone aggressive management through the use of the systemic herbicide fluridone. To ensure that these management techniques are successful and to assess impacts to the native plant community, we conducted a survey of the littoral zone to monitor and record changes in the occurrence of plant species. The survey of the Ross Barnett Reservoir yielded 19 species of aquatic and riparian plants. The dominant species was the native plant American lotus with a percent frequency of occurrence of 21.1%. The occurrence of each non-native species was below 5% with alligatorweed observed most often (4%). Hydrilla had a frequency of occurrence of 1.4%. The frequency of occurrence for both waterhyacinth and alligatorweed decreased significantly (p = 0.01) from 2005 to 2007. The frequency of occurrence for waterhyacinth in 2005 was 4.9% and declined to 2.9% and 1.2% in 2006 and 2007, respectively. The occurrence of alligatorweed was reduced from 21.1% in 2005 to 4.0% in 2007, approximately an 80% reduction. Furthermore, the removal of waterhyacinth and alligatorweed from some areas of the Reservoir has not impacted the overall species richness (mean number species per point) over the past three years. The occurrence of species (American lotus, white waterlily, American pondweed, and coontail) growing in association with both alligatorweed and waterhyacinth did not significantly change between years, indicating that waterhyacinth and alligatorweed are being selectively removed with little impact on native plant species or species richness. Additionally, hydrilla has been effectively removed from 5 areas of the reservoir totaling more than 161 acres.
Reservoir survey for invasive and native aquatic plants species within the Pat Harrison Waterways District
Year: Authors: Robles W., Maddox V., Madsen J.D.
The Pat Harrison Waterway is composed of nine water parks for recreational use (e. g. boating and fishing) located south Mississippi along the Pascagoula River Basin. Invasive aquatic plant species has been reported in some of these water bodies. Because recent information is lacking on the occurrence of native and invasive aquatic plant species in these systems, we were asked to perform surveys on six of the reservoirs in the system. Species occurrence information is important as a baseline to select and implement management methods on this water bodies. Aquatic vegetation surveys were conducted during the year 2007 over six Pat Harrison’s water bodies using point-intercept method. This survey method consists in navigating to point locations covering the entire lake assisted by global positioning system (GPS). For all six water bodies, many native plant species were found and only four exotic plant species: Myriophyllum aquaticum, Najas minor, Alternanthera philoxeroides, and Panicum repens. The submersed N. minor was commonly found composing benthic aquatic vegetation. Emergent species A. philoxeroides, P. repens, and M. aquaticum, were found along shorelines and boat ramps. Chemical control using spot treatments of herbicides along with a monitoring program were recommended. The implementation of a monitoring program is the least expensive management approach to these nuisance plants because rapid response to the first detection of a new species’ occurrence may prevent its further spread.
The phytoplnakton monitoring network
Year: Authors: Sallis A.
The Phytoplankton Monitoring Network (PMN) is a volunteer regional data management network to assist the Harmful Algal Bloom Observing System (HABSOS) effort. PMN is an education and outreach program developed by NOAA’s National Ocean Service to engage school and community volunteer groups in phytoplankton sampling and identification and to raise awareness of harmful algal blooms. The National Coastal Data Development Center (NCDDC) partnered with PMN to create an end-to-end data management system for the volunteers. Members are provided an on-line data entry tool to submit data, and are then able to visualize and analyze their own validated data as well as from Network peers in an Internet Geographic Information System (GIS) environment. Approved data is mapped to (www.ncddc.noaa.gov/website/SEPMN/viewer.htm). NCDDC has partnered with the newest NOAA Cooperative Research Institute, the Northern Gulf Institute (Mississippi State University, University of Southern Mississippi, Louisiana State University, Florida State University, and Dauphin Island Sea Lab) to train and equip the volunteer organizations.
Big Sunflower River water quality assessments following streamflow augmentation
Year: Authors: Tietjen T., Ervin G.
The Big Sunflower River is listed on the EPA Section 303(d) list of Impaired Waterbodies of Mississippi. Contributing to the decline in conditions in this system are the substantial decreases in baseflow during the late summer and fall as groundwater levels decline. In an attempt to improve water quality and ecological conditions the Yazoo Mississippi Delta Joint Water Management District has begun supplementing flows during critical periods using groundwater for the past 2 years. To assess the impact of streamflow augmentation we evaluated water quality trends through the 2006-2008 pumping periods and assessments of the quality of the riparian plant community during the summers of 2006 and 2007. Measurements of water quality (Temperature, Dissolved Oxygen, pH, Specific Conductance and Turbidity) were made at 11 locations on the Sunflower River between Indianola and North Clarksdale, at one location associated with the augmentation pumps and 1 location along the channel used to funnel pumped water to the Sunflower River. In general, water quality continued to be better above Clarksdale, with improvements in dissolved oxygen concentrations associated with increased flows and decreased temperatures. The riparian plant community was analyzed over a more focused portion of the upstream drainage basin with 2 sites south of Clarksdale, 2 sites north of Clarksdale and 1 within the city itself. Clarksdale represented a clear break in plant composition with higher numbers of moncots, invasive species and weedy early succession species encountered upstream (North) of Clarksdale. Taken together, there is a strong indication that supplementing natural stream discharge can have beneficial impacts on water quality in the near term and on broader measures of ecosystem quality in the long term.
1:24,000-scale watershed boundary dataset for Mississippi
Year: Authors: Wilson Jr. K.V., Clair III M.G.
The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, U.S. Department of Agriculture Natural Resources Conservation Service, Mississippi Department of Transportation, U.S. Department of Agriculture Forest Service, and the Mississippi Automated Resource Information System developed a 1:24,000-scale Watershed Boundary Dataset for Mississippi including watershed and subwatershed boundaries, codes, names, and areas. The Watershed Boundary Dataset for Mississippi provides a standard geographical framework for water-resources and selected land-resources planning. The original 8-digit subbasins (Hydrologic Unit Codes) were further subdivided into 10-digit watersheds and 12-digit subwatersheds-the exceptions being the Delta part of Mississippi and the Mississippi River inside levees, which were subdivided into 10-digit watersheds only. Also, large water bodies in the Mississippi Sound along the coast were not delineated as small as a typical 12-digit subwatershed. All of the data-including watershed and subwatershed boundaries, subdivision codes and names, and drainage-area data-are stored in a Geographic Information System database.
Climatological and cultural influences on annual groundwater decline in the Mississippi Delta shallow alluvial aquifer
Year: Authors: Wax C.L., Pote J.W., Merrell T.L.
The shallow alluvial aquifer in the Mississippi Delta region is heavily used for irrigation of corn, soybeans, and cotton, as well as for rice flooding and filling aquaculture ponds in the prominent catfish industry. Water volume in the aquifer is subject to seasonal declines and annual fluctuations caused by both climatological and crop water use variations from year-to-year. The most recently documented water volume decline in the aquifer is estimated at 500,000 acre-feet. This may represent a worst-case situation in which severe drought combined with consequent increased demand for irrigation. Additionally, the region was impacted by historic drought again during the growing season of 2007, and impacts to the aquifer have not yet been quantified. Available climate, crop acreage, irrigation water use, and groundwater decline data from Sunflower County was used to represent the climate-groundwater interactions in the Mississippi Delta region. This research resulted in a model that simulates the effects of climatic variability, crop acreage changes, and specific irrigation methods on consequent variations in the water volume in the aquifer. Climatic variability was accounted for by predictive equations that related annual measured plant water use (irrigation) to growing season precipitation amounts. This derived relationship allowed the application of a long-term climatological record (45 years) to simulate the cumulative impact of climate on groundwater use for irrigation. Results indicate that under the present use scenario, groundwater will remain stable in wet to normal precipitation years, but will decline during drought periods and not recover fully. Use of the model to simulate changes in irrigation methods and crop acreages from 2008 through 2053 shows potential to stabilize the water volume in the aquifer through implementation of various management strategies. The model appears to be a tool that can be used to assess the impact of climatic variability and changes in the cultural practices on groundwater use in the region-a tool that will be useful in making management decisions that will allow sustainable use of the groundwater resource.
The bi-national HABSOS
Year: Authors: Ambrose B.
The Harmful Algal Blooms Observing System (HABSOS) is a regional coalition of U.S. and Mexican Federal and State agencies working together to study algal bloom events within the Gulf of Mexico Ecosystem. Algal toxins introduced into the ecosystem affect the health of humans and marine life, and disrupt social and economic activities. The coastal zone manager is challenged to monitor, assess, and forecast bloom events to minimize societal impact. A bilingual (Spanish/English) HABSOS web site an Internet tools have been developed to support this effort. Data entered into the system are available for display and analysis in the HABSOS Internet Map Service (www.ncddc.noaa.gov/interactivemaps/harmful-algal-blooms-observing-system-habsos). The HABSOS and Bi-National were developed and supported by U.S. Environmental Protection Agency (EPA) Office of Research and Development, EPA Gulf of Mexico Program, and the NOAA National Coastal Data Development Center (NCDDC).
Assessing water quality and phytoplankton in streams of the leaf river and black creek watersheds.
Year: Authors: Anzola N.R., Pessoney G.F., Hernandez C.L.
Physicochemical and phytoplankton data has been collected since 1998 at 26 permanent monitoring stations located in streams draining into the Leaf River and Black Creek in South Mississippi. These streams are fast flowing and originate within the boundary of the Camp Shelby Training Site. Bacteria, nutrients, and physical characteristics are measured quarterly. The measurements are designed to detect acute changes in water quality. A small discharge of pollutants can result in major stream impairment within the boundaries. The danger for contamination of these small streams is that a small point source could cause a large influence in the water quality downstream because there is little water for dilution. This paper summarizes the results of water quality in the period of 2002-2007. Influences outside of the camp area were more pronounced than the military uses within the boundaries. The study shows that there has not been environmental deterioration caused by the land uses at Camp Shelby. The phytoplankton was dominated by diatoms in numeric abundance. However, the Chlorophyta, although widespread in occurrence, included the largest number of genera. Other algae divisions were minor component of the plankton community. Water temperature, flow, and phosphate availability were statistically important factors affecting and controlling phytoplankton abundance and algal richness over time.
Upper Leaf River basin base flow study: A preliminary study for surface water/groundwater interactions within the Pascagoula Basin
Year: Authors: Rawlings L.
The Pascagoula River System, draining 8,504 mi2 in southern Mississippi, is the nation’s largest, unregulated and pristine river system. Streams in the Pascagoula Basin are generally the first to be affected during times of drought. With the presence of several industries in this basin that use surface water, staff of MDEQ/OLWR are conducting studies within the basin to determine the sources of baseflow for the basin’s streams. During October 2007, 25 sites near 7Q10 were individually measured during a baseflow study conducted in the Upper Leaf River Basin utilizing SonTek Flowtracker Acoustical Doppler Velocity meters. The Upper Leaf drains 1,752 mi2 and has been in drought conditions throughout the year. The baseflow sites’ discharge ranged from no-flow observations to a basin high of 375 ft3/s discharging into the Lower Leaf River Basin. Utilizing ArcGIS, the basin’s topography, geology and hydrology was mapped and analyzed. Results indicated that geology plays a pivotal role in the distribution of ground water flow into the surface water streams based on unit discharges per square mile. Generally, flows in the northern third of the Upper Leaf were non-existent correlating to geology. In the southern third, ground water discharge is more prevalent also correlating to the basin’s geology. This study will form the foundation for further studies in the basin for ground water/surface interactions utilizing the mappable Miocene aquifer units and stream incision to locate significant ground water contributions. These methodologies can then be applied to the entirety of Pascagoula River Basin.
An overview of the geology and hydrology of a proposed impoundment of the Upper Sand Creek, Choctaw County, Mississippi
Year: Authors: McMillin J.R., Schmitz D.W., May J.H.
The Upper Noxubee watershed, Choctaw County, Mississippi, constitutes a proposed site for a recreational and water management reservoir located on Sand Creek. Prior to the development of the site, the geology and hydrogeology of the watershed was investigated to determine suitability for impoundment. The proposed site is located within the Wilcox Group, a sequence of interbedded sands, silts, clays and lignites of Paleocene age. Geological cross sections derived from geophysical logs and field exploration provided information regarding facies distributions within the proposed site area. Discharge characteristics of both perennial and ephemeral streams offered data concerning surface runoff that can then be related to infiltration into the Lower Wilcox Aquifer. Along with a spring inventory, the discharge measurements aided in determining if there is sufficient water flow for impoundment. The Mississippi State University Chemical Laboratory conducted water analysis to establish the quality of the water to be impounded. All data collected and the characteristics of the proposed reservoir are mapped using ArcGIS 9.2 software.
Effects of landscape factors on limnological conditions of floodplain lakes in the Yazoo River Basin
Year: Authors: Miyazono S., Aycock N., Miranda L.E., Tietjen T.
The Yazoo River Basin of Mississippi includes several rivers that drain an area heavily impacted by agriculture that includes hundreds of floodplain lakes created by the meandering of these rivers. We studied 17 of these lakes distributed over the lower half of the Yazoo River Basin to document their water quality. Landscape factors were quantified with GIS and used to explore the relationships between water quality and the environment surrounding the lakes. Results of principal components analysis showed that the degree of connectivity and the presence of forested wetland buffers are major factors dividing the physicochemical characteristics of the lakes. Lakes with direct connections to the parent river and limited forested wetland buffers tend to be deeper, less turbid, and have lower phytoplankton fluorescence. Conversely, as connectivity to the parent river is reduced or eliminated and the presence of forested wetland buffers increase, lakes become shallow, turbid, and have higher phytoplankton fluorescence. We postulate that after lakes separate from their parent river they function as sinks for sediments introduced during flood events, resulting in loss of depth. As lakes become progressively shallower, area is reduced, and surrounding wetlands are increased. The effects of changes in connectivity of alluvial lakes need to be included in decisions concerning restoration efforts. Management goals associated with physicochemical parameters may be attainable by restoring or reducing connectivity to parent rivers and can be influenced by the development of forested wetland areas.
Contaminant transport through riparian wetlands
Year: Authors: Davidson G., Wren D.G., Walker W.G., Utroska S.G.
Riparian wetlands are perceived to be efficient scavengers of a wide variety of non-point source pollutants. This perception is based primarily on short-term studies, typically less than one year in duration, that have documented capture of contaminants entering a wetland. Little is known about the long-term fate of most sequestered contaminants. Preliminary results from a study of sediments deposited over the last century in lake-wetland systems in the Delta region of Mississippi suggest that sequestration of contaminants in riparian wetlands may not be permanent. At Sky Lake, an oxbow lake surrounded by agricultural lands and bordered by a cypress wetland, sediment cores were collected from the wetland and from a central open water area. Elevated Pb and As concentrations were found in sediments deposited approximately 80 years ago in only the open water environment. The most likely source of Pb and As is lead arsenate pesticide used in this area at the time these sediments were being deposited. Runoff from the surrounding fields passes through the wetland before reaching open water. Given the high affinity of Pb and As to solid surfaces, it is unlikely that either passed through the wetland without at least partial adsorption. Our hypothesis is that these contaminants were initially sequestered in the wetland when introduced in the late 1920’s and 1930’s, but subsequent seasonal flooding and aeration resulted in repeated remobilization and redistribution through the lake-wetland system. Permanent sequestration occurred only with burial in the perennially flooded open water environment. The work at Sky Lake is being expanded to other lake-wetland systems with similar geomorphology and history. Sediment cores have been collected from Hampton Lake, another oxbow lake in the Delta, to determine if a similar record is preserved.
Evaluating water supply needs in rebuilding the Mississippi Gulf Region
Year: Authors: Brown G.A.
In the months following Hurricane Katrina, the Mississippi Gulf Region faced a monumental rebuilding effort. One major component of this effort is insuring an adequate supply of potable water is available to satisfy residential, commercial, and industrial needs both in the near- and long-term. The Governor’s Commission on Recovery and Renewal recommended adoption of a regional approach for critical infrastructure. The Mississippi Department of Environmental Quality was tasked with the development of the Gulf Region Water and Wastewater Plan, a document which identified water, wastewater, and stormwater management needs within the 6-county Gulf Region and proposed projects to address those needs. With regard to water needs, existing sources of supply were identified and usage from these sources quantified to the extent practical. Information from several sources, including local entities involved in planning and development in the Gulf Region, was compiled to project water supply needs over the next two decades in terms of both quantity and location. Existing retail agents were evaluated for their ability to serve present and projected customers within their designated service area. From these sources, water supply projects were developed. The projects were conceived to both supplement existing systems and provide potable water in those key growth areas of the Gulf Region presently lacking adequate water supply infrastructure.
Bi-national harmful algal blooms observing system (HABSOS) and the phytoplankton monitoring network
Year: Authors: Beard R.H.
The Harmful Algal Blooms Observing System (HABSOS) is a regional coalition of U.S. and Mexican Federal and State agencies working together to study algal bloom events within the Gulf of Mexico Ecosystem. Algal toxins introduced into the ecosystem affect the health of humans and marine life, and disrupt social and economic activities. The coastal zone manager is challenged to monitor, assess, and forecast bloom events to minimize societal impact. A bilingual (Spanish/English) HABSOS web site an Internet tools have been developed to support this effort. Data entered into the system are available for display and analysis in the HABSOS Internet Map Service (www.ncddc.noaa.gov/interactivemaps/harmful-algal-blooms-observing-system-habsos). The HABSOS and Bi-National were developed and supported by U.S. Environmental Protection Agency (EPA) Office of Research and Development, EPA Gulf of Mexico Program, and the NOAA National Coastal Data Development Center (NCDDC). In 2007, NCDDC added the associated Phytoplankton Monitoring Network (PMN) a volunteer regional data management network to assist the HABSOS effort. PMN is an education and outreach program developed by NOAA’s National Ocean Service’s to engage school and community volunteer groups in phytoplankton sampling and identification and to raise awareness of harmful algal blooms. NCDDC partnered with PMN to create an end-to-end data management system for the volunteers. Members are provided an on-line data entry tool to submit data, and are then able to visualize and analyze their own validated data as well as from Network peers in an Internet Geographic Information System (GIS) environment. Approved data is mapped to (www.ncddc.noaa.gov/website/SEPMN/viewer.htm). NCDDC has partnered with the newest NOAA Cooperative Research Institute, the Northern Gulf Institute (Mississippi State University, University of Southern Mississippi, Louisiana State University, Florida State University, and Dauphin Island Sea Lab) to train and equip the volunteer organizations.
The Mobile River Basin: A review of physiographic, climatic, water quantity, and water quality characteristics
Year: Authors: Diaz-Ramirez J.N., Alarcon V.J., McAnally W.H., Martin J.H.
The Northern Gulf Institute (NGI) has been established with National Oceanic and Atmospheric Administrations’ (NOAA) Office of Oceanic and Atmospheric Research funding. The NGI is funding a three-year project since 2007 called "Watershed Modeling Improvements to Enhance Coastal Ecosystems"; the main goal of this project is to improve watershed-wide decision support for resource management agencies with a demonstration project in the Mobile River watershed. The objective of this presentation is to show a review of physiographic, climatic, water quantity, and water quality characteristics of the Mobile River basin. The 113,959-Km2 watershed drains waters in four states: Alabama, Mississippi, Georgia, and Tennessee with seven major subbasins (Coosa, Tallapoosa, Cahaba, Black Warrior, Tombigbee, Alabama, and Mobile). There are five Level III Ecoregions crossing the catchment: Coastal Plains, Appalachian Plateaus, Valley and Ridge, Piedmont, and Blue Ridge. The basin is mainly rural with the following land use distribution: forest (70%), pasture and hay (11%), cropland (8%), wetlands (6%), and urban (3%). This watershed is highly regulated with more than 100 dams. The Alabama Power generates hydroelectric power from 12 dams located in three subbasins: Black Warrior (Bankhead, Holt, and Smith dams), Tallapoosa (R. L. Harris and Martin dams), and Coosa (Mitchell, Jordan, Lay, Logan Martin, Walter Bouldin, Weiss, and H. Neely Henry dams). The Army Corps of Engineers operates 22 locks and dams in the Mobile River system. Water quality observed data from two U.S. Geological Survey stations, 02429500 Alabama River at Claiborne and 02469762 Tombigbee River, were analyzed. The drainage area of 02429500 and 02469762 stations represents 50% and 42% of the total watershed area, respectively. Almost thirty years (1974-2004) of discrete water quality data have been collected in these stations (around 200 samples). Cumulative distribution functions of total suspended sediments, total nitrogen, and total phosphorus were developed for each station. This entire physiographic, climatic, water quantity and water quality database is being used in hydrology, hydraulic, and sediment modeling evaluation of the Hydrological Simulation Program - FORTRAN (HSPF), the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model, and the Hydrologic Engineering Centers River Analysis System (HEC-RAS) model.
A water budget: Tenn-Tom Waterway from Whitten Lock to Heflin Lock and Dam
Year: Authors: McKee J.K.
The Tenn-Tom Waterway was completed in 1984, linking the Tennessee River to Mobile Bay via the Tombigbee River. Water from the Tennessee River watershed flows through Whitten Lock near Bay Springs, Mississippi, and merges with flows from the Tombigbee Watershed. Although the primary authorized purpose for the Waterway is navigation, now it is being looked to for surface water supply to keep up with current and future water demands in Northeast Mississippi. Before watershed managers can make well-informed decisions about permitting withdrawals, the amount of water available must be quantified-a water budget. This was attempted through the compilation of data into a spreadsheet schematic of the Tombigbee River and Tenn-Tom Waterway. Data were acquired through various methods and sources including Geographical Information Systems, USGS Streamflow Data, MDEQ and USACE personal communication, and the MDEQ EnSearch Engine. A meld of these data into the spreadsheet format transforms them into the volumetric discharges for different flow situations at locations along the river and waterway.
Characterization of water quality in unmonitored streams in the Mississippi Alluvial Plain, Northwestern Mississippi, May-June 2006
Year: Authors: Bryson J.R., Coupe R.H., Manning M.A.
The Mississippi Department of Environmental Quality is required to develop restoration and remediation plans for water bodies not meeting their designated uses, as stated in the U.S. Environmental Protection Agency’s Clean Water Act section 303(d). The majority of streams in northwestern Mississippi are on the 303(d) list of water-quality limited waters. Agricultural effects on streams in northwestern Mississippi have reduced the number of unimpaired streams (reference streams) for water-quality comparisons. As part of an effort to develop an index to assess impairment, the U.S. Geological Survey collected water samples from 52 stream sites on the 303(d) list during May-June 2006, and analyzed the samples for nutrients and chlorophyll. The data were analyzed by trophic group as determined by total nitrogen concentrations. Seven constituents (nitrite plus nitrate, total Kjeldhal nitrogen, total phosphorus, orthophosphorus, total organic carbon, chlorophyll a, and pheophytin a) and four physical property measurements (specific conductance, pH, turbidity, and dissolved oxygen) were determined to be significantly different (p < 0.05) between trophic groups. Total Kjeldhal nitrogen, turbidity, and dissolved oxygen were used as indicators of stream productivity with which to infer stream health. Streams having high total Kjeldhal nitrogen values and high turbidity values along with low dissolved oxygen concentrations were typically eutrophic (abundant in nutrients), whereas streams having low total Kjeldhal nitrogen values and low turbidity values along with high dissolved oxygen concentrations were typically oligotrophic (deficient in nutrients).
Influence of surface-water recharge on the potential for agicultural nutrient and pesticide transport to the Mississippi River alluvial aquifer, North
Year: Authors: Welch H.L., Dalton M.
In December 2006, the Agricultural Chemical Transport (ACT) topical team of the U.S Geological Survey National Water Quality Assessment (NAWQA) Program began a study in northwestern Mississippi to evaluate the influence of surface-water recharge on the occurrence of agriculturally related nutrients and pesticides in the Mississippi River alluvial aquifer. A series of nine piezometers was installed along a transect across the Bogue Phalia, a stream located near Leland, Miss., Washington County. Water levels were monitored continuously in nine piezometers and in one monitoring well approximately 1 mile north of the site. Local ground-water flow direction was determined using bi-annual water-level data collected by the Yazoo-Mississippi-Delta Joint Water Management District (YMD) in selected irrigation wells screened in the alluvial aquifer. Routine and event-driven water-quality samples were collected from 2006-2007 and were evaluated for major ions, nutrients, organic carbon, and physical parameters. In addition, water samples were analyzed for two commonly used pesticides in the area, atrazine and glyphosate. Regionally, flow in the alluvial aquifer tends to be toward the axis of the Mississippi Embayment, which is the Mississippi River. Local ground-water flow patterns were evaluated to determine potential movement of nutrients and pesticides from streams to the alluvial aquifer. Historically, water-quality results indicate that nutrients are present in ground water. Although pesticides have occasionally been detected in ground-water samples, their detections indicate that there is potential for anthropogenic contamination of the alluvial aquifer. Data collected as part of this study will be used to quantify surface-water recharge to the alluvial aquifer as a transport mechanism for nutrient and pesticide movement into the ground-water system.
Use of a field method for determining hydraulic conductivity in soils in the Bogue Phalia Basin in the Mississippi River alluvial plain.
Year: Authors: Rose C.E., Coupe R.H.
Interest in the determination of hydraulic conductivity for soils in the Mississippi River Alluvial Plain is spurred by the heavy use of agricultural chemicals on these highly productive soils and the potential for offsite movement of these chemicals. Ground-water models indicate that up to 5 percent of the precipitation recharges the shallow alluvial aquifer, indicating a potential pathway for movement of these chemicals into ground water. A field method designed to rapidly measure field-saturated hydraulic conductivity (Kfs) on soybean and cotton fields in the Bogue Phalia Basin was used to evaluate the potential for recharge through agricultural soils. This technique uses a portable falling-head, small-diameter, single-ring infiltrometer and an analytical formula for Kfs that compensates both for the falling head and for subsurface radial spreading. Measured Kfs values generally were higher than expected and vary more than four orders of magnitude from 1x10-2 to 5x10-6 cm/s. Hydraulic conductivity was shown to vary spatially within an agricultural field and temporally due to soil moisture conditions.
Sediment transport analysis using HEC-RAS 4.0
Year: Authors: Ramirez-Avilla J.J., Diaz-Ramirez J.N., Martin J.L., McAnally W.H.
The Hydrologic Engineering Centers River Analysis System (HEC-RAS) version 4.0 was used to simulate the transport of non-cohesive sediments in the Goodwin Creek Experimental watershed, Mississippi. HEC-RAS is one-dimensional in-stream model developed by the U.S. Corps of Engineers for simulating steady and unsteady flow, sediments, and water temperature. One month of observed data was used to setup and evaluate the model. Four sediment transport functions were evaluated: Ackers and White, Toffaleti, Englund and Hansen, and Laursen. The model predicted with acceptable accuracy the sediment transport (concentration, mass, and behavior) for the specified temporal and spatial conditions. The computational time step was the most sensitivity parameter for increasing the accuracy of the simulated results. However, the increase in accuracy increased the consumed time for the model by performing the computational analysis. Although Ackers and White function overestimated the sediment concentrations and sediment yield observed, it was the most descriptive function of the sediment transport behavior. Toffaleti’s sediment transport function underestimated the observed conditions and did not describe an accurate behavior of the sediment transport process. It would be some condition in the model routine which produced inconsistent results which the generated in other studies, where generally, Toffaleti’s estimations are higher than Ackers and White. Englund and Hansen, and Laursen functions significantly overestimated the observed conditions. HEC RAS also generated a spatial analysis of the different output parameters which permitted to identify specific conditions about the behavior and characteristics of the channel.
Sediment budget template applied to Aberdeen pool
Year: Authors: Sharp J.A., McAnally W.H.
The purpose of this work is to create a sediment budget template, with Aberdeen Pool on the Tennessee-Tombigbee Waterway as the demonstration site. USGS data are used to define sediment concentrations and flows. The USGS data are the basis for the Power Curve Program which defines the sediment behavior in terms of a power function. The second program, Tier 1 Program, uses the power curve coefficients along with the bankfull discharge to define the sediment fluxes. Thirdly, the Tier 2 Program uses power curve coefficients with daily flows to calculate daily sediment flux which are integrated over each year to calculate the yearly fluxes. From the sediment fluxes, a mass balance equation is implemented to estimate total deposition. Lastly, the computer program SIAM is used to estimate deposition amount. Comparison among the three different methods provides a best estimate of the final depositional approximation.
Vegetated swales and their effect on agricultural stormwater flow rates, a field verification of the FarmLatis Conservation Planning Tool
Year: Authors: Avery H., Schauwecker T.J.
Water quality is progressively becoming more important in the planning process. A field verification of the FarmLatis conservation planning tool represents research into technology that is for use in the conservation planning process. A program is being developed by researchers from Mississippi State University that are from the Forest and Wildlife Research Center, the Departments of Landscape Architecture, Civil Engineering, and Agricultural and Biological Engineering that integrates hydrologic modeling (HSPF) and Best Management Practice (BMP) implementation, called Latis (Wilkerson et al. 2006). FarmLatis represents an agricultural extension of the Latis decision support system. Latis and FarmLatis are intended to help developers and conservation planners implement Low Impact Development (LIDs) and conservation planning strategies into their site designs. The application of hydrological modeling is a natural extension of these planning processes. The modeling process can assist in determining the different design alternatives for a specific site and assess their effectiveness in maintaining and improving water quality. FarmLatis and Latis use modeling tools which predict the time-varying runoff and water quality of stormwater. Three sites located at Mississippi State University are being modeled and monitored. Sites one and two are swales located in pasture land with runoff from cattle and a gravel road. Site three is a swale located at the end of a plowed row crop field. The research sites address the following areas in the drainage swales at all three sites: a field verification of FarmLatis modeling results, Best Management Practice design, seeking the most effective approach of installing plants (buttonbush) and structures (check dams), and the improvement of the BMP modeling and cost parameters used within FarmLatis. Research at these farm sites are excellent test cases for the application of FarmLatis.
Nitrate in groundwater in a recharge area of Guarany aquifer in Brazil
Year: Authors: Cerdeira A.L., Paraiba L.C., Kataguiri K., Bolonhezi D., Gomes M.A., DeSouza M.D., Pereira A.S., Neto C.F.
The region of Ribeirão Preto City located in São Paulo State, southeastern Brazil, is an important sugarcane, soybean and corn producing area. This region is also an important recharge area (Espraiado) for groundwater of the Guarany aquifer, a water supply source for the city and region. It has an intercontinental extension that comprises areas of eight Brazilian states, as well as significant portions of other South American countries like Argentina, Uruguay, and Paraguay, with a total area of approximately 1,200,000 Km2. Due to the high permeability of some soils present in this region, the high mobility of the herbicides and fertilizers applied, and being a recharge area, it is important to investigate the potential transport of applied fertilizers to underlying aquifer. The cultivation sugar cane in this area demands the frequent use of nitrogen as fertilizer. This research was conducted to characterize the potential contamination of groundwater with nitrogen in the recharge area of groundwater. Seven groundwater sample points were selected in the Espraiado stream watershed, during the years of 2005 and 2006. Samples were collected during the months of March, July, and December of each year. Three replications were collected at each site. Groundwater was also collected during the same months from county groundwater wells located throughout the city. The following six wells were studied: Central, Palmares, Portinari, Recreio Internacional, São Sebastião, and São José. Nitrate water samples were analyzed by Cadmium Reduction Method. No significant amount of nitrate was found in the recharge, agricultural, area. However, nitrate levels were detected at concentrations higher than the Maximum Concentration Level (MCL) of 10mg/L in downtown, urban, well located away from agricultural sites with no history of fertilizer or nitrogen application.
Movement of water pollutants in Sardis Lake
Year: Authors: Gordji L., Surbeck C.J.
Comprising 39.9 million acres, lakes and reservoirs are a major water resource in this country. They provide drinking water and water supply for industry, irrigation, hydropower, and many recreational activities. Sardis Lake is a dammed reservoir in the state of Mississippi, located on the Little Tallahatchie River. This study is designed to evaluate the movement of water pollutants throughout Sardis Lake and to assess how different water quality parameters are related. The first part of this study is to compare levels of water quality parameters at different locations in Sardis Lake. A statistical package, SPSS, is used to analyze the data. The analyses of data were performed by two-tailed Pearson correlation. For the second part of this study a numerical model, CCHE2D, is used to examine the transport of pollutants in Sardis Lake. CCHE2D was developed by the National Center for Computational Hydroscience and Engineering (NCCHE) at the University of Mississippi. This two-dimensional system is used for unsteady, turbulent river flow, sediment transport, water quality evaluation, and chemical transport. Water quality data were obtained from the Mississippi Department of Environmental Quality (MDEQ). A digital elevation model for Sardis Lake developed by NCCHE was used to generate a structured mesh for the lake. By applying boundary conditions, initial conditions, and setting the model parameters, simulation is performed and the results are obtained.
River continuum concept and water quality stressor identification
Year: Authors: Johnson D.R.
During the last few years most states have been moving away from numeric water quality criteria and moving towards the use of Indices of Biological Integrity (IBI) to evaluate water bodies with regards to compliance with the Clean Water Act. IBIs function well with regards to determining compliance, but often fall short of identifying the stressors responsible for impairment. The Mississippi Department of Environmental Quality is in the process of developing a fishery IBI for the Yazoo Basin. A GIS database was used to generate land-use and stream data. This data coupled with expected fisheries information developed by applying the River Continuum Concept has identified some water quality stressors, and potentially could be used to identify other stressors.
Comparing index of biotic integrity scores to traditional measures of water quality: Exploring the causes of impairment in streams of the Mississippi
Year: Authors: Tietjen T., Ervin G.
The US Army Corp. of Engineers in conjunction with the Mississippi Department of Environmental Quality has worked to determine the quality of water in the streams of the Mississippi Delta region using an Index of Biotic Integrity (IBI) approach. This approach to water quality monitoring seeks to use information extracted from fish community composition and habitat parameters to provide an integrated and comprehensive picture of water quality that is reported to be superior to traditional grab samples analyzed for chemical water quality parameters. One difficulty encountered is that the Index of Biotic Integrity scores are based on a variety of fish community parameters, and therefore they cannot be directly related to specific pollutants or used to prescribe specific mitigation or restoration practices. We have collected periodic water samples from 20 of the sites which have previously been sampled and scored using the IBI approach. These samples will be analyzed for a variety of chemical (Nitrite+Nitrate-Nitrogen, Ammonium-Nitrogen, Soluble Reactive Phosphorus, Oxygen, pH), biological measures (Total Coliform bacteria, Fecal Coliform bacteria, Chlorophyll a, Chemical Oxygen Demand), and physical measures (suspended sediments, temperature). Overall this effort is attempting answer two questions: Can correlative relationships be developed between overall IBI scores and some combination of traditional water quality measurements? Can "classes" of pollutants be identified and correlated to IBI score ranges? Either of these answers will provide guidance need to make water quality improvements.
Effects of harvest management on bermudagrass yield and nutrient utilization in a swine-effluent spray field
Year: Authors: Read J.J., Fairbrother T.E.
Swine waste management plans often include the use of lagoon effluent for the production of bermudagrass [Cynodon dactylon (L.) Pers.], the predominant warm-season forage in the southeastern USA. Producing bermudagrass hay from fields receiving swine effluent provides both high quality forage for ruminant livestock and a means of exporting manure nutrients to reduce potential surface and ground water impairment. The objective of this study was to determine harvest management effects on annual forage yield and uptake of N and P by common bermudagrass. Research was conducted in 2001-2003 in a swine-effluent spray field on a commercial farm in northeast Mississippi on a Prentiss sandy loam. Small plots (2 x 4 m) were irrigated with 15 cm ha-1 effluent from April-October, which provided about 520 kg ha-1 N and 110 kg ha-1 P during the growing season. After an initial harvest of all plots in early May, summer growth was harvested at 4, 6, 8, 10, and 12 week intervals and at 3- and 9-cm cutting heights using a sickle-bar mower. The year x harvest interval interaction effect was significant (P<0.001) for P uptake because maximum values were obtained at the 10-wk interval 2001 and at the 6-wk interval in 2002 and 2003. This interaction may be explained by seasonal changes in plant maturity, effluent nutrient concentration, irrigation rate or the combined effect of these factors. The year x height interaction effect also was significant (P<0.05); however, harvesting at 3-cm height consistently increased P uptake by about 18% in 2001, 28% in 2002, and 29% in 2004, as compared to 9-cm cutting height. These results provide information to producers and land managers on methods to enhance the uptake of manure nutrients by bermudagrass, and thereby decrease potential losses of N and P from hay fields receiving swine effluent. If the goal is to produce a high quality forage, bermudagrass should be cut frequently (< 5-wk interval) and as tall as practical in order to harvest more leaf tissue. If the goal is maximum utilization of manure nutrients in the effluent, bermudagrass should be cut at 6-10 wk intervals as close to the ground as possible in order to maximize annual forage yield.
Assessing the risks to water bodies from nitrogen vs. phosphorus-based broiler litter strategy
Year: Authors: Adeli A., Brooks J.P.
The large amounts of poultry manure in localized areas and the high cost of implementing effective Best Management Practices (BMP’s) often favor disposal rather than utilization of manure. Continual application of poultry manure at rates providing more N and P than removed by crops can increase soil N and P to levels that are of environmental rather than agronomic concern. Over application can enhance potential movement of N as NO3 to ground water and P in surface runoff. This study was conducted in 2007 at R.R. Foil Plant Science Research Center, Mississippi State University on a Mariate silt loam soil to investigate how N- vs. P-based poultry manure to perennial forage crops affects nitrate and P leaching from the crop root zones, N and P in surface runoff, crop removal and soil accumulation of the nutrients. An experimental field with bermudagrass has been established. Poultry manure was applied meeting the N or P requirement of Bermuda grass; fertilizer and control treatments serve as comparison purposes. Treatments replicated three times. Pen lysimeters were used to collect leachate for determining nitrate and P leaching losses. Runoff collection devices were installed for estimating runoff losses of N, soluble P and suspended solids. A rainfall simulator was used to simulate precipitation events and following each rain event, runoff and leachate samples were collected for nutrient analysis. Seasonal nitrate and P distributions in the soil profile will be monitored. Yield and nutrient utilization efficiency will be determined. This project will generate comprehensive and quantitative N and P data in both leachate and runoff when manure is applied at two contrasting rates to forage based system. Such data will provide much needed information for devising and effective decisions on how best to manage the vast amount of poultry manure nutrients for protecting waters while sustaining animal agriculture.
Sensitivity analysis of simultaneous nitrification-denitrification process by simulation with activated sludge model number one
Year: Authors: Dey A., Magbanua Jr. B.S.
The National Weather Service (NWS) is responsible for issuing river and flood forecasts and warnings to mitigate the loss of life and property. Current NWS text-based products are utilized by emergency managers (EMs). One of the most often requested product from EMs is flood inundation mapping to show the areal extent of flooding. Flood inundation maps would translate the forecasted stages into inundation areas, making it easier for EMs to take action and alert the public. They would also prove invaluable to EMs in their outreach, mitigation, and educational efforts. By partnering with the Federal Emergency Management Agency (FEMA) and local communities, the NWS is developing flood inundation maps for their forecast locations. When a community performs flood studies to update FEMA Flood Insurance Rate Maps (FIRMs), much of the necessary data are available to develop flood inundation maps. For a small incremental cost above the cost to develop FIRMs, flood inundation maps at various stages above the NWS-established flood stage are being developed. This collection of maps will form a flood inundation map library that can be served up to the public via the Internet. The NWS has partnered with FEMA and developed flood inundation map libraries at about 15 locations across the country. Currently, work is ongoing to produce these maps for an additional 30 sites in the states that border the Gulf of Mexico. The NWS has established a web site and web structure to serve this data up to the public.
Phytomanaging Firing Range Soils Using Cyperus esculentus
Year: Authors: Butler A.D., Begonia M.F., Medina V.
Firing range contamination is an issue that challenges the United States Military. The success of our armed forces depends upon realistic live-firing range training that includes the use of munitions and weapons during tactical and strategic operations. Concerns have increased regarding environmental effects from testing and training activities on these sites. Because of incomplete combustion and detonation, explosive contamination has documented at some ranges and has resulted in restriction of training activities. <br><br> Two commonly used explosives, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and trinitrotoluene (TNT) have contributed to soil and groundwater contamination on and nearby firing range sites. Because live ammunition training is still needed, the cleanup of these contaminants may prove to be expensive. Also, applying environmental maintenance designed to support other uses could interfere with routine training and testing operations. To avoid high cost and site interferences, an alternative being considered is the use of native grasses to phytomanage military firing ranges. Phytomanagement involves the phytoremediation technology which uses live plants for in situ and ex situ remediation of contaminated soil, sludges, sediments and groundwater. Research studies have indicated that phytoremediation is effective which concludes that it could be a useful approach at active firing ranges. <br><br> The objectives of this study are to evaluate and develop a cost-effective management technology to control active range contaminant migration and promote on-site contaminant degradation. Our study uses Cyperus esculentus (Yellow Nutsedge) as its remedial tool. Outdoor lysimeter cells were designed to mimic a practical firing range setting. Natural rainfall is the main source of irrigation; however, rain assimilation will be performed if needed. Leachate and runoff from the soil surface are collected. The anticipated result of this research is to stabilize the contaminants and reduce the amount of RDX and TNT in the soil surface runoff and leachate.
Standardization of Thermal Desorption GC/MS Analysis for Polycyclic Aromatic Hydrocarbons and Comparison of Recoveries for Two Different Sample Matric
Year: Authors: Bathi J.R., Pitt R., Findlay R.
The analysis of PAHs in environmental samples involves sampling, extraction, concentration and final analysis using GC-MS. Traditional extraction of PAHs from a solid matrix, where much of the PAH reside, is a tedious and time consuming process. Thermal desorption (TD) can replace the traditional sample preparation step in the analysis scheme with a more efficient and direct method, which also eliminates the organic solvents used in the traditional extraction procedures, with the added advantage of significantly reducing the sample preparation time. This paper examines the recovery of standard PAHs solutions spiked on glass wool for different desorption times using TD techniques. Recoveries for desorption times ranging from 1 min to 20 min were studied. The peak areas obtained for individual PAHs increased as desorption time increased from 1 min to 15 min, while there was a decrease in peak areas as desorption times increased to 20 min. Therefore, the optimum desorption time for the highest recovery of PAHs was found to be 15 min. Coefficients of variation were calculated using the optimized desorption time for the PAH mix spiked on the glass wool substrate. It was found that low molecular weight and high molecular weight PAHs have high coefficients of variation (naphthalene 49%, Fluorene 24.2%, Dibenz(ah)anthracene 14.8%, Benz (ghi)perylene 15.5%), while the intermediate PAHs had much lower coefficients of variation (ranging from 0.5 % - 4.0%). The method response was tested for linearity by analyzing the glass wool spiked with five different concentrations of PAH mixtures, ranging from 0.01 to 20ng/uL. <br><br> The second part of the research examined the PAH recoveries from glass wool compared to Tenax spiked with PAH mixtures. This was performed by spiking the wool and 10 mg of tenax with 20ng/uL of the PAH mixture. The recovery of low molecular weight PAHs (having fewer numbers of rings) was larger in the case of Tenax than for the glass wool, whereas for the high molecular weight PAHs (having more rings), the recovery of PAHs from glass wool was larger than from the Tenax matrix.
Antibiotic resistant and pathogenic bacteria associated with rain runoff following land application of poultry litter
Year: Authors: Brooks J.P.
Poultry rearing in the United States is approximately a thirty million dollar per year industry. To produce this large number of product, a by-product such as poultry litter is inevitable. The land application of poultry litter as an organic fertilizer is an ideal choice for the disposal of this high nitrogen, high organic waste. However, some precautions must be observed, particularly with regard to potential rain-mediated runoff of litter-related microorganisms following any large-scale precipitation events, such as those common to the Mississippi area. To investigate this phenomenon, poultry litter application will be simulated in a controlled greenhouse environment. Litter will be applied to Bermuda grass (Cynodon dactylon) plots held within runoff trays designed to simulate environmental conditions, by simulating slope, soil type, and climate. A rainfall simulator will be used to simulate precipitation events. Rainfall will be simulated on a weekly basis for a total of 4 consecutive weeks. Following each rain event, runoff and leachate samples will be collected for microbial analysis. Soil will be collected prior to the commencement of the experiment and following experiment termination. Total Heterotrophic Plate Count bacteria, antibiotic resistant bacteria, fecal coliforms, enterococci, staphylococci, Clostridium perfringens, and Salmonella spp. will all be investigated using both cultural and molecular methods. Select pathogens, indicator, and heterotrophic plate count bacteria will be selected for further genus typing and antibiotic resistance. In ad ition to the litter applied runoff trays, control trays in which no litter will be applied and chemical fertilizer applications will be used as comparison controls. Results from this experiment will lead to future in field application studies, under environmental conditions. These experiments will then be used to identify optimal field conditions necessary to achieve decreased potential for microbial runoff and subsequently provide much needed information to the area of litter application.
The Invasive Status of Giant Salvinia and Hydrilla in Mississippi
Year: Authors: Robles W., Madsen J.D., Maddox V.L., Wersal R.M.
Giant salvinia (Salvinia molesta Mitchell) is a nuisance, free-floating aquatic fern that can double biomass in 10 days through vegetative reproduction. Hydrilla (Hydrilla verticillata (L.f.) Royle) is a perennial submersed aquatic plant that can propagate from stem fragments, turions, and subterranean tubers representing a triple threat for management methods. Both plants disrupt water bodies by affecting ecological interactions and halting boat traffic. Surveys were conducted during 2005-06 to detect the current status of giant salvinia and hydrilla in Mississippi. Giant salvinia was found at the Wedgeworth Creek located northeast of Leaf River near Petal in Forrest County. To date, giant salvinia has not escaped into the Leaf River. The biocontrol agent Cyrtobagous salviniae has been released at this site; however, no suppression and damage was noticed on the giant salvinia population. Hydrilla has been found in Lake Aberdeen, Aliceville Lake, Columbus Lake, Ross Barnett Reservoir, and Loakfoma Lake on the Noxubee National Wildlife Refuge (NWR). Management practices have been addressed for hydrilla control in the Ross Barnett Reservoir and Noxubee NWR. However, Lake Aberdeen, Aliceville Lake, and Columbus Lake are not currently under active management. Further surveys should be conducted to track giant salvinia and hydrilla spread over the reported sites as well as examine their presence in other of Mississippi water bodies.
Littoral Zone Plant Communities in the Ross Barnett Reservoir, MS
Year: Authors: Wersal R.M., Madsen J.D., Tagert M.L.
The Ross Barnett Reservoir is a 33,000 acre surface water impoundment created on the Pearl River near Jackson, Mississippi. The Reservoir is the primary source of potable water for the city of Jackson. It also provides recreational opportunities in the form of fishing, boating, water sports, and onshore camping and hiking; activities that bring revenue to the state. In recent years, non-native aquatic macrophytes have increased in distribution, impeding navigation, fishing, and reduced the aesthetics of waterfront properties. The Pearl River Valley Water Supply District requested assistance in developing and implementing a long term management plan for the Reservoir. Prior to developing and implementing lake-wide management programs, reservoir-wide surveys were needed to assess the current distribution of plant communities in the Reservoir. For this reason, we conducted a whole-lake survey in June 2005 to assess the distribution and abundance of plant communities in the Reservoir. In October 2006 a survey of the littoral zone (water depths of = 10 feet) was conducted based on the points sampled in 2005. A plant rake was deployed at each of the 508 points visited. Species distribution was mapped using handheld computers outfitted with GPS receivers, and data stored in database templates using Farm Site Mate software. Areas of increased plant occurrence were in the upper Reservoir, Pelahatchie Bay, and along the eastern shoreline. A total of 21 aquatic or riparian plant species were observed growing in or along the shoreline of the littoral zone. American lotus and water primrose were the most common plant species observed in the littoral zone (17.7 % and 7.4% respectively). Non-native plants included alligatorweed (3.9%), waterhyacinth (2.9%), and hydrilla (0.6%). Bladderwort, a native submersed aquatic plant was also observed (0.4%) for the first time. Overall, species distribution was lower during October 2006 than in 2005.
Common reed: Phragmites Australis (Cav.) Trin. Ex. Steud: Life history in the Mobile River Delta, Alabama
Year: Authors: Cheshier J.C., Madsen J.D.
Common reed (Phragmites australis) is a non-native invasive perennial grass that creates a nuisance in aquatic and riparian environments across the United States. The ability of common reed to reproduce quickly combined with its ability to cycle nutrients has made it an aggressive invader of riparian and wetland ecosystems. Common reed often forms monotypic stands that displace native vegetation more desirable as wildlife food and cover than common reed. Common reed has been differentiated into multiple haplotypes, two haplotypes being native to North America, and a non-native, European haplotype. The European haplotype is of concern due to its ability to out compete native vegetation, alter hydrology, and change community structure of aquatic and riparian habitats. In order to help maintain native habitats and manage and populations of common reed in the United States, a complete understanding of its life cycle is needed. Twelve samples were taken from four sites in Mobile River Delta, AL from January 2006 until December 2006. Above ground biomass allocation is highest from July through September with a high of 2.9 kg/m2. Below ground biomass allocation was highest from May through August with a high of 2.7 kg/m2 in May. This understanding will provide insights into the relationships between common reed and the environment as well as to guide management strategies.
Ecologically-based Invasive Aquatic Plant Management: Using Life History Analysis to Manage Aquatic Weeds
Year: Authors: Madsen J.D.
Invasive plants are increasingly recognized as a major problem in conserving and managing natural resources. Invasive aquatic plants not only threaten the diversity and functioning of aquatic, wetland, and riparian areas, but also contribute to flooding and reduce irrigation water flow. Management of these species has often focused on an engineering approach, either with direct herbicide application or mechanical removal, with little thought to the biology and ecology of the target species. I will demonstrate how knowledge of the life history of the target plant can greatly enhance management effectiveness using five examples: waterchestnut (Trapa natans L.), curlyleaf pondweed (Potamogeton crispus L.), Eurasian watermilfoil (Myriophyllum spicatum L.), hydrilla (Hydrilla verticillata (L.f.) Michx.), and waterhyacinth (Eichhornia crassipes (Mart.) Solms). For these analyses, I utilize studies that have focused on seasonal biomass allocation, carbohydrate storage, and propagule production. Waterchestnut is an annual, reproducing from seed. Successful long-term management must focus on preventing seed production. Curlyleaf pondweed is an herbaceous perennial, which oversummers using a turion. In this instance, management timing was critical in preventing turion formation and depleting the turion bank. Eurasian watermilfoil is a widespread evergreen perennial; management techniques can utilize the lack of resistant dormant propagules, as well as examining the timing of carbohydrate storage low points in selecting the best timing and management technique. Hydrilla uses several diverse life history strategies and is found as at least two distinct biotypes in the United States with very different phenologies. Understanding the differential response of the biotypes to the environment is one component to a successful management strategy. Waterhyacinth, a tropical plant, has shifted its life history pattern in subtropical and temperature zones. For all invasive plants of natural habitats, an understanding of the plant life history is vital to successful management.
Activities of the U.S. Geological Survey related to total nitrogen and total phosphorus trends and modeling in surface waters of the Lower Mississippi
Year: Authors: Rebich R.A.
The U.S. Geological Survey recently completed an assessment of trends in total nitrogen and total phosphorus concentrations and loads for the period 1993-2004 for surface waters in the Lower Mississippi (including the Arkansas-White-Red) and the Texas-Gulf River Basins. This assessment was part of a national effort to complete similar trend analyses for eight different regions in the United States as part of the U.S. Geological Survey National Water-Quality Assessment Program. Preliminary results indicated few trends in total nitrogen and total phosphorus data and no regional patterns where trends were observed during the study period. Decreasing trends in total nitrogen likely were an artifact of decreasing trends in flow. Increasing trends in total nitrogen were attributed to point source discharges (that have not been improved) and to areas where animal feeding operations (poultry and cattle) increased during the past decade. Decreasing trends in total phosphorus were attributed primarily to improvements in point source discharges, such as installation of advanced treatment facilities. Most of the increasing trends in total phosphorus were attributed to point sources (that have not been improved) and to animal feeding operations (poultry, swine, and cattle), similar to increasing trends in total nitrogen.<br><br> The trends assessment was focused at locations where State and Federal agencies collect flow and nutrient samples as part of routine monitoring efforts. However, information about trends in nitrogen and phosphorus concentrations and loads also is needed at other locations where such information does not exist. Future efforts will focus on development of a Spatially Referenced Regression on Watershed Attributes (SPARROW) model to estimate total nitrogen and total phosphorus loadings at non-sampled locations in the study area. The SPARROW model is a non-linear regression model using constituent loads at known locations as dependent variables and spatially-derived source data (coupled with land-to-water and aquatic transport functions) as independent variables. Source data could include nitrogen from atmospheric deposition, fertilizer use, and manure applications. The SPARROW model is based on a digital stream network (for this effort, the U.S. Environmental Protection Agency Enhanced River Reach File 1 network will be used) and catchments derived from digital elevation data. Once calibrated, the SPARROW model can also be used to simulate potential changes in the study area such as population shifts, improvements in point sources, and improvements in agricultural best management practices.
The Geology of Ground Water in Mississippi Revised
Year: Authors: Dockery III D.T.
A twelve-paged paper first published in the 32nd Annual Mississippi Water Resources Conference, April 23-24, 2002, Proceedings, summarizing the geology of ground water in Mississippi, is revised in a commentary on the importance of ground water to the state’s historical and present-day development. The presence of shallow aquifers accessible by well digging was responsible for the location of many communities and for the transportation routes that tied these communities together. Today ground water is still one of the most important factors in community development. Ground water accounts for 80% of the state’s water supply and more than 93% of the state’s drinking water; only 3 of the state’s 1,535 public water systems utilize surface water. Over 100,000 acres of farm-raised channel catfish ponds use ground water exclusively, and many farmers are dependent on ground-water supplies for irrigation. Mississippi’s most valuable aquifers by rank include the (1) Mississippi River Valley Alluvium, (2) Miocene, (3) Wilcox, (4) Sparta, (5) Lower Cretaceous and Tuscaloosa, (6) Cockfield, and (7) Eutaw-McShan, (8) Coffee Sand, (9) Paleozoic (lumping the Devonian, Mississippian, and Pennsylvanian), (10) Ripley, (11) Citronelle-High Terraces, (12) Oligocene, and (13) Winona-Tallahatta aquifers.
Supply and Demand: The Effects of Development on the Hydrology of Lake Victoria
Year: Authors: Songa P.A., Sewagudde S.M.
The water level of Lake Victoria has been falling since 2001seriously affecting Uganda’s economy. Since 2004 power generation has fallen due to reduced reservoir capacity. The 2004 Net Basin Supply (NBS) was only 37 MCM/day or 49% of the long term NBS. Total outflow was 113 MCM/day in 2004, corresponding to a NBS exceeded 3 in 10 years. This unhinged the equilibrium of the system, highlighting the unsustainable use. At such outflows, the hydropower reservoir could be depleted in 5 to 6 years. If the next years are predominantly dry or wet this estimate would decrease or increase respectively. Returning to natural flow could lower energy production by up to 50% - 60% over the next two years. Planning and implementation of developments on Lake Victoria to date have not taken account of the multiple users of the lake, a factor that has contributed greatly to the crisis. Future developments should therefore consider all the competing uses by incorporating Integrated Water Resources Management (IWRM).
National Weather Service Expansion of Hydrologic Services in Mississippi
Year: Authors: Reed D.B.
The National Weather Service is expanding and modernizing hydrologic services in the state of Mississippi. The NWS is developing a modeling system for the coastal areas that links our current hydrologic models with hydraulic and oceans models to provide better forecasts. Flood inundation maps will be developed to provide emergency managers information on areas that will be flooded at specific river levels. Enhanced modeling procedures will be tested at selected locations within the state.<br><br> As a pilot project on the Pascagoula River, the NWS is developing a hydrodynamic model simulating the water levels in the Gulf of Mexico and a 2-dimensional hydraulic model for the Pascagola River drainage below Merrill, MS. These models will be linked to the NWS hydrologic model resulting in model simulations for this area that incorporate the effects of riverine flooding and the effects of tides and storm surge from hurricanes. This system should allow the NWS to provide more accurate forecast at existing sites and easily implement forecasts at additional sites.<br><br> For selected locations in Mississippi, flood inundation maps will be prepared. At one-foot intervals from flood stage to the flood of record, a hydraulic model will be run to determine the water surface elevations for a steady state flow condition. From these elevations using geographic information systems (GIS) technologies, maps depicting flood inundation areas will be developed. These maps will be provided to local and state emergency managers for use in determining evacuation areas.<br><br> As a test, the NWS will implement additional enhanced hydrologic modeling procedures. For small watersheds, the Sacramento Soil Moisture Accounting Model will be tested on an hourly time step. A distributed hydrologic model will be calibrated and tested on a small watershed in Mississippi. In addition to model development, the NWS will conduct outreach and training with local emergency managers and officials on these new and improved techniques.
Mapping Hurricane Katrina Peak Storm Surge in Alabama, Mississippi, and Louisiana
Year: Authors: Turnipseed D.P., Wilson Jr. K.V., Stocker J., Tyler D.
Hurricane Katrina produced the largest peak storm surge observed in the Gulf of Mexico. Hurricane Katrina made landfall on the northern Gulf of Mexico Coast early on August 29, 2005, first slamming into the Mississippi River delta near Buras, Louisiana, and then overwhelming the Pearl River delta at the Louisiana-Mississippi border. Riverine flooding from Katrina-induced rainfall was minimal in the region, but the storm devastated the Gulf of Mexico coastal region of southeastern Louisiana, Mississippi, and Alabama. Katrina has been estimated to have caused the loss of more than 1,800 human lives, and about $81 billion in damages.<br><br> In the wake of Katrina’s destruction, high water marks--representing Katrina’s peak storm surge--were flagged, surveyed, and documented by teams representing the Federal Emergency Management Agency, the U.S. Geological Survey, U.S. Army Corps of Engineers, and others. Peak storm surge of about 29 feet was documented near Bay St. Louis, Mississippi, confirming that Katrina was more than 4 feet greater than Hurricane Camille (previous largest known peak storm surge).<br><br> In the months that followed, the U.S. Geological Survey began developing an internet-based geographic information system (GIS) application that will allow a user to pinpoint depths of the Hurricane Katrina peak storm surge in the affected states. Pre-Katrina flown Light Detection and Ranging (LiDAR) data were seamlessly conjugated to form a high-resolution digital elevation model (DEM) that served as the base for the mapping. The Federal Emergency Management Agency also contributed pre-Katrina LiDAR-based DEMs and inundation polygons, and high water marks for Louisiana, Mississippi, and Alabama. These data were supplemented by available U.S. Geological Survey, U.S. Army Corps of Engineers, and Interagency Performance Evaluation Task Force tide gage and high water mark data to compile high water elevations at more than 1,500 locations to be used in generating a peak storm surge GIS coverage for the affected coastal region. In addition, the U.S. Geological Survey Earth Resources Observation and Science Center obtained U.S. Army Corps of Engineers Mobile District post-Katrina LiDAR for further use in computing planform changes of barrier islands/coastlines in the region and developing methods to estimate debris volume caused by the storm.
Mississippi Benthic Macroinvertebrate Tolerance Values for Use in Surface Water Quality Assessment
Year: Authors: Hicks M., Bressler D.W., Stribling J.B., Paul M.J.
Conceptually, tolerance values are meant to represent the ability of aquatic organisms to survive in the presence of known levels of various types of water quality pollution. Operationally, they describe the relative abundance and co-location of organisms and pollutants. These numeric values are used to calculate assemblage level tolerance metrics that are commonly incorporated into indices of biological integrity. Defensibility of water quality assessments using tolerance value metrics depends, in part, on how individual tolerance values are developed. We derived tolerance values using an approach that attempted to minimize subjective circularity and maximize objectivity, by using abiotic characteristics of aquatic ecosystems to define gradients of water quality. Also, because most cases of water quality impairment involve multiple stressors at various levels in a given system, we used an approach that combines multiple physical and chemical characteristics into a single general stressor gradient. In this paper, we describe the development of tolerance values for benthic macroinvertebrate taxa collected from 455 wadeable stream sites throughout Mississippi, except the Mississippi Alluvial Plain (Mississippi River Delta). Principal components analysis (PCA) was used to develop a gradient that incorporated direct (in-stream physical and chemical) and indirect (land use) stressors, which was then scaled from 0-10. Weighted averaging of the relative abundance of each taxon was used to assign tolerance values based on the point of greatest relative abundance along the stressor gradient. Tolerance values were derived for 324 of the 567 taxa collected from across all sites, and primarily represented sensitivity to habitat, sediment loading and hydrologic alteration, and increased nutrient concentrations. We suggest that this approach could be used in other areas of the country to develop new tolerance values or refine existing ones, and may be a useful approach for other taxonomic groups.
Water Quality Modeling in Support of the Mississippi Sound Coastal Improvement Program
Year: Authors: Zakikhani M., Dortch M.S., Noel M.R., Kim S.C., Cerco C.F., Luong P.V., Chapman R.S.
Mississippi Sound of the northern Gulf of Mexico extends from Lake Borgne in Louisiana on the west to Mobile Bay in Alabama on the east. Cat, Horn, Petit Bois, and Dauphin are the main islands. The total surface area of Mississippi Sound is approximately 500,000 acres; 25 percent is classified as near shore habitat with less than two meters (6.5 feet) deep, and 75 percent is offshore habitat. <br><br> In response to major damages on the Mississippi coast caused by Hurricane Katrina, Congress has directed the U.S. Army Corps of Engineers to conduct the Mississippi Sound Coastal Improvements Program (MSCIP), which is an analysis and design for comprehensive improvements, or modifications to existing improvements, in the coastal areas of Mississippi in the interests of: (1) hurricane storm damage reduction, (2) prevention of saltwater intrusion, (3) preservation of fish and wildlife, (4) prevention of erosion, and (5) other related water resource purposes. Several measures are under consideration for restoring resources along the coast including: construction of dunes, seawalls, and levees on shore; development of surge mitigation measures; wetland and ecosystem restoration; barrier island and beach restoration; and freshwater diversion.<br><br> Mathematical models are being used within MSCIP to help evaluate the effects of barrier island restoration and freshwater diversions. This paper describes the application of a three-dimensional water quality model of the Mississippi Sound region to evaluate the impacts of freshwater diversion alternatives on water quality.<br><br> The water quality model (WQM), which is based on the CE-QUAL-ICM water quality model code, is coupled to output from a three-dimensional hydrodynamic model of the region, which is based on the CH3D hydrodynamic model. The version of CH3D with sigma coordinates in the vertical dimension is being used. The model grid extends seaward beyond Chandelier Island and includes Mobile Bay, Lake Borgne, Lake Pontchartrain, the Inner Harbor Navigation Channel of New Orleans, and the Mississippi River Gulf Outlet channel. <br><br> Predicted water quality constituents, including nutrients, phytoplankton, dissolved oxygen, temperature, salinity, and underwater light intensity, are being evaluated for each alternative and compared to modeled existing, baseline conditions to assess relative changes. Output from the model also will be available for use in habitat quality evaluations.
Fluctuating Asymmetry and Condition in Fishes Exposed to Varying Levels of Environmental Stressors
Year: Authors: Zuber B., Schaefer J.F.
The ability of an organism to combat developmental stress is known as developmental stability which can be assessed by measuring fluctuating asymmetry. Fluctuating asymmetry (FA) is the variation in bilaterally symmetrical traits. Deviations in bilateral traits from perfect symmetry may point to developmental stress. Environmental factors or stressors such as chemical pollution have been shown to decrease developmental stability and increase levels of FA in several studies, but links between FA and condition as a measure of fitness in the literature are rare and needed. <br><br> The purpose of this study is to determine if fluctuating asymmetry (FA) and correlates of fitness are good indicators of stress. Sites were selected at approximately 3, 6, 12, and 26 kilometer increments upstream and downstream from the Leaf River Pulp Mill, New Augusta, MS. Collections of approximately twenty fish from each of three species: the longear sunfish (Lepomis megalotis), the blacktail shiner (Cyprinella venusta), and the highfin carpsucker (Carpiodes velifer), were made in early summer, late summer, and late fall of 2006. Several morphometric measurements were taken from each fish to determine the degree of FA. These included lateral line scale count, pectoral and pelvic fin ray count, length of longest pectoral fin ray, eye diameter, and head length. Gonadosomatic index (GSI), percent lipids, fecundity, and length/weight residual were measured as correlates of fitness.<br><br> The purpose of this study is to address the following questions: 1) Is there any difference in measures of FA and condition that correlate with position (upstream or downstream) from the source? 2) Is there any difference in measures of FA and condition that correlate with water column position of fishes?
Water Quality and Floristic Quality Assessments of the Big Sunflower River Following Streamflow Augmentation using Groundwater
Year: Authors: Tietjen T., Ervin G.
The Big Sunflower River is listed on the EPA Section 303(d) list of Impaired Waterbodies of Mississippi. Contributing to the decline in conditions in this system are the substantial decreases in base flow during the late summer and fall as groundwater levels decline. In an attempt to improve water quality and ecological conditions the Yazoo Mississippi Delta Joint Water Management District has begun supplementing flows during this critical period using groundwater. To assess the impact of streamflow augmentation we evaluated water quality trends through the 2006-2007 pumping period and assessments of the quality of the riparian plant community. Measurements of water quality (Temperature, Dissolved Oxygen, pH, Specific Conductance and Turbidity) were made at 11 locations on the Sunflower River between Indianola and North Clarksdale, at one location associated with the augmentation pumps and 1 location along the channel used to funnel pumped water to the Sunflower River. In general water quality was better above Clarksdale, with improvements in dissolved oxygen concentrations associated with increased flows and decreased temperatures. The riparian plant community was analyzed over a more focused portion of the upstream drainage basin with 2 sites south of Clarksdale, 2 sites north of Clarksdale and 1 within the city itself. Clarksdale represented a clear break in pant composition with higher numbers of moncots, invasive species and weedy early succession species encountered upstream (North) of Clarksdale. Taken together there is some indication that supplementing natural stream discharge may have beneficial impacts on water quality in the near term and in broader measures of ecosystem quality in the long term.
Aquatic phytoremediation of CCA and copper contaminated water
Year: Authors: Keith C., Borazjani H., Diehl S.V., Prewitt M.L., Su Y., Han F., Baldwin B.S.
The removal of selected metals by duckweed (Lemna minor) and parrotfeather (Myriophyllum aquaticum) from a simulated aqueous environment contaminated with Chromated Copper Arsenate (CCA) and copper sulfate was studied in a controlled laboratory experiment. The duckweed and parrotfeather’s tissues were analyzed to evaluate the removal of copper (Cu), chromium (Cr), and arsenic (As) from CCA contaminated water (125 mg/L Cu, 220 mg/L Cr, and 205 mg/L As) and from copper sulfate contaminated water (60 mg/L Cu) over a 7 day period. The vigor of the plants was also recorded during this period. The results showed that the duckweed and parrotfeather both removed the metals from the water in each experiment. For the CCA contaminated water study, duckweed removed approximately 60% of each metal from solution while parrotfeather removed approximately 45% of each met al For the copper contaminated water study, duckweed removed approximately 85% of the copper concentration from solution while parrotfeather removed approximately 77% copper from solution. As for the vigor of the plants in the CCA study, duckweed remained rather healthy throughout most of this study. Parrotfeather sharply declined in vigor after two days into experiment. In the copper study, both plants remained fairly healthy through the duration of the experiment.
Effects of Attenuation and Dispersion Factors on Tebuthiuron Leaching Simulation
Year: Authors: Spadotto C.A., Matallo M.B., Gomes M.A., Luchini L.C., Cerdeira A.L.
Differences on response of mathematical models on herbicide leaching in the environment can occur due to the models and their limitations, mainly when using soil lysimeters. Tebuthiuron is a herbicide used in sugarcane crop and is applied in the recharge area of the Guarany aquifer in Brazil, one of the largest in the world. This study was conducted to compare the leaching potential of the herbicide within lysimeters using sandy soils of the Espraiado watershed in the recharge area from the region of Ribeirao Preto, SP, Brazil. The traditional Attenuation Factor (AF) model was used at various soil layers, adding a Dispersion Factor (DF) to the model. The fitness of the model was good for the total amount of tebuthiuron leached, but not for the rate of leaching. The model overestimated the level of herbicide leaching at 100 days after application, but the final concentration leached with the water was as predicted by the model.
Conservation Planning integrating site assessment and hydrologic modeling at the Mississippi State University Dairy Unit, Sessums, MS
Year: Authors: Schauwecker T.J., Murdock J., Collins K.
Reducing non-point source pollution associated with agricultural production is a high priority for policy makers and researchers. The test case of a 10-acre dairy farm headquarters was used to compare hydrologic modeling outcomes using HSPF to evaluate before- and after-installation effects of Best Management Practices (BMPs). The test site is a part of the Mississippi Agricultural and Forestry Experiment Station Dairy Unit, an 880-acre facility consisting of a dairy production facility, pasture, row crop and riparian forest in northeast Mississippi. The MAFES Dairy Unit is adjacent to Catalpa Creek in the Tibbee Creek watershed. Catalpa Creek was evaluated to determine its condition before research into BMP implementation began, so that baseline data can be compared to conditions following future improvements. After an extensive site assessment of the production headquarters, opportunities for improving runoff were explored, and included the design of a vegetated swale that would slow runoff from the dairy production site and act as a buffer in the event of an overflow from adjacent treatment lagoons. HSPF was used to evaluate the effectiveness of this and other BMPs that were placed in the landscape. Future work and research will evaluate the entire site and include cost/benefit analyses of BMPs that are identified as potentially beneficial to water quality, control of water quantity, and increase wildlife habitat. The Conservation Planning process will be improved through the use of these tools, which allow multiple scenarios to be tested for their efficacy before final decisions are made as to land management practice.
Bacterial source tracking of a watershed impacted by cattle pastures
Year: Authors: Prewitt M.L., Phelps C., Cox M., Evans R., Diehl S.V.
Pathogenic microorganisms introduced by cattle may be transported to distant locations via watershed runoff. Escherichia coli, Enterococcus spp., and Streptococcus spp. are a few species present in runoff from land impacted by humans, cattle, and wildlife. Initial data revealed that E. coli concentrations in water were greater in areas impacted by cattle than by humans. And, wildlife contributed greater concentration fluctuations than either humans or cattle. When cattle were removed from a pasture, the bacterial concentrations rapidly decreased; however, slight variations in cattle herd size did not appear to significantly influence these counts. Amplified fragment length polymorphisms (AFLP) and repeated-sequence polymerase chain reactions (rep-PCR) were molecular techniques used in this study to assess the impact of several cattle pastures on one rural communities watershed system. Preliminary REP-PCR results estimated that 13% of E. coli in pasture waters originated from cows.
Effect of Swine Effluent Application Rate and Timing on Nitrogen Utilization and Residual Soil Nitrogen in Common Bermudagrass
Year: Authors: Read J.J., Brink G.E., Adeli A., Thomas J.G.
Frequent summer precipitation may delay the application of swine effluent to bermudagrass [Cynodon dactylon (L.) Pers.] until late summer or early fall. A concern with late-season irrigations is declining day length and air temperatures in fall greatly reduce the growth and nutrient uptake of this warm-season forage crop. Field studies were conducted in 2000 and 2001 near Pheba, MS on a Prentiss sandy loam soil (coarse-loamy, siliceous, semiactive, thermic Glossic Fragiudult) with no known history of effluent application. The objectives were to determine if irrigation rate and timing influence crop N utilization and residual NO3-N in the soil profile. Small plots were arranged in completely randomized design with four replicates. Effluent was applied at 10 and 20 cm ha-1 (about 260 and 480 kg ha-1 N, respectively) during four spray seasons: April to September (full season), April to May, June to July, and August to September. Soil was sampled in fall and spring to estimate the amount of N not recovered by forage. Application of 20 cm effluent in April-May, June-July, and April-Sept treatments resulted in the greatest annual forage yield of about 11.5 and 18.1 Mg ha-1 in 2000 and 2001, respectively; the corresponding values for N uptake were 306 and 335 kg ha-1. Averaged across rates, the Aug-Sept treatment had the lowest N utilization efficiencies of 55% in 2000 and 34% in 2001. Application of 20 cm effluent in Aug-Sept treatment increased residual soil NO3, particularly in fall 2000 and spring 2001. Nitrogen in swine effluent applied in fall is less likely to be utilized by common bermudagrass due to either dry summer conditions or declining growth rate.
Effects of Broiler litter Management on Runoff N and P in Bermudagrass Forage Based System
Year: Authors: Adeli A., Brooks J.P., Rowe D.E., Miles D.M.
Management of broiler litter to provide nutrients for crop growth has generally been based on crop N requirements. Because broiler litter has a lower N/P ratio than harvested crops, N-based broiler management often oversupplies the crop-soil system with P, which can be lost into the environment. This study was conducted in 2005 and 2006 at Mississippi State University Plant science center at South farm to investigate the effects of nitrogen vs. phosphorus based broiler litter application on bermudagrass [Cynodon dactylon (L.)] dry matter yield, N and P uptake, leaching and runoff nutrients and soil P accumulation. Treatments included N-based broiler litter rate, combination of P based broiler litter with supplemental N, chemical fertilizer N and P at the recommended rate for comparison purposes, and the control with no nutrient inputs. Nitrate concentrations in leachate collected from chemical fertilizer and N based broiler litter treatments averaged 26 mg NO3-N L-1 and no difference was obtained between treatments. Regardless of treatments, total P loss in the leachate was in very small quantities indicating minimal downward movement of P. However, P losses in runoff from N based broiler litter was significantly greater than P based treatment. In the top 15 cm of soil in plots receiving the N-based treatment, soil test P increased by 64% from 20 to 57 mg kg-1. Nitrogen- and P-based broiler litter application did not differ in supplying nutrients for crop growth. However, the N-based broiler litter led to greater accumulation of soil test P in the top surface 15 cm of soil as compared to P-based broiler litter. Surface soil P accumulation has implications for increased risk of off-field P movement which may contribute to eutrophication of water bodies.
Bee Lake Watershed Restoration Project
Year: Authors: Cooke T.
Bee Lake, a historical Ohio River oxbow, is located in Holmes County, Mississippi. The 11,870-acre watershed is dominated by row crop agriculture and feeds the 1,400-acre lake during most of the year. Annual backwater flooding also reaches Bee Lake as the Yazoo River floods into Tchula Lake and then backs into Bee Lake. Standard agricultural practices and the highly erosive nature of the soils found in the watershed have cause significant sediment loading in Bee Lake. Since intensive agriculture began in the watershed, the historical lake depth has been reduced by 50%. <br><br> Listed on the 1996 Mississippi 303(d) list of impaired waters, TMDLs for nutrients, organic enrichment, low dissolved oxygen, pesticides, and sediment were developed for Bee Lake. Because of these impairments and the lake’s popularity among fishermen, the Mississippi Department of Environmental Quality - Yazoo Basin Team prioritized Bee Lake for future restoration efforts.<br><br> In 2005, the Bee Lake Watershed Implementation Team (WIT) was formed. This team included 42 individuals, of which 27 were natural resource professionals and 15 were landowners from the watershed. This team identified all natural resource and related concerns in the watershed. In order of priority, the identified concerns included (1) Sediment and Turbidity, (2) Lake Level and Water Supply, (3) Noxious Aquatic Vegetation, (4) Organic Enrichment, (5) Future Development, (6) Fisheries Management, and (7) Lake Access. After all concerns were identified, solutions and funding mechanisms were proposed.<br><br> The efforts of the Bee Lake Watershed Team were used to develop a comprehensive Bee Lake Watershed Implementation Plan (WIP). The plan was designed to address all concerns identified by the WIT. The plan included implementation plans for each item, funding sources, and a timeline for restoration. Major components of the plan included BMP installation and maintenance to address priority concerns, water quality monitoring, and educational outreach.<br><br> Implementation of structural measures began in the spring of 2006. By 2007, all aspects of the WIP will be implemented. The goal of implementation will be to reduce sediment loading by 35%-67% per year, reduce nitrogen loading by 70% per year, reduce phosphorous loading by 33% per year, and reduce DDT and Toxaphene loading by 33% per year. If these goals are met, Bee Lake will be removed from the 303(d) list of impaired waters and the DDT/Toxaphene fish advisories will be lifted. Other related items that will also be addressed include: rebuilding the weir to stabilize lake levels for increased water storage capacity for surface water irrigation, control of noxious aquatic weeds in the lake, establishment of a homeowners association to control development, improve fisheries through lake specific creels and slot limits, and the addition of a new boat ramp to increase lake access for the public.
Pesticide Presence and Concentrations In Surface Waters of Selected Lakes and Reservoirs (<500 acres) of Mississippi
Year: Authors: Cooper C., Smith Jr. S., Folmar H., Testa III S.
Surface water from 46 small (100 to < 500 acres) lakes and reservoirs located throughout Mississippi was sampled to test for presence and concentration levels of eighteen current-use or residual pesticides or their breakdown products. Each lake was sampled an average of five times from November 4, 2004 to October 6, 2005. In all, 3,988 analyses were performed, and the overall detection rate was 13%. The most frequently detected compound was DDT which exhibited an 85% detection rate. Fortunately, all concentrations were below 0.25 ug/L. Dieldrin, which had an approximate 34% detection rate, had no detections above 0.05 ug/L. The next three most commonly detected compounds were breakdown products of DDT and fipronil. The herbicide 2,4-D was commonly detected, and 13% of tested samples were quantifiable above 1.0 ug/L, with the highest observed concentration being 2.75 ug/L. Atrazine, the seventh most often detected compound, had the highest observed single concentration (14.47 ug/L) of all compounds tested and had an average concentration of 0.125 ug/L. Metolachlor was the only other compound detected at a concentration greater than 1.0 ug/L. Pendimethalin was the only compound not detected in any samples at any of the lakes. Butler Lake and Long Creek Reservoir both had 13 compounds detected. Only two pesticides were detected at Davis Lake, Filter Lake, and Flatland Lake. Watershed land-use revealed few specifics because of the scale of resolution (all mixed cover watersheds). Detection of specific pesticides indicated that urban and agricultural land uses both made substantial contributions to surface water contamination.
Comparison of automated versus manual monitoring of levels of dissolved oxygen in aquaculture ponds
Year: Authors: Fortune S., Tietjen T.
Automated water quality monitoring systems can be used to help maintain optimal levels of dissolved oxygen (DO) in aquaculture systems by continuously monitoring oxygen concentrations and immediately turning on aerators to supplement oxygen if a critical limit is reached. This study compares differences in water quality maintenance under operation schemes using manual and automated water quality monitoring of DO concentrations. A commercial automated monitoring system will be used to monitor the DO concentrations in the aquaculture ponds on the Mississippi State University campus. Data collected by this system will be used to document the amount of time that DO concentrations would have fallen below threshold levels under a manual monitoring operation scheme. Mississippi State University aquaculture facility employees will be interviewed to determine how often DO measurements are needed and how often they can be collected from the entire 75 pond complex. Data collected by the automated monitors will be used to simulate manual data collection by using the automated measurements and the sampling timeline for manual collection. Using this information will determine the amount of time that DO concentrations in the pond would have been below acceptable levels without automated monitoring. Automated monitoring systems should detect low DO concentrations more quickly than manual monitoring which will promote fish growth and facilitate the management and planning of aquaculture operations, and therefore increase overall production for catfish farms and other aquaculture industries across the country.
Determining Potential for Direct Recharge in the Mississippi River Valley Alluvial Aquifer Using Soil Core Analyses, Washington County, Northwestern M
Year: Authors: Rose C.E.
In 2005, the U.S. Geological Survey National Water-Quality Assessment program selected a site in the Bogue Phalia Basin for a study involving the sources, transport, and fate of agricultural chemicals. Because of its unique natural features, which include rich soils and an ample water supply, the basin is an ideal setting for agricultural activities, making it an area heavy in application of agricultural chemicals. In 2006, the U.S. Geological Survey began study at a site in Washington County, Mississippi. The objective of the study was to assess the potential for water and agricultural chemical transport to the Mississippi River alluvial aquifer by interaction with surface water and recharge from precipitation.<br><br> Previous water-quality and flow system studies of the Mississippi River alluvial aquifer in northwestern Mississippi, locally referred to as the "Delta", have given rise to the questions about the effect and magnitude of the vertical recharge component of the flow system. Some models have indicated that rainfall is the single largest contributor to recharge of the alluvial aquifer, which is a surprising result given the dense clay soils overlaying the aquifer. In the topostratum of an agricultural field adjacent to the Bogue Phalia near Leland, soil cores were collected during installation of four shallow wells (all less than 24 feet deep). The soil cores were analyzed for bulk density, grain size distribution, and permeability. Hydraulic conductivity was estimated using three methods: (1) a falling head permeameter to determine vertical hydraulic conductivity; (2) the Rosetta Stone program, which uses bulk density and grain size values to model hydraulic conductivity values; and (3) the Hazen method, which uses effective grain size and sorting of the soil to determine empirically the hydraulic conductivity. The resulting data indicate that the upper 8 feet of topostratum consists of a clay loam with vertical hydraulic conductivity values ranging from 10-5 to as low as 10-7 centimeters per second. The interval from 10 to about 16 feet was a sandy loam with hydraulic conductivity values ranging from 10-3 to 10-4 centimeters per second. The data and the relatively homogenous and continuous blanket of lower permeability clay loam suggest that the potential for vertical recharge is low. However, appreciable lateral recharge from the Bogue Phalia is likely as the river incises the clay loam to the higher conductivity fine, sandy loam interval.
Changes in water volume in the Mississippi River Valley Alluvial Aquifer in Northwest Mississippi
Year: Authors: Stiles M., Pennington D.
The Mississippi River Valley Alluvial (MRVA) aquifer in Northwest Mississippi is the primary source for agricultural crop irrigation in the Mississippi Delta. The water levels in the aquifer have generally declined in the past twenty years. Typically, the area in the center of the Delta experiences annual water level declines of approximately one foot. Several methods of analysis and display have been used to characterize these changes. These methods generally include the creation of hydrographs, contour maps, and two dimensional color grid maps of water level changes over a specified time interval. While these methods are useful for showing the areas of decline, the actual net gain or loss of water stored in the aquifer wasn’t able to be accurately calculated. Due to recent enhancements in water level surface determinations and updated historical water level measurements we can now calculate the approximate annual change in the volume of water in the MRVA aquifer. A water level surface grid is interpolated using the measurements taken for a given year then subtracted from the previous year’s surface. By using a one acre grid cell for both surfaces, the calculated difference value reflects the acre-feet of aquifer volume change for each grid cell. Then by adding all the change values for the entire one-year difference grid and applying a specific yield coefficient the change in water volume from one year to the next can be calculated. This annual change in water volume is very useful in understanding and protecting the Delta’s abundant supply of water.
Potential for infiltration through the fine-grained surficial deposits of the Bogue Phalia Watershed, Mississippi
Year: Authors: Mills P.C., Bryson J.R., Rose C.E., Coupe R.H.
The U.S. Geological Survey is conducting a preliminary assessment of the potential for deep infiltration of water and ground-water recharge through fine-grained Mississippi embayment deposits. Findings of this study will provide insight into the potential for transport of agricultural chemicals to ground water in this and similar humid regions of the United States. During an annular period that began in March 2006, various sediment-physical-property, sediment-hydraulic, ground-water, streamflow, and meteorologic data will be collected at two sites in the Bogue Phalia River watershed. The paired sites allow study of the somewhat varying sediment compositions distributed across the watershed. Relatively sandy soils planted with cotton compose the northern site near Gunnison; relatively sand-free soils planted with soybeans compose the southern site near Leland. Both sites are within 0.1 mile of the Bogue Phalia River. Within the study area, about 13 feet of predominantly silt sediments overlie at least 100 feet of sand deposits. The coarse sediments compose the Mississippi embayment alluvial aquifer, with ground-water levels generally about 15-30 feet below land surface. Instrumentation includes vertically nested piezometers and soil-moisture sensors, as well as a meteorologic station, deep ground-water well, and streamgage. Much of the instrumentation is monitored continuously with data-logging devices and the data served to the World Wide Web.<br><br> Preliminary data from the growing season of March-September 2006, indicate infiltration generally is limited to the uppermost 3-4 feet of the soil horizon, or just below the primary root zone of the planted crops. Following rainfall events, no appreciable increase in soil-moisture content was detected at monitored depths approaching 9 feet. Underlying ground-water levels and stream stage responded almost instantaneously to these events, indicating that the aquifer and nearby river are in direct hydraulic connection with ground-water levels affected by stream stage. The fine composition of the surficial sediments (generally containing less than 25 percent fine sand) and their presumably low vertical hydraulic conductivity appear to inhibit the deep infiltration of water. Presently, available data are not adequate to differentiate between the deep-infiltration characteristics of the varying sediment compositions that distinguish the two study sites. Additionally, the reported growing season was unusually dry, with 25 to 50 percent of normal seasonal rainfall (about 18 inches recorded). Infiltration response during a seasonally wet period, when evapotranspiration rates are correspondingly low, will need to be monitored to more fully assess the potential for deep infiltration through of these fine-grained sediments.
Mississippi River Valley Alluvial Aquifer Geology of the Central Delta (East Central Sunflower County and West Central Leflore County)
Year: Authors: Bryd C.B.
The Mississippi River valley alluvial aquifer (MRVA) underlies the alluvial plain in northwestern Mississippi, an area commonly known as the Delta. This very prolific aquifer is the most intensely developed source of groundwater in Mississippi, and is used mostly for irrigation and catfish culture. Probably one of the most intensely developed areas within the Delta is East Central Sunflower County and West Central Leflore County where most of the alluvial wells are used for rice and catfish. As a result of the intense use of groundwater from the MRVA in this area, water levels have declined more rapidly than water levels from the surrounding Delta area. <br><br> Considering the tremendous importance of this aquifer to the economic viability of agriculture in the Delta, understanding the geology of the MRVA, along with water level trends, is imperative for proper planning and management of this water resource. <br><br> Since the fall of 1980, water levels from wells screened in the alluvial aquifer Delta-wide have been collected twice each year. The number of wells in this project, called the semi-annual survey, has varied from approximately 300 to currently over 500. Staff of the MDEQ’s Office of Land and Water Resources has been involved in an ongoing drilling project to determine the remaining amount of saturated thickness within the alluvial aquifer. Stratigraphic holes have been drilled near several of these wells to determine the geology, including the depth of the base of the MRVA, the thickness of the surficial clay, the physical characteristics of the saturated portion of the aquifer, as well as whether or not the MRVA is connected to an underlying aquifer. <br><br> Future drilling sites include southeast Bolivar County, north Sunflower County, and west Leflore County adjacent to the Tallahatchie River.
Mississippi River Floodplain "Delta" - Bluff Margin Alluvial Fax Complexes
Year: Authors: Starnes J.E., Marble J.C.
Lateral migration of the Mississippi River into the river’s east valley wall creates an escarpment of Peorian loess (often thick), Early Pleistocene Pre-loess terrace deposits (coarse sand and gravels of the ancestral Mississippi River), and underlying Tertiary formations (which commonly form the toe of the escarpment). As the river migrates westward from the escarpment, the trunks of dendritic drainage systems must cross an alluvial plain of low relief. Alluvial fans develop where the stream trunk enters into the "Delta" as these streams lose their energy and therefore their bed load. These fans owe their size to the extensiveness of their watersheds and are fed by an unconsolidated sedimentary section with a high susceptibility to erosion and where mass wasting events such as failures in the loess are commonplace. The streams receive spring water in their upper reaches from a loess/terrace and Tertiary bedrock where the lithologies permit. The trunk of the stream recharges the alluvial fan (or fan complexes where neighboring fans inter-finger) and possibly even the Mississippi River alluvial aquifer where the alluvial fan and the river alluvium inter-finger. Unlike much of the Mississippi River alluvium the "Delta"-bluff margin alluvial fans may receive recharge from surface waters over parts of the fan. The thickest accumulation of coarse-grained sediments is near the apex of the fan and this may be a local source of groundwater for agricultural irrigation or domestic wells. The fans are elevated above the flood plain surface and are associated with running water, and therefore, they commonly contain large, well-preserved, often multi-component, archaeological deposits.
Conservation planning for fish assemblages based on land cover distribution
Year: Authors: Schweizer P.E., Matlack G.R.
Landscape dynamics over various spatial scales are integrated by fish assemblage composition. We examined species diversity and abundance pattern of fish assemblages from 27 selected headwater or low-order outer coastal plain streams near Hattiesburg, Mississippi. Non-metric multidimensional scaling (NMDS) identified measures of fish assemblage composition which best described assemblage differences based on richness, diversity and species dominance. Assemblages varied in composition by feeding preference, water column position of dominant species, and tolerance to increased water temperature and silt or sediment deposition. Observed assemblage compositions are likely the result of synergistic processes with nested relationships between landscape structure, land cover, and spatial distribution of land cover. Mosquito fish and sunfishes were the most abundant species in urbanized catchments while minnows, darters, and madtoms contributed to larger species diversity in rural and forested watersheds. Rural and forested catchments with stable land cover exhibited the largest fish species diversity. Results of this study contribute to our understanding of how spatial distribution of land cover influences watershed health as measured by water quality, stream geomorphology, and fish assemblages as biotic indicators of watershed condition, and identified sensitive areas and land cover with potential negative impacts on biotic diversity for consideration of conservation planning.
Real-Time Pier Scour Monitoring on the Pascagoula River at Interstate 10
Year: Authors: Storm J.
Scour at bridge piers located within a stream channel or floodplain is a major cause of bridge failure. Erodable sediment can be degraded away from a bridge pier during a flood to the point where the pier is undermined and failure is imminent. Laboratory models and field analyses have been used to quantify the components of scour. The three basic components include: <ol><li> Local scour: erosion caused by local disturbances in the flow. This can be caused by build-up of debris on the pier, or the vortices that naturally are produced by the pier.</li> <li>Contraction scour: erosion caused by the increased flow velocities as the approach flow is forced through the reduced area of the bridge opening.</li> <li>General scour: erosion that naturally occurs in a channel even when there is no bridge present.</li></ol> The U.S. Geological Survey, in cooperation with the Mississippi Department of Transportation, has installed a real-time scour monitoring gage at a pier bent on the east-bound bridge at the U.S. Interstate 10 crossing of the Pascagoula River. The gage records both stream stage and channel-bed elevation at 15-minute intervals. The channel-bed is monitored using in-situ transducers at the upstream and downstream sides of the pier bent. Data are transmitted hourly via the Geostationary Operational Environmental Satellite, stored in a local database, and made available to the public at the following web site: <a href="http://ms.water.usgs.gov" target="blank">http://ms.water.usgs.gov</a>. The objective of this gage is to monitor scour effects over time on a near instantaneous interval at a bridge pier that has been subjected to past scour problems, resulting in the loss of as much as 20 feet of penetration since the bridge was completed in 1975.
Agricultural water use in the Mississippi Delta
Year: Authors: Powers S.
Agricultural water use from the Mississippi River Valley Alluvial Aquifer exceeds long term recharge rates and is resulting in declines of aquifer water levels. Understanding agricultural water use is essential to developing plans to reduce groundwater use to match the long term recharge of the aquifer. This paper reports the amount of ground water pumped on to the major crop types and the irrigation methods of the Mississippi Delta. Water use numbers have been gathered by YMD staff over the past 15 years in an effort to determine annual water use per acre. Major crop types studied include: Cotton, corn, soybeans, rice and catfish. Water used on individual sites is determined by obtaining flow rates for each well in the study, then determining each well’s time of operation. By multiplying the flow rate by the time the wells ran, the amount of water pumped can be obtained. Field size is determined through the use of aerial photos and site inspection. The total water pumped is then divided by the acres receiving water to get water used per acre. Irrigation methods are recorded for each site. Different irrigation methods observed include pivot, furrow, contour levee, straight levee, straight levee multiple inlets, and zero grade. The per acre water use numbers are shown in three different ways: 1.) Annual water use across all crop types, 2.) Average water use per acre for each crop type, 3) Where it is relevant, water use per crop type by different irrigation methods. In 2006 results showed cotton use an average of .84 acre feet per acre over the course of the growing season. Soybeans used an average of 1.00 acre feet per acre, corn used an average of 1.16 acre feet per acre, catfish used an average of 2.40 acre feet per acre, and rice used an average of 3.34 acre feet per acre. These numbers represent the highest amount water used since 2000.
Evaluation of HSPF Streamflow Uncertainty Bounds Due to Potential Evapotranspiration Bias and Parameter Variability
Year: Authors: Diaz J.N., McAnally W.H., Martin J.L.
The Hydrologic Simulation Program - FORTRAN (HSPF) is used to develop Total Maximum Daily Loads (TMDLs). Watershed models are defined by input time series (e.g., precipitation, evaporation, etc), physical characteristics of the area (e.g., size, slope, land use, etc), and algorithms. Approximations of real environments using models are a good alternative to reduce costs and save time; however modelers are faced with various uncertainties in input and output data, model parameters, and model structure due to lack of knowledge and/or random variability of the processes. Quantification of uncertainty should be considered in TMDL models. Probabilistic point estimation methods propagate the parameter uncertainty by performing point estimations of the parameter space instead of calculating the entire probability density function (PDF). The objective of this study is to evaluate potential evapotranspiration and parameter uncertainty propagation on simulated flows using the Harr’s probabilistic point estimate method. This work attempts to model daily flows using the HSPF model and uncertainty bounds for a watershed in Alabama and Mississippi. Uncertainty bounds for daily streamflows are generated using the 5th and 95th percentiles of simulated flows. Twelve HSPF parameters and +/- 5%, +/-10%, +/-20%, +/-30%, +/-40% and +/-50% of potential evapotranspiration data are evaluated. Observed daily streamflow data from 01/01/2001 to 11/30/2004 are used to evaluate the HSPF uncertainty bounds. From the bounds constructed using parameter uncertainty for the evaluated period, the observed streamflow data are 77% within the 90% certainty bounds. The model is more sensitive to lower potential evapotranspiration linear bias than higher values.
Spatial distribution of land cover and their influences on watershed condition
Year: Authors: Schweizer P.E., Matlack G.R.
Using competing spatial models we examined the influence of spatial distribution of land cover on watershed condition for headwater and small-order streams in Forrest and Lamar County, MS. Land cover analysis utilized multi-spectral aerial photography, Landsat5 data, National Agriculture Imagery Program (NAIP) images, and GIS to evaluate contribution of spatial extent and position of land cover type within catchments on water quality, stream geomorphology and fish assemblages. Land cover distribution varied between watersheds. Land cover analysis identified forest vegetation as dominant element within the landscape matrix. Total variation in water quality was greater among catchments with different land cover type than within catchments with similar land cover. At the catchment scale the spatial extent of total forest cover was the best predictor of watershed condition. Impervious surfaces, transient land cover, and managed green areas were correlated to stream hydrology, creek bed geomorphology and sediment transport, with impervious surface cover and managed green areas as strongest influences on stream conditions at the reach scale. Fish assemblages varied in their composition. Urbanized catchments showed pauperized species diversity with an increase in cosmopolitan species compared to watersheds with a dominant rural or forest land cover. Results of the study indicate that not only the spatial extent of land cover type but also their explicit spatial distribution within the catchment influence watershed condition.
Pesticide Runoff from Bermudagrass: Effects of Plot Size and Mowing Height
Year: Authors: Ampim P.A., Massey J.H., Stewart B.R., Smith M.C., Armbrust K.L., Johnson A.B., Andrews A.
Improved prediction of environmental concentrations of pesticides in the urban environment involves understanding factors that affect their transport. We investigated the effects of plot size and mowing height on pesticide runoff from Mississippi Pride bermudagrass (Cynodon dactylon [L] Pers. x Cynodon transvalensis Burtt-Davy) maintained as golf course fairways and residential lawns. The fairway and homelawn treatments were cut at 1.3 cm and 5 cm respectively. The study was conducted on a hydrologic class D Brooksville silty clay soil (fine montmorillonitic, thermic Aquic Chromudert). The four plot sizes investigated were 1.8 x 1.8 m, 3.7 x 9.1 m, 6.1 x 24.4 m and 12.2 x 38.1 m. The plots had 3 % slope with minimal cross slope. The experimental design was a randomized complete block design with split plot arrangement of treatments. The main plot factor was plot size while the sub-plot factor was mowing height (1.3 and 5.0 cm). Following a standardized protocol, the dimethylamine salt of 2, 4-D herbicide, flutolanil fungicide and chlorpyrifos insecticide were co-applied at 1.12 kg ai/ha, 2.24 kg ai/ha and 2.24 kg ai/ha, respectively. A conservative tracer (KBr) was also applied separately at 15 kg/ha to allow tracking of water movement in the turfgrass system. Simulated rainfall was applied at 38.1 mm/h to the plots 24 h after pesticide application. Pesticide concentrations in runoff and application monitors were analyzed by a high performance liquid chromatography using UV-Vis detection. The limit of quantification for the three pesticides was approximately 10 ppb. Plot size and grass mowing height effects on pesticide runoff and several hydrological parameters will be discussed.
Modeling Mobile Bay Sediments and Pollutants with New Technologies
Year: Authors: McAnally W.H., Martin J.L., Tagert M.L., Sharp J.
The overall goal of this new investigation is to provide insight into the flow of sediment and specific associated pollutants in the Mobile Basin and similar coastal basins so that resource management decisions can be made in an informed manner and the Basin’s environmental quality improved.<br><br> The work will develop a management-oriented model of sediment, mercury, and dichlorodiphenyltrichloroethane (DDT) for Mobile Bay and the major tributaries to the Bay. The study will first synthesize available data in order to obtain mass budget estimates for water and sediments. Numerical models previously applied to the system will be refocused, and/or converted, to simulation of sediment, DDT and mercury. The models, along with available data and data analysis tools, will be used in the assessment of factors impacting the fate and transport of mercury and DDT in the Basin. Estimates will be made, wherever possible, as to the uncertainty of assessments based upon data and/or model results. Estimating uncertainties is of particular importance since, for example, some of the processes impacting the transformations of mercury, such as methylation, are poorly understood and quantified. The available data and model predictions will be used to evaluate potential management strategies (e.g. no action and action alternatives) using a weight of evidence approach. The modeling and data analysis tools will also provide a basis for a "living model" of the Basin that can be updated to address other management questions as they arise. Work to date has consisted of compiling and analyzing data from Mobile Bay and set-up of transport models.
Integration of Impact Factors of Gas-Liquid Transfer Rate
Year: Authors: Duan Z., Martin J.L.
The gas transfer rate at air-water interface (reaeration rate) has significant impact on surface water quality. The gas transfer rate is affected by multiple factors including stream, wind, wave breaking, etc. When wind is blowing over water, the turbulence generated at the air-water interface is the predominant factor impacting reaeration. A number of empirical relationships have been established for the gas transfer rate as a function of wind speed (Broecker 1978; Jahne 1979; Liss and Merlivat 1986; Wanninkhof 1992; Wanninkhof and McGillis 1999). A theoretical model of the wind reaeration rate has also been developed by O’Connor (1983). However, in addition to wind-induced turbulence in an "unbroken" water surface, wave breaking is predominant factor impacting reaeration in the "broken" water surface, where the reaeration is driven by the bubble-mediated gas transfer. In this paper, a relationship is developed to integrate the effects of wave breaking and wind on the rate of reaeration.
Effects of Agriculture on Ground Water in a Recharge Area of Guarany Aquifer in Brazil
Year: Authors: Cerdeira A.L., Pessoa M.C., Bolonhezi D., Gomes M.A., Spadotto C.A., DeSouza M.D., Ferracini V.L., Queiroz R.H.
The region of Ribeirao Preto City located in Sao Paulo State, southeastern Brazil, is an important and highly mechanized sugar cane producing area. It is also an important recharge area of the Guarany aquifer, which provides water to several cities and rural communities in the region. Research has been conducted in this region since 1995 to assess the behavior of herbicides, such as atrazine, simazine, ametryn, tebuthiuron, diuron, 2,4-D, picloram, and hexazinone, applied in the area. Nitrate applied as nitrogen fertilizer was also evaluated. Espraiado watershed, located over the recharge area, was chosen for this study. Water samples were collected from seven wells located inside the watershed and from surface water of Espraiado stream. Other samples were taken from city wells located at the edge of the recharge area with exception of the control samples that were collected from downtown wells. Results have shown that no residue of herbicide was found in ground water wells and only ametryn was found at levels higher than the Maximum Concentration Level (MCL) of 0.1 ug/L in surface water of the watershed. However, nitrate was detected at levels close to the MCL of 10 mg/L in wells located in downtown, far away from the sugar cane area.
Irrigation Water Conservation Through Use of Level Basins in Louisiana
Year: Authors: Branch B., Daniels G.
Irrigation is standard practice for rice production in Louisiana. It is increasingly used to provide yield enhancement and insurance against periods of inadequate rainfall for cotton, corn and soybeans, even though drainage is the primary water management issue for crop production. Most irrigation pumps in Louisiana are powered by diesel engines and producer interest in improving irrigation efficiency is increasing as energy prices increase.<br><br> Land owners in many Southern states have been grading fields to low (<0.2%) slope to improve drainage and increase machine and irrigation water use efficiency. Some land owners are grading fields to zero slope (level-basin) for use in growing rice. <br><br> Measurement by the YMD Joint Water Management District, Stoneville, MS, (Epting, 2003-2004, Powers 2005-2006) of water used in irrigating rice indicates significant water savings on level basin fields compared to other rice field irrigation designs. Louisiana growers have also successfully used level-basin rice fields for crawfish production and for duck hunting. Growers would like the option of growing cotton, corn or soybeans on level-basin fields when market prices, input costs or weed conditions support these crops in preference to rice. <br><br> Cotton growers in Arizona have used level basins and have achieved high irrigation water use efficiencies. (Clemmens, 2000)<br><br> One of the advantages of level basins for rice, crawfish or ducks is the low flow rate pump capacity required to manage the system. Flood irrigation of cotton, corn or soybeans requires getting the water on the field and draining it quickly to avoid damage to the crop. Low pump capacity requires more time to irrigate, thus possibly leaving the root zone saturated too long and reducing yields of these crops.
Sediment Monitoring of Mill Creek, Rankin County, Mississippi
Year: Authors: Runner M.S.
Mill Creek in Rankin County, Mississippi, drains an 11 square mile watershed and flows into Pelahatchie Bay of the Ross Barnett Reservoir. Higher than expected sediment yields from Mill Creek have required that dredging operations in the affected areas be completed on 3-year intervals rather than the 10-year intervals which were planned when the reservoir was constructed. <br><br> A study of sediment yields during four storms in 1998 indicated that some areas of the watershed had significantly higher yields than other areas of similar size. In 2006, the U.S. Geological Survey, in cooperation with the Rankin County Board of Supervisors, began collecting streamflow and sediment concentration data at three locations in the watershed. The data are being collected to monitor the effects of structural improvements installed by Rankin County to reduce the volume of sediment flowing from Mill Creek into Pelahatchie Bay. Two locations were sampled as part of the 1998 study, allowing a comparison of the discharge-sediment concentration relation for the two time periods. The third sampling location will provide information on the sediment concentrations in the runoff from a primarily undeveloped area.
Pre-settlement sediment accumulation rates in lake-wetland systems in the Mississippi Delta region using the 14C activity of bulk sediment fractions
Year: Authors: Davidson G.R., Walker W.G., Lange T., Wren D.
Sediment accumulation rates in lakes and wetlands are known to increase when neighboring land is converted to agricultural use, but the magnitude of historical changes is often difficult to assess. In most areas, few records exist on the natural rate before large-scale changes in land use began. This is particularly true in areas such as the heavily cultivated Delta region of Mississippi where most of the land was cleared more than a century ago. Standard methods such as 137Cs and 210Pb dating techniques are useful for establishing modern sediment accumulation rates in these areas, but not for establishing rates prior to settlement.<br><br> Carbon-14 has often been used in lake studies to determine the age of specific layers or to determine ancient sedimentation rates, but methods generally rely on isolating recognizable plant fragments or fossils that are often difficult to find. Where macrofossils are absent, pollen may be dated, but extraction of pollen is labor intensive and requires use of toxic chemicals. Bulk sediment fractions are not generally preferred because they contain an unknown mixture of organic material of variable age, they may contain dead carbon such as lignite that is difficult to eliminate, and material of aquatic origin may be subject to reservoir effects that add apparent age. If the various processes that contribute carbon to the system are relatively constant over time, however, changes in 14C activity with depth may be used to accurately estimate sediment accumulation rates even if the absolute age are erroneous. <br><br> In this study, fine-grained fractions (250-710 um organic material, humic acid extract from <250 um size fraction, and untreated <250 um size fraction combusted at low temperature) were analyzed and compared with terrestrial plant stems (twigs), charcoal and wood fragments in sediments from Sky Lake in Humphreys County, Mississippi. The 14C activities of the bulk fractions were highly linear with depth, and produced consistent calculated sediment accumulation rates similar to, and perhaps more reliable than rates determined using twigs or charcoal.
Effects of sitation on some aquatic animals communities in a man-made lake in Ilorin, Nigeria
Year: Authors: Nzeh C.G., Bello I.
The effects of siltation on aquatic animals communities in a man-made lake in Ilorin, Nigeria were invertigated. Samples of the sediments were collected using Ekman’s grab. The sediments were sieved through various mesh sizes until fine silt were obtained. The silt were air-dried to a constant weight in the laboratory and measurement of the final weight of the silt were taken. Macro-invertebrates were collected using scoop nets and identified. The fishes were collected using cast and gill nets. The water temperature, pH, dissolved oxygen content and transparency were measured. Results indicate that the surface water temperature ranged from 23 to 270C. Dissolved oxygen content of the lake varied from 3.6 to 4.4 mg O2/l. The water transparency fluntuated between 88.75cm to 153cm while the silt content of the lake was 11.27% to 24.6%. The invertebrates collected were gastropods and bivalves. The fishes in the lake were family Cichlidae which was the most abundant, other families were Bagridae and Anabantidae. Silt was gradually being deposited in the lake and the volume of water in the lake was gradually being reduced especially during the dry season when there is little or no rainfall. Some portions of the lake dried up during the dry season due to accumulation of silt and the invertebrates living in the affected area of the lake were exposed to dessication resulting in decrease in population of invertebrates. This fresh water lake is gradually being degraded and factors such as construction of residential houses around the lake and agricultural practices were identified as the major causes of siltation of the lake.
Experimental design analysis applied to factors related to migration of sediment out of a stormwater catchbasin sump
Year: Authors: Avila H., Pitt R.
The sediment-capture performance in conventional catchbasin sumps has been reported to be in the wide range between 14 and 99% (USEPA, Metcalf & Eddy 1977); obviously, the higher performance is obtained by combining low flowrates, large particle sizes, and high specific gravities. Typically, up to about 30% of the total stormwater particulates are captured during actual rainfall tests (Pitt 1985). The accumulation rate, or sediment-retaining performance, depends on the size and geometry of the device, the flow rate, sediment size, and specific gravity of the sediment. In the same way, scour phenomenon includes all those parameters previously mentioned, in addition to the water protection layer and the consolidation of the sediment bed due to aging.<br><br> In order to evaluate the importance of the parameters and their interactions on the phenomenon of scour of sediment out of a conventional inlet catchbasin, a modeling experiment was designed (24 full-factorial) and performed examining four parameters (flow rate, sediment size, water protection depth, and specific gravity). Each factor was evaluated at 2 levels: flow rates at 1.6 L/s and 20.8 L/s, sediment diameters at 50 um and 500 um, water protection depths at 0.2 m and 1.0 m over the sediment, and sediment specific gravities at 1.5 and 2.5. A 2-dimensional Computational Fluid Dynamic (CFD) model was implemented in Fluent 6.2, using the Eulerian multiphase model. The evaluation consisted of determining the reduction of sediment mass from the chamber over time. When examining the loss of sediment after 1,000 sec of continuous flow (17 min), the results showed that the expected important parameters of flow rate, sediment size, and water protection depth, were statistically significant when explaining sediment scour. The water protection depth over the sediment is related to the extent of exposure of the sediment layer to the in-flowing water. However, it was also found that specific gravity of the sediment was not an important factor affecting sediment scour.
Water Quality Impacts of Failing Septic Systems in a Coastal Area
Year: Authors: Tagert M.L., White Q., Martin J., Pote J.
A study is underway to determine the water quality impacts of failing onsite wastewater systems (OWS) on the St. John’s River and its tributaries near Jacksonville, Florida. The four main objectives of the study are as follows: 1) review previous Total Maximum Daily Load (TMDL) studies and other studies related to failing OWS in the study area, 2) compile and review data on permits issued for OWS, 3) incorporate geospatial technologies to help develop a water quality sampling plan and analyze potential trends, and 4) implement an intensive sampling plan to analyze samples at 3 baseline sites and approximately 8-14 potentially impacted sites for total Kieldahl nitrogen (TKN) and phosphorous. Field measurements for temperature, salinity, and dissolved oxygen are also being taken at each sampling site. Efforts are being made to capture both dry and wet weather samples monthly at each site from September 2006 through February 2007, or for the duration of the project. Sample collection and analysis has begun, although a lack of rainfall has limited sampling to date. Collection of ground truth information and water samples has been initiated. Sampling results will be evaluated as data becomes available throughout the initial six-month project and will be included in this presentation. An analysis of the data will determine if the project should be extended for an additional six months or more.
Occurrence and Persistence of Pesticides, Pharmaceutical Compounds, and other Organic Contaminants in a Conventional Drinking-Water Treatment Plant
Year: Authors: Coupe R.H., Bach D.P.
In late August and early September 2006, the U.S. Geological Survey, with assistance from the City of Jackson, collected three sets of water samples from the Ross Barnett Reservoir and O.B. Curtis drinking-water treatment plant. Each set included a sample of (1) the source water from the reservoir; (2) effluent from the settling process (but before dual media filtration and chlorination); (3) and the finished water. Each sample was analyzed for over 100 compounds including pesticides and pesticide degradates, pharmaceutical compounds and other organic contaminants that are indicative of wastewaters. Four herbicides (atrazine, metolachlor, hexazinone, and floridone) and 2 pesticide degradates (deethyl-atrazine and desulfinyl fipronil), and caffeine and cotinine (a nicotine degradate) were detected in low concentrations in 1 or more source water samples. These compounds were detected in the settled and finished water in roughly the same concentrations as detected in the source water. The concentrations were all below 0.5 ug/L, which is several orders of magnitude below acute toxicity levels as determined by the U.S. Environmental Protection Agency for pesticides and pesticide degradates. Atrazine and metolachlor are used for the protection of crops in the production of food and fiber, but also are used in urban areas to control weeds in lawns, parks, and other recreational areas. Hexazinone is used in silvilculture, and floridone is used in the upper parts of the Ross Barnett Reservoir to control aquatic vegetation. Caffeine and cotinine are likely derived from sewage-treatment-plant effluent discharged into streams that supply the Ross Barnett Reservoir. Most compounds were not detected in any samples, and a few compounds were present in the source water but not in finished water; thus, indicating that these compounds are either degraded or removed by treatment processes used at this facility.
Mississippi Watershed Characterization and Ranking Tool (MWCRT)
Year: Authors: Storelli J.
The Mississippi Watershed Characterization and Ranking Tool (MWCRT) is an easy to use spatial tool of broad applicability. The MWCRT uses geographic information systems (GIS) to assess readily available statewide spatial datasets within the watersheds of major river basins. The watersheds are based on the 12 digit hydrologic unit code dataset created by the United States Geological Survey (USGS). The tool helps users determine which watersheds are of higher value based on the presence of important natural resource features. These features are described by land uses and surface water uses within the watersheds of a major river basin. Each spatial layer is placed into a broad category to determine its resource value on the environment, its impact on human welfare and to assess the stressors placed on each watershed. Each category can be used to describe or characterize the natural resource datasets within the watersheds of the major river basins. This information is used to generate a ranking system that determines scores for each watershed. The ranking system is generated based on the raw spatial data expressed as observations for point data, miles for line data and acres for polygonal datasets. These raw data values for each dataset are normalized using a linear scaling transform equation and assigned weights by relative importance. The final output provides a value for each watershed. Each watershed can be ranked by individual dataset or by combining datasets to produce a ranking system by category. The MWCRT provides a way to identify watersheds of interest, make meaningful decisions and to prioritize watersheds for protection and restoration activities. The purpose of MWCRT is to provide the Mississippi Department of Environmental Quality (MDEQ) and its state and federal agency partners with a tool to help manage the state’s water resources.
Biological Remediation of Oriented Strand Board (OSB) Waste Water
Year: Authors: Strombock L.B., Diehl S.V., Borazjani H., Baldwin B.S., Prewitt M.L.
Oriented strand board (OSB) is a wood composite product made from wood strands heat bonded with resin adhesives and waxes. In 2001, 22 billion square feet of OSB was produced in the US. The OSB manufacturing process generates large amounts of wastes including wood, water, resins, waxes and organic compounds such as terpenes, resin acids, phenol formaldehyde resins, and other wood leachates. High levels of organic materials as measured by its biological oxygen demand (BOD) determines whether this water is suitable for discharge. High BOD levels correlates to a high organic matter content and low oxygen availability. The wastewater used in these studies was collected from an OSB manufacturing plant and contained an initial BOD concentration of 1600mg/L. The first study evaluated free cell bioreactors to reduce the BOD concentration in this process waste water using four treatments with three replications within each treatment. Treatment one was the control treatment; treatment two added aeration; treatment three consisted of aeration plus an indigenous microbial consortium; treatment four consisted of aeration, an indigenous microbial consortium, plus a nitrogen-phosphorus based fertilizer. BOD levels were determined on day 0 and every 15 days until day 105. Toxicity was determined on day 0 and day 105. Results revealed after 30 days, a 57% BOD reduction in treatment 1, 72% and 73% reduction in treatment 2 and 3 respectively and 84% reduction in treatment 4. By day 105, all treatments showed a 93% BOD reduction and treatment 2 showed the greatest toxicity reduction. The second study was to determine if plants could reduce BOD levels in OSB process waste water. Water hyacinth, Chinese water chestnut, Azolla, Small duckweed, Bullrush, Beak-rush, soft rush, Bald cypress and Black Willow were screened for survival in high BOD process waste water. Chinese water chestnut, Small duckweed, soft rush and water hyacinth survived the initial screening study and were further evaluated. Two clumps of each plant type were placed in fiberglass tubs containing OSB process waste water or natural lake water. Treatment one consisted of floating plants and treatment two consisted of emergent plants. After 75 days the BOD levels were reduced by 84% in the floating plants compare to 96% in the emergent plants.
Presenting Nutrient Data Online Using a Customized ArcIMS® Map Viewer
Year: Authors: Perry H., Trigg C., Anderson J., Mallette F., Criss G.A., Viskup B.
The ability to easily share geographical and associated environmental data among researchers, managers, planners, and the concerned public is an important and powerful tool. Data on water quality was collected during 2003-2004 by the Center for Fisheries Research & Development, The University of Southern Mississippi, as part of a larger series of studies to establish numerical criteria for nutrients in the State’s coastal waters. The water quality study was made accessible using an interactive online Geographic Information System. The first step in the creation of the web site was the development of a custom ArcIMS® DHTML viewer. The ArcIMS DHTML viewer is a collection of HTML and JavaScript files that dynamically generate map images of a specified Map Service based upon user interaction. The custom viewer maintains the uniform appearance of web pages in the web site and its more efficient page layout provides more area for map images. The custom viewer becomes a template to generate all subsequent web sites, allowing rapid deployment of new Map Services. (A Map Service is a process that runs on one or more ArcIMS® Spatial Servers.) Map Services are based on instructions written in ArcXML that specify the data sources to be used in the map and how to symbolize the different data layers.
Precise Elevation Modeling for Hydrologic Decision Support System in the Cabuçu de Baixo Urban Basin in Sao Paulo City-Brazil
Year: Authors: Nobrega R.A., Leme de Barros M.T., Quintanilha J.A., O'Hara C.G.
The Sao Paulo Metropolitan Region is composed by 35 municipalities, with a population estimated in 17 million people. The post-70’s intense urbanization of the area has caused many hydrologic problems. Flood frequency has increased, as well as peak flows during the rainy season. Some hydraulic improvements have aimed to reduce the damages, however with limited success. The lack of integration decision-making can be considered as one of the most important causes of the increases in urban flooding. However, from a technical point of view, the lack of precise information maybe can be considered the most important factor vitally needed for delivering desired engineering solutions. Regarding the hydrological investigation, urban basins are more affected by land cover changes than their rural counterparts. The Cabuçu de Baixo watershed is a typical Sao Paulo City area, characterized by recent and unplanned occupation. Dense urbanization can be found intermixed with some parts of preserved nature located in the upstream part of the basin. During the last three decades, its land cover was abruptly changed. Irregular and unplanned settlements were formed over hills and valleys, replacing the vegetation. Later, the number of buildings increased. Implementation of transportation, electrical and hydrological utilities have been required. Sometimes, many of these implementations were done without the use of actualized maps. Due the characteristics of these areas, the use of recent technologies like LIDAR or IFSAR could produce faster results for the geo-database actualization. However, regarding the difficulties for developing countries, the absence of maps, or the amount of obsolete data, has resulted in the adoption of alternative methodologies, aimed at faster and less onerous paths without the needed commitment to a quality solution. Simulating surface water and flooding based on current geo-technologies is an efficient tool for planning and management for urban environments. In accordance with the principle that "the more actualized the reference database, the more accurate the investigation" this paper illustrates in a real-world example the necessity of precise geoinformation for urban basin investigation. A methodology of terrain modeling for hydrological studies based on breaklines extraction is reported. The coarse detailing was used for the mountainous regions and the finer one for other areas. The meadow areas were prioritized for precise simulation of flooding. Very high resolution orthophoto and contour maps were generated and applied to the Hydrologic Decision Support System. The final analysis shows the viability of the methodology for studies of urban hydrology.
Channel planform stability and instability in the Pascagoula River and Tributaries, Mississippi
Year: Authors: Mossa J., Coley D.
Because the Pascagoula River and its tributaries traverse a number of geologic units and the basin shows a diverse set of land cover and land uses, it is not surprising that different reaches in the basin show varying degrees of stability. To better understand this, planform changes were mapped for the Leaf, Chickasawhay, Pascagoula, and some of their major tributaries in a GIS using varied sources of data (aerial photographs, topographic maps and digital ortho quarter quadrangles). Unstable reaches have varied forms, including reaches with cutoffs, reaches with avulsions, reaches with direct anthropogenic channel alterations, reaches with appreciable lateral migration, and reaches that have altered in width. Using channel boundary data that was created in the GIS, this paper discusses the types and spatial patterns of varying degrees of stability/instability in the system. Polygon areas derived from overlays characterizing changes (areas of erosion, deposition, no change, and areas between channels) in channel position and planform were extracted from the GIS and normalized for scale, so that larger rivers could be compared with the headwaters, as well as smaller rivers and creeks. This study provides insights into the natural factors and anthropogenic activities that influence channel changes in this basin, and thus where future change might be expected to occur. Those insights, in turn, can be applied to management and engineering in the basin.
Effects of Hurricane Katrina on the Fish Fauna of the Pascagoula River Drainage
Year: Authors: Schaefer J., Mickle P., Spaeth J., Kreiser B.R., Adams S.B., Matamoros W., Zuber B., Vigueira P.
Large tropical storms can have dramatic effects on coastal, estuarine and terrestrial ecosystems. However, it is not as well understood how these types of disturbances might impact freshwater communities further inland. Storm surges can change critical water quality parameters for kilometers upstream, potentially causing subtle shifts in community structure or more drastic fish kills. Hurricane Katrina was one of the largest such storms to strike the coast of Mississippi and provides an opportunity to examine these effects in areas where we had pre-storm fish community data. In the weeks following the storm, fish kills were reported from some of the lower portions of the drainage. As part of a separate ongoing research project, monthly electrofishing surveys were conducted in 2004 and 2005 at ten sites throughout the Pascagoula River drainage. Survey effort was evenly divided among bank, sandbar and open channel habitats at each site from June through November. Sites ranged from 90 to 250 river km from the mouth of the Pascagoula River, creating a gradient of storm impact with which to judge storm effects on big river fish fauna. In addition, we compare pre- and post-storm communities along Black Creek, a medium-sized tributary, as well as in a group of small, headwater tributaries.
Short Term Impacts of Hurricane Katrina on the Dissolved Oxygen Content of the Lower Leaf River Water in South Mississippi
Year: Authors: Howell F.G., Smith A., Wally B.
One of the impacts of Hurricane Katrina on the quality of surface water in rivers and streams of the affected area was a serious depletion of dissolved oxygen content. Personnel at the Koch Cellulose pulp mill in New Augusta became aware of the problem shortly before they were to resume effluent discharge to the Leaf River; consequential contact with the Mississippi Department of Environmental Quality in Jackson dictated that dissolved oxygen concentrations in the receiving water (Leaf River) must be at least 5 ppm before such release could occur. Therefore, a monitoring effort was done at strategic points upstream and downstream of the mill’s effluent outfall to monitor the dissolved content of the river water. Initial sampling was began on 7 September and terminated on 11 September. Dissolved oxygen readings ranged from 2.35 to 3.2 ppm for all sampling locations sampled on the September 7. Monitoring data were collected at three to four hours intervals until it was obvious that the sustained dissolved oxygen readings were well into the fives. The monitoring effort was terminated late afternoon September 11.
Use of Heat Tracing to Quantify Stream/Groundwater Exchanges During and After Hurricanes Katrina and Rita in the Bogue Phalia, Northwestern, Mississi
Year: Authors: Bryson J.R., Coupe R.H.
Heat provides a natural tracer of groundwater movement, which is readily tracked by measuring changes in streambed sediment temperature. Heat tracing has been used successfully in a number of studies to determine whether a stream segment is gaining or losing water. When water is moving into or out of the bed sediments it carries with it a measurable amount of heat, creating different temperature profiles in the bed sediments depending upon whether ground water is discharging into the surface water or surface water is moving into the sediments. This difference can be exploited to determine which direction the water is moving and, also, to estimate some hydrologic properties of the bed sediment. Quantitative estimates of streambed water fluxes into or out of the stream can be determined by using inverse modeling to fit simulated sediment temperatures to measure temperatures. In June 2005, a set of three piezometers were installed in the Bogue Phalia upstream from the stream gage near Leland, Miss., to monitor groundwater temperature. The piezometers were installed laterally across the stream and equidistant from each other. In each piezometer was an array of four temperature loggers deployed at 20cm, 50cm, 1m, and 2m below the sediment water interface. These loggers, plus one installed in the Bogue Phalia to measure surface water temperature, recorded temperature at 15 minute intervals. Precipitation in the Bogue Phalia Basin for the months of June to October 2005 was below normal, and consequently, the streamflow generally was below the long-term average. The temperature profile from the piezometers indicates that the Bogue Phalia was a gaining stream during most of this time. However, two anomalous precipitation events, Hurricanes Katrina and Rita, caused a sharp rise in streamflow over a short period of time. The temperature profiles indicated that warmer surface water was pushed into the stream bed. The temperature increased from 3 to 4 oC at the 2 meter depth, beginning soon after the stream started to rise. The increase in temperature at the other depths was similar, but commenced sooner, depending upon proximity to the surface. There were spatial differences in the temperature profiles. The west side of the stream was warmer than the east side, and the temperature changes occurred more rapidly on the west side than the east and more closely followed the hydrograph. The peak temperature corresponded with the peak of the hydrograph on the west side, but was offset on the falling limb of the hydrograph on the east side. This would indicate that the hydraulic conductivity of the bed sediments on the west side was greater than on the east side. As a quantitative tool, the U.S. Geological Survey (USGS) heat and groundwater transport model, VS2DI, was used to develop two-dimensional simulations of water fluxes into and out of the streambed sediments. Inverse modeling fits of simulated to measured sediment temperatures yielded estimates of fluxes across the streambed surface, which substantiated variations in hydraulic conductivity on the west versus east side of the Bogue Phalia site.
Survey of Invasive and Native Aquatic Plants in the Ross Barnett Reservoir
Year: Authors: Wersal R.M., Madsen J.D., Tagert M.L.
Ross Barnett Reservoir is a 33,000-acre impoundment on the Pearl River and serves as the primary source of drinking water for the City of Jackson. It also provides recreational opportunities in the form of fishing, boating, water sports, and onshore camping and hiking; activities that bring revenue to the state. Invasive aquatic plants have become increasingly troublesome in recent years, specifically impacting navigation, fishing, and reducing the aesthetics of waterfront properties. To assess the distribution and abundance of invasive species in the Reservoir a point intercept survey was conducted on a 300 meter by 300meter grid in June of 2005. A plant rake was deployed at each of the 1,423 points visited. The primary areas of infestations were in the shallow upper reservoir, Pelahatchie Bay, and along the eastern shoreline. Alligatorweed and American lotus were the most common plant species observed (10.0 % and 8.2% respectively), followed by pennywort (3.0%), water hyacinth (2.4%), water primrose (2.3%), and parrotfeather (0.4%). Plant species presence may be influenced by light availability in different locations within the reservoir as noted by light profiles. Light transmittance at all sites was less than 20% in the upper 1 meter of the water column. The exotic invasive species, especially alligatorweed and water hyacinth, due to their growth habits can infest a large area of the reservoir if left unmanaged.
Linking Watersheds: A Pilot Project in the Tombigbee-Mobile Bay Basin
Year: Authors: Tagert M.L., Jackson R., Reed L.E., Ballweber J.A., McAnally W.H.
Partnering among natural economic development, resource management, and conservation groups in the Tombigbee-Mobile basin offers the possibility for sustained collaboration on data and decision making for the basin. NOAA’s Coastal Services Center supported a pilot study that included workshops of key inland and coastal institutions to identify and integrate priority geospatial data and facilitate more effective and sustained stakeholder engagement. The primary partners on the project were Mississippi State University, Alabama Department of Conservation and Natural Resources, Tennessee-Tombigbee Waterway Development Authority, US Army Corps of Engineers Mobile District, Tennessee Valley Authority, Alabama SmartCoast, Tombigbee River Valley Water Management District, and the NOAA Weeks Bay Reserve. Data on the spread and flow of aquatic nuisance species, water quantity and quality, boundary and buffer information for wetlands and watersheds, fish and wildlife/water resources overlap information, water use, navigation, and bathymetric data were identified as most needed. A project web site containing survey results, a pilot database, and tools has been created to facilitate communication and data sharing.
Predicting Long Term Estuarine Sedimentation
Year: Authors: Savant G., McAnally W.H.
The purpose of this work is to develop an engineering method for predicting the morphologic behavior of estuaries. Where the river meets the sea, tides and density currents tend to trap sediments delivered by inflowing rivers, creating a natural sediment trap. For that reason estuaries can eventually fill with sediment and become tidal rivers. Human activities such as farming, mining, and dam building can accelerate or retard the infilling, as in San Francisco Bay and Atchafalaya Bay. Predicting estuarine infilling over long periods (decades to centuries) is made difficult by complex physical processes, highly variable sediment supply, and a lack of reliable long term data. Empirical orthogonal function (EOF) analysis, a technique for decomposing spatial and temporal data, was used to examine water depth trends in Suisun Bay, California. The analysis showed that EOF eigenfunctions demonstrate both depositional and erosive modes over a 40 year period and those modes can be correlated with freshwater and suspended sediment inflows with appropriate time lags. The findings suggest that EOF analysis can provide a method for predicting long term sedimentation, and experiments on larger and longer datasets are planned to develop the technique.
LMRFC Dambreak Operations
Year: Authors: Welch D., Lhotak J., Reed D.
The National Weather Service (NWS) has the responsibility to issue flood warnings regardless of a flood’s origin; including, those resulting from dam failures. The Lower Mississippi River Forecast Center (LMRFC) provides hydrologic forecasts and support to assist NWS Weather Forecast Offices in the issuance of flood warnings. When a dam failure occurs or has the potential to occur, LMRFC hydrologists use various forecast tools to develop dam break forecasts in providing this support. A basic component of the LMRFC dambreak operations is the NWS Dam Catalog (Damcat) database derived from the US Army Corps of Engineers, National Inventory of Dams (NID) database. In addition to the NID information, the Damcat database contains estimates of breach width, breach height, time to breach, forecast flood elevation and discharge at the dam, and the nearest downstream point of interest. Estimates of these parameters were developed from numerous historical dam breaks and provide general guidance that a NWS forecaster can quickly find and include in flood warnings. As time permits the LMRFC runs the NWS Simplified Dambreak model (SMPDK) to determine water surface elevations downstream of a dam failure. Inputs include estimated Damcat breach parameters, NID storage, and cross-sections derived from a commercial off-the-shelf mapping database. A Visual Basic GUI is available to refine the estimated breach parameters as needed. To ensure the quality control of all dam break forecasts, the LMRFC has developed "rules of thumb" based on numerous historical dam failures and hydraulic principles. These rules of thumb can also be used to provide general guidance so flood warnings can be released to the public in a timely manner to reduce the loss of property or lives.
Irrigation in the Mississippi Delta: A Historic Perspective
Year: Authors: Bryant-Byrd C.
In order to gain some insight into the present socio-economics of the Mississippi Delta, it is important to understand the past history of the region including its historical geology. The hydrogeologic setting of the Delta was influenced by its juxtaposition along the axis of the Mississippi Embayment, indirectly by the glacial episodes of the Pleistocene, but most significantly by the depositional and erosional sequences associated with meandering streams across the region during Recent times. Vast stretches of the Delta were covered in thick vegetation during much of its formative years. While large tracts were being cleared, the economy of the region was based predominantly on the cutting of virgin timber and the sawing and transportation of large volumes of lumber. As more cleared acreage became available during the 1800’s, the economy began a transition to that of more traditional agriculture with "King Cotton" reigning as the dominant commodity. The discovery of a prolific shallow aquifer underlying the Mississippi Delta was realized in the early 1900s. The water- bearing beds in the Mississippi River alluvium form the Mississippi River valley alluvial aquifer, the most extensive aquifer in the Lower Mississippi region. Pumping from the alluvium for irrigation began to gain momentum following a severe drought in the early 1950s. However, the number of alluvial wells in the Delta increased dramatically during the 1970s and 1980s with the introduction of pond-raised channel catfish to the region. The economy of the Delta today is dependent upon the alluvial aquifer as the source of water for over 14,000 irrigation and catfish wells.
A Climate-based management plan to conserve groundwater and reduce overflow in aquacultural ponds in the Southeastern U.S.
Year: Authors: Wax C.L., Pote J.W., Cathcart T.P.
The potential for conservation of groundwater used in warm water aquaculture in the southern region is evaluated. Daily water balances for ponds are constructed by computing precipitation minus 0.8 * pan evaporation over a 40-year period (1961-2000) at five sites in the region: Fairhope, AL; Clemson, SC; Thompsons, TX; Stuttgart, AR; and Stoneville, MS. Through computer simulation, daily water level fluctuations are controlled under two management schemes over the 40- year period: 1) pond surfaces are kept constantly at gage level by daily addition of sufficient groundwater to "make-up" evaporative losses not countered by precipitation, with excess precipitation lost to overflow; and 2) pond surfaces are allowed to drop six inches below gage level by cumulative evaporative loss not countered by precipitation, with addition of just three inches of groundwater at that point, leaving three inches of storage capacity for any subsequent excess precipitation. Amounts of groundwater used under the two management schemes are calculated and compared. Under the "make-up" water use method, amounts used range from about 34-44 inches across the region, and average about 38 inches annually. Under the alternative "6/3" method of management, amounts used range from about 4-15 inches regionally, and average about 11 inches annually. Implied conservation potential from adoption of the "6/3" scheme ranges from 64%-88%, and averages 72% for the region. Keywords: Climatological processes, groundwater, models
Water Quality in the Mississippi Embayment-Texas Coastal Uplands Principal Aquifer
Year: Authors: Welch H.L., Tollett R.W., Seanor R.C.
The Mississippi Embayment-Texas Coastal Uplands principal aquifer comprises the Mississippi River Valley alluvial aquifer and Mississippi Embayment and Texas Coastal Uplands aquifer systems, and is one of sixteen principal aquifers identified by the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program for further ground-water studies and regional synthesis of ground-water quality data. The principal aquifer covers approximately 197,187 square miles from southern Texas to southwestern Alabama and includes parts of Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, and Texas. According to 1990 water-use data, the principal aquifer ranks 9th in drinking water use, and 85 percent of the ground water withdrawn is used for irrigation, public-supply, industrial, and domestic needs. Three metropolitan areas use the principal aquifer as their primary source for drinking water - Memphis, Tennessee; Jackson, Mississippi; and Tyler, Texas. From 1994 through 2004, water-quality samples were collected at 169 domestic, monitoring, irrigation, and public-supply wells ranging in depth from 21 to 1466 feet below land surface. Dissolved-solids concentrations generally were less than the U.S. Environmental Protection Agency National Secondary Drinking Water Regulation (SDWR) of 500 milligrams per liter (mg/L). Thirty samples exceeded the SDWR, and two samples were slightly saline (>1000 mg/L in concentration). Calcium and sodium were the dominant cations, and bicarbonate, chloride, and sulfate were the dominant anions detected. Over half of the samples had concentrations above the SDWR of 300 micrograms per liter (ug/L) for iron and 50 ug/L for manganese. Trace element (i.e. aluminum, chromium, manganese, etc.) concentrations were low. Two values for lead exceeded the USEPA’s Maximum Contaminant Level (MCL) of 15 ug/L, and five values of arsenic were above the MCL of 10 ug/L. Of the 77 pesticides and 8 degradation products analyzed, 27 pesticides and 2 degradation products were detected in water from 53 wells. The most frequently detected pesticides were bentazon, simazine, atrazine, and metolachlor which are all herbicides. The highest concentration of a pesticide detected was 14.8 ug/L for 2,4-D, an herbicide used on agricultural crops such as wheat, sorghum, corn, rice, and low-till Non agricultural uses are in rights-of-way, roadsides, non-crop areas, forestry, lawn and turf care, and on aquatic weeds. One pesticide, atrazine, had a concentration of 3.14 ug/L that exceeded the MCL of 3.0 ug/L. Atrazine is an herbicide that is used to control broadleaf weeds and some grassy weeds. Thirteen values of nitrate plus nitrite were above 2 mg/L. Of the 87 volatile organic compounds (VOCs) analyzed, 35 compounds were detected in water from 108 wells. The most frequently detected VOC was 1,2,4-trimethylbenzene, which is a gasoline additive. The highest concentration of a VOC detected was 22 ug/L for diisopropyl ether, a solvent. All concentrations of nutrients and VOC’s were below MCL’s.
Environmental Relationships to Wadeable Stream Fisheries Resources in Mississippi
Year: Authors: Alford J.B., Jackson D.C.
Wadeable streams in Mississippi do not garner the attention of most anglers or fishery managers; consequently, these streams hold an unmanaged recreational fishery. However, they can support quality sizes and abundances of largemouth bass (Micropterus salmoides), spotted bass (Micropterus punctulatus), and sunfishes. We used the U.S. Environmental Protection Agency’s Wadeable Stream Assessment (WSA) to identify local and landscape-scale environmental features of Mississippi wadeable streams associated with relative abundances and size structure of catchable basses and sunfishes. In addition, we developed a testable regression model that can potentially be used as a rapid assessment tool to locate candidate streams in Mississippi that support a bass and sunfish fishery. Canonical correspondence analysis (CCA) suggested that increases in relative abundances of largemouth bass, longear sunfish (Lepomis megalotis), total bass combined and total sunfish combined were associated with small, meandering stream channels with residual pools, heavily forested watersheds and riparian canopy cover, and poor rapid habitat scores. Increases in relative abundances of spotted bass were associated with increasing stream size, flow and nitrogen concentration, decreases in channel incision height and sand substrates in favor of gravel and wood, as well as benthic macroinvertebrate assemblages with increasing proportions of scrapers and decreasing proportions of collector-gatherers and collector-filterers. These local-scale characteristics reflect forested riparian zones that minimize erosion and sedimentation from landscapes and supply woody debris for invertebrate colonization. In contrast, increases in bluegill (L. macrochirus) relative abundances were associated with more impacted systems, especially large, straight channels with open canopies, increased nutrient runoff, and landscapes with small to moderate increases in agricultural and urban cover (1-18% of watershed area). Our regression model suggests that, on average, as one proceeds towards the Mississippi Gulf Coast and 30 m wide riparian corridors are covered by increasing proportions of forest, then relative abundances and growth of age-1 of basses and sunfishes tend to increase. If this model can be validated, then fishery managers can use the model as a first-order assessment of wadeable streams in Mississippi with regard to their potential to support a recreational bass and sunfish fishery.
Runoff Losses of Pesticides and a Conservative Tracer from Warm-season Turf using Simulated Rainfall
Year: Authors: Ampim P.A., Massey J.H., Stewart B.R., Smith M.C., Johnson A.B., Maiers R.P., Andrews A.A.
This study is part of a larger national research effort designed to improve the understanding and modeling of turf pesticide runoff. The specific objectives of the project are to investigate the effects of warm-season turfgrass species, mowing height and plot size on pesticide runoff. The turfgrass species include bermudagrass (Cynodon dactylon [L] Pers. x Cynodon transvalensis Burtt-Davy) and zoygrass (Zoysia japonica Steud.). The turfgrass species were maintained as either golf course fairways or residential lawns. The runoff studies were conducted on eighteen 3.7 x 9.1 m and four 6.1 x 24.4 m plots. These plots were arranged in a split plot design and were sloped at 3 % with minimal cross slope. Following a standardized field protocol, 2, 4-D herbicide, flutolanil fungicide, and chlorpyrifos insecticide were co-applied at 1.12 kg ai/ha, 2.24 kg ai/ha and 2.24 kg ai/ha respectively. A conservative tracer, KBr, was also applied at 10 kg/ha immediately before initiation of simulated rainfall. Simulated rainfall was applied to the plots at a rate of 38 mm/h for 90 min. Runoff water from the plots was collected at approximately five-minute intervals. The runoff and application monitor samples were analyzed by reverse phase High Performance Liquid Chromatography (HPLC) using UV-Vis detection. Maximum observed concentrations (ppb), total masses (g) and percentages of applied chemicals observed in runoff water were determined.
Modeling the Big Black River: Evaluation of a Simplistic Water Quality Model
Year: Authors: Caviness K.S., Fox G.A., Deliman P.N.
The Mississippi Department of Environmental Quality (MDEQ) uses the Steady Riverine Environmental Assessment Model (STREAM) to establish permitted effluent limitations for industrial, commercial, and municipal facilities. While the U.S. Environmental Protection Agency (EPA) has approved of its use, questions arise regarding the model’s simplicity. This research first evaluated STREAM using a statistical evaluation procedure based on sensitivity analyses, input probability distribution functions, and Monte Carlo simulation with site-specific data from a 46-mile reach of the Big Black River in central Mississippi. STREAM reasonably predicted dissolved oxygen (DO) based on a comparison of output probability distributions with observed DO. The observed DO was consistently within 80% confidence intervals of model predictions. This research also evaluated STREAM by comparing observed DO with predictions by both STREAM and the Enhanced Stream Water Quality Model (QUAL2E). One version of the QUAL2E and STREAM models utilized site-specific input data. A second version of each model involved additional calibration. A third version of STREAM was an uncalibrated model developed following MDEQ Regulations (1995) for cases where intensive input data are unavailable. All versions of the models were simulated at the 7Q10 flow for the Big Black River, the minimum flow expected for seven consecutive days during a period of ten years. STREAM over predicted while QUAL2E under predicted DO with the site-specific input data. Percent errors ranged between 4.8% and 11.2% for STREAM and 3.3% and 5.1% for QUAL2E. The uncalibrated STREAM model predicted the lowest DO for all scenarios and correspondingly provided the most conservative DO predictions.
Greenhouse Modeling of Nitrogen Use Efficiency in Two Wetland Cyperus Species at the University of Mississippi Field Station
Year: Authors: Faulkner A.A., Holland M.M., Moore M.T., Cooper C.M.
Emergent wetland perennials are an effective component of wastewater treatment wetlands. Members of family Cyperaceae such as Scirpus, Carex, and Eleocharis are commonly used to treat nonpoint source contaminants. However, scientific literature regarding the use of the genus Cyperus as potential wastewater treatment species focuses on the C4 photosynthetic types, which comprise ~80% of this genus. The C4 pathway in Cyperus is evidently an adaptation to temperate wetlands and sandy, infertile environments (Li, et al., 1999). Cyperus species using the C4 pathway have a high photosynthetic nitrogen use efficiency (NUE), which appears to confer a high degree of success in wetland environments with low nitrogen concentrations. This translates to a possible competitive advantage over their C3 Cyperus counterparts where the latter conditions exist. Our six-month greenhouse experiment, which began in early December 2005, was designed to quantify and differentiate nitrogen use efficiency in two facultative wetland species: Cyperus haspan, a C3 sedge, and Cyperus strigosus, a C4 sedge. Both species co-occur in shallow wetlands and ditches at the University of Mississippi Field Station in Lafayette CO., MS; this situation presented the opportunity to determine each species’ response to long-term nitrogen dosing. Each species was subjected to nitrogen dosing regimens of both 2.5 ppm and 4.0 ppm, representing typical lower and higher nitrogen concentrations in agricultural runoff in Lafayette Co. Our expectations are that (1) Cyperus strigosus may have higher above- and belowground biomass in the low (2.5 ppm) nitrogen treatments than C. haspan at the same dose; (2) however, C. haspan may display higher above- and belowground biomass in the high (4.0 ppm) nitrogen treatments than C. strigosus at that dose level, and (3) photosynthetic pathway (C3 versus C4) may differentially affect the abilities of these two sedge species to sequester nitrogen in their tissues. The combination of both C3 and C4 sedge species planted in wastewater treatment wetlands and agricultural drainage ditches may be a more effective method of partially treating fluctuating levels of nonpoint source pollution than using either of the two types singly, since C3 sedges may function to remove nitrogen at higher concentrations while C4 sedges may be able to remove nitrogen more efficiently at lower concentrations.
Synthesis of Manganese Oxide Coatings for Adsorption of Trace Metals from Ground Water
Year: Authors: Tilak A.S., Williford C.W., Fox G.A., Sobecki T.
Manganese oxide (MnOx) occurs naturally in soil and has high affinity for trace metals such as lead, chromium, cadmium and zinc. Such heavy metals, when present in groundwater, will cause health risks if they enter aquifer drinking water sources. Our aim is to produce and characterize manganese oxide coatings on aquifer soil materials. The long term goal is to form a Permeable Reactive Barrier (PRB) to adsorb trace metals. Syntheses of manganese oxide coatings were carried out in the laboratory using continuous (column) reactor and batch reactor experiments on clean Ottawa sand. In the column experiment, manganese and bleach solutions were cycled alternately through a column of sand. The pH and ORP (Oxidation Reduction Potential) were monitored during coating process. The pH ranged from (4-9). The ORP was (600-800) mV when passing bleach and manganese solutions, and, (100-300) mV when passing DI-water. The coating process was carried out for increasing numbers of the cycles 24, 48 and 72. Flow rate was kept constant at 4ml\minute. After the coating process, a lead solution (50mg\L) was passed at 4ml\min through the coated sand to determine the lead adsorption capacity on manganese oxide coated sand. A lead selective electrode was used to plot breakthrough curves. The amount of lead adsorbed for 24, 48 and 72 cycles was 500mg\kg, 760mg\kg and 2106mg\kg respectively. An excavated aquifer soil will be investigated for coating synthesis and lead adsorption. The batch studies performed on Ottawa sand used three oxidants: ozone, hydrogen peroxide and bleach. For batch synthesis pH was investigated for a range of (6-9), and the initial amount of manganese was varied from 0.3 to 3.0g Mn per 100g sand. The manganese oxide formed on the sand ranged from 63.6mg\kg to 10372.8 mg\Kg. Results of batch syntheses indicate that manganese oxide on Ottawa sand increased with pH from 6 to 9 for hydrogen peroxide, ozone and bleach. Manganese synthesis was observed at the lower pH of 6 for bleach. Select coated sands from batch syntheses were also tested in column runs to determine lead adsorption. The batch synthesis was repeated three times on the same sand sample to examine the sequential buildup of manganese oxide coatings. The adsorption of cadmium, chromium, and zinc on the manganese coated sand was measured to determine relative/competitive adsorption capacity. Along with the experimental approach, modeling will allow us to estimate the service life for the Permeable Reactive Barrier to adsorb heavy metals.
Analysis of Mississippi and Alabama Water and Sediment Samples after Hurricane Katrina with H4IIE and YES Assays
Year: Authors: Emerson B., Argote K., Chaudhary A., Weston J., Khan S., Willett K.L.
Hurricane Katrina struck the Mississippi and Alabama Gulf Coasts on August 29, 2005. Following the extensive storm surges and flooding, this study was designed to test the toxicological effects caused by the storm. On September 13, 2005, the first water and sediment samples were collected with monthly collections following. Samples were collected from ten sites along the Alabama and Mississippi coasts: Mobile, AL, and Biloxi, Grand Bay, Gulfport, Ocean Springs, and Pascagoula, MS. Samples were extracted and filtered for analysis employing the H4IIE rat hepatoma and the Yeast Estrogen Screen (YES) Assay. The H4IIE assay is used to determine the induction of CYP1A by the presence of aromatic hydrocarbons. CYP1A activity is measured by the deethylation of ethoxyresorufin into a fluorescent pink product, resorufin (EROD). Maximal EROD activities for benzo(a)pyrene (BaP, 0.5 nM) and TCDD (0.5 nM) were 6.1 ± 0.05 and 3.0 ± 0.11, respectively. Ultimately activity from Katrina extracts will be expressed as percent of the highest concentration of BaP response measured in the EROD assays. The YES assay is used for predicting the presence of potential endocrine disruptors based on their binding and activation of the human estrogen receptor. The estrogen equivalents for the water samples ranged from non-detectable to 5.5 ng/L at a Grand Bay, MS site (site #8). The suspended sediment samples ranged from non-detectable to 1.4 ng/L at a Gulfport, MS site (site #2). By the February sampling, estrogen equivalencies for all but the Back Biloxi Bay site were below detection limits. Further analysis will be conducted with the H4IIE assay to measure CYP1A induction of the water and sediment samples. Results from the YES assay will be compared to NOAA’s pre-Katrina data, as available, with monthly collections and analytical chemistry data to follow.
Water Quality Study of Bays in Mississippi Following Hurricanes Katrina and Rita
Year: Authors: Cosgrove B.
EPA’s Region 4 Science & Ecosystem Support Division (SESD), in cooperation with the Mississippi Department of Environmental Quality (MDEQ), conducted a water quality study in the rivers and bays along the Mississippi coast following Hurricanes Katrina and Rita. The study was completed during the period September 26-30, 2005. The study area encompassed major bay systems on the Mississippi coast including Bangs Lake, Bayou Casotte, the Pascagoula and West Pascagoula River systems, the Back Bay of Biloxi, St. Louis Bay, and the Pearl River. The objective of this study was to provide sediment and water quality data in each major bay system along the Mississippi Sound. Flow was also measured at the seaward boundary of each system for estimating both conventional and toxic pollutant loadings entering the Mississippi Sound at the time of the study. This study was not designed to identify specific pollutant sources within each system or provide definitive information on the potential long term effects of the hurricanes on human or ecological health. Findings from the EPA and MDEQ joint survey of coastal Mississippi following Hurricanes Katrina and Rita showed few detectable priority pollutant type compounds in the studied bays and rivers. In general, the pollutants detected were low in concentration when compared to EPA’s National Ambient Water Quality Criteria for surface waters and the National Oceanic and Atmospheric Administration (NOAA) published effect levels for sediment. Dissolved oxygen concentrations were determined to be above the State’s adopted minimum criteria at all but two of the thirty-nine surface water locations. Bacteriological densities at the study locations were less than EPA’s promulgated enterococci criteria for coastal waters. Overall, the data collected by EPA shows that few water quality criteria were exceeded during the study. An exception was algal growth results in Back Bay of Biloxi and Bayou Casotte that exceeded 5 mg/l (dry weight). Dioxin results for the five sediment samples collected were all well below the EPA screening value for residential soils. The results of this study may be used as the basis for future targeted water quality studies by MDEQ and/or the EPA.
Summary of Bacteriological Data Collected at Coastal Mississippi Sites Following Hurricane Katrina, September-October 2005
Year: Authors: Rebich R.A.
On August 29, 2005, Hurricane Katrina devastated coastal Mississippi with 150 mile-per-hour winds and a storm surge in excess of 20 feet. Katrina moved inland and wreaked destruction on a broad swath of eastern Mississippi. Some eastern Mississippi counties were left without power and water, and some major roads were impassable for weeks. Disease transmission from contaminated water were major concerns. As part of a multi-agency response to the disaster, the U.S. Geological Survey (USGS), in partnership with the Mississippi Department of Environmental Quality (MDEQ), acquired temporary space at a USGS facility at Stennis Space Center near Bay St. Louis, Miss., to operate a bacteriological laboratory. Weekly bacteriological samples were collected at 31 estuarine tributary sites and 13 beach monitoring sites in coastal Mississippi counties - Hancock, Harrison, and Jackson - for a period of 5 weeks beginning September 19, 2005. Samples were collected by MDEQ and USGS personnel and transported to the laboratory for analysis within 6 hours of collection. USGS personnel analyzed the samples primarily for enterococci, which is the standard fecal indicator bacteria for brackish waters (and can be used as a fecal indicator for freshwater). Enterococci concentrations were determined by the most probable value (MPN) method. About 14 percent of the enterococci concentrations were less than the detection limit, and 81 percent were lower than current standards. The highest enterococci concentration was 24,200 MPN per 100 milliliters, which occurred at Bayou Chico at Pascagoula, Miss. Concentrations at most of the bacteriological sites increased during the second week of sampling due to runoff associated with Hurricane Rita rainfall that occurred September 23-24, 2005. The USGS also collected 19 water-quality samples at 12 inland freshwater sites for a period of 2 weeks starting on September 19, 2005. Sampling sites were located near established USGS stream gages. Physical properties of the streams were measured on site. Water-quality samples were collected, processed, and preserved on site according to standard procedures and then shipped to the USGS National Water Quality Laboratory in Denver, CO, for analysis, except for biochemical oxygen demand samples, which were analyzed by the MDEQ laboratory in Pearl, MS. Each sample was analyzed for multiple constituents including nutrients, major ions, trace metals, modern-use and polar pesticides, waste-water compounds, volatile organic compounds, and degradate organic compounds. Most detections were below current water-quality criteria for Mississippi streams. Overall, the results from the bacteriological and water-quality samples indicated no systematic contamination in the sampled streams in the aftermath of Hurricane Katrina. This project demonstrated to the public that both Federal and State governments were concerned about public safety, were willing to respond and to respond quickly, and performed their missions under highly unfavorable conditions. The data from this project are now available online at http://pubs.usgs.gov/ds/ds174/.
Storm Effects on Estuarine Water Quality
Year: Authors: Weston J.
In 2005 the northern Gulf of Mexico experienced 1 tropical storm and 4 hurricanes, hurricane Katrina being the largest, while the frequency and severity of tropical storms is predicted to increase due to global warming (Webster et al., 2005). To better understand the impact of these pulse disturbances on nearshore marine communities temporally and spatially explicit data are needed. Within Grand Bay, MS, the National Oceanic and Atmospheric Administration (NOAA) and the Mississippi Department of Marine Resources established a National Estuarine Research Reserve (NERR) to monitor water quality and other estuarine conditions. Four automated dataloggers have been collecting water quality data in Grand Bay NERR since 2004. Temperature, depth, specific conductivity, salinity, pH, dissolved oxygen, dissolved oxygen percent saturation and turbidity are measured every 30 minutes. Because of Grand Bay NERR’s temporal and spatial monitoring program a unique profile of storm related effects on abiotic factors has been captured but not analyzed. Water quality conditions before, during and after tropical storms and their change in magnitude and recovery to baseline conditions will be qualitatively and quantitatively assessed and compared within and between Grand Bay NERR sites. Data from last year, 2005, is currently being evaluated. Understanding the magnitude and duration of abiotic stressors in estuarine systems is a step toward developing better monitoring programs to assess ecosystem health and storm related disturbances.
Summary of Hurricane Katrina Storm Surge on the Mississippi Gulf Coast
Year: Authors: Wilson, Jr. K.V.
Hurricane Katrina made landfall on the coast of Mississippi and Louisiana as a Category 4 hurricane during the early hours of August 29, 2005. Following the path of Hurricane Camille in 1969, Katrina moved into Mississippi with 140 MPH winds and a storm surge reported to be 30 feet above sea level. The USGS coastal monitoring network was destroyed along with most of the buildings and structures within the inundated area. The USGS Hydrologic Instrumentation Facility (HIF) at Stennis Space Center served as a refuge for hundreds of people during the storm. The facility operated without power, water, and communications for several days while continuing to provide shelter for the families of HIF staff and local residents who lost their homes to Katrina. The Facility also served as a base of operations for USGS staff from other locations as response efforts got underway. Staff from the USGS Mississippi Water Science Center in Jackson deployed to coastal counties on August 31 to document storm surge elevations along the I-10 corridor, which is 6-10 miles inland. Initial data indicated that the storm surge varied from about 15 feet near the Alabama/Mississippi state line to about 28 ft in Hancock and Harrison Counties near St. Louis Bay. In the following weeks, USGS staff in Mississippi, Louisiana, and Alabama coordinated efforts with FEMA and The U.S. Army Corps of Engineers-Mobile District to complete the documentation of the storm surge elevation and extent. A comparison of storm surge data from Hurricanes Katrina and Camille indicates that the storm surge generated by Katrina exceeded Camille by 5 or more feet at all locations in Mississippi and exceeded the Camille peak by more than 10 feet in some locations in Hancock and Harrison Counties.
The Landscape Context of Plant Invasions in Mississippi Wetlands
Year: Authors: Ervin G.A., Linville M.J.
Invasive species are a known and growing threat to native ecosystems and the services they provide, and it is widely accepted that human activities contribute substantially to their spread. In a study of fifty-two north Mississippi wetlands, approximately 10% of the vascular plant species encountered were non-native, and 60% of the wetlands surveyed contained at least one plant species considered to be highly invasive. Furthermore, when highly invasive species were encountered, they were distributed across as much as 80% of the wetland area. Other work has shown that the degree of invasibility of a diversity of Mississippi wetlands was found to be much more strongly correlated with surrounding land use patterns than with the natural degree of connectivity among wetlands. For these reasons, we investigated the relationship of landscape features with exotic species richness in fifty-two freshwater wetlands across north Mississippi. Within those wetlands, invasibility was correlated only with certain forms of surrounding land cover, and inconsistently so. Agricultural land use appeared to enhance invasion of non-native plants, whereas density of surrounding wetlands and pine forest were correlated negatively with invasion. When wetland watersheds were classified based on the dominant land use as indicated by geospatial land cover data, no relationship was detected between dominant land use and degree of invasion. Indices of human activity surrounding the wetlands at the time of our vegetation surveys, however, did correlate closely with richness of exotic species, supporting the widely held notion that human alteration of the landscape can aid in the dispersal and establishment of non-native, weedy species.
Techniques for Managing Invasive Aquatic Plants in Mississippi Water Resources
Year: Authors: Madsen J.D.
Invasive aquatic plants are an ever-growing nuisance to water resources in Mississippi and the rest of the United States. These plants are generally introduced from other parts of the world, some for beneficial or horticultural uses. Once introduced, they can interfere with navigation, impede water flow, increase flood risk, reduce hydropower generation, and increase evapotranspirational losses from surface waters. Invasive species also pose direct threats to ecosystems processes and biodiversity. A variety of techniques have been used to manage these invasive plants in waterways around the United States. These techniques can be classified as Biological, Chemical, Mechanical and Physical techniques. Biological techniques utilize an herbivore or pathogen to control the plant, or reduce the equilibrium level of the population to an acceptable level. Chemical techniques utilize US EPA-approved herbicides to control plants, from small plots to large areas. Mechanical techniques utilize machines or tools to harvest, cut, pulverize or otherwise damage the plant. Physical techniques involve altering the environment to prevent or reduce the growth of invasive plant species. I will describe specific techniques and their potential niches for managing invasive aquatic plant species in Mississippi. I will also present some resources available for assisting in selecting the best technique, including the APIS system from USAERDC, available Best Management Practices plans, and information resources available from Mississippi State University.
Aquatic vegetation diversity in Lake Columbus, Lowndes County, MS
Year: Authors: Robles W., Madsen J.D.
Successful management of water bodies requires monitoring aquatic vegetation diversity and abundance. Lake Columbus was surveyed in July 2005 using a point intercept sampling method to determine the presence and distribution of aquatic plants. Using ArcGIS software, Lake Columbus was divided into a 400m x 400m grid in which each survey point was located with GPS using UTM coordinates. Aquatic plant species presence was recorded by deploying a plant rake. A GPS unit was used to navigate sequentially through each point location. A total of 72 points were surveyed resulting in 27 vegetated points and 45 unvegetated points. Eichhornia crassipes was the most common aquatic species observed (77.7%). Other nonnative aquatic plants observed were Hydrilla verticillata, Myriophyllum spicatum, Ludwigia uruguayensis, and Nelumbo nucifera. Native emergent aquatic plants observed were Justicia americana and Nelumbo lutea. The native submersed plant Ceratophyllum demersum was observed at 3.7% of vegetated points. Nonnative aquatic plants dominated the vegetation of Lake Columbus, indicating the need for aquatic plant management. Survey information incorporated into GIS layers is useful for management of invasive aquatic plants, biodiversity, and fish and wildlife resources.
Effect of sugarcane coverage on the behavior of Tebuthiuron in soil in Brazil
Year: Authors: Cerdeira A.L., DeSouza M.D., Ferracini F.L., Queiroz S.N., Bolonhezi D., Gomez M.F., Queiroz R.C., Balderrama O.
The region of Ribeirao Preto City located in Sao Paulo State, southeastern Brazil, is an important sugarcane, soybean and corn producing area. This region is also an important recharge area for groundwater of the Guarany aquifer, a water supply source of the city and region. The herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2 yl]-N,N’-dimethylurea) is regularly applied in the area. In order to understand the movement of tebuthiuron, the herbicide was applied at the recommended label rate with and without sugarcane coverage, on sandy soil area in Santa Rita do Passa Quatro County in Brazil, located in the region. Soil samples were collected at each 20 cm down to 120 cm and taken to the laboratory for determination of tebuthiuron. Tebuthiuron was measured at those depths mentioned before in ten intervals of time up to 300 days. Tebuthiuron halflives varied from 69 days in sugarcane cropped area to 49 days in non-cropped area. After 180 days there were no measurable residues in the soil and tebuthiuron was not found below 40 cm depth in any time.
Groundwater Resources of the Jackson Metropolitan Area
Year: Authors: Jennings S.
About 98 percent of the groundwater used in the tri-county (Hinds, Madison, and Rankin) Jackson metropolitan area is pumped from three major aquifers - the Cockfield, Sparta, and Meridian-upper Wilcox. Sand intervals within each of these major hydrostratigraphic units, though not strictly contiguous across the area, are present in significant thicknesses and with sufficient storage and transmissive properties to provide fresh water to 101 cities, water associations, industries, and other users within the Metro area. As an aid to all stakeholders, an on-going effort to better delineate the extent of the aquifer sand intervals through subsurface geologic mapping is being conducted by the Office of Land and Water Resources (OLWR) of the Mississippi Department of Environmental Quality. Structural mapping of the tops of pertinent geologic units and construction of several regional geologic cross sections have been completed as a first major step in this effort. Mapping of the total sand thickness for the Meridian-upper Wilcox aquifer has been completed, and mapping of the Cockfield and Sparta sands is proceeding. Concerns about water level declines in these aquifers prompted OLWR in 1997 to more closely monitor the water levels and publish summaries of the data. To this end a monitor well network of 83 wells has been used to periodically measure water levels and plot trends in the declines. The addition of the more recent water-level data with historical data indicate water level declines in the three main aquifers at average rates of approximately 1.5 feet per year in the Cockfield aquifer, 2.5 feet per year in the Sparta, and 2.6 feet per year in the Meridian-upper Wilcox. While of concern to all, these declines in water levels represent aquifer pressure declines and not actual dewatering. At the current rates of decline, the aquifers are capable of providing ample water supplies for many years. Linking the hydrologic data such as water levels and water quality to the geologic parameters such as depths and sand thicknesses is an anticipated step in the overall study of the groundwater resources of the area. Successful completion of this phase of the project along with the data and analyses outlined above should provide water resource planners and users valuable tools to utilize and manage this vital natural resource.
The Yalobusha River-Grenada Reservoir Watershed: Sediment Movement, Accumulation and Quality in a Mississippi Intensive Agricultural Landscape
Year: Authors: Cooper C.M., Smith, Jr. S., Ritchie J.
We examined sedimentation rates, current watershed contamination contributions and potential impacts of long-term row cropping (cotton, corn, soybeans, and sweet potato) on a small river and a large downstream flood control reservoir in the loess hills of Mississippi, USA. Grenada Reservoir (impounded in 1954) has a total watershed drainage area of ~3,419 square kilometers. Although reservoir life expectancy was originally estimated at 25 years because of high erosion rates in the watershed, our study revealed that the reservoir continues to function with only slightly reduced storage capacity. Sediment delivery to the reservoir by the Yalobusha River at the most downstream measured site from 1996 to 2002, averaged 126 mg/L (range 12 to 767 mg/L, S.D.=136). Long-term sediment accumulation within the permanent pool adjacent to the dam was <1cm yr-1 except for a depositional area near tributary inflow that accumulated sediment at about 5 cm yr-1. The central area of the permanent pool experienced sediment accumulation rates that averaged <1.5 cm yr-1. Sites within the two reservoir arms fed by the two river inflows (Yalobusha and Skuna rivers) showed little or no sedimentation. Sedimentation rates near the two river inflows were also generally low. A large debris jam which formed a river plug southwest of Calhoun City accumulated sediment from the upper portion of the watershed. From 1996 to 2004 analyses were conducted in water and sediment for 8 metals and 48 pesticides/contaminants at 26 stream/river locations and 9 locations within the reservoir. In spite of long-term historical use of residual pesticides in the watershed and widespread use of currently applied agricultural compounds, concentrations in stream or reservoir sediments and overlying water were generally low and sporadic or below detection. Conversely, several metals (arsenic, lead, copper, iron, aluminum and zinc) were abundant in stream and reservoir sediments. Atrazine, a widely used triazine herbicide, was routinely found in stream water and sediment. Atrazine was also detected in reservoir water samples but at only one fifth of contributing stream concentrations. Naturally-occurring aluminum and iron were found in high concentrations. Residual pesticides were generally not detected in water but were detected in stream and reservoir sediments. Sediments within the debris jam contained concentrations of arsenic and mercury lower than watershed and reservoir locations. Debris jam sediments also held highest observed concentrations of beta-BHC but did not contain detectable amounts of several legacy pesticides that were found in both the watershed and reservoir samples. A dredged channel through the debris jam was completed in late 2003. It may affect future sediment and contaminant accumulation in the natural river channel, its floodplain, and Grenada Reservoir. Because of processes associated with transitioning from a channelized stream to a natural one, it is likely that the plug phenomenon will reoccur. Keywords: Agriculture; contamination; sedimentation; pesticides; non-point source pollution
Measuring Streambank Erosion Due to Groundwater Seepage
Year: Authors: Fuchs J.W., Fox G., Wilson G., Simon A., Langendoes E.
The National Water Quality Inventory continues to report sediment as the most or at least one of the most severe pollutants of surface waters. Excessive sediment causes numerous water quality problems. It increases the potential for downstream flooding, diminishes water quality and destroys aquatic habitat. The two primary sources of sediment entering streams are erosion from adjacent landscapes and erosion of streambank sediment. Research on upland erosion has led to methodologies for controlling erosion from adjacent landscapes such as the use of best management practices. However, excessive sediment continues to be a problem throughout the United States. USDA-ARS scientists report that streambank material in many watersheds may contribute as much as 80% of the total sediment, especially in some watersheds in Mississippi. There exists a lack of information on one of the basic mechanisms governing sediment input to streams from the streambank: erosion by groundwater flow or seepage erosion. The importance of seepage erosion is not understood at this time, even though such an erosion mechanism has been observed throughout the United States. The objective of this research was to characterize streambank properties where seepage erosion contributes sediment to streams and causes bank failure and quantify subsurface flows and seepage erosion of bank sediment that results in bank failure at Goodwin Creek. Subsurface flows and sediment loads were quantified using lateral flow collection pans placed against exposed faces of the stream bank at pre-identified seepage locations when seepage was occurring. Subsurface flow and sediment concentrations were measured following rainfall events at both sites. These measurements were correlated to precipitation data, soil pore-water pressure measurements, and stream stages to ascertain the timing and importance of seepage erosion.
Influence of Slope on Streambank Seepage Erosion
Year: Authors: Gordji L., Fox G.A.
Erosion by lateral, subsurface flow is known to erode streambank sediment in numerous geographical locations. However, the role of seepage erosion on mass failure of streambanks is not well known. Previous research has investigated the mechanisms of erosions by concentrated, lateral subsurface flow and developed a sediment transport model for seepage erosion. As a continuation of this earlier research, slope destabilization driven by lateral, subsurface flow was studied to investigate the impact of slope on the suggested sediment transport model and to verify the model. Laboratory experiments were performed using a two-dimensional soil lysimeter. The experiments were conducted on two soils: a field soil (sandy loam) from Little Topashaw Creek (LTC) in Northern Mississippi and a sieved sand with greater sand content and less cohesion than the field soil. Simulated bank profiles were packed in the lysimeter with slopes of 60°, 75°, and 90°. Three zones of erosion were observed during the experiments: fluvial, sapping, and undermining zones. As opposed to the cohesion less sand soil, for LTC sand, a tension crack was not observed and bank failure did not occur for the 60° bank angle suggesting the importance of considering cohesion in bank failure analyses. Power law sediment transport models, derived based on a dimensionless sediment discharge and dimensionless flow shear stress in previous research, was investigated for dependency on slope. Observed sediment concentration data were compared to predicted sediment concentration data from the power law sediment transport model based on measured discharge. This research suggests that seepage erosion may be of critical importance for estimating sediment loads into streams by streambank failure even at relatively small streambank slopes. Kaywords Sediments, Groundwater, Hydrology, Water quality
Removal of Copper, Chromium, and Arsenic by Water Hyacinths
Year: Authors: Keith C., Borazjani H., Diehl S.V., Su Y., Baldwin B.S.
The removal of different concentrations of toxic metals by water hyacinths (Eichhornia crassipes) from a simulated aqueous environment was studied in an outdoor experiment. The hyacinth’s tissues were analyzed to evaluate the removal of copper (Cu), hexavalent chromium (Cr VI), and arsenic (As) from CCA (Chromated Copper Arsenate) contaminated water (5, 10, and 20 mg/L arsenic content, 7, 14, and 28 mg/L chromium concentration, and 2.5, 5, and 10 mg/L copper concentration) over a 17 day period. The vigor of the plants was also recorded during this period. The results showed that the hyacinth was not a suitable plant to remediate arsenic and copper. Arsenic removal for 5, 10, and 20 mg/L concentrations were 4.8, 4.7, and 0% respectively and copper removal for 2.5, 5, and 10 mg/L showed 53, 0, and 0% respectively. However, water hyacinth did show promising results as a hyper-accumulator of chromium. Percent chromium removal for 7, 14, and 28 mg/L contaminated water was 72.3, 21, and 19% respectively. The amount of copper in the containers with water hyacinths present was higher than the containers without plants (controls) indicating that the water hyacinth exudates might cause copper to stay in aqueous solution longer. As for the vigor of the plants, 5 and 10 mg/L arsenic concentrations damaged the plants somewhat over the 17 day period but overall these plants remained alive for the duration. Plants that were treated with 20 mg/L arsenic began to wilt and change color after day 1 and by the end were lifeless. Keywords: Treatment, Toxic metals, Water quality
Seasonal and spatial variation in phytoplankton community dynamics in Sardis Reservoir, Northeastern Mississippi
Year: Authors: Sthapit E., Ochs C.A.
Reservoirs, formed by river impoundment, can exhibit longitudinal spatial gradients in physical and chemical characteristics such as water transparency, chemical availability, and depth. Development and maintenance of these gradients is influenced by reservoir management operation affecting the rate at which water flows through the reservoir (hydrologic residence time). This research was conducted in Sardis Reservoir, in northeastern Mississippi. When flux of water out of the reservoir is restricted, as during the summer, hydrologic residence time increases and gradients develop in physicochemical characteristics along a transect from the riverine to the lacustrine (near dam) end of the reservoir. We hypothesized that, associated with these gradients, there would develop spatial variation in phytoplankton community composition, biomass, and productivity. To test this hypothesis, we made measurements over an annual cycle along the main longitudinal axis of Sardis Reservoir as well as in the embayment of three major tributaries. This reservoir, built for flood control, functions more like a lake during spring and summer when flood control gates are nearly closed, but more like a river during fall and winter. For examination of phytoplankton biomass and community composition we measured concentrations of taxon-specific photosynthetic pigments using high pressure liquid chromatography. Total phytoplankton biomass generally increased from spring through summer into fall. Based on indicator pigment concentrations, chlorophyte biomass peaked in summer, cyanobacteria were most common in summer and fall, and chrysophyte biomass peaked in both spring and fall. There were three distinct peaks in diatom abundance, one each in spring, summer and fall. Spatial heterogeneity in phytoplankton communities was most distinct in summer, especially between the two most distant sampling stations. The proportion of the total phytoplankton community of chlorophyll b, an indicator of chlorophytes, was consistently higher at the riverine end of the reservoir than at the lacustrine end. In contrast, the proportion of diatoxanthin, a diatom indicator pigment, was consistently higher nearest the dam in the lacustrine portion of the reservoir. Seasonal variation in phytoplankton community biomass, composition and productivity can be linked to seasonal changes in water temperature, light and nutrient conditions, along with hydrologic changes associated with reservoir operation.
Duplicity of wetland plants in nutrient flux within agricultural drainage ditches in Mississippi
Year: Authors: Kroger R., Holland M.M., Moore M.T., Cooper C.M.
Drainage ditches, as integral components of the agricultural landscape, remove surface run-off and act as major conduits of nutrients from agricultural lands to receiving waters. These ditches are filled with wetland plants, providing additional surface area for microbial interactions as well as acting in a small, yet important assimilatory capacity. However, their assimilatory function is negated in winter with seasonal die-back and the release of assimilated nutrients into the system. We tested the hypotheses of whether plants, given the opportunity, will firstly assimilate higher concentrations of nutrients, such as nitrogen and phosphorus, and whether with subsequent decomposition these concentrations are released back into the water column. Given the opportunity Leersia oryzoides, a dominant wetland ditch plant species, will assimilate significantly higher concentrations of nitrogen (p < 0.001) and phosphorus (p < 0.001) in aboveground biomass. Subsequently, the senescence of aboveground biomass yielded significantly higher levels of phosphorus (+ 5.2 mg/l). However, there were no significant differences in nitrate, nitrite or ammonia levels between treated and untreated treatments, suggesting that denitrification and microbial processes were removing these products from the system. Using Leersia oryzoides as our model the seasonal dieback and duplicity of drainage ditch vegetation in nutrient assimilation during the growing season and re-release of phosphorus in the winter will have effects on downstream environments. Key words: nutrients, wetland, assimilation, drainage ditch
Hydrologic Modeling of an Industrial Development Site
Year: Authors: McAnally W.H., Savant G., Ballweber J.A.
Environmental challenges associated with commercial, industrial, and residential development include site plans that minimize disruption of the natural hydrologic regime of the area, especially the impact on water quality. Site development plans that maintain the hydrologic regime and sustain water quality downstream are consistent with an approach described as smart growth. Significant advances have been made in the use of spatial models, including geographical information systems (GIS) and sophisticated hydrologic models, to assess the impact of potential development. Similarly, experience with best management practices (BMP) provides good insight into how various management practices such as stormwater detention and vegetated areas contribute to improved water quality. The purpose of this work is to determine if EPA’s BASINS GIS data and modeling system, including the hydrologic model HSPF, can be used to examine balancing watershed protection with low impact site development strategies. HSPF was applied to the Eurocopter factory site in Lowndes County, Mississippi as a test case. It showed that HSPF can readily model the hydrology of such a site and test common management practices, but the BASINS system design, which is intended for larger watersheds and simpler applications, makes it awkward to apply. Recommended actions to make the system more applicable include automating some manual procedures and creation of a simple graphical interface to facilitate site descriptions.
Hydrologic Operations of the Lower Mississippi River Forecast Center
Year: Authors: Roth K.
The National Weather Service Lower Mississippi River Forecast Center (LMRFC) is a multi-functional public service organization which uses cutting edge technology to prepare flood forecasts for dissemination to the public. The preparations of these forecasts are done daily using a combination of hydrologic experience, historical data, and real-time hydrologic / hydraulic models. The Sacramento Soil Moisture Accounting Model (SAC-SMA) is the soil moisture accounting model used at the LMRFC. The Dynamic Wave Operational Model is used for larger, more complex "mainstem" river forecasts, such as the Mississippi River. For most reaches, the Lag/K hydrologic routing technique is used. The forecast prepared using these models are disseminated to the public through the Weather Forecast Offices and in the form of a user friendly website. This website, along with all the graphics displayed on it are generated and maintained at the LMRFC. The LMRFC is responsible for preparing forecasts for a service area of approximately 220,000 sq. miles and parts of 12 states (fig. 1). Within this area, a network of 2900 rain and 500 river gages are utilized. These gages transmit information back to the LMRFC for use in the forecast model, which in turn is used to prepare five day forecasts. The data from these gages is used to prepare forecasts for 220 points. These forecasts are disseminated to the public every morning and updated as needed in times of flooding.
GIS and Remotely Sensed Precipitation Data for Watershed Models
Year: Authors: Wasson L.
The Upper Pearl Watershed located in central Mississippi covers over 2000 square miles in 15 counties. The environment of the Upper Pearl Watershed is rapidly changing due to residential and commercial development in the Jackson metropolitan area, the state capital, and further upstream near Philadelphia, MS. These changes may present water quality challenges to both the Pearl River and the Gulf of Mexico coastal waters. Heavy precipitation events in Upper Pearl can significantly impact coastal fisheries and essentially close near shore oyster reefs for several days until the transported pollutants from the Pearl River dilute to safe levels. Modeling the relationship between meteorology and climatology and water quality could provide valuable management insights to upstream managers on downstream, coastal impacts. Developing such a model faces some daunting challenges. Surface weather stations are the typical source for meteorological data but the distribution of these stations results in large spatial gaps in data coverage. It can rain in one part of the watershed but never be recorded and placing a weather station every few kilometers would be unrealistic. This paper examines the validity of using remotely sensed meteorological observations using NASA’s Tropical Rainfall Measurement Mission (TRMM) satellite, NOAA’s Multi-Precipitation Estimate (MPE) and GOES satellite Hydro Estimator (HE). Arc Hydro, ESRI’s new water resources data model, will systematically bring in the different data formats for use in the Army Corps of Engineers HEC simulation models.
Simulating the Erosion of Streambanks by Lateral, Subsurface Flow
Year: Authors: Fox G.A., Wilson G.
Sediment from agriculture impairs more stream miles on the US EPA’s Clean Water Act 303(d) list than any other contaminant. As much as 80% of the sediment entering streams in some agricultural watersheds originate from the streambank. Fluvial processes are generally the only mechanisms considered in contributing to streambank erosion. Limited information exists about lateral, subsurface flow as a mechanism of streambank erosion, even though subsurface flow erodes streambank sediment in numerous geographical settings. The objective of this research is to evaluate the importance of subsurface flow erosion and quantify the contribution of streambank erosion by ground water mechanisms. Field experiments are performed at Little Topashaw Creek (LTC) within the Yalobusha Watershed in Northern Mississippi. Streambanks at LTC are commonly stratified consisting of alternating layers of alluvial sand and clay. Initial soil characterizations are performed at three identified sites where subsurface erosion of LTC streambank sediment is occurring. The potential for substantial, lateral subsurface flow is prevalent due to alternating layers of less permeable clay and high conducting sand below a layer of topsoil. Laboratory analyses on each soil type indicate a considerable hydraulic conductivity and water retention contrast and therefore a substantial difference in the flow characteristics of each of these horizons. Intermediate scale experiments are performed using lysimeters constructed to simulate LTC streambank soil profiles and instrumented with an array of minitensiometers for soil water measurement. The lysimeters simulate the dynamics of bank undercutting due to sediment loss as water flows through the more permeable sand layer, causes sapping erosion and undermining of the sand, and eventual bank collapse of the overburden or topsoil. Lysimeter experiments are performed with varying boundary conditions including hydraulic gradient, overburden height, and lysimeter slope. Conclusions are drawn regarding the relative importance of each of these boundary conditions on the subsurface erosion process.
GIS Geodatabase Model Building for Road Management: The Army Corps of Engineers Tennessee-Tombigbee Waterway (Mobile District)
Year: Authors: Jackson R.
The Army Corps of Engineers Tennessee Tombigbee Waterway located in the Mobile District, is responsible for 234 miles of the Tombigbee River. On both sides of the river, roads are used to manage the river and the activities associated with the river. The Corps has approximately 53 miles of paved roads and 130 miles of unpaved roads. These roads have various functions. Roads are used as access roads into the waterways ten locks and dams, as well access into roads into campground and day camp use facilities. Managing the maintenance of these roads can prove to be difficult without an appropriate system set in place to record and update road maintenance projects. Accordingly, the Corps is developing a geographic information system (GIS) geodatabase to assist in these activities. A GIS geodatabase stores spatial as well as attribute data. The key component in the geodatabase is its ability to efficiently relate spatial data and attribute data in a management system. The geodatabase will be used in conjunction with PAVER, Pavement Maintenance Management System, a pavement inventory software and DYNASTAR, Millwide Maintenance Management System, a inventory maintenance activities software to help the Corps more efficiently plan and prioritize their long term maintenance needs and manage day to day roads management. A data model of the Corps GIS geodatabase, along with Paver and DynaStar is being built using Microsoft Visio 2002. Visio is a diagramming program that can be used to illustrate complex databases. A data model shows how the geodatabase is constructed, and how each of components in the geodatabase is related. A diagram of the geodatabase of the Corps roads network would enable Corps personnel to quickly distinguish how each component of the network interrelates, making it a valuable decision making tool.
Soil resilence in disturbed forests and associated wetlands following timber harvest
Year: Authors: Rajkarnikar B., Holland M.M.
This research focuses on quantifying the resilience of disturbed forested wetland habitats by studying the physical and biogeochemical properties of soil. The need for knowledge about ecosystem resilience following disturbance is becoming more critical for curbing the loss of natural resources. Using soil parameters as environmental indicators may lead to a better understanding of managing these resources. The aim of the study is to estimate resilience data from the study site and incorporate it with similar pre-existing studies to provide a wider perspective on soil processes occurring throughout the watershed (the Yazoo-Tallahatchie River Basin). Soil samples were taken from three disturbed sites of different ages (6 months, 7 years and 18 years since last harvest) and one undisturbed site (94 years since last harvest) from Northern Webster County, Mississippi. Six sampling points -three uphill and three streamside- were sampled in each of the sites. Soil samples were tested for concentrations of Total Soil Organic Matter (SOM), Total Carbon (TC), Total Nitrogen (TN), Total Phosphorous (TP), pH, Compaction, and Moisture Content. The TC and the Soil Compaction showed a decreasing trend with increasing age of the sites, with the 6 months site showing the highest values. The moisture content in the 7 year site was significantly lower than other sites, and 6 month streamside samples had significantly higher moisture content than uphill samples. TP was highest in the 6 month sites, followed by the uncut sites. There were no differences in SOM and TN levels among all sites, but a consistent trend of an initial decrease and a gradual increase can be observed in comparisons between pre-researched sites within the watershed. A Soil Perturbation Index (SPI), which incorporates these soil parameters and predicts the regeneration period needed for the disturbed areas with respect to the undisturbed reference sites, has further explained the biogeochemical dynamics of the study sites. Data from past sites within the watershed ( in Calhoun, Issaquena, Leflore and Lafayette Counties, MS) where similar studies have been conducted have been compared to project a comprehensive picture of the biogeochemical processes taking place within the watershed’s timber producing forests and associated wetlands. The results of this study will be beneficial for forest and wetland resource user groups in the region such as foresters, landowners, timber companies, farmers, conservation and government agencies, and the local stakeholders in utilizing and sustainably managing the available natural resources.
An eight-year vegetative survey of long-term monitoring plots (LTMP’s) at the University of Mississippi field station
Year: Authors: Faulkner A.A., Holland M.M.
Since 1996, the Department of Biology at The University of Mississippi has been taking biannual surveys of both understory and overstory vegetation in the Long-Term Monitoring Plots (LTMP’s) at the University of Mississippi Field Station (UMFS) in Bay Springs, Mississippi. Twenty 400-square meter plots were randomly selected from 302 possible plot sampling sites on the over 296- hectare property. Land use maps were created and used to determine both past and future plant community changes, as well as land and natural resource management of these areas. Basic understory parameters such as species richness, foliar cover, species frequency, and foliar density have been compiled for 1996, 1998, 2000-2001, and 2003-2005, to monitor both the rate and dynamics of vegetative changes over time in these ecologically diverse plots. The purpose of this data compilation is to assess any vegetative changes that may have occurred over an eight-year period in the LTMP’s. Of particular interest are any changes in species numbers of woody versus herbaceous plants, and also the species numbers of introduced versus native plant species (Mastin 1996; Holland and Chambers-Strong 2001).
Bacterial source tracking of a Prairie Watershed System using AFLP
Year: Authors: Rivera C., Sullivan S., Prewitt M.L., Diehl S.V., Evans R.
Bacterial contamination of groundwater is a key concern in developing environmental protection regulations. Bacteria originate from many different sources, and determining the source is essential in order to reduce the contamination in our watersheds. Since 2002, MAFES and the Forest Products Lab have been tracking the numbers of three different fecal coliforms-E. coli, Enterococcus, and fecal Streptococcus-from a watershed impacted by beef cattle production (located at the MAFES Prairie Research Unit). These data were used to demonstrate the seasonal and site fluctuations from four locations; pristine (no cattle, no humans), high-load prairie (125-150 cows with calves on 275 acres), variable-load prairie (125 acres), and normal roadside runoff (human contribution). There are significant bacteria contributions from wildlife (especially blackbirds) during certain winter months and from humans on occasion. In order to determine the contribution of the beef cattle to the watershed contamination, an E. coli library is being built for the Prairie cows. Thirty-five samples were collected from cow patties at the Prairie station, fecal coliforms were isolated and confirmed on selective media, and stored in a -70°C freezer. DNA is being extracted by two procedures, and subjected to AFLP. AFLP will be used in this research because it can distinguish between closely related strains. Once complete, the AFLP library will be evaluated for selectivity to cow fecal coliform and, if successful, used to track the contribution of cows to the watershed contamination under best management studies.
Improved Irrigation Efficiency and Reduced Surface Water Contamination Using Intermittent plus Multiple-Inlet Irrigation in Rice Production
Year: Authors: Smith M.C., Massey J.H., Vories E., Johnson A.B., Andrews A.A., Ampim P.A., Talbert R.E.
Increased competition for finite water resources, and concerns over groundwater depletion, will reduce the amount of irrigation water available for future agricultural production. Our project aims to reduce water use in rice production by coupling intermittent irrigation with multiple-inlet irrigation techniques. The combination of these techniques at the production-scale has not been investigated, but preliminary research indicates that the combination may reduce water use by as much as 50% over conventional (continuously flooded) practices without significantly affecting yield. Reduced irrigation pumping of rice fields will also increase the rainfall holding capacities of rice paddies, resulting in less non-point source agrochemical contamination. A production-scale project was begun in Mississippi and Arkansas in 2004 to compare water consumption, agronomics, and non-point source runoff in continuously flooded and intermittently flooded rice systems. A total of five producer sites were located in Mississippi (3) and Arkansas (2); field sizes ranged from ca. 27 to 40 A. Rice yields, pest levels, water use rates, rainfall holding capacities in paddies, and non-point source runoff potentials for rice pesticides and nutrients were determined. As expected, the rice producers were initially uncomfortable with allowing the flood in the intermittently flooded field to subside to the target depth, resulting in similar water use during the first 30 days after flood initiation. As their initial reluctance was overcome, the daily irrigation rate typically dropped from ca. 0.35 A-inch/day in the continuously flooded fields to ca. 0.16 A-in/day in the intermittently flooded systems. The continuously flooded system typically used a total of ca. 30 A-in of water as compared to ca. 20 A-in in the intermittently flooded systems. Disease and weed infestations did not differ significantly between the two rice flood systems. At the one producer site where rice yields were available at the time of this writing, rice grown in the intermittently flooded system yielded ca. 189 vs. 183 bu/A from rice in the continuously flooded system. Analyses of water samples used to compare non-point source runoff potentials between the two systems are on-going, as are tabulations of rainfall holding capacities for the study sites.
Using the AGNPS Model and GIS to Locate Areas that May Be Vulnerable to Runoff
Year: Authors: Tagert M.L., Shaw D.R., Massey J.H., Bingner R.L.
The USDA Agricultural Nonpoint Source (AGNPS) runoff pollution model is being used, in combination with geographical information systems (GIS) and remote sensing, to predict water, sediment, and pesticide nonpoint source runoff in the uppermost portion of the Pearl River Basin. The AGNPS model includes a GIS interface that processes a digital soils layer, digital elevation models (DEM), digital land cover from Landsat satellite imagery, climate stations, and other inputs to the AGNPS model. AGNPS, using the DEM as the main input, performed a topographic evaluation of the watershed, drainage area identification, synthetic channel networks, watershed segmentation, and subcatchment parameters. Two National Weather Service (NWS) rain gauges were located within the drainage area at Louisville and Gholson, and one additional gauge was just outside the drainage area at Philadelphia. Measured precipitation data was obtained from January 1994 through December 2003 for these three gauges. Thiessen polygons were created to determine the weighting of the rain gauges for precipitation values over the drainage area. Once the watershed segmentation was performed and subwatershed cells were delineated, the AGNPS GIS interface intersected the soils, land use, and climate information with the subwatershed cells. The Input Editor component of the model was then used to combine all necessary information, such as climate data, watershed cell and reach data, and management information into an input file that was utilized by the pollutant loading portion of the model. For the ten-year period that was modeled, AGNPS predicted the average annual rainfall for the watershed to be 1450 mm, with a watershed average annual loading of 463 mm. Sediment loading (clay, silt, and sand combined) at the outlet was predicted to be 27 mg/ha/yr, and nitrogen loading (dissolved and attached) was predicted at 19 kg/ha/yr. Average annual loading was predicted to be 284 and 67 kg/ha/yr for organic carbon and phosphorus, respectively. Results of the AGNPS DSS are also being analyzed for pesticide runoff, as well as for specific rainfall events, and compared to measured results for validation.
Analytical eetection and quantification of chemical mixtures: WNV eradication compounds and other xenobiotics
Year: Authors: Weston J., Slattery M.
Persistence of West Nile Virus (WNV) throughout the United States, particularly in the Mississippi Valley States, supports the continued efforts to control mosquito vectors such as Culex spp. Chemical agents commonly used to control mosquito vectors are nonspecies specific pesticides that may potentially interact with non-target aquatic organisms. Through direct or indirect routes these compounds eventually become part of water and sediment matrices. Individually or as mixtures with other co-occurring persistent or transient xenobiotics, e.g. agricultural and urban pesticides, these anthropogenic compounds can potentially degrade the water quality and aquatic habitat of aquatic organisms. Our group will present preliminary findings which are part of a multi-year study evaluating the co-occurrence and ecotoxicity of vector eradication compounds individually and in mixtures with agricultural and urban pesticides. Currently, development of analytical methods focused on the model mosquitocide methoprene, a commonly used mosquito larvicide, and chlorpyrifos, a commonly used organophosphate pesticide (chlorpyrifos has recently been severely restricted in indoor and outdoor residential/business use but continues to be used in agriculture). In our effort to evaluate the habitat quality along Mississippi’s and Alabama’s coasts water and sediment samples collected from these areas will be assessed using the analytical methods presented in this poster.
Conservation Effects Assessment Project (CEAP)-Watershed Assessment Studies: Yalobusha River Watershed
Year: Authors: Wilson G.V., Reid P., Shields F.D., Dabney S.M., Oldham L., Romkens M.J., Cooper C.
The USDA ARS-NRCS has established a joint Conservation Effects Assessment Project (CEAP) that will assess the environmental benefits due to conservation practices on 12 benchmark watersheds. The Yalobusha River Watershed (YRW), which covers 168,750 ha consisting of 18% cropland, 19% pasture areas, 53% forested areas, 6% wetland, and 4% surface water, was selected as a benchmark watershed. The MLRA for the YRW is Southern Coastal Plain with alluvial soils comprised of dispersive silt topsoil over sand and clay layers overlying consolidated clay. Major features of the river system include: 1) erosion-resistant cohesive streambeds; 2) channelized stream network; 3) channelized main stem terminates in an narrower unmodified, sinuous reach; and 4) a debris plug on the lower end of the channelized main stem. The YRW experiences deposition and flooding problems in downstream reaches and excessive erosion via gully inlet erosion and bank failures along upstream reaches. The major water quality issue is sediment. Historically high rates of sediment yield reached levels about twice the national average. Other contaminants include residual organochlorine insecticides, some current use insecticides, metals (e.g. mercury and arsenic), atrazine, and coliforms. The objectives of the CEAP activities for YRW are: (1) Synthesize baseline data by (i) working with USGS, NRCS, CoE and other agencies to identify and locate Cps, (ii) acquire topographic and soils data in digital format, and (iii) compile historical hydrologic and water quality data including: precipitation, streamflow, suspended-sediment, nutrients, and pesticide concentrations; and (2) Quantify the water and contaminant transport processes at different scales by (i) evaluate the juxtaposing of two or more practices (eg. an in-field and an edge-of-field practice), (ii) conduct upstream/downstream comparisons, and pre/post implementation comparisons, and (iii) conduct thorough site investigations to define a mechanistic understanding of CP function. Research will focus on evaluating field and stream responses to drop pipe and riparian forest buffer conservation practices. Fields with and without these practices will be instrumented for runoff and sediment transport measurement along with upstream and downstream measurements in the stream.
Subsurface band and Surface broadcast Application of Broiler litter: Effect on Soil Nitrogen Spatial Distribution
Year: Authors: Armstrong S., Tewolde H., Way T., Rowe D., Sistani K., Taylor R.W.
Nitrogen content of broiler litter is vulnerable to volatilization loss when litter is surface-applied to fields as a fertilizer. Recently, researchers of the USDA-ARS at Auburn, AL have designed a new implement that applies litter in bands under the soil surface. Field research was conducted at the North Farm of the Mississippi Agricultural and Forestry Experiment Station in Starkville, MS to compare the effect of the new subsurface band application and the conventional surface broadcast application of litter on soil nitrogen distribution and concentration. Fertilizer treatments included no fertilizer (control), Broiler litter (BL) surface broadcast before planting at 6720 kg ha-1, and (BL) broiler litter subsurface banded at 20-cm from the center of the cotton row before planting at 6720 kg ha-1. Soil samples were taken at 24 and 73 days after BL application at 0, 10, 20, 30, 40 cm from the cotton row. Soil analysis results showed that application method does have an effect on the available N pool. When the litter was subsurface banded NH4-N was only elevated 20-cm from the center of the cotton row, where the BL was subsurface banded, 24 days after application. Yet, the average concentration of NH4-N across all sampled positions at the 0-15 cm depth was 47% greater when PL was subsurface banded than when BL was surface broadcast applied. The subsurface band NO3-N concentration 24 days after litter application at the 20-cm position was significantly higher than the broadcast and the control and 73 days after litter application at 0-15cm depth, the band NO3 -N at the same sampling position was 25% higher than the broadcast or the control. These results suggest that applying broiler litter in bands under the surface can have a positive effect on the spatial distribution and concentration of inorganic soil N in close proximity to the root zone of cotton.
Isolation of Salmonella Bacteriophages from Swine Waste Lagoons
Year: Authors: McLaughlin M.R., Balaa M.F., Rowe D.E., Sims J., Andersland J., King R.
Bacteriophages (phages), viruses that infect bacteria, occur wherever bacteria occur. Like other viruses, phages infect specific hosts. Phages which infect and lyse their respective host bacterium are called lytic phages. Specificity of lytic phage-host relationships is the basis of phage typing, which is used in identification and tracking of human bacterial pathogens, including Salmonella. Lagoon samples from nine hog farms in Mississippi were tested for the presence of phages and Salmonella-specific lytic phages were isolated. Phages were isolated using an enrichment method or directly from clarified filtered effluent. For enrichment, samples were treated to eliminate bacteria, then mixed with nutrient broth containing a Salmonella cocktail (serotypes Typhimurium and Enteritidis) to favor growth of Salmonella phages. After overnight incubation, Salmonella were killed and enriched samples were tested by double agar layer (DAL) plaque assays against individual Salmonella isolates. Enrichment produced lytic phage titers of 2.9 x 108 to 2.1 x 109 plaque forming units (pfu) per ml. For direct isolation, effluent was clarified by centrifugation and filtration, then used in DAL plaque assays against host isolates of serotypes Typhimurium; Enteritidis; Agona; Michigan; Montevideo and Gaminara. Isolates were recovered by the direct method for all serotypes except Gaminara, but plaque formation varied among host isolates and lagoon samples. The most sensitive host for direct isolation of phages was S. typhimurium ATCC 13311. The direct method was used with ATCC 13311 to estimate phage titers among the lagoons, which ranged from 12-148 pfu per ml. Host range tests of phage isolates from enriched samples, showed all were specific for S. enteritidis and S. typhimurium and none produced plaques on lagoon isolates of Citrobacter youngae, Escherichia coli, E. fergusonii, Proteus mirabilis, Providencia rettgeri or Serratia marcescens. Electron microscopy (EM) with enriched samples showed phages with icosahedral heads about 50 nm in diameter with tail spikes, but lacking a tail shaft. EM of concentrated filtered lagoon samples, without selection for Salmonella specificity, revealed other phage types, including tailed phages. Swine waste lagoons proved to be rich in phages and good sources of Salmonella phages. These phages have potential uses in phage typing and as Salmonella indicators and biocontrol agents.
Fungicide-Based Estimates of Yield Losses Caused by Fungal Diseases in Bermudagrass on Swine Waste Application Sites
Year: Authors: Pratt R.G.
Bermudagrass (Cynodon dactylon L.) is one of the principal forage grasses to which swine wastes are applied for the uptake and assimilation of phosphorus (P) to prevent its movement into surface waters to cause eutrophic pollution. Fungal plant diseases that reduce the yield and survival of bermudagrass may limit its usefulness for the uptake of P from applied wastes and prevention of water pollution. Previous observations indicated that fungal diseases of roots, rhizomes, and stolons may be major factors that limit forage production and P removal by bermudagrass on swine waste application sites. Therefore, this study was undertaken to provide quantitative estimates of yield losses caused by fungal diseases in bermudagrass sod on three swine waste application sites in Mississippi. In 17 experiments, samples of sod from areas of stands with disease symptoms, or from healthy-appearing areas, were collected, potted up in the greenhouse, clipped, and grown for 5-10 weeks with or without weekly fungicide drenches applied to sod. Foliage then was harvested and dry weights were determined. Losses in forage yield were estimated according to differences in foliar dry weights between untreated controls, where development of fungal diseases in sod was unimpeded, and in pots with weekly fungicide drenches, where disease development was suppressed or arrested. Of four fungicides tested, mancozeb usually gave the greatest growth responses and the highest yield-loss estimates. In 12 experiments with samples of diseased-appearing sod from three commercial swine farms, estimates of losses in potential forage yields obtained with mancozeb ranged from 0-68% with a mean loss estimate of 44%. In five experiments with samples of healthy-appearing sod, loss estimates obtained with mancozeb ranged from 0-35% with a mean loss estimate of 17%. Significant differences in disease losses between sites were observed. Results indicate that on some swine waste application sites, major losses in forage yield of bermudagrass are occurring as a result of fungal diseases in roots, stolons, and rhizomes. Genetic improvement of bermudagrass for disease resistance, or the development of other effective control measures, could greatly increase its capacity for forage production and P removal on some swine waste application sites.
Environmental Stewardship Education for Mississippi Agricultural Producers
Year: Authors: Holder T.S., Oldham J.L.
Agricultural related water quality concerns are major issues throughout the country, the south, and Mississippi. At one time, Mississippi accounted for 61% of the stream miles listed in the United States as impaired by pollutants such as sediment, nutrients, and pathogens. Several actions have improved the situation in recent years: improved monitoring, an active Total Maximum Daily Load (TMDL) program, improved interagency networking, and educational efforts. Each state has unique watershed and commodity specific factors to consider in developing effective educational programs to build awareness of the issues, challenges, and opportunities, and foster voluntary and positive environmental actions. Louisiana State University developed an Environmental Stewardship educational module in an agricultural proficiency "Master Farmer" program. For the stewardship module, multiple state agencies and advocacy groups developed a three tier process by which farmers receive instruction on environmental issues, participate in Best Management Practice demonstrations, and develop Conservation Plans. By late 2004, over 2400 farmers have participated in the educational phase of the program, and are continuing in the subsequent processes through development of model farms and conservation plans. Based on needs assessment surveys among stakeholders, Mississippi State University Extension Service, with Mississippi-based agency and advocacy group partners, began development of a watershed-based agricultural-environmental stewardship educational program named Medallion Producer. While similar to the Louisiana effort, the name was changed to avoid client confusion with other Extension programs with the "Master" designation which require volunteers pay back time in return for a higher level of specific subject matter instruction and training. Curriculum materials, lesson plans, and an outreach plan are being developed for the Medallion Producer effort. Curriculum subjects include water quality issues, laws, and regulations, agricultural air and soil quality issues, conservation/reduced tillage, Integrated Pest Management, nutrient management, structural soil management measures, the roles and duties of Conservation Districts, the Natural Resource Conservation Service, and other agencies, Best Management Practices, and relevant cost-share programs. Implementation of the Mississippi program will begin in 2005. In addition to the Mississippi and Louisiana efforts, this model is being developed in several other states through the Southern Region Extension Water Quality Program.
Developing Plans for Managing Invasive Aquatic Plants in Mississippi Water Resources
Year: Authors: Madsen J.D.
Invasive aquatic plants are an ever-growing nuisance to water resources in Mississippi and the rest of the United States. These plants are generally introduced from other parts of the world, some for beneficial or horticultural uses. Once introduced, they can interfere with navigation, impede water flow, increase flood risk, reduce hydropower generation, and increase evapotranspirational losses from surface waters. Invasive species also pose direct threats to ecosystems processes and biodiversity. All agencies and individuals responsible for water resources in Mississippi should be prepared for invasive aquatic plants through developing an aquatic plant management plan. Components of a plan include: Prevention, Problem Assessment, Project Management, Education, Monitoring, Site- or problem-specific management goals, and Evaluation. Prevention seeks to reduce the influx of new invaders into the resources, and respond rapidly once they are found. Problem assessment is to quantify the distribution and abundance of the target plant and its impacts on the resource. Project Management includes tracking available resources to fight the problem, including funds and labor. Education involves informing both the resource agency and the public in the problem and potential solutions. A monitoring component tracks the general condition of the resource in both biotic and abiotic attributes, to detect other changes associated with the resource. Site- or problem-specific goals addresses the management of target species based on a specific site basis, rather than attempting to find a single solution to the target plant problem through time for all locations. Finally, an evaluation plan quantifies the success of the management efforts based on economic, environmental, and efficacy thresholds. These components in a management plan will increase the likelihood of a successful approach to invasive plant problems. Keywords: Invasive Species, Management & Planning, Recreation, Wetlands
An approach to incorporate invasive species and wetland indicator status into wetland floristic quality evaluation
Year: Authors: Ervin G.N., Herman B.D.
We evaluated four potential indices of wetland floristic quality, based on the general Floristic Quality Assessment Indices (FQAI) that have been developed and used extensively in various regions of the United States. The four indices that were evaluated, termed Floristic Assessment Quotients for Wetlands (FAQWet), incorporated components of overall species richness, wetland affinity, and the contribution of native versus exotic species to overall wetland vegetation quality. Index values for a set of ten wetlands in north Mississippi were evaluated against relative disturbance rankings of study sites, based on local and landscapescale impacts from anthropogenic habitat modification and use (e.g., agricultural use, forest land cover, hydrologic and other on-site habitat modifications), the principal causes of habitat degradation in ecosystems worldwide. The adequacy of our four indices also was compared with that of the FQAI for the same set of wetlands. Of the indices evaluated, the one that correlated most closely with wetland disturbance rankings was that which incorporated the most information on relative importance of native and exotic plant species, in addition to wetland affinity: wherein WC is the Wetness Coefficient for each species present, based on wetland indicator status; S is total species richness for the site; f is the sum of frequencies of native species among all sample plots; and F is the sum of frequencies of all species among all sample plots. These results highlight the important effects attributable to exotic species dilution of native richness and have yielded a potentially useful criterion for evaluating ecological integrity of wetland ecosystems. Keywords: aquatic plants, biological indicators, ecological integrity, exotic species, native species, wetland indicator status, wetlands
Winter Cover Crop Management Systems Increase Annual Extraction Rates of Manure Nutrients in Swine Effluent Spray Field
Year: Authors: Rowe D.E., McLaughlin M.R., Brink G.
Swine effluent is repeatedly applied to the same fields via irrigation because the economics of transporting the effluent is prohibitive. The sustained safe use of a spray field is immediately linked to the rates of removal of potentially polluting nutrients. In the South researchers are determining the best winter cover crop and its management to use with bermudagrass summer crop to maximize winter and annual uptake of nutrients in harvested hay. Early studies indicated the value of bermudagrass as the summer perennial forage and annual ryegrass as the winter forage. Harvesting the annual ryegrass winter cover crop increases annual P uptake by about 30% over the summer harvests. Subsequent research shows that use of berseem clover, a winter annual, when harvested twice instead of once increased uptake of P, Zn, and Cu in the ranges of 20 to 60%. The winter cover crop species and its management have residual effects on productivity of the summer forage. Competition between winter and summer forages complicates agronomic recommendations for management of swine effluent spray field.
Runoff losses of Nitrogen and Phosphorus from a No-till Cotton Field Fertilized with Broiler Litter
Year: Authors: Adeli A., Rowe D.E., Tewolde H., Shankle M.W.
Broiler litter is rich in plant nutrients that increase cotton production, but surface application of broiler litter on no-till cotton allows nutrients to be transported from fields in surface runoff, while much of the ammonia-N volatilizes. Incorporation of broiler litter into the soil surface can reduce such problems, but has not been investigated for no-till cotton systems. A field experiment was conducted on an Atwood silt loam (fine-silty, mixed, thermic Typic Paleududalfs) soil at the Pontotoc Ridge-Flatwoods Branch Experiment Station in Pontotoc County, MS in 2004 to determine if surface incorporation of broiler litter applied to a no-till cotton influences the runoff loss of nutrients. The experimental design was a randomized complete block with 4 treatments replicated 3 times. Treatments included untreated control with and without surface incorporation and broiler litter applied at the rate of 8.2 Mg ha-1 with and without surface incorporation. Runoff volume increased by 30 % when litter was incorporated. Incorporation of broiler litter into soil surface decreased dissolved P and NH4-N and increased NO3-N concentrations of runoff water samples. Total suspended solids, total P and particulate P were greater for surface incorporation than non-incorporated treatments, indicating that greater soil loss resulted in greater amounts of particulate and total P being transported in runoff. Therefore, preliminary results suggest that incorporation of broiler litter into the soil surface of a no-till cotton field could be advantageous if erosion is controlled.
Soil Tillage Systems and Herbicide Leaching in Brazil.
Year: Authors: Cerdeira A.L., Dornelas-DeSouza M., Bolonhesi D., Queiroz S.N., Ferracini V.L., Ligo M.V., Pessoa M.Y., Smith, Jr. S.
The Guarany aquifer located in South America has a dimension of approximately 1,200,000 Km2 and spreads to areas of eight Brazilian states plus parts of Argentina, Uruguay and Paraguay. The region of Ribeirao Preto City, located in Southeast of Brazil, Sao Paulo State, is a sugarcane, soybean, peanuts, and corn producing area. This region is also an important recharge area to the aquifer. Intensive farming on the area has demanded constant use of herbicides and fertilizers. Triazine herbicides such as atrazine, ametryn, and simazine are used on the area and are known to have potential for groundwater contamination. Currently most of the sugar cane crop is mechanically harvested without burning. This practice allows the straw to decompose in soil, maintain a better soil structure, and interferes with the movement and leaching of solutes. It is a common practice to sow peanuts after sugarcane harvest using no-tillage or conventional planting systems. To evaluate the effects of herbicide leaching into groundwater during notillage planting of peanut after mechanically harvested sugarcane, a soil leaching study using soil columns has been conducted. The results showed a general trend of higher density and lower porosity in soils under no-tillage, mainly at the top layer. The Hydraulic Conductivity determined in soil columns was higher for soils under conventional system than no-tillage, 10.82 and 4.59 cm/h respectively, indicating higher leaching potential for conventional system. Keywords: Groundwater, Nonpoint Source Pollution, Hydrology, Agriculture, Solute Transport.
Factors Influencing Runoff of Pesticides from Warm Season Turfgrasses
Year: Authors: Ampim P., Massey J., Stewart B., Smith C., Johnson A., Armbrust K., Andrews A.
There is growing concern over the environmental fate of pesticides applied to turfgrasses. Of key interest is that pesticides used to maintain golf courses and home lawns will pollute drinking water sources and impact human health. In addition, there is the possibility that pesticide runoff could impact the ecology of surface waters and the health of wildlife. Understanding the fate of turf applied pesticides and predicting possible environmental concentrations requires knowledge of the factors affecting their movement or transport. This study was conducted using 2, 4-D herbicide (2, 4-dichlorophenoxy acetic acid), flutolanil fungicide (trifluoro-3`-isopropoxy-o-toluanilide) and chlorpyrifos insecticide (O, O-diethyl hexahydro-4, 7-methanoindene) applied at maximum label rates to two turfgrasses maintained as either golf course fairways or residential lawns. The turf species used were Tifway 419 bermuda grass (Cynodon dactylon [L] Pers. X Cynodon transvalensis Burtt-Davy) and Meyer zoysia grass (Zoysia japonica). The plots were 3.65 m x 9.14 m in size and sloped at 3 %. The plot arrangement is a split design. Simulated rainfall was applied to the plots to generate runoff within 24 hr of pesticide application. Runoff from the plots was collected at 5 minutes intervals. The targeted rainfall application rate was 2.5 cm hr-1. Average runoff rates for the three pesticides were 25% for 2,4-D herbicide, 2% for flutolanil fungicide, and 0.5% for chlorpyrifos insecticide. The runoff results correlated well with the soilwater distribution coefficients that were determined for the Brooksville silty clay soil (fine montmorillonitic, thermic Aquic Chromudert) present at the runoff site. Soil organic carbon adsorption coefficients were 73 ml/g for 2,4-D, 576 ml/g for flutolanil, and 3551 ml/g for chlorpyrifos, indicating weak adsorption potential for 2,4-D, moderate to strong adsorption for flutolanil, and high adsorption for chlorpyrifos. Runoff potentials for these compounds were anticipated to be indirectly correlated with the adsorption coefficients of the pesticides; the runoff data support this hypothesis. Maximum observed concentrations in turf runoff were 962 ppb for 2,4-D, 1336 ppb for flutolanil, and 23 ppb for chlorpyrifos. The maximum concentration observed in runoff is a function of wash-off potential, persistence, and application rate. Flutolanil had the highest application rate at 8.7 lb ai/A, chlorpyrifos was applied at 1 lb ai/A, and 2,4-D was applied at 0.24 lb ai/A. These edge of field concentrations exceed published aquatic toxicity threshold values for 2,4-D and chlorpyrifos. However, actual impacts on aquatic organisms would likely be greatly attenuated by dilution from runoff from non-treated areas.
Social Capital: A Unifying Framework for Understanding Conservation Decisions
Year: Authors: Steil K., Oldham J.L., Gill D.A.
Agricultural pollution is believed to be a leading contributor to nonpoint source pollution. Whereas most industrial polluters are subject to state and federal environmental regulations, historically, agriculture has been exempted. Most states depend on voluntary participation in technical assistance and educational programs to promote best management practices (BMP) adoption. The decision of agricultural producers to engage in BMPs is shaped by a number of forces. Research indicates that two of the most significant factors influencing the adoption of BMPs are farm size and education. However, social factors associated with the adoption of agricultural practices that improve water quality have received less attention. A notable exception is a 1998 survey of farm operators in the Mississippi Delta which highlighted the importance of institutional factors, such as the influence of information sources and attitudes toward government regulations, in the decision process. This poster presents a literature review using a social capital framework to better understand the interplay between social, economic, and environmental factors affecting adoption of new agricultural technology and best management practices. The trust, reciprocity, information, and cooperation associated with social networks create value, or social capital, in the norms, shared values, and behaviors that bind people and communities together and make cooperative action possible. Understanding environmental stewardship decisions within the context of a social capital framework can assist policy makers promote participation in technical assistance and educational programs.
Using Hatchery Waste By-Products as a Source of Lime and Nitrogen
Year: Authors: Lee J.A., Oldham L., Reid P., Cox M.
Currently, hatchery waste generated by Mississippi poultry integrators is processed and landfilled. Land application of the hatchery-origin material as a soil amendment on agricultural land may be an alternative to landfill disposal due to its calcium carbonate equivalent and nitrogen content. A greenhouse experiment to evaluate the effects of the by-product on soil pH and plant nutrient bioavailability was conducted at the Rodney Foil Plant Science Center at Mississippi State University using two soil series: Ruston (fine-loamy, siliceous, semiactive, thermic Typic Paleudult) and Urbo (fine, mixed, active, acid, thermic Vertic Epiaquept). Hydrated lime was used as a comparison liming material. The hatchery waste by-product was chemically analyzed to determine the calcium carbonate equivalency of 79.6% and nitrogen of 18 g kg-1. Soil samples were analyzed by the Mississippi State University Extension Service Soil Testing Laboratory for lime requirement: Ruston soil (pH 5.3), 1.5 tons 100% Calcium Carbonate Equivalent (CCE) per acre, and Urbo soil (pH 5.1) 4 tons 100% CCE per acre. Five rates of the hatchery by-product (1, 2, 3, 4, and 5 ton(s) acre-1 equivalent) were mixed with soil and distributed to 15 cm diameter pots using a Completely Randomized Block treatment design with four replications. Pots were watered and equilibrated 24 hours, then seeded with annual rye grass (Lolium multiflorum). Data detailing the effect of hatchery by-product applications on soil acidity amelioration and plant nutrient bioavailability will be presented.
Leaching of nitrogen, phosphorous, and potassium from sawdust amended with chicken litter
Year: Authors: Hatten N.R., Borazjani H., Diehl S.
A six month study evaluated composting effects on nitrogen (N), phosphorus (P), and potassium (K) leaching from hardwood and furniture sawdust amended with 20% and 30% chicken litter. Toxicity Characteristic Leaching Procedure (TCLP) was used to obtain leachates from substrates. Moisture was provided through precipitation, and the substrate was aerated once or twice per week, depending on the amount of rainfall. Samples were collected at 45 day intervals for analysis. A significant reduction in N and K concentrations occurred for all amended compost by day 180. Hardwood substrate matured quicker than furniture compost based on a radish seed germination test. Toxicity reduction occurred in every treatment by day 180. Chicken litter control showed the best overall weight loss; however, its toxicity levels were still much higher on day 180.
Accumulations of nutrients in corn soil as influenced by poultry litter application rate
Year: Authors: Gilfillen R.A., William W.T., Henderson H.
Poultry litter can be a valuable resource when applied at rates required by a given crop. However, nutrients being present in higher concentrations than needed, or not available when needed, are obvious concerns for producers when using poultry litter as a fertilizer. During 2001-03, silage corn plots were established under no-till and conventional till conditions with three fertility treatments superimposed over the tillage treatments. The fertility treatments were (1) ½ rate of poultry litter at N rate and ½ inorganic N, (2) poultry litter applied at the N rate, and (3) inorganic fertilizers. Soil samples were taken from 0-15 cm prior to planting, at mid-season, and at corn harvest. The harvest soil samples were analyzed for nutrient content and comparisons are as follows. Over the three year observation, very few differences were seen between tillage treatments. Interactions existed between tillage and fertility for available Mg and Cu, along with organic matter and CEC. Differences were observed between fertility treatments in the following measurements: water pH, available P, K, Zn and ortho-phosphate content. Water pH was greater in treatments receiving poultry litter than inorganic fertilizers alone. Available P and Zn were higher in treatment 2 than 3. Available K was higher in treatment 2 than either 1 or 3. Ortho-phosphate content was greater in treatment 2 than in 3. Indications are that poultry litter applied at the N rate resulted in excess levels of available P, K, Zn, and ortho-phosphate in comparison to the inorganic fertilizers.
Bermudagrass Production and Nutrient Uptake when Substituting Broiler Litter Nitrogen with Mineral Nitrogen
Year: Authors: Read J.J., Brink G.E., Oldham J.L., Kingery W.L.
Achieving adequate hay production from hybrid bermudagrass [Cynodon dactylon (L.) Pers.] when plant P nutrition is the basis for broiler litter application rates will require supplementation with mineral nitrogen (N) fertilizer. The objective of this research was to determine yield and uptake of N and P in hybrid ‘Coastal’ bermudagrass fertilized with different rates of broiler litter in combination with applications of ammonium nitrate (34-0-0). Plots (4 x 6 m) were established at Mize, MS in a pasture with 30+ year history of litter and soil test P (STP, by Mehlich III analysis) of about 409 kg P ha-1, and at Newton, MS in a pasture with no litter history and STP of about 52 kg P ha-1. Broiler litter rates of 0, 4.5, 8.9, 13.4, and 17.9 Mg ha-1 were obtained by monthly applications of 4.5 Mg ha -1 beginning in April, and these rates were supplemented, respectively, with 67 kg ha-1 mineral N (the highest rate beginning in April) in order to achieve 269, 202, 134, 67, and 0 kg N ha-1. Thus, the annual N requirement of bermudagrass of about 269 kg N ha-1 was first met with broiler litter and then with mineral N. Treatments, including an unfertilized ‘check’, were repeated on the same plot areas in 1999, 2000, and 2001. Because forage dry matter (DM) was consistently low in unfertilized bermudagrass, averaging 12% (Newton) and 55% (Mize) of the highest average yield, these data were often used for comparison only. When analysis of variance was conducted without the ‘check’ plots, treatment difference in forage dry matter (DM) and P uptake were significant at Newton (P<0.01), but not at Mize (P>0.50). A significant treatment by year interaction was detected for yield and P uptake at both sites, primarily because these traits were greater in 2001 than 1999 and 2000 due to increased rainfall. At Newton, fertilization with only mineral N led to 2.0-3.0 Mg ha-1 lower DM as compared to other treatments, and the 8.9 Mg litter + 134 kg N treatment appeared to maximize DM and nutrient uptake. At Mize, forage yield and P concentration =90% of maximum relative yield were obtained from 4.5 Mg + 202 kg N treatment. Results indicate broiler litter rates should not exceed 8.9 Mg ha-1 yr-1 and be supplemented with mineral N to meet the crop N requirement. Although pasture N fertilization is costly, the practice may minimize environmental impacts when litter nutrients, particularly P, are applied in excess of crop needs.
Applying poultry litter in the fall diminishes its fertilizer value
Year: Authors: Tewolde H., Sistani K.R., Rowe D.E., Adeli A., Johnson J.R.
Applying poultry litter in the fall to cotton and other row crops may be a practical option for farmers that have no time to manage litter application in the spring. However, whether fallapplied litter is as effective as spring-applied litter is not well investigated. On-farm research conducted at three locations in Mississippi indicated that applying litter in the fall may not be as effective as applying litter in the spring. Cotton responded very poorly to broiler litter in two of three years at Macon, MS where the litter was applied in the fall. Broiler litter applied in the fall at this location increased lint yield by only 62 lbs lint acre-1 ton-1 litter in 2003 and by 40 lint acre-1 ton-1 litter in 2004 compared with 230 lbs acre-1 ton-1 litter in 2002. The yield response to litter at two other locations in 2003 and 2004 where the litter was applied shortly before or after planting in the spring ranged between 121 and 161 lbs acre-1 ton-1 litter. These results suggest that there is substantial risk of mineralization and loss of mineralized litter-N before planting when litter is applied in the fall. We suspect leaching and denitrification as the primary causes of N loss when soil moisture and temperature conditions in the fall and winter after applying litter are ideal for the mineralization of litter-N.
Soil Nutrient Accumulation and Field Corn Yield as Influenced by Poultry Litter Application Rate
Year: Authors: William W.T., Gilfillen R.A., Sleugh B.B., Sistani K.R., Henderson H.D.
Previous research has indicated that broiler litter can increase field crop yields but may provide amounts of some nutrients in excess of crop needs, resulting in excessive soil accumulation. A field experiment was conducted from 2002-2004 to investigate the influence of broiler litter application rate on field corn grain yield and soil nutrient concentration. Broiler litter was applied at 0, 4.5, 9.0, and 13.5 Mg ha-1 and incorporated prior to crop establishment. An inorganic fertilizer treatment was included for comparison purposes. Soil samples were taken (0- 15 cm depth) prior to planting in 2003 and 2004 and analyzed for pH, organic matter content, available P, K, Cu, and Zn. Grain yield was taken at crop maturity. Broiler litter rates of = 9.0 Mg ha-1 were required to produce grain yield comparable to a standard inorganic fertilizer program. Application rates that produced grain yield equivalent to that of inorganic fertilizer simultaneously increased available P, K, and Cu in surface soil. Annual fertility amendments increased soil organic matter content by 4.5 g kg -1 and soil pH by 0.21 units. These results suggest that field corn producers wishing to utilize broiler litter as a nutrient source should consider a nutrient management program in which broiler litter rates of < 9.0 Mg ha-1 are supplemented with inorganic nitrogen.
Evaluation of an Advanced Waste Treatment System for Reduction of Malodorous Compounds from Swine Waste
Year: Authors: Loughrin J.H., Szogi A.A., Vanotti M.B.
Technologies are needed that reclaim nutrients, kill pathogens and reduce emission of ammonia and nuisance odors from animal waste. A full-scale system (4,360-pigs) was implemented as part of the Smithfield Foods/Premium Standard Farms/Frontline Farmers Agreement with the North Carolina Attorney General to develop technologies that accomplish these goals and offer alternatives to waste-treatment lagoons. The system increases the efficiency of liquid/solid separation by injection of polymer to increase solids flocculation. Ammonia emission is reduced by passing the liquid through modules with immobilized nitrifiers/denitrifiers. Subsequent alkaline treatment of the wastewater in a phosphorus module precipitates calcium phosphate and kills pathogens. Previous reports have shown that this system effectively reduces nutrients and pathogens of high strength wastewater. This report evaluates the system’s effectiveness for the remediation of malodorous compounds from waste. Preliminary headspace analyses showed that the levels of five key malodorous compounds (phenol, p-cresol, 4-ethylphenol, indole and skatole) were reduced by over 90% in treated water as compared to raw flushed manure. Subsequent solid phase extraction measured levels of volatile compounds at each stage of the treatment process in order to identify stages that reduce malodorous compounds and potential control points for the reduction of odors in the treatment system. Seventeen volatile compounds consisting of aromatics, hydrocarbons, and brominated aliphatics were identified from swine wastewater. As seen in headspace analyses, the levels of compounds with objectionable odors were reduced by an average of more than 90 percent during treatment: in effect, wastewater odor reduction was achieved during denitrification of the wastewater. Experimental results are discussed in relation to sampling methodology and wastewater treatment stage.
Iron Humate for Manure Treatment and Phosphorus Control on Small Dairy and Swine Farms
Year: Authors: Johnson V.B., Rehberg B.
Focus on animal waste treatment for phosphorus control has small farmers in a quandary. This presentation will focus on a system using Iron Humate, the co-product created during the treatment process of Potable water treatment plants. The costs and simplicity of this technology provides an alternative that can be employed by smaller (<500 Head) operations common in Mississippi. Sophisticated systems for manure dewatering and treatment involving centrifuges, screw presses, belt presses, dissolved air floatation units, and other devices common in municipal sludge dewatering are well beyond the capital, operation, and maintenance capabilities smaller enterprises. Further, the level of expertise required is not usually available in the workforce at hand, forcing the dairy or swine operator to do it themselves or go outside the normal workforce and hire more expensive employees with additional training and skills. These technologies appear out of the reach to all but the largest farms. One new technology holds promise for many operations. This technology uses Iron Humate and coagulants for nutrient removal from the waste stream as means for effectively binding and removing the phosphorus. This also provides a beneficial re-use of the Iron Humate co-product created during the water treatment process. The resultant iron humate/phosphate filtrate material may also be used as an excellent source of iron and Phosphorus for pasture fertilization. This alternative provides a low maintenance alternative for the smaller livestock operation and does not require the capital expense or operational expertise required with more sophisticated systems. The waste stream is filtered through the Iron Humate which effectively absorbs the nutrients from the waste stream while retaining solids for further treatment or disposal. Current data shows phosphorus removal efficiencies greater than ninety percent. Application technology for Dairy and Swine operations as well as parameters required by Water Utilities to incorporate this process into their system will be presented.
Manure Treatment Systems and Nutrient Control of Dairy Waste
Year: Authors: Johnson V.B.
Retrofitting municipal and industrial dewatering technology for dairy waste treatment has met with limited success. Many waste treatment systems use various components from different industries in an attempt to find an efficacious fit. Further employing conventional static separators designed to remove or reclaim fiber and bedding materials may not provide the nutrient removal efficiency required. Emerging technologies for animal waste treatment have promised innovative and brilliant systems, but they are untried and out of the economic reaches of many operations. These new systems require specialized operation and maintenance expertise not common in the workforce easily available to the Dairy or Swine operator. Recently a systems approach to dairy waste treatment has been introduced specifically suited to animal waste treatment and the livestock operation’s ability to operate and maintain equipment. Several systems are currently in use on Dairy and Swine facilities in the U.S. These systems employ either mechanical or passive fiber separation. Mechanical systems add components such as static screens, screw presses, sequential centrifuges and in some cases a dissolved air floatation unit for additional removal and nutrient recovery. Passive systems employ a geosynthetic material for nutrient removal and fiber recovery. Use of chemical precipitants (aluminum sulfate, ferric sulfate, ferrous sulfate) and polymeric flocculants improve removal efficiencies of phosphorus to >80% and are used in both systems. A brief overview of typical system design, nutrient removals and capital costs will be presented in a case study format for Dairy and Swine facilities currently utilizing these technologies.
The Effect of Further Hatchery Waste Processing on Soil Acidity Amelioration and Plant Response in Two Mississippi Soils
Year: Authors: Reid P., Lee J.A., Oldham L., Cox M.
Soil acidity decreases yields of hay, pastures, and row crops throughout Mississippi. Except for marl or chalk, Mississippi liming materials are imported which increases the cost of ameliorating soil acidity relative to neighboring states with native calcitic or dolomitic limestone quarries. Alternative liming materials may offer significant lower application costs. Crushed eggshells from poultry hatchery operations, largely composed of calcium, usually are landfilled in the south-central Mississippi poultry production cluster. This work evaluates the effectiveness of dry versus wet hatchery waste as soil liming materials. It is part of a larger effort examining agronomic efficacy and soil chemistry effects of hatchery waste in the state. Two greenhouse pot studies used Ruston soil (fine-loamy, siliceous, semiactive, thermic Typic Paleudult) and Urbo soil (fine, mixed, active, acid, thermic Vertic Epiaquept) soils collected from the surface 15 cm at mapped locations in Oktibbeha County, MS. Using standard soil testing procedures of the Mississippi State University Extension Service Soil Testing Laboratory, the lime requirement for the Ruston soil (pH 5.3) was 1.5 tons 100% Calcium Carbonate Equivalent (CCE) per acre, and 4 tons 100% CCE per acre for the Urbo soil (pH 5.1). One study examined the effect of application rates based on wet weight of the waste material; waste material was dried, ground, and sieved for the second study. Treatment design of each study was a Completely Randomized Block with four replications. Application rates of the material for both wet and dry studies were 1, 2, 3, 4, and 5 tons acre-1 with an assumed 75% CCE (actual analysis 79.8%). Hydrated lime treatments were used as controls. Soils were mixed with the various rates of material and distributed to 15 cm diameter pots. Pots were watered and equilibrated 24 hours, then seeded with annual rye grass (Lolium multiflorum). The effect of drying, crushing, and sieving the byproduct prior to soil application will be contrasted with applying wet, ‘as is’ material in this report. Changes in soil pH over incubation through 90 days, ryegrass germination rates, and plant growth responses will be reported.
Nutrient Uptake and Runoff from Alum-treated Broiler Litter Tall Fescue Plots
Year: Authors: Sistani K.R., Mays D.A., Dawkins R.A.
Land application of poultry litter as fertilizer may lead to impaired surface and ground water quality. An experiment was conducted at Crossville, AL to study the effects of alum [Al2 (SO4)3,14H2O] treatment of broiler litter on the yield and nutrient uptake of tall fescue (Festuca arundinaceae) and the nutrient content of runoff water exited from treated plots. Alum treatments had no effect on tall fescue dry matter yield, and the herbage nutrient concentrations were within acceptable limits. We noted significant reductions in the runoff concentrations of NH4-N (28.6 mg L-1 for untreated litter VS 15.0 mg L-1 for alum-treated litter), total P (11.5 mg L-1 VS 5.1 mg L-1), soluble reactive P (10.4 mg L-1 VS 4.7 mg L-1 ) , and particulate P (1.9 mg L- 1 VS 0.8 mg L-1 ). This practice should receive serious consideration as a method of reducing the adverse environmental impact of broiler chicken production when the litter is applied to pasture land.
Nutrient Uptake and Forage Quality of Sorghum-Sudangrass Under Different Poultry Litter Fertility Programs
Year: Authors: Sleugh B.B., Gilfillen R.A., William W.T., Henderson H.
More producers now use poultry litter as fertilizer because of increasing inorganic fertilizer cost. Poultry litter is often over-applied and may cause water pollution and soil nutrient imbalances. Our objective was to evaluate nutrient uptake of sorghum-sudangrass to determine its viability as a nutrient removal tool while providing adequate forage yield and quality. Treatments included: litter applied at recommended nitrogen (N) rate; recommended phosphorus (P) rate plus supplemental inorganic N; recommended P rate; and inorganic fertilizer. Samples were analyzed for acid detergent fiber (ADF), neutral detergent fiber (NDF), crude protein (CP), P, Cu, Zn, and Fe. The treatment by year interaction was significant for most variables analyzed so the data will be presented by year. All variables were affected by treatment but generally, P concentration increased from 2001 to 2003 with the largest increases in plots receiving inorganic fertilizer (30%) only and those receiving litter based on the P recommendation (31%). There was a 60% increase in Fe concentration in plots receiving litter at the recommended N rate. Our findings suggest that applying poultry litter at a lower rate can significantly reduce P and Fe concentration when compared to other treatments. When lower rates of poultry litter are applied based on P recommendation, supplemental inorganic N could be added to ensure adequate N nutrition. In our study, supplementing inorganic N on plots receiving low rates of litter produced forage of similar quality to inorganic fertilizer in 2 of 3 years.
Addressing the non-traditional nutrient management education needs of Mississippi poultry producers: History, action, and future
Year: Authors: Oldham J.L., Lee J.A., Chamblee T.N.
Poultry production, the largest grossing agricultural enterprise in Mississippi, is concentrated in the south central region of the state. The industry cluster increases concerns about nonpoint source pollution and water resource quality in the region. Site specific nutrient management plans are required by the Mississippi Department of Environmental Quality for poultry farms that have changed production levels since 1994, or are classified as Concentrated Animal Feeding Operations (CAFO’s) according to Environmental Protection Agency regulations. In recent years, Mississippi State University Extension Service (MSU-ES) and Experiment Station personnel have worked closely with all segments of the industry and other agencies to expand the research base and to provide training in nutrient management. Reorganization of MSU-ES in 2002 addressed the need for more non-traditional education programs in environmental issues in general, and nutrient management in particular. Mississippi based research and outreach programs were reviewed at a symposium in December, 2003. Facilitated discussion among symposium attendees focused the perceived strengths and weaknesses of the effort, and offered suggestions for improvement. The Environment/Nutrient Management Program Priority Group was organized to plan and implement programming efforts using multiple disciplines and university units. An Extension area agent specialty was defined, advertised, hired, and placed in the poultry region to provide educational programs and serve as a resource. Recent changes in state CAFO permit requirements (2004) further increased the educational needs of poultry producers in nutrient management, record keeping, and other management skills.
Solving the Chicken Litter Problem: Development of Novel Practices for Chicken Litter Management and Disposal
Year: Authors: Whitely N.R., Ozoa R., Wu C., Chen D., Pan W.
Studies have shown that the over usage of chicken litter on agricultural land can lead to air and water pollution. The EPA is beginning to limit litter spreading for fertilization based on the geography, soil, and proximity of the land to bodies of water. The decreasing volume of chicken litter spread as a fertilizer will urge the scientific community to develop novel uses or disposal methods to remedy the current problem. Chicken litter has much potential at providing energy and materials. Much research has shown that chicken litter having calorific values equivalent to low rank coals (on the order of 5000 BTU/lb) can be combusted either has the sole fuel or as a co-firing agent to coal to generate energy. Upon pyrolysis, chicken litter primarily yields active carbon useful for generating numerous other materials; however, gas and liquid fractions collected can be used for energy and chemicals. In this current study, the evolved gases of chicken litter and chicken litter/coal blends are investigated using thermogravimetric-mass spectrometry (TG-MS), thermogravimentric-Fouriertransform infrared spectroscopy (TG-FTIR), and pyrolysis gas chromatography mass spectrometry (GC/MS). Both the combustion and pyrolysis mechanisms are studied. Devising a decomposition mechanism for the chicken litter into its evolved gases, especially ammonia and sulfur compounds, is of great importance. Understanding the emissions and decomposition characteristics will serve to optimize the combustion and pyrolysis of chicken litter.
Mass Balance Studies of Pesticides in Agricultural Watersheds: Importance of Agricultural Deposition
Year: Authors: Capel P.D., Ohrt A.W., Coupe R.H.
The U.S. Geological Survey’s National Water-Quality Assessment Program (NAWQA) is conducting a number of studies in small agricultural watersheds with the lofty goal of constructing annual mass budgets for water, nutrients and selected pesticides. One of these studies is starting in the Bogue Phalia in Mississippi in 2005. After a pesticide is applied, it can undergo transformation in the soil, be taken up by the plant, be stored in the field, or be transported to the broader environment, such as the atmosphere, surface water or ground water. When a pesticide enters the atmosphere, it will eventually be reintroduced to the terrestrial system either by wet (e.g., rain, snow) or dry (e.g., dry fall, air-soil exchange) deposition, if it does not undergo reaction in the air. Atmospheric deposition is then a part of a pesticide’s overall mass budget. These USGS studies have measured the concentration of pesticides in the rain and air to estimate the magnitude of this term in the mass budget. In most locations, the most frequently detected pesticides in air and rain were the herbicides acetochlor, atrazine, and metolachlor. The seasonal concentration patterns of the atmospheric pesticides mimicked the agriculture activities of the area. The dry atmospheric flux was calculated based on the concentrations of weekly integrated air samples and modeled aerosol deposition velocities. The wet atmospheric flux of pesticides was calculated based on the concentrations of weekly integrated rain samples and the volume of rain. The rain data, together with companion studies of the same pesticides in streams, were used to compare the relative importance of atmospheric deposition to surface runoff. The load of pesticides deposited by rain to each watershed was compared to the load of pesticide in surface runoff (as quantified by the stream load) from the watersheds in this study and from data available from the literature for other watersheds. The annual load of any given pesticides deposited by rain was generally equal to or greater than its annual load in runoff. Even though the atmosphere is important for moving many pesticides through the environment, atmospheric deposition is still a minor term in their overall mass budget.
CYP1B-Gene Expression in Channel Catfish as a Biomarker for Sediment Contaminant Exposure
Year: Authors: Willett K., Ganesan S.
Sediments in some Mississippi rivers and lakes contain significant concentrations of environmental contaminants including pesticides and industrial by-products. Our previous analyses of sediments collected from three Mississippi Delta waterways (Lake Roebuck, Bee Lake and Sunflower River), suggested that polycyclic aromatic hydrocarbon (PAH) and organochlorine pesticides were detectable and highest at Lake Roebuck. We hypothesized that quantitating induction of CYP1B mRNA in catfish could potentially be a useful biomarker of exposure to these persistent contaminants. Specifically, we use primary cultured channel catfish liver hepatocytes and gill cells to determine the inducibility and/or inhibition of CYP1B. When cells were exposed to BaP concentrations (5x10-9 to 5x10-5 M) CYP1B was significantly (p< 0.01) induced in gill cells compared to DMSO treated control cells. Furthermore the CYP1B message was inducible by BaP in a dose-dependent manner. In contrast to the primary cultured gill cells, there was no significant CYP1B induction in liver hepatocytes. Ongoing studies are investigating the tissue specific effects of other contaminants including PCB 77, PCB 126, PCB 153, p,p’-DDT, and TCDD. These results will ultimately help characterize the utility of CYP1B as a marker of environmental contamination and the physiological significance of CYP1B in fish.
Project Description for the Regional Assessment of Trends in Nutrient and Sediment Concentrations and Loads in Major River Basins, South-Central Uni
Year: Authors: Rebich R.A., Coupe R.H.
The U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Program is conducting regional assessments of water-quality conditions and trends in 16 principal aquifers and eight major river basins (Hamilton and others, 2005). These assessments build on the NAWQA studies conducted from 1991 to 2001 in 51 river basins (fig. 1). NAWQA studies were designed to describe how natural features, land use, and human activities interact with and affect ground- and surface-water quality and aquatic communities. The regional assessments began in 2004 and will continue with findings and final publications scheduled to be available in 2007. The intent of these assessments is to summarize water-quality conditions in a regional context. The regional assessments of the eight major river basins (MRB) (fig. 1) will focus on chemicals in water and other water-quality issues relevant to surface waters in each region (Hamilton and others, 2005). In general, each MRB regional assessment will address trends in nutrients and sediment, pesticides, and biological-response data (chlorophyll, algae). The study area for each MRB regional assessment comprises more than one NAWQA study unit, and data used for trend testing will include data from NAWQA studies supplemented with data from other USGS studies, as well as available data collected by other agencies. In addition, trend tests will be coordinated to document temporal changes and spatial differences for a particular water-quality constituent, not only within a particular MRB study area, but also among study areas nationwide. The USGS Mississippi Water Science Center will complete an assessment of trends in nutrient and suspended-sediment concentrations and loads for rivers in the study area of the south-central United States, which is defined as the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf Region in figure 1. Several reports describe trends in nutrient and sediment data for this region. For example, studies by Van Metre and Reutter (1995), Demcheck and others (2004), Davis and Bell (1998), and Coupe (2002) document loads and trends in concentrations and loads of nutrients and/or sediments for statewide assessments or for selected river basins included in this region. National studies, such as work by Mueller and others (1995), include assessments of nutrient data from both ground-water wells and surface-water data-collection sites within this region. Studies summarized by Goolsby and Battaglin (2000), Meade (1995), and Turner and Rabalais (2004) assess nutrient concentrations and loads delivered by the Mississippi River Basin to the Gulf of Mexico; although these studies include data and results from this particular region, most of their focus is on the Upper Mississippi River Basin upstream of this region. The U.S. Environmental Protection Agency recently released results from its Nutrient Pilot Study, which included an assessment of nutrient concentration and loads from coastal or near-coastal waters draining into the northern Gulf of Mexico from Louisiana, Mississippi, and Alabama (U.S. Environmental Protection Agency, 2004). Therefore, this assessment is unique and timely in that it primarily will be focused on the entire Lower Mississippi, Arkansas-White-Red, Texas- Gulf Region, not just portions of the region. The water-quality constituents included in this assessment are dissolved ammonia, total ammonia plus organic nitrogen, nitrite plus nitrate, dissolved orthophosphate, total phosphorus, suspended sediment, and total suspended solids. Loads will be calculated, and both temporal and spatial trends for constituent concentrations and loads will be investigated. Trends in sources of nutrients (point and nonpoint) and sediment will be used to explain trends in the surface-water data that are identified. This assessment will help resource managers understand changes in concentrations and loads of nutrients and sediment entering the northwestern Gulf of Mexico from the study area. This paper presents descriptions of the study area, data sources, site selection, and methods of analysis to be used in the regional assessment of trends in nutrient and sediment data from rivers in the south-central United States.
Usage Survey of Mississippi’s Coastal Recreational Beaches
Year: Authors: Goff S.
develop a risk-based beach monitoring, notification and implementation process. The Mississippi Department of Environmental Quality’s goal in this process is to evaluate usage of Mississippi’s coastal recreation waters adjacent to the beaches and classify those waters based upon the potential risk to public health presented by pathogens and the use of the water. MDEQ identified twenty-two beach segments and similar points of access that are used by the public for swimming, bathing, surfing, or similar water contact activities. As growing numbers of people move to, or visit, Mississippi coastal areas and pollution threatens the waters in which people swim and play, there exists a risk of illness from exposure to waterborne pathogens. The frequency of use, and thus the potential exposure to pathogens, can be measured by determining how many people use the beach. Mississippi does not maintain historical detailed records of the number of people using its beaches. Therefore, the task or purpose of the Usage Survey of Mississippi’s Coastal Recreational Beaches was to develop a methodology and implement a process for determining frequency of public use. The months of May through October are the primary recreational season in Mississippi. Therefore, to determine maximum exposure, the twenty-two beach segments were surveyed during the three major holiday weekends (Memorial, Independence, Labor) plus one non-holiday weekend and three week days for a total of five data collection sets. To ensure data quality and consistency, a standardized survey instrument was used, the same survey group collected data on the same beaches through out the five survey periods, and surveys were conducted during the hours of 11:00 a.m. and 4:00 p.m. on the designated dates. Results of this survey will be used to assist Mississippi’s effort to manage a beach specific monitoring and notification program consistent with the requirements of the BEACH Act of 2000 and the Environmental Protection Agency’s performance criteria guidance.
Plants of the Coldwsater River, Mississippi, USA: Community records along the hydrologic gradient in the loess hills
Year: Authors: Cooper C.M., Huneycutt M.B., Testa, III S.
The natural channel of the upper Coldwater River, which drains a large (565 km<sup>2</sup>) multiuse catchment in the loess hills of Mississippi upstream of Arkabutla Reservoir, has been predominantly unimpacted by channel modifications or recent large-scale land clearing. The river is generally bordered by floodplain forest in various stages of growth, and streamfloodplain interaction occurs frequently. Currently, however, pervasive residential sprawl from the highly urbanized region near Memphis, Tennessee, is altering land use and eventually may alter significantly the hydrology, floodplain land-use, and biological communities occurring along this natural resource. To document existing conditions, a study of plant communities at eight locations along this river reach was conducted with recurring visits to sixteen 100m transects over a period of one year. A total of 294 species from 86 families were recorded. Greatest community richness was observed at the most upstream location with 165 plant species in 111 genera representing 59 plant families. Lowest richness (84 species) occurred at the mid-reach location. The most commonly encountered species were Lonicera japonica Thunb. (Japanese honeysuckle), Impatiens capensis Meerb. (jewelweed), Fraxinus americana L. (American ash) and Sambucus nigra L. (elderberry). Seventeen species were collected at all eight locations while 103 species were recorded at single locations only. No records of federally-listed threatened or endangered species were made, but observations were made for Platanthera flava (L.) Lindl. (the palegreen orchid) which is listed as endangered, threatened or of special concern in sixteen states. Our observations also included 45 species considered to be obligate inhabitants of wetlands, including Chelone glabra L. (white turtlehead). Two species [Carex pensylvanica Lam., pensylvanica sedge; and Lactuca biennis (Moench), tall blue lettuce] are potentially herein reported from the state for the first time. The upper reach of the Coldwater River is the only major hill land drainage in the Yazoo Basin which is unchannelized. Its richness of flora is reflective of its value as natural habitat.
Spatial Modeling of Soil Hydraulic Properties
Year: Authors: Ampim P., Johnson A.B., Massey J.H., Tsegaye T.
Interest in ground water research has provided researchers the opportunity to develop models that describe water and solute transport in variably saturated soils. Generally, unsaturated soil hydrologic models are based on numerical solutions of the Richard’s equation. The key parameters needed for solving the equation are water retention values, 0(h), and hydraulic conductivity functions, K(h). Further, hydrological processes vary in space. Knowledge of spatial heterogeneity of soil hydraulic properties is essential in quantifying solute and water transport processes from a plot-scale to a regional-scale. Direct measmements of 0(h) and K(h) are time-consuming and expensive (Arya and Paris, 1981; Saxton et aI., 1986; Schuh and Bauder, 1986; Wosten and van Genuchten, 1988; Kem, 1995; Scott, 2000 and Comelis et al. 2001). Their measurements may be cost prohibitive in the short-term for large areas (AIya and Paris, 1981), and are not practical for remote sensing investigations (Saxton et al., 1986). The lack of knowledge of these parameters largely affects our ability to address hydrologic problems when modeling water and solute transport in large and complex watersheds. A progressively more popular altemative to direct measurement of soil hydraulic properties involves the use of pedotransfer functions (PTFs) (Wosten and van Genuchten, 1988, Comelis et al. 2001, Zhu and Mohanty, 2002). In this research, we used PTFs to predict soil hydraulic properties for Memphis silt loam (fine silty, mixed, thermic, Typic Hapludalf). We further attempted to quantify spatial variability of these parameters and determined their functional relationships.
Use of Mississippi River Alluvial Aquifer Decline Rates for Allocation of EQIP Funds
Year: Authors: Lamastus-Stanford F.E., Pennington D.A.
The Farm Security and Rural Investment Act of 2002 reinstated the Environmental Quality Incentives Program (EQIP) to provide a conservation programs that promote agricultural production and environmental quality as hmUlonious goals. EQIP provides financial and technical assistance to producers who implement stmchlral and management conservation practices on agricultural land. The Mississippi Natural Resources Conservation Service (NRCS) identifies resource concerns and assessments that determline the focus of EQIP funds allocated to the state. In 2003 $11 million was allocated to Mississippi for conservation practices and an additional $1.1 million was allocated for the specific concern of groumdwater conservation. The water quantity resource concem is concentrated primarily in the north and central portion of the Mississippi Delta. To allocate the $1.1 specifically for water quantity conservation, certain areas were targeted based on the decline rate of the Mississippi River Valley Alluvial Aquifer (MRVA), which ranged from 0.13 ft to 0.88 ft loss per year.
Shallow Groundwater Dynamics in the Root Zone of a Cypress Wetland
Year: Authors: Laine B., Davidson G., Rice S.
The hydrology of the root zone in a forested wetland is being studied as part of a larger investigation of the hydrologic controls on wetland tree growth. Previous studies have shown that bald cypress trees (Taxodium distichum) undergo accelerated growth during years of high precipitation, including trees growing in saturated sediments where water should not be a growth-limiting factor. The primary cause of growth may be a precipitation induced influx of nutrients into the wetland or alteration of root-zone chemistry that enhances nutrient uptake.
Runoff Quality in Bermudagrass Plots Treated with Poultry Litter
Year: Authors: Johnson A.B., Jordan M.O., Rowe D., Tsegaye T.
The overall objective of this study was to quantify runoff volumes, concentrations ofN03-N, P04-P, K, Cu, Fe and Zn, and near-surface hydrology of bermudagrass plots treated with poultry litter under simulated rainfall. Pouluy litter with application rates of 0, 4.48,8.96,17.92 and 35.84 Mg ha-l was applied to micro-plots (1.75 x 2 111) on a 5% slope. The soil used in this study was a loessial Memphis silt loam (finesilty, mixed, thermic Typic Hapludalf). Rainfall simulator was used to produce two runoff events immediately and 1.55 h after poultry litter application. Soil profile water content increased with rainfall application. Cumulative runoff volumes for the 0,4.48,8.96, 17.92 and 35.84 Mg ha-l plots for the first rainfall event were 114.6, 84.3, 102.3, 155.4 and 88.9 L, respectively. During the second rainfall event, cumulative runoff volumes were 116.8, 106.9, 121.1, 167.3, and 130.7 L, respectively. Flow-weighted mean concentrations of N03-N, P04-P and K increased with litter application rate, however, P04-P concentration in the 8.96 Mg ha-l treatment was significantly smaller (19.68 mg L-I) than the 4.48 Mg ha-1 treatment (24.12 mg L,I) in the first rainfall event (p = 0.05). Nitrate-nitrogen concentrations in the 17.92 and 35.84 Mg ha-1 treatments were 55 and 112 times higher than the 4.48 Mg ha- 1 treatment. Approximately 13, 8.2,6.6 and 2.6% of soluble P was measured from runoff of the treated plots. Potassium concentration increased hyperbolically with increased poulfIy litter rates. In all treated plots, copper, iron and zinc concentrations were far below 0.001 mg L,l for the two rainfall events.
Characterizing Soil Hydraulic Properties in an Agro-Forestry Ecosystem
Year: Authors: Johnson A.B., Burks R.D., Tsegaye T., Ampim P.
Land use impacts on soil quality may be characterized by changes in soil hydraulic propelties. These properties directly influence infiltration as well as runoff and erosion_ Soils in the major land resource area, the Southem Mississippi Valley Silty Uplands (MLRA 134), have high erosion potential and land use practices affect soil loss. We measured hydraulic propelties of the dominant soil (Memphis silt loam) in MLRA 134 on adjacent mixed forest and pasture sites at six locations each in the Rodney Lake sub-basin of the Coles Creek watershed. The forest and pasture have been in existence for 100 and 30 years, respectively. Unconfined infiltration measmements were carried out in a range of descending tensions, 15, 10,6,3 cm of water, using 20 em disc tension infiltrometers. The Wooding’s model for steady state flow was used to estimate soil hydraulic conductivity, K(h). Soil cores were also extracted from the 0-15 and 15-30 depths to detelmine bulk density (Pb). The WP4 PotentiaMeter® was used to measure soil water retention values, 6(h), at the two soil depths and the van Genuchten-Maulem model was fitted to the experimental data using the optimization computer code, RETC. Results from this study showed significantly higher K(h) in the forest than the pasture for both experimental and fitted data (P<0.05). Water content from 0 to -33 kPa was significantly higher in the forest than the pasture, however, water retention in the forest was significantly higher at all water potentials at the 30-cm depth (P<0.05). The van Gelluchten-Maulem model showed a good fit to the experimental water retention data for both land use with root-mean-squares errors (nllse) of 0.0201 and 0.0249 in the forest at the 0-15 cm and 15-30 cm soil depths, respectively. Respective rmse for the pasture for the 0-15 cm and 15-30 em soil depths were 0.0464 and 0.0357.
Analysis of Freshwater Sand-Dwelling Chironomid Larvae in Disturbed and Relatively Undisturbed Blackwater Streams
Year: Authors: Fitch R.C., Beckett D.C.
Freshwater sand-dwelling chironomid larvae were studied in the summer of 2002 in six blackwater streams in Southem Mississippi. Three of the streams were in relatively undisturbed habitats and the other three streams were in disturbed habitats affected by either non-point source pollution, point source pollution, or both. Sand core samples were taken randomly within three sites per stream (five samples per site; fifteen samples total per stream), and chironomid larvae were identified to the lowest possible taxon. Rheosmitia sp. composed 20 - 80% of the larval chironomid population in the undisturbed streams, whereas the three disturbed streams had three different dominant taxa (i.e., Polypedilum scalaemum group, Tanytarsus sp. P, and Dicrotendipes sp.) and low percentages of Rheosmittia sp. Taxon richness, total number of chironomids, and species diversities were variable among the streams. However, polar ordination based on percentage similarity showed that the three disturbed streams clustered together, whereas the three relatively undisturbed streams formed a cluster distant from that of the disturbed streams. This study indicates that Rheosmittia dominates sandy substrates in blackwater streams that are relatively unpolluted. Furthermore, freshwater sand-dwelling chironomids can serve as indicators of ecological disturbance.
Status of Microbial Source Tracking in the North America
Year: Authors: Ellender R.D., Wang S.
In the United States and Canada, microbial source tracking is being investigated and used to identify source(s) of fecal pollution of water. Several events of the last year highlighted the advantages and present limitations of this field of research. Of importance to our state are the results and observations obtained during the first national investigation of present-day MST methods and target organisms. This study, conducted by the Southern California Coastal Water Research Project Authority, cataloged and compared the list of methods under consideration, compared similarities and differences between phenotypic and genotypic procedures, discussed the value of library vs. non-library based methods, evaluated different microbial targets (fecal coliforms, Escherichia coli, Enterococcus sp., Bacteroides, human, animal and bacterial viruses), and conducted a blind sample investigation in research laboratories in the United States. A United States Geological Survey investigation of the reliability of library-based source tracking results with Escherichia coli as the reference organism, was conducted by a team of researchers led by Don Stoeckel of the USGS, Ohio District. Investigators created a library of isolates from 9 different animals and compared blind and replicate sample isolates to this library. Data was examined for reproducibility, accuracy and robustness. Data was also examined to assist in the identify of methods that could be used in a specific location, to examine the method in a defined setling, or to understand how the method(s) would address a local issue(s). In the summer of 2003, a series of MST presentations at the biannual meeting of the US EPA Gulf of Mexico Program summarized the state of the art of MST research in the southeastern states. These presentations focused on new methods and approaches to MST and included discussions on the use of fluorescent whiting agents as targets of source tracking, the reliability of microbial source assignment using rep-PCR methods, targeted sampling using enterococci, commercial applications of MST, the implication of E. coli diversity for MST success and future prospects for MST research. This presentation will summarize these recent collaborations and discuss/suggest new or modified approaches in the search for reliable and valid methods of microbial source tracking.
Mississippi Embayment National Water-Quality Assessment - Cycle II: the Second Decade
Year: Authors: Smoot J.L., Coupe R.H.
In 2001, the second decade of the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program began. The program has been redesigned, and the second decade is referred to as Cycle II. The number of study units has been reduced from 60 to 42, and each study unit will be revisited in three groups of 14 on a rotational schedule. In 2004, the Mississippi Embayment NAWQA will begin its second decade of the NAWQA Program. Similar to Cycle I, each group will be intensively studied for three years, followed by six years of low-intensity assessment. The primary emphasis of Cycle II (2001 - 2011) is to assess long-tenn trends in water quality and to improve our understanding of the factors and processes that govern water quality. An additional emphasis is to fill critical gaps remaining in the status assessment, the main focus of Cycle I (1991 - 2001).
Invasive Aquatic Plants: A Threat to Mississippi Water Resources
Year: Authors: Madsen J.D.
Invasive aquatic plants are an ever-growing nuisance to water resources in Mississippi and the rest of the United States. These plants are generally introduced from other parts of the world, some for beneficial or horticultural uses. Once introduced, they can interfere with navigation, impede water flow, increase flood risk, reduce hydropower generation, and increase evapotranspirational losses from surface waters. Invasive species also pose direct threats to ecosystems processes and biodiversity. Although there are at least twenty different species of nonnative plants currently in Mississippi, with another eight perched on our doorstep, four species cause the bulk of nuisance problems in large surface waters: Eurasian watermilfoil (Myriophyllum spicatum), hydrilla (Hydril/a verticillata), waterhyacinth (Eichhornia crassipes), and water primrose (Ludwigia hexapetala). One additional species (giant salvinia (Salvinia molesta)) is a source of significant national concem. I will discuss general modes of introduction to the United States, dispersal to water resources, spread tluoughout a water resource once a plant is introduced to the system, and effects of large stands on water resource quality. General management approaches include prevention of infestation, and biological, chemical, mechanical, and physical control techniques of plant infestations. While many regulatory agencies oppose management for fear of potential adverse effects of the management techniques, in general the failure to prevent widespread growth of these species causes more hann to the resource than effective management.
Chemical Mixtures (Phase I): Consequences of WNV Eradication on the Amphipod Hyalella azteca
Year: Authors: Weston J., Slattery M.
Outbreaks of West Nile Virus (WNV) throughout the United States, and particularly in the Mississippi Valley States, have spurred plans to control the mosquito vector Culex spp. Chemical agents commonly used to control mosquito vectors are nonspecies specific pesticides that may potentially interact with non-target aquatic organisms, These compounds enter the aquatic enviromnent via direct or indirect routes eventually becoming part of water and sediment matrices. Individually or as mixtures with other co-occurring persistent or transient anthropogenic compounds, such as agricultural pesticides, these mosquitocides can potentially degrade the water quality and aquatic habitat of non-target aquatic organisms. Our group will present preliminary findings (Phase I) which are part of a multiyear study evaluating the co-occurrence and ecotoxicity of vector eradication compounds individually and in mixtures with agricultural pesticides. Currently, our work has focused on methoprelle, the active ingredient of Altosid™, a commonly used mosquito larvicide and its ecotoxicological effects on Hyalella azteca, a common freshwater amphipod and an important trophic link in aquatic ecosystems. This preliminary work, and information from the literature, was necessary to establish NOEC values for lllixture studies which are under development.
AGNPS Runoff Model: Geospatial Applications in the Upper Pearl River Bsin
Year: Authors: Tagert M.L., Shaw D.R., Massey J.H., Bingner R.L., Smith M.C.
The Upper Pearl River Basin (UPRB) drains into the Ross Barnett Reservoir, which is the largest of Mississippi’s three surface drinking water sources and supplies approximately 90% of the City of Jackson’s drinking water. Thus, the UPRB is an area of particular interest with respect to water quality and the establishment of Total Maximum Daily Loads (TMDLs). The USDA Agricultural Nonpoint Source (AGNPS) runoff pollution model, in combination with geographical information systems and remote sensing, is being used to predict water, sediment, and pesticide nonpoint source runoff in the UPRB. GIS software was used to process a digital soils layer, digital elevation models (OEM), digital land cover from Landsat satellite imagery, and other inputs to the AGNPS model. The digital soils information was obtained from the USDANRCS State Soil Geographic Database (STATSGO) at a scale of 1:250,000, and the OEMs are from the USGS National Elevation Dataset (NED). The TopAGNPS module of AGNPS, using the OEM as the main input, performed a topographic evaluation of the watershed as well as drainage area identification, synthetic channel networks, watershed segmentation, and subcatchment parameters. AGNPS model predictions for sediment and pesticide runoff in a Mississippi watershed are being compared to water and sediment samples taken at seven USGS-gauged locations within the watershed. Samples were collected weekly from May-August 2002 and monthly thereafter through May 2003. The samples were analyzed for fifteen different pesticides using a multiresidue method. Fluometuron and diuron were analyzed by high performance liqUid chromatography - ultraviolet (HPLC-UV), while tebuthiuron, simazine, atrazine, cyanazine, metribuzin, alachlor, metolachlor, pendimethalin, p,p’-DDE, norflurazon, and hexazinone were analyzed by gas chromatography - mass spectrometry (GCMS). Triclopyr and 2,4-0 were derivatized and then analyzed by GCMS. Metolachlor was detected in 47 out of 77 samples, followed by tebuthiuron with 45 detections and atrazine with 35 detections. Hexazinone was also frequently detected. The highest concentrations detected were 1.05 ppb for 2,4-0, followed by 0.67 ppb for triclopyr and 0.62 ppb for diuron. The detected concentrations were all below current lifetime health advisory levels (HAL) established by the EPA for each compound. The pesticide concentration and water flow measurements are being used to estimate pesticide loads as a function of land use in the UPRB. In turn, these results are being compared with pesticide loads predicted by AGNPS based on remotely sensed land use patterns.
The Flux of Herbicides in the Yazoo River Basin, Mississippi, 1996-97
Year: Authors: Welch H.L., Pell A.B., Coupe R.H.
The purpose of this study was to characterize the occurrence and to document the flux of selected herbicides in five rivers of the Yazoo River Basin during 1996 and 1997. From January 1996 through December 1997 a total of232 water samples were collected from five rivers in the Yazoo River Basin: the Bogue Phalia, the Big Sunflower River, the Skuna River, Steele Bayou, and the Yazoo River. The number of samples collected from the rivers ranged from 21 for the Skuna River to 62 for the Bogue Phalia.
Coastal Development and Water Quality: Assessing the Health of Mississippi’s Estuarine Waters
Year: Authors: Trigg C., Perry H.
During 1968/69 a large-scale study was conducted to provide baseline data on the hydrological and biological characteristics of coastal waters ofthe Mississippi Sound (Gulf of Mexico Estuarine Inventory and Study, Mississippi). In 2000/01 forty-two of the original 1968/69 stations were revisited and water and fauna were sampled using protocols developed during the earlier study. Data fl.-om the two studies were used to assess changes in water quality and to evaluate the environmental health of coastal waters. Monthly samples were taken (May through April) in the Pascagoula, Biloxi, Bay St Louis, and Pearl River estuaries at five salinity zones. Hydrological parameters measured at each site were temperature, salinity, and dissolved oxygen. Ammonia, nitrite, nitrate, orthophosphate, and total phosphate concentrations in surface and bottom water samples were analyzed at the Gulf Coast Research Laboratory. Water quality parameters were evaluated by study, estuary, and salinity zone. Salinities were significantly higher at most stations in 1968/69 than in 2000/01 and in both studies salinities were generally lowest in the westem Sound. Nitrate and nitrite concentrations were significantly higher while total phosphate and orthophosphate levels were lower in 2000/01 when compared to the earlier study. In 2000/01, salinity, pH, and dissolved oxygen levels increased and nitrate and nitrite levels decreased from inshore to offshore stations. Increased nitrogen loading is apparent and related to industrialization and rapid population growth in south Mississippi. Observed decreases in levels of phosphate may be attributed to the ban of these compounds in detergents. Data from these and other studies will be used to develop numeric water quality criteria that can be incorporated into State water quality standards.
The Under Lying Link Between Residential Storm Water Management Design and Development by a Managed Body of Water
Year: Authors: Verseman R., Sobley J., Bailey M., Murdock J.
This study will focus on a potential development in Smith County, Mississippi. The site is located in the Bienville National Forest, where a preliminaly master plan for a 900 acre recreational lake has been designed. The lake will offer features that include a high and low impact development types. The activities associated with the high impact include a conference center, traditional and RV camping, picnicking, small cabins and lodging, and a marina. The low impact activities include fishing, boating, swimming, biking, hiking, horseback riding, and primitive camping.
Assessment of Bio-Contaminants in the Porter Creek Basin of the Homochitto National Forest
Year: Authors: Mason S., Frymire W., Boll C., Johnson A.B., Price C.S.
Total colifolm and/or Escherichia coli (E. Coli) contamination of surface water is often attributed to loading of fecal material from agricultural, urban and residential areas or warm-blooded wildlife. The Homochitto Ranger District of the US Forest Service in southwest Mississippi is developing a 1000-acre lake (Okhissa Lake) in the Porter Creek sub-basin. The lake is being created by damming Porter Creek, which flows northh to the Homochitto River. This lake will be used mainly for recreation and is projected to receive 235,000 visitors annually. Clean, high quality water is necessary to support this use. Private residences are located along roads in the headwaters of the sub-basin. Public sewage treatment is not available and many of the residences have no or ineffective septic systems. To evaluate the potential effects of the current residential development with respect to State and the US Environmental Protection Agency water quality standards for coliform bacteria and E. coli, we embarked on a monitoring program prior to damming of Porter Creek. Ten monitoring stations were established within the P01ier Creek sub-basin where grab water samples were collected weekly in pre-sterilized bottles. Samples were then analyzed for total coliform and E. coli using colilert® substrates. Samples were emnnerated by the absence or presence in Quanti-TrayTM cells and the data expressed as most probable number (MPN) per 100 mL. To determine saturated, Ksat , and unsaturated hydraulic, K(h), conductivities, double ring and tension infiltrometers were used, respectively. Results indicated spatial and temporal distribution of either total coliform or E. coli in the subbasin. Total coliform and E. coli were consistently higher (p<0.05) in the northem tributaries than those in the south. Hydrologic characterization of soils in the sub-basin showed significantly higher Ksat and K(h) in the south of the sub-basin than the north (p<0.05). Preliminary results indicated that the presence of consistently higher number of total coliform and E. coli in the northern portion of the sub-basin was due in part to subsurface transport through the coarse texture soils in the south since the direction of flow is north. Further studies are underway to measure E. coli travel time and to characterize subsurface hydrology using non-invasive techniques.
Habitat Assessment of Selected Streams in the Mississippi River Alluvial Plain in Northwestern Mississippi and Eastern Arkansas: Winter and Summer 200
Year: Authors: Rebich R.A., Welch H.L., Coupe R.H.
The U.S. Geological Survey (USGS), in cooperation with MDEQ, collected water samples and assessed stream habitat at 43 MRAP sites in northwestem Mississippi (sites 8-50, fig. I) during two index periods (winter, January-April 2002, and summer, July-September 2002). Data were also collected at seven MRAP sites in eastem Arkansas (sites 1-7, fig. 1) during the same two index periods. The habitat assessment data are the focus of this report. This report: (1) documents methods of site selection and categorization, data collection, quality assurance/quality control, and statistical analysis; and (2) presents summaries of the habitat assessments and results of statistical analyses to determine if any of the habitat assessments could indicate a range of stream conditions for northwestern Mississippi streams.
Water Quality Analysis of an Intensively Used Agricultural Reservoir
Year: Authors: Moore M.T., Pierce J.R., Farris J.L.
The use of farm reservoirs for irrigation is gaining popularity in the Mississippi River Alluvial Plain (MRAP). Due to depletions of several aquifers, many counties within the MRAP have been labeled as critical-use groundwater areas. To alleviate the stress on these aquifers, many farmers are implementing storage reservoirs for economic reasons. Their benefits, however, extend into the surrounding environment. When used with a tailwater recovery system, reservoirs have the potential to accumulate nutrients, which decreases the need for fertilizer application with irrigation water. Also, potentially harmful contaminants (e.g. pesticides) are trapped and transformed within the reservoir, rather than being released through drainage into receiving systems such as lakes, rivers, and streams. Roberts Reservoir is an intensively used, 49 ha storage reservoir, located in Poinsett County, Arkansas. Water quality analyses and toxicity assessments of the reservoir and surrounding ditches indicated a stable water quality environment, with no observed toxic effects. The results of this study suggest that water released into a local receiving stream poses no contaminant risk and could be maintained for irrigation purposes, thereby reducing the need for groundwater depletion.
Planform Changes in the Pascagoula River and Tributaries, Mississippi
Year: Authors: Mossa J., Coley D., Ogbugwo M.
This paper examines planform changes in the Pascagoula River and tributaries in southeastem Mississippi, and its relationship to natural factors and human modifications in the basin. Planform changes were examined on the Pascagoula River and for portions of the Leaf River, Chickasawhay River. Bowie River, Thompson Creek and other tributaries that are wide enough to have two banklines visible on multiple series of maps and aerial photography. The planform changes are evaluated for a minimum of three periods including historic maps from 1947-51 (partial coverage), aerial photographs from 1955-1960, maps from 1982-86, and digital orthoquadrangles from 1992-96. In this large basin, floodplain land use/land cover is diverse, including national forests, commercial forestry, mining, urbanization, and agriculture. Spatial pattems and temporal relationships of floodplain changes and channel instability will be used to evaluate which locations are most unstable, whether modified portions are experiencing more instability than less modified portions, and evaluate cause and effect interactions. To better quantify change, we have developed and applied various methods to determine migration and changes in channel morphology using Geographic Information Systems.
A Survey of Lotic Tardigrades from the Pascagoula Drainage
Year: Authors: Niven A.
There are approximately 800 described species of tardigrades. These microscopic metazoans are commonly known as "water bears" because of their lumbering gait. The focus of this research is to identify and describe the association of tardigrades found in the Pascagoula drainage basin. Few studies of tardigrades from around the world are known from river systems and none from streams in Mississippi. Beyond this study, the community of tardigrades associated with this drainage is unknown. Samples were collected from stream substrate in several locations within the Pascagoula drainage basin from March to September 2002. Tardigrades were separated from the substrate, sorted and mounted for identification. Hypsibideae dominated the tardigrade community in all streams surveyed. While seasonality appears to influence the makeup of the communities, the greatest number of specimens was collected in the late spring and the most commonly observed genera was Hypsibius. Other commonly obselved specimens in included Isohybsibius and Ramazottius. Dactylobiotus was observed in many streams in low occurrence but independent of seasonality.
Port Sedimentation Solutions
Year: Authors: McAnally W.H., Haydel J.F.
The purpose of this paper is to present some engineering alternatives to dredging and illustrate their application by examples from the literature and a current example from Lowndes County Port on the Tennessee-Tombigbee Waterway. Engineering solutions to waterway sedimentation can be classified as those that keep sediment out, keep sediment moving, and remove deposited sediment, and numerous solutions are available within each category. Application of these principles to Lowndes County Port show that training structures constricting waterway width at the port can substantially reduce sedimentation within the port while providing both cost and environmental benefits. A sediment trap offers some of the port shoaling benefits, but at greater cost and without the environmental enhancement possibilities. These same principles can be applied to deep water ports and channels with similar benefits.
Improved Estimation of Nutrient and Pesticide Runoff Losses from Golf Courses and Residential Lawns in the South Atlantic-Gulf Region
Year: Authors: Massey J., Stewart B., Armbrust K., Johnson A., Smith C.
Turfgrass is the most intensively managed biological system in metropolitan areas. Currently, over 40 million acres of turf are estimated to be growing in the U.S. Following the national trend, turf acreage in Mississippi is expanding at a steady pace. Mississippi currently has an estimated 800,000 residential lawns comprising 300,000 acres and over 2,500 athletic fields. These figmes do not include turf maintained at city parks, schools, churches, cemeteries, aitports and industrial/commercial sites. An estimated 170 golf courses (ca. 15,000 A) are also in operation in MS. In addition, about 2 million A of highway roadsides are maintained in Mississippi, a significant portion of which are treated with one or more herbicides each year. In terms of residential lawns, homeowners tend to apply more chemical than is necessary for effective pest control. As a result, the use of pesticides by homeowners may be as high as 5 to 10 lbs. per acre, almost ten times more chemical per acre than is used by farmers. The intensity of pesticide and nutrient use, coupled with the anticipated continued growth in turf acreage, suggests that concems over the impacts of turf chemicals on surface water quality will likely increase over time. Unfortunately, current models used to estimate runoff from managed turf are not accurate, making it difficult to allocate between agricultural and urban sources of contamination and to assess overall turf impacts on water quality. This project is designed to improve the estimation of turf chemical runoff from warm-season turf managed according to conditions found on golf course fairways and residential lawns. Runofff plots planted in Bermudagrass and Zoysiagrass are being established at MSU’s Blackbelt Experiment Station and will be used to study the effects of grass species and management regime on turf chemical runoff using simulated rainfall. Laboratory studies are being conducted to assess the role of thatch on pesticide runoff. This research is part of a larger study that includes Malyland, Oklahoma, and Minnesota that is designed to determine regional differences in turf chemical runoff. Each study site will use the same EPA-approved field protocol that involves the application of 2,4-D herbicide, flutolanil fumgicide, and chlorpyrifos insecticide.
Presence of Altrazine in Water in a Recharge Area of Guarany Aquifer in Brazil
Year: Authors: Cerdeira A.L., Santos N.A., Pessoa M.C., Smith, Jr. S., Lanchote V.L.
The region of Ribeirao Preto City located in Sao Paulo State, southeastem Brazil, is an important sugarcane, soybean and corn producing area. This region is also an important recharge area for groundwater of the Guarany aquifer, a water supply source of the city and region. The cultivation of grain and sugar cane in this area demands the frequent use of the herbicide atrazine (2chloro- 4- (ethylamino)-6-(isopropylamino)-S-triazine). This research was conducted to characterize the potential contamination of groundwater with atrazine. Surface water samples were collected in the Espraiado stream in a selected watershed on the area, during the years of 1995-1998. Groundwater was also collected in wells located at the edge of the watershed during the years of 1999 to 2002. The water samples were analyzed by HPLC (High Perfonuance Liquid Chromatography) procedure followed by GC-MS for confinuation. To predict the atrazine leaching in the area, the CMLS-94 (Chemical Movement Layered Soil) simulation model was also used. Only four atrazine detections in surface water were found. however, none of them were confirmed with GC-MS. No atrazine was detected in groundwater samples. The results obtained by the CMLS-94 simulations predicted that atrazine, after four years from the application date, would not have reached the depth of the confined aquifer (40m).
Constructed Wetlands: An Eduge-of-field Management Practice for Reduction of Coliforms
Year: Authors: Cooper C.M., Knight S.S., Testa, III S.
A three year study evaluated a constructed wetland system located southeast of Hernando, Mississippi, built for treatment of dairy farm wastes that flowed indirectly into the Coldwater River upstream of Arkabutla Reservoir. These dairy wastes contained excessive concentrations of fecal coliform bacteria that potentially could harm humans using the river and reservoir for recreation and fishing. In Mississippi, as nationally, coliforms are a predominant reason for waterbody impairment, and Mississippi’s 2002 Clean Water Act section 303(d) list included 15 impaired segments within the Coldwater River watershed due to pathogen contamination. Our study exemplifies the great potential for small size constructed wetlands to mitigate coliform bacteria pollution from cattle production areas.
The Demonstration Erosion Control Project: Aspects of Water Quality in Abiaca Creek, Mississippi
Year: Authors: Cooper C.M., Lizotte, Jr. R.E., Knight S.S., Moore M.T.
The purpose of this study was to examine selected water quality parameters both spatially and temporally in Abiaca Creek using univariate and multivariate analyses to elucidate trends. The watershed was monitored monthly at eight sites from 19922002 for 14 water quality parameters. Results of spatial univariate analysis showed significant differences among sites for 13 of 14 water quality variables, whereas temporal analysis revealed differences among years for 12 of 14 variables. Exploratory multivariate analysis revealed spatial trends in water quality with upstream sites having overall better water quality than downstream ones. Observed spatial trends in water quality are influenced by localized geographic characteristics (e.g. localized land use practices, gravel mining, flood control structures, etc.). Temporal results showed a greater complexity in annual water quality with trends less evident and most likely associated with fluctuations in annual climatic conditions. Changes in water quality were cumulative due to major watershed inputs with instream reservoirs resetting dissolved oxygen and ammonia levels.
Pesticide Concentrations in Surface Waters of Mississippi Lakes and Reservoirs
Year: Authors: Cooper C.M., Smith, Jr. S., Folmar H.
Of the pesticides that have United States Environmental Protection Agency (U.S. EPA) or state of MiSSIssippi water quality criteria, only ten collections were excessive. Survey collectIons are not intended as substitutes for the robust sampling protocol needed for regUlatory purposes, but they serve as an adequate screening tool for specific sites or pesticides. Understanding trends in pestIcide presence could result in more effective methods to prevent environmental contamination.
Effects of Mississippi Delta Sediment Contaminants on CYP1B-Gene Expression in Channel Catfish
Year: Authors: Willett K., Butala H., Patel M., Quiniou S., Waldbieser G.
Sediments in some Mississippi rivers and lakes contain significant concentrations of environmental contaminants including pesticides and industrial by-products. Chemical analysis of sediments collected from three Mississippi Delta waterways (Lake Roebuck, Bee Lake and Sunflower River), suggested that polycyclic aromatic hydrocarbon (PAH) and organochloline pesticides were highest at Lake Roebuck. Our research has been investigating the potential for sediment associated contaminants to cause physiological effects in channel catfish, specifically on CYP1B gene expression. CYP1B is a P450 gene that in mammals is involved in the metabolism of PAHs and estradiol to potentially toxic intermediates. Quantitating induction of CYP1B mRNA or estrogen metabolism in catfish could potentially be a useful biomarker of exposure. The objectives of our study were to characterize in vivo CYF1B mRNA expression and estrogen metabolism in laboratory raised and wild-caught channel catfish (lctalurus punctatus) from Lake Roebuck, Bee Lake and Sunflower River. Initial experiments involved cloning the channel catfish CYP1B gene. Preliminary cloning results suggest that the channel catfish sequence contains 510 amino acids and has a 55 and 50% identity with the human and scup CYP1B genes, respectively. Laboratory fish were exposed i.p. to corn oil or 20 mglkg benzo(a)pyrene (BaP) for 4 days. Using quantitative real time RT-PCR, BaP exposure induced CYP1B mRNA in blood, liver and gonad tissues. CYP1B mRNA levels from Delta catfish were not statistically increased relative to control fish, and CYPIB levels from the livers of these animals were significantly lower than laboratory controls. The relative tissue levels of CYP1B mRNA from Lake Roebuck fish were gill > blood > liver =gonad. Liver microsomes metabolized estradiol to predominately 2-hydroxyestradiol and estrone, however a statistically higher 4:2-hydroxyestradiol ratio was found in BaP exposed animals (0.17) compared to controls (0.04), suggesting that BaP caused induced formation of the genotoxic 4-hydroxyestradiol metabolite. Liver microsomes from the Delta fish produced statistically more 4-hydroxyestradiol compared to control animals but less than the BaP exposed fish. These results will ultimately help characterize the utility of CYP1B as a marker of environmental contamination and the physiological significance of CYPIB in fish.
How are Native Wetland Plants Useful in Mitigating Nutrient Runoff from Agricultural Fields:
Year: Authors: Beadle J., Kroger R., Holland M.M., Moore M.T., Cooper C.M.
Human activities have altered the global biogeochemical cycle by doubling the rate of nitrogen input into terrestrial ecosystems (Smith et al., 1999). Likewise, land use has a similar effect on phosphorus. The loading of nitrogen and phosphorus into the world’s rivers, lakes. aud oceans is strougly influenced by human population densities, population densities of livestock, and land use (Pringle. 2003). Nutrients are the 3rd largest agricultural pollutant in Mississippi, following sediment and pathogens (Moore and Cooper, 2003). Wetlands serve as natural buffers for rivers, lakes, and streams (Holland, 1996). By maintaining these wetlands around agricultural landscapes, significant improvements in water quality may be achieved. (Moore and Cooper. 2003),
Optical fiber chemical sensor for water quality monitoring
Year: Authors: Tao S., Fanguy J.C., Gong S.F., Soni K.
An optical fiber chemical sensor (OFCS) can detect and measure the concentration of a compound by sensing the interaction of the compound with the light propagating in an optical fiber.1 Depending on the location at which the interaction occurs, optical fiber chemical sensors can be divided into two classes: active core fiber optic sensor (ACFOS) and evanescent wave fiber optic sensor (EWFOS). In an ACFOS, the interaction of an analyte compound with light occurs inside an optical fiber core, while in an EWFOS, the interaction of an analyte compound with light occurs in the cladding layer of an optical fiber. A light beam traveling down an optical fiber can be scattered or absorbed by a compound existing inside the fiber core or the cladding as an impurity or as a dopant. The light propagating in an optical fiber can also excite a compound in the fiber to a higher energy level and causes the emission of fluorescence. All these interactions can be used in designing an OFCS. Therefore, analytical spectroscopic techniques, such as ultra violet/visible (UVNis) absorption spectrometry, infrared (IR) absorption spectrometIy, Raman scattering spectrometry, fluorescence (FL) spectrometry, etc., have been used in OFCS design. 2 The characteristics, including sensitivity, response time, selectivity, etc. of an OFCS are decided by the properties of the compound to be detected, the analyte/light interaction used for the detection, the location of analyte/light interaction, and the micro structure of the optical fiber and the cladding.
Water Saving Irrigation: A Vital Step in Improving the Sustainability of Rice (Oryza sativa) Production in the Mississippi Delta
Year: Authors: Smith M.C., Massey J., Thomas J., Locke M., Norris J., Pennington D., Johnson A.
This project aims to reduce water use and non-point source pollution in rice production by coupling multiple-inlet irrigation with intermittent flooding. Multiple-inlet irrigation uses gated polypropylene pipe to distribute water to each paddy individually. With intermittent flooding, the paddy water is allowed to naturally decline through evapotranspiration until approximately 1/2, of the soil surface of each paddy is exposed. Extension and research personnel have intl’oduced the combined irrigation practices to Arkansas and Mississippi producers and are adapting the practices to the grower’s requirements so as to better understand soil and climatic effects on season-long water use, pumping costs, pest levels, and rough rice yields.
Understanding the Link between an Aquatic Shoreline and an Urban Development: A Mission of Planning and Management
Year: Authors: Sobley J., Verseman R., Bailey M., Murdock J.
In July of 2003, a preliminary master plan was presented to state and local leaders of Smith, Rankin, Jasper, Jones County for the development of a recreational facility including a lake. The 900 acre lake and surrounding infrastructure will be a mixture of business, residential, and traditional park atmospheres within the Bienville National Forest, and will be planned with the ideas of sustainable management and planning practices to ensure a high water quality within the lake and the surrounding creeks and tributaries. This project will be devoted to the development of a marina and commercial area and will mimic the ideas of New Urbanism while paying attention to the issues of water management and planning along the aquatic shoreline. A fully designed master and water management plan will be developed for the lake.
Geospatial Applications for Water Management Agencies in the Upper Pearl River Basin
Year: Authors: Tagert M.L., Ballweber J.A., Shaw D.R.
Mississippi State University’s GeoResources Institute (GRI) has been cooperating with state and regional agencies to apply geospatial technologies to address diverse water quality and public health concerns in Mississippi. The GRI is working primarily with the Pearl River Valley Water Supply District (PRVWSO), but also with other state agencies including county governments, rural water associations, private landowners, and others on a growing effort in the Upper Pearl River Basin to demonstrate the potential of geospatial technologies for improving the efficiency and effectiveness of land and water resources management. Much of the information necessary for watershed planning and management has a spatial context and is ideal for inclusion in a geographical information system (GIS). Also, much of the same data are important for decision-making regarding both water quality and public health protection. Many national GIS data sets are available from the Environmental Protection Agency and other agencies. Although these large-scale data sets are often helpful, the GRI has focused on data layers that are very site-specific. Examples of such data layers are water and wastewater infrastructure features, locations of National Pollution Discharge Elimination System (NPDES) permits, impaired waters on the 303(d) list, and high-resolution, orthorectified imagery, to name a few. This project is alloWing the GRI to work cooperatively with the PRVWSO and other Upper Pearl River Basin stakeholders to obtain and organize remotely sensed imagery and other relevant data into themes that can be layered in a GIS. Furthermore, as data layers are obtained and developed, they can be shared with other local stakeholders, such as county GIS personnel. The GRI has learned that, as other agencies voluntarily share geospatial data, it is an ideal opportunity to build or expand locally led watershed advisory groups. In the Upper Pearl River Basin, geospatial technologies are already leading to increased efficiency, better planning, and more accurate decisions regarding water quality, water quantity, and public health concerns.
Sampling strategy and selected water-quality and bottom-material data for the Deer Creek, Mississippi, Synoptic Study
Year: Authors: Rebich R.A.
The Deer Creek Basin, in northwestern Mississippi, is located in the Mississippi River Alluvial Plain, an area locally referred to as the Mississippi Delta. Deer Creek begins at Lake Bolivar at Scott, north of Greenville, and empties into the Yazoo River north of Vicksburg (fig. 1). The channel meanders from north to south and is 164 miles long. The drainage area at the mouth is about 110 square miles. The basin drains a largely rural, agricultural landscape, but includes small communities such as Scott, Leland, Hollandale, Rolling Fork, Cary, and Valley Park. Flow in the upper part of the basin is semiregulated by several small weirs. Much of the Deer Creek channel below Greenville is "perched" or elevated formed by natural levees such that overland runoff drains away from the main channel, and only local runoff drains into the main channel. Flow is diverted into Rolling Fork Creek at Rolling Fork, which is located near the center of the basin. The Deer Creek channel below Rolling Fork is actually a series of small "lakes" or cutoffs created by earthen crossings underlain with culverts. Many of the culverts are partially filled with sediment or have inadequate cross-sectional area to convey flow from Rolling Fork to the mouth of the creek at the Yazoo River. Illegal trash dumping, failing septic systems, and agricultural runoff are well documented in the basin, especially in the lower part. The U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the Mississippi Department of Environmental Quality (MDEQ), the Yazoo-Mississippi Delta Joint Water Management District, and the U.S. Geological Survey (USGS) have initiated a restoration effort for the Deer Creek Basin. Before restoration efforts began in the basin, the USGS conducted a synoptic study in September 2002 to collect baseline water-quality, bottommaterial, habitat-assessment, and macroinvertebrate data in Deer Creek. This report describes the sampling strategy for the Deer Creek synoptic study, including site selection, sampling methods, quality-assurance and quality-control methods, and listing of analytes and laboratories. This report also includes selected water-quality and bottommaterial data collected during the Deer Creek synoptic study.
Evaluationa of headwater streams on the Camp Shelby training site in South Mississippi based on the EPT complex (Ephemeroptera, Plecoptera, and Tric
Year: Authors: Wilberding A.L., Howell F.G.
Mayflies, stoneflies, and caddisflies are pollution sensitive aquatic insects in their immature stages and make up the Ephemeroptera-Plecoptera-Trichoptera (EPT) Index, often used to characterize the "environmental health" of streams. The number of distinct taxa within these orders determines the EPT Index of a sample collection; the numerical value of this index increases as water quality increases. Another water quality index is the Biotic Index that uses species tolerance values to determine a stream’s overall water quality. Tolerance values range from 0 to 10, with 0 indicating no tolerance to pollution. The Biotic Index uses the same ranges, therefore, the lower the Biotic Index of a stream, the "healthier" the stream. We have been using EPA’s Multi-Habitat Approach to evaluate the macroinvertebrate communities associated with seven headwater streams at Camp Shelby Training Site in south Mississippi since 1997. Results for 16 collections show that the EPT species complex is reasonably consistent in composition across streams and seasons. Seasonal averages for the EPT Index range from four to seven, while site averages range from two to eight. In all, there were 24 species of Ephemeroptera, 14 species of Plecoptera, and 23 species of Trichoptera. Seasonal Biotic Indices range from 5.5 to 6.6. Site Biotic Indices range from 5.4 to 6.4.
Macroinvertebrates associated with headwater streams at Camp McCain training site, Mississippi
Year: Authors: Ducote E.T., Howell F.G.
Keeping with good environmental stewardship in 1997 the Mississippi Military Department implemented an Aquatic Biomonitoring Program at the Camp McCain Training Site in Grenada County, MS. The objective of this program is to determine the status of the water resources (Are the designated/beneficial and aquatic life uses being met?). Rapid bioassessment using the benthic macroinvertebrate assemblage has been the most popular set of protocols among water resource agencies since EPA published their first edition of Rapid Bioassessment Protocols for use in Wadeable Streams and Rivers in 1989, and the second in 1999. Systematic sampling of three headwater streams (Crowder, Epison and Campbell) has been conducted each autumn, beginning in 1997-current, at designated 100 m reaches exiting the camp. Biannual sampling began in 2002 with the inclusion of a spring sampling period. Sampling twice a year will accommodate seasonal variation of the macroinvertebrate community. A multihabitat procedure using a D-frame dip net is the sampling method used. EPA indicates that this technique is scientifically valid for low-gradient streams. Taxonomy is to genus/species, which provides more accurate information on ecological/environmental relationships and sensitivity to impairment. Benthic metrics used to evaluate aspects of both elements and processes within the macroinvertebrate assemblage are; Taxa Richness, EPT index, EPT/Chironomidae, Functional Feeding Groups, NC Biotic Index and, Shannon "diversity and evenness" indexes. Water quality assessments and autumnal community trends of each headwater stream are based on current site-specific monitoring data.
Community composition of sand-dwelling chironomids in three blackwater streams
Year: Authors: Fitch R.C., Beckett D.C.
The majority of streams in Mississippi have sand bottoms. In this study we investigated the larval chironomid (Diptera: Chironomidae) composition in the spring and summer in three sandy-bottomed blackwater streams located in southern Mississippi. The principal objective of this study was to describe how the chironomid communities in sand substrates varied among sites within a stream, as well as among streams. We were also interested in seasonal changes in chironomid communities. Most of the animal biomass collected from sandy substrates is in the form of relatively small invertebrates, including the chironomids. In all sites the most common chironomid larvae was Rheosmittia sp., which accounted for 50-90% of the chironomids collected. Rheosmittia sp. is a very small chironomid and is an obligate sand dweller in streams and rivers. The mean density of Rheosmittia sp. from the spring data in Black Creek is approximately 133,000 individuals/m2 in sandy substrate. Based on evidence from our laboratory, this genus of chironomid dominates sand substrates from streams of the size investigated in this study up to and including the lower Mississippi River. Other chironomid taxa found in the present study included Polypedilum scalaenum group, P. halterale group, Paracladopelma sp., and Stictochironomus sp. In addition to characterizing the invertebrate fauna of sand substrates, we plan to determine if these communities will serve as indicators of pollutional disturbance.
Surface Water Sampling and Analysis for Comparisons with the USDA’s AGNPS Model Predictions for the Upper Pearl River Watershed.
Year: Authors: Tagert M.L., Massey J.H., Shaw D.R., Kroll M.B., Smith M.C., O'Hara C.G., Bingner R.L.
As a result of recent legislation, the nonpoint source component of the 1972 Clean Water Act is now being implemented by the Environmental Protection Agency (EPA). Each state must submit a list of impaired waters to the EPA, and a Total Maximum Daily Load (TMDL) must eventually be established for each waterbody listed as impaired. Mississippi currently has 732 waters listed as impaired, with 25 of those impairments occurring in the Upper Pearl River Watershed. Contamination by pesticides is often listed as the reason for impairment in these and other Mississippi surface waters. In addition, the Upper Pearl River ultimately feeds into the Ross Barnett Reservoir, which is the drinking water supply for Jackson, MS. However, due to changes in land use/land cover in the Upper Pearl River Watershed, waters that were once impaired by pesticides may not currently be impaired. To assess the current level of impairment by pesticides in this watershed, a sampling regime was implemented to collect grab samples at seven gauged locations within the watershed. Samples were collected weekly from May through August 2002, and monthly thereafter. Samples were extracted via Solid Phase Extraction (SPE). Each extracted sample set includes two-liter samples from the seven selected sites, two lab spikes in deionized (DI) water, a field spike, a DI water blank, and a glassware wash. A multi-residue method was then used to analyze the surface water samples for fifteen pesticides: triclopyr, 2,4-D, tebuthiuron, simazine, atrazine, metribuzin, alachlor, metolachlor, cyanazine, norflurazon, hexazinone, pendimethalin, DDT insecticide degradation product, - p, p’-DDE -, diuron, and fluometuron. Mean percent recoveries for spiked samples ranged from 39% for metribuzin to 120% for norflurazon. However, most average spike recoveries fell within an acceptable range (i.e., 85 to 95% recovery). Tebuthiuron, 2,4-D, metolachlor, and hexazinone were detected in ten or more samples out of a possible 36 samples. Fluometuron was the only compound that was not detected at any of the seven sites, while pendimethalin and metribuzin were only detected at one site to date. See Table 1 for ranges of concentrations detected in samples and the corresponding Health Advisory Levels (HAL) for each compound, if applicable.
Field sampling of soil and surface water at and near small arms training areas
Year: Authors: Bestor M., Bricka M.
The purpose of this presentation is to discuss the impacts of lead as a result of small arms training to the environment. The malleability, resistance to corrosion, and abundance of lead made it an obvious choice for ammunition. However, studies conducted over the past two decades have shown that there may exist a threat to humans and wildlife due to the toxicity associated with lead. More recently, interest has increased regarding the effects of solubility and transport of lead particles from soil into surrounding watersheds. The focus of this investigation was to observe lead concentrations in the soils and watersheds surrounding areas of suspected contamination. Soil samples were collected from areas suspected of containing elevated levels of lead. Water and sediment samples were collected from streams where surface runoff and drainage from the areas of concern was observed. This investigation also sought to collect data focusing on the change in dynamics effecting lead movement brought on by rain events. Storm water samples were collected using an automatic sampling device. The results indicate only trace amounts of lead movement from areas of elevated lead concentrations during normal conditions, but higher levels were detected during periods of high rainfall.
The Mississippi geospatial sub-watershed boundary
Year: Authors: Clair, II M.G., Turnipseed D.P.
Since the passage of the Clean Water Act in 1972, the need for digital hydrologic data by Federal, State, and local agencies as well as scientists and consultants in the private sector to make decisions, do analyses, and to model water-quantity and quality issues on a watershed basis has grown rapidly. Both raster- and vectorbased geospatial data are needed to accomplish such tasks as establishing and implementing Total Maximum Daily Loads (TMDLs) and source-water protection. Digital drainage-area data, at the watershed scale, are not available in many States. In 1999, the U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS); the U.S. Department of Agriculture, Forest Service; the Mississippi Department of Environmental Quality, Office of Pollution Control (MSDEQ-OPC); and the Mississippi Automated Resources Information Service (MARIS); began development of geospatial techniques to create a digital watershed boundary dataset (MS-WBD) for the State of Mississippi. The MS-WBD was derived from published 1:24,000-scale 7.5-minute topographic quadrangle sheets on which sub-watershed boundaries had been delineated. Watershed and sub-watershed boundaries were digitized and entered into a geospatial database. Environmental System Research Institute’s (ESRI) Arc/Info software and its ArcEdit module (the use of firm, trade and (or) brand names in this report is for identification purposes only, and does not constitute endorsement by the U.S. Geological Survey). were used to capture and process the digitized data. Als+o using Arc/Info software, the MS-WBD was attributed with information such as: <ul><li>Watershed sub-watershed names</li> <li>Hydrologic unit code</li> <li>Drainage areas</li></ul> This finalized MS-WBD will present information on drainage and hydrography in the form of hydrologic boundaries of water-resource regions, sub-regions, accounting units, cataloging units, watersheds, and subwatersheds. The final MS-WBD will be added, along with appropriate metadata, to the USGS National Elevation Dataset (NED) and National Hydrography Dataset (NHD) to help scientists and engineers address issues in watershed management, water-+quantity and quality initiatives, and watershed modeling. Arc Macro Language (AML) is also being used to develop applications to determine geomorphological characteristics such as slope and mean channel length for use in flood frequency and low-flow duration computations for the State. This map and associated watershed and sub-watershed boundaries will provide a standardized base for use by water-resource managers, engineers and planners in locating, storing, retrieving and exchanging hydrologic data.
Assessing functional integrity of moist-soil management wetlands by comparison with nearby non-managed systems
Year: Authors: Ervin G.N., Bried J., Herman B.
Our objective was to evaluate impacts of moistsoil habitat management on water quality and biological communities in wetland areas at the Strawberry Plains Audubon center in Holly Springs, MS. The study area is a 1000-ha farm presently undergoing conversion from agricultural land to wildlife habitat under the supervision of Audubon personnel, who assumed management of the property in 1998. In assessing the ecological status of the study wetlands, we evaluated a suite of physical water quality parameters (dissolved oxygen, turbidity, conductivity, pH, alkalinity, and temperature); concentration of nutrients, sediment, and chlorophyll a within surface waters; and plant cover, biomass, and species richness. Certain attributes of these systems (dissolved oxygen, turbidity, and conductivity) did indicate differences among the wetlands under investigation. Among these, turbidity seemed most closely correlated with initial management activities. However, perturbations, as indicated by increased turbidity during installation of water control structures, were short-lived, presumably because of post-agriculture recovery already underway in the watersheds surrounding the study sites. Based on data collected during the year prior to active wetlands management by Audubon, six impoundments were selected for continued monitoring following installation of standpipe control structures and initial management activities. These sites include four farm ponds (two unmanaged and two that will be managed to enhance moist-soil habitat), one natural beaver impoundment, and one created riparian wetland (Study Sites, at right). Recovery of the managed wetlands will be assessed in comparison with non-managed sites at Strawberry Plains, including the on-site beaver impoundment.
Phosphorus inactivation and odor control in animal waste lagoons, growing facilities, and natural surface water
Year: Authors: Lind C.B.
Nutrient Inactivation, specifically Phosphorus Inactivation is the interception and chemical precipitation of phosphorus from the soluble reactive form into an insoluble un-bioavailable form. The algae responsible for eutrophication of surface waters need their nutrients soluble-they have no roots to chemically solubilize and absorb nutrients. Precipitation of phosphorus with aluminum and iron compounds has been an integral part of lake restoration since 1968. Over 200 lakes have been treated to eliminate P as a nutrient. Using the same chemistry animal wastes can be treated to precipitate P prior to final disposal, or better reuse. Ferric iron sulfate has the added benefit of precipitating the odiferous, toxic, and corrosive hydrogen sulfide (H2S) from sludges and liquid streams. Hydrogen sulfide can also be effectively controlled by sodium nitrite. The use of alum or iron in waste streams will also control struvite. These chemicals, their applications and case studies will be presented in an overview format.
Reduced water use and methane emissions from rice grown using intermittent Irrigation
Year: Authors: Massey J.H., Scherder E.F., Talbert R.E., Zablotowicz R.M., Locke M.A., Weaver M.A., Smith M.C., Steinriede R.W.
Current rice production techniques in the U.S. are water intensive and have led to groundwater depletion in some areas of the Mississippi Embayment aquifer system. Flooded rice culture also contributes to global climate change through the production of methane, a greenhouse gas. Our preliminary research indicates that intermittent rice irrigation techniques, where the height of floodwater cycles between 0 to 15 cm rather than being maintained at a constant height of about 15 cm, can reduce season-long water inputs by up to 50% over conventional (continuous flood) methods with only small reductions in yield. The production of methane gas was reduced by about 70% using intermittent irrigation compared to continuously flooded rice paddies. Future research needs to assess the utility of intermittent irrigation to maintain rice productivity while reducing water use and methane emissions across the various soil and climatic conditions in the Mississippi Embayment region.
CYP1B MRNA expression and estrogen metabolism in channel catfish collected from Mississippi Delta
Year: Authors: Patel M.
CYP1B1 is a P450 gene that in mammals is involved in the metabolism of polycyclic aromatic hydrocarbons (PAHs) and estradiol to potentially toxic intermediates. Certain environmental contaminants found in Mississippi sediments act by binding to the aryl hydrocarbon receptor (AhR) and inducing a gene battery that includes CYP1B and CYP1A. In mammals, CYP1B1 metabolizes estrogen to 4-hydroxyestradiol whereas CYP1A metabolizes it to 2-hydroxyestradiol. Quantitating induction of CYP1B mRNA or estrogen metabolism in catfish could potentially be a useful biomarker of exposure to AhR ligands. The objective of our study is to characterize in vivo and in vitro CYP1B mRNA expression and estrogen metabolism in laboratory raised and wild-caught channel catfish (Ictalurus punctatus, CC) from Lake Roebuck, Bee Lake and Sunflower River. Laboratory fish were exposed to corn oil or 20 mg/kg benzo(a)pyrene (BaP) for 4 days. Using quantitative real time RT-PCR, BaP exposure induced CYP1B mRNA in blood, liver and gonad, CYP1B mRNA in wild catfish was not statistically increased relative to control fish. The relative tissue levels of CYP1B mRNA from Lake Roebuck fish were gill >> blood > liver = gonad. CYP1B mRNA showed more induction in primary cultured gill cells compared to hepatocytes following BaP exposure (5x10-9 to 5x10-5 M). Ongoing work is investigating if other AhR ligands also induce CYP1B mRNA in vitro. Liver microsomal ethoxyresorufin-O-deethylase (EROD) activities from wild fish were intermediate between control and BaP-exposed animals. Liver microsomes metabolized estradiol to predominately 2-hydroxyestradiol (compared to 4 hydroxyestradiol) and metabolism was induced by BaP. In gill microsomes, EROD activities and estrogen metabolism were much lower compared to liver. Also gill microsomes did not form any 4-hydroxyestradiol. These results will ultimately help characterize the utility of CYP1B as a marker of environmental contamination.
Monitoring the quality of water in the unsaturated zone at Camp Shelby and Camp McCain, Mississippi
Year: Authors: Murphy L.O., Cooksey C., Lemire R., Slack L.J.
During 2002 the U.S. Geological Survey, in partnership with the Mississippi Army National Guard, began a study to determine the quality of water in the unsaturated zone (soil zone above the water table) at Camp Shelby and Camp McCain, Mississippi. Eight soil-water samplers (lysimeters) were installed at shallow depths at selected locations at Camp Shelby (near Hattiesburg) and six were installed at shallow depths at Camp McCain (near Grenada). Two lysimeters installed for another study near Greenwood were used for quality control/quality assurance purposes (to determine reference/background conditions). The lysimeters were periodically purged to remove all water introduced during the installation. Specific conductance and/or other water-quality measurements were made to determine when the water being collected was representative of that in the unsaturated zone (and uninfluenced by the installation of the lysimeters). When conditions were satisfactory, soil-water samples were obtained from these lysimeters and analyzed for major anions, major cations, dissolved metals, nutrients, volatile organic compounds, semi-volatile organic compounds, and explosives.
Adaptive hydrologica and meterologic instrumentation for flood warning in the Limpopo River Basin of Botswana
Year: Authors: Stocks S.J., Turnipseed D.P.
Near real-time, low maintenance hydrological and meteorological instrumentation is needed in remote access areas subject to periodic flooding. In Botswana, there is limited coverage of hydrological and meteorological monitoring stations in the Limpopo River Basin, and only a few stations provide near real-time reporting capability. During 1999-2000, many parts of the Southern African Region experienced devastating floods, most of which occurred from December 1999 through March 2000. Rainfall accumulations during February 2000 in Botswana have been estimated in some areas to have been greater than 1,000 millimeters (39.4 inches) in one storm event, which is more than twice the annual average rainfall. Many lives were lost; tens of thousands of people were displaced from homes; and more than $285 million of damage was reported. The local waterrelated agencies were not adequately equipped to respond to these rapidly occurring major flood events. In addition, the local data-collection agencies currently operate antiquated river-gaging equipment that has no dynamic capacity to convert the raw data into the type of information needed by the Republic of Botswana National Disaster Management Office (NDMO). The information available to the decision makers during this flooding could have been significantly improved by the installation of additional, strategically placed, near realtime river and rainfall monitoring stations. In coordination with a project entitled "Village Flood Watch: A program for the Improved Preparedness, Warning and Response in the Limpopo River Basin in Botswana," personnel of the U.S. Geological Survey (USGS) designed and constructed eight hydrological and meteorological monitoring stations for the special environment in the Limpopo River Basin of Botswana. The project was made possible by a grant from the U.S. Agency for International Development / Regional Center for Southern Africa (USAID/RCSA) located in Gaborone, Botswana. Three of the eight gages constructed record continuous river stage using a new non-contact sensor recently tested and approved for use by the USGS in river monitoring. This non-contact sensor, which measures river stage using micro-pulse radar technology, is currently being beta-tested at two streamgages in Mississippi. The unique adaptation of this technology for USGS application in Botswana provided the project with the ability to quickly and efficiently construct near real-time hydrological monitoring stations on three bridges. Other construction on the project included retrofitting three existing stilling wells used as river monitoring stations in the Limpopo River Basin and construction of two meteorological gages to record continuous rainfall, wind speed/direction, barometric pressure, relative humidity, and air temperature. The meteorological stations were designed for construction at selected secondary schools within the Limpopo River Basin for the dual purpose of providing additional meteorological data and adding to the school curriculum in the study of Earth sciences. All the hydrological and meteorological stations transmit data via the Meteorological Satellite (METEOSAT) operated and maintained by the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) in Darmstadt, Germany. This effort provides hydrological and meteorological parameters and a pilot hydrological run-off model that will assist the Botswanan government agencies in the propagation of hydrological run-off models in all the subbasins of the Limpopo River Basin for use in the future flooding disasters.
Spatial technologies assessing rural septic systems (STARSS)
Year: Authors: O'Hara C.
Over one third of Mississippi residents depend on septic systems to dispose of household waste water. Septic system failure is particularly a problem in fast growing rural areas. The Spatial Technologies Assessing Rural Septic Systems (STARSS) project plans to locate and map these problems using mobile computing, field mapping, remote sensing, and GIS technologies. In many cases, the locations of rural septic systems are poorly mapped and only known to workers. The STARSS pilot project effort is directed at developing a GIS/GPS field application for septic system mapping, inspection, and fault reporting. The intended product is a simple, user friendly, portable application to standardize the locating and mapping of the septic system while providing attribute information of the location. The custom application being developed will leverage PDA, GIS, and GPS technologies. The application will integrate selected basemap information downloaded from a server in a seamless application for the user and will have custom menus and interfaces that meets the field mapping needs of the application. The STARSS project is funded by the MSU GeoResources Institute (GRI) and Mississippi’s Water Resources Research Institute’s (WRRI) Southeastern Regional Small Drinking Water Systems Technical Assistance Center through a U.S. Environmental Protection Agency grant.
Hydrogeologic Significance of Pesticide and Nitrate Concentrations in the Water- Table Aquifer and Memphis Aquifer in the Memphis Area, Tennessee
Year: Authors: Bryson J.R., Welch H.L., Coupe R.H.
The Memphis, Tennessee, area uses ground water pumped from the Memphis aquifer as a major source of drinking water. The Memphis aquifer was assumed to be protected from surface contamination by the overlying deposits of low hydraulic conductivity which separate the Memphis aquifer from the alluvial and fluvial deposits that make up the shallow water-table aquifers. Graham and Parks (1986), Parks (1990), and Kingsbury and Parks (1993) determined that the confining unit between the Memphis aquifer and water-table aquifers is heterogeneous and discontinuous in many areas, allowing for direct recharge to the Memphis aquifer from the water-table aquifer. Therefore, water in the Memphis aquifer in the Memphis area could be vulnerable to contamination by surface-applied chemicals, such as pesticides and fertilizers.
Water monitoring program in a recharge area of the Guarany Aquifer in South America
Year: Authors: Cerdeira A.L., Neto C.F., Pinto O.B., Rampazzo P.E.
The Guarany aquifer is the greatest groundwater reservoir of water in South America and its extension covers the central-south part of Brazil, northern Argentina and part of Uruguay and Paraguay. The region of Ribeirao Preto, Sao Paulo State, Brazil, is located on a recharge area of Guarany aquifer and has sugar cane as its main agricultural activity. Based on the use of a number of pesticides and fertilizers in the sugar cane crop management and the natural vulnerability of recharge area, the Brazilian Agricultural Research Agency (EMBRAPA-Environment) carried out a number of studies in this region to study the quality of the Guarany aquifer water from 1995 to 1999. Results of these studies are published in a number of papers and showed no evidence of contamination of Guarany aquifer water. Tebuthiuron, (N-[5-(1,1-dimethylethyl)-1,3,4- thiadiazol-2-yl]-N,N’-dimethylurea), is a phenylurea herbicide used in sugar cane for preemergence control of weeds and was one of the pesticides monitored in the area. During the years of 2000 and 2002, EMBRAPA-Environment and Dow AgroSciences established a partnership in order to continue monitoring tebuthiuron in wells used in this region to supply drinking water to the population of Ribeirao Preto city region. Nine different sampling points were selected in the region and their wells were sampled from November 2000 to November 2002, covering samplings in rainy and dry seasons during this period. An analytical method using HPLC and UV detection was established to perform residue analysis. The limit of quantification used was 0.1 µg/Kg (ppb, part per billion) for the first three sampling carried out and 0.03 µg/Kg for the following five samplings. The majority of samples showed no detectable residues of tebuthiuron and two samples showed residues below the 0.03 µg/Kg limit of quantification, well below EPA’s Lifetime Healthy Advisory limit of 500 µg/L for tebuthiuron in drinking water. The results confirm no changes in the quality of water in this recharge area of Ribeirao Preto region for the specific compound monitored in the present study.
Fish tissue contaminant concentrations in regions of the Yalobusha River and Grenada Reservoir watershed
Year: Authors: Cooper C.M., Testa, III S., Knight S.S., Welch T.D.
The Yalobusha River and its recipient, Grenada Reservoir, are frequently used by recreational and subsistence fishermen. The watershed is currently receiving major modifications designed to remedy widespread channel instability and flooding in the Calhoun City, MS, region caused by a large debris jam that has occluded the river channel. These remedial actions should decrease future fisheries contamination by decreasing contaminant inputs. To provide a base line of current contaminant concentrations in the system, we analyzed available data on metals, persistent pesticides, and PCB concentrations from 462 fish. Highest average arsenic (11.8 ppm), copper (2.26 ppm), and lead (0.318 ppm) tissue concentrations (viscera, flesh, and whole fish) were observed in the river downstream of the debris jam, while highest average concentrations of iron (137 ppm), chromium (0.308 ppm), cadmium (0.163 ppm) and zinc (18.46 ppm) occurred in Grenada Reservoir. Mercury was observed in similar concentration in fish from most watershed divisions (average 0.284 ppm) but was much lower in the Yalobusha River (0.065 ppm). DDT and metabolites (summed) were observed in highest average concentrations in fish tissues from the Yalobusha River upstream of the debris jam (327 ppb). Lowest average SDDT concentrations were observed from fish in tributaries, either upstream (14 ppb) or downstream (5 ppb) of the debris jam, and in the main body of Grenada Reservoir (20 ppb). PCBs were never detected in fish from Grenada Reservoir or watershed tributaries, and were only rarely detected from fish of the Yalobusha River. The persistent pesticide toxaphene was detected in only one fish, and chlordane, the third most common cause for advisories in the U.S., was never detected in fish during our study.
Spatial technologies assessing rural septic systems (STARSS)
Year: Authors: O'Hara C.
Over one third of Mississippi residents depend on septic systems to dispose of household waste water. Septic system failure is particularly a problem in fast growing rural areas. The Spatial Technologies Assessing Rural Septic Systems (STARSS) project plans to locate and map these problems using mobile computing, field mapping, remote sensing, and GIS technologies. In many cases, the locations of rural septic systems are poorly mapped and only known to workers. The STARSS pilot project effort is directed at developing a GIS/GPS field application for septic system mapping, inspection, and fault reporting. The intended product is a simple, user friendly, portable application to standardize the locating and mapping of the septic system while providing attribute information of the location. The custom application being developed will leverage PDA, GIS, and GPS technologies. The application will integrate selected basemap information downloaded from a server in a seamless application for the user and will have custom menus and interfaces that meets the field mapping needs of the application. The STARSS project is funded by the MSU GeoResources Institute (GRI) and Mississippi’s Water Resources Research Institute’s (WRRI) Southeastern Regional Small Drinking Water Systems Technical Assistance Center through a U.S. Environmental Protection Agency grant.
Chemical oxidation priming for enhancing petroleum hydrocarbon removal in soils by biological treatment
Year: Authors: Zappi M., Wang W., Hernandez R., Kuo C.H.
Petroleum Hydrocarbons represent one of the most predominant forms of pollution contaminating soils worldwide. Sources of this contamination include accidental and intentional releases during production, transportation, and storage. Biological treatment has gained significant stature as an economic means of removing petroleum products from soils. However, removal of mid-weight fractions, primarily polycyclic aromatic hydrocarbons, is kinetically slow due to difficulties with strong sorptive bonds and induction of key oxygenases required for degradation. Research at Mississippi State University has focused on the combining of chemical oxidation and biological treatment into a new, innovative "hybrid" process. The concept being that chemical oxidizers are very adapt at cleaving aromatic rings, while having difficulty with removal of straight chain products. Biological treatment is just the opposite, it is quite capable of degrading straight chain compounds, but has problems with the degradation of ringed compounds. Recent results indicate that initially treating soils with biological treatment until the rate of degradation is kinetically slow can be enhanced by a short period of chemical priming using ozone or Fenton’s Reagent; later, followed by the re-establishment of biological treatment. One series of experiments initially removed over 70% of the total petroleum content via biological treatment. After that initial phase, Fenton’s Reagent was applied removing an additional 20%, then biological treatment was re-started removing an additional 8%. It is hypothesized that the chemical oxidation step removes a portion of the residual petroleum, plus degrades some of the recalcitrant fractions into smaller, more soluble compounds for subsequent removal via the re-started biotreatment. It is also speculated that the application of the oxidizers to the soil disrupts the adsorptive capacity of the soil toward the petroleum products, via oxidation of organic matter, making the organic compounds more susceptible to subsequent biological treatment.
The use of phosphates to reduce lead mobility at military small arms training ranges
Year: Authors: Bricka R.M.
The primary goal of the United States Military is to train and equip troops to maintain military readiness to defend the United States and its interests. Small arms range (SAR) training represents a major element in keeping the military ready to accomplish this mission. Projectiles utilized as part of SAR training have accumulated in the soil at the SARs as a result of many years of use. These projectiles are composed of toxic metals, such as lead and copper. The projectiles, with weathering, transform from a relatively insoluble elemental form of metal to an oxidized or ionized complex. This transformation increases the mobility of the metal which may allow it to migrate to surface and ground water sources. Due to the toxicity associated with the metals, the SAR may pose a threat to humans and the environment. Recent studies show that the treatment of the soil with phosphate-based binders may react with the metals, which results in lowering the solubility of the lead and other metals. The phosphate based-binders react with the metal ions, such as lead, to form insoluble metal phosphate complexes called pyromorphites as shown in equation 1. 10M2+ + 6H2PO4 - + 2OH- > M10(PO4)6(OH2) + 12H+ Eq (1). Several types of phosphate binders can be used to form the desired pyromorphites, however, the kinetics of the reaction depend on the phosphate complex. This may be due to the ability of the specific binder to mix efficiently in the contaminated soil or due to the reactive nature of the specific form of phosphate applied to the site. This paper presents the results of a study to investigate the effect of phosphates on the lead contained in soils collected at military SAR training areas. Laboratory evaluations consisted of adding various phosphates at different dosages to SAR samples. After treatment the soils were subjected to a series of leaching tests. The result of laboratory effort as well as the planned field activities will be presented.
Phosphorus inactiviation and odor control in animal waste lagoons, growing facilities, and natural surface water
Year: Authors: Lind C.B.
Nutrient Inactivation, specifically Phosphorus Inactivation is the interception and chemical precipitation of phosphorus from the soluble reactive form into an insoluble un-bioavailable form. The algae responsible for eutrophication of surface waters need their nutrients soluble-they have no roots to chemically solubilize and absorb nutrients. Precipitation of phosphorus with aluminum and iron compounds has been an integral part of lake restoration since 1968. Over 200 lakes have been treated to eliminate P as a nutrient. Using the same chemistry animal wastes can be treated to precipitate P prior to final disposal, or better reuse. Ferric iron sulfate has the added benefit of precipitating the odiferous, toxic, and corrosive hydrogen sulfide (H2S) from sludges and liquid streams. Hydrogen sulfide can also be effectively controlled by sodium nitrite. The use of alum or iron in waste streams will also control struvite. These chemicals, their applications and case studies will be presented in an overview format.
The civil works program and planning process: A green corps in 2003
Year: Authors: Johnson N.
The Federal objective of water and land resources planning remains to contribute to National Economic Development (NED) consistent with protecting the Nation’s environment. The U.S. Army Corps of Engineers planning process is grounded in the economic and environmental Principles and Guidelines promulgated in 1983. National economic development (NED) plans and national ecosystem restoration (NER) plans attempt to maximize net benefits and balance economic and environmental objectives. Today, the planning program of the Corps is pursuing a multifaceted approach of additional education, leadership development, and model upgrades to produce better planning products. The Corps environmental restoration mission is expanding and expenditures for environmental investment are increasing. The Chief of Engineers, in recent testimony on the Corps Fiscal Year 2004 Civil Works Program, stated that almost 20 percent of the Civil Works budget supports the environment. This amounts to approximately $800 million annually being spent on environmental restoration, mitigation, the regulatory program, and remedial cleanup programs. The Corps has reaffirmed its commitment to the environment by formalizing a set of Environmental Operating Principles applicable to all decision making and programs. The Vicksburg District’s reforestation efforts (in February 2003, the District celebrated the planting of 20,000 acres of bottomland hardwoods) are one example of our implementation of the environmental operating principles. National partnering agreements with the Environmental Protection Agency, the U.S. Fish and Wildlife Service, the Nature Conservancy, and Ducks Unlimited also substantiate the principles. The total impact of these environmental positives promotes balance and sustainability in Corps water resources projects.
Development of a program for improved flood preparedness, warning, and response in the Limpopo River Basin of Botswana
Year: Authors: Turnipseed D.P.
During 1999-2000, many parts of the Southern African Region experienced devastating floods, most of which occurred from December 1999 through March 2000. Rainfall accumulations during February 2000 in Botswana have been estimated in some areas to have been greater than 1,000 millimeters (39.4 inches) in one storm event, which is more than twice the average annual rainfall. Many lives were lost; tens of thousands of people were displaced from homes, and more than $285 million of damage was reported. The local water-related agencies in the Republic of Botswana were not well equipped to respond to these rapidly occurring major flood events. At the time of these floods, there was limited coverage of hydrological and meteorological monitoring stations in the Limpopo River Basin in Botswana, and only three stations provided near real-time reporting capability. In addition, the local data-collection agencies had no capacity to convert the raw data collected by Botswanan hydrologic and meteorologic agencies into the type of information needed by the Republic of Botswana National Disaster Management Office (NDMO) to prepare, warn, or effectively respond to these disasters. The information available to the NDMO decision makers during this flooding could have been significantly improved with the installation of additional, strategically placed, near real-time river and rainfall monitoring stations, along with training and the infrastructure to support rainfall/runoff modeling. In response to these floods the U.S. Geological Survey (USGS) in cooperation with the U.S. Agency for International Development, Regional Center for Southern Africa (USAID/RCSA) developed a plan to improve flood preparedness, warning, and response in the Limpopo River basin in Botswana. The project, which was entitled "Village Flood Watch: A Program for the Improved Preparedness, Warning and Response in the Limpopo River Basin in Botswana," was made possible by a grant from the USAID/RCSA located in Gaborone, Botswana. In addition, the USGS worked closely with many national and international agencies to complete this project: <ul><li>European Organization for the Exploitation of Meteorological Satellites</li> <li>Republic of Botswana Department of Meteorological Services</li> <li>Republic of Botswana Department of Roads</li> <li>Republic of Botswana Department of Water Affairs</li> <li>Republic of Botswana National Disaster Management Office</li> <li>Southern African Development Community</li> <li>World Meteorological Organization</li></ul> This program provided hydrological and meteorological parameters and a pilot hydrological runoff model that will assist the Botswanan governmental agencies in the propagation of hydrological runoff models in all the subbasins of the Limpopo River Basin for use in future flooding disasters. This report presents an overview of all phases of the project, along with selected data about gages within the Limpopo River Basin.
Channel changes along a modified floodplain: Leaf River, Mississippi
Year: Authors: Mossa J.
As part of a larger study involving a geomorphic assessment of the Pascagoula drainage in Mississippi, this paper discusses the preliminary interpretations of channel changes on the Leaf River from a cross-sectional perspective, based primarily on historic USGS data. The continuous gage stations on the Leaf River were evaluated for trends indicating aggradation or degradation using discharge summary data. Several stations have data collected before 1940. Historic cross sections were plotted at both these continuous and a few other discontinuous gage locations with sufficient data. Research on spatial patterns and temporal relationships of channel changes is important because channel instability has numerous ramifications to the environment and private and public properties. Elucidating and quantifying these relationships can assist in defining and refining state regulations regarding floodplain activities, including those associated with deforestation, agriculture, mining and development. Of the four continuous locations on the Leaf River, the two upstream sites show some (Collins) to pronounced (Hattiesburg) decreases of about 1 and 2m in mean bed elevation and 0.5 and 4m in thalweg elevation. Hattiesburg also shows an increase in maximum depth of about 1.5m, changing most rapidly during the 1970s, and stabilizing since then, possibly due to in-channel mining in the Bowie River, a tributary that joins it just upstream of the gage site. Other types of geomorphic changes are not pronounced and inconsistent. The two downstream sites (New Augusta, McLain) show increases in mean bed elevation of 1m and thalweg elevation to 3m, increases in width and larger increases width-depth ratio. This study also characterizes several episodes of possible lateral migration and other changes identified from plots of historic cross sections. Several possible changes are listed, and through continuing work more evidence and analysis will help to establish which of these occurred and to gather further information about the timing and magnitude of these possible changes in planform and profile.
Hydrologic controls on bald cypress growth in seasonally inundated wetlands
Year: Authors: Davidson G., Laine B., Galicki S., Threlkeld S.
Several studies have reported a correlation between precipitation and the thickness of annual growth rings in bald cypress, including trees growing in saturated sediments where growth should not be water-limited. In wetlands where bald-cypress roots remain partially or fully immersed throughout the year, the growthprecipitation correlation may be a result of increased nutrient availability following precipitation and subsequent runoff into the wetland. Nutrients may be delivered by flushing the root zone with nutrient-rich water, or attached to sediments washed into the wetland during precipitation events. Both possibilities are being investigated at Sky Lake in Humphrey’s County, Mississippi. Sky Lake is an oxbow-lake wetland formed by the ancestral Mississippi River. Surface outflow from the lake is ephemeral, with seasonal flow through Wasp Lake into the Yazoo River. Flow periodically reverses when the Yazoo River is high. Backflow from the Yazoo River can raise water levels in the vegetated fringe of Sky Lake in excess of 4 m, creating the potential for reversals in subsurface flow in the root zone. Water chemistry, isotopic composition and hydraulic head are being monitored using a series of nested piezometers completed in and below the root zone along an elevation transect beginning at the perennial low water line. Evaporation of lake water during the drier summer season is evident from enriched 18O values in lake water relative to precipitation and stream inflows. Both head and isotopic data collected from the piezometers during the Fall of 2002 suggest that shallow groundwater flow is toward the lake as expected when the lake level is low. Monitoring through the winter will allow evaluation of possible flow reversals when the lake level is high. The influence of sediment influx on tree growth is being evaluated by measuring sedimentation rates in high and low flux areas of Sky Lake, and the width of annual growth rings in bald cypress growing in these areas. Preliminary data suggests that bald cypress grow more rapidly when sedimentation rates are higher.
Development of watershed and subwatershed boundaries for Mississippi
Year: Authors: Turnipseed D.P., Clair, II M.G.
Successful implementation of federal regulatory programs such as the Clean Water Act and the Safe Drinking Water Act mandates that federal, state, and local agencies, as well as scientists and consultants in the private sector, have appropriate hydrologic data to make informed decisions, do analyses, and address water-quality issues on a watershed basis. These hydrologic data are required to accomplish such tasks as establishing and implementing Total Maximum Daily Loads (TMDLs) and source-water protection. Drainage-area data, at the watershed scale, are not currently available in many states. Engineers need drainage-area data to design various hydraulic structures such as bridges, culverts, storm-sewer systems, and intake and effluent discharges for various industrial, manufacturing, and processing plants. Accurate drainage-area data is needed by regulators and managers to assess the effects of proposed water use, design and develop flood-control structures, measure and mitigate water quality, and develop surface-water models to assist in appropriate waterresource management decisions. In 2003 the U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Agriculture/Natural Resources Conservation Service (NRCS), the U.S. Department of Agriculture/Forest Service (USFS), the Mississippi Department of Environmental Quality/Office of Pollution Control (MSDEQ-OPC), and the Mississippi Automated Resources Information System (MARIS), will complete development of a watershed and subwatershed map of Mississippi attributed with 10- and 12-digit hydrologic unit codes (HUC). The base data for this map are 1:24,000-scale, 7.5- minute topographic quadrangle sheets. These data will be made available as hardcopy, CD-ROM, or direct view and download through the USGS Internet portal at: http://ms.water.usgs.gov/ These watershed and subwatershed boundaries provide a standardized dataset for the state of Mississippi for use by water-resource managers, engineers and planners in locating, storing, retrieving, and exchanging hydrologic data. Also, these data, in a digital form, can be used in surfacewater steady- and unsteady-flow modeling, runoff modeling, cataloging water-data acquisition, the computation and estimation of flood frequency, and low-flow duration, as well as many other waterquality and water-use projects. This report presents information on methodology and development of drainage and hydrography in the form of USGS hydrologic boundaries of water-resources regions, subregions, basins (formerly called accounting units), subbasins (formerly called cataloging units), watersheds, and subwatersheds.
Project integration for basin management: Mississippi’s Upper Pearl River Basin
Year: Authors: Jones D., Ballweber J.A., Griffin K., Steil J., Tagert M.L.
Watershed management is a complicated undertaking. Due to funding realities, successful integrated watershed or basin management requires the coordination of numerous "projects" funded through various existing federal and state programs (i.e., source water protection, nonpoint source water pollution, etc.). The process of developing project ideas and proposals provides an ideal opportunity to organize and expand informal cooperative basin or watershed management partnerships. As projects are funded the partnerships can be formalized as Watershed Advisory Groups. This presentation provides a status report on the progress of this approach in Mississippi’s Upper Pearl River Basin.
Conserving Mississippi’s Freshwater Biodiversity
Year: Authors: Hicks M.B.
The southeastern United States harbors a rich diversity of freshwater species and ecosystems. In particular, Mississippi contains a spectacular diversity of aquatic plants and animals throughout its many watersheds, from coastal black water systems to lower Appalachian Tennessee River systems. Certain incompatible human uses of Mississippi’s natural resources pose potential threats to this natural heritage, and many entities, including non-profit organizations, governmental agencies, local community groups and private sector companies are increasing their efforts to protect water quality, quantity and biodiversity within the State. Limited resources, however, require their efforts be carefully planned and focused to increase the probability of successful conservation and thus have a positive impact on aquatic natural resources. The Nature Conservancy (TNC) has been active in biological conservation of Mississippi’s natural resources for many decades. In recent years, the Mississippi (MS) Chapter of TNC has focused resources and efforts on protecting and restoring the biodiversity of Mississippi’s freshwater ecosystems. Through a process called Conservation by Design, freshwater conservation areas of biodiversity significance have been identified and prioritized and the development of plans to conserve and or protect these areas is underway. The next steps for the MS chapter of TNC will be to implement these conservation plans, measure the success of our conservation efforts and continue to revise the conservation plans as data and information become available. A major factor in the success of our conservation efforts will rely upon how well the community is engaged in the process, partnering with local, state and federal government agencies, using scientific data as the foundation of the process and obtaining adequate funding for the planning and implementation of the conservation strategies.
Turbidity estimated sediment loads at Deer Creek east of Leland, Mississippi
Year: Authors: Runner M.S.
The Mississippi District of the U. S. Geological Survey (USGS), in cooperation with the Mississippi Department of Environmental Quality-Office of Land and Water Resources (MDEQ-OLWR), the U.S. Fish and Wildlife Service (USF&WS), and the Yazoo Mississippi Delta Joint Water Management District (YMD), began collecting stream stage, discharge, turbidity and other water-quality data, and suspended-sediment concentration data at Deer Creek East of Leland, Mississippi, in December 2001. The purpose of this study is to collect data for the evaluation of the aquatic health of Deer Creek as part of the Deer Creek Restoration Project. This paper presents the results of an analysis to test the use of continuous-turbidity data as a surrogate for suspended-sediment concentrations. Sensors that measure the bulk optical properties of water, such as turbidity, have been used to provide a continuous time series estimate of suspended-sediment concentrations with a quantifiable certainty (Schoellhamer, 2001). Christensen, and others (2000) used simple linear regression to develop a site-specific model using turbidity to continuously estimate suspendedsediment concentrations. The generated regression equation explained about 93 percent of the variance in suspended-sediment concentrations.
Implementation of a QA/QC program for surface water quality monitoring activities in Mississippi: Quest for reliable data
Year: Authors: Hicks M.B., Loch D.D., Pigott K.R.
The Mississippi Department of Environmental Quality (MDEQ) has developed a comprehensive Quality Assurance/Quality Control (QA/QC) program for all components of its surface water monitoring programs. A statewide project to monitor and assess Clean Water Act Section 303(d) listed streams and develop an Index of Biological Integrity (IBI) was used as a springboard for this program. The following QA/QC procedures were developed and implemented during the 303(d)/IBI project: preparation of a Quality Assurance Project Plan (QAPP), inclusion of Quality Control activities and Corrective Actions, and procedures for developing and evaluating method performance characteristics. The QA/QC program is generally structured to isolate, identify and correct problems in either process or design that produce error and increase variability. Quality Control activities are focused upon each step of the assessment process. Several QC activities used to evaluate either particular methods or results for this project included the following: field and laboratory audits, duplicate and repeat sampling, calculation of percent sorting efficiency, pickate re-checks, taxonomic reidentifications, 100% re-checks of data entries, and re-calculation of metrics. The end result will ensure that the discrimination efficiency of the index for the 303(d)/IBI project is acceptable for any waterbody or region in the state of Mississippi. MDEQ intends to continue to utilize and further develop this QA/QC program during future surface water monitoring activities. Consistently following QA/QC procedures will produce reliable data that will be used to make sound biological assessments.
The EPT complex (Ephemeroptera, Plecoptera, and Trichoptera) associated with headwater streams at Camp Shelby training site in South Mississippi
Year: Authors: Wilberding A.L., Howell F.G.
As immatures, mayflies, stoneflies and caddisflies are considered pollution sensitive insects and make up the Ephemeroptera-Plecoptera- Trichoptera (EPT) Index, one of the metrics often used to characterize the "environmental health" of streams. The number of distinct taxa within these orders determines the EPT Index value of a sample collection; the higher the index value, the better the quality of water. We have been using EPA’s Multi- Habitat Approach to evaluate the macroinvertebrate communities associated with the headwater streams at Camp Shelby Training Site in south Mississippi since 1997. In our study of seven of these streams, we have shown that the EPT species complex is reasonably consistent in composition across streams and seasons. In total numbers, the EPT complex accounts for six to 14% of the macroinvertebrates collected by this methodology, depending on the collection. Approximately 62 EPT species have been identified in the collections. Across streams and seasons, mayflies have been dominant (39 to over 50%), while the number of Trichoptera species is generally a close second (33 to 40%), and Plecoptera have been sparsely represented, mostly by a single genus - Perlesta. Commonly occurring mayflies include Leptophlebiidae, Baetidae, and Stenonema exiguum. Trichoptera are represented mainly by the genera Chimarra, Hydropsyche, Cheumatopsyche, and Polycentropus. Our analyses of these collections, including the use of the EPT metric, indicate that the macroinvertebrate associations found in these streams are typical of the eco-region.
Expanding the basin approach: An update on projects and progress
Year: Authors: Ballweber J.A., Griffin K.C.
Since 1998 the Mississippi Water Resources Research Institute (MWRRI) has partnered informally with the Pearl River Valley Water Supply District (PRVWSD) to coordinate with the Mississippi Department of Environmental Quality (MDEQ) to organize a voluntary Upper Pearl River Watershed Advisory Group (WAG). The WAG’s primary goal would be to expand on or enhance MDEQ’s statewide Basin Approach to Water Quality Management in the Upper Pearl River Basin. Different offices and departments at MDEQ have been very supportive of this effort and extremely helpful in identifying assorted funding sources for different components of the overall effort. As a direct result of this partnership approach, several independent but interrelated projects have been initiated using the Upper Pearl River Basin as a demonstration area. This presentation discusses relevant current and pending projects and their status. In addition, next steps for this growing effort will be presented.
Increasing communications among watershed stakeholders
Year: Authors: Oldham L.
Watershed Forum Roundtables assemble disparate stakeholders for dialogue, networking, and education to enhance local watershed initiatives and to communicate watershed news, programs, and resources. The goals are facilitated cooperation between the public and private sectors, and improved advocacy of water quality and quantity issues in government agencies. A group of private and public sector entities convened the first Mississippi Watershed Forum Roundtable in September, 2001. Education was provided on watershed topics, and various watershed protection success stories from around the state were presented. An issues panel from industry, local government, environmental organizations, agriculture, and state regulatory agencies discussed water quality and quantity issues from their perspectives. Breakout sessions considered various protection efforts working, or not working at the local level, needed improvements to current efforts, and future directions for the state. The participants stressed more interagency coordination and cooperation, increased funding for initiatives, increased local government and industrial awareness, and increased education on watershed issues. Most participants appreciated the opportunity to network with other stakeholders. Over two thirds of the participants felt the training workshops and breakout discussions were beneficial. Ninety-six percent of the evaluations suggested the Roundtable be repeated either annually or biannually. Regional Roundtables are being developed, and the next statewide Roundtable is planned for February, 2003.
Evaluation and development of Mississippi’s instream flow program: A cooperative effort
Year: Authors: Riecke D.
Historically, Mississippi has relied heavily on groundwater resources instead of surface water. The state is more heavily dependent on groundwater than any other state. Groundwater accounts for 73% of the total water used and 89% of the public supply need. Mississippi is the second most rainfall intensive state (48-66 inches/year) in the nation. Water use intensity and efficiency are relatively low. The Mississippi Department of Environmental Quality (MDEQ) has sole responsibility for determining minimum stream flows. Until 1994, Mississippi statutes defined "established minimum flow" as the average stream flow rate over seven consecutive days that may be expected to be reached as an annual minimum no more frequently than one year in ten. This is commonly known as 7Q10 and was the only method that MDEQ could use to establish baseline flows. Problems developed due to the realization that it was not appropriate to use 7Q10 on any stream that had an altered or regulated hydrologic regime. If a 7Q10 flow could not be calculated, MDEQ could not set any aquatic base flow. MDEQ was concerned that they could not legally defend the validity of using 7Q10 to establish base flows in tidally-influenced rivers. The Mississippi Department of Wildlife, Fisheries and Parks (MDWFP) contended that use of 7Q10 was seriously outdated since it only recognized one instream flow need - maintaining water quality. Prolonged 7Q10 flows would decimate fishery resources. Fortunately, increased frequency of such low flow events rarely occurs in Mississippi because surface water use is minimal. MDWFP recommended that all instream flow needs should be recognized and considered in determining minimum stream flows. All baseline stream flows should be sufficient to fully support every designated use. In 1994 Section 51-3-3 of the Mississippi Code of 1992 was amended to allow the use of other accepted scientific methodologies to establish instream flows. MDEQ is to consider all consumptive and nonconsumptive water uses and consult with MDWFP to establish minimum streamflow rates. Both agencies consider the new law a positive first step in fostering increased coordination and cooperation. The National Instream Flow Program Assessment project revealed that the only strong element in Mississippi’s instream flow program is the legal component. Mississippi’s overall instream flow program is hampered by a lack of funding and personnel specifically designated to examine flow problems and issues. Collection of vital biological, hydrological and physical data to build an effective instream flow program has not occurred. Perhaps this is due to limited agency resources and a perceived lack of urgency and importance. Mississippi, blessed with an abundance of water, has only recently experienced isolated water shortage problems. Several opportunities exist to strengthen Mississippi’s instream flow program. Since the legal component is strong, and little else exists, it is important to foster a greater appreciation of this authority among agency resource personnel. A comprehensive summary of administrative policies, procedures and state laws would help resource personnel understand their legal responsibilities and coordinate their actions. This could be accomplished by funding the development of an "Opportunities to Protect Instream Flow in Mississippi" document. Aquatic resources would benefit from the use of other methodologies to establish base flows that mimic the natural hydrograph. Since staffing, funding and emphasis will remain static for the immediate future, MDEQ and MDWFP personnel should employ desktop methods to establish higher baseline flows. Since surface water use is currently small, MDEQ and MDWFP should file for and reserve instream water rights for fish and wildlife resources prior to the intense competition that usually arises as water supplies become limited. This will establish priority of use and reserve water for a variety of instream uses. Mississippi’s instream flow program is just beginning and has a long journey ahead of it. The programs of other states illustrate the importance of considering various methods to provide sufficient stream flow for all anticipated uses.. MDEQ and MDWFP are working to develop an effective instream flow program that adequately supports a variety of uses and sustains biologically viable fish and wildlife populations for enjoyment by all citizens.
An introduction to the Southeastern Small Drinking Water Systems Technical Assistance Center
Year: Authors: Cox S.
Mississippi’s Water Resources Research Institute (WRRI) received funding from the U. S. Environmental Protection Agency to establish a Southeastern Regional Small Drinking Water Technical Assistance Center (SE-TAC). The purpose of the SE-TAC is to provide technical and instructional support for small drinking water systems in the southeastern United States who have experienced increased technical, monitoring, and reporting requirements mandated by the Safe Drinking Water Act as amended in 1996, 42 U.S.C. §§ 300f et seq. The following eleven (11) states are included in the southeastern region: Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee and Texas. A Regional Advisory Board provides a broad regional perspective of small drinking water systems’ priority needs, avoids duplication of effort, and focuses the SE-TAC’s activities and resources on issues inadequately addressed by existing programs. The Regional Advisory Board: <ul><li>Identifies the SE-TAC’s project priorities and approves the proposal format and grading criteria;</li> <li>Helps distribute Requests For Proposals for the regional grants competition, and;</li> <li>Grades the project proposals.</li></ul> The following five (5) states were invited to serve on the Regional Advisory Board: Alabama, Louisiana, Mississippi, North Carolina, and Texas. Each of these states has three (3) seats on the Board allocated as follows: <ul><li>One (1) seat for the state’s rural water association or equivalent organization;</li> <li>One (1) seat for a representative from the state’s primacy agency, and;</li> <li>One (1) seat for a technical assistance provider including but not limited to Community Resource Group/Rural Community Assistance Project, or section of the American Water Works Association or similar organization active in assisting small community water systems in that state.</li></ul> This poster highlights the SE-TAC’s activities in 2001-2002.
Water quality under natural conditions: Comparisons of urban, rural and reference watershed in North Mississippi
Year: Authors: Lizotte, Jr. R.E., Moore M.T., Cooper C.M., Holland M.M.
Objectives of this study were to examine and compare physical, chemical, and biological water quality parameters in three north Mississippi hill land stream watersheds having distinctly different land uses. As part of the Demonstration Erosion Control (DEC) Project in the Yazoo Drainage Basin, routine monitoring of water quality is performed in seven north Mississippi hill land stream watersheds which have been rehabilitated to control flooding, reduce erosion and stabilize stream channels. Evaluation of water quality improvement in these rehabilitated watersheds presents difficulties due to the lack of both long-term water quality data before rehabilitation and expected maximal recovery. The use of reference streams under natural conditions as surrogates for comparison has become increasingly valuable. Three creeks were monitored at three sites in March, June, September and December from 1998 to 2000. Burney Branch Creek is an urban land use stream that flows through the city of Oxford, Mississippi and has the highest watershed development. Toby Tubby Creek is primarily a rural land use stream that is buffered by a large forested wetland. Bay Springs Branch is a spring fed reference stream located in Holly Springs National Forest and flows through the University of Mississippi Field Station and wildlife refuge. Comparisons of temperature, dissolved oxygen, and suspended solids values among the three streams were not significantly different. Comparisons of overall conductivity measurements and dissolved solids concentrations showed Burney Branch > Toby Tubby > Bay Springs Branch. Overall comparisons of nutrient data showed Burney Branch > Toby Tubby Creek and Bay Springs Branch and overall microbial analyses showed Burney Branch > Bay Springs Branch. Seasonal interactions were observed for nitrate-N and fecal coliform data. Seasonal nitrate-N concentrations showed Burney Branch Creek > Toby Tubby Creek and Bay Springs Branch in March, Bay Springs Branch in June, and Bay Springs Branch > Toby Tubby Creek in September. Seasonal fecal coliform counts showed Burney Branch Creek > Bay Springs Branch in June and Toby Tubby Creek > Bay Springs Branch in December. Despite widely different land uses surrounding these streams, comparisons of overall water quality indicated Bay Springs Branch had moderately better water quality than Toby Tubby Creek and significantly better water quality than Burney Branch Creek.
The effects of best management practices on agricultural runoff in the Mississippi Delta, 1996-2000
Year: Authors: Rebich R.A.
The U.S. Geological Survey has collected streamflow and water-quality samples at nine agricultural runoff sites in three oxbow lake watersheds in Sunflower and Leflore Counties, MS. This effort is part of the Mississippi Delta Management Systems Evaluation Areas (MDMSEA) project, which began in April 1996. The samples were collected to characterize runoff from different agricultural settings including: one field that remained untreated; fields treated with edge-of-field best management practices (BMPs), such as slotted-board risers and filter strips; fields treated with a combination of edge-of-field and within-field cultural BMPs (within-field BMPs included cover crops and conservation tillage); and a riparian area. Since 1996, about 2,800 sediment, 890 nutrient, and 870 pesticide samples were collected by using automated samplers. Total runoff volume was also measured at six of the nine sites by using flumes, weirs, or acoustic Doppler velocity meters. The quality of the runoff was considered to be the most degraded at the untreated site, which was in conventional tillage for the study period. This statement is supported by the fact that the highest concentrations of sediment, nutrients, and pesticides were measured in runoff samples from the untreated site. Annual runoff totals, sediment loads, and some of the nutrient loads were also the highest at this site. The edge-of-field BMPs, which included slottedboard risers and filter strips, by themselves did not improve runoff quality substantially. This statement is supported by the fact that concentrations and loads of sediment and nutrients were similar or actually greater at these sites than at the untreated site. However, sediment loads were reduced by about 30 percent when temporary boards were in place at the slotted-board riser site during the nongrowing season months. Also, since 1996, about 1 foot of sediment was trapped in front of the permanent boards at the slotted-board riser site, and gully erosion was minimized. Sediment, nutrient, and pesticide concentrations and loads were significantly lower where cultural practices, such as conservation tillage and winter cover, were utilized. For example, sediment, nitrate, total phosphorus, and fluometuron (a cotton herbicide) loads were 78, 79, 46, and 71 percent lower, respectively, at the conservation tillage/winter cover site than at the untreated site. Data from the riparian area sites indicate how efficiently an undisturbed riparian area can filter sediment and process nutrients and pesticides from agricultural runoff. Concentrations of sediment, nutrients, and pesticides were lower at the riparian area sites than at the other six runoff sites.
The influence of reduced rainfall seasons on the runoff and leaching losses of mobile agricultural pesticides and on their runnoff/leaching ratios
Year: Authors: Southwick L.M., Grigg B.C., Fouss J.L., Kornecki T.S.
From 1985 to 1992 we studied runoff and leaching losses of soil-applied pesticides (mostly herbicides) from large plots ($ 2 ha) on Commerce clay loam Mississippi River alluvial soil in southern Louisiana (Southwick et al., 1990a, 1990b, 1997). This is an area with typically 1500 mm of annual rainfall and with a runoff event from agricultural land about every week. Under these conditions we observed that 1-3% of applied atrazine and metolachlor [mobile pesticides: water solubility > 30 mg/L; Koc # 200 mL/g (Hornsby et al., 1996)] left the field in runoff and more than an order of magnitude less left the field by leaching through the soil (Tables 1, 2). From these plots we measured 1.5-5.1 times as much water volume in runoff as in leachate, and 7.7-91 times as much herbicide in runoff as in leachate. Since 1994 we have been studying runoff and leaching losses of the mobile chemicals atrazine, simazine, and metolachlor from 0.21 ha plots on Commerce clay loam. Here we compare our results for 1995-97, with typical rainfall patterns like our earlier studies, with our earlier large-plot work (1987-92), and contrast our 1995-97 results with those from the exceptionally dry years 1998- 2000. The large change in rainfall pattern for the latter period led to great differences in runoff and to small differences in leaching behavior of the studied herbicides.
A multiparameter gaging station on the Escatawpa River near Orange Grove, Mississippi
Year: Authors: Stocks S.J., Storm J.B.
On August 21-22, 2001, the U.S. Geological Survey (USGS) constructed a streamgage on the Escatawpa River at Interstate 10 near Orange Grove, Mississippi. The Escatawpa River is tidally affected which influences water quality, flow rate, and flow direction. The gaging station is equipped with multiple instruments that continually monitor tidal stage, stream velocity, salinity, specific conductance, and water temperature. Data from the site are transmitted every 4 hours via GOES satellite to the USGS office in Pearl, Mississippi, where they are archived and presented on the USGS real-time web page. To accommodate the multiple instruments, a unique mount was designed to hold two acoustic Doppler velocity meters (ADVM) and a waterquality sonde. The mount is connected to a rolling carriage that travels along a vertical aluminum Hbeam attached to a near-bank bridge pier. Instruments can be raised and lowered at the gage and serviced by boat. The velocity meters are positioned on opposite sides of the water-quality sonde, perpendicular to the stream flow, with one meter facing horizontal and the other facing downward at 45 degrees from horizontal. The ADVMs measure stream velocity vectors as well as water temperature. The water-quality sonde measures stage, specific conductance, and water temperature. Salinity is computed from specific conductance by using a linear regression coefficient. Tidally affected streams can have multiple flow regimes including positive, bi-directional, and negative flows. By positioning one ADVM downward at 45 degrees, the velocity vectors are measured and averaged over an angled column of water that extends to the bottom of the channel bed rather than at a single depth. Average crosssectional velocities are computed from acoustic Doppler current profiler discharge measurements and compared to instantaneous ADVM velocities. A velocity regression equation is used to compute continuous discharge at this site.
Integrated ground-water database
Year: Authors: Welch H.L.
The U.S. Geological Survey (USGS) has developed an integrated ground-water database to provide water-quality data, potential point and non-point pollution sources, and other relevant data to water resources scientists and managers. The data are located in a Microsoft Access database which contains ground-water-quality data from the Mississippi State Department of Health and the USGS, ground-water-level data from the Mississippi Department of Environmental Quality (MDEQ) and the USGS, and electric well log information from the USGS files. The USGS is in the process of incorporating scanned electric log images and pesticide data from the MDEQ into the database. A geographic information system application will be developed that incorporates tabular data, mapbased data, and graphical data from many sources to provide an array of information to the public to facilitate water management and protection.
Mississippi Department of Environmental Quality’s surface water monitoring program
Year: Authors: Hicks M.B., Thomas J.V.
The Mississippi Department of Environmental Quality’s Surface Water Division (SWD) is responsible for the conservation of the quality of the surface water of Mississippi for public use by the citizens of the state of Mississippi. This responsibility coupled with legislative mandates set forth by the Mississippi Water Pollution Control Act and the Federal Clean Water Act serve as the main purpose for development and implementation of the Surface Water Monitoring Program (SWMP). The purpose of this paper is to outline the elements of MDEQ’s SWMP. The key elements include clearly defined objectives and an outline of the overall strategy to be used to meet these objectives. A conceptual model of the Program involves two major components: Ambient Monitoring Networks and Program Support Monitoring Activities. The former component addresses general water quality assessment of status and trends and the later component addresses specific monitoring and assessment needs of other SWD programs (i.e. Total Maximum Daily Load Program, Standards Program, Non-point Source Program, etc.). Ecological indicators used in the SWMP consist of a suite of physical, chemical and biological parameters. Data collected for the SWMP are housed in an internal database and will in the future be available to the public through MDEQ’s Surface Water Information Management System (SWIMS) and U.S. EPA’s Storage and Retrieval System (STORET). Routine water quality assessments are made on these data by SWD personnel and are reported in the State’s 305(b) Water Quality Report to Congress every two years. In addition, internal reports are generated and are available to the public.
An overview of Mississippi military departments bioassessment programs at Camp Shelby and Camp McCain training sites
Year: Authors: Howell F., Wilberding A., Ducote E.
As part of its agreement with the US Forest Service for permission to use selected national forest lands for training activities, the Mississippi Military Department incorporated aquatic biomonitoring (stream bioassessment) into its environmental evaluation programs in 1997. The primary purpose of the program is to monitor impacts of training activities on biological integrity of streams that exit training site boundaries. One of EPA’s Rapid Bioassessment protocols (macroinvertebrates in wadeable streams and rivers) is used as the primary data collection platform. The resulting data sets (seasonal collections from each of seven permanent sites at Camp Shelby and three permanent sites at Camp McCain) are qualitative by design; give us taxonomic lists and a variety of metrics (including biotic index, EPT, species diversity, % dominant taxon) related to the distribution, abundance, and functional roles of taxa in these stream communities. By following these metrics through time, we are in a better position to detect developing trends relating to the environmental integrity of training site lands. Additionally, the data also help us satisfy NEPA and U.S. Forest Service reporting requirements and gives us pre/post evaluation data for describing impacts related to on-going or future facilities development, such as the G. V. "Sonny" Montgomery Multiple Purpose Range Complex - Heavy (MPRC-H) and the Multiple Launch Rocket System (MLRS) and operation without extra costs.
Mississippi Museum of Natural Science: Overview of aquatic related conservation research activities
Year: Authors: Knight C.
The Mississippi Museum of Natural Science - Conservation Biology Section consists of the Mississippi Natural Heritage Program and the Research and Biological Collections Program and is focused on technical and biological issues related to the conservation of Mississippi’s biological diversity. Much emphasis has been placed on distributional patterns, demographics and environmental constraints of more than fifty aquatic or semiaquatic animal species listed as endangered by the state. Within the last five years, the Museum has performed or funded numerous applied research projects, inventories and surveys of aquatic species or species closely linked to aquatic systems. Priority species include many freshwater mussels and fishes although certain amphibians, reptiles and birds have also been targeted. Information acquired from these activities is used to facilitate conservation based land use decisions and provide technical guidance to land managers and other biologists. The Natural Heritage Program responds annually to over 750 formal requests for information related to potential impacts of development projects on endangered species. In addition, information is made available to general audiences through exhibits and educational programing. Museum visitation currently exceeds 180,000 per year.
Discharge patterns in the Pascagoula River drainage and movement patterns of Gulf Sturgeon: Timing is everything
Year: Authors: Ross S.T., Dugo M.A., Heise R.J., Slack W.T.
Gulf sturgeon (Acipenser oxyrinchus desotoi) are migratory fish, with adults moving into rivers in early spring for spawning and migrating back out into the marine environment in the late fall. Since 1997, our research group has documented the migratory patterns Gulf sturgeon in the Pascagoula River drainage of Mississippi using radio telemetry and capture data. Water temperature and stream discharge are important factors influencing Gulf sturgeon migration. The arrival of Gulf sturgeon each April at a spawning site has consistently occurred when water temperatures increased to 19.2 -21.2 C in association with pulses of higher stream discharge. Most sturgeon migrate out of summer holding areas and into salt water between September and November when water temperatures drop below 23 to 25 C and there are accompanying pulses in river discharge. Migration out of fresh water can extend into January. When declining river water temperatures are not coupled with increased river discharge, Gulf sturgeon do not migrate out of fresh water as expected. These data further support the importance of free flowing rivers for migratory species.
Soil Type and 2,4-D Leaching on a Sugarcane Watershed in Brazil.
Year: Authors: Cerdeira A., Pessoa C., Rocha A., Costa F., Shuhama I., Lanchote V., Ueta J.
The region of Ribeirao Preto, SP, Brazil, is located on the Guarani aquifer, the most important source of ground water in the South Central region of the country. The recharge area of this aquifer is located in the Espraiado watershed. The presence of sandy soil and a sugar cane crop treated with high rate of pesticides applied makes the aquifer vulnerable to groundwater contamination. The herbicide 2,4-d (2,4-dichlorophenoxyacetic acid) was among the pesticides used. To study its behavior, a gas chromatography analytical method for residue analysis was developed and 2,4-D was measured during the years of 1996 until 1999. The movement also was evaluated with simulation using the software CMLS-94-"Chemical Movement in Layered Soils". The gas chromatography analytical method resulted in a 99.9% correlation of the area in the graphics and the herbicide concentration, and indicated that it was highly effective. No residue of 2,4-D was detected in water in any year. The simulation model CMLS have indicated the leaching down to 60 cm., far from the water table, in both types of soils, "Latossolo Roxo" and "Latossolo Vermelho-Escuro" in the second year after the application when the herbicide residues would already been dissipated.
Streamflow and nitrogen and phosphorus concentrations and loads for the Yazoo River below Steele Bayou near Long Lake, Mississippi, 1996-2000
Year: Authors: Runner M.S., Coupe R.H.
In 1996, as part of the U.S. Geological Survey (USGS) NationalWater-QualityAssessment (NAWQA) Program, surface-water data collection began in the Yazoo River. The surface-water quantity and quality data that were collected are sufficient to calculate annual loads of nitrogen and phosphorus discharged from theYazoo River to the Mississippi River from 1996 through 2000.
High germicidal and low mutagenic effect of sodium hypochlorite
Year: Authors: Yang W.H., Washington A., Lawretta A.A., Yang J.R.
Sodium hypochlorite was first registered for commercial use as an antimicrobial pesticide in 1957( U.S.E.P.A., 1991). The aqueous solution of Sodium hypochlorite with 5.25% in concentration is commonly used as a house-hold bleaching agent. Sodium hypochlorite is registered with the Environmental Protection Agency for use as a sanitizing agent, disinfecting agent. The chemical has many usages in the area of food processing, laundry services, agricultural settings, gardens, animal facilities, hospitals, and human drinking water supplies ( Weber, 1997 ). Household bleaches usually contain 3% to 6% sodium hypochlorite whereas industrial and institutional bleach applications are typically 10%~12% active ( Fletcher, 2001). The mechanism of disinfection has not been completely understood, but researchers have proposed enzyme disruption, protein denaturation, and nucleic acid inactivation for such germicidal activity ( Dychdala, 1991 ). Bacteria, molds, and mildews are inhibited and killed by sodium hypochlorite ( Herndon, 1991). The use of bleach in prevention of transmissible diseases in health care have been proven to be very effective ( Spire, 1984 ). The acquired immunodeficiency syndrome virus - III/ lymphadenopathy- associated virus, was inactivated by the application of this bleaching agent ( McDougal et al, 1985 ). Sodium hypochlorite was also effective for sanitation of many other viral diseaases including african swine fever virus, equine viral arteritis virus, porcine reproductive and respiratory syndrom virus, and the african horse sickness virus (Shirai, 2000). Hypochlorite appears to have evolved from oxidative intermediates in the lysosome of eucaryotes to function not only for phagocytosis,but also for disinfection. Hypochlorite is produced in lysosome from hydrogen peroxide and chloride by the enzymatic activity of myeloperoxidase at the time of respiratory burst and at the time of biological crisis for disinfection and Table of Contents phagocytosis. In multicellular system particularly in animal, further coordination of phagocytosis mechanism in the cell with general endocrine system for adjustment of metabolic rate with the digestive activity of the organ and phagocytosis activity of the cell. Thyroid hormone secretion was increased in such occasion. by enhancement of peroxidase in the follicular cell of thyroid gland for formation of hypoiodite from iodide. Subsequently, iodination of tyrosol was achieved by thyroxin at the time of endocrine alert. Because of the increased importance of sodium hypochlorite as disinfectant and cleaner in home and environment, the biosafety of this chemical compound particular genotoxic effect of it is of great concern to many users. Current study intends to reevaluate both germicidal effect and genotoxic effect of this chemical to the test strain TA 98. In addition the strandbreaksing effect of this chemical to Simian virus 40 viral DNA.will be examined.
Weather’s role in phenological period length of Mississippi soybeans: A watered-down contribution
Year: Authors: Brown M.E., Wax C.L., Pote J.W.
The soybean crop in Mississippi is large and economically important. The state ranks 16th nationally in production of soybeans, with a 1990-2000 average of around 2 million acres planted yearly at an annual value of about $291 million (MASS, 2001). Two recent trends help account for an annual average harvest ranging from 22-26 bushels/acre over this time period: 1) the bulk of beans planted in the state is now in Maturity Groups IV and V as compared to Groups VI and VII in earlier years; and 2) this change has allowed an earlier planting date, mostly before mid-June (MCES, 2001). Earlier planting has been credited with stabilizing soybean production over the last decade (MCES, 2001). Total seasonal water need for the crop is about 20-25", reaching a maximum peak demand of near 0.25"/day (MCES, 2001). In addition to these known moisture requirements, it is also known that seedbed temperatures between 68o-86o F are needed for rapid emergence. These are well-known effects of weather on crop development, but are there critical periods of growth during which certain weather influences are more marked than during other times? What, if any, effects do weather variables or combinations of weather variables have on the time it takes soybeans to move from one developmental stage to another? Can a knowledge of these effects help make production of the crop in Mississippi more precise, dependable, and profitable? This study’s objective is to determine how weather affects the length of five phenological periods of unirrigated soybeans grown in Mississippi. Soybean data were taken from ARS plots of Maturity Groups IV and V grown at Stoneville, MS, using 113 cases of Group IV and 133 cases of Group V beans. No consideration is given to resulting yield, only to length of each phenological period. However, it must be recognized that increased yield is the ultimate objective of understanding the effect of weather on phenological period length. Twelve measured/derived weather variables are used for association with each phenological period. In other words, each phenological period is linked with the actual weather conditions that occurred during that discrete time in an attempt to isolate which weather variables affect period lengths. For that reason, this project segregated 12 weather variables for each of 1230 individual calendar periods. It is hypothesized that the lengths of different phenological stages are to some degree determined by the weather events and conditions occurring during that time. The value of this research is in the potential for optimizing productivity of soybeans in the state and consequently increasing the size and economic value of the crop. For example, if rainfall is found to be a major factor in the length of a certain growth stage, then it may be possible to manipulate water availability through irrigation at precise times to accelerate the crop’s development by shortening that particular stage. Such a management strategy could cause peak crop water demand to then be reached at a point earlier in the growing season when that demand is more likely to be met. At that point, the peak demand would be occurring ahead of the normal hot, dry weather characteristic of late summer in Mississippi. The possibility of drought stress on the crop could therefore be minimized, with a concurrent increase in quantity and quality of the crop.
The application of bacterial source tracking in Mississippi waters
Year: Authors: Ellender R.D., Wang S., Hassan W., Royston J.K., Robinson B., Rebachik D., Grimes D.J.
Bacterial source tracking (BST) is a technology in development whose goal is to define the animal of origin of intestinal bacteria that contaminate environmental waters in Mississippi. Contamination results from point (humans, cattle, pigs, horses, chicken) and non-point (storm water runoff, forests, wetlands, wildlife) sources and perhaps other poorly defined origins. Molecular methods are generally preferred over biochemical/chemical and antibiotic resistance analysis methods. Of the molecular methods, ribotyping, pulse field gel electrophoresis (PFGE), the polymerase chain reaction (PCR), and randomly amplified polymorphic DNA (RAPD) have received the most attention because they demonstrate the highest level of discrimination in the differentiation of bacterial isolates. These methods are based on the analysis of bacterial DNA, and provide unique, strain-specific fingerprint patterns. Because growth and maintenance of intestinal microflora are thought to be clonal within organisms and different animals harbor unique strains of microbes, these molecular methods are ideally suited for source tracking of fecal bacterial contamination in water. To accomplish this task, a team of seven faculty, staff and students from USM’s Colleges of Science and Technology and Marine Sciences are collecting samples from a large variety of samples from animals (individual and composite) and environmental sources (i.e. waters, sediments, beach sand). Escherichia coli and enterococci are isolated from each sample. Samples and individual isolates are archived for future study or for analysis by other researchers. Each isolate is fingerprinted by PFGE and repPCR and the digital information compared using computer assisted pattern analysis. The long-term objective of this multifaceted research strategy is to develop a fast, simple, economical yet discriminatory method for BST in MS waters. Toward this end, individual fecal samples have been obtained from humans, cows, dogs, goat, bats, chicken as well as composite environmental samples from a sewage lagoon and a coastal beach. Initial experiments to determine the best method to obtain template for PCR amplification of isolates show that it is not necessary to purify the genomic DNA before PCR. Using washed cells directly in amplification reactions yielded more distinct bands compared to using extracted DNA and boiled cells. Analyses of E. coli and enterococci isolates indicate that repand BOX-PCR yield approximately twice the number of PCR products as ERIC-PCR. Current efforts are focused on establishing a database of DNA fingerprints of known animal sources and in comparing rep-PCR and BOX-PCR to pulse field gel electrophoresis to determine the better tool for bacterial source tracking.
Environmental contaminants that affect CYP1B gene expression in channel catfish (Ictaluras punctatus)
Year: Authors: Metzger C.U., Willett K.L.
ENVIRONMENTAL CONTAMINANTS THAT AFFECT CYP1B GENE EXPRESSION IN CHANNEL CATFISH (Ictaluras punctatus)
High mutagenicity effect of cucumber
Year: Authors: Yang W.H., Yang J.R.
Various plants, vegetables, and fruits have demonstrated strong mutagenicity with or without isolation procedures. Accumulation of some specific elements or compounds by affinity binding or phytoremediation may be responsible for a part of genotoxicity. Nevertheless, the major portions of genotoxicity may have been contributed by their specific metabolic products of some specipic carbonyl compounds in their specific biological environment. Such toxic compounds may have leaked and distributed ubiquitously in the environment for the major source of mutagenecity. Both endogenous and exogenous aldehyde and ketones contributed to cancer in humans. In addition to their use in chemical industry (National Research Council, 1981), aldehyde and ketones are components of foods (Hsieh et al . 1981; Stone et al. 1975; Schreier et al. 1981; deLumen et al 1978; Reindl and Stan, 1982), intermediate in metabolism (Shauenstein et al. 1977), and end product of lipid peroxidation (Reindl and Stan 1982; Schauenstein et al., 1977; Esterbauer et al., 1982) which contribute to mutagenecity of various liquors and foods also. Methyl glyoxal is present at levels of approximately 0.5 mg per cup of freshly brewed coffee and accounts for 50% of the mutagenicity of coffee (Kasai et al. 1982). Acetol, another major component of coffee (Kasai et al. 1982) is mutagenic. Cigarettes smoke contains glyoxal, and diacetyl is present at levels of hundreds of of µg per cigarette (Morce-Testa and Saint-Jalm, 1981). Both quercetin and kaempferol are well-known flavonoids of plant and fruit which frequently cause mutagenicity in grape wines or juices (Bjeldanes and Chang 1977, Harfdigree and Epler 1978; Sugimura et al. 1977). Chlorophyll is also known to have mutagenicity effect (Sarkar et al. 1996). On the other hand, various plants, corps, vegetables, and fungi (mushroom) are also known to be antitumor or to have immune-enhanced activities against cancer(11~48). Soybean and soybean milk have demonstrated their effectiveness in inbibition of cancer growth (Barmes et al, 1990,Limtrankul et al. 1993, Yvelow et al 1985). Lentinin from Mushroom (Maeda et al 1973,Licastro et al. 1993) or lectin estract from Table of Contents the seed, champedak seeds (Hashim et al 1992) are also effective to suppress the cancer growth. Clinical trial is also currently conducted in the hospital under the approval of FDA to oral administration of the mixed soup of 20 different vegetables and fruits to control the growth of lung cancer (Sun et al. 1999). For biosafety of foods and our living environments, both toxic and mutagenicity tests of vegetables, fruits, plants and their biological products appears to be necessary and important. It is the primary object of the current study to apply the Salmonella bacterial mutagenecity test for study of genotoxicity of cucumber which has covered so large area of agriculture land and has been consumed in considerably large amount to human body through food supply chains.
Development of an index of biotic integrity for wadeable streams and rivers in Mississippi and 303(D) list evaluation
Year: Authors: Hicks M.B.
The total maximum daily load (TMDL) process requires that water resource systems (such as, streams, rivers, lakes, reservoirs, and wetlands) be evaluated for overall ecological condition, and if assessed as impaired, improved to meet their designated use(s). As of 1999, approximately 700 waterbodies in Mississippi had been listed as impaired (i.e., 303(d) listed), however, little or no quantitative data were used in establishing approximately 550 of these listings. Therefore, the Mississippi Department of Environmental Quality (MDEQ) initiated a project to re-evaluate the state=s 303(d) listed streams using biological data. These data are to be calibrated according to reference conditions and summarized in a multimetric Index of Biotic Integrity (IBI) that can be used for assessing the overall ecological condition of sites, as well as evaluating the effects of nutrient enrichment, sedimentation, habitat impairment, and land use conversions. Additionally, an IBI can aid in establishing restoration and remediation goals, tracking the effectiveness of restoration and remediation activities, and developing watershed management strategies. Approximately 130 sites were selected as candidate reference sites based on their location in natural settings according to multiple resolution land cover (MRLC) data or on personal knowledge of the stream. Over 450 stream locations (303(d) listed and reference streams) were sampled over a 6-7 week period during a winter index period spanning January B March, 2000. Data collected at all sites included field chemistry (pH, water temperature, specific conductance, TDS, turbidity, and dissolved oxygen), water grab samples for laboratory analytical chemistry (COD, TOC, TP, TKN, NH4, nitrate/nitrite, total alkalinity, and total chlorides), physical habitat (visual-based habitat quality assessment and modified 100-particle Wolman pebble count), and benthic macroinvertebrates (multiple-habitat approach). Development of an IBI involves selection of reference and stressor sites according to physical, chemical, and land use data, and subsequent determination of the biological measures (metrics) that most consistently respond to stressor conditions as indicated by abiotic data. Once metric testing and selection has been completed, the IBI is constructed, and narrative ratings that describe stream impairment status are developed. These ratings will be used for assessing the status of 303(d)-listed streams (i.e., whether listing or delisting should occur).
Genetic tools for assessing exposure to contaminants
Year: Authors: Perkins E.J., Fredrickson H.L.
ASSESSMENT OF EXPOSURE TO CONTAMINANTS. Decisions on the identification, assessment, and management of contaminated material are frequently limited by information on how much risk the material poses. A tiered assessment framework has been adopted to determine the suitability of dredged material for disposal (US Environmental Protection Agency and US Army Corps Engineers 1991). According to this framework, if there is reason to believe contamination, sediment samples should be collected, extracted, and analyzed. Chemical analyses are developed to maximize recovery of pre-targeted contaminants of interest. However, a manager must know what chemicals to look for as these tests do not detect non-targeted contaminants or those with poor detection limits. With the exception of the use of theoretical bioaccumulation estimates for nonpolar organics, chemical analyses provide no information on the fraction of the targeted contaminant available (bioavailability) to cause toxicity and subsequent risks. Managers are then required to use lengthy bioaccumulation studies to assess contaminant exposure and bioavailability. Confounding the remediation or mitigation of contaminated sediment, the causes of toxicity in sediment may never be conclusively identified using standard methods (Larson 2001). As a result, the high cost of sediment analysis constrains effective management decisions. Given the large volumes of material involved in most dredging operations, the heterogeneous distribution of contaminants in sediments, and the frequent need to make decisions during dredging operations the constraints imposed by traditional sampling regimes and analyses can result in overly conservative, and very expensive, decisions. Moreover, it may result in the unnecessary treatment of sediments where contaminants pose no risk. The lack of timely and accurate information can also result in localized hot spots escaping detection, and dispersal of toxic material into aquatic ecosystems. Direct assessment of effects precludes uncertainty due to unknown bioavailability improving the quality of information in terms of environmental risk. Sediment matrices create difficult challenges for identification of bioavailable contaminants that may cause toxicity. For a contaminant to cause any response, it must be biologically available. While bioavailability can seldom be determined solely from analytical chemistry data, responses in exposed organisms can interpreted and used to identify which chemicals are bioavailable and their potential for causing effects and toxicity due to exposure. Standard EPA tests use ecologically relevant organisms including marine benthic invertebrates, Neanthes arenaceodentata and Leptocheirus plumulosus, and freshwater benthic invertebrates, Chironomus tentans and Hyalella azteca (US Environmental Protection Agency and US Army Corps Engineers 1991
Measurement of tidal flux for the Lower Pearl River and Lake Pontchartrain estuaries of Mississippi and Louisiana using acoustic doppler velocity tech
Year: Authors: Turnipseed D.P.
During 2000-2001, the U.S. Geological Survey (USGS), in cooperation with the Ocean Modeling and Prediction Division of the U.S. Naval Oceanographic Office (NAVOCEANO), constructed tidal gages at the East Pearl River at CSX Railroad near Claiborne, Mississippi, at the Rigolets at CSX Railroad near Rigolets, Louisiana, and at the Chef Menteur Pass at CSX Railroad at Chef Menteur, Louisiana, to collect data that could be used to assist in computing the tidal flux of the Pearl River and Lake Pontchartrain estuarine systems in Mississippi and Louisiana. Each gage records continuous tidal stage, velocity, water temperature, specific conductance, and salinity, and transmits these data via satellite for output to the USGS real-time Internet portal at: http://water.usgs.gov/ms/nwis/rt This effort provides tidal flow data that assist NAVOCEANO with the calibration and maintenance of the RMA2 flow model for the Pearl River and Lake Pontchartrain estuaries in the northern Gulf of Mexico region in Mississippi and Louisiana. On September 13-14, 2001, during about a 25-hour low-flow tidal cycle personnel of the U.S. Geological Survey measured discharge at three CSX Railroad crossings. These railroad crossings represent the major inlet/outlet conduits for Lake Pontchartrain, Louisiana. Data were also collected to develop stage/area relations and to correlate several water-quality properties measured during the study with those being recorded at the gages. These data provide input to compute near-real time tidal discharge influencing Lake Pontchartrain and the Lower Pearl River estuaries. Due to the existence of numerous small outlets for flow in and out of the Pearl River and Lake Pontchartrain estuaries, the surface-water and water-quality data presented in this paper represent only conditions in and out of the three gaged bridges and are not representative of the entire tidal flux of these estuaries. Data presented in this paper are provisional and subject to revision upon further review by the USGS.
Increasing communications among watershed stakeholders
Year: Authors: Oldham L.
Watershed Forum Roundtables assemble disparate stakeholders for dialogue, networking, and education to enhance local watershed initiatives and to communicate watershed news, programs, and resources. The goals are facilitated cooperation between the public and private sectors, and improved advocacy of water quality and quantity issues in government agencies. A group of private and public sector entities convened the first Mississippi Watershed Forum Roundtable in September, 2001. Education was provided on watershed topics, and various watershed protection success stories from around the state were presented. An issues panel from industry, local government, environmental organizations, agriculture, and state regulatory agencies discussed water quality and quantity issues from their perspectives. Breakout sessions considered various protection efforts working, or not working at the local level, needed improvements to current efforts, and future directions for the state. The participants stressed more interagency coordination and cooperation, increased funding for initiatives, increased local government and industrial awareness, and increased education on watershed issues. Most participants appreciated the opportunity to network with other stakeholders. Over two thirds of the participants felt the training workshops and breakout discussions were beneficial. Ninety-six percent of the evaluations suggested the Roundtable be repeated either annually or biannually. Regional Roundtables are being developed, and the next statewide Roundtable is planned for February, 2003.
Considerations for water resource bioassessments based on aquatic macroinvertebrate communities: Mississippi experiences
Year: Authors: Testa, III S., Cooper C.M.
Bioassessment and Mississippi Assessment of biological communities to evaluate water quality has received muchincreased attention over the past half decade. Following the passage of the Clean Water Act in 1972, and its amendments in 1987, legislation has tightened the association between aquatic biological communities and water quality regulation in the United States. While some states developed strong bioassessment and water regulatory programs, this was the exception rather than the rule, and by year 2001, 39 states were involved in litigation related to determination of impaired waterbodies or rehabilitation plans for those thought to be impaired ( http://www.epa.gov/owow/tmdl ). Mississippi’s inclusion in the 1998 consent decree with EPA (U.S. Environmental Protection Agency) concerning the state’s impaired waterbody list brought the issues of water regulation and bioassessment to the forefront of concern to Mississippi state legislators, regulatory agencies and numerous other stakeholders involved with Mississippi water resources. Bioassessment has become necessary to discern condition of Mississippi’s waters, including identification, monitoring and TMDL supportive information associated with the 303(d) list of impaired waterbodies. It also relates to other Clean Water Act activities, including water quality assessment [305(b)] reporting, section 314 and 319 assessments, section 402 monitoring, ecological risk assessments, and section 303(c) water quality criteria and standards. Mississippi currently has time deadlines for development of new nutrient criteria for incorporation into State water quality standards to prevent promulgation of national nutrient criteria upon the state by EPA, and use of bioassessment information has been selected to play a critical part in the State’s efforts to determine its own locally appropriate nutrient criteria. Specific assessment methods must be valid; e.g., they must provide what is needed; that is, in the case of Clean Water Act requirements, a measure of the ecological condition of a waterbody to assess its "biological integrity". Biological communities suggested by EPA for use in bioassessment programs by states include macroinvertebrates, fish, and periphyton. Nationally, macroinvertebrates dominate as the community selected by states for their bioassessment programs. While there have been many advances in our knowledge of aquatic invertebrate communities in the past few decades, many questions still remain concerning proper methods for evaluating overall community condition. Questions include: when to sample; where to sample; how to sample; what are proper methods for analysis, interpretation and reporting; what are the effects of stream size, regional conditions, sampling using artificial substrates, sampling difficult natural substrates, sub-sampling field collected material, fixed-count sub-sampling of macroinvertebrate individuals, large-rare organism sorting, level of taxonomic identification, and taxonomic instability. These concerns escalate when researchers or agencies attempt to make comparisons over wide spatial regions (i.e. state-wide) subject to large variations in stream characteristics and conditions, and comparisons may need to be made over long periods of time (years or even decades). What are the proper methods that will give us the ability to make the right decisions? Limited amounts of resources are available to complete these large-scale bioassessment programs. We wish to not only be scientifically sound but to avoid the waste of monies and effort on failed or flawed methods. Rapid Bioassessment EPA recognized that simplification and greater ease were needed to allow bioassessment programs to meet required large-scale studies, Table of Contents especially where states would need to survey hundreds, and in some cases, thousands, of stream sites. In 1998, the Mississippi Department of Environmental Quality (MDEQ) stated that actual monitoring data had only been made for one third of one percent of total stream/river miles in Mississippi (about 280 of 84,000 miles) (MDEQ-OPC, 1999). The 1998 303(d) list for Mississippi included over 700 waterbodies that were in immediate need of assessment. EPA first published rapid bioassessment protocols in 1989 (Plafkin et al.), but the suggested method had been developed primarily from research in high gradient cobble bottom streams. This 1989 protocol was also based primarily on sampling from a single habitat, the riffle, supplemented with coarse particulate organic matter (CPOM) sample. Researchers and management agencies in geographic areas that lacked high gradient cobble bottom streams and others that felt emphasis on a single habitat was insufficient to characterize the condition of a stream reach, often continued to use methods that included sampling from several
The phytoremediation of creosote contaminated soil
Year: Authors: Allen C.E., Borazjani H., Diehl S.
Creosote is a common organic wood preservatives used in the wood treating industry for over 100 years. Soil contaminated with creosote has been found in many former and active wood treating plants. Soil contamination at these sites has resulted from past practices and accidental spillage. Physically removing these contaminated soils is not a cost effective method of cleanup. An option in certain situations is to use a form of bioremediation called phytoremediation as a means of degrading these pollutants. Phytoremediation is the use of plants to enhance degradation or sequester harmful contaminates found in soil and water. Phytoremediation is gaining popularity for its low cost insitu treatment of contaminates. Compared to other remediation technologies, phytoremediation appears to produce results comparable to landfarming and offers protection against erosion, maintains proper soil conditions, and is less laborious than landfarming (Andreotti, et al 2001). Phytoremediation provides four avenues of approach for contaminated areas: 1.) microbial degradation of contaminates within the rhizosphere. 2.) hyperaccumulators where plants uptake and store harmful contaminates, commonly heavy metals, in their roots and shoots. These plants are later harvested and disposed of in a proper manner. 3.) rhizofiltration where plant roots absorb, concentrate or, precipitate heavy metal ions from water. 4.) phytovolitization where plants uptake volatile organic compounds (VOCs) in groundwater allowing them to be released into the atmosphere via the stomata openings. Surface waters and shallow aquifers were Table of Contents 2 the first sites where plants were applied as a method of cleanup (Cunningham, 1997; Carman, 1997; Ensley, 2000). Many different plants and trees have been used in the removal or degradation of toxic pollutants. Trees like poplar, willows, and cottonwoods removed contaminants from ground water (Glass, 1998). The biggest disadvantage in using trees for environmental cleanup is the time needed for tree growth. Faster growing flora like grasses may be more suited for some situations. Although the roots of grasses do not penetrate the soil at depths associated with tree roots, they can proliferate within the topsoil. Most herbaceous plants only produce roots within the first three feet of soil. Alfalfa, in contrast, can produce roots that will extend to a depth of six feet (Stern, 1991). Without healthy growing plants, phytoremediation would not be successful, thus the ideal environmental conditions for the plants should be provided. For alfalfa, an N-P-K ratio of 0-24-24, respectively, is generally recommended. Boron is often added in trace amounts to promote growth (Kimbrough, 1999). Ryegrass is generally fertilized with (N-P-K), 13-13-13 and a soil pH of 6.5 is needed. Often, ryegrass and alfalfa rotated on a site will make ideal counterparts. The soil pH needed to grow alfalfa is analogous with the soil pH of ryegrass. Ryegrass requires high levels of nitrogen for growth, where as for alfalfa no nitrogen needs to be added because rhizomes fix nitrogen in the soil. Rotating both species will reduce the fertilizer requirements for each growing season (Kimbrough, 1999a). 3 The objectives of this study were to evaluate the effectiveness of ryegrass for the remediation of creosote during the winter months, and to evaluate the effectiveness of alfalfa for the remediation of creosote during the summer months.
A predictive model for land-use planning at the watershed-scale based on fish community composition
Year: Authors: Schweizer P.E., Matlack G.R.
Land use practices may influence the biotic integrity of nearby freshwater streams. Soil surface conditions caused by land use influence the rate and character of runoff received by the stream, influencing soil erosion, sediment transport, and downstream sediment deposition. Impacts in stream systems may be quite dramatic, especially in headwater and low- order streams such as coastal plain creeks. Although it is obvious that stream bank disturbance affects adjacent streams, it is unclear how watersheds integrate land uses throughout the drainage area. The Mississippi coastal region has experienced a rapid increase in population during the last two decades. Economic development is certainly welcome, but its impacts on natural resources such as water quality, and native biological diversity are poorly understood. Casual observation suggests there has been a severe impact on streams in recently developed areas. Because tourism is one of the state’s fastest growing industries, and economic expansion is likely to continue, developing ecologically sound development practices is of the highest importance. We will evaluate different models of watershed function by a detailed comparison of land use and stream quality. Results will be used to develop a predictive model for use in environmental management and planning in the south-Mississippi region. Multispectral aerial photography is essential to this project because it can provide a precise description of land use distribution over large areas. Land use data will be integrated with stream and topographic data layers in a GIS environment at a variety of spatial scales. Background Unlike stream pollution from industrial and sewage treatment plants, land use contributes pollution in a diffuse, unlocalized form described as Nonpoint Source pollution (NPS). NPS pollution is caused by rainfall over large areas moving over and through the ground to stream channels. Runoff picks up natural and humangenerated pollutants as it goes, depositing them into lakes, rivers, Wetlands, coastal waters, and even underground sources of drinking water (EPA, 1997). These pollutants include excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas, oil, grease, and toxic chemicals from urban runoff and energy production, sediment from improperly managed construction sites, crop and forest lands and eroding stream banks, bacteria and nutrients from livestock, pet wastes, and faulty septic systems (EPA, 1997). Although difficult to quantify, NPS may degrade aquatic ecology with loss of fish, shellfish and wildlife habitat, and reduce the aesthetic quality of the aquatic environment (Jensen, 2000). Degradation of stream health is commonplace wherever human settlement occupies large areas of a watershed (Allan, 1995). Degradation can be linked to physical changes associated with development which typically alters the rate and volume of runoff (Wahl, et al., 1997). Impervious surfaces such as pavement or roofing reduce water retention and amplify runoff in storm events (Jurmu and Andrle, 1997). Runoff is further accelerated through engineered drainage systems (Corbett et al., 1997). In some cases storm flow may significantly alter channel morphology in a single event. Urbanization often results in decreasing width of natural stream corridors and loss in riparian vegetation which could potentially absorb runoff (Forman, 1995). High surface runoff reduces the opportunity for pollutant filtering by subsurface flow. Urbanization typically increases stream transport of sediments and nutrients, with increased runoff of lawn fertilizers, sewage and roadside dust, and, by bank scouring, contributes to the loss of forested cover in riparian buffer (Wahl et al., 1997). Little information is available on watershed-scale consequences of land use, but observations of Table of Contents developing watersheds suggest integration of land uses over large areas. When naturally vegetated landscapes are converted to urban or agricultural uses, streams often appear to be affected, usually showing habitat degradation and negative impacts on stream biota (Roth, et al., 1996). In the Hattiesburg area, preliminary work indicates that both local and watershedscale factors contribute to geomorphology and biotic conditions in local streams (Schweizer 2000). Changes in land use appear to be causing flooding of homes and commercial properties (Maute, 2000, Crager, 2001). Channel erosion due to urbanization can become the predominant source of excess sediment to downstream reaches and result in degradation of biotic integrity (Bledsoe and Watson, 2001). Wang et al. (1997) analyzed relationships between watershed land use and biotic integrity of streams in Wisconsin and found that stream habitat quality were positively correlated to the amount of forested land in the draina
Validation and predictions of the Annagnps runoff model for portions of the Upper Pearl River Watershed
Year: Authors: Tagert M.L., Shaw D.R., Massey J.H., O'Hara C.G., Bingner R.L.
Landsat images were combined with other digital data such as digital elevation models (DEMs) and soil classification information to be used as inputs in the United States Department of Agriculture’s (USDA) Annualized Agricultural Non-Point Source (ANNAGNPS) pollution model. ANNAGNPS is used to predict non-point source pollutant loadings in agricultural watersheds. DEMs with a 1:24,000 resolution were obtained from the United States Geological Survey’s (USGS) National Elevation Database (NED), and digital soil data is from the USDA Natural Resources Conservation Service (NRCS) State Soil Geographic Database (STATSGO), at a scale of 1:250,000. All digital data were re-projected from their original form into a modified Universal Transverse Mercator (UTM) projection. The TopAGNPS module of AGNPS, using the DEM as the main input, performed a topographic evaluation of the watershed as well as drainage area identification, synthetic channel networks, watershed segmentation, and subcatchment parameters. Sediment sampling began in October, 2001, and will continue for at least one year in the Upper Pearl River watershed. Water sampling is being performed at the following sites: Burnside, Edinburg, and Carthage. Sediment samples were analyzed via the filtration method. USGS field sampling methods and laboratory procedures were used as a guide for the retrieval and analysis of sediment samples. Large storm events were sampled in October and January, resulting in higher average sediment concentrations than November for all three sampling sites. Average monthly sediment concentrations for October were 28 mg/L at Burnside as well as at Edinburg, while Carthage had an average concentration of 49 mg/L. November yielded average concentrations of 9, 12, and 6 mg/L at Burnside, Edinburg, and Carthage, respectively. Average sediment concentrations for January were 19, 19, and 48 mg/L at Burnside, Edinburg, and Carthage, respectively. The sediment concentrations obtained from the samples will be compared to the predictions of the ANNAGNPS model for validation purposes. Pesticide sampling will also be performed during the spring and summer of 2002 and compared to the pesticide loading results of the model. In addition, future research involves determining the effects of land use changes by comparing the model predictions with the current land usage to the model results using late-1980’s land usage.
Effects of tillage and residue management on runoff and erosion
Year: Authors: Wilson G.V., McGregor K.C., Dabney S.M.
Numerous studies have shown the benefits of notill (NT) cropping systems at reducing erosion. Quantitative information is needed on how residue contributes to erosion control and the impacts of converting NT systems back into conventional-till (CT) systems and vice versa. The objective of this study was to use long-term CT and NT plots to elucidate the effects of residue and tillage on runoff and erosion. Rainfall simulations were conducted on 13 plots in year 1 and 11 plots in year two. Plots had an average slope of 5.6% on a Grenada silt loam (Glossic Fragiudalf) soil. Rainfall was applied to a 3.7 m by 10.7 m area within plots at a rate of 65 mm/h for one hour under natural antecedent soil-water conditions (dry run), followed by a 0.5 h simulation four hours later (wet run), and another 0.5 h application 30 minutes later (very wet run). Runoff and soil loss were adjusted for variations in rainfall to the prescribed application rate and soil loss was further adjusted for difference in slope among plots. NT systems exhibited greater runoff than CT systems, however, sediment losses were greater for CT. Initial response to residue removal was an increase in runoff and erosion for both systems. The second year of residue removal did not affect runoff but caused substantially higher sediment losses particularly for plots with a history of NT. The lack of carryover in beneficial NT propoerties resulted in NT systems having similar erosion rates as CT systems by the subsequent year of residue removal. This work demonstrates that residue management can be more important than the tillage system for erosion control.
Summary of the Hurricane Mitch Relief Program of the U.S. Geological Survey
Year: Authors: Baldwin W.T.
In October 1998, Hurricane Mitch slammed into Central America with sustained winds of 180 miles per hour. The countries of Honduras, Nicaragua, El Salvador, and Guatemala were hardest hit. Hurricane Mitch was a Category 5 storm on the Saffir-Simpson scale and ranks as one of the strongest storms on record based on its sustained winds, barometric pressure, and duration (National Climate Data Center, 1999). The measured rainfall resulting from the storm totaled as much as 6 feet in some areas (National Climate Data Center, 1999). The resulting flooding and landslides killed more than 9,000 people and left thousands more missing (Smith, Phillips, and Spahr 2002). In Honduras, an estimated 75 percent of the transportation infrastructure was rendered useless, and 50 years of economic development was destroyed (Smith, Phillips, and Spahr 2002). Economic losses in the region were estimated at more than 7.5 billion dollars (U.S. Agency for International Development, 1999).
The geology of ground water in Mississippi: A commentary
Year: Authors: Dockery, III D.T.
In a discussion of economic geology many years ago, I was asked by a professor, "What is any region’s most valuable natural resource?" My thoughts immediately turned to pricey resources such as gold, silver, diamonds, and other precious stones, but the correct answer was "water," in particular good drinking water. This resource supplies our next most critical need after we have air to breathe. There are large unpopulated tracts of earth that are desolate because of a lack of water. Even in the humid sub-tropical climate of Mississippi, the Mississippi Department of Environmental Quality has identified "water quantity" as the most pressing issue it will face in the coming years.
A contrast in water resource development and settlement patterns: Black Prairie and North Central Hills regions of Mississippi
Year: Authors: Schmitz D.W., Wax C.L.
The type of water source available to support life is strongly connected to human’s use of the landscape. Settlement patterns and densities are related to the accessibility of a stable and potable water resource to support domestic use. As technologies for providing more stable and higher quality water sources have emerged through time, populations and settlement distributions have grown and changed. Earliest settlements used primarily surface water, with wells generally not becoming commonplace until the late 1800s. The use of groundwater, with the exception of spring water, was unusual throughout most of the nineteenth century until pollution and disease in surface waters forced people to develop groundwater (Kazmann, 1972). An investigation into water resources of the Black Prairie (Prairie) and North Central Hills (Hills) regions of Mississippi showed that the geology of the Prairie region exerts a stronger control on the presence of sources of water for human use than in the nearby Hills region, which is not underlain by chalk. Figure 1 shows the relationship between the controlling geology and surface water features of the Prairie region. It can be seen that perennial streams do not exist unless their source is outside the Prairie. The control of the chalk on the course of the Tombigbee River on the eastern edge of the Prairie is also evident. In contrast, Figure 2 shows the ubiquitous water features in the sandy terrain of the Hills region. The development of water resources in both the regions appears to fall into several discrete time categories, each associated with identifiable technological innovations. Each of the categories of technology provided certain constraints or opportunities for settlement in the regions. Each progressively higher level of technology allowed greater opportunity for a less limiting arrangement of house sites and settlement distribution. The purpose of this study is to document the different levels of water resource technology that were used to support humans as they occupied these two regions from prehistoric times to the present.
Stage-discharge ratings for nine streamgages in El Salvador and Guatemala
Year: Authors: Winters K.E.
In 1998, streamgage networks in Central America suffered heavy damage as a result of Hurricane Mitch. The networks required much repair to be operative for use in river forecast systems and in planning for disaster preparedness and mitigation. To address this need, the U.S. Geological Survey (USGS) installed or retrofitted nearly 40 streamflow gaging stations in the countries of El Salvador, Guatemala, Honduras, and Nicaragua. An integral part of each gaging station is the stage-discharge rating curve, which is critical for the successful implementation of river forecast systems. In 2001, the USGS developed stage-discharge ratings for nine selected streamgages in El Salvador and Guatemala. This work was done as part of the Hurricane Mitch Program of theUSGSin cooperation with the U.S.Agency for International Development (USAID). Hurricane Mitch became a Category 5 (Saffir-Simpson scale) storm in the southern Caribbean Sea on October 26, 1998, with sustained winds of 180 mph. The hurricane stalled off the coast of Honduras before moving inland. Because of this, much of the ground along the storm’s path was already saturated before the most intensive rain fell. The flooding and landslides caused by Hurricane Mitch resulted in 9,000 deaths in Honduras, Nicaragua, Guatemala, and El Salvador. This disaster punctuated the need for real-time streamflow monitoring in the region. From 1999 to 2001, existing streamgage networks in Central America were augmented by the USGS to establish a real-time river forecast system. Existing gages were repaired, nearly 40 new streamflow and rainfall gages were established, and satellite telemetry was installed at each gage. The network includes nine streamgages in El Salvador and four in Guatemala. Stage-discharge ratings were developed in 2001 by the USGS for nine streamgages in Central America, including six in El Salvador and three in Guatemala (fig.1). Ratings were developed for gages located on the Rio Lempa (sites 1-3), Rio Sumpul (site 4), and Rio Grande de San Miguel (sites 5-6) in El Salvador, and the Rio Ostua (sites 7-8) and Rio Coyolate (site 9) in Guatemala.
Mississippi DEQ approach to fecal coliform TMDLS
Year: Authors: Carroll-Perkins A.Z.
The development of total maximum daily loads (TMDLs) is required for waterbodies not meeting their designated use by Section 303(d) of the Clean Water Act and the implementing federal regulations at 40 C.F.R.§130.7. A TMDL is the total maximum daily load of a pollutant that a waterbody can receive and still meet it’s designated use. Mississippi Department of Environmental Quality (MDEQ) has completed 96 Fecal Coliform TMDLs since 1999. These TMDLs have been prepared in accordance with the schedule contained within the federal consent decree between EPA Region Four and the Sierra Club dated December 22, 1998. These TMDLs were done on waterbodies on the Mississippi 1998 Section 303(d) List of Waterbodies. During the past few years, the MDEQ approach to Fecal Coliform TMDLs has undergone many changes and has been finetuned in many ways. The components that have been affected include source assessment, water quality monitoring, modeling approaches, and both hydraulic calibration and water quality calibration.
Developing a total maximum daily load (TMDL) for fecal coliform bacteria in a Mississippi coastal estuary
Year: Authors: Caviness K.S.
The identification of waterbodies not meeting their designated use and the development of total maximum daily loads (TMDLs) for those waterbodies are required by Section 303(d) of the Clean Water Act and the Environmental Protection Agency’s (EPA) Water Quality Planning and Management Regulations. The TMDL process is designed to restore and maintain the quality of those waterbodies through the establishment of pollutant specific allowable loads. The Mississippi Department of Environmental Quality (MDEQ) has identified several segments within the Biloxi Bay Watershed as being impaired by fecal coliform bacteria as reported in the Mississippi 1998 Section 303(d) List of Waterbodies (Figure 1, Table 1). The listing of these waterbody segments was influenced by both water quality monitoring data and shellfish classifications. The TMDLs for these waterbody segments were developed through a monitoring and modeling project. The development of a water quality model for this project was conducted under contract by the Civil Engineering Department at Mississippi State University (Huddleston, et. al., 2001).
Water Quality Impacts of Best Management Practices under Environmental and Equity Constraints in the Mississippi Watershed
Year: Authors: Intarapapong W., Hite D., Isik M.
Modern agricultural systems depend on the use of natural resources and a wide range of industrial inputs such as fertilizers and pesticides. Agricultural cultivation, combined with use of chemical inputs, can impose significant damages to environmental quality in the form of soil erosion, waterways sedimentation, and chemical runoff. To lessen the environmental problems associated with agricultural production, a number of programs have been introduced to directly limit environmental degradation, including the Conservation Reserve Program (CRP) that offers annual rental payments and cost-share assistance to farmers in an exchange for setting aside some portion of land (USDA, 1998). Recently, Total Maximum Daily Load environmental standards (TMDL) have come under consideration to reduce environmental runoff of nutrients, chemicals and sediment. Best management practices including crop rotations and alternative tillage practices (no-till and conservation tillage) may help farmers comply with TMDL rules. Levels of BMPs adoption will ultimately depend on the impact of such conservation practices on farm profitability. A number of studies have been conducted to investigate runoff reduction and profitability associated with alternative practices, using either experimental plot data or simulation models. To analyze profitability of different fixed rotation and input combinations, Funk et al. (1999) used 8 input combinations of commercial fertilizer, insecticides, and herbicides on a research plot utilizing corn, soybean, and a corn/soybean crop rotation in the Brazos River Bottom Research Farm of Texas. They found that input combinations that do not fully utilize levels of fertilizer, pesticides and herbicides (e.g., fertilizer-insecticide-no herbicide, fertilizerno insecticide-herbicide, fertilizer-no insecticideno herbicide) consistently ranked among the highest of expected net returns and were the preferred input strategy for corn-soybean rotation systems. In a similar fashion, Helmers et al. (1986) used experimental test plots on thirteen cropping systems in East Central Nebraska, and found that row crop rotations had higher returns than continuously grown crops, and a corn-soybean rotation system was more stable, in terms of net returns, than continuous corn or soybeans. Using experimental data on 3 pest management systems and 2 tillage practices for 3 cropping systems, Zavaleta et al. (1984) found that corn/soybean rotations had higher yields and higher net returns than either continuous corn or soybeans. In addition to crop rotations, no-till practices have been shown to reduce soil erosion, while causing no significant reduction in crop yields. (Phillips et al. 1993). To reduce environmental damages resulting from traditional agricultural cultivation, conservation practice, including minimum and no-till operations, have been adopted by some farmers. No-till operations have the potential to reduce erosion by up to 90% and conserve 2-4" of soil moisture for dryer periods (USDA). Despite the benefits of conservation tillage practices, they have not been widely adopted by farmers. It is hypothesized that adjustment costs associated with equipment replacement and risk aversion regarding yield uncertainty under this technology could play significant roles in low adoption rates. Krause and Black (1995) examined the factors affecting no-tillage technology adoption of representative farmers in Michigan, and found that risk averse farmers would wait until their current conventional planters had aged many years before adopting no-tillage technology, mean yields constant across the two technologies. For profit- Table of Contents maximizing representative farmers, adoption is quicker if it is assumed that there is no learning curve. Ultimately, acceptance and optimal implementation by farmers will depend on the effect of conservation tillage on farm profits. In addition to minimizing loss in net return due to an implementation of environmental restrictions, the equity impact of such policies should be considered. Changes in net return bought on by environmental restriction may vary from farm to farm, depending on soil characteristics, topography, etc. To investigate watershed level impacts of such policies, in our optimization model, the equity constraint of equal per acre profit for each farm will be simultaneously imposed with environmental restrictions. To evaluate the full scope of economic and environmental impacts of BMPs, analysis at both farm and watershed levels must be addressed. At the farm level, BMPs will allow farmers to reduce soil, nutrient and chemical losses, which may provide benefits to farmers in the terms of improved soil productivity. However, farmers may perceive that conservation practices would also result in reduced crop yields and/or increased costs. Thus, benefits from avoided environm
Responses of individual wetland plant species to shading by the dominant, early-successional rush, Juncus Effusus L.
Year: Authors: Ervin G.N.
Juncus effusus (soft rush, Juncaceae) is a perennial species of freshwater wetland plant capable of year-round photosynthesis and growth at temperate latitudes. This species has been shown to produce dense canopies that significantly depress species diversity of the surrounding plant assemblage during early secondary succession in newly exposed wetland areas. Experimental reduction of shading by J. effusus in a recently-drained beaver impoundment revealed a strong regulatory influence of this dominant freshwater emergent plant on species richness and composition of the surrounding plant community. Analyses of biomass, species composition, and light reduction by J. effusus indicated that growth of certain species varied with shading intensity. Examination of responses on a species -byspecies basis indicated the potential for shifts in community composition toward a plant assemblage of primarily perennial species and those well-adapted to wetland conditions (obligate to facultative wetland indicator status). Perennial grasses and sedges appeared best able to tolerate or avoid shading, while the nonrhizomatous annual sedge, Eleocharis obtusa, and non-rhizomatous dicot species such as Rhexia virginica and Xyris spp. exhibited depressed biomass accumulation when exposed to J. effusus shading.
Establishment of groundwater protection policy for the University of Mississippi field state - Lafayette County, Mississippi
Year: Authors: Swann C.T., Lutken C.B., Holland M.M.
The University of Mississippi Field Station [UMFS] is a relatively new component of the research capabilities of The University of Mississippi, located approxim ately 11 miles from the main campus, in rural Lafayette County. Numerous springs and seeps, resulting from aquifer leakage, make the Field Station a natural laboratory for the study of wetlands, and interactions between groundwater, surface water, and the biota. Initial development of research laboratories and culturing facilities has recently been completed and m ore is planned. At this early stage of facility expansion, groundwater protection has been established to protect this source of water supply and vital component of wetlands research. The Field Station is situated on the eastern extreme of the Meridian Sand outcrop belt and utilizes the Meridian - upper Wilcox aquifer. The Meridian Sand is an easily mapped, lithologic unit, regionally, but on a local scale may be complex. Clay lenses and fine-grained sand facies produce unusual groundwater conditions. Within the boundaries of the Field Station, for example, the aquifer is under water table conditions in upland areas while flowing artesian conditions prevail in the flood plains. Groundwater protection policy must accommodate these varying conditions and the attendant differences in contamination potential. Of primary concern are the upland areas where the aquifer is unconfined and potential surface to subsurface contamination is greatest. A circular 500 foot well-head protection zone has been established, centered on the supply wells. Particular care is exercised in this area in the use and tracking of potential contaminants. An existing well inventory has been initiated and policy established for new well construction, well use, and final fate (continuing use or plugging). Groundwater protection will continue to be a concern as existing facilities are relocated or new ones built. The flood plain areas contain numerous experimental ponds, so potential for contamination there is closely monitored. The flowing artesian conditions minimize the potential for groundwater contamination, but present a potential for surfacewater contamination. Construction and wells in the flood plains are discouraged and additives to experimental ponds are to be carefully screened and tracked. Careful peer review by the Field Station User Committee continues to focus research and educational projects on appropriate and sustainable water uses (UMFS User Guidelines, 2002).
Waste management alternatives to reduce non-point pollution
Year: Authors: Renck A.W., Hite D., Intarapapong P., Oldham L.
The poultry industry is an important enterprise in Mississippi. The industry contributes 32 percent of the total farm value of all agricultural products produced in the state. The majority of this income is provided by broiler production. More than 700 million broilers are produced in the state annually with a farm value of $1,370 million. The production method of broilers has changed over the last several years. The industry is now commonly referred to as vertically integrated. This means an individual company performs or controls all or most production aspects. A contract system between growers and poultry companies is used to control the stages of production. Resources are utilized with maximum efficiency to produce uniform birds. Broilers are typically grown in enclosed houses that provide maximum control over the birds’ environment. A typical broiler house will produce 125 to 150 tons of litter material annually. Before building a poultry house, a producer must have a plan for poultry litter disposal. The normal practice is to apply the litter to pastureland as fertilizer. However, in areas of concentrated poultry production, overfertilization of land can occur. This may contribute to excess nutrient run off into the surface and ground water supplies. One solution to overfertilization is to transport the litter from areas of concentrated broiler production in the state to areas with cropland that can use the litter as fertilizer. A study in Alabama found that using broiler litter as fertilizer. not exceeding 4 tons per acre is as environmentally safe as using any routine commercial fertilizer application. When poultry manure is applied to match the nutrient needs of crops, the economic value of nutrients in poultry litter can be maximized. First, the areas of concentrated production had to be identified. The top five counties in broiler production are Scott, Smith, Leake, Simpson, and Jones. The amount of broiler litter produced annually in each of these counties was calculated. The next step was to identify the counties that could use the litter as fertilizer. The amount of litter each county could use annually was based on the acreage of corn, sorghum, wheat, rice, cotton, and pastureland in the county. The proper application rate of poultry litter differs for each crop and was considered in calculating how much fertilizer each county could use. Proper utilization of litter as a fertilizer is generally based on nitrogen rates. This was the method also used in this analysis to determine application rates. In the future, it is possible that phosphorous rates will also have to be considered in determining application rates. This could double or triple the land requirements for proper utilization. It is unrealistic to assume that each county will completely convert from commercial fertilizer use to using broiler litter; therefore, different adoption rates were assigned to each county and the acreage of cropland adjusted accordingly. In assigning adoption rates to each county, the farm structure of each county was considered. Counties composed of mostly large farms (over 500 acres) were given a 25% adoption rate. Counties consisting of mostly middle size farms (150 acres or more) were given a 15% adoption rate. Finally, those counties with mostly small farms (less than 150 acres) were given a 5% adoption rate. The adoption rates were assigned this way due to the infeasibility of small farms adopting this practice due to increased costs, convenience, and other practical reasons.
Streamside management zones: Are they effectively maintaining water quality in the sand-clay hills of Northeast Mississippi
Year: Authors: Young B.W., Schoenholtz S.H., Dibble E.D., Ezell A.W.
Best Management Practices (BMPs) have been established in many states to prevent or minimize impacts from non-point sources of pollution. One of the most widely used tools in a BMP strategy is the Streamside Management Zone (SMZ): an area of pre-existing vegetation adjacent to stream channels that is designed to maintain water quality by filtering andlor transforming pollutants from surrounding areas before they reach the stream. Although SMZs have been widely used by forest industry. the majority of research on the subject has focused on agricultural applications. The objective of this ongoing research is to evaluate the effectiveness of SMZs in reducing non-point source water quality degradation as it relates to timber harvesting. Nine, first- or second-order, perennial streams located in the Sand-Clay Hills Subsection of Mississippi were divided into three treatment groups: (1) unrestricted harvest with no SMZ (2) harvest with SMZ and (3) unharvested reference. Streamwater is being sampled daily using automated water samplers and biweekly using grab samples. Samples are collected at an upstream and downstream point and are monitored for total suspended sediment, turbidity, temperature, pH, electrical conductivity, dissolved oxygen, nitrate, orthophosphate. sulfate, ammonium, calcium, magnesium, and potassium. Erosion and deposition within 30 meters of stream banks are being monitored through the use of erosion-stake transects. Initial results suggest a high degree of variability among streams. However, initial responses show within-stream variability has increased for total suspended sediment, turbidity, and temperature in streams that did not have SMZ buffers from timber harvesting. This suggests that forestry SMZs in the Sand-Clay Hills Subsection may be effectively maintaining water quality.
Dechlorination of PCBs and CAHs using Na/NH3: Application to soil remediation
Year: Authors: Pittman, Jr. C.U., He J.
PCBs and other chlorinated aromatic compounds are distributed in soils and sludges at over 400 sites in the USA. CAHs occur as serious contaminants at 358 major hazardous waste sites in the USA and they migrate vertically through soils to form DNAPLs on aquifer bottoms. Nitro compound wastes abound around amunition plants and nitration operations. Every state is represented in this problem. One example is DOES Hanford site which has a groundwater carbon tetrachloride plume extending over 70 sq. miles. Many contaminated sites exist in the Gulf Coast region (Texas through Florida) where the largest concentration of chemical manufacturing plants in North America is located together with many DOD sites. Thus a national need exists for both ex-situ and in-sifu methods to destroy these pollutants in soils and sludges rapidly at ambient temperature before they migrate into groundwater. We have demonstrated that both NalNH, and CalNH, solutions (solvated electrons) will dechlorinate PCBs and CAHs in seconds at ambient temperature even in the presence of excess water. PCB- and CAH-contaminated soils (as received clay, loam and sandy soils containing up to 25% water) were successfully decontaminated within 30 sec. at 25°C. PCB and CAH destruction efficiencies >99.9% were achieved. NalNH, was more efficient than CalNH,. This advantage of Na vs. Ca increases as the H20/RCI increased. Rates of dechlorination of CCI.,. CH3CC13 and some chloroaromatics were found to occur at diffusion controlled rates as demonstrated by reductions in Na-deficient environments. Intermediate dechlorinated products (such as CHCI, or CH2C12 were not observed in CCI4 reductions. Only CH4 and CCI4 were detected. Chlorinated phenols (pentachlorophenol, 2,4,6-trichlorophenol and 2-chloro-4-fluorophenol) are all completely dechloronated at room temperature. We have now successfully defluorinated alphatic and aromatic fluorine compounds. Flourinated alkanes, upon treatment with TiCI4, undergo immediate exothermic halide exchange producing insoluble TiF3CI and chlorinated hydrocarbons. These chlorinated species are then quantitatively dechlorinated in NalNH, at diffusion controlled rates. This is the first practical method ever developed for rapid remediation of hazardous fluorinated aromatics. Note that TiCI4 is a cheap commodity chemical which produces inert Ti02 in the environment. Finally, nitroaromatic compounds have been successfully destroyed in model compound studies. Soil trials are planned in the near future. The major goal is to develop solvated electron chemistry (e. g. NalNH,) as a single, multifunctional, portable technology applicable to both on site in-situ and on site ex-situ destruction of PCBs, CAHs, pesticides, herbicides, chemical warfare agents and munitionlexplosive residues. Even if only half of these classes of pollutants can be rapidly destroyed in solvated electron media, this single technology would have broad application.
Critical Water Issues in Mississippi
Year: Authors: Ballweber J.
A.Regional Issues: Mississippi is impacted and critical to resolving numerous regional water quality issues 1. Cooperate/Coordinate to develop water quality criteria and TMDLs for interstate waters 2. Assorted issues pertaining to the Lower Mississippi River Basin and hypoxia in the Gulf of Mexico (nutrient management) B. Mississippi’s Critical Issues 1. Water Quality and Water Quantity (interrelated) 2. Clean Water Act’s TMDLs and implementing the Basin Approach to Water Quality Management 3. Safe Drinking Water Act’s Source Water Assessment Program 4. Water Supply/Sanitation issues (infrastructure development needs) a. Small Community Water Systems Capacity Development i. Operational ii. Managerial iii. Financial b. Failing septic systems/Unsewered Communities 5. Definition of Statutory terms (i.e., "beneficial use", aquifer mining", etc.) to provide guidance for water uses/priorities C. Opportunities to Address These Issues ("pay me now or pay me later") 1. Comprehensive, Integrated Basin Management (MDEQ’s Basin Approach) 2. In addition to federal and state agencies, MDEQ ought to pursue heightened roles for basin-specific organizations in developing and implementing specific basin management plans. a. Mississippi’s releveant "Special Purpose" Districts and local agencies with water and related land management authority b. Existing, pending and proposed locally-led watershed and sub-watershed development projects 3. Initial investments of time and resources to identify, collect and standardize available data should help target limited financial and personnel resources and show long term benefits (Scientific Information Management Systems/Geo-Spatial Technologies)
A tethered acoustic doppler current profiler platform
Year: Authors: Storm J.B., Turnipseed D.P.
Acoustic Doppler Current Profilers (ADCPs) transmit sound into the water and receive echoes from particles suspended in the water. The frequency shift between the transmitted sound and echoes (known as the Doppler effect) is used to compute the velocities of the particles and the water in which they are suspended. In 1994, the U.S. Geological Survey Mississippi District began using a 600-kilohertz (kHz) broadband model ADCP to routinely measure river discharges at streamflow-gaging stations. Use of the ADCP makes measuring discharge safer and more accurate than was possible with conventional methods. For making discharge measurements on rivers in Mississippi, the ADCP has been deployed from custom-fitted 14- , 18- and 22-foot aluminum boats. Currently discharge ratings at 11 streamflow-gaging stations are maintained by using ADCP discharge measurements. In 1999, the USGS Mississippi District purchased two new-model ADCPs with 600-kHz transducer assemblies. The new ADCP model is smaller and lighter than the earlier broadband model. The smaller size of the new ADCP model, coupled with existing radio-control technology, has allowed the development of an innovative tethered platform for discharge- measurement applications. This new platform allows for the measurement of discharge at rivers with a minimum average depth of 6 feet in the cross section where conventional streamgaging methods have historically been used from bridges and where lack of access prevents the use of an ADCP from a manned boat. The platform was designed as a safety consideration and reduces the time and personnel needed to make discharge measurements from bridges. The tethered platform is of a tri-hull design. The tether is used to raise and lower the platform and to guide the deployed platform from the upstream or downstream side of a bridge. The data are transmitted from the platform by using two 900-megahertz radio modems, one on the tethered boat connected to the ADCP and the other on the bank connected to a lap-top computer that runs the ADCP software and collects and processes measurement data. The modem along with a 26-amphere battery powering the ADCP is housed on the tethered platform. To make a discharge measurement, the platform and ADCP are hand carried to the bridge where they are deployed over the guard rail into the stream. Once in the water, the platform is pulled by the tether to a starting point at the edge of the water. When the operator of the computer is ready, a signal is given to the boat operator to begin a traverse (a single traverse across the river with an ADCP, resulting in one measurement of discharge, is called a "transect"). Measurements are made according to quality-assurance procedures published in, "Quality-Assurance Plan for Discharge Measurements using Broadband Acoustic Doppler Current Profilers." (USGS Open File Report 95-701).
Simulations of flooding on Tchoutacabouffa River at State Highways 16 and 68 at D’iberville, Mississippi
Year: Authors: Winters K.E.
The Mississippi Department of Transportation (MDOT) proposes to relocate State Highways 15 and 67 in the Tchoutacabouffa River floodplain near Dlberville, Miss. During large floods, a substantial amount of flow crosses the existing roadway near the northern edge of the floodplain. The proposed relocation on the northern side of the floodplain upstream of the existing alignment would force flows on the northern floodplain through the existing main- channel bridge at the southern edge of the floodplain. The MDOT is concerned that the proposed alignment may cause excessive backwater upstream of the site during large floods. The MDOT has proposed four alternative hydraulic arrangements for the proposed alignment. Computation of backwater for the existing conditions and the alternative proposed conditions is complicated by the State Highway 15 and old State Highway 15 embankments located about one-half mile downstream of the State Highways 15 and 67 crossing. In 1999, the U.S. Geological Survey (USGS), in cooperation with the MDOT, used a two-dimensional flow model to analyze the flood hydraulics in the Tchoutacabouffa River Basin. PurDose and Scope This report presents the results of a two- dimensional flow study of the Tchoutacabouffa River at State Highways 15 and 67 near Dlberville, Miss. Water-surface elevations and horizontal velocities for the 100-year flood were simulated for former, existing, and alternative proposed conditions by using a two-dimensional finite-element surface-water model. Computed water-surface elevations throughout the study reach are given for each simulation. Flow distributions are given for the existing and proposed alignments, and selected velocity data are presented. This report also discusses the collection of topographic and bathymetric data used in the study, development of the model grid, and calibration and verification of the model by using discharge measurements and flood- profile data. All elevations in this report are in feet above North American Vertical Datum of 1988 (NAVD of 1988).
Concentrations of organic compounds in bed sediment in the Mississippi Embayment study unit
Year: Authors: Bryson J.R., Wates L., Kleiss B.A.
In 1991, the U. S. Geological Survey (USGS) began the National Water-Quality Assessment (NAWQA) Program to describe current water- quality conditions in a large part of the nation’s streams, rivers, and aquifers. The purpose of the NAWQA Program is to characterize current wa- ter-quality conditions, to observe any changes in water-quality over time, and to improve the un- derstanding of natural and anthropogenic factors that influence water-quality. The study incorpo- rates more than 50 of the nation’s largest river basins and aquifer systems; one of these basins is the Mississippi Embayment (MISE) Study Unit. In 1995, as a part of the MlSE Study Unit evaluation, the USGS collected bed sediment from 15 sites that represented a variety of land use and streams throughout the study unit (fig.1). More than 85 percent (median value) of the land in the MlSE study unit is used for agri- culture and includes row crops, grain crops, pasturelhay, and other grasses. The remaining land IS used for forestry, wetlands, or open wa- ter. The sampling of bed sediment is important be- cause the chemistry of bed sediment can pro- vide insight about the environment surrounding a stream. In addition, it is important to under- stand how the concentrations of potential toxins attached to sediment could be available to biotic communities and how they could cause envi- ronmental effects. The concentrations for 32 or- ganic compounds were analyzed in this study. This paper focuses on the compounds present in concentrations above the reporting limit that also have applicable guidelines.
Hydrogeology of the Mississippi River alluvial aquifer in Northwester Mississippi
Year: Authors: Arthur J.K.
The Mississippi River alluvial aquifer is part of the large aquifer system that underlies the Mississippi River alluvial plain in parts of six States in the Mississippi embayment. In northwestern Mississippi, the Mississippi alluvial plain is a lens shaped area that includes all or part of 19 counties covering about 7,000 square miles (fig. 1). Locally this area is known as the Delta. The Delta extends from the Mississippi- Tennessee border at Memphis, Tennessee, about 200 miles southward to Vicksburg, Mississippi. At the widest point, about midway between Memphis and Vicksburg. the Delta is about 70 miles wide. The western extent of the Delta is the Mississippi River, and the eastern extent is the loess-capped Bluff Hills. The Delta land surface has very little relief, and slopes gently at about 0.5 foot per mile from about 200 feet above sea level at the northern end near Memphis to about 80 feet above sea level near Vicksburg. The Bluff Hills escarpment provides an abrupt transition in topography from the alluvial plain by rising 100 to 200 feet above the alluvial plain. The Yazoo-Yalobusha- Tallahatchie-Yocona-Coldwater River system drains the eastern part of the Delta and a large upland area to the east of the alluvial plain. The Sunflower-Bogue Phalia River system drains most of the central and western part of the alluvial plain outside of the Mississippi River levee system. All the water drained by the Sunflower-Bogue Phalia River system originates within the Delta and flows into the Yazoo River just north of Vicksburg. The Delta has many oxbow lakes that store large quantities of water, but the largest of these crescent-shaped lakes are old meanders of the Mississippi River. Five of the largest lakes are Horn Lake in DeSoto County, Moon Lake in Coahoma County, Lake Bolivar in Bolivar County, Lake Washington in Washington County, and Eagle Lake in Warren County (fig. 1). The climate in the Delta is humid subtropical. Average annual temperature ranges from 62 degrees Fahrenheit near Memphis to 66 degrees Fahrenheit near Vicksburg (Krinitzsky and Wire 1964). Average annual precipitation in the Delta is about 52 inches with very little spatial variation. Most of the precipitation, about 62 percent, occurs in the winter and spring. The fall season has the least precipitation comprising about 17 percent of the annual total. The alluvial aquifer is the most heavily pumped aquifer in Mississippi and supplies most of the water used for agriculture and industry in the Delta. Only the city of Vicksburg and the Eagle Lake Water Association use water from the alluvial aquifer as a drinking water source. Vicksburg’s annual water use is less than 1 percent of the annual total pumpage from the alluvial aquifer. Most of the pumpage from the alluvial aquifer is for agriculture. The Delta is the economic center for agriculture in Mississippi, producing about all of the rice grown in the State, about 96 percent of the catfish, about 79 percent of the soybeans, and 72 percent of the cotton. Water for catfish and rice production accounts for most of the agricultural ground-water demand in the Delta. More than half of the catfish pond acreage in the Delta is in Humphreys, Sunflower, and Leflore Counties. Farms in Bolivar, Sunflower, and Washington Counties produce more than half of the rice produced in the Delta. Irrigation of cotton, soybeans, and corn during periods of deficient rainfall also contributes to the agricultural demand for water from the alluvial aquifer. Since fall 1980, personnel from the U.S. Geological Survey (USGS), the Mississippi Department of Environmental Quality, Office of Land and Water Resources (OLWR), and the Yazoo Mississippi Delta Joint Water Management District (YMD) have made water- level measurements at more than 300 observation wells in the alluvial aquifer during the spring and fall of each year except in 1987 and 1988 when only fall measurements were made. The water-level measurements were valuable in helping to conceptualize the regional flow characteristics of the alluvial aquifer. From 1995 to 2000 the USGS, in cooperation with the OLWR, conducted a study to better understand the hydrology of the alluvial aquifer flow system in northwestern Mississippi and to construct a computer model of the flow system. Hydrologic information and field assistance for the study were provided by the OLWR, the YMD and the Natural Resources Conservation Service. This paper presents a regional overview of the hydrology of the alluvial aquifer as determined by data review and by field investigations.
A separations-based sensor for monitoring NPK in groundwater
Year: Authors: Clarkson J., Liu Y., Wipf D., Henry C.
INTRODUCTION: The analysis of inorganic ions in groundwater supplies is an important issue for monitoring water quality. Ideally, in situ monitoring would allow fast response and easy tracking of non- point source pollution from species such as nitrate, phosphate, and potassium (NPK). Current analytical methods are not suitable for multi-analyte in situ remote sensing. lon- selective electrodes (ISE) and ion- chromatography (IC) are the most common methods of measuring inorganic ions such as nitrate, phosphate, and potassium (Jackson et al. 2000; Karmarkar 1999; Norkus et al. 1996; Schwarz et al. 2000). Both of these methods are limited. ISE can only measure one species at a time plus it frequently suffers from interference from other species in solution. IC is the most powerful of the two methods for the determination of inorganic ions, providing simultaneous analysis of all inorganic cations or anions. There are limitations to IC. First, the equipment is large and expensive making a field portable unit impractical. Second, two separate analyses must be performed to determine the levels of anions and cations. Therefore, new methods, such as capillary electrophoresis, are being explored as alternative analysis methods. Capillary Electrophoresis (CE) is a separation method based on the differential rate of migration of charged species in a capillary filled with buffer solution across which a dc field has been applied (Dasilva and Dolago 1998; Fukushi et al. 1999; Kaniansky et al. 1999; Pacakova et al. 1999; Valsecchi et al. 1997). CE uses electroosmotic flow (EOF) that allows cations, anions, and neutral species to be separated simultaneously. EOF results from the movement of a charged interfacial layer under the influence of a large external potential applied across the capillary. Above pH 3, the inside wall of the channel is negatively charged due to ionization of the surface bound silanol groups. Buffer cations congregate in an electrical double layer adjacent to the negative surface. The cations in the outer layer flow toward the cathode, or negative electrode. The cations are solvated thus causing flow of the solvent. Capillary electrophoresis on microchips has become an important area of research in analytical chemistry (Harrison et al. 1993; Jacobson and Ramsey 1997; Manz et al. 1992). The idea of a lab-on-a-chip, where all separation and analysis steps are accomplished on a single microchip, is becoming a reality. Miniaturization of the components is the limiting factor in the lab-on-a-chip idea. Microchip capillary electro- phoresis is less expensive, more durable, much faster than conventional CE and provides more efficient separation. Several detection methods have been applied to microchip CE. Optical detection methods have been the major detection mode for microchip CE, and laser induced fluorescence (LIF) has been the favored method producing detection limits in the picomolar range (Harrison et al. 1993; Jacobson and Ramsey 1997; Manz et al. 1992). The size and cost of the instrumentation such as lasers required to carry out these detection methods negates some of the benefits of miniaturization. Electrochemistry has been demonstrated as a successful detection method for microchip CE (Henry et al. 1999; Martin et al. 2000; Wang et al. 1999; Woolley et al. 1998). Unlike optical and mass spectrometry detection, it is easily miniaturized to match the microchip size. Furthermore, electrochemistry is extremely sensitive for easily oxidized species. Conductivity detection methods are thought to be a universal detection method for separation techniques. Conductivity is a bulk solution property unlike electrochemical methods where reduction and oxidation occurs at the surface of the electrodes. Conductivity is based on ionic mobilities unique to each species under observation. Previous reports have shown a limit of detection of sodium to be 0.43 mM (Kaniansky et al. 2000). Here we report the detection of working concentrations of 100 pM of hydroquinone and sodium phosphate separations using microchip CE with in-channel conductivity detection.
Use of riboflavin for enhancing phototransformation of 2,4,6-Trinitrotoluene (TNT) in a freshwater environment
Year: Authors: Hwang H.M., Cook S., Cui H.
2,4,6-trinitrotoluene (TNT) is a conventional explosive used by military forces worldwide, causing serious contamination of soil and groundwater (Boopathy et al. 1994). Environmental transformations of TNT and methods of remediation have been extensively studied (Schmelling and Gray 1995). The photochemical degradation of TNT was considered both as a primary treatment technology and as a pretreatment to biodegradation. Several strategies such as direct solar photolysis, UV-peroxide. UV- ozone, and Ti02 photocatalysis have been developed for the treatment of TNT- contaminated water (Schmelling and Gray 1995). Exposure of TNT to sunlight or near UV radiation results in rapid conversion of TNT into a variety of aromatic photolysis products such as 2,4,6-trinitrobenzoic acid, 1.3.5 trinitrobenzene. 3,5-dinitroaniline, 2,4.6-trinitrophenol, 4-amino-2,6- dinitrotoluene, 2,4-dinitrobenzoic acid, 2,4,6- trinitrobenzaldehyde, 2,4,64rinitrobenzyl alcohol, 4.6-dinitroanthranil, 2,4,6- trinitrobenzonitrile, and azoxydimers (Schmelling and Gray 1995; Kaplan. Burlinson, and Sitzmann 1975; Kearney, Zeng. and Ruth 1983; Crosby 1998; Lang et al. 1998). depending on the photolysis condition. Each method has its own advantages and disadvantages with varying degrees of success. Therefore, there is a need to explore more efficient strategies for the remediation of TNT. Photosensitizers have been used to facilitate the photochemical degradation of some organic compounds. It is proposed that photosensitizers absorb light energy, transform it into chemical energy, and transfer that energy under favorable conditions to photochemically unreactive substances. The mechanism may be involved in redox reactions (Larson, Stackhouse. and Crowley 1992). Riboflavin as a photosensitizer has been reported to sensitize the photochemical degradation of many compounds in aqueous solutions (Mopper and Zika 1987; Hwang et al. 2000). Riboflavin is easy to handle and environmentally benign, making it attractive for the treatment of environmental water. In this paper, the effect of riboflavin on the fate of TNT in a natural water environment was studied. The relative contribution of photolysis, microbial assemblages and freshwater matrix to TNT degradation was examined in the absence and presence of riboflavin. The rates, extent and products of TNT transformation under different experimental conditions were determined by high-performance liquid chromatography. The transformation of riboflavin under different experimental conditions was also compared by use of fluorescence analysis.
Use of riboflavin as a photo-sensitizer for enhancing atrazine degradatin in a freshwater environment
Year: Authors: Glover H., Hwang H.M., Zeng K., Cui H.
Atrazine is a herbicide used to selectively control broadleaf weeds in agricultural fields. Most atrazine is released to the environment through agricultural use as a herbicide and in effluents from manufacturing facilities. Current U.S. estimations of application are 80 million pounds per year. Generally, annual runoff losses of atrazine are 2% to 5% of the total applied. Atrazine is toxic, often bioaccumulative and persistent (Fernando et al. 1992). Consequently, the search for effective remediation methods of removing atrazine from water is important. Photolysis and microbial degradation have been recognized as important removal forces of many organic pollutants in natural surface waters (Hwang et al. 1986; Hwang et al. 1998; Hwang et al. 2000). Photodegradation of triazine herbicides under direct solar light occurs very slowly (Trotter et al. 1990). In natural aquatic environments, photodegradation of organic pollutants can be strongly enhanced by photosensitizers (Tsao and Eto, 1994). Riboflavin as a photosensitizer has been reported to enhance the photochemical degradation of many compounds in aqueous solutions (Mopper and Zika, 1987; Hwang et al. 2000; Cui et al. 2001). Riboflavin is easy to handle, economical, and environmentally benign, which makes it attractive for treatment of environmentally contaminated water; however, the photoinduced toxicity to microbes by organic contaminants and riboflavin has been reported (Hoffmann and Meneghini, 1979; Khan et al. 1973). The wide range of reports on this problem suggests that these compounds may affect environmental health. In this work, microbial bioassays were used to measure toxicity of the study chemicals based on the assumption that microorganisms can act as surrogates for higher organisms in the ecosystem. The relative contribution of microbial assemblages to the riboflavin-sensitized phototransformation of atrazine in a natural water environment was explored using high performance liquid chromatography. The effect of the metabolite mixture on microbial populations during phototransformation was examined using spread plate analysis and radiotracer mineralization techniques.
NWISWEB: The Web server for the National Water Information System
Year: Authors: Welch H.L.
The U.S. Geological Survey (USGS) maintains a distributed network of computers and fileservers for the storage and retrieval of water data collected through its activities at approximately 1.5 million sites around the country. The USGS is testing a new web server (NWISWeb) for its National Water Information System (NWIS) data that includes surface water, water quality, and ground-water data, and site related information. NWlSWeb was created to provide both internal and external users of USGS water information with an easy to use, geographically seamless interface to the large volume of USGS water data. Data are updated from the NWlS sites on a regularly scheduled basis, and real-time data are transmitted to NWlSWeb several times a day. NWlS data come from all 50 States, selected territories, and border stations. Of the sites with NWlS data, 1.2 million are wells, 350,000 are water-quality sites, and 19,000 are streamflow sites, of which over 5,000 are real-time sites. NWlSWeb contains data for about 4.3 million water-quality samples, including about 64 million individual analyses. STRUCTURE AND PURPOSE Online access to the NWlS data is organized around five categories: real-time, site information, surface water, ground water, and water quality (fig. 1). Users can specify search criteria in any of the categories based on individual need. NWlSWeb provides several output options for the resulting data: real-time streamflow, water-level and water-quality graphs, data tables and site maps; tabular output in html and ASCII tab delimited files; and lists of selected sites as summaries with reselection capabilities for details.
Pascagoula River flow augmentation during the record drought of 2000
Year: Authors: Branch C.T., Cobb D.H.
In the months between January 01, 1999 and December 31,2000 Southeast Mississippi was in the midst of a drought of unheard proportions. During this 24-month time frame, this area of the state ran a precipitation deficit in excess 24 inches below normal. During thissame period, the deficits exceeded even those of the previous drought of record in 1952 and 1953. The lack of rainfall combined with intense summer heat meant inevitable declines in stream flows throughout the Pascagoula River Basin. It became apparent in the summer of 2000 that barring an extreme climatological event, the Pascagoula River was destined to plummet below its previously established low flow record of 707 cfs at the Merrill Gauging Station. In order to avertwhat could potentially be avery undesirable condition for both the environmental resources within the Pascagoula River Basin and businesses in Jackson County, the Commission on Environmental Quality issued an order directing that in order for withdrawals to continue at Cumbest Bluff below the previously recorded minimum, flow augmentation would have to be provided at the point of extraction equal to the amount of withdrawal. In September 2000, the Office of Land and Water Resources (OLWR). United States Army Corpsof Engineers - Mobile District (USACOE), Pat Harrison Water District (PHWD), and the Jackson County Port Authority (JCPA) officials met to establish criteria and define a mechanism by which auxiliary flows could be provided from Okatibbee Reservoir north of Meridian MS, in Lauderdale County, down its natural watercourse to the pumping station at Cumbest Bluff, located in Jackson County. An agreement was reached, and the appropriate contractual documents signed. The following week, the OLWR began monitoring conditions in the entire Pascagoula River Basin and making determinations as to the appropriate weekly releases from Okatibbee Reservoir.
The OFAER Poultry Program After 6 Months
Year: Authors: Horn C.R.
OFAER Goals: -Promote Environmental Stewardship -Minimize Livestock Production Effects on Watersheds -Improve Public Perception of Livestock Production -Move Agricultural Toward Becoming a Self-Regulating Industry On-Farm Assessment and Environmental Review -Helping to improve environmental performance in poultry production -Information -Education -Demonstration -On-Farm Assessment
Public release of the National Water Information System
Year: Authors: Welch H.L., Plunkett M.L.
The U.S. Geological Survey (USGS) is now offering public access to its nationwide database, which includes information pertaining to ground water, surface water, and water quality. Currently, the USGS Mississippi District maintains a local web page, http: //ms.water.usgs.gov/, that provides access to surface-water data and to a limited amount of ground-water and water-quality information. The http://water.usgs.gov/nwis. offers far more extensive information including site descriptions, historical water levels, historical and current values for surface-water, and water-quality data. The NWlS web site also allows the user to customize inquiries based on the information needed. The new database is a powerful tool that provides everyone access to water information for all of the United States. new national web page.
Record drought conditions and effects on Mississippi streams and lakes
Year: Authors: Hardin D.L., Long L.G.
Beginning in January 1999 and continuing through November 2000, the state of Mississippi experienced one of the worst, and arguably the worst, droughts ever for the state. While the effects of this drought were experienced throughout the state, the southern part was especially hard hit. The drought of 1952-1953 is considered the "drought of record" for Mississippi. The cumulative rainfall deficits for 1999-2000 were comparable to those recorded for 1952-1953. For the streams and rivers in all areas of the state, the rainfall deficit for 1999-2000 resulted in record low flows, both daily and all-time lows. The low flows in the streams and rivers caused hardships for individuals and industries dependent on surface water. Cease pumping orders were issued on numerous streams because of low flow conditions.
Impact of drought conditions on Mississippi streams and rivers in 2000
Year: Authors: Turnipseed D.P., Baldwin W.T.
USGS streamgage records indicate droughts have affected Mississippi streams during 1940- 44, 1951-57, 1962-71, and 1980-88. During the drought that began in late summer 1999 and continued through fall 2000, many areas of Mis- sissippi experienced near record drought condi- tions causing concern to many private and public interests. Droughts are normal, recurring hydrological events caused by deficiency of precipitation over an extended period of time, which can have ad- verse effects on availability and use of water. Much of Mississippi continued to experience drought conditions through late winter 2000. Data on minimum streamflows are an important factor for determining the regulation of flow- control structures, effluent, surface-water with- drawals, and other water-management decisions during droughts. Data on minimum streamflows become paramount during drought conditions. The USGS maintains a Statewide network of streamgages providing Federal, State, and local agencies, institutions, and the private sector with accurate, reliable, and timely river stage, river discharge, and other hydraulic and hydrologic parameters for many water-use and design needs. All of the streamgages discussed in this report may be accessed in real-time mode through the internet at the following address: http://water. usqs.qov/ms/nwis/ This report presents selected streamflow data collected at gages on streams affected by se- vere drought conditions in Mississippi during the 1999-2000 water years. Discussion of drought conditions presented for the Yazoo River Basin are limited to data collected in the headwaters of the basin at gages upstream of the Mississippi River alluvial floodplain. No discussions are presented for tidally affected flows near the Gulf of Mexico. Comparisons of 1999 and 2000 wa- ter-year data to low-flow characteristics at se- lected streamgages to other period-of-record low-flows at selected gages in the State are also presented. The data are presented in a basin- by-basin analysis.
Capturing the benefits of site-specific management: Is it time for a public policy?
Year: Authors: Hudson D., Hite D.
INTRODUCTION U.S. agricultural producers have intensified their use of agricultural chemicals over the past 50 years, resulting in increases in agricultural non- point pollution (NPP) in the form of herbicide, pesticide, sediment, and especially, nutrient, runoff. It is generally recognized that significant mitigation of pollution from point sources has been achieved since the implementation of the 1972 Clean Water Act, but NPP still poses a significant problem. In fact, the U.S. Environ- mental Protection Agency found that over one- third of all streams, lakes, rivers, and estuaries did not support their designated uses in 1996 (USEPA), and NPP was believed to be the ma- jor source of those deficiencies. Agriculture is generally recognized as the largest contributor to NPP (USEPA). Public awareness and concern over perceived environmental degradation have helped to spur scientific developments and use of more envi- ronmentally "friendly" chemicals. In addition, new water quality rules in the form of Total Maximum Daily Load (TMDL) standards for wa- tersheds will intensify regulatory attention on agricultural practices. Thus, additional means to reduce NPP, such as best management prac- tices and site-specific management technologies have been developed and suggested for adop- tion to agricultural producers. Site-specific management (SSM) refers to a collection of techniques and technologies rang- ing from modern computer assisted mapping and guidance and variable rate applicators (seed, fertilizer, and pesticides) to more rudi- mentary technologies such as soil sampling and testing (Khanna, Epouhe, and Hornbaker). A primary objective of SSM is the management of in-field variability of soil characteristics and con- ditions. SSM is believed to improve nutrient in- take and input productivity by applying a more optimal amount of inputs on a much smaller scale of management (sub-field level). Several studies, however, point to the conclusion that profitability of SSM for producers is questionable (Carr et al.; Morris and Blackmore; Swinton and Lowenberg-DeBoer; Sawyer). Questionable (or highly variable) returns leads to a lower prob- ability of adoption, which appears to be the case for SSM (Khanna, Epouhe, and Hornbaker; Hudson and Hite). Several studies, however, point to the potential environmental benefits of SSM (Hite, Hudson, and Intarapapong, 2000a; Ofice of Technology Assessment; Fuglie and Bosch; Khanna and Zilberman; Oriade et al.; Schnitkey and Hop- kins). The environmental benefits are derived from reduced chemical runoff and leaching through improved matching of chemical applica- tion with crop needs. Assuming that these envi- ronmental impacts are tenable, they create a positive externality of reduced pollution that ac- crues to the public, but currently provides no added monetary incentive for producers to adopt SSM. t could be argued that this pollution is, in fact, a negative externality and that reducing pollution reduces the negative externality. We are arguing from the status quo of pollution so that reduced pollution becomes a positive exter- nality. Given that current adoption appears to be low, and the profit motive for adoption appears to be weak, can public subsidization of SSM be used to capture the positive externality of reduced agricultural pollution? We recently conducted two surveys in Mississippi-one for consumers and one for producers-to examine both public demand for pollution abatement and willingness to pay (VvTP) for subsidization of SSM, as well as producer VvTP for technology under alterna- tive subsidization schemes. Our purpose here is to outline those results as a hypothetical public policy for SSM adoption.
Construction and induction of hybrid bacilli for catabolizing both nitroaromatic and polyaromatic hydrocarbons
Year: Authors: Yang W.H., Yang J.R.
Aromatic hydrocarbons particularly insoluble polyaromatic hydrocarbons (PAHs) have been accumulated petroleum as the results of metabolic activities of living organisms on this planet. Serious contamination of environment with those compounds has been resulted from the explosive use of petroleum by human activity. The extensive application of those PAHs in industry for wood preservation and road construction seriously contaminated the environment . Rosenfeld and Plumb (1991) reported that PAHs were present in over 20% of soil components in the wood treating site tested. PAHs contamination of soils and ground water are of particular concern because many of those compounds are known as carcinogens. Most of nitroaromatic compounds are artificially produced in large quantity by industry for plastics, explosives, pharmaceuticals, and pesticides (Bryant and DeLuca, 1991; Hallas and Alexander, 1983; Kedderis et al., 1988; Nishino and Spain, 1993). As a result, large amount of nitrobenzene is contaminating the environment at a rate of tens of millions of pounds annually (U.S. Environmental Protection Agency, 1978). In addition, nitrated polycyclic aromatic hydrocarbons are also formed during a variety of combustion processes causing serious environmental pollution (Rafii, et al.. 1991). Aerobic degradation of aromatic hydrocarbons by a microorganism was first demonstrated in the early 1900s. Since then, various strains of bacteria and fungi capable of catabolizing aromatic hydrocarbons were isolated (Gibson et al. 1984). Biodegradation of aliphatic hydrocarbons (gasoline and diesel oil ) by bacteria were also developed contributing greatly in bioremediation of enviroment of disaster by oil spill (Reisfeld et al. 1972; Rosenberg et al. 1979 a, b; Britton 1984; Shabtai and Gutnick. 1985; Yang et al. 1996a,b). The application of gene- recombination to obtain hybrid bacteria for aromatic hydrocarbon catabolism was first demonstrated in Pseudomonas (Duque et al. in nature mainly as a part of petroleum hydrocarbons (Yang et al. 1996a, b), and benzene (Yang et al. 1997) can be catabolized by hybrid of B. mycoides following transformation and gene-fusion of bacilli with either pTV,Ts or pLTV,. The object of the current study is to investigate whether biodegradation of both nitroaromatic and polyaromatic hydrocarbons can be achieved in bacilli following gene-recombination with plasmids either by transformation or gene-fusion. Another object of current study is to examine which catabolic pathways are more favaorable for biodegradation of nitroaromatics or polyaromatics.
Drought conditions in the Pascagoula River Basin in Mississippi in 2000
Year: Authors: Baldwin W.T., Turnipseed D.
The drought in Mississippi that began in late summer 1999 and continued through the fall of 2000 has resulted in the lowering of streamflow in most streams in the Pascagoula River Basin to record lows. The US. Geological Survey currently operates a streamflow-gaging network of 22 continuous streamgages and 12 crest- stage gages in the Pascagoula River Basin. The drainage area of the Pascagoula River Basin is about 9,500 square miles. The length of the river upstream of its confluence with the Mississippi Sound is about 265 miles. This poster presents selected data on streamgages affected by severe drought conditions in the Pascagoula River Basin in Mississippi during the 1999-2000 water years. Comparisons of 1999-2000 low-flow characteristics at selected streamgages to other period-of-record low flows at selected gages in the Pascagoula River Basin are presented. In Mississippi, the 7-day, 10-year low flow (7Q10) is the established minimum flow characteristic used by the Mississippi Department of Environmental Quality and other agencies to permit the rate at which waste effluent is discharged into streams and to set permit limits for water withdrawals from streams. Provisional discharge data indicate that at 20 of 22 streamgages in the basin, streams flowed at less than 7Q10 values during the 2000 water year, and at 19 of these streamgages, streams flowed at record low rates. The range in the period of record for the 22 active continuous discharge gages in the basin as of the 2000 water year is 5 to 69 years, and the average period of record is 41 years.
Ecological and water quality effects of the Mississippi Delta management systems evaluation area on oxbow lakes
Year: Authors: Knight S.S., Welch T.D.
Over the course of the past century, aquatic habitats have declined worldwide. Much of this loss has been attributed to draining and clearing for agriculture as well as non-point source pollution associated with agricultural runoff. The Mississippi Delta MSEA (Management Systems Evaluation Area) is a competitive agricultural systems-based research project designed to address the problems associated with these non-point source pollutants. This project is unique among MSEA projects, both because of its location in the Mississippi River alluvial plain and its strong ecological research component. Experimental design of the Mississippi Delta MSEA called for the development of land and cultural treatments targeted to reduce sediment and associated pollutants entering watershed oxbow lakes. Changes in lake water quality and fisheries characteristics were, and are still being used as measures of management success. Analyses of water quality prior to the implementation of best management practices (BMPs) indicated lakes that were stressed and ecologically damaged due to excessive in- flowing sediment. significant improvements in water quality were realized through the use of cultural and structural BMPs. Sediments were decreased 34 to 59%, while Secchi visibility and chlorophyll generally increased. The most dramatic improvements in water quality occurred in Thighman and Deep Hollow, which featured cultural practices and combinations of cultural and structural practices, respectively. Reducing suspended sediment concentrations in these oxbow lakes resulted in conditions favorable for phytoplankton production. Increases in phytoplankton production resulted in increased chlorophyll concentrations and higher concentrations of dissolved oxygen, leading to improved secondary productivity. Prior to implementation of BMPs, species richness was relatively low for all three MSEA lakes and sports fishes were generally poorly represented with the exception of white crappie and channel catfish. No largemouth bass were collected from Beasley or Thighman lakes. Post BMP fishery surveys indicate successful renovation of lakes protected with cultural or structural and cultural practices. Following renovation, fish catches and diversity were highest in Thighman and Deep Hollow while Beasley showed a decline in both standing stock and diversity. Bass populations lacking in two of the lakes before renovation and restocking were successfully reestablished in Deep Hollow and Thighman. In all likelihood, restocking in Beasley Lake failed due to continuing poor water quality despite the presence of structural BMPs. Results indicate that cultural BMPs may play the more vital role in improving lake water quality and may be needed in addition to structural measures to ensure improved fisheries in oxbow lakes receiving agricultural runoff.
Environmental fate of fluometuron in soil influenced by best management practices (BMPs)
Year: Authors: Blanche S.B., Shaw D.R., Shankle M.W., Kingery W.L., Massey J.H.
Fluometuron is an effective herbicide for annual grass and broadleaf weed control in cotton. Several fluometuron applications applied per growing season may include a preemergence, postemergence when cotton is 7.5 to 15 cm, and postemergence at lay-by (with the last cultivation). The mode of action is inhibition of photosynthetic electron transport by binding to the D1 protein of photosystem II and blocking electron transport from Qn to Qg (Ahrens, 1994). Fluometuron was labeled for use in 1965 (Timmons, 1970) and is one of several compounds that belong to the herbicide group known as the phenylureas or substituted ureas. These compounds have three hydrogen atoms of urea replaced or substituted with a variety of carbon chains and rings. Fluometuron is unique from other compounds in this group due to a trifluoromethyl group at the meta position of the phenyl ring (Rickard and Camper, 1978). Fluometuron is considered to be a nonionic molecule that does not ionize over a wide pH range (Patterson et al., 1982). Water solubility is 90 mg L ’ at 20 to 25 C and is categorized as moderately water soluble (Weber, 1972). Fluometuron was the herbicide of choice to evaluate because cooperating producers at all the MD-MSEA locations apply fluometuron, and detectable levels have been reported in surface water (Coupe et al.. 1998; Pereira and Hostettler, 1993). Previous research suggests that herbicide and sediment in runoff is reduced as it moves through grass filter strips and riparian areas. Therefore, research objectives were: to characterize soil properties within different areas of a new (c 1 yr) grass filter strip, established (> 5 yr) grass filter. and a riparian forest to determine the impact of different BMPs on soil properties and the spatial distribution of soil particles within BMP areas; and determine fluometuron adsorption and degradation to these soils to assess the ability of soil from these BMPs to retain fluometuron.
The benefits of buffer strips on water quality: A simulation in the classroom
Year: Authors: Larry S., Walker N., Brown T.
STRIDE, the Student and Teacher Research Institute - the Delta Experience, has been a collaborative effort between Mississippi State University and the Mississippi Delta Management Systems Evaluation Area (MSEA) and targets Mississippi Delta schools and the environment. The STRIDE project was funded in part by the National Science Foundation and was designed to introduce agricultural and environmental research methodology to middle school teachers and students. Teacher/student teams work on existing scientific projects in the field and in the laboratories of MSEA scientists. MSEA was established in part to improve water quality in the Mississippi Delta through and development and practice of best management practices in agriculture, with the hope of reducing adverse effects on ecological processes. Many state-and federal-government agencies, associated scientists and several Mississippi Universities, which participate in the MSEA project, have assisted with STRIDE. Teacher/student teams from Mississippi Delta middle schools were selected each summer from 1998-2000 to participate in the STRIDE program. Research collaborations extending from STRIDE experiences have been presented at various science fairs, school-board meetings and past Water Resource Conferences. One example of a research project developed from such experiences is presented here by Ms. Shantell Larry, science teacher at Threadgill Jr. High School in Greenwood, Mississippi, and her students Nina Walker and Tashunda Brown. This team proposed to investigate the use and efficiency of filter strips in obtaining netter water quality. It is hypothesized that filter or buffer strips can help manage and improve water quality by reducing the amount of sediments, which would include potentially harmful herbicides and pesticides, released into run-off and water collection sties. Two representative watersheds were constructed in the classroom from household items. A buffer strip was placed in the path of water run off in the experimental watershed and no buffer strip was placed in the control watershed. Radish seeds were planted and sprouted to represent the agricultural crop and artificial grass represented the buffer strip. Crops were watered, the sediment in run off was collected, and dry weight was recorded every two days. Here we present data taken over a four-week period. Data indicates that buffer strips indeed reduce the amount of sediment released into run-off water and therefore suggest that water quality could be improved by adding the use of buffer strips to best management practices.
The effects of blue lake water quality on catfish fingerlings: A stride project
Year: Authors: Lee R., Adarns S., Muriuki E., Pote J., Thivaudeau G.
The Student and Teacher Research Institute - the Delta Experience (STRIDE): Targeting Mississippi Schools and the Environment project is a collaborative effort between Mississippi State University and the Mississippi Delta Management Systems Evaluation Area (MSEA). Funded in part by the National Science Foundation, the project is designed to introduce research methodology to middle school teachers and students by working side-by-side with MSEA active researchers on their existing projects. One of the objectives of the MSEA project is to improve water quality in the Mississippi Delta through the development of alternative farming systems, which would or is designed to reduce adverse effects on ecological processes. More than 14 agencies and 60 researchers and university faculty assist with STRIDE. Participating agencies on the MSEA project are USDA Agricultural Research Service (ARS), U.S. Geological Service, and Mississippi Water Resources Research Institute. Cooperating agencies include: Delta council, Delta Wildlife Foundation, Mississippi Department of Environmental Quality Control, Mississippi Department of Wildlife, Fisheries and Parks, Mississippi Farm Bureau Federation, Mississippi Soil and Water Commission, US. Fish and Wildlife Services. USDA-Farm Service Agency, USDA-National Sedimentation Laboratory, USDA-National Resources Conservation Service, USDA-Wildlife Services, and Yazoo Mississippi Delta Joint Water Management District. Universities affiliated with the program are the University of Mississippi and Mississippi State University. Teams of one teacher and two high- potentiallhighly-motivated students from schools in the Mississippi Delta were selected to participate in the STRIDE program. To date, three summer workshops have been held. One example of the collaboration between teacher/student teams and MSEA scientists resulting from the 2000 workshop was research done by Rylander Lee, science teacher at Threadgill Jr. High School in Greenwood, Mississippi, and her students Shamika Adam and Elizabeth Muriuki. Lee and her students worked with Karrie Pennington, Natural Resource Specialist at USDA, Mississippi Natural Resource Conservation Service. Using water samples collected from Blue Lake in Greenwood, they studied the effects of water quality on catfish fingerlings over a three-month period. Three collection sites were chosen: an area located at the northern end of the lake, bordered by woodland and natural grass; an area located at the west side of the lake, bordered by a residential neighborhood; and an area located at the southern corner of the lake, bordered by agricultural land and a stream overflow. The objective of the project was threefold: to measure and evaluate basic water quality parameters from samples taken from three specific locations at Blue Lake; to compare measurements and reach conclusions about overall water quality from each site and determine the effect on the catkh fingerlings; and to compare measurement results from the three specific collection sites over the three- month period. Here we present data from the water quality study of Blue Lake, which have implications for ecological and agricultural practices.
Cracking modes of an expansive Mississippi Delta soil
Year: Authors: Wells R.R., Prasad S.N., Romkens M.M.
Modes of cracking in expansive soils of the Mississippi Delta and their impact on infiltration were examined. Preliminary laboratory infiltration studies suggested an evolutionary pattern of the crack network. Subsequent studies were conducted to investigate the primary modes of crack formation the their impact on filtration. Of particular importance in the evolution of the crack morphology , the role of the seal and development of stress within the substrate is discussed. Understanding the developmental aspects of cracked soils permits further development of infiltration relationships that are used to determine the capabilities of cracked soils to transport water and solutes.
Insecticides in runoff from BT cotton in Mississippi Delta management systems evaluation area
Year: Authors: Cullum R.F., Smith, Jr. S.
Runoff samples were collected and analyzed from Bt (Bacillus thuringiensis) cotton and non- Bt cotton fields for insecticides from 1996 through 1999 at the request of the Delta Council. The insecticide analyses included pyrethroid and organophosphate insecticides based on the popularity and use throughout the Mississippi Delta in cotton-producing areas. The purpose of this paper was to present and compare the insecticide concentration data for runoff samples from the Bt-cotton fields to that from non-Bt cotton fields within the Mississippi Delta Management Systems Evaluation project. The use of the genetically engineered Bt cotton plant to produce its own pesticide reduced the volume of pyrethroid insecticides sprayed into the environment at the Beasley Lake Watershed. The reduced application dates and pyrethroid types on the Bt cotton sites as compared to the multiple applications of mutiple pyrethroid insecticides on the non-Bt cotton sites to control the tobacco budworm and bollworm resulted in dramatic reduction of pesticides released into the environment. Even though the non-Bt cotton sites resulted in little to no detects of the pyrethroid insecticides, the Bt cotton site had even lower concentrations in the runoff. Insignificant detects were found with the organophosphate insecticides for boll weevil control from either Bt or non-Bt cotton sites. No detrimental environmental effect from the pyrethroid and organophosphate insecticides was found from water samples of runoff from all tested sites within the watersheds o this study. Other than economics or costs of the Bt cottonseed, reduced pyrethroid types, and reduced applications for budworm and bollworm control in heavily infected areas as compared to the costs of non-Bt cottonseed, the multiple pyrethroid types, and their multiple applications, there is little negative environment effect from either type of cottonseed.
Suspended sediment in runoff from Mississippi Delta MSEA project watershed, 1996-99
Year: Authors: Rebich R.A.
One of the most intensive agricultural areas of the United States is located in northwestern Mississippi, a 7,000-square-mile area locally referred to as the Delta. The fertile soils of the Mississippi Delta produce a variety of crops such as cotton, soybeans, corn, and rice. Similar to other areas of the Nation where agriculture is intense, water resources in the Mississippi Delta are vulnerable to potential adverse environmental effects caused by excessive sediment, nutrients, and pesticides transported from agricultural fields. Suspended sediment-and turbid conditions caused by suspended sediment-is considered one of the primary water-quality concerns in the Mississippi Delta (State of Mississippi 1999). Soil erosion and sedimentation have been well documented as causing declines in fisheries in Delta streams and oxbow lakes by limiting light penetration necessary for photosynthesis in aquatic plants (Cooper and Knight 1978; Knight et al. 1994). The high erosion rates and off-field sediment movement could be linked to farming practices such as conventional tillage (Meyer and Harmon 1978) where soil is disturbed frequently throughout the year, especially during winter and spring when rainfall is greatest. In addition, other contaminants such as nutrients and pesticides can attach to sediment and be transported during runoff events. The Mississippi Delta Management Systems Evaluation Areas (MDMSEA) project began in 1995 to study agricultural nonpoint-source pollution of oxbow lake watersheds. Specifically. the two purposes of the MDMSEA project were to assess the effects of agriculture on water quality and to evaluate best management practices (BMPs) designed to improve water quality. As part of the MDMSEA project, the US. Geological Survey (USGS) began operating an automated streamflow and waterquality sampling network in April 1996 to assess the effects of an untreated system and BMP systems on edge-of-field runoff quality (Rebich 1997). This paper presents selected suspended- sediment concentration and load data for runoff samples collected from nine sites for the MDMSEA project from 1996 through 1999. The paper also presents comparisons of suspended-sediment data from runoff of an untreated field to BMP-treated fields.
Major issues and concerns of the Mekong River, an international river
Year: Authors: Sears P., Chan N.W., Kung H.T.
The Mekong River originates on the Tibetan Plateau, flows through southern China, Myanmar, Thailand, Cambodia, Laos and Vietnam before emptying into the South China Sea (Figure 1). The river establishes the borders between many of the above countries. It is the source of life for all the inhabitants in its basin as major settlements have historically sprung up along its banks, floodplains and estuaries. The river provides water supply for the people, irrigation for agriculture, as a means of transportation, a source of food in fisheries, hydro-electric power, water use for industries, recreation and tourism, and as vital wetland habitats for wildlife. Yet, for millions of years, the Mekong River has been meandering and flowing from Southwest China through Southeastern Asia unhindered and undisturbed by human- made obstructions or diversions (Sears, 2001). Historically, in the past, human adaptation to the river and flood plain environment was manifested in small-scale subsistence agriculture that did not bring about many negative effects. Humans merely adapted to the regimes of the river and co-existed side-by-side with it. However, the Mekong River Basin has undergone profound alterations that have accompanied the changes in land use and the economic development of the region. Amongst other things, the construction of dams, reservoirs and water diversion systems have brought about not only environmental degradation but also increasing environmental hazards such as landslides, sedimentation, water pollution and floods. More significantly, competition and conflicts (internal and external) between neighboring countries in terms of power generation, water use, navigation, fishing and other developments have marked a greater part of the history of this great river basin. Since the Mekong River Commission (MRC) was formed in 1957, it has been the agency in charge of planning and coordination of development of the basin. Amongst other things, the MRC has attempted to develop the basin into a very productive hydroelectric power region. However, lack of funding, war and civil strife, non-cooperation of some member countries, competition in water resources utilization, and other conflicts have curtailed the effectiveness of the MRC.
Ground Water Salinity in the Cockfield Aquifer, Washington County, Mississippi
Year: Authors: Mason P.
The current study focused on Washington County, Mississippi, (Figure 1) and undertook two objectives. The first was to compile and analyze existing data on the hydrogeology of the area in greater detail. The second was to continue, and report results of, the OLWR sampling and well monitoring programs from 1995 through 2000, and to interpret the data in light of more complete hydrogeologic information.
Management of river pollution as a tool in water resources management: Some examples from Malaysia
Year: Authors: Chan N.W., Kung H.T.
Rivers are the life veins of Malaysia, being important "water highways", sources of food and water, draining water-logged areas and being habitats of important ecological systems. The country is drained by 150 river systems, of which 100 are in Peninsular Malaysia and 50 in East Malaysia Sabah and Sarawak (Figure 1). Within these river systems is an estimated 1,800 rivers and major tributaries, with a total length exceeding 38,000 km. The largest river in Malaysia is Sg. Rajang with a catchment area of 51,000 sq. km while in the Peninsular, is Sg. Pahang with a catchment of 29,000 sq. km. By world standards, Malaysian rivers are short and steep (Hj Keizrul Abdullah 1999). Rivers are the main water source contributing about 97 % of water needs in the country. Unfortunately, rivers are also used for a variety of purposes that pollute and degrade them, ultimately threatening both the quantity and quality of their waters. During historical times, rivers were the hub of life with not only the major settlements lining the banks but rivers also plan an important role in the economic and social life of the people (Kennedy 1967). Since independence in 1957, however, Malaysia has developed steadily changing from a rural economy based on agriculture and tin mining to an export based manufacturing economy. Over the last three decades, the transformation has been unprecedented with very rapid urbanization and industrialization (Jomo 1994). The change from rubber estates to oil palm and the opening up of extensive tracts of land by the Federal Land Development Agency (FELDA) coupled with uncontrolled logging transformed the land use from one of mainly forest and food crops to one of estates (cash crops) and townships (International Law Book Services 1991:185). This was followed by expansion of urban commercial and industrial centres. All these developments have overstressed river systems. As a result, many river basins have reached their limits of water supply and are now susceptible to water stress and droughts. The occurrence of low flows is exacerbated when rapid development has produced great amounts of human wastes as well as wastes from all of man’s activities, including agriculture, industrial, commercial and transportation wastes (Kung 1986; Hamirdin 1993). This has resulted in a great number of rivers that are very polluted, some to the extent of being not rehabilitable. Yet, many rivers can be restored and rehabilitated given the right kind of efforts. Deforestation has also led to the opening up of large tracts of land within river basins and this has resulted in not only increased sediment loading in the river systems but also in the aggravation of floods which further pollute the waters (Chan and Kung 2000; Chan, Kung and Wan 2000). Related to deforestation and development of hill land is the high incidence of erosion and landslides (Chan and Wan Ruslan 1997). These events lead to sediment pollution of rivers. Further downstream, the excess runoff from the heavy tropical rainstorms inundate large tracts of land, causing damage and economic losses with significant loss of life (Chan 1995). At other times, low water levels during periods of drought result in water shortages leading to rationing of supply, interruptions to commercial and industrial activities, and losses to agriculture production. Furthermore, the rapid pace of development of the past three decades have exacerbated the situation and many of the urbanized areas have been affected and are still facing acute water shortages (Chan 1998 and 2000).
Treating water contaminated with substituted aromatics using a kenaf-based biosorptive process
Year: Authors: Zappi M., Subramani A., Ekanayake G.
An innovative process is under development for treatment of contaminated waters. The process involves adsorption of contaminants onto plant materials, kenaf, that are loaded within a packed column. After the sorptive capacity of the kenaf is expended, then the spent kenaf fibers will be disposed of using composting. The composting step will not only reduce fiber volume, but this step will also biologically degrade the phenol adsorbed onto the fibers. This process is viewed as a direct competitor to activated carbon, which is one of the most common treatment processes, used for wastewater and groundwater remediation. Results indicate that kenaf has a much lower adsorptive capacity for DCP then activated carbon. However, kenaf had a similar adsorptive capacity, compared to activated carbon, for TNT. In the case of DCP, the adsorption isotherm slope factor is steeper for the kenaf than the activated carbon indicating that the loading capacity of the kenaf as an adsorbent is much more sensitive to changes in targeted eMuentlevels than activatedcarbon. However, the adsorptive characteristics ofkenaf toward TNT were almost identical to that of activated carbon in terms of all model parameters. Stabi/ity testing of kenaf within a packed column undergoing continual and intermittent hydraulic loading indicated that kenaf is surprisingly stable within a dynamic column setting. Finally, composting of kenaf appears feasible using thermophiles
Aerial hyperspectral remote sensing for wetland eelineation and water resource impacts by transportation infrastructures
Year: Authors: Wasson L., King R., Shaw D.
Aerial Remote Sensing has proven to be an efficient and effective tool in gathering surface information of large-scale surveys. This past summer Mississippi State University’s Remote Sensing Technologies Center (RSTC) embraced the challenge of mission planning and operation of an aerial hyperspectral remote sensing platform for agricultural and environmental research. A hyperspectral imager collects large quantities of spectral data over several hundred wavelengths in the electromagnetic spectrum. RSTC, in conjunction with NASA, TRW, the Mississippi Space Commerce Initiative and GEOTEK Aerial Management Services conducted an aerial hyperspectral imagery campaign during the summer and fall of 2000 using the TRWIS III hyperspectral imager. MSU is also the local institution for the National Consortium on Remote Sensing in Transportation - Enviornmental Assessment (NCRST-E). Planning of transportation systems encompasses an environmental review process mandated to comply with the National Environmental Protection Agency (NEPA). The need to develop an adequate baseline of information on existing environmental conditions is an expensive and time-consuming process in transportation planning. Of particular interest to the consortium and RSTC is wetlands delineation for the Department of Transportation (DOT). With aerial hyperspectral imagery, plant species common to wetlands are detected at resolutions required by DOT. Use of this technology will greatly reduce the time meeting NEPA guidelines. Presentation of research will include imagery of transportation infrastructures along Mississippi’s coastal environment. Hyperspectral flights have been flown over the I-10 corridor along Mississippi’s gulf coast with the aim of observing impacts of transportation on coastal environments.
Development of a total maximum daily load (TMDL) for total near Iuka, Mississippi biochemical oxygen demand (TBODU) for Indian Creek
Year: Authors: Sheely L.H.
The identification of waterbodies not meeting their designated use and the development of total maximum daily loads (TMDLs) for those waterbodies are required by Section 303(d) of the Clean Water Act and the Environmental Protection Agency’s Water Quality Planning and Management Regulations. The Mississippi Department of Environmental Quality (MDEQ) has identified a segment of Indian Creek as being impaired for a total length of 3 miles as reported in the Mississippi 1998 Section 303(d) List of Waterbodies. This segment is located in northeastern Mississippi within the Tennessee River Basin: beginning at the luka POTW outfall and ending at the confluence of Pickens Branch, Figure 1. The pollutant of concern in Indian Creek is enrichment of organic matter, which causes low instream levels of dissolved oxygen (DO). Oxidizable organic matter is measured in terms of total ultimate biochemical oxygen demand (TBODU). TBODu is the oxygen consumed by microorganisms while stabilizing carbonaceous and nitrogenous compounds under aerobic conditions over an extended time period. TBODu is equal to the sum of carbonaceous biochemical oxygen demand (CBODU) and nitrogenous biochemical oxygen demand (NBOD"). The TMDL process is designed to restore and maintain the quality of impaired waterbodies through the establishment of pollutant specific allowable loads. The TMDL for Indian Creek is the maximum allowable load of TBODu that can be placed in the waterbody, while allowing the waterbody to maintain state water quality standards. The allowable load of TBOD" for Indian Creek was developed based on the state standard for DO as defined in the State of Mississippi Water Quality Criteria for Intrastate, Interstate, and Coastal Wafers (MDEQ 1995b). The state standard specifies that for waters designated for use as fish and wildlife support, the DO concentration shall be maintained at a daily average of not less than 5.0 mgll with an instantaneous minimum of not less than 4.0 mgll. In order to adequately protect the designated use of Indian Creek, these standards must be attained under low-flow, critical conditions. MDEQ Regulations define "low-flow, critical conditions" as the 7Q10 flow and temperatures of 26°C in the summer (May - October) and 20°C in the winter (November - April). The 7Q10 flow is the minimum flow expected for seven consecutive days during a time period of ten years. A water quality model, QUALZE. was selected to determine the assimilative capacity of the creek for the pollutant of concern under critical conditions. The QUAL2E model includes both point and nonpoint sources of TBODU. One point source of TBODu is located within the modeled segment of Indian Creek, the luka POTW facility, a two- cell conventional lagoon with a chlorine contact chamber. Discharge monitoring reports (DMRs) and effluent samples collected in September 1998, during a study of Indian Creek, were used to characterize the facility’s effluent. DMRs indicate that this facility is currently operating within the limits for 5-day biochemical oxygen demand (BODs) loading set within its NPDES permit. Nonpoint sources of TBODu were quantified by measuring the background concentration in the headwaters of the creek.
Use of a commercial surfactant for enhanced biodegradation of organic wood-preservative contaminated processwater
Year: Authors: Shiohara K., Diehl S.V., Borazjani A.
A commercial surfactant (Brij 35) was studied in combination with and without a bacterial species known to break down pentachlorophenol (PCP) and polycyclic aromatic hydrocarbons (PAHs) associated with creosote. The effects of the surfactant, the bacterium, and the combination of the surfactant and bacterium, were evaluated in the biodegradation of process water highly contaminated with PAHs and PCP. Studies were conducted with 900 ml of process water in 1 liter amber jars. Nutrients along with the surfactant andlor bacterium were added to each jar and aeration was applied throughout the period of the study with an air sparger. Unconditioned controls and sterilized controls were also run. Samples were collected, extracted, and analyzed at 30 days and 60 days for PAHs and PCP, and also at day 90 for further PCP analysis. Total selected PAHs were significantly reduced in the surfactant and surfactant amended bacterial treatments. The results for PCP varied showing an increase during the study.
Construction of 2,4, & Trinitrotoluene- and nitrobenzene-catabolizing bacilli by transformation and gene fusion with plasmid
Year: Authors: Yang W.H., Yang J.R.
Nitroaromatic compounds are used in large quantity for production of plastics, explosives, pharmaceuticals, and pesticides (Bryant and DeLuca. 1991; Hallas and Alexander, 1983; Kedderis et al.. 1988; Nishino and Spain, 1993). As a result. large amount of nitrobenzene is contaminating the environment at a rate of tens of millions of pounds annually (U.S. Environmental Protection Agency, 1978). In addition, nitrated polycyclic aromatic hydrocarbons are also formed during a variety of combustion processes causing serious environmental pollution (Rafii. et al.. 1991). Reduction of the nrtrogroup is a common first step in the biotransformation of nitroaromatic compounds either leading to mineraliation of the compounds (Groenwegen et al., 1992: Nishino and Spain, 1933) or leading to accumulation of dead-end products, many of @em are cytotoxk or mutagenic (Bryant C. and McFlory. 1991; McCoy et al., 1990; Tatsumi et al.. 1982; Narai, N., S. Kitamura. and K. Tasumi. 1984). Aerobic degradation of ammatic hydrocarbons by a microorganism was first demonstrated in the early 1900s.. Since then, various strains of bacteria and fungi capable of cataboliing aromatic hydrocarbons were isolated (Gibson et al. 1984). Biodegradation of aliphatic hydrocarbons (gasoline and diesel oil ) by bacteria were also developed contributing greatly in bioremediation of enviroment disaster by oil spill (Reisfeld et al. 1972; Rosenberg et al. 1979 a, b; Britton 1984; Shabtai et al. 1985; Yang et al. 1998a, b ). Study on the biotransfonnation of nitrated aromatics such as 2,4,&trinitrotoluene (TNT) and nitrobenzene by bacteria demonstrated’ either aerobic or anaerobic metabolic pathway for degradation (Crawford, 1995; Marvin-Sikkema. 1994; Michaels and Gottschalk. 1995; Preuss et al. 1993; Spain, 1995; Stahl and Aust 1995, Pasti- Grigsby et al., 1996). Reduction and release of nitro groups as nitrite was reported in aerobic microbial degradation of some nitroaromatics (McCormick et al. 1976). Our earlier report indicated that aliphatic hydrocarbon catabolism (Yang et al. 1996a. b). and aromatic hydrocarbon catabolism in bacilli bacteria (Yang et al. 1997) can be enhanced by transformation of bacilli with either plasmid pTV,Ts or pLTV, . The object of the current study is to investigate further whether the specific benzene- cataboliing capability of plasmids pTV,Ts or pLTV, (Yang et al. 1997) can enhance biodegradation of nitroaromatics in the transformed bacilli or not. Can the nitroaromatics-biodegradation capability of the transformed bacilli be enhanced by induction of denitrification catabolism with the inducer, sodium nitrate?
Double cropping berseem clover and grain sorghum for nutrient management of swine waste
Year: Authors: McLaughlin M.R., Fairbrother T.E., Rowe D.E.
The mission of the Waste Management and Forage Research Unit at Mississippi State centers on developing forage crops in management systems, which facilitate safe, sustained application of animal waste on agricultural lands in the South. Adapted summer and winter forage crops are tested in 12-month production systems for their abilities to capture and mine potentially polluting nutrients, especially nitrogen and phosphorus, derived from animal waste. The nutrients are removed as economically valuable hay, which may be used for animal feed at other locations. The utility of different management systems and forage species is determined for different soils and types of animal waste. Forage species are selected for persistence, dependability, and productivity in heavily manured fields. Economically reasonable management alternatives are tested for improvement in rates of nutrient removal. The goal of this research is development ofguidelines, systems, and forages for sustained and safe use of fields for waste disposal. A 12-month double cropping system, comprised of winter annual berseem clover, Trifoliurn alexandrinum L.. and summer grain sorghum, Sorghum bicolor (L.) Moench, was tested for nutrient management in a black prairie field soil. The field was under heavy fertilization with swine lagoon effluent and was located on a privately owned hog farm in southwestern Lowndes County, Mississippi. Partial results from the first 2 years of an ongoing study, begun in October 1997, are reported here. The effects of bean yellow mosaic potyvirus (BYMV) infection in the berseem clover were also examined (McLaughlin and Fairbrother 1996).
Fish movements between the Mississippi River and an oxbow lake, Arkansas-Mississippi
Year: Authors: Schorr M.S., Miranda L.E.
Fish production in floodplain river ecosystems is significantly influenced by the duration and magnitude of flooding events (Welcomme 1976, 1979, 1986; Goulding 1980). Oxbow lakes and other backwater areas, if accessible, are utilized by many nverine fish species for spawning and foraging during high-water periods (Sparks 1995). Unfortunately. levee construction has reduced the floodplain area of the Lower Mississippi River by more than 90% (Sheehan and Rasmussen 1993). In the "Delta" region of Mississippi, oxbow lakes of the Mississippi River support commercial and recreational fisheries (Lucas and King 1986). However, many of these lakes are excluded from the floodplain by levees, and thus have no seasonal interactions with the river. In contrast, oxbow lakes located on the river-side of the levees (in the floodplain) establish connections with the main channel (every year or less often), and thus are influenced by river-lake exchanges of water, nutrients, and fishes. Fish populations in these oxbows may be regulated more by river-lake fish exchanges than by angler harvests. However, there is relatively little published information on the nature and extent of river-lake fish movements in floodplain river ecosystems, particularly in the Lower Mississippi River. Our study was designed to assess seasonal fish movements through a floodplain canal connecting an oxbow lake to the Mississippi River. We characterized the fish stocks using the canal during the high-water period in the winter-spring, and described the direction of fish movements (toward the river or lake) in the canal.
Concentrations of selected pesticides in treated and untreated drinking water from Lake Bruin, Louisiana, April - December 1999
Year: Authors: Manning M.A.
Contamination of surface water in the United States from pesticide application has been a major waterquality issue during the past several decades. Nationwide use of pesticides increased more than 300 percent from 1968 to 1988. A total of 4.6 billion pounds of pesticides was applied in the United States during 1997 (U.S. Environmental Protection Agency, 2000). It is always of concern that a percentage of applied pesticides could move from the site of application and subsequently contaminate local surface waters. Even a small amount of pesticides in surface waters may represent a threat to the aquatic ecosystem and to human health. Because lakes and reservoirs store water and do not have the flush effect of rivers and streams, pesticide concentrations in lakes can have a much longer residence time. Therefore, agricultural compounds dissolved in lakes with long residence times may occur at lower concentration value due to dilution, but can persist longer in the water column because of storage (Stamer. Battaglin. and Goolsby 1998). The purpose of this study was to determine the occurrence of a broad range of pesticides in reservoirs that supply a source of drinking water to the public. Data collected during this study expands the National Water Quality Assessment Program (NAWQA) extensive pesticide database to include surface waters used for drinking water. From April to December 1999, the U.S. Geological Survey (USGS), National Water Quality Assessment Program in cooperation with the U.S. Environmental Protection Agency, Office of Pesticide Programs (EPA-OPP), conducted a pilot study to monitor the concentration of selected pesticides in lakes that supply water for public consumption. Lake Bruin, located in an intensive agricultural region of northwestern Louisiana, was selected as one of several lakes throughout the Nation to be monitored.
Water-Quality Monitoring and Data Collection in the Mississippi Sound
Year: Authors: Runner M.S., Floyd T.
The Mississippi Department of Marine Resources (MDMR) and the U.S. Geological Survey (USGS) are collecting data on the quality of water in the Mississippi Sound of the Gulf of Mexico in support of the MDMR missions to protect the public health from diseases associated with the consumption of raw shellfish and to assist in the management of shellfish and their habitats as renewable resources. Data are being collected in the Mississippi Sound of the Gulf of Mexico as well as in its estuaries. This report describes data-collection efforts of the MDMR and USGS in the Mississippi Sound. Included in the report are (1) type of data collected, (2) methods of data collection, (3) description of data-collection sites, and (4) preliminary results of data collected for instrument verification. Data are being collected on the quality of water in Mississippi Sound and its estuaries. The Mississippi Sound is the part of the Gulf of Mexico that lies between the Mississippi Coast and the barrier islands, and extends from the mouth of the Pearl River to the Mississippi-Alabama State boundary. Data collection consists of the collection of discrete water samples for laboratory analysis and the operation of in situ water-quality monitors for the recording of continuous data. The MDMR collects discrete water samples at 169 locations. The USGS operates continuous water-quality monitors and collects water samples at five locations in the coastal region.
Trace element concentration in bed sediment in the Mississippi embayment study unit
Year: Authors: Wates M.L., Kleiss B.A.
In 1991. the U.S. Geological Survey (USGS) began the National Water-Quality Assessment (NAWQA) Program to describe current water- quality conditions in a large part of the nation’s streams, rivers, and aquifers. The purpose of the NAWQA program is to characterize current water- quality conditions, to observe any changes in water-quality over time, and to improve the understanding of natural and anthropogenic factors that influence water-quality. The study incorporates more than 50 of the nation’s largest river basins and aquifer systems; one of these basins is the Mississippi Embayment (MISE) study unit. In 1995, as a part of the MlSE study unit evaluation, the USGS collected bed sediment from 15 sites that (fig.1) represented a variety of land use and streams throughout the study unit. More than 85 percent (median value) of the land in the MlSE study unit is used for agriculture and includes row crops, grain crops, pasturelhay, and other grasses. The remaining land is used for forestry, wetlands, or open water. The sampling of bed sediment is important because changes in the chemistry of bed sediment can provide insight about the environment surrounding the stream. In addition, it is important to understand the concentrations of potential toxins in sediment that could be available to biotic communities, possibly causing environmental effects. Bed sediment samples were analyzed to determine the concentrations of 34 trace elements, nine of which were chosen to discuss in this report. These nine, aluminum, arsenic, cadmium, chromium, lead, mercury, nickel, selenium, and zinc, were chosen because, as some of EPAs Priority Pollutant’s, they are considered a threat to aquatic organisms and human health (Rice 1999). The objectives of this paper are to present trace element data from 15 sites and to compare MlSE concentrations to national medians and applicable guidelines.
Application of pelletized poultry manure at time of planting
Year: Authors: Bush P.B., Merka W.C., Morris L.A.
Field studies conducted in the Georgia Coastal Plain indicate that palletized chicken litter applied at a 1 dry ton/acre rate (26.5 lb/acre P) can serve as a good P source for pine stand establishment. Pine seeding mortality was observed on a poorly drained, wet site associated with higher (3 ton/acre) treatment rates, perhaps because anaerobic conditions may lead to excessive ammonia build-up. Greenhouse studies indicated that poultry manure-primary paper pulp sludge mixtures have potential value as a slow-release nutrient source, but fresh mixtures of the two materials retain some of the adverse properties that lead to poor seedling survival in soils amended with fresh poultry manure. Pine survival and growth is improved by composting poultry-primary sludge mixtures before application. Over-application of fresh litter can result in excessive NO3-N leaching below the root zone to groundwater. Economic analysis indicated that pelletized chicken litter applied at a 1 ton/acre rate would cost $24.10/acre. This compares favorably with the current DAP application cost of $30.00/acre. Weed control measures currently used in intensive stand management would minimize the potential increase in week populations from litter applications. Limitations on the use of poultry litter include 1) the limited number of acres that can receive applications per day due to time considerations for hauling and handling, 2) the difficulty of operating traditional spreader trucks on uneven and poorly prepared sites, and 3) the convenience of procurement and aerial application of DAP, which may offset cost savings of using poultry litter. However, poultry litter can be used as an alternative to industrial-standard fertilization when: 1) transportation distances are small, 2) it can be applied during site preparation, and 3) accommodations for equipment access to the stand are not excessive.
Bacteriological evaluation of water quality in the Ross Barnett Reservoir in Mississippi
Year: Authors: Tchounwou P.B., Warren M.
Ross Barnett Reservoir (RBR) serves as a source of water supply for the city of Jackson, Mississippi, by sustaining flow in the Pearl River during dry periods. It also constitutes an important site for recreational activities for many of the Hinds, Madison, and Rankin counties’ residents. A broad spectrum of illnesses have been associated with water-contact activities such as bathing, swimming, boating, and fishing in marine and fresh recreational waters. In this research, we assessed the bacteriological quality of water in the RBR and compared the bacteria levels to the recommended criteria for public health protection. During the summer of 1999 (from 06/12/99 to 10/02/99), weekly water samples were collected aseptically from two different sites on the reservoir and assessed for a number of bacteriological parameters including: heterotrophic plate counts (HPC), total coliforms (TC), fecal coliforms (FC), and fecal streptococcus (FS), following membrane filtration techniques (MFT), as described in "Standard Methods." During sampling, in sifu measurements of other basic physico-chemical characteristics of water such as conductivity, dissolved oxygen (DO), pH, temperature, and total dissolved solids (TDS) were also performed. Bacterialdensitiesof95.3x105f 74.2~10~. 13.4~10~ f 31.4x104, 8 . 5 ~ 1 0 ~ f 9.3x102, and 6 . 8 ~ 1 0 ~ k 21.3~10~ coloniesforming units (CFU) per 100 mL ofwaterwere recorded from HPC, TC. FC. and FS, respectively. These bacterial levels exceeded the existing state and federal guidelines for indicator organisms in recreational waters, especially for TC, FC. and FS. The mean values of water conductivity and pH were 75.2 f 4.9 usec/cm and 8.0 f 0.5 pH units, respectively. The average DO concentration was 9.8 f 4.3 mglL, and that of TDS was 34.9 t 2.4 mg/L. The mean temperature was 32.0 f 23°C. No significant correlation was found between bacterial (HPC. TC, FC. and FS) densities and the other environmental parameters. Although the physical and chemical parameters were at acceptable levels throughout the summer, bacterial levels often varied by several orders of magnitude. Such levels of bacteria in the RBR have implications for the public health and should be given a serious consideration.
Factors affecting phosphorus runoff from pastures
Year: Authors: DeLaune P.B., Moore, Jr. P.A., Daniel T.C.
Non-point source phosphorus (P) runoff from pastures fertilized with animal manures can lead to accelerated eutrophication in lakes and streams. Animal manures tend to have a low N:P ratio and are applied based on nitrogen needs, hence P application is excessive. In pasture systems, manure is generally applied without incorporation, leading to increased levels of P near the soil surface. Continual application of animal manures for several years increases the soil P levels and leads to the threat of losses in surface runoff (Pote et al., 1996). Edwards and Daniel (1993b) have shown that poultry litter applications to pastures result in relatively high P runoff at recommended rates with as much as 90% of the P runoff being in the soluble form. Soluble reactive P is very important due to its direct bioavailability to aquatic plants, whereas particulate P must undergo conversion to inorganic phosphate before becoming bioavailable (Sonzongi et al., 1982). Because P is normally the limiting nutrient for eutrophication, concerns have arisen over animal waste applications (Schindler. 1977). Sharpley et al. (1993) stressed the importance of emphasizing management practices based on soil P rather than N, particularly for soils susceptible to P runoff. Several researchers have studied the relationship between soil test P and soluble reactive P (SRP) concentrations in runoff. This positive relationship has been observed concluding that the P content of surface soil directly influences the amount of SRP in runoff from that soil (Schreiber et al., 1988; Sharpley et al.. 1994, 1995; Pote et al., 1996, 1999). As a result, several states are attempting to determine threshold soil test P levels above which animal manures may not be applied due to increased risk of P runoff. Perhaps more importantly, is the level of SRP that is applied in animal manures, which is highly susceptible to surface runoff. Sauer et al. (2000) suggested that for plots treated with poultry litter, the main factor affecting P concentrations in runoff is the SRP present in the litter on the soil surface. Several other studies have also shown that SRP concentrations in runoff are higher when runoff events occur after manure is applied to the soil surface (Edwards and Daniel, 1993b; Shreve et a1.,1995; Sharpley, 1997). In these studies, rainfall was applied 1 day after litter application to small plots. Several management scenarios are available to reduce the risk of P runoff. Aluminum sulfate (alum) additions to poultry litter have been shown to reduce SRP concentrations in both litter and runoff (Moore and Miller, 1994; Shreve et al.. 1995: Moore et al., 2000). Shreve et al. (1995) reported that alum-treated litter resulted in an 87% reduction in SRP runoff concentrations compared to untreated litter. The addition of phytase enzymes to poultry and swine diets have also been shown to decrease inorganic P levels in the manure (Nelson et al.,1971; Jongbloed and Kemme. 1990; Beers and Jongbloed. 1992). The use of a low phytate corn variety (Rayboy et al., 1994) has also been used to reduce P levels in manures (HAP, high available P corn). However, Moore et al. (1998) found no statistically significant reduction in P runoff from plots receiving dietary manipulated poultry litter, although HAP corn and HAP/phytase litter lowered P runoff by 22 and 26%, respectively. The timing and frequency of rainfall events have also been shown to effect the quality of runoff water (Westerman and Overcash, 1980; Edwards and Daniel, 1993b; Sharpley, 1997). Sharpley (1997) and Westerman and Overcash (1980) observed a decrease in P runoff with an increase in the length of time between applying manure and a surface runoff event. However, studies conducted on swine manure by Edwards and Daniel (1993a) found little effect on P runoff with time (up to 14 days). Several different studies have observed various factors affecting P runoff. However, no studies have combined these factors and compared the effect each has on P runoff. The objective of this study was to determine the effects of 1) soil test P; 2) poultry litter application rates; 3) dietary manipulated litter; 4) alum-treated litter; 5) fertilizer type; and 6) weather on P runoff.
Phosphorus Partitioning Among Plant Parts of Forages Fertilized with Poultry Litter or Swine Effluent
Year: Authors: Pederson G.A., Brink G.E.
Poultry litter and swine effluent are often used as fertilizers on forages grown in the southeastern U.S. Application rates of animal waste of forages usually are based on the nitrogen requirement of the plants. However, poultry litter or swine effluent applied to meet the plant’s nitrogen requirement contain more phosphorus than is required by the plant and P buildup in the soil will occur (Kingery et al. 1993; Sharpley, Gburck, and Heathwaite 1998; Smith et al. 1998). This excess P may be lost via surface runoff, erosion, or leaching (Smith et al. 1998). Harvesting of forages as hay is one management technique that will help remove excess P from poultry litter- or swine effluent-fertilized soils. Proper management of forages is essential to maximize P uptake from hayfields fertilized with poultry litter or swine effluent. Traditionally, producers have managed hay fields for maximum yields of high-quality forage (Albrecht and Hall 1995). To achieve high quality forage, plants are often harvested prior to full maturity when leaves comprise a greater proportion of the hay. Higher yields can be obtained by letting the plants reach full maturity, however forage quality decreases (Ball, Hoveland, and Lacefield 1991). To maximize P uptake and removal via hay, plants should be harvested at full maturity. Nutrient uptake is based on both the concentration of nutrient within the forage and the total dry matter yield of that forage. When nutrient uptake becomes the main goal of a hay production system, forage quality is of less importance than maximizing dry matter yield. Producers affect nutrient uptake by altering management techniques such as animal waste application rates, application time, or plant maturity at harvest. To select the proper management techniques, producers must first know where within the plant P is located. Then forages can be managed to optimize growth and yield of that particular plant part. In this paper, results are presented from three studies showing phosphorus distribution within plant parts of annual and perennial legumes, annual grasses, and Bermuda grass.
Combining grazing and hay production for femediating soil P in pastureland of the Southeast U.S.
Year: Authors: Aiken G.E., Edwards J.H., Pote D.H.
Confinement poultry and hog production are concentrated in the southeastern U.S.A., where most of the soils are marginal for crop production. Because much of the agricultural land is utilized for forage production, confinement animal production in the region is often combined with cattle grazing to diversify production and make use of poultry waste as a low-cost fertilizer for pastures. Application of 4.5 to 9 metric tons of broiler litter peer ha effectively promotes grass growth (Hileman, 1967, 1973). Huneycutt el al. (1988) showed that litter applications of 13 Mg ha-1 increased dry matter yields of tall fescue (Festuca arundinacea L.) and Bermuda grass (Cynodon dactylon [L.] Pers.) by 306 and 215%, respectively. Animal waste therefore can be effectively utilized as a fertilizer source for boosting the growth of forages. A problem with using animal waste as a fertilizer is that phosphorus (P) is often applied in quantities that are above plant requirements. Consequently, P can accumulate and increase concentrations of soluble phosphorous in runoff and cause eutrophication of surface waters (Sharpley et al., 1994). A direct linear relationship between runoff phosphorus and Mehlich-3 phosphorus has been observed (Pote et al., 1996). There apparently is potential for developing environmentally unsafe P levels in runoff as soil phosphorus increases. Pastures and hay meadows with excessive soil P will require remediation through the development of forage systems that provide maximum growth distribution of productive forage species. Managing both cool- and warm-season grasses can maximize the annual distribution of growth and uptake of P in aboveground forage. Furthermore, the wide distribution of annual forage growth must be intensively utilized in a manner that results in movement of the accumulated P in forage growth out of the pasture or hay meadow for eventual transfer to lower-P soils. Animal waste is often applied to Bermuda grass and Bahia grass pastures and hay meadows because the two warm-season perennial grasses can effectively utilize the high nutrient concentrations of animal waste. Cool-season annual grasses (rye [Secale cereale L.], wheat [Triticum aestivum L.], or ryegrass [Lolium multiflorum L.]) can be notill planted into Bermuda grass and Bahia grass to provide growth during dormancy of the two warm-season grasses (Ball et al., 1996). Although cool-season grasses increase the annual distribution of growth, hay production with these grasses is difficult because cool, moist weather conditions during most of the season prevent sufficient drying of hay. Production of silage or haylage is an option for utilizing cool-season herbage, but requires special equipment, long storage times increase spoilage, and the bulkiness of silage and haylage makes transporting difficult (Rotz and Muck, 1994). This option is most feasible for fields with severely high soil-P levels, requiring expeditious remediation of soil P. It is also possible to graze cool-season grasses to take advantage of the forage production and remove small quantities of P. Cattle grazing may be necessary for some farms because cattle production is the main source of income and available land is limited. The objective of the paper is to discuss forage systems that are developed for remediating soil P and combine intensive production of hay during the warm-season with cattle grazing during the cool season.
The MSEA and stride educational collaboration
Year: Authors: Thibaudeau G., Beamon H., Pote J., Harpole S., Bailey J.
With her rich soil, the Mississippi Delta is home to some of the most productive farmland in the world. Student and Teacher Research Institute - the Delta Experience (STRIDE) is a project that works in cooperation with the Mississippi Delta Management Systems Evaluation Area Project (MSEA) to involve, on a yearly basis, more than 20 Delta middle school students in environmental research in the Mississippi Delta. The project described herein offers an opportunity for ten groups of students, partnered with middle school science teachers, to connect science, engineering, technology, and agriculture while developing skills needed to prepare for future educational experiences. These research experiences enhance the teacherktudent teams’ knowledge in scientific methodology through participation in current MSEA projects. Such projects have been designed to study the agricultural effects on water resources and ecological processes at three Mississippi Delta oxbow lake sites. Research experiences provide students with skills they need to compete in today’s job market. Industry leaders consistently state that skills needed by their workforce include communication, creative problem solving, working in collaboration, decision-making, mathematical skills and computer skills. Involving teachers and students in research provides teachers with experiences that they subsequently transfer to the classroom and enhances students’ opportunity to develop the necessary skills. The primary objective of STRIDE is to train teachers and students of upper middle schools in the Mississippi Delta in research data collection and analysis techniques through scientific research experiences. Through their experiences, teachers understand the role of research in the classroom and enhance their scientific content knowledge. Students receive meaningful interdisciplinary research experience and learn how to design and evaluate best management practices for improving water quality and ecology in the Mississippi Delta. Participants increase awareness of Onvironmental a v i management issues relating to the Mississippi Delta rivers and lakes. STRIDE participants also increase their awareness of careers in science and engineering. MSEA is part of a consortium of Federal, State, and local agencies involved in promoting good water practices. The MSENSTRIDE collaboration provides an excellent opportunity for students to experience research that is important to the environment and economy of the Mississippi Delta. The collaboration also meets a primary goal of MSEA, providing education, research, and community sewice in issues of water and associated land-use problems, assuring that a valuable resource will be available to future generations. The project focuses on three watersheds located in west central Mississippi in the Delta counties of Sunflower and Leflore. each utilizing a different farming management practice. The three practices are structural and cultural best management practices (BMPs). only structural practices, and no BMPs initially. The four major objectives of MSEA are: (1) to develop alternative farming systems for improved water quality and ecology in the Mississippi Delta rivers and lakes; (2) to increase knowledge of the design and evaluation of economical environmentally-sound BMPs as components of farming systems; (3) to assess the effects of agricultural activities on surface and shallow ground-water quality; and, (4) to increase awareness by farmers and landowners of alternative farming systems to reduce adverse agricultural effects on water resources and ecological processes. Teachers and students participate in research projects being conducted by scientists who are employed by the various agencies and institutions associated with the MSEA project. This paper describes STRIDE as a cooperative effort between the Mississippi Delta Management Systems Evaluation Area project and Mississippi State University, funded in part by the National Science Foundation. Student and teacher teams work with MSEA scientists in the field and/or laboratory on projects already in progress. These teams assist with various aspects of research including collecting, recording, and analyzing data.
Telemetric applications for hydrologic data in Mississippi
Year: Authors: Wallace S.
The US. Geological Survey in Mississippi uses a variety of telemetry equipment such as Global Positioning Systems (GPSs), landline and cell phone modems, radio bridges, satellite transmitters, and WWV receivers. Implementation of telemetric technology helps provide timely, accurate, and reliable hydraulic and hydrologic data to water- resource managers throughout the state. Global Positioning Systems aid in determining the exact location of points of data collection. Recently, GPSs are being used for bottom tracking correction for Acoustic Doppler Current Profilers. Phone modems, used in conjunction with conventional telephone lines, are an important part of local alert systems. They allow system users to query instruments 24 hours a day, and provide remote reprogramming and troubleshooting capabilities. The advent of cellular technology allows use of phone modems in areas where there are no phone lines. Recent software developments make it possible to access a data-collection site from personal or laptop computers and Fne tune instruments in a fully interactive environment. Radio bridges link remote sensors to data loggers at sites where there are multiple sensors or at sites whereconditions are unfavorable to locate weather- sensitive equipment. Satellite transmitters provide high-quality, low maintenance data transmissions across the National Oceanographic and Aeronautics Administration Geostationary Operational Environmental Satellites, and are the backbone of the USGS real-time data collection system in Mississippi. W receivers use atomic time data transmitted via Federal Communications Commission radio station W by the National Institute of Standards and Technology to automatically calibrate field equipment. The receivers help to eliminate clock drift problems, thus reducing field maintenance costs.
Applications of high frequency ultrasound for water disinfection
Year: Authors: Chamul R.S., Silva J.L.
Recently there has been a trend in the search for new technologies that will inactivate microorganisms without the use of heat or the use of chemical additives. One technology with potential is high frequency ultrasound (HFU). It is used to kill microorganisms in liquid systems by the principle of cavitation. At high frequencies, cavitation causes smaller bubbles with higher energy. When these bubbles collapse, very high temperatures at these microenvironments result. This leads to ionization effects and formation of radicals. The objectives of this project were to study the effect of different intensities of high frequency ultrasound to disinfect water in order to reduce the chances of waterborne pathogens being present. To do this, evaluation of the quality of groundwater in an aquifer in northeast Mississippi was studied, and the effect of HFU on microbial load of this water was conducted. Groundwater used for this treatment from an aquifer in northeast Mississippi was sampled to evaluate its physical-chemical and microbial quality. It was found that this water varied in quality with season, probably due to rainfall and other environmental pressures. Three different types of HFU resistant bacteria were isolated from the water (Flavobacferium, Acinetobacfer baumannii, and Enferobacter cloacae) and used to evaluate the effect of HFU. Column of water and amplitude that produced maximum cavitation were chosen using an ultrasound generator K80 with a frequency of 850 kHz. Continuous ultrasound was used to calculate destructive values for Flavobacferium and Acinetobacter baumannii. Enterobacter cloacae was used for the pulsed experiment since it survived the continuous process. Continuous high frequency ultrasound has a better chance to be used to disinfect water than pulsed ultrasound because the conditions to produce cavitation are not ideal in the water and ultrasound per se is not able to accomplish any disinfection. Another possibility is to use HFU in conjunction with low levels of disinfectants to increase efficiency and guarantee total kill. Possible applications of this technology are in groundwater disinfection, food processing water and wastewater treatment, and recirculation of processing water.
Cracking Modes of an Expansive Mississippi Delta Soil
Year: Authors: Wells R.R., Prasad S.N., Romkens M.M.
Modes of crackin in expansive soils of the Mississippi delta and their impact on infiltration were examined. Preliminary laboratory infiltration studies suggested an evolutionary pattern of the crack formation and their impact on infiltration. Of particular importance in the evolution of the crack morphology, the role of the seal and development of stress within the substrate is discussed. Understanding the developmental aspects of cracked soils permits further development of infiltration relationships that are used to determine the transport capabilities of cracked soils.
Plant diseases as potential limited factors for forage production on animal waste disposal sites
Year: Authors: Pratt R.G.
INTRODUCTION A major problem in production of large numbers of swine, poultry, or cattle in concentrated facilities is the disposal, without pollution of the environment, of large quantities of waste products that are generated daily. The principal polluting substances present at high levels in animal waste products are compounds of nitrogen and phosphorus. The primary environmental effects of these pollutants, which are also major plant nutrients, are the induction of toxic nitrate levels in ground water used for drinking, and over-fertilization of lakes, rivers, and estuaries that leads to their rapid eutrophication and ecological deterioration (Sharpley et al. 1998). Current methods for disposal of excess nutrients from concentrated animal production facilities in the southeastern USA, which are intended to avoid environmental pollution, usually are based upon their application to forage crops as fertilizers. Nitrogen and phosphorus from animal wastes are absorbed by forages during their growth and removed from application sites during harvest of hay. This type of biological nutrient disposal system requires production of maximal quantities of forage on waste disposal sites in order to achieve maximal nutrient removal. Therefore, any factors that reduce yields of forage and hay crops on animal waste disposal sites, or prevent effectivegrowth responses of forages to applied nutrients, must be regarded as potential limiting factors for the successful use of forage-based nutrient disposal systems. During the past two years, symptoms of disease have been observed on bermudagrass and other forage species on swine and poultry waste application sites. In some instances, diseases were present at low frequencies in stands and did not appear likely to have caused significant yield reductions or other losses. In other situations where symptoms were more severe, diseases appeared to be significant factors that may have reduced yields in portions of stands and cauFzd major shifts in forage species compositicn. This paper presents a summary and overview of previous studies of plant diseases and pathogens on swine application sites; results of these studies will be described in greater detail in the near future (Pratt 2000). It also presents preliminary results of similar studies on poultry waste sites, and studies that involve sampling times and host ranges of pathogens. These results also are intended to be described in greater detail in later reports.
Establishing Herbaceous Wetland Plants on a WRP Site
Year: Authors: Grabowski J., Rodrigue P.
The objective is to evaluate the potential for using herbaceous wetland plants on a Wetland Reserve Program (WRP) site and to determine the appropriate planting area on the site that will provide the required water regime for each species planted. Two WRP properties located in Quitman County, MS were selected. Four planting sites were selected on the two properties. Sites were surveyed to determine area from one foot below (WL-1.0’) to one foot above (WL+1.0’) winter water level with each 0.5 foot increment marked (Figure 1). Each surveyed area was divided into three equidistant sections to determine planting row locations between the 0.5 foot elevation markers. Rows of plants were located parallel to the waterline on each elevation measurement and division totaling thirteen rows. Three plants of each species were planted on each row.
The Minnesota Manure Testing Laboratory Certification Program
Year: Authors: Jarman J.
The Minnesota Manure Testing Laboratory Certification Program began in 1996, with the objective of ensuring accurate and credible manure test results for livestock producers. Because no other laboratory proficiency testing programs for manure areavailable in the U.S., Minnesota sought to develop the program on a regional basis and allow participation of agricultural laboratories outside the state. Because of this, and because of testing industry needs in this area, participation in the program has grown from 14 laboratories in 1996 to an expected 35 to 40 laboratories in 2000. Participating laboratories do business in 15 states and 3 Canadian provinces, and the program is now operating on a national level. Any laboratory is welcome to participate, regardless ofwhere they do business. The goals of the Manure Testing Laboratory Certification Program include standardization of manure analysis methods, provision of proficiency testing and technical assistance services to agricultural laboratories, promotion of the use of manure testing by livestock producers and use of test results in proper nutrient management planning. Addressing these needs is important because of the increasing number of feedlots needing to fulfill regulatory requirements for development and implementation of manure management plans. Laboratories participating in the program are required to analyze 8 manure check samples per year for dry matter, total nitrogen, ammonium-nitrogen, phosphorus and potassium. Control limits are calculated for analysis results and labs are certified based on the percentage of their results that fall within the control limits. A fee of $100 annually is charged for certification. In addition to proficiency testing and certification, the program provides technical assistance to laboratories for development and modification of manure analysis methods. Work is also being completed on a handbook of reference methods for manure sampling, sample handling, analysis, and reporting of test results. Laboratory analysis of check samples in the first 3 years of the program has shown that certified laboratories are doing an excellent job of producing accurate manure test results. These results have also emphasized the need for increased educational efforts in proper sampling procedures and interpretation and use of test results. With support from the testing industry, fertilizer dealers, Extension, and state and federal regulatory agencies, the Manure Testing Laboratory Certification Program can also help address these needs. Proficiency testing results from the past four years will be presented, as well as a discussion of the effects of laboratory variability on manure application rates.
Development of a water supply from the Tuscaloosa aquifer in Choctaw County, Mississippi
Year: Authors: Hoffman J.H., Hardin, Jr. D.L.
During the last several years there has been a dramatic increase in interest in the development and expansion of electric power generating plants in the state. In the summer of 1998, the state of Mississippi entered a new era in industrial development, with the issuance of permits by the Mississippi Department of Environmental Quality (MDEQ) Permit Board for the first lignite mine and associated power plant to operate in the state. Issuance of these permits was the culmination of several years of intensive work on the part of representatives of the companies developing the lignite mine and power plant and the staff at MDEQ. In 1995, representatives of Phillips Coal Co. contacted the MDEQ regarding the possibility of obtaining permits for the mining of lignite and construction of the 400 megawatt power plant in Choctaw County (Fig. 1). The power plant will produce electricity for the surrounding area through the Tennessee Valley Authority (TVA). The lignite mine will be operated by Mississippi Lignite Mining Company (MLMC) and the power plant will be operated by Choctaw Generation Limited Partnership (CGLP). While MLMC permits dealt mainly with mining laws and regulations, CGLP had several separate concerns. One of the most significant of these was finding an adequate water supply for cooling. The power plant is projected to require approximately 6 to 10 million gallons a day (MGD) to be used as make-up water in their closed-loop cooling system. In meetings with CGLP, the Oftice of Land and Water Resources (OLWR) staff evaluated the principal aquifers currently used in the area. In Choctaw County, all sources of public water supply are developed in sands of the Meridian- upper Wlcox. middle Wilcox and lower Wlcox aquifers (Fig. 2). Approximately 10 miles to the east in Oktibbeha County, the Gordo aquifer has long been utilized for public and industrial water supplies (Fig. 3). None of the Wlcox aquifers used in Choctaw County were deemed to have the capability of producing the volume of water necessary for the power plant. More than 1.0 MGD of water is currently produced from these aquifers in the county and most of the wells only produce between 100 and 350 gallons per minute (GPM). Additionally, because of the shallow depths at which these aquifers occur, available drawdown space could be limited for large withdrawals of ground water. Surface water was also evaluated as a potential source. The Big Black River was the nearest surface water source of any significant size. This reach of the Big Black is near the headwaters of the stream, with a very limited drainage area, and lacks sufficient flow during low water stages to reliably supply the required volume of water for the power plant. Therefore, some other source of water had to be considered. Several published reports by United States Geological Survey (USGS) personnel and subsurface studies conducted by the staff of OLWR showed that there was an excellent chance of developing large-capacity water supply wells in the Tuscaloosa and possibly the Lower Cretaceous aquifers in the area. At the site of the proposed power plant, the water from all of these aquifers were expected to be unsuitable for human consumption without treatment, primarily due to excessive concentrations of total dissolved solids (TDS) and chlorides (CI). Because water quality was not a major concern for CGLP, a decision was made to drill a test well to determine the feasibility of developing the water supply for the power plant from these deeper aquifers,
Swine Operations: Comparison of Biological Filter Media for Odor Control and Wastewater Treatment
Year: Authors: Jones J.M., Burcham T.N., Columbus E.P., Zappi M.E.
Odor is an increasing concern in many agricultural locations across the United States, in particular, odor generated by waste and wastewater from confined animal housing/feeding operations (CAFO’s). Perception of an odor is a psychological response to an odorant, the actual molecule or molecules that cause the neurological response. The olfactory receptors transmit sensations directly to the olfactory bulb of the cerebral cortex. This portion of the brain, formerly called the "smell brain", is part of the limbic system which is now known to be the center for basic emotional drives and motivation (Fox 1993). Increasing public concern associated with nuisance odor and potential environmental problems associated with untreated or partially treated wastewater from CAFO’s has relegated the legislatures of both Mississippi and North Carolina to place moratoriums on the expansion of the swine industry in their respective states (Hayes 1999). Odors from CAFO’s have been identified from three major sources: (1) building and facilities, (2) outside storage systems, and (3) land application of manure and wastewater (Nicolai et al. 1998). Modern swine production facilities in the Southeast United States utilize large fans to ventilate the housing systems. While these fans serve to regulate the interior environment of the house, they force large volumes of odorant laden air directly in the local atmosphere. VanDevender (1998), found a statistically significant relationship between distance from the facility and odor intensity. Depending on atmospheric conditions, his study found that odor from swine production facilities could be detected by humans up to 0.48 km (0.3 miles) down-wind. Odor from land application sites was detected at distances up to 0.8 km (0.5 miles) in the same study. Further, high loading rate and low labor requirements associated with flush-style waste removal has resulted in the widespread adoption of anaerobic lagoons for wastewater treatment in most confined livestock facilities. Anaerobic digestion of waste can release ammonia, hydrogen sulfide, and volatile fatty acids such as organic acids, alcohols, aldehydes, fixed gases, carbonyls, esters, amines, sulfides, mercaptans, and nitrogen heterocycles as a result of the biological treatment process. Subsequent land application of this wastewater can release these odorants into the air, thereby exacerbating odor complaints. Although there are known methods for odor reduction, no current technology has proven to be cost-effective on a commercial production scale. Accordingly, the goal remains to design a treatment system that reduces odor and biologically treats wastewater from organic waste streams in a cost-effective manner. This prompted the development of the Swine Odor Reduction Bioreactor System (SORBS).
Utilization of organic byproducts to reduce soil extractable P from repeated application of manures
Year: Authors: Edwards J.H., Norton L.D., Aiken G.E., Way T.R.
Loilg-term application of animal manures to agricultural land can result in build-up of soil P. As a result, states are limiting the quantity of animal manure or commercial fertilizer P that can be applied to agricultural land when soil extractable P exceeds predetermined limits. Alternative uses of animal manure are being developed in cases where land utilization will cause significant environmental risk. Products are being developed by mixing, blending, or co-composting organic wastes including waste paper to reduce volume or toovercomechemical problemsassociated with the byproduct or to overcome soil problems from repeated applications. We determined the effectiveness of blending different organic wastes to remediate soil with extractable soil P levels > 200 mg ha-’. One experiment included a series of forage systems as well as the soil amendments. A soil amendment was developed that blended waste paper with (NH,),SO, .The C:N ratio of the soil amendment was adjusted to 2O:l. All soil amendments were incorporated into the top 10 cm of soil (Zulch fine sandy loam). Initial soil samples were collected in the spring by horizon prior to amendment application to a depth of 90 cm. Soil samples were collected in the Ap horizon five months after application of organic soil amendments. Significant differences in Mehlich-3 soil extractable P were found only in the 0-6.5 and 6.5-15 cm soil depths. Using (NH,),SO, to adjust the C:N ratio was the most effective waste paper treatment to reduce soil extractable P. Water soluble P was significantly affected in both the 0- 6.5 and 6.5-1 5 soil zone by the application of waste paper blended with (NH,),SO,.
A study on microbial ecotoxity and mutagenicity of 1-aminopyrene and 1-hydroxypyrene
Year: Authors: Hwang H.M., Shi X., Ero I., Yu H., Dong S.
Polycyclic aromatic hydrocarbons (PAHs) enter natural environment from a variety of sources, such as forest fires, volcanic eruption, incomplete combustion of fuel and other materials, industrial effluents and seepage or spillage of petrochemical products (Manahan 2000; Johnson et al. 1985; Grimmer and Pott 1983; Hites, Laflamme. and Windsor Jr. 1980). PAHs are toxic and many of them are known carcinogens and mutagens (IARC 1983; UDHHS 1995). They are also listed as the U.S. Environmental Protection Agency priority pollutants (Keith and Telliard 1979). Photolysis transforms many organic pollutants to less toxic or harmless products. However, in the presence of natural or simulated sunlight, many PAHs become more toxic to aquatic organisms at concentrations that are well below the PAHs aqueous solubility limits (Landrum et al. 1987; McConkey et al. 1997; Hatch and Burton Jr. 1998). This may occur via photosensitization reactions (e.9.. production of singlet oxygen) (Ankley et al. 1994) and photooxidation of the compounds to more toxic products such as diols and quinnones (David and Boule 1993). Since the water solubility of PAHs increases after photolysis, aquatic organisms may be exposed to higher concentrations of the photoproducts than the parent PAHs. Therefore, the photoinduced toxicity may present a greater risk to aquatic organisms and ultimately humans, because of direct exposure andlor bioaccumulation through food chains. Biological monitoring of PAHs exposure has been mostly performed by measuring metabolites of PAHs in urine. 1-Hydroxypyrene (1-HP). a major metabolite of pyrene. has been proposed and used as a biological marker for monitoring occupational and environmental exposure to PAHs (Jongeneelen et al. 1986; Jongeneelen 1994; Angerer, Mannschreck. and Gundel 1997; Merlo et al. 1998). Recently, 1-HP was reported to be acutely toxic and genotoxic (Hauser. Schrader, and Bahadir 1997) and appeared to be more toxic to the test organisms than its parent compound- pyrene (Lambert. Kremer and Anke 1995). 1- nitropyrene (1-NP). a known mammalian and bacterial mutagen and a tumorigen in animals, is one of the most abundant nitro-polycyclic aromatic hydrocarbons in the environment (Herreno-Saenz 1995). 1-Aminopyrene (1-AP). a reduction product of (1-NP). has been reported to be a major metabolite during biotransformation of 1-NP by microflora in natural environment and in the guts of animals and humans (Tahara et al. 1995; Kinouchi et al. 1982; El-Bayoumy et al. 1983). Under UVA irradiation, both 1-AP and 1-HP have been shown to cause light-induced DNA single stranded cleavage (Dong’et al. 2000). Toxic metals are generated from both natural anthropogenic sources and become common contaminants in natural waters (Kuo and Genthner 1996; Moore and Ramamoorthy 1984). Their presence may significantly affect potentially important microbial transformation of organic chemicals in natural environment (Said and Lewis 1991; Kuo and Genthner 1996). The complexation of metal ions with organic ligands or species is a subject of great environmental relevance, because the availability and toxicity of both metals and organic chemicals to organisms strongly depend on their speciation (Sunda and Huntsman 1995; Xue and Sigg 1999). Copper and manganese were chosen in this study to assess their effect on PAHs mutagenicity, due to their importance in a variety of aquatic environments (Lasier. Winger. and Bogenrieder 2000; Markwiese and Colberg 2000). Bacterial in vitro assays have emerged as important ecotoxicological screening tools to monitor the hazrads of chemical contaminants in natural environment. In this study, the possible photo-induced genotoxicity and ecotoxicity of 1- HP and 1-AP were measured with a variety of bacterial bioassays. including viable bacteria counting, bacterial direct counting, heterotrophic mineralization of glucose and Mutatox Test. Mutatox determines the genotoxicity of chemical contaminants in liquid phase from environmental samples by measuring the changes of light emitted by a dark mutant strain of bioluminescent bacteria Vibrio fischeri strain -M169 (AXZUR). The test has been used as a rapid screening tool for detecting the mutagenicity of DNA-damaging substances (Sun and Stahr 1993; Johnson 1998). Glucose mineralization reflects bacterial counting and direct counting measure viability of heterotrophic bacterial populations and total number of bacterial populations respectively (Hwang, McCullum, and Slaughter 1998).
Utilitzation of in-house composted manure as a nutrient source for pine seedlings
Year: Authors: Merka W.C., Bush P.B., Thompson S.A., Morris L.A., Webster A.B.
At the present time, animal manures are generally viewed as waste materials with potential for water pollution rather than as a source of valuable plant nutrients that can be used for economic benefit. Much of the current mindset is toward regulation rather than beneficial utilization. To increase the value of layer manure rather than incur additional environmental costs, layer manure produced in a high-rise layer house was composted in the layer house. Beds of sawdusffshavings were placed under the cage rows so that manure excreted by the birds would be deposited on the surface of the sawdusffshavings beds. To promote composting. the sawdust shavings manure mixture was turned at 2-week intervals for a 246 day period. After this period, the dried compost had a N, P,O, and K,O content of 2%, 9%, and 5%, respectively. As a control, no sawdustlshavings mixture was placed on an additional 130 ft of manure line. After the same time period, the dried uncomposted layer manure that resulted had a N. P20,, and K20 content of 2%. 9%, and 5%. respectively. The P,O,-rich compost was evaluated in a greenhouse study to determine if it was a beneficial source of nutrients for the establishment of pine trees in the Georgia coastal flafwoods where the soils tend to be P deficient. Loblolly seedling growth was evaluated where potted seedlings received 0, 2, or 6 tons per acre equivalent of composted layer manure and several mixtures of primary and composted paper mill sludges. Pines receiving the 2-ton composted layer manure demonstrated the best growth rate. The growth rate of seedlings receiving the 6 ton per acre rate was reduced. This study suggests that the 2 ton per acre composted layer manure rate is acceptable for optimum nutrient utilization. Further experiments should be conducted applying composted layer manure at rates of 0.5, 1.0, 2.5, and 5 tons per acre to determine the optimum application rate for utilization of P.
The Effects of Ferric Iron on Photochemical and Microbial Degradation of 2,4,6 -Trinitrotoluene
Year: Authors: Cook S., Hwang H.M., Course H.
2,4,6 - Trinitrotoluene (TNT) has been used extensively as an explosive since 1902 (Higson 1992). Accidental release of TNT has contaminated groundwater and soil at numerous munitions manufacturing sites. It is estimated that TNT alone is produced in amounts close to 2 million pounds a year and threatens human life through the food chain (Hawari et al. 1999). The compound is mutagenic and toxic and has a tendency to persist in the environment. There have been many attempts to biodegrade TNT, but thus far the compound has been found to undergo biotransformation rather than degradation. The reported pathways for biological reduction of TNT have been the same as for chemical reduction. The nitro groups are reduced to the corresponding amines via nitroso and hydroxylamino intermediates. Reduction of the second nitro group does not begin until the nitro group has converted to the amine. Most microorganisms studied catalyze the preferential reduction of the 4-nitro group to yield 4-amino-2, 6 -dinitrotoluene (4ADNT) (Fiorella and Spain 1997). "Pink water" produced during photolysis of aqueous solutions containing mainly photodecomposed TNT and its photoproducts, is a complex mixture, which has been found to be more photosensitive than TNT. Some of these are; 4, 6- dintroanthranil, 2,4,6- trinitobenzyaldehyde (TNBAL), and 2,4,6- trinitrobenzyl alchohol (Burlinson et al. 1079). Ferric and ferrous iron, used by microorganisms for electron transport systems, has been shown to aid in the remediation of aromatic pollutants in water and soil in the form of Fenton’s reagent, which is a combination of ferrous iron and hydrogen peroxide. Photochemically, it has already been demonstrated that dissolved Fe (III) species undergo sunlight photoredox reactions on a time scale of minutes in atmospheric water. Thus, during daytime, the dissolved iron in atmospheric water drops is rapidly cycling between Fe (III) an Fe (II), very probably on a time scale of minutes, due to rapid (photo)redox reactions occurring n the water drops (Faust 1986). It is probable that similar mechanisms could be contributing to the iron redox cycling in acidic surface waters and perhaps even at the higher pH values encountered in oceanic waters (Faust 1994). In this study, a series of experiments were run to asses the rate of the transformation of TNT over time and the effectiveness of ferric chloride as a sensitizer to the combination of photochemical and biological transformation of TNT in samples of natural freshwater. This was done using HPLC analysis and radiotracing techniques.
Willingness to Pay for Precision Application Technology to Reduce Agricultural Nonpoint Pollution
Year: Authors: Hite D., Hudson D., Parisi D.
Agricultural production practices have been identified as the predominant contributing factor to nonpoint pollution (NPP) in the United States at present. State water quality surveys of fresh water bodies conducted under the auspices of the US Environmental Protection Agency (USEPA) suggest that great strides have been made towards achieving the goals of the Clean Water Act. However agriculturally related NPP continues to degrade water quality. According to the surveys, NPP impairs the function of lakes, rivers and estuaries such that one-third of all fresh water bodies do not fully support designated uses (USEPA 1998). The externalities that arise from pollution originating from field runoff and practices at intensive confined animal facilities are significant. Among the adverse impacts on streams and lakes are reduction of biodiversity, aesthetic value, food supplies, and recreational opportunities, and increases in the cost of drinking water treatment. Recent developments in the area of precision agricultural technology have demonstrated potential to reduce agricultural NPP. In particular, precision application methods such as variable rate technology (VRT) can reduce runoff by either reducing the overall application rate of chemicals and fertilizers, or by ensuring their optimal uptake by crops being grown. Specifically, VRT combines the use of MIS (Management Information System) with GPS (Global Positioning System) to optimize variable rate applications over subunits of a farm, resulting in decreased runoff of nutrients, pesticides and other chemicals as opposed to conventional single rate application. VRT has been shown to decrease input costs while increasing yields and economic returns as compared to conventional application (Blackmore et al. 1994; Leiva et. al. 1997). In addition, VRT holds promise for reducing NPP, as has been demonstrated through simulation experiments (Hite et al. 2000). However, precision application technology involves a large fixed cost for equipment that producers may not wish to incur, primarily because of uncertain effects of VRT on profits. Increasing agricultural production and improving water quality are public policy goals of national importance, which VRT may help to achieve. Thus, public programs to assist producers may be needed in order to promote VRT adoption. In this paper, we present the results of a pilot contingent valuation survey that was designed to assess willingness to pay (WTP) for a program to support implementation of precision application technologies. We use the results to investigate public perceptions of agricultural NPP, to assess attitudinal and demographic factors affecting WTP for agricultural NPP abatement based on precision application technology, and to provide estimates of WTP for implementation of the program.
The Mississippi waste pesticide collection and disposal program
Year: Authors: Crowe C.R.
Mississippi farmers use more than 44 million pounds of agriculture pesticides each year. Through the years, some of these pesticides have become unusable because their label registrations have either been canceled or suspended by the United SWes Environmental Protection Agency (EPA). These unusable products, whether they are the result of regulatory action or simply lefl over from a previous growing season, are classified as waste pesticides. Waste pesticides may lead to water quality problems as well as environmental and health concerns, especially when containers deteriorate or inadequate storage facilities are utilized. These substances cannot iegaliy be applied or disposed of through conventional methods such as landfilling. Recognizing this tremendous problem, the Mississippi Department of Agriculture and Commerce, Bureau of Plant Industry (BPI) began efforts to establish a pilot program for waste pesticide disposal in 1993. It was determined by BPI that a waste pesticide disposal program would be the best means of providing Mississippi farmers and private landowners with an economical and environmentally conscious way to dispose of their unwanted or otherwise unusable pesticides. As with any program, justification is always a key issue. The following are just a few of the reasons BPI used to justify the necessity of this program. Mississippi farmers and private landowners had no cost-effective way to dispose of their waste pesticides. Removing these hazardous chemicals from farms in which proper storage facilities were not available would eliminate a tremendous risk to the environment. Cancelled or suspended pesticide registrations by EPA are and will continue to be an issue in the future. Above all, a waste pesticide collection and disposal program would help prevent the occurrence of illegal disposal activities within the state.
Assessing the effectiveness of silvicultural streamside management zones: A research approach
Year: Authors: Young B.W., Schoenholtz S.H., Dibble E.D., Ezell A.W.
Forestry best management practices (BMP’s) are aimed at preventing or minimizing water pollution from non-point sources on lands undergoing forest management activities. One of the most common tools of any BMP strategy is the use of a streamside management zone (SMZ) (MS Forestry Commission 1995). An SMZ can be defined as any vegetated area adjacent to a stream or other watercourse that serves as a buffer between the water resource and an area of disturbance. Streamside management zones adjacent to logging sites are believed to protect water quality by slowing the rate of overland flow, serving as catchments for sediment and nutrients, and minimizing changes in streamwater temperature (Coleman and Kupfer 1996; MS Forestry Commission 1995). Although SMZs are widely used in forestry practices in the Southeastern U.S., the majority of research on SMZs has focused on their application in agricultural settings (Duda and Johnson 1985). With the exception of one study conducted in the Loess Hill Region of Mississippi (Keim and Schoenholtz 1999), there are no published reports of SMZ effectiveness adjacent to logging activities in the Gulf South (Comerford et al. 1992). Forest harvesting activities have increased dramatically throughout the Gulf South during the past two decades and the use of SMZs is widely practiced as a part of these activities in order to protect streamwater quality. Thus, there is a critical need to assess the effectiveness of SMZ’s in relation to forest harvesting activities in the Sand-Clay Hills Subsection of Mississippi, an area that is under intensive management for production forestry. This study is designed to evaluate the effectiveness of SMZs in protecting water quality adjacent to forest harvesting activities. The purpose of this paper is to present our research approach for studying effectiveness of forestry SMZ’s.
Streamflow and water quality of tributaries to the Noxubee National Wildlife Refuge
Year: Authors: Roberts B.A., Runner M.S.
The U.S. Geological Survey collected data at four locations on two streams flowing into the Noxubee National Wildlife Refuge in east-central Mississippi during the period of July 1998 through June 1999. The purpose of the data collection was to compare streamflow and water-quality data for Hollis Creek, which receives runoff from Starkville and the surrounding area, to data for Jones Creek, which drains predominantly undeveloped area. Discrete data were collected on stream discharge suspended-sediment concentration, temperature, pH, specific conductance, dissolved oxygen, 5-day biochemical oxygen demand, fecal-coliform bacteria, turbidity, and nutrients. Continuous data were collected on temperature, pH, specific conductance and dissolved oxygen at one station for two periods during the study.
Swine effluent irrigation rate and timing effects on bermudagrass growth, N and P utilization, and residual soil N
Year: Authors: Adeli A., Varco J.J.
Proper and efficient management of swine ;agoon effluent on cropland is important for improving the economics of crop production and for minimizing adverse impacts on soil and water quality. Confined swine feeding operations in Mississippi produce large quantities of waste which is flushed into anaerobic lagoons to facilitate digestion. To prevent lagoon overflow, surrounding crop land and pasture is irrigated with the effluent. The resulting effluent is a solution containing multiple nutrients including N. P, K. Ca, and Mg (Sutton et at.. 1982). Nitrogen and P make up the most agronomically and environmentally important proportion (Sutton et al., 1982). Sutton et al. (1978) reported concentrations of 480 pg N ml-’ and 103 pg P ml-’ in swine effluent Irrigation with swine lagoon effluent requires crops that assimilate large quantities of nutrients. Hybrid bermudagrass [ Cynodon dacfylon ( L.) ] has the potential to remove greater amounts of N and P compared to other crops due to its extensive root system and high biomass production potential (Woodhouse and Griffith, 1973). Efficient crop utilization of N and P derived from anaerobic swine lagoon effluent is critical to minimizing offsite nutrient movement. Burns et al. (1990) showed a bermudagrass yield response up to 670 kg N ha derived from swine effluent. Nitrogen recovery by ‘Coastal’ bermudagrass for a seven year period averaged 73%, 57%, and 34% for swine effluent application rates equivalent to 335, 670, and 1340 kg N ha-&rquo; (Burns et al. 1990). Phosphorus recovery by bermudagrass was 41%, 28%, and 17% with effluent application rates equivalent to 78, 153. and 301 kg P ha-’, respectively (Burns et al., 1990). Effects of swine effluent on forage yields and nutrient removal has generally been with excessive N loading and more of a means of disposing the waste rather than efficient utilization of nutrients. King et al. (1990) reported NO, -N accumulation below 60 cm with excessive N rates. Improving the utilization efficiency of nutrients derived from effluent by forage grasses require a better understanding of irrigation timing and rate effects. Morris and Celecia (1972) found more efficient N removal by bermudagrass when N was applied during the summer compared with fall application. Eichhorn (1989) found maximum bermudagrass yields at 448 kg N ha’ from fertilizer, while N removal continued to increase at N rates up to 672 kg N ha-. Percent N recovery decreased as rates increased from 224 to 672 kg N ha- (Eichhorn 1989). Timing and rates of fertilizer N application can affect both the availability of N for crop growth and the amount of NO,’ -N remaining in the soil profile (Jokela and Randall, 1989). Zebarth and Paul (1993) reported that there is negligible N benefit for corn following fall applied dairy cattle manure. Application of fertilizer N during the most active period of bermudagrass growth resulted increased yield, N removal and fertilizer N recovery compared with late season applied N (Shannon et al.. 1999). To reduce the potential for environmental degradation due to the high content of nutrients especially N in the swine effluent, application rates must not exceed the plant and soil buffering capacities. Application rates greater than optimal can cause an accumulation NO; -N in the soil profile (Bundy and Malone. 1988; Jokela and Randall, 1989; Roth and Fox, 1990). Although N sources and rates have been comprehensively evaluated for bermudagrass, relatively little is known about bermudagrass yield and nutrient utilization from swine effluent. Currently swine producers are permitted to begin swine effluent irrigation 1 March and continue until 31 October. This time interval is longer than the most active growth period of summer grasses such as bermudagrass. The objective of this study was to determine the effects of swine effluent irrigation rate and timing on bermudagrass growth. N and P recovery, and post- season soil profile NO;-N.
Pilot-scale swine odor reduction bioreactor system (SORBS)
Year: Authors: Kirkpatrick A.P., Burcham T.N., Zappi M.E., Nguyen A.T.
Odors associated with livestock production, particularly swine production, have drawn much media attention during recent years. The control of odor from livestock facilities is actively being researched. As the concentration of animal at a given site increases, the problems associated with odor control will become more problematic (Burcham 2000). Public concern with regard to odor associated with primarily swine production has resulted in moratoriums on industry expansion in the states of North Carolina and Mississippi (Hayes 1999). These factors resulted in a research effort by the Mississippi Agricultural and Forestry Experiment Station (MAFES) at Mississippi State University (MSU) to develop a cost-effective biological treatment system. This system is now in the pilot-scale development stage and is called the Swine Odor Reduction Bioreactor System (SORBS). The SORBS was designed with the primary goal of reducing odor associated with large-scale swine production. The SORBS uses "attached growth" biological treatment to reduce the formation of odor compounds. While most "attracted growth" reactors use inorganic media (plastic, gravel, etc.), the SORBS uses plant fiber as the attached growth medium. In particular, kenaf (hibiscus cannabis), a plant in the okra family, is being utilized in the SORBS. Microorganisms, that naturally populate the kenaf fiber, process the wastewater and reduce the formation of odor causing compounds.
Maximum Known Floodflows in Mississippi
Year: Authors: Wilson, Jr. K.V.
Maximum floodflows that are known to have occurred on Mississippi streams were compiled. Most of these data were collected and archived by the U.S. Geological Survey in cooperation with Federal, State, and local agencies; however, some of the data were collected and provided by the U.S. Army Corps of Engineers. Maximum known discharges are plotted with drainage area and compared to an envelope curve derived from maximum known discharges from throughout the conterminous United States. The paper is limited to only presenting the maximum flood known to have occurred at a given gaged site, where stage and discharge measurements were obtained to determine the peak discharge, or at an ungaged site, where a flood was thought to be significant enough that an indirect measurement computation was done to estimate the peak discharge. Maximum known floodflows can provide a better understanding of the hydraulic and hydrologic characteristics of extreme flooding at a particular stream site. Extreme flooding is usually caused by large amounts of rainfall at a time when conditions allow the largest possible rates of runoff. Extreme flooding that has occurred in the past may be the best estimate of what could be expected to occur in the future.
The Effects of PH and Ferric Iron on Photochemical and Microbial Degradation of Atrazine in a Freshwater Environment
Year: Authors: Glover H.E., Hwang H.M., Oatis J.
The herbicide atrazine is a photosynthetic inhibitor used to selectively control broadleaf weeds in agricultural crops. The half-life of atrazine in aquatic environments has been found to range from 3 days to over 8 months. Numerous environmental factors (including pH, light intensity, and inorganic salts) affect the degradation of atrazine. Photolysis and microbial degradation both have been shown to be important degradative processes affecting many organic pollutants in aquatic environments (Hwang et al. 1996). Photosensitizers have been used to induce or amplify the rate of photodegradation for several compounds including atrazine (Rejto et al. 1993). However, photoinduced toxicity has been reported for some organic contaminants (Landrum et al. 1987; McConkey et al. 1997). Iron is a common component of the earth and a trace nutrient. Ferric iron acts as a natural catalyst in aquatic photochemical reactions (Faust 1994). The use of ferric iron in the photodegradation of atrazine has been recorded in several studies. Most studies range between pH 3 and pH 8, and rely on formation of active oxidants (Balmer and Sulzberger, 1999; Arnold, Hickey, and Harris 1995). Ferric chloride is a strong oxidant used in water treatment plants and the printing industries. It has been used to form counter ions as well in organic degradation studies. Hydrolysis of atrazine occurs at both alkaline and acidic pHs and may be important for atrazine transformation (Trotter et al. 1990). Studies have also shown that isolated pure cultures and stable mixed communities may aid in biodegradation of s-triazines and their photoproducts, but there is very little information on the presence of ferric salts and their effects on atrazine degradation (McMahon and Chapelle 1992; Shapir, Mandelbaum, and Jacobsen 1998; Kontchou and Gschwind 1999). The objective of this study was to attempt to assess the quantitative effects of ferric iron salts and initial pH adjustments on microbial communities during atrazine degradation.
Maximizing nutrient uptake through forage crop selection
Year: Authors: Brink G.E., Rowe D.E., Pederson G.A.
The long-term application of animal manure to agricultural land has increased the potential for nutrients, particularly phosphorus, to enter and impact surface and ground water (Daniel et al.. 1998). The growth of the confined swine feeding and broiler industry in the Southeastern USA has resulted in greater manure application to forages. Nutrient uptake and export through forages may serve as a component of nutrient management planning. Hybrid bermudagrass responds readily to increasing nitrogen rates from either inorganic or organic sources (Overman et al., 1993). When swine effluent was applied to ’Russell’ hybrid bermudagrass to provide 560, 1120, and 2240 kg N ha.’ per year, a yield response similar to that for inorganic N was observed, but efkiency of N and P recovery declined quickly with increasing effluent rate (Liu et al., 1997). Applying effluent at the two higher rates resulted in large additions of N and P that were not recovered in the forage and were potential contributors to ground and surface water pollution. In North Carolina, Burns et al. (1985) reported that ’Coastal’ hybrid bermudagrass receiving 670 kg N ha" and 153 kg P ha.’ from swine effluent removed an average of 382 kg N ha. ’ and 43 kg P ha" per year. Nutrient uptake by common bermudagrass. prevalent throughout much of the Southeast, has not been compared with that of hybrids. Temperate forage species, which include annual ryegrass, annual clovers, small grains, and some perennial species, are an integral component of many forage-livestock systems in the region. These forages are planted in late summer or early fall in a prepared seedbed or oversown on a perennial grass sod, and grazed during the winter and spring (Bagley et al.. 1988). They provide high quality forage during a period when cool temperatures limit tropical grass growth. Poor drying conditions often limit producers’ ability to make hay from these forages until late spring. Annual ryegrass is the primary temperate species utilized due to its adaptability to a broad range of soil and climatic conditions, ease of establishment, late maturity compared with small grains, excellent forage quality (Balasko et al., 1995). and tolerance of close, continuous stocking (Ballet al.. 1991). The Southeast is also the primary producer of broiler chickens in the United States. Approximately 70% of the broiler chickens produced nationally in 1998 were produced in Texas, Arkansas, Tennessee, Mississippi, Alabama, Georgia, South Carolina, and North Carolina (NASS. 1998). Alarge proportion ofthe litter (a mixture of manure, wasted feed, feathers, and wood shavings or other crop residue) is applied to hay fields and pastures. Application may occur anytime during the year, depending on when a flock is removed from the house. If litter is applied to a dormant tropical grass hay field or pasture during the winter and spring, the presence of an oversown temperate forage will reduce the potential for nutrient loss through runoff, largely by reducing sediment movement (Sharpley, 1994), and leaching (Brandi-Dohrn et al.. 1997; Shipley et al., 1992). Nutrients will also be taken up by the temperate species if it is harvested for hay in the spring (Brink and Rowe. 1999). Temperate forage species can thus serve in both a feed and nutrient management role in hay and pasture systems receiving broiler litter as a fertilizer source. Because phosphorus concentration tends to fluctuate little relative to other nutrients, P uptake is generally a function of herbage yield, which may vary greatly depending on management, soil type, weather, quantity of nutrients applied, and cultivar (Robinson, 1996). In this paper, we report results from several investigations to determine the nutrient uptake of diverse perennial and annual forages receiving swine effluent and broiler litter.
Hydrologic Atlases Showing Areas Flooded by Hurrincan Camille Tides of August 18, 1969, Along the Mississippi Gulf Coast
Year: Authors: Wilson, Jr. K.V.
The approximate areas flooded by Hurricane Camille tides of August 18, 1969, along the Mississippi Gulf Coast are shown in a series of 14 hydrologic atlases. The area covered by the series of atlases extends from Bayou La Batre, Alabama, westward along the gulf coast through Mississippi to the mouth of the West Pearl River, a distance of about 90 miles. On November 10, 1969, 12 weeks after Hurricane Camille made landfall, the U.S. Geological Survey made public distribution of these atlases. The atlases are the culmination of effort that began soon after the hurricane made landfall in the Waveland and Bay St. Louis, Mississippi, area late during the night of August 17, 1969. The U.S. Geological Survey recognized the need to get the data to the public as soon as possible because any realistic and effective settlement of insurance claims and plans for rebuilding in the devastated area would require the delineation of the land area flooded. The U.S. Geological Survey was able to produce in 3 months a series of atlases that would have normally required one to two years to complete. The U.S. Geological Survey used the data shown on these atlases as a guide to storm-tide flood elevations caused by Hurricane Georges, which made landfall on September 28, 1998, in the Ocean Springs and Biloxi, Mississippi area. Hurricane Georges was considered a strong Category 2 hurricane, and Hurricane Camille was considered a category 5 hurricane. The maximum storm-tide elevation surveyed for Hurricane Georges was 11.0 feet above sea level near Pascagoula; at the same location, the storm-tide elevation for Hurricane Camille was 12.7 feet above sea level. The maximum elevation for Hurricane Camille was 24.2 feet above sea level at Pass Christian; at the same location, the elevation for Hurricane Georges was 7.0 feet above sea level.
The Carbonate Island Karst Model
Year: Authors: Mylroie J., Jenson J.
Tropical carbonate islands (and analogues along tropical carbonate coasts on continents) are a unique karst environment that differs significantly from that found n temperate continental interiors, where most cave and karst research has historically been done (e.g. White, 1988: Ford and Williams, 1989). The differences center on three factors (Mylroie and Vacher, 1999): 1) fresh water - salt water mixing occurs within the fresh-water lens; 2) glacioeustasy has moved the freshwater lens up an down through a vertical range of over 100 m; and 3) the karst is eogenetic, i.e., it has developed in carbonate rocks that are young and have never been buried beyond the range of meteoric diagenesis. The outcome of the first factor is that enhanced dissolution results from the mixing of fresh and saline waters at the base and margin of the lens (Plummer, 1975). This dissolution in the lens base is augmented by the enhanced dissolution at the top of the lens produced by mixing of fresh vadose and phreatic waters (Bogli, 1980). These dissolution effects modify the shape of the lens over time. The consequent increase n hydraulic conductivity in the rock permeated by the lens eventually results in a thinner lens. The second factor, glacio-eustatic variation of the lens position-and variation in the time during which the lens occupies any given positioning the section-results in a complex variation of porosity and hydraulic conductivity over the section of carbonate bedrock. If later carbonates are added above or adjacent to the original units, the lens will be thicker in the younger carbonates that in the older ones, creating a significant departure from an idealized lens shape (Vacher, 1988). This phenomenon is somewhat counter-intuitive, as the younger rocks often have a higher primary porosity than the older rocks. However, dissolution has rearranged the original porosity into preferred flow paths, and the hydraulic conductivity is thus greater in the less porous older rocks. Along the margin the lens, flow velocity increases and the mixing zones at the top and bottom of the lens converge to form flank margin caves, typically the largest voids observed on small carbonate islands (Mylroie and Carew, 1995). Flank margin caves are not true conduits, but mixing chambers. Their position with respect to the margin indicates former sea-level stillstands, and their size and spacing along the island margin are indicators of past flow conditions within the associated paleo-lens. The main consequence of the third factor is that progressive diagenesis everywhere throughout young, highly porous carbonates results in a reordering of the host rock porosity. Development can also be influenced by the nature of the depositional environment of the carbonate rock, which can vary from eoliam, logoonal, shoal or reef. Variations in island size create differences in catchment and lens volume/island perimeter ratios that might inhibit conduit development in small carbonate islands but favor it in larger ones (Mylroie and Vacher, 1999). Young carbonates have not undergone the deepburial diagenesis associated with older rocks. Such older rocks commonly lack significant primary porosity, and water flow is primarily via bedding planes, joints, faults or fractures. They are best modeled as dual porosity aquifers combining fracture and conduit flow. Eogenetic carbonates, as found in tropical islands, retain significant primary porosity, and their eogenetic processes superimpose a vuggy porosity and permeability on that primary system, which in turn feeds conduit flow to create a triple porosity aquifer. As a result of the effects of fresh water - salt water mixing, sea level change, and eogenetic evolution of the carbonates, carbonate islands contain karst features and caves remarkably different from the typical fluvial karst formed in dense Paleozoic and Mesozoic carbonates of continental interiors.
Perspectives on Poultry Waste Management
Year: Authors: Blake J.P.
Chief among problems facing the poultry industry are those of waste management and associated environmental issues. Today the poultry industry is larger, more concentrated, and more technically advanced than it was one or two decades ago. The concentration of the poultry industry has resulted in the production of large volumes of by-products including: manure, farm mortalities, hatchery, and processing plantwastes that requiredaily attention. The poultry industry has responded well in objectively evaluating economically and environmentally sound management principles in dealing with by-product utilization as opposed to disposal. Many of the so-called wastes, if managed and processed appropriately, have the potential for increasing the economic profitability of the poultry operation. Disposalof poultry by-products has been identified by the poultry industry as a priority. Poultry producers must plan and manage their operations in a way that is safe for the environment. Poultry wastes, if improperly managed, can cause problems in the environment and can create hazards to human and animal health.
Dechlorination of PCBs and CAHs Using NA/NH3 Application to Soil Remediation
Year: Authors: He J., Pittman, Jr. C.U.
Remediating toxic compounds from soils prevents subsequent leaching into groundwater. Model halogenated aromatic, aliphatic and olefinic hydrocarbons and halogenated phenols were dehalogenated in seconds by solvated electrons generated from sodium in both anhydrous liquid ammonia and ammonia/water solutions. The minimum amount of sodium required to completely dehalogenate these model compounds was determined by increasing the Na/substrate ratio until halogen loss was complete. Minimum sodium consumptions were determined in both anhydrous liquid ammonia and with a (5, 20, 50-fold molar excess of water per mole of halide) present. While more Na was consumed in the presence of water, these dehalogenations were still efficient when a 50-fold water excess was present. Dehalogenation is faster than competiting reactions with water. CCl4, CH3CCl3 and CCl2=CCl2 in the presence of a stoichiometric deficiency of sodium produced only Ch4, CH3CH3 and ethylene and recovered CCl4, CH3CCl3 or CCl2=CCl2, respectively. No partially dechlorinated products were detected, indicating each dechlorination was diffusion controlled. Na consumption per chlorine removed (as NaCl) was lower than that of Li, K or Ca and this advantage increased in the presence of water. This work was extended to PCB- and CAH contaminated soils (both wet and dry). PCBs were remediated with 99.9% and higher efficiencies by slurrying soils in NH3 followed by addition of sodium. Soils contaminated with CAHs were remediated from 4000 - 3000 ppm levels to ~1 ppm. The required sodium consumption per Cl removed was determined in both wet and dry soils. As the concentration of CH3CCl3 in soil decreased, larger amounts of sodium were required (per Cl removed) to further destroy the remaining CH3CCl3. However, even in wet soils, the sodium consumption was not excessive. This method also destroys polynuclear aromatic hydrocarbons (PAHs) and nitro compounds found in contaminated soils around munitions plants.
Roles for Regional and Local Agencies to Integrate Source Water Protection into Basin Management: Mississippi’s Upper Pearl River Basin
Year: Authors: Ballweber J.A.
Basin approaches have long been used to plan and implement navigation, flood control and certain agricultural conservation programs. Environmental concerns were never truly integrated into those efforts. Several overlapping "watershed/basin approaches" are evolving to remedy this defect. Federal basin management policies propose a flexible framework to encourage states to develop and implement more formal Basin Approaches. For instance, Mississippi’s Department of Environmental Quality (MDEQ) recently adopted a Basin Approach to Water Quality Management to resolve litigation relating to Mississippi’s Clean Water Act 303(d) list and the preparation of Total Maximum Daily Loads waterbodies on that list. Simultaneously, a Mississippi Source Water Assessment Program plan was developed to satisfy the Safe Drinking Water Act’s Source Water Assessment Program. Existing basin management programs show that environmental basin approach policies will only succeed to the extent that intrastate regional and local agencies voluntarily participate in developing and implementing specific basin management plans. To maximize personnel and financial resources and avoid duplication, a single, comprehensive integrated Basin Approach is more practical than many parallel perhaps competing approaches or management efforts. This paper has two goals: 1) introduce federal and Mississippi environmental basin-scale initiatives and opportunities to use MDEQ’s Basin Approach to integrate water quality and safe drinking water requirements into a single basin plan, and 2) analyze the application of these initiatives in Mississippi’s Upper Pearl River Basin and identify roles for the Basin’s regional and local water and related land management agencies and its agricultural watershed projects in implementing MDEQ’s Pearl River Basin Management effort.
Fractionation of accumulated copper in soils of catfish ponds receiving weekly, low-rate applications of copper sulfate
Year: Authors: Han F.X., Hargreaves J.A., Kingery W.L.
Copper sulfate (CuSO,) is applied to fish ponds as a therapeutant and an algicide. Complete death of the phytoplankton bloom in a fish pond is undesirable as phytoplankton plays a critical water quality maintenance role. Regular, low-rate applications of CuSO, may achieve a more desirable, partial reduction of a phytoplankton bloom. However, knowledge of copper chemistry in aquatic systems suggests that it may accumulate in pond soils. This study investigated the accumulation and distribution of Cu in the soil of catfish ponds receiving weekly, low-rate applications of CuSO, over two years. Eighteen 0.40-ha earthen ponds were stocked with channel catfish at 10,00O/ha. Nine ponds received fifty applications of 2.27 kg CuSO, per application per pond over two years (total = 113 kg Cu/ha); no CuSO, applications were made to nine additional ponds. All CuSO, applications were made during the growing season (May-September). Upon completion of the study, after ponds were drained, the surface 5-cm layer of pond soils was sampled with a core tube (37/ha) and composited. Air-dried Soils were sequentially extracted to de:ermine the proportion of copper in the following fractions: water soluble (available), exchangeable, organic matter associated, easily-reducible oxide, amorphous iron oxide, crystalline iron oxide, carbonate, and residual. Nearly all the Cu applied to ponds could be accounted for in pond soils. The concentration in soil from CuS0,-treated ponds (175 mglkg) was seven times higher than that in non-amended pond soil. Copper in amended pond soils was mainly in the carbonate (30%). organic matter (30%) and amorphous iron oxide (20%) fractions, with high levels in the soluble and exchangeable fractions (3- 8 mg/L), indicating that considerable copper can accumulate in some of the highly labile phases of amended pond soils. Additional research is required to evaluate the effects of accumulated copper on water quality in ponds with a history of copper sulfate application that extends beyond the time frame of the study described here.
Field Study for Evaluating Effluent and Groundwater Use Reduction in Catfish Ponds
Year: Authors: Rutherford D.W., Cathcart T.P., Hargreaves J.
A hydrological management strategy designed to reduce the volume of effluent discharge and groundwater use in catfish ponds was modeled by Cathcart et al. (1999). The modeled system uses deepened "production/storage" ponds to hold and reuse rainwater in lieu of groundwater in conventional production ponds. Model predictions suggested that this approach may reduce effluent discharge and groundwater use by up to 70%. The approach is currently being implemented in a 3 year field study to test the assumptions of the model. Seven 1-acre ponds located at the Delta Research and Extension Center (DREC) in Stoneville, MS have been modified for this purpose. Tested configurations include 3 production ponds linked to 1 production/storage pone; 1 production pond linked to 1 production/storage pond; and a control pond. Effluent volume data from each pond system are being collected using a 30 cm H-flume connected to each of the production/storage ponds and a pressure transducer for flume depth readings. Equations for known depth/volumetric flow rate relationships of a 30 cm H-flume are being used to calculate effluent volumes. The systems have been calibrated and installed and data is being collected. When required, the volume of groundwater added will be calculated by measuring depth changes in the ponds. After collecting data for effluent produced and groundwater used, the field data will be compared to model predictions for the same conditions. If predicted and observed performance agree reasonably well, the authors feel that this approach will be a viable alternative for producers in the face of increasingly stringent requirements by regulating agencies.
Agriculture and water quality has farming become public enemy number one?
Year: Authors: Parrish D.
The Federal Water Pollution Control Act of 1972 was the first serious attempt by Congress to address the nation’s water pollution problems. Congress reauthorized the Act in 1987 and renamed it the Clean Water Act (CWA). The fundamental premise of the Act was to make it unlawful for anyone to discharge any pollutant from a "point source". Understanding the impractical and impossible goal of "no discharge," Congress fashioned the bulk of the CWA as a detailed road map so regulatory agencies had a method of regulating the discharge of a pollutant to get around the unattainable "no discharge" rule. To achieve this, Congress focused primarily on "point source pollution," and enacted a scheme known as the "National Pollution Discharge Elimination System" (NPDES). The CWA prohibits the discharge of pollutants into navigable waters without an NPDES permit. The NPDES is a federally mandated and supervised permit system. The U.S. Environmental Protection Agency (EPA) has primary authority for implementing the CWA. The CWA grants EPA the authority to regulate any discharge of a pollutant from a discharge of a pollutant from a discrete point source. But there are limits to EPA’s authority that are outlined by the definition of two key CWA terms: "discharge of a pollutant" and "point source."
Environmental fate of fluometuron in soil influenced by best management practices (BMPs)
Year: Authors: Shaw D.R., Blanche S.B., Shankle M.W., Kingery W.L., Massey J.H.
Fluometuron is an effective herbicide for annual grass and broadleaf weed control in cotton, Several fluometuron applications applied per growing season may include a preemergence, postemergence when cotton is 7.5 to 15 cm, and postemergence at lay-by (with the last cultivation). The mode of action is inhibition of photosynthetic electron transport by binding to the D1 protein of photosystem II and blocking electron transport from QA to QB (Ahrens 1994). Fluometuron was labeled for use in 1965 (Timmons 1970) and is one of several compounds that belong to the herbicide group known as the phenylureas or substituted ureas. These compounds have three hydrogen atoms of urea replaced or substituted with a variety of carbon chains and rings. Fluometuron is unique from other compounds in this group due to a trifluoromethyl group at the meta position of the phenyl ring (Rickard and Camper 1978). Fluometuron is considered to be a nonionic molecule that does not ionize over a wide pH range (Patterson et al. 1982). Water solubility is 90 mg L ’ at 20 to 25 C and is categorized as moderately water soluble (Weber 1972). Fluometuron was the herbicide of choice to evaluate because cooperating producers at all the MD-MSEA locations apply fluometuron. and detectable levels have been reported in surface water (Coupe et al. 1998; Pereira and Hostettler 1993). Previous research suggests that herbicide and sediment in runoff is reduced as it moves through grass filter strips and riparian areas. Therefore, research objectives were: to characterize soil properties within different areas of a new (< 1 yr) grass filter strip, established (> 5 yr) grass filter, and a riparian forest to determine the impact of different BMPs on soil properties and the spatial distribution of soil particles within BMP areas; and determine fluometuron adsorption and degradation to these soils to assess the ability of soil from these BMPs to retain fluometuron.
U.S. Geological Survey Crest Stage Gage Network in Mississippi
Year: Authors: Massingill D.K., Turnipseed D.P.
Determining the magnitude and frequency of floods is a paramount in the design of bridges, highway embankments, culverts, levees, dams, and other flow-control structures. The reliability of flood-frequency analysis is largely attributed to the length of the period of record and accuracy of the flood information. A practical and cost-efficient means of collecting long-term, site-specific, flood-stage data to assist in the determination of flood frequency can be accomplished by using crest stage gages. The U.S. Geological Survey began collecting peak-stage and discharge data in Mississippi in 1899. In the late 1940’s, the USGS in cooperation with the Mississippi Department of Transportation, the U.S. Army Corps of Engineers Mobile District, and the City of Jackson, began the systematic collection of flood-peak data using a network of crest stage gages. The primary type of crest stage gage used in the state is a 1.5 to 2 inch galvanized pipe from 5 to more than 20 feet long housing a 1-inch aluminum tee. The bottom cap has six holes arranged to prevent drawdown and/or pileup of the water within the pipe. The top cap has a small hole to vent to the atmosphere. Inside the pipe, attached to the bottom end of the aluminum tee, is a plastic or metal cup containing regranulated cork. As the water rises inside the pipe, the cork floats on the water surface. On the recession of the water surface, the cork adheres to the tee, thereby recording the crest stage of the flood. This simple, economical and very reliable system has provided the USGS a means of collecting flood crest stages for more than 50 years. Currently, the USGS Mississippi District maintains 72 crest stage sites for the collection of peak-stage and discharge data throughout the state. The range in drainage areas is from 0.10 square miles (Red Cane Creek near Pisgah, Mississippi) to 495 square miles (Leaf River at Taylorsville, Mississippi). During flooding events, when flood waters are on the crest stage gages, crews from the USGS office in Pearl, Mississippi, measure discharge at these locations to determine a stage/discharge relation. Many of the crest stage gages are located at box culverts. Discharges at box culverts are computed based on predetermined hydraulic characteristics that include the geometry of the culvert and upstream and downstream peak elevations of a given flooding event. The annual peak stage and discharge for each crest stage gage is published in the USGS Water Resources Data book series. Annual peak discharges at crest stage gages are also used in the analysis of flood frequency for the state.
Effects of irrigation on bermudagrass grown on soil heavily fertilized with poultry litter for 40+ years
Year: Authors: Rowe D.E., Brink G.E., Sistani K.R.
It is now understood now that long term land application of animal manures may result in high concentrations of the soil nutrients, nitrogen and phosphorus. As those concentrations increase the potential for pollution of runoff water may also be increased. Remediation is effected on these fields to reduce the concentrations of nutrients through proper management of forages so nutrients are removed from the soil in the harvested hay. The forage yield is optimized using management which also insures that the soil surface is protected from erosion. Some researchers have postulated and some research has indicated that fields long used for waste disposal still respond to supplemental nitrogen applications (Halverson. 1989 ). This suggests that nitrogen may be limiting, possibly because the nitrogen content of the animal waste is modest in contrast to the phosphorus content. The amounts of nitrogen and phosphorus in the forages be in a ratio near 8:l while the animal waste used as a fertilizer may have a nutrient concentrations in ratioscloserto4:l (Sharpley and Halvorson. 1994). Other researchers have found that phosphorus contents of leaves, stems, and other plant parts do vary and have suggested that breeding might be used to increase the amount of phosphorus removed in the harvested hay by simply increasing the quantity of that plant part or the relative percentage of biomass for that plant part (Pederson and Brink, 2000). This approach appears successful for the improvement of alfalfa hay protein with use of multifoliate gene to increase leaf mass relative to the constant stem mass. Increasing manure application rate generally increases forage yield, but not all of the nutrients in the effluent or litter may be available to the plant. For poultry litter, estimates of N volatilization shortly after field application are 10 to 37% (Kee et al., 1996). Soil storage of P may be near 90% of the total P applied (Scott, et al.. 1995). Estimates over four years of field tests suggest 25% of the N and less than 20% of the P in the applied manure were recovered in the harvested forage. The accumulation of nitrogen in the aboveground portion of plants in contrast to total N of the plant is estimated to be 75% for rye (Secale cereale L.), 90% for hairy vetch (Vicia villosa Roth). and 80% for crimson clover (Trifoliurn incarnaturn L.)(Shipley et al., 1992). The uptake of nitrogen may be underestimated because abundant N favors volatilization of NH, from the plant (Charpe. et al., 1988). Time of application does affect the rate of apparent uptake or recovery. With early applications of N about 40% of the N is recoved, but with late applications, 90% of the N is recovered (Bigeriego, et al.. 1979). Estimates of total plant N which is lost due to volatilization of NH, is 23% of the total plant N (Sharpe and Harper, 1997). Nitrogen unaccounted for in nitrogen balance studies are attributed to leaching, denitrification. or sampling errors (Sharpe et al.. 1988), but NH, loss from the plant may be much more important than previously thought. Researchers at WM&FRU proposed that irrigation might be an economically reasonable method of reducing the rate of approach to the limits of extractable P in the soil at which application rates are severely curtailed or application is terminated. Researchers are also aware that bermudagrass morphologically changes during periods of severe drought stress. Under drought, the stolons are relatively large and few but with irrigation to alleviate that moisture stress, the leaves are many and stems have small diameters. Thus the effects of irrigation are expected to be increased yields and changes in morphology of the plant. Any interaction of these two factors on the rates of nutrient removal is not predictable for the extraction of the major nutrients from the field. Bermudagrass was used in this stvi’y because it is recognized as an aggressive grasc which with its indeterminate growth habit increases in production of biomass as soil fertility is increased. Also, farmers know how to manage this forage and this grass has known nutritive and market value.
Toxicity assessment of sediment associated copper sulfate in a Mississippi Delta catfish aquaculture facility
Year: Authors: Huggett D.B., Schlenk D., Griffin B.R., Hargreaves J.A.
The use of copper sulfate in the catfish aquaculture industry is historic and widespread. Used primarily to prevent infections (i.e. lchthyophtirius mu/fifi/iis ) and algal blooms, copper sulfate may be applied to ponds several times a year at a suggested rate of 1 mg/L per 100 mg/L alkalinity (Schlenk et al. 1998, and Tucker and Boyd 1978). It has been observed in recreational lakes that copper sulfate has a short residence time in the water column after application ( ~ 2 4 h) (Button et at. 1977). Based on its water column residence time and its application rate, copper sulfate has the potential to concentrate in the sediment of aquaculture ponds. A practice in the aquaculture industry is the draining of catfish ponds. Often times, the ponds are drained from the top down between yearly catfish harvests, with the water being discharged into a receiving stream. Few studies have investigated the fate and effects of copper sulfate in aquaculture facilities, especially the effects on non-target biota in receiving streams. It is unknown to this point whether any of the applied copper is transported into receiving streams during pond draining, thus potentially effecting aquatic organisms. Information regarding the fate and effects of copper in aquaculture facilities will soon be of importance, since catfish aquaculture facilities may soon have to apply for and comply with National Pollutant Discharge Elimination System (NPDES) permits (USEPA 1998). In an effort to investigate the fate and effects of copper sulfate in aquaculture facilities, sediments were collected from catfish ponds and a stream which received discharge from the catfish ponds, which were treated with copper sulfate for a extended period of time. The specific objective of this study was to determine if copper sulfate added to catfish ponds was adversely effecting aquatic organisms in the ponds themselves or the stream receiving aquaculture discharge. Effects were quantified utilizing toxicity studies with the epi- benthic invertebrate Hyalella azteca, the aquatic macrophyte Typha latifolia and various chemical predictors (interstitial water). If no toxicity was observed, then sediments were to be spiked with additional amounts of copper sulfate to determine effects thresholds.
Measurement of 1999 Drought Conditions in Mississippi
Year: Authors: Turnipseed D.P.
Accurate and reliable water-resources data collected during drought conditions are critical to regulatory agencies such as the Mississippi Department of Environmental Quality (MDEQ). Droughts have affected Mississippi during 1940-44, 1951-57, 1962-71, 1980-82, and 1983-88. In late summer and early autumn 1999, many areas of Mississippi experienced near record drought conditions causing concern to many private and public interests. Personnel from the U.S. Geological Survey(USGS), in cooperation with the MDEQ Office of Land and Water Resources (MDEQ-OLWR), measured water levels and streamflows throughout the State of Mississippi during drought conditions in August through October 1999. Droughts are normal, recurring hydrological events caused by deficiency of precipitation over an extended period of time that can have adverse effects on anthropogenic use of water. Much of the State of Mississippi has continued to experience drought conditions through late winter of 2000. Data on minimum streamflows are an important factor for determining the regulation of flow control structures, effluent, and surface water withdrawals and other water-management decisions during droughts. Data on minimum streamflows become paramount during drought conditions. This report presents information related to the legal aspects of drought conditions and includes selected data collected at streamgages affected by severe drought conditions in Mississippi during the late summer and early autumn of 1999. Comparisons of 1999 low-flow characteristics at selected streamgages to other period-of -record low-flows at selected gages in the State are also presented.
Recovery of waterborne cryptosporidium parvum by freshwater clams in Mississippi
Year: Authors: Ballweber L.R., Siefker C., Dibble E.D., Gao W.
Parasites of the genus Cryptosporidium are protozoans that inhabit the gastrointestinal or respiratory tract of birds and the gastrointestinal tract of mammals, reptiles, and fish. Eight species of Cryptosporidium are currently recognized (Fayer et al.. 1997). although recent genetic analyses suggest more species probably exist (Morgan et al., 1998, 1999). Cryptosporidium parvum, which lives in the small intestine, is transmitted by the fecal-oral route via the oocyst. Depending on the immune status of the host, ingestion of oocysts results in either a severe, chronic or a self-limiting diarrheal disease in both humans and other mammals (Fayer et al.. 1997). In humans, individuals at greatest risk from infection are the young, the elderly, and those that are otherwise immunocompromised or immunosuppressed. In animals, the young are considered to be the group most at risk. Consequently, cryptosporidiosis is considered to be primarily a disease of animals within the first 1-2 months of life. There is currently no effective treatment for infection with this parasite and, if supportive therapy is not instituted, infections can be fatal. Of the species of Cryptosporidium recognized to date, only C. parvum was thought capable of infecting humans. However, identification of this parasite has been hampered by the fact that all species are morphologically similar. Traditional methods used to identify these parasites have rested on minor differences in oocyst size and whether the parasite can experimentally infect a specific type of animal. It is impossible to conduct infectivity studies with every isolate, yet, it is important to differentiate zoonotic isolates from those that are not. Recent advances in genetic techniques have been applied to this problem and have indicated that at least two types of C. parvum exist - one that apparently cycles among humans and a second type that cycles back and forth between humans and animals (Peng et al., 1997). Furthermore. genetic data suggests that at least one other species of Cryptosporidium - C. felis - and a third, as yet unidentified species of Cryptosporidium from dogs, may also be able to infect humans (Pieniazek et al.. 1999). As stated, the oocysts is the stage responsible for transmission of Cryptosporidium spp. Oocysts are unusually resistant to natural stresses and many man-made chemical disinfectants. This, coupled with their small size (3.5-5.5 Vm) and low sedimentation rate (0.5 lm/sec) enhances transmission of the parasite. Waterborne outbreaks of cryptosporidiosis have been documented and contributes to the recognition of C. parvum as the most important newly recognized contaminant in drinking waterworldwide. Rivers, lakes, springs, and ground water have all been implicated as sources of infection (see Rose et al., 1997; Smith and Rose, 1998). Surveys of surface waters throughout the US have shown oocyst prevalences of 6-100% and oocyst concentrations of 0.003-240 oocysts per liter of water (Graczyk et al.. 1997a; Rose et al.. 1997). Water contamination is, in part, thought to occur as a result of adverse weather conditions (heavy rains, snow melts, floods) which wash oocysts from land areas into surface waters or cause sewage ovefflow. The relative contribution of mammalian feces or human excreta to the pollution of the environment is currently unknown. Difficulties encountered identifying the source of contamination stems, in part, from lack of information regarding both the true role of sewage ovefflow. agricultural runoff, and wildlferal mammals as possible nonpoint sources of C. parvum and other zoonotic species of Cryptosporidium. Complicating the picture even further is the recent discovery that waterfowl, which do not become infected with C. parvum. can pass undamaged oocysts through the digestive tract (Grauyk et al., 1996; 1997b) that retain their ability to cause infections in mammals. This potential ability by birds to transport oocysts far from the original source could mean contamination of protected watersheds. Current US EPA water quality monitoring procedures for detecting and enumerating oocysts in surface water are incapable of distinguishing between isolates of C. parvum or between the other zoonotic and non-zoonotic species that could be present as well. In addition, these procedures are also incapable of determining when oocysts enter the system. Consequently, current methods are minimally effective as monitoring tools and in epidemiological investigations. Development of a more sensitive biomonitoring tool is needed. Freshwater bivalves have characteristics making them excellent candidates for biomonitoring (McMahon. 1991). They can develop extremely dense populations, have high filtration rates, are collectible year-round, and can be held in field enclosures. In addition, because adults of large species tend to remain in place, they are subject
Enteric bacteria as environmental bioindicators in stream water and sediments
Year: Authors: Halda-Alija L., Hendricks S., Johnston T.C.
A combination of classical microbiological tests, API 20E, and amplified ribosomal DNA restriction analysis was used to examine effects of farmland and rural development on the distribution of populations of Enterobacter species along the stream. The enteric bacteria were examined in an agricultural stream, Ledbetter Creek in Murray, Kentucky, USA over a period of 2 years and were significantly higher compared to a pristine stream, Panther Creek, Tennessee, USA. Ledbetter Creek is an agricultural stream where interstitial waters were less aerobic, with high nitrate (0.268 mg/L), high turbidity (14.1 mg/L), and high total suspended solids (14.1 mg/L). Total area of the site was approximately 300 m2. Five distinct patterns were differentiated among Enterobacter isolates recovered from stream water, streambed sediments and different hyporheic depths by ARDRA analysis. Different ARDRA types dominated at different depths. We concluded that Enterobacter species were heterogeneously distributed along the stream and distribution was influenced by site (streambed sediments, gravel bar, upwelling, downwelling), sampling time (winter, spring, summer, fall), occurrence of anaerobic zones, macronutrients, turbidity, and total suspended solids. The presence and movement of the enteric bacteria in the environment will significantly contribute to our understanding of bacterial populations in freshwaters and we suggest using enteric bacteria as environmental bacterial indicators.
Mississippi Delta Management Systems Evaluation Area - Insecticides in Runoff, 1996-99
Year: Authors: Southwick L.M., Rebich R.A., Fouss J.L.
Nonpoint source contamination of our Nation’s water resources has received much attention in the last decade. Potential nonpoint source contaminants include sediment, nutrients, and pesticides in watersheds that drain a variety of land use categories such as agricultural, forested, and urban areas. Although contamination due to sediment and, to a lesser degree, nutrients will most likely outweigh contamination from other nonpoint pollution sources, pesticides are probably the highest profiled and most highly publicized candidate. The concerns with pesticides not only focus on the potential impact to human health but also the impact on aquatic and wildlife habitat. There have been many studies that have focused on the occurrence, distribution, and impact of pesticides throughout the major watersheds in the United States. Studies in the 1970s focused on the impacts of the older organochlorine insecticides on both human health and aquatic habitat integrity. Most of these compounds are no longer used in the United States. Other pesticides have been developed that have shorter life spans and are less toxic. The current-use insecticides include organophosphates (such as malathion, parathion, dimethoate) and carbamates (such as aldicarb and carbofuran). While these chemicals do not tend to bioaccumulate or persist in the environment, they can be more acutely toxic than their organochlorine predecessors. The newest group of insecticides, the synthetic pyrethroid compounds, include esfenvalerate, cyfluthrin. and cyhalothrin. Synthetic pyrethroids typically are only slightly toxic to birds and mammals but are highly toxic to fish and other aquatic animals (Rollins et al. 1997). One of the most intensive agricultural areas of the United States is the Mississippi River Alluvial Plain in northwestern Mississippi, a 7,000-square-mile area locally referred to as the "Delta." The rich, fertile soils of the Mississippi Delta przduce a variety of crops such as cotton. soybeans, corn, and rice. The long growing season in the Mississippi Delta increases the dependency and frequency of pesticide use, especially on crops such as cotton that are highly sensitive to intense weed and insect pressures. Cotton grown in the Mississippi Delta receives about three to five times more applications of pesticides than does corn grown in the Midwest (Thurman et al. 1998). Because of the large amounts of pesticides used in the Mississippi Delta and the fact that the region is characterized with high regional rainfall (about 60 inches per year) and slightly permeable soils, there is concern for potential off-site movement of these compounds during runoff events. The US. Geological Survey (USGS) began operating an automated streamflow and water- quality sampling network in the fall of 1995 as part of the Mississippi Delta Management Systems Evaluation Areas (MDMSEA) project. The primary objectives of the network are to assess the effects of conventional and alternative agricultural practices on runoff water quality to oxbow lakes (Rebich 1997). Emphases of the USGS sampling program were placed on sediment, nutrient, and herbicide analyses. Additionally, in 1996, the USGS began providing samples to the US. Department of Agriculture, Agricultural Research Service (ARS), Soil and Water Research Unit, in Baton Rouge, LA, for insecticide analyses. From 1996 to 1997, the insecticide analyses included organophosphates and pyrethroids !Ised throughout cotton-producing areas in the Mississippi Delta. However, very few samples for insecticide analyses were available in that time period due to infrequent storm events and low sample volumes. In 1998. more emphasis was placed on low-level analyses of pyrethroid insecticides, and additional samplers were installed in cooperation with industry to ensure that samples would be collected for as many runoff events as possible. The purpose of this paper is to present selected insecticide concentration data for runoff samples collecte to date for the MDMSEA project from 1996 through 1999 and to estimate the impact of watershed-level best management practices (BMP’s) on the occurrence of insecticides in storm runoff.
Runoff of insecticides applied to crops in the the Mississippi Delta management systems evaluation area
Year: Authors: Southwick L.M., Fouss J.L., Rebich R.
For a three-year period (1997-1999) runoff from Mississippi River alluviai soil was analyzed for insecticides applied to various crops in the Mississippi delta near Greenwood, Mississippi. The samples were assessed for the presence of two pyrethroid insecticides, h-cyhalothrin and cypermethrin. and two organophosphates, methyl parathion and azinphosmethyl. The vast majority of runoff events occurred at times in excess of 30 days after application (DAA). In all samples collected at t > 30, no detections were observed (detection limits < 0.1 ppb for the pyrethroids and c 2 ppb for the organophosphates). Only once forh-cyhalothrin (20 ppt at 10 DAA) and once for cypermethrin (100 ppt at 6 DAA) were detections made. For no sample were organophosphates observed. The absence of detections of organophosphates in runoff is a reflection of the short half-lives on leaves ( 4 day for methyl parathion) and in soil (< 10 days for the compounds studied). Pyrethroids can also show hal-lives on leaves of < 7 days, but these compounds exhibit considerably longer half-lives in soil (30 days for cypermethrin). No-detects of pyrethroids in runoff are due not only to time after application, but also to low sediment loads in runoff, since the lowwater solubilities ofthese compounds encourage association with sediment in runoff events.
Reciprocating subsurface-flow constructed wetlands for treating muncipal, industrial, and agricultural wastewater
Year: Authors: Behrends L.L., Rylant W.K.
Scientists at the Tennessee Valley Authority (TVA), have developed and are marketing an innovative wastewater treatment system based on reciprocatin subsurface-flow constructed wetlands. Reciprocation relates to patented improvements in the design and operation of paired subsurface-flow constructed wetlands, such that contiguous cells are filled and drained on a recurrent basis. This operating technique turns the entire wetland system into a fixed-film biological reactor, in which it is possible to have alternating aerobic and anaerobic zones. With the advent of recurrent reciprocation, it has become possible to manipulate the treatment systems biological structure and function by controlling such parameters as hydraulic retention time, frequency of reciprocation, reciprocation cycle time, depth of reciprocation, and size and composition of substrate. TVA’s improved constructed wetlands technology has been used successfully for treating municipal wastewater, high strength animal wastewater, and mixed wastewater streams containing acids, recalcitrant organics, deicers, heavy metals, explosives, and fertilizer nutrients. Recurrent reciprocation is a subsurface-flow process, therefore contaminated wastewater remains below the surface of the rock filter and reduces risk of direct exposure of personnel and wildlife to contaminants. Results from treatability studies and on-site demonstrations will be reviewed with respect to treatment efficacy and capital/operating costs.
Evaluation of Selected Commercial Flocculants for Removal of Organic and Inorganic Wood Preservatives from Process Water
Year: Authors: Shiohara K., Boarzjani A.
A large amount and variety of flocculants and coagulants are consumed by industries such as pulp and paper, and mining for wastewater treatments every year. Coagulants/flocculants also remove suspended substances from water at drinking water and municipal wastewater treatment facilities. Coagulants can destabilize fine, stable colloidal suspensions and induce precipitation. Flocculants induce individual particles to combine into larger sizes and speed up the settling out process. Inorganic materials like alum (aluminum sulfate), aluminum chloride, ferric sulfate and ferric chloride, and organic polymers such as polyamines and polyacrylamides have been widely utilized for such purposes (Ouellette 1996). While alum is still the most common coagulant/flocculant, the application of organic polymeric materials such as polyacrylamides is increasing. The main reason for this, in addition to treatment efficiency, is the large amount of sludges produced from the alum treatment process and the cost associated with it for further processing, such as dehydration and disposal of the sludges. Many studies have been done on the application, cost, and effectiveness of polymeric coagulants/flocculants in the past decade. Cathalifaud et al. (1993) reported that the suspension of kaolinite and ferric chloride could improve the coagulation-flocculation process, and de Velasquez et al. (1998) demonstrated 87% total suspended solid elimination by treating wastewater effluent from biological and chemical treatment systems with anionic and zwitterionic polymers in combination with metallic hydroxide. Boneva et al. (1994) and Bolto (1995) enhanced the treatment of wastewater with water-soluble polymers. New cationic flocculants of high charge densities and high molecular weights were introduced for the removal of oil and grease (Sang et al. 1995). To reduce the cost of treatment process, the application of synthetic organic polymers such as poly(diallyldimethylammonium chloride) was evaluated. Addition of this polymer reduced the usage of poly(aluminum chloride) in the treatment by 50% (Lee et al. 1998). Working on alternative procedures for the treatment of secondary effluents from the pulp and paper industry with solid residues of the process (e.g. dreg, grit, heavy ash) and activated carbon, an appreciable reduction of color, halogenated compounds, as well as significant savings on the amount of flocculants used was observed (Frizzo et al. 1996). The wood-preserving industry has a variety of chemicals such as creosote, pentachlorophenol (PCP) and chromated copper arsenate (CCA) in their treatment process. A large volume of contaminated wastewater containing these chemicals are generated that should be cleaned up. Creosote is a complex mixture of chemical constituents, including various polycyclic aromatic hydrocarbons (PAHs), phenolic compounds, and heterocyclic compounds. PCP is another common organic wood-preservative that is used in a 5-8% concentration in the pressure treatment of wood with number two diesel oil. Technical grade PCP also contains of the lower chlorinated phenols along with minute amounts of chlorobenzodioxins, chlorobenzofurans and chlorobenzenes. CCA is the most utilized waterborne wood-preservative for pressure treatment of wood, that resist attack by termites and fungi that cause decay. These chemical substances are introduced to the process wastewater from several different sources, such as pressure treatment, steaming of wood, vapor drying or oil seasoning. Treatment of such wastewater will be difficult because the wastewater contains various chemical compounds with different chemical and physical properties, which require certain conditions and chemicals for treatment. No major prior studies have been done on the removal efficiency of commercial flocculants/coagulants for the treatments of process water from wood treating facilities. This study evaluated different commercial polymeric flocculants that are currently being used by industry for the treatment of wood-preserving process wastewater containing a high concentration of oil & grease, polycyclic aromatic hydrocarbons (PAHs), pentachlorophenol (PCP), petroleum hydrocarbons, suspended solids, and traces of other inorganic chemicals.
Constructed wetlands, an alternative way of wastewater treatment
Year: Authors: Sistani K.R., Thicklin J.
Wetlands hold properties that make them unique among major ecosystems on the earth. Wetlands are an edge habitat located in areas between terrestrial and aquatic ecosystems. The idea that natural wetlands posses the ability to treat various wastewater discharges owing to their high rate of biological activities has been known for a long time. Constructed wetlands mimic natural wetlands and are designed to treat municipal, agricultural and industrial wastewater from point and nonpoint sources. As wastewater flow through the system, suspended solids, nutrients, and organic materials are filtered, absorbed, or degraded by plants and microorganisms living in wetland. In many areas, septic tank systems with field lines are commonly utilized to treat wastewater discharges from households orothersources. These septic systems usually fail when soil percolation rates are inadequate for field lines to work properly. A subsurface or surface flowconstructed wetland can provide further treatment of the effluent in these situations with minimal cost and maintenance. The objective of this study was to investigate the wastewater treatment efficacy and water quality improvement by six residential constructed wetland systems. The constructed wetlands are located in four Counties in north Alabama. Water samples were collected monthly for one year from inlet and outlet points of each cell within each system and analyzed forthe following water quality parameters: biochemical oxygen demand (BOD). chemical oxygen demand (COD), total suspended solid (TSS), phosphorus (P). ammonium nitrogen (NH,- N). nitrate nitrogen (NO,-N). total Kjeldahl nitrogen (TKN), and fecal coliform bacteria (FC). All the parameters analyzed were greatly reduced from influent to effluent points. The BOD, was reduced up to 85%. while FC bacteria reduction was as high as 99% at most of the sites. There was significant reduction in TSS (88%), TKN (74%). P (80%), and NH,-N (56%) in most of the constructed wetlands. Data also showed that treatment of septic tank effluent continued.
Crop residues reduce soil erosion
Year: Authors: McGregor K.C., Cullum R.F., Mutchler C.K.
Erosion of cropland is a severe problem. This article reviews some general soil erosion processes and emphasizes the role of crop residues in reducing soil erosion. Discussions include interrill erosion, rill erosion, surface seals, plant canopy, and tillage implements. Research results from laboratory experiments on soil erosion and field experiments help to appraise the effectiveness of crop residues in reducing cropland soil erosion. The article also discusses application of low cropping and management factor values for conservation tillage used in the revised universal soil loss equation (RUSLE).
Mercury in North Mississippi Lakes: A Growing Concern?
Year: Authors: Huggett D.B., Steevens J.A., Allgood J.C., Lutken C.B., Grace C.A., Benson W.H.
Contaminated food is the major route of exposure for humans to methyl mercury (USEPA 1997b). Currently in Mississippi, there are fish consumption advisories for mercury (mercury> 1.0 mg Hg/kg tissue) in seven water systems, including Enid Lake and the Yocona River below Enid Lake. In 1996, the Mississippi Department of Environmental Quality (MSDEQ) reported mean mercury concentrations in largemouth bass from Enid Lake of 1.07 mg Hg/kg tissue. MSDEQ data from Grenada and Sardis Lakes, which do not have fish consumption advisories, indicate that mean mercury concentrations in largemouth bass were on average 1.07 and 0.85 mg Hg/kg tissue, respectively. Not only do these data indicate that there may be a potential risk for people who consume these fish, but it is unknown if mercury contamination in these lakes results in adverse effects on survival, growth and reproduction of aquatic organisms. In addition, it is unclear as to why a health advisory has been issued for Enid Lake, while no health advisory has been issued for Sardis or Grenada Lakes. Based on available fish tissue data, the environmental fate and effects of mercury in Enid, Sardis, and Grenada Lakes merits attention. The objective of this study was to evaluate the parameters associated with mercury in fish tissue and compare three regional lakes in Mississippi. To address the main objective and issues described above, the specific aims of the study were to: 1) determine concentrations of mercury in sediment collected from Enid, Sardis, and Grenada Lakes; 2) determine concentrations of mercury in fish collected from Enid Lake; and 3) evaluate potential human hazard from fish consumption in area lakes.
Influence of Water Availability on Settlement Patterns
Year: Authors: Schmitz D.W., Wax C.L., Pote J.W.
While conducting a base line water resources inventory for the Red Hills generation facility and mine in Choctaw County, Mississippi, it was noticed that the development of water resources in the area appeared to fall into several discrete time categories, each associated wi1h identifiable technological innovations. It was also evident that each of the categories of technology provided certain constraints or opportunities for settlement in the region. Further investigation showed that, in fact, each progressively higher level of technology allowed greater opportunity for a less limiting arrangement of house sites and settlement distribution in the county. The purpose of this study is to document the different levels of water resource technology that were used to support humans as they occupied the land of this region from prehistoric times to the present.
Effects of Hurricane Georges on the Central Gulf of Mexico Coast
Year: Authors: Turnipseed D.P., Winters K.E.
In keeping with the mission of the U.S. Geological Survey (USGS) to provide the Nation with reliable, impartial information to describe and understand the Earth, crews from the Water Resources Division (USGS-WRD), in cooperation with many State and local agencies and the U.S. Army Corps of Engineers (USACE), Mobile District, began the hazardous task of measuring water levels and flood flows and surveying storm surge on September 28, soon after landfall of Georges. National Mapping Division (USGS-NMD) personnel worked closely with emergency management agencies to update and maintain the inventory of cartographic products necessary to support emergency management operations. These cartographic products were available in Louisiana, Mississippi, and Florida during the Hurricane Georges disaster. Additional support was provided to the American Red Cross with the distribution of maps in the Central Gulf Coast area. Crews from the Geologic (USGS-GO) and Biological Resources (USGS-BRD) Divisions mobilized immediately after the storm to obtain aerial photography of the barrier islands in the Central Gulf Coast to assess coastal erosion and habitat destruction. This report presents selected provisional data on headwater flooding, storm surge, beach erosion, and habitat destruction caused by Hurricane Georges along the Central Gulf Coast.
Application of WASP5 for Water Quality Modeling of Black Bay of Biloxi
Year: Authors: Shindala A., Zitta V.L., Hashim N.B.
The development of hydrodynamic and water quality models for Back Bay of Biloxi was initiated in response to an increasing need for a comprehensive water qualrty model that will facilitate decision-making in the overall management activities of the Bay estuarine system, including assessment of existing water quality, estimation of waste assimilative capacity under various conditions and seasonal variations, and analysis of the effect of waste discharge into the Bay. The Water Quality Analysis Simulation Program-5 (WASP5) was chosen for application to Back Bay of Biloxi (Ambrose et a!. 1993). This model is capable of interpreting and predicting water quality responses to natural phenomena and man-made pollution. Due to the nutrient enrichment and eutrophication problems in the Back Bay of Biloxi, intermediate eutrophication kinetics, which is complexity level 5 in EUTRO5 is utilized. WASPS system consists of three stand-alone computer programs, DYNHYD5, EUTRO5, and TOXIS that can be run in conjunction or separately. The hydrodynamics program, DYNHYD5, simulates the movement of water; while the water quality program, EUTRO5, simulates the movement and interaction of pollutants within the water. The study area is located along the Mississippi Gulf Coast and is adjacent to Jackson and Hancock Counties (Figure 1). Also included in the study area are the metropolitan areas of Biloxi, Gulfport, Ocean Springs, and D’Iberville. The initial model calibration was accomplished utilizing historical data collected during the periods of July 28-August 2,1972, and June 14-16, 1977 (Shindala et al. 1996). Final model calibration was performed utilizing a set of field data acquired on the Back Bay of Biloxi, during September 12-21, 1994. Model verification was conducted against another set of field data taken in the Bay, during April 25-May 2, 1995. This paper presents the details of the implementation of the water quality modeling framework together with results of the water quality calibration/verification effort. Details of the hydrodynamic calibration effort are discussed in the Completion Report (Shindala et al. 1996) and reference (Zilla et al. 1999).
Elevation of Soil Additives and Microorganisms on the Leaching Potential and Removal of Crude Oil and Pentachlorophenol from Soil
Year: Authors: Borazjani A., Schrader E.L., Diehl S.V., Hurt K.
Land treatment has been accepted as a viable soil remediation technology for many classes of organic pollutants. A significant body of both laboratory and field experimental work has demonstrated the biodegradability of petroleum wastes and chlorinated organics, as well as the environmental safety of this process (Bossert et al. 1984; Lamar and Dietrich 1990; McGinnis et al. 1991). However, the physical properties of soil can impede the biological destruction of contaminants. Successful soil remediation depends on the interaction of contaminants with microorganisms living within the soil. Low permeability soils with strong sorption characteristics usually exhibit slower degradation rates. Additives can be applied to the soil to maximize the interaction between microorganisms, thus increasing degradation rates. However, these additives may also affect contaminant migration by accelerating or hindering the mobility of target chemicals in the soil. The amount and concentration of organic pollutants that leach out of contaminated sites are receiving considerable attention. Increased awareness and concems are primarily due to environmental mandates and regulations to reduce the impact of the contaminants on rivers, lakes, streams, and oceans. The Environmental Protection Agency (EPA) has adopted a TCLP test for estimating the leaching potential of organic and inorganic pollutants. TCLP measures a constituent’s potential to contaminate groundwater. The rule defers regulation of certain petroleum-contaminated wastes, such as underground storage tank sites, and exempts polychlorinated biphenyls (PCBs) waste already regulated under the Toxic Control Substance Act. The overall goal of this project was to evaluate the use of fungi and different soil additives on bioremoval and the leaching potential of two different crude oils and pentachlorophenol (PCP).
Case History of a High Hazard Dam
Year: Authors: Clevenger C.E., Meadows M.
Section 51-3-51 of the Mississippi code of 1972, as amended, states that anyone wishing to construct, repair, or modify a dam in the State of Mississippi must, prior to construction thereof, make application for and receive written authorization from the Commission on Environmental Quality. Section VII of the Regulations promulgated by the Commission defines a High Hazard dam as one that should it fail, there is the possibility of loss of life and/or major property damage downstream. Vice Lake Dam is a high hazard dam located in Lauderdale County, Mississippi, South of Meridian. The dam is 1670 feet long, 53 feet high, impounds a 178 surface acre lake at normal pool; it originally had a riser and conduit for the principal spillway and an earthen grass lined emergency spillway. The dam is classified as high hazard because of several houses downstream that could in danger should the dam fail.
Mutagenic and Lethal Effect of Surface Water in Mississippi’s Rivers and Lakes
Year: Authors: Yang W.H., Yang J.R.
The aquatic systems in the world have been polluted in various degrees with toxic organic and inorganic chemicals following years of civil activity, industrialization, war, and agrichemical usage (Callahan et al. 1979; Edward et al. 1979; Bakre et a1.1990, Rehana et al. 1996). Civil activities along the river have released huge amounts of waste into the river. Old pollutants resurfaced from increased combustion of fossil fuels for transportation, heating, and power generation. Agrichemicals and war industries added varieties of new xenobiotics including insecticides to the environments. Our previous study indicated that lower stream of Mississippi River had been polluted with various concentrations of selenium and mercury (Yang et al. 1994). Our current study intends to focus further on the genotoxic effect of pollutants in the surface waters of rivers and lakes in Mississippi. The first river to be examined in Mississippi is the Mississippi River, one of the major rivers going through most active industrial, agricultural, and populated areas in the U.S.A. The second river, Pearl River, is a local river of Mississippi going through less industrialized rural area. The third river, Tombigbee Waterway is important for transportation for Ohio, Tennessee, Mississippi, Alabama, and Gulf of Mexico. Most of the reservoirs or lakes in Mississippi are located in the rural areas of the state. Study of those rivers and lakes with different backgrounds and functions will help our better understanding of problems in our aquatic environments. This study intends to assay water samples at three sequentially diluted levels so that best fit regression and the correlation factor (or coefficient) of data can be obtained. The sign and numberofthe correlation factor is used for assessing the phase difference in the genotoxicity. And the number of bacterial colony formation will be evaluated proportionally to the degree of toxicity in the mutagenic phase and inversely to that in the lethal phase.
Calibration of WASP5 for Hydrodynamic Transport in Back Bay of Biloxi
Year: Authors: Zitta V.L., Shindala A., Hashim N.B.
The development of hydrodynamic and water quality models for Back Bay of Biloxi was initiated in response to an increasing need for a comprehensive water quality model that will facilitate decision-making in the overall management activities of the Bay estuarine system, including assessment of existing water quality, estimation of waste assimilative capacity under various conditions and seasonal variations, and analysis of the effect of waste discharge into the Bay. The Water Quality Analysis Simulation Program-5 (WASP5) was chosen for application to Back Bay of Biloxi (Ambrose et al. 1993). This model is capable of interpreting and predicting water quality responses to natural phenomena and man-made pollution. WASP5 system consists of three stand-alone computer programs, DYNHYD5, EUTR05, and TOXI5 that can be run conjunction or separately. The hydrodynamics program, DYNHYD5 simulates the movement of water, while the water quality program, EUTR05, simulates the movement and interaction of pollutants within the water.
Occurrence of Pesticides in Rain and Air in Urban and Agricultural Areas of Mississippi, April-September 1995
Year: Authors: Coupe R.H., Manning M.A., Foreman W.T., Goolsby D.A., Majewski M.S.
In April of 1995, the U.S. Geological Survey began a study to determine the occurrence and temporal distribution of 49 pesticides and pesticide metabolites in air and rain samples from an urban and agricultural sampling site in Mississippi. The study was a joint effort between the National Water Quality Assessment and the Toxics Substances Programs and was part of a larger study examining the occurrence and temporal distribution of pesticides in air and rain in the Mississippi River Basin. Concurrent high-volume air and wet-only deposition samples were collected weekly. The air samplers consisted of a glass-fiber filter to collect particles and tandem polyurethane foam plugs to collect gas-phase pesticides. Every rain and air sample collected from the urban and agricultural site had detectable levels of multiple pesticides. The magnitude of the total concentration was 5 to 10 times higher at the agricultural site as compared to the urban site. The pesticide with the highest concentration in rain at both sites was methyl parathion. The pesticide with the highest concentration in the air samples from the agricultural site was also methyl parathion, but from the urban site the highest concentration was diazinon followed closely by chlorpyrifos. A metabolite of p.p-DDT, p.p-DDE, was detected in every sample from the agricultural site and in more than half of the air samples from the urban site more than two decades since DDT was banned from use in the United States.
Herbicides and Their Metabolites in the Surface Waters of the Mississippi River Alluvial Plain
Year: Authors: Coupe R.H., Thurman E.M.
The broad flat Mississippi River Alluvial Plain, located on both sides of the Mississippi River (predominately in Arkansas, Louisiana, Mississippi, and Missouri) is one of the most agriculturally productive areas in the United States. The major crops grown in this area include com, cotton, rice, and soybeans. Although pesticides are used in row crop production throughout the United States to improve yields and protect crops, pesticide use in the Mississippi River Alluvial Plain exceeds that of most other parts of the United States. The greater use of pesticides is largely because of the intense weed and insect pressure in the humid southeastern United States and the types of crops, such as cotton, that are slow growing and very susceptible to yield loss. There is concern that this heavy use of pesticides may contaminate surface waters. In addition to the parent compounds, metabolites of the pesticides may also contaminate surface waters. The toxicological significance ofthe presence of these metabolites in surface water is not usually known because most studies focus on the toxicity of the parent compounds. During the 1996 and 1997 growing season, surface-water samples were collected from streams in the Mississippi River Alluvial Plain and analyzed for selected herbicides and metabolites. The herbicides for which the surface-water samples were analyzed include atrazine (6-chloro-N-ethyl-N- (1-methylethyl)-1,3,5-triazine-2, 4-diamine), cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropanenitrile), fluometuron (N,N-dimethylN-[ 3-(trifluoromethyl)phenyl]urea), norflurazon (4-chloro-5-(methylamino)-2-(3-(trifluoromethyl)phenyl)-3(2H)pyridazinone), and propanil (N-(3,4-dichlorophyenyl)propanamide), some of the most heavily used herbicides in the Alluvial Plain. In addition, the surface-water samples were analyzed for at least one metabolite for each herbicide. The results indicate that for some herbicides, such as propanil, the parent compound is almost never detected above the reporting level in surface water; however, 3,4-dichloroaniline, a metabolite of propanil, was detected frequently throughout the growing season after the application of propanil. The concentration of 3,4-dicholoaniline did not exceed 1.0 ug/L in any sample. Other herbicides such as atrazine and fluometuron were detected frequently with a range in concentrations from 1 to 10 ug/L, and their metabolites were also detected frequently, but at lower concentrations ranging from 0.05 to 1 ug/L. Metabolites represent about 10 percent of the total concentration in samples collected at the beginning of the growing season, but become proportionally more significant later in the season as the parent compound dissipates and degrades. Metabolites represented as much as 50 percent of the total concentration at the end of the growing season.
Analysis of Selected Herbicide Metabolites in Surface and Ground Water of the United States
Year: Authors: Scribner E.A., Thurman E.M., Zimmerman L.R.
In 1987, a laboratory for organic geochemistry research was established at the USGS in Lawrence, Kansas. Since that time, analytical methods have been and continue to be developed to measure metabolite concentrations from three major classes of herbicides-triazine, chloroacetanilide, and phenylurea. From studies of degradation, fate, and transport of herbicides and their metabolites in soil and aquatic environments, numerous journal articles, book chapters, and USGS reports have been published. The principal purpose of this paper is to list the analytical methods that have been developed to measure herbicide metabolites in surface and ground water. Listings of herbicide and metabolite surveys that have been conducted through the USGS laboratory in Lawrence also are summarized. Brief descriptions and illustrations depicting the degradation pathways forthe parent herbicides also are presented.
Assessment of Nutrient Trends and Loads for the Mobile River Basin
Year: Authors: Harned D., Atkins J.B.
U.S. Geological Survey (USGS) surface-water sampling sites in the Mobile River Basin were reviewed for available nutrient data for the period 1970-97. Sites having sufficient nutrient data were evaluated for longterm trends in nutrient concentrations and nutrient transport was calculated for selected basins. The effort was undertaken as part of the National Water-Quality Assessment (NAWQA) Program (Gilliom et al. 1995). USGS sampling sites having periods of continuous streamflow and nutrient data from the period 1970-97 were examined for long-term trends with the Seasonal Kendall trend test. Trends and loads were estimated for total nitrogen at 14 sites and for total phosphorus at 15 sites (Figure 1 and Table 1). The Seasonal Kendall trend test adjusts for seasonal variability using nutrient concentrations adjusted for the effects of streamflow with residuals from LOWESS (Locally Weighted Sum of Squares) smoothed curves. Trends were also determined for sites without continuous data using multivariate regression analysis.
The Mississippi Delta Management Systems Evaluation Areas Project - Current Status and Preliminary Findings
Year: Authors: Rebich R.A., Dabney S.M., Pote J.W.
The data base generated from this project will be useful to landowners and management agencies in making sound decisions regarding agricultural nonpoint source pollution and implementation of BMPs. The BMPs are evaluated for their economic and environmental value at the farm and watershed scales. In addition, educational and public awareness programs associated with the project help to communicate the research findings and BMP information which will ultimately help improve water quality in the Delta region. The purpose of this paper is to present the current status and preliminary findings of the research activities of the MDMSEA project.
Water Quality Model for Big Sunflower River
Year: Authors: Hashim N.B., Shindala A., Zitta V.L.
The development of hydrodynamic and water quality models for Big Sunflower was initiated in response to an increasing need for a comprehensive water quality model that will facilitate decision-making in the overall management activities of the river system, including assessment of existing water quality, estimation of waste assimilative capacity under various conditions and seasonal variations, and analysis of the effect of waste discharge into the Big Sunflower River. The Water Quality Analysis Simulation Program-5 (WASP5) was chosen for application to Big Sunflower River (Ambrose et al. 1993). This model is capable of interpreting and predicting water quality responses to natural phenomena and man-made pollution. WASP5 system consists of three stand-alone computer programs, DYNHYD5, EUTRO5, and TOXI5 that can be run in conjunction or separately. The hydrodynamics program, DYNHYD5 simulates the movement of water, while the water quality program, EUTRO5, simulates the movement and interaction of pollutants within the water. The study area includes the Big Sunflower River, its northem and southern ends, and tributaries flowing into this river. The Big Sunflower River lies almost entirely within Sharkey, Sunflower, Washington, Humphreys, Bolivar, and Coahoma counties (Figure 1). The major metropolitan areas in this study are comprised of Clarksdale, Sunflower, and Indianola. The initial model calibration was accomplished utilizing historical data collected during the period of July 30-August 1, 1974 (Shindala et al. 1997). Final model calibration was performed utilizing a set of field data acquired on the Big Sunflower River during October 19-23, 1997. This paper presents the details of the implementation of the hydrodynamic and water quality modeling framework together with results of the hydrodynamic and water quality calibration efforts.
An Introduction to Innovative Chemical Oxidation Techniques for Treatment of Contaminated Waters
Year: Authors: Zappi M.E., Hernandez R., Kuo C.H., Qasim M., Fleming B., Francingues N.
Among the many contaminants threatening groundwater resources or within industrial wastewaters are chlorinated solvents, phenolics, pesticides, chemical weapons, explosives, and fuel derived aromatics. Treatment processes that have been used in the past for remediation of these groundwaters are activated carbon and air stripping. Unfortunately, both processes rely on a solution phase change mechanisms (i.e. transport of the contaminant from water to gas [stripping] or solid [carbon]) and not on the on-site destruction of the contaminants. Additionally, with an increased awareness of air pollution, air stripping is now rarely implemented without some form of air stream treatment, such as activated carbon adsorption, which greatly impacts the economics of this process. As water standards are lowered, both of these technologies become much less efficient in terms of cost and treatment effectiveness (Zappi 1998). Therefore, the development and evaluation of potentially more cost effective and improved performing processes, such as chemical oxidation, is advantageous to interested parties facing either site remediation or wastewater treatment.
Detection of Persistent Organic Pollutants in the Mississippi Delta Using Semipermeable Membrane Devices
Year: Authors: Zimmerman L.R., Thurman E.M., Bastian K.C.
POPs are hazardous chemicals, with moderate to low volatility, that resist degradation and tend to accumulate in living tissues. Their persistence in various media facilitates their transport over long distances to remote regions where they have never been used. They have been found to present risks to human health and the environment in polar and other regions (Wahlstrom 1997). In February 1997, a United Nations Environmental Program Goveming Council Decision identified 12 POPs (aldrin, chlordane, DDT, dieldrin, dioxins, endrin, furans, heptachlor, hexachlorobenzene, mirex, polychlorinated biphenyls, and toxaphene) for which intemational action was deemed necessary to protect human health and the environment. Because POPs are present at such low concentrations in the aquatic environment, it is difficult to detect them with conventional chemical analysis, but they still may be important in the environment because they can accumulate in animal fat. Analyzing POPs in water samples is cumbersome because their low solubilities would require large sample volumes to detect concentrations at the levels common in the environment. Fish tissue has been the common method for analysis, but a biological sampling must consider additional complications such as analyte metabolism, disease, predation, migration, or the possible introduction of a foreign species.
Characterizing the Chemical Mixture Interactions of Chlorpyrifos, Dieldrin, and Methyl Mercury
Year: Authors: Steevens J.A., Benson W.H.
The main objective of the current study was to assess the chemical mixture interactions of structurally dissimilar chemicals with similar toxicological mechanisms. Three model compounds chlorpyrifos, dieldrin, and methyl mercury, which represent environmentally relevant chemical contaminants were selected due to their persistence, mode of action, and occurrence at concentrations capable of producing adverse toxicological effects. All three bioaccumulative chemicals are considered neurotoxicants, which elicit their effects through specific independent mechanisms. Although the toxicity of the individual toxicants is understood, very little is known regarding the binary interactions of these chemicals. Chlorpyrifos, an organophosphate insecticide, is widely used in the United States with more than 21 million pounds applied to crop land each year (USGS 1998). Chlorpyrifos exerts its toxicity by inhibiting acetylcholinesterase, an important enzyme which modulates the concentration of the neurotransmitter acetylcholine (Tomlin 1994). Dieldrin is an organochlorine insecticide used from the 1950s to the late 1980s to control agricultural pests and termites. In 1990, the U.S. EPA banned production, although its use on agricultural crops and buildings was already limited. Dieldrin is no longer used in the U.S.; however, dieldrin and similar organochlorines continue to persist in the environment due to their long half-life (2 to 10 years) (Mongomery 1993; Loganathan 1994). Dieldrin exerts its toxicity by binding to the GABA. receptor and blocking the flux of chloride ion which normally acts to inhibit neural transmission (Narahashi 1995). Methyl mercury was selected as a model organic metal toxicant primarily due to its ubiquitous occurrence and neurotoxic effects, as well as its ability to bioaccumulate. Approximately 4,500 metric tons of mercury are released into the environment each year by human activities such as combustion of fossil fuels and other industrial releases (Lindquist et al. 1991). Methyl mercury is persistent in sediments and has been shown to bioaccumulate and biomagnify in fish and invertebrates (Suedel and Rodgers 1994). Methyl mercury can actively accumulate in an organism through an L-amino acid transporter and exerts its toxicity by depleting cellular stores of the antioxidant glutathione or by inducing oxidative stress (Mokrzan et al. 1995).
Evaluation of Subsurface Drainage for Sugarcane Lands and its Effects on Soil Trafficability
Year: Authors: Fouss J.L., Kornecki T.S.
This research is intended to show the benefits of subsurface drainage and water table control to improve water quality and trafficability for sugarcane lands. This research will also be used to develop criteria for predicting both water quality factors and trafficability through modeling and simulation. The field project will serve as a demonstration site to show Louisiana’s sugarcane growers and industry officials the benefits of subsurface drainage and/or water table control for increasing potential sugar yields and the longevity of the cane stand, and for improving trafficability for planting, cultivating, and harvesting field operations. A major thrust area of this research will be to show potential environmental benefits such as water quality improvements that may be achieved through managed (controlled) runoff and subsurface drainage.
Assessing Water Quality in the Mobile River Basin
Year: Authors: Atkins J.B.
In 1991, the U.S. Geological Survey (USGS) began implementation of the National Water-Quality Assessment (NAWQA) Program. The three major objectives of the NAWQA Program are to: (1) provide a consistent description of current water-quality conditions for a large part of the Nation’s ground- and surface-water resources, (2) describe howwaterquality is changing with time, and (3) explain the natural and human factors that may affect observed water-quality. Consistent data collection and analysis methods throughout 59 of the Nation’s most important river and aquifer systems provide uniform and comparable information to address water-quality concems at local, regional, and national scales. The Mobile River Basin NAWQA study design incorporates surface-water, ecological, and ground-water studies to help understand water-quality conditions and issues affecting the Mobile River Basin (Figure 1). Major components of these studies include analysis of surface and ground water for selected chemical constituents, measured physical properties, and biological surveys of aquatic organisms and habitats. The surface-water component of the study consists of nine surface-water sites throughout the Mobile River Basin. Water-quality samples will be collected at these sites on a monthly basis and during selected storm events for about 2 years and analyzed for major ions, nutrients, and suspended sediment. In addition, water quality samples will be collected on a weekly basis during the growing season and analyzed for pesticides at two of those sites. Ecological studies will be conducted at all sites to describe relations between water quality and aquatic biological communities. Components of the ecological studies include aquatic and riparian habitat assessments and annual surveys of fish, algal, and benthic invertebrate communities. The ground-water component consists of sampling about 30 shallow domestic wells in the Fall Line Hills District of the Coastal Plain Province. Ground-water samples from these wells will be analyzed for major ions, nutrients, pesticides, trace elements, bacteria, and volatile organic compounds. Additionally, about 30 shallow wells will be drilled in agricultural areas of the Alluvial Floodplain District of the Coastal Plain and in the urban area of Montgomery, Alabama. Groundwater samples from these wells will be analyzed for major ions, nutrients, and pesticides.
Assessing the Effect of Photoproducts of 2,4,6-Trinitrotoluene (TNT) on Microbial Assemblages in Natural Aquatic Environment
Year: Authors: Hwang H.M., Slaughter L., Cook S., Wiggins S.
2,4,6-Trinitrotoluene (TNT) is a nitro-aromatic compound that has been widely used by the military in the production of shells, bombs, and grenades. Wastewater from munitions plants was discarded on the ground or in lagoons, which lead to an extensive contamination of the soil, groundwater, rivers, and lakes (Boopathy et al. 1994). This brought about serious concems as to the environmental fate of TNT and its metabolites because of worry that it would find its way into the food chain (Harvey 1990). Concem about the chemical was compounded because of its toxicity and recalcitrance to biodegradation (Funk, Crawford, and Crawford 1996). The disposal of large quantities of TNT in an environmentally acceptable manner poses serious difficulties. One past manner of disposal included the dumping of obsolete munitions in the sea. Open buming and detonation were also used, but were deemed ineffective because they added particulates, N02, and other products to the already polluted air (Yinon 1990). Researchers began to look at other methods for the remediation of the chemical including photolysis and microbial degradation. Both of these processes have been shown to be effective degrading processes affecting selected nitro-aromatic pollutants in aquatic environments (Hwang et al. 1986). The use of microbial bioassays has been widely used, based on the assumption that microorganisms can act as surrogates for higher organisms in the environment. In addition, microbial bioassays are desirable because they are relatively simple, inexpensive, and swift. Furthermore, the use of sensitizers has been shown, in some cases, to enhance the photolysis rate of organic compounds (Halmann 1996). In this study, the effects of TNT and its photoproducts on microbial activity were analyzed with measurements of viable bacterial numbers and bacterial mineralization of glucose. In addition, the effects of the sensitizer riboflavin on TNT were also studied. The photolysis of TNT in direct sunlight was studied using the HPLC to measure the final concentration of the chemical after exposure.
MSEA and STRIDE: A Cooperative Experience in Science Education
Year: Authors: Thibaudeau G., Beamon H., Pote J., Harpole S., Bailey J.
The primary objective of this project is to train teachers and students in research data collection and analysis techniques through real scientific research experiences. Through their experiences, teachers understand the role of research in the classroom and enhance their scientific content knowledge. Students in upper middle schools in the Mississippi Delta receive meaningful interdisciplinary research experience and learn how to design and evaluate best management practices for improving water quality and ecology in the Mississippi Delta. Participants increase awareness of environmental and management issues relating to the Mississippi Delta rivers and lakes. STRIDE participants also increase their awareness of careers in science and engineering.
Seasonal Release of Estrogenically Active Municipal Wastewater: An Assessment Utilizing In Situ Biomarkers
Year: Authors: Tilton F., Schlenk D.K., Benson W.H.
To date, estrogenically active wastewater has been reported to arise from several WWTPs in the U.S. and U.K. as demonstrated by studies utilizing caged and feral fish populations downstream of WWTP outfalls (Purdom 1994; Folmar 1996). The majority of studies have focused on the identification of estrogenically active wastewater downstream of WWTPs and do not reflect the seasonal variation that may exist. The focus of the present investigation was to identify and characterize the production of estrogenically active wastewater from two activated sludge treatment facilities in Lafayette County, Mississippi. U.S.A. over several seasons. Wastewater was screened, on a seasonal basis, utilizing a caged fish model placed within the effluent of two activated sludge treatment facilities for 21 days. These data demonstrate the seasonal release of estrogenically active wastewater and suggest that the release of this wastewater is dependent on the metabolic efficacy of the microbial populations within the WWTP.
Effect of Plot Size on Runoff of Herbicides and Suspended Sediment
Year: Authors: Southwick L.M., Fouss J.L., Bengtson R.L.
In this paper we compare/contrast runoff of herbicides and suspended sediment to test for trends that might be due to the differences in plot sizes in our field work. We look at results for atrazine and metolachlor in runoff from 4.4-ha plots in 1987 (Southwick et al. 1990b) and from 0.21-ha plots in 1995 (Southwick et al. 1997a) and 1996. We also compare/contrast runoff of trifluralin from the 4.4-ha plots in 1992 (Southwick et al. 1997b) with results for pendimethalin from the 0.21-ha plots in 1996. We discuss the suspended sediment in runoff in these studies (Southwick et al. 1997a; Bengtson et al. 1998). We consider here results only from plots without subsurface drains. In our comparisons we also assess the size of an "elemental area" (Huggins and Burney 1982) in these field studies.
Relationship Between Surface Water Sediment Concentration, Total Phosphorus, and Total Kjeldahl Nitrogen in Mississippi Delta Streams
Year: Authors: Pennington K.
Surface water quality continues to be a topic of concern for state governments trying to comply with federal mandates for clean water. The U.S. Environmental Protection Agency (EPA) has made significant progress in developing its procedures for mandating control of nonpoint sources of pollution through their Total Maximum Daily Load (TMDL) program (40 C.F.R.). Mississippi Departments of Environmental Quality (MSDEQ) is trying to better define the water quality problems in the state (MSDEQ 1999). Information in this paper could help to focus monitoring and TMDL development efforts. USDA Natural Resource Conservation Service (NRCS) began a Delta wide study in 1992 to find alternative water supplies for irrigation and environmental quality maintenance during low flow periods. Existing Delta surface water quality needed to be monitored in order to determine how best to address supply and quality concerns. NRCS has conducted monthly surface water quality sampling on the major interior Delta streams starting in 1993 with Deer Creek and expanding by 1994 to the Sunflower River, Bogue Phalia and Quiver River. Data were gathered through 1997 from a total of 22 sites for varying lengths of time (1996 Pennington; USDA NRCS 1999). Examination of this information provides a good picture of seasonal variations in water quality parameters and provides a basis for prioritizing these concerns for improvement through conservation based land use. The patterns followed by sediments and nutrients in these waters were indicative of the nature and seasonality of these parameters. Total phosphorus, total kjeldahl nitrogen, total solids, total suspended solids and turbidity were chosen for further study. About 3 million of the Delta’s 4 million acres are in agricultural production. Agriculture is essential to the economic viability of this part of our state. However, farming in the Mississippi Delta potentially moves more soil than any other activity elsewhere in the state. The opportunities for sediment and nutrient control are plentiful. NRCS has been developing management practices for control of soil erosion and sediment transport for over 60 years. The technology is available to address our environmental concerns. The current challenge is to find the funding and implement these practices in sufficient numbers in strategically located areas using watershed planning to achieve the water resource goals that will be mandated under the TMDL program through the MSDEQ.
Shallow Groundwater Resources of the Proposed Red Hills Facility and Mine Area
Year: Authors: Charlton J.E., Schmitz D.W.
A study was conducted in order to gather information on the nature of the water resources in the study area in Choctaw County, Mississippi, prior to the proposed development of a lignite mine within the study area. Within this area exist domestic and public supply wells, natural springs, and ponds. Samples taken from ponds, springs, and wells were collected for chemical analysis. On-sight measurements of pH, temperature, specific conductivity, and color were recorded at surface impoundments, springs, and wells. Water level measurements were taken in all accessible wells. Spring flow rates were estimated from velocity of the flow and cross sectional area. Shallow groundwater data was provided by local citizenry, well measurements and well water sample collection. Springs that could be located using topographic maps, aerial photographs, and information from the population of the study area were sampled and tested. Water quantity has been sufficient to support area population. The only concems with respect to water quality were eight wells and thirty-six springs that exhibited iron levels above potable drinking water standards.
Adaptive Nature of Waterborne Microbial Pothogens in Cold Temperatures
Year: Authors: Caroll J.W., Bej A.K.
Changes in the environmental physico-chemical parameters may have profound effects on the physiology of the microorganisms leading them to adaptation to the altered environment for their survival (Colwell et al. 1977; Miller et al. 1984; Singleton et al.; 1982). The adaptation to the changing environment in these microorganisms could be displayed through the change in the cell morphologies, cellular protein syntheses and overall growth pattems (Colwell and Huq 1994). In many occasions these microbial cells could enter into dormant state by compromising their culturability on microbiological media (Colwell and Huq 1994; Oliver 1993). To date, suboptimal growth temperatures or nutrient deprivation have been identified as the two most important environmental factors that trigger cellular processes in these microorganism to enter into dormant state (Colwell and Huq 1994; Oliver 1993). Some of the microbial pathogens such as Escherichia coli (Xu et al. 1982), Legionella pneumophila (Hussong et aI.1987), Salmonella enteritidis (Roszak et al. 1984) and Vibrio vulnificus (Oliver 1993) have been shown to enter into dormant state and remain non-culturable on various microbiological media. Also, it has been reported that a waterborne microbial pathogen, V. cholerae, disappears from their water habitat during the winter months and are detected during summer months (Adikari 1975; Uchiyama 1998; Ravel et al. 1995). V. cholerae is a Gram negative bacterium with distinct ’comma" shaped appearance and this pathogen is known to cause cholera in humans primarily through the consumption of contaminated drinking or potable waters. This pathogen is endemic to many of the developing countries including South America and Asia and causes cholera outbreaks often in an epidemic form (Kaysner and Hill 1994). In the United States, although the number of cases of cholera has been extremely low during the past decade; however, the Gulf of Mexico is considered to be the reservoir for this pathogen (Colwell and Huq 1994; Kaysner and Hill 1994). Therefore, the Federal Govemment guideline requires routine monitoring seafood and shellfish for the presence of this pathogen before shipped to the restaurants for human consumption (Bej et al. 1996, 1997). In this report, we have investigated the effects of the suboptimal growth temperatures in this waterbome microbial pathogen, Vibrio cholerae, by studying their viability on a microbiological medium and changes in their cellular morphologies.
Pearl River Flood-Tracking Network
Year: Authors: Plunkett M.L.
The U. S. Geological Survey, in cooperation with the Mississippi Emergency Management Agency. Pearl River Basin Development District. Pearl River Valley Water Supply District, City of Jackson, and the National Weather Service, is developing improved flood-tracking capabilities for the Pearl River Basin. The purpose of the Pearl River Flood-Tracking Network is to educate the public on the process and value of monitoring a flood and to provide fast and reliable access to critical information on flood conditions to the public and agencies involved in flood-response efforts. When fully implemented, the flood-tracking network will provide: Better access to satellite telemetry of river-stage data for about 20 sites in the basin; A published Flood-Tracking Chart for distribution to the public; Streamlined Internet access to current river conditions and flood forecasts; Internet access to an interactive version of the Flood-Tracking Chart; Timed fax distribution of current river conditions and flood forecasts to key agencies and news media; and Phone modem access to U. S. Geological Survey databases for key agencies.
Estimating Crop Water Use with Satellite Imagery in the Mississippi Delta
Year: Authors: Stiles M., Pennington D.
A computer groundwater flow model of the alluvial aquifer is an important and necessary tool for this regional water use planning process. The U.S. Geological Survey (USGS) has agreed to assist in the planning for the development of alternative water supplies by developing the computer model of the alluvial aquifer in a cooperative project with YMD, NRCS, and the Office of Land and Water Resources (OLWR). One component needed for the development of the model is the best possible spatial and temporal estimates of water withdrawals from the aquifer. In the past, YMD has provided this data using data derived from a relational database management system (Stiles and Pennington 1996). While this provided for adequate estimates to begin the modeling process, the main flaw was an inability to accurately locate crops. This inability to specify crop location introduced a significant error in the spatial element of water use calculations. With the availability of inexpensive satellite imagery and PC platform image processing software. YMD intends to establish more accurate crop type designations to be used in water use estimates.
Using GPS in Ground Truthing for Supervised Crop Classification
Year: Authors: Stiles M., Brophy K.
The Yazoo Mississippi Delta Joint Water Management District (YMD) currently uses various technologies in data management. These include Geographic Information Systems (GIS), Global Positioning Systems (GPS) and Image Processing. As part of a new project to classify satellite imagery into crop types for water use calculations, (Stiles and Pennington 1998) various methodologies were used for gathering information used in the classification process. This paper documents these procedures. Dates for gathering information in the field were coincided with the dates the satellite was overhead. Two primary forms of data were gathered. Polygons in the form of field boundaries and points were cast out into the field. Information on the field boundaries was gathered using a Trimble PR0-XR Real Time Differential GPS connected via cable to a Gateway Notebook Computer running Maplnfo (GIS) and Blue Marble Graphics Geo Tracker software. This method allowed for a continual display of the current location point overlaid onto background information including roads, streams, county boundaries, and previously digitized irrigated field boundaries. When a site was selected, a polygon was drawn on-screen estimating the field boundary. See Figure 1, Ground Truth Polygons. In addition. several attributes were recorded. These included: Site ID Crop Type Canopy Cover Percentage Weed Cover Percentage Weed Type Field Tillage Condition Field Wetness Soil Color An advantage of this method was that no data transfer was required after gathering. When a user left the site, the data was already in the GIS (MapInfo). The polygons were then displayed by crop type in an ER Mapper. An ER Mapper is an image processing application used in the classifying of satellite imagery. New polygons were drawn to reflect more accurate boundary information because field edges could easily be interpreted from the satellite imagery.
Sediment Management at Water Intakes
Year: Authors: Barkdoll B.D.
The primary motivation for this study is the need to address the common problem of sediment ingestion with water flow into lateral intakes adjoining alluvial-sediment rivers. This paper is part of a larger study (Barkdoll 1997 and Barkdoll et al. 1997) that examines the flow and ingestion of bed sediment at lateral intakes from loose-bed channels and it evaluates measures for controlling sediment ingestion. The findings of the study apply to lateral intakes in general. However, they are aimed specifically at pump-intake intakes, such as those used for power generation stations. The geometty and outflow conditions of pump-intake intakes make them particularly susceptible to blockage and other problems caused by excessive sediment deposition.
Application for Arbitrarily Primed Polymerase Chain Reaction (AP-PCR) for the Detection of Vibrio parahaemolyticus in Shellfish
Year: Authors: Bej A.K., Bashar F., Jones D.D.
The AP-PCR fingerprinting can be useful to identify various strains of V. parahaemolyticus in contaminated seafood including bivalve mollusks. This will help to trace the source of contamination by this pathogen. Once the contaminating strain are identified, appropriate precautions can be taken to selectively discard the seafood samples, thus helping the seafood industry from financial losses and help further spreading of the disease. The objectives of the present study were to optimize the AP-PCR approach to generate genomic DNA fingerprints of pathogenic K+ and non-pathogenic K-strains of V. parahaemolyticus and test the applicability of this approach in artificially contaminated oyster tissue homogenates.
Chemical Mixtures: Effects of Chlorpyrifos, Dieldrin,and Methyl Mercury on Hyalella Azteca
Year: Authors: Steevens J.A., Benson W.H.
The overall goal of the presented research is to evaluate the interactions of "real-world" bioaccumulative chemical mixtures having the potential for toxicological effects not predicted from single chemical toxicity experiments. The toxicological effects of the individual model chemicals, dieldrin, chlorpyrifos, and methyl mercury were evaluated using the amphipod, Hyallea azteca. Binary chemical interactions of the model chemicals will be characterized and the mechanism underlying the interactions determined. Additionally, bioconcentration data along with toxicological indices will be used to determine the critical body residue threshold concentrations at which toxicological effects occur. This research directly addresses Mississippi Water Research and South Atlantic-Gulf Region priorities related to water quality, particularly with respect to needs addressing protection of water and sediment from environmental degradation.
Continuous Gaging Methodology for Lock and Dam Installations on the Tombigbee River in Mississippi
Year: Authors: Wallace J.S.
The U. S. Geological Survey, in cooperation with the U. S. Army Corps of Engineers, operates continuous-record gaging stations at two lock and dam sites: Tombigbee River at Aberdeen Lock and Dam at Aberdeen and Tombigbee River at Stennis Lock and Dam near Columbus. Stage, lock, and gate data are monitored at the sites and are transmitted via satellite to the USGS office in PearL The data are processed and uploaded to the Internet at http://srv2dmsjkn.er.usgs.gov, and stage and discharge information is published annually in the series, "Water Resources Data for Mississippi." Information is collected at gages on the headwater, tailwater, each individual gate, and the lock structure. Headwater and tailwater stage gages consist of a float-driven shaft encoder housed in a 4.5 x 4.5 ft. aluminum half-shelter over stilling wells on the lock guidewaIls. Tainter-gate gages consist of shaft encoders (one per gate) chain-driven by the gate mechanism. A lock pressure switch, located in the lock tainter valve recess, registers one count when the lock is emptied. AIl data are collected at a central console located in the lockmaster’s control tower. The console consists of a DCP (Data Collection Platform) with a RS-232 output converter and a GOES (Geostationary Operational Environmental Satellite) transmitter. The DCP monitors all encoders and counts lockages as indicated by the lockage counter. The headwater and tailwater stage gages are interrogated by the DCP at 1 minute intervals, and the gate settings are interrogated every 4 seconds. Once an hour, data are logged into the DCP, and every 4 hours, the GOES transmitter sends 8 hours of data (4 hours current and 4 redundant). Data are also routed via RS-232 to a desktop computer where the lockmaster may view the information graphically. The entire instrumentation package operates on 12 volt DC batteries continuously recharged by 120 volt AC power. Discharge can be computed using a USGS computer software program called DAMFLO as the data are received at the USGS office in Pearl. The program is capable of considering many flow scenarios to determine discharge including flow over weirs, flow through orifices, leakage through gates, flow through turbines, flow over spillways, and flow through other control structures. A combination of state-of-the-art monitoring technology and hydraulic analysis using established hydraulic principles are combined to provide the Mobile District ofthe U. S. Army Corps of Engineers with the most current and reliable information available concerning the two gages.
USGS Realtime Stream-Gaging Network
Year: Authors: Turnipseed D.P.
In 1988. the U. S. Geological Survey (USGS) Mississippi District began implementation of a long-range plan to remotely transmit hydrologic information from a Statewide stream-gaging network using the Geostationary Operational Environmental Satellite (GOES). Currently, the District receives data from more than 100 sites in the network via an uninterrupted downlink system that provides the data within minutes of transmission. Data are processed and input to the USGS data base. The information in the data base is made available in a realtime mode to a publicly accessible Internet location that provides the following information for streamgages in the State:<br> .<br> . .<br> ...<br> Current stage (in feet) and discharge (in cubic feet per second) Realtime discharge (in cubic feet per second) hydrograph and long-term median daily discharge for most sites for the seven most current days Realtime river stage (in feet) for the seven most current days Station description including location. selected. selected basin characteristics, and gage history Flood stage and discharge (National Weather Service forecasted sites) For selected sites tlrroughout the State, the District provides more frequently transmitted river stages during flood events, generally within minutes of the time of the measurement. These data are localed al the following Internel address: hltp://srv2dmsjkn.er.usgs.gav/n-cgi/gen_tbCpg In addition to providing realtime river stages, discharges, flow statistics. and other hydrologic data via the Internet. a wealth of historical daily mean discharge, annual peak stage, and annual discharge data for active and inactive streamgages are also available. These data are localed at the following Internet address: http://h2o.usgs.gov/swr/MS
Contaminants in Fish Tussue in the Lower Mississippi River
Year: Authors: Kleiss B.A., Justus B.G., Folmar H.G.
Contaminants were measured in fish tissue samples from eight sites on the lower Mississippi River and one site on the lower Yazoo River. The samples consisted of composites of eight whole common carp (Carpinus carpio) captured by electroschocking. Duplicate samples were collected at two of the sites for quality assurance, The Mississippi River sites are spaced approximately 15 to 20 river miles apart, from near Mayersville, MS, south to Waterproof, LA, with four of the sites upstream from the confluence of the Yazoo River and four below, Samples were also taken from the Yazoo River, approximately 10 river miles upstream from its confluence with the Mississippi River. Measurable levels of PCBs, toxaphene, dieldrin. DDE, DDD, and chlordane were found. There was no apparent upstream-downstream trend. Values of the DDT degradation products and toxaphene were considerably higher in the samples collected from the Yazoo River than in the Mississippi River samples. However, Mississippi River samples upstream and downstream from the Yazoo River confluence were similar, suggesting that the Yazoo River drainage had no measurable effect on total DDT or toxaphene levels in tissue of Mississippi River fish. Dieldrin and chlordane were found at low levels at 85% of the sample locations and showed no trends. Although found at low levels, PCBs were higher in the Mississippi River samples than in the Yazoo River samples, indicating a source of PCBs outside of the Yazoo River basin.
Hydrology Tools for Wetland Determination
Year: Authors: Rodrigue P.B., Woodward D.E.
This paper describes each of the hydrology tools and gives a brief description of their use. Supporting information is described, including WETS tables that provide long-term weather data reporting stations for most counties across the nation. There can be multiple reporting stations in anyone county. The WETS tables include precipitation normals as well as defining the growing season for the particular location. WETS tables can be downloaded from the Internet. Hard copies of WETS tables are available in Section I, Field Office Technical Guide in NRCS field offices. The hydrology tools have proven successful in a wide variety of landscape settings in different regions of the United States. These tools have also proven effective using different lengths of time of continuous inundation or saturation. Hence, if the laws regarding critical duration of saturation or inundation to produce wetland hydrologic conditions were to change, the hydrology tools would remain valid procedures (Woodward and Warne 1997).
Urea-Independent Acid Tolerance Response (ATR) in Helicobacter Pylori
Year: Authors: Vickery M.C., Southern B.D., Foster J.W., Bej A.K.
Helicobacter pylori is a Gram negative spirillum found in close association with the gastric mucosa and has been identified to play a potential role in causing gastritis and gastrointestinal ulcerative diseases in humans. The primary source of infection by this pathogen in humans has been attributed to contaminated ground water. This organism bas even been detected in deep well water. A number of reports have proposed that adaptation and survival of this pathogen in a gastric acid environment is due to their ability to utilize urea to form ammonia through urease activity, creating a microenvironment of relatively higher pH. The mechanism by which this bacterium can survive the fairly low pH conditions that are often encountered in ground water, which is normally relatively urea-free, has not yet been determined, and this is the subject of this study. It has been reported that adaptation to an acidic pH environment in many of the microbial pathogens such as Salmonella typhimurium, Escherichia cali, and Aeromonas hydrophila requires exposure to relatively mild pH (pH 6.0-4.5) which results in alteration of the cellular protein profile. Some of these proteins have been characterized as "stress" proteins and others as "acid responsive" proteins. Therefore, these microorganisms manifest physiological adaptation (possibly with underlying genetic mechanisms) to acidic pH environment. In addition to these microbial pathogens, naturally occurring microorganisms that colonize in the human gastric environment and are urease positive, such as Lactobacillus, have survival mechanisms that have not been attributed to their ability to catalyze urea to ammonia and CO, to increase the surrounding pH to an alkaline level. H. pylori produces massive quantities of urease at the cell surface and urease activity remains highly active in an acidic pH environment. Whether H. pylori has adapted to the acidic pH environment using underlying physiological and genetic mechanisms like other acidopbilic microorganisms such as Lactobacillus, or has adapted via activity of its urease enzyme alone, is a question that needs to be addressed in order to better understand how this organism is able to survive in the natural environment.
The Effect of Best Management Practices The Effect of Best Management Practices on Fluometuron Sorption
Year: Authors: Shankle M.W., Shaw D.R., Kingery W.L.
Herbicide retention primarily refers to adsorption, which is defined as the accumulation of a pesticide or other organic molecule at either the soil water or the soil-air interface resulting in molecular layers on the surface of soil particles (Koskinen and Harper 1990). Adsorption is an important reversible process that is generally measured by herbicide disappearance from solution. However, it can be extremely difficult to distinguish between true adsorption and general sorptinn. Sorption is a term that generally refers to chemical loss from solution that includes adsorption, absorption, and precipitation (Koskinen and Harper 1990). When a herbicide is absorbed, it can move into the interior matrix of the colloidal fraction (clay minerals and humus) or plant biomass and become tightly bound. If precipitation occurs, the herbicide molecule could form a separate solid phase or covalently bond to the colloidal surface (Harper 1994). The influence of BMPs may change immediate soil rhizosphere constituents, hence a change in the physicochemical dynamics of compound retention, transportation, and transformation. This rhizospheric change of succession may differ among different BMPs. The organic matter content, clay type, and microbial environment may be changed over time due to factors such as sediment and herbicide deposition. Therefore, watershed management that directs runoff water flow through an established filter strip or riparian forest could increase the quality of water in nearby lakes. To ascertain the influence of these BMPs on water quality improvement, an initial investigation was conducted to determine the potential for fluometuron and sediment retention throughout the BMP areas. In order to achieve tltis objective, research was conducted to determine soil properties and fluometuron sorption in soil from an established grass filter strip, riparian forest, and adjacent cropped watershed epipedon at Beasley Lake in Sunflower County, Mississippi.
Implementation of Water Quality Components in the Watershed Modeling System (WMS)
Year: Authors: Deliman P.N., Ruiz C.E.
The Watershed Modeling System is a comprehensive graphical user environment for conducting watershed hydrologic analysis. The model was developed by the Engineering Computer Graphics Laboratory of Brigham Young University in cooperation with the U. S. Army Corps of Engineers Waterways Experiment Station. Features of the WMS include pre- and post-processing support, GIS/CADD links, finite difference/finite element grid generation, 2D data interpolation/visualization, AVI video file anima- tion, use of NEXRAD radar or Battlescale Forecast Models as inputs to 2D spatial models, and the ability to import digital terrain data Models which are currently continued in the WMS include HEC-1, TR-20, and CASC2D. Currently, the models contained in the WMS lack water quality components. This research effort describes the implementation ofwater quality components into the WMS. Plans are underway to incorporate the Hydrologic Simulation Program - Fortran (HSPF) into the WMS as well as add water quality capabilities to CASC2D. HSPF is one of the most widely used lumped parameter water quality models currently used in the country. It is anticipated that the addition of the water quality components into the WMS will increase the utility of this state-of-the-art system. The system will be able to be applied to studies investigations of problems involving watershed water quality and contaminant modeling.
Channel-Bed Degradation and Aggradation on Yalobusha River and Selected Tributaries Upstream of Grenada Lake Near Calhoun City, Mississippi
Year: Authors: Wilson, Jr. K.V.
Channel-bed degradation and channel-bank widening in the upper channel reaches of Yalobusha River and its tributaries have contributed to channel-bed aggradation on the Yalobusha River between State Highway 9 and Grenada Lake. The aggradation has caused channel blockage on the Yalobusha River downstream of State Highway 9 near the mouth of Topashaw Creek near Calhoun City, Mississippi. The U. S. Army Corps of Engineers, Vicksburg District, is considering removing the channel blockage and constructing erosion control features in the upper river basin. The U. S. Geological Survey, in cooperation with the U. S. Army Corps of Engineers, Vicksburg District, has operated streamflow gaging stations since 1948 on the Yalobusha River and Topashaw Creek Canal at State Highway 9 about 0.3 and 2.7 miles south, respectively, of Calhoun City. Because of intermingling flows upstream of the two gages, streamflows at each of the gages are added together and published for the combined drainage area of 305 square miles. These gage data were supplemented with recent channel-stability analyses for the Mississippi Department of Transportation for State Highway 8 bridge replacements of the Yalobusha River tributaries between Calhoun City and Vardaman. These data were used to describe channel-bed degradation processes that have occurred in the upper channel reaches and aggradation processes that have occurred just downstream of the gages. Since the last channelizations were completed on the Yalobusha River and Topashaw Canal by I968 and on the Yalobusha River tributaries by 1970, the Yalobusha River and Topashaw Canal have effectively aggraded about 5 and 4 feet, respectively, just downstream of State Highway 9. The Yalobusha River has degraded about 9 feet at State Highway 341 about 8.7 miles upstream of State Highway 9. Cane Creek, one of the tributaries recently studied along State Highway 8, has also degraded as much as 9 feet.
Fish Utilization of Riparian Habitats Created by Erosion Control Structures
Year: Authors: Smiley, Jr. P.C., Knight S.S., Cooper C.M., Kallies K.W.
Field-scale grade control structures (drop pipes) are utilized to control gully erosion occurring adjacent to incised streams undergoing restoration as part of the Demonstration Erosion Control (DEC) project in the Yazoo River basin. Over 2,000 structures were planned for installation or constructed as part of the DEC project (Shields et al. 1995a). A drop pipe consists of a dam with an "L" shaped metal pipe passing through it (Figure I). Both structural features function in erosion control. The dam causes water to pond, thus reducing the runoff velocity and its sediment transporting capacity. The drain pipe conveys runoff from the field level to the stream level and prevents overbank flow. Additionally, installing this structure results in the replacement of eroding gullies with riparian habitats located at the field level of incised streams (Cooper et al. 1997; Smiley et al. 1997) and small pools located at the outflow of the pipe within the stream channel. Our objectives for this research were to: I) describe fish communities within drop pipe created habitats by examining species composition. species richness, number of captures, and number of fish captured per unit effort (NPUE), and 2) determine the relationship of pool surface area and depth with fish species richness and NPUE within drop pipe created habitats.
Mutagenecity Effect of Surface Water in the Lower Stream of the Mississippi River
Year: Authors: Yang W.H., Yang J.R.
The aquatic systems all around the world have been found to be seriously polluted with toxic organic and inorganic chemicals, and waste products (Callahan et al. 1979; Edward et aI. 1979; Bakre et al.1990; Rehana et al. 1996). Civilian activities along the river contaminate the surface water with huge amount of waste materials and products coming from humans, animals, industrial plants, housing establishments, and factories. Increased usage of fossil fuels in the process of transportation, heating, and power generation resurface the accumulated old pollutants in the fossil fuels. Lately, the chemical industries added a variety of new synthetic compounds, including insecticides to the environment pollution. As the Mississippi River runs through the highly active industrial, agricultural, and populated areas in this country, the constant survey of the toxicity of the surface water of this river appears to be very important for the safety ofpopulation along the river. This study intends to apply the Salmonella bacterial mutagenic test for evaluation of the most basic genotoxic effect of the Mississippi River water in its down stream areas. By application of the estimated correlation coefficient for phase analysis and the statistical mean value for significant analysis in the bacterial mutagenicity assay, this study intends to give a more detailed and accurate assessment of the genotoxicity potential of the Mississippi riverwater from Memphis to Greenville, Vicksburg to St. Francisville, and from Baton Rouge to the Marine Transportation Center.
Genotoxic Effect of Hydroquinone and Elone (Mono-Methyl-Para-Aminophenol Sulfate)
Year: Authors: Yang W.H., Harris J., Jeffries B., Cooper A., Yang J.R.
Since the origin of life, hydroquinone derivatives appear to be a popular group of organic chemical in the metabolic pathway of several aromatic amino acids in the first cell. As anaerobic cells evolved to aerobic or phototrophic cells, various hydroquinone derivatives are found to be very important co-factors for biological functions. Ubiquinone and Plastoquinone (Leonard et al. 1987; Weiss et al. 1987) are important coenzymes for the transport of electrons and protons across the membrane for ATP synthesis in the mitochondria and the chloroplasts. These stable and active chemicals occupy large proportions of the cell components and are expected to contribute to a large proportion of the biological waste material in the environment. In addition, both hydroquinone and its derivative, elone (Mono-methylpara- aminophenol sulfate) are the most commonly used reducing agents in the photographic industries. It is a proposed anticancer drug and an antioxidant (Baehner et al. 1983: Packer et al. 1973: Green et al. 1973). Furthermore, hydroquinone derivatives are prevailing as popular in our living environment, pharmaceutical drug market, and important chemicals in our industries. The genotoxic safety tests of these chemicals have not been further studied. The current study is intended to investigate the toxic effect of hydroquinone and elon by 2 assay methods. The first method is to assay the quantity of DNA strandbreak by monitoring conformational change of SV-40 viral DNA in vitro (Alder et al. 1973). The second method is to assay the number of reverse mutants (revertants) of Salmonella test strains in vivo (Ames et al. 1975). Data obtained by the two assays will be employed for a more rational approach of estimating the effect of hydroquinone and elone to DNA and gene function.
Natural and Anthropogenic Control on the Geochemistry of Northern Gulf of Mexico Estuarine Sediments
Year: Authors: Isphording W.C., Perry H.M., Trigg C.B.
Pritchard (1967) defined an estuary as "a semi-enclosed coastal body of water which has free connection with the open sea and within which seawater is measurably diluted with fresh water from land drainage." Estuaries are transition zones between marine and non-marine depositional systems. Sixteen major estuaries are present in the Gulf of Mexico between the Florida Keys and the Texas-Louisiana border (Figure I). Annually, they receive nearly 50 perrent ofthe total drainage from the continental United States. Each second, approximately one million cubic feet of water enters the Gulf of Mexico through the numerous bays and estuaries that fringe the southern margin of the United States (Wilson and Iseri 1969). The quantity of water entering the Gulf of Mexico, however, is not evenly distributed. The area west of the Mississippi River represents about 20 percent of the Gulf drainage, but because of its drier climate supplies only six percent of the total discharge to the Gulf. The area east of the Mississippi River watershed and extending to the eastern margin of the Apalachicola River basin encompasses seven percent of the total Gulf drainage area, but contributes 18 percent of the total discharge because of its wetter climate. The Mississippi River watershed system receives runoff from nearly 1.2 million square miles and provides over 70 percent of the total discharge from the United States to the Gulf of Mexico. Unlike the Mississippi River which discharges directly into the Gulf of Mexico, most of the remaining rivers discharge into the estuaries and these, in turn, trap significant portions of the transported sediment load (Table 1). The numerous watershed areas emptying into these systems drain regions of marked diversity in bedrock and population; hence natural and anthropogenic contaminants carried by the rivers differ widely (lsphording et al. 1989). Further, because of differences in the flow regimes of the contributing rivers and the physical parameters operating in each basin, each of the bays is characterized by distinct differences in sediment composition and texture. These differences control the quantity and manner by which contaminants that are transported into the bays as natural, municipal, and industrial effluent become incorporated into the sediments (lsphording et aI. 1985, Isphording et aI. 1989).
Assessment of Environmental Estrogens in Wastewater: Potential for Developmental and Reproductive Toxicity in Fish
Year: Authors: Benson W.H., Schlenk D.K., Arcand-Hoy L.D., Nimrod A.C., Tilton F.
The following is a review of the literature that describes the background material which initiated our current research activities sponsored by the Mississippi Water Resources Research Institute. This manuscript describes the basis for the hypothesis that pharmaceutical products are reaching aquatic systems at biologically active concentrations. A brief overview of the current uses of estrogen in the United States is presented. From these data an estimate of the concentration of natural and synthetic estrogens reaching wastewater receiving stations is calculated using an expected introduction concentration. Finally, the biochemical processes that alter these compounds occurring in humans and microbial populations in wastewater treatment plants is also reviewed.
Enhanced Biodegradation of Organic Wood-Preservative Contaminated Wastewater by Commercial Surfactants
Year: Authors: Diehl S.V., Borazjani A.
The broad objective of this study was to evaluate different commercial surfactants for enhancing the biodegradation of wood-preserving process wastewater containing a high concentration of PCP, PAHs and oil and grease. Specific objectives were: (1) screening selected anionic and non-ionic surfactants for interference on PCP and PAHs, analyses by gas chromatography (GC); (2) testing for the toxicity of the surfactant itself to degrading microorganisms; and (3) testing different concentrations of selected surfactants to determine the best concentration for degradation as well as the least inhibition toward microbial growth.
Vascular Plant Species Native to Northern Mississippi for Use in Constructed Wetlands for Wastewater Treatment
Year: Authors: Davis S.A., Holland M.M.
The University of Mississippi (Figure 1) has established The Center for Water and Wetland Resources (CWWR) to be located at The University of Mississippi Field Station (UMFS). Due to the hydrology and geology of the area, traditional wastewater treatment is not feasible to service CWWR As a result, a constructed wetland system has been proposed for the wastewater treatment. The design of the six wetland cells is flexible in that the engineers are challenging researchers to suggest manipulations of the vegetation component. Dr. Bill Wolverton, the engineer designing the system, has traditionally worked on systems along the coast and uses tropical broad-leaf vegetation. When the immediately CWWR plans were first proposed, interest was directed towards trying native vegetation in this system. The use of native species supports the UMFS goal of maintaining biodiversity and the UMFS User Committee’s desire not to encourage introducing exotic species which may become invasive. UMFS is at the headwaters of the Bay Springs Creek which flows into the Little Tallahatchie River. This project does not focus on the design issues of this system, but rather focuses on the vegetation composition. Current research agendas such as SBI (Lubchenco et aI. 1991), FWI (Naiman et aI. 1995), and the agenda set by the Organization of Biological Field Stations (Lohr et.aI. 1995) have set priorities establishing long-term programs for freshwater research relating directly to improving watershed management and human sustainability. With the widespread misuse and alteration of watershed dynamics, watershed data acquisition is essential. This research project is connected to these agendas in that it examines the biodiversity of native vascular plant communities in northern Mississippi and reviews literature on the resilience of individuals to anthropogenic stress within constructed wetlands for wastewater treatment.
Preliminary Analysis of MSEA Lake Water Quality
Year: Authors: Knight S.S., Cooper C.M., Cash B.
The Mississippi Delta MSEA (Management Systems Evaluation Area) is a competitive agricultural systems-based research project designed to address the problems associated with these non-point source pollutants. The Mississippi Delta MSEA is unique among MSEA projects both because ofits location in the Mississippi River alluvial plain and its strong ecological research component. Experimental design ofthe Mississippi Delta MSEA calls for the development of comprehensive land and cultural treatments targeted to reduce sediment and associated pollutants entering watershed oxbow lakes. Major objectives of the MSEA project are: I) to develop and evaluate alternative and innovative farming systems for improved water quality/ecology in the Mississippi Delta; 2) to increase the knowledge to design and evaluate economical environmentally-sound best management practices (BMPs) as components of farming systems; and 3) to increase awareness and adoption by farmers/landowners of alternative farming systems to reduce adverse agricultural impacts on water resources and ecological processes. To evaluate the efficacy of a management strategy such as the one proposed for the Mississippi Delta MSEA Project, a thorough understanding of pre-project conditions and ecological processes is required. This study examines and documents pre-management water quality conditions on three oxbow lakes prior to the implementation of Best Management Practices.
The Hydrovision Graphical User Environment
Year: Authors: Bowie R.M., Khan A.A., Wang S.S.
HydroVision was developed to support computational models of free surface flow with transport phenomena and sedimentation processes. In particular, HydroVision was developed to support the family of models developed at the CCHE based on tbe efficient element method of Wang & Hu (1992). These models all use a structured grid system for the discretization of the study domain. The current version of HydroVision, which is in Beta release, supports the depth integrated unsteady model known as CCHE2D. HydroVision provides graphical support of grid generation, specification of initial and boundary conditions, simulation control/monitoring, and visualization. Each of these will be discussed further in the following sections.
Occurrence of Pesticides in Rain and Air in Urban and Agricultural Areas of Mississippi, April-September, 1995
Year: Authors: Coupe R.H., Manning M.A., Forman W.T., Goolsby D.A., Majewski M.S.
There have been several studies that have examined the movement of pesticides in the atmosphere, and an excellent review of many of the major studies is in Majewski and Capel (1995). In Mississippi, there have been a limited number of studies on the transport of pesticides in the atmosphere. Many of these studies have dealt with the volatilization of pesticides after application (Hollingsworth 1980; Willis et al. 1980; Harper et al. 1983; and Willis et al. 1983). Hollingsworth (1980), examined volatilization of trifluralin after incorporation; the other studies examined toxaphene or DDT or both. Arthur and others (1976) collected weekly air samples and analyzed them for a suite of pesticides, most of which have since been discontinued in the United States. There have been a few national studies that have included agricultural and urban sites in Mississippi, (Tabor 1965; Stanley et al. 1971; and Kutz et al. 1976), but these studies focused on pesticides that were then in use, most of which are no longer used in the United States. There have been no studies on pesticides in the atmosphere in Mississippi in recent years. The purpose of this paper is to present the results of a study of pesticides in rain and air from April 12 to September 19, 1995, collected from an urban and an agricultural setting in Mississippi by the U.S. Geological Survey (USGS).
Water Quality Assessment of Floodwater Retarding Structures
Year: Authors: Cullum R.F., Cooper C.M.
The objective of this paper was to evaluate the effect of floodwater retarding structures and low flow augmentation on water quality. Four gauging sites for stage-discharge relationships and water sampling for sediment and chemical analyses were positioned on undisturbed reaches of the Otoucalofa Creek in close proximity to the NRCS standard earthen design dams. Gauging sites were established three years prior to the 1994 construction of dams to establish background flows and sediment loadings.
Current Woody Vegetative Community Structure and Composition in a Sixteen Kilometer Stretch of the Little Tallahatchie River Influenced by the Sardis
Year: Authors: Pigott K., Holland M.
The responses of ecosystems to perturbation, especially those involving nonlinearities and irreversibilities, have barely been explored (Daily et al. 1996). There is a need to determine the patterns and responses of ecological indicators to stress and to monitor the recovery of damaged ecosystems (Lubchenco et al. 1991). Therefore, we proposed to determine the pattern of vascular plant species structure and composition in a forested wetland. Bottomland hardwood forests are one of the dominant types of riparian ecosystems in the United States, particularly in the Southeast (Mitsch and Gosselink 1993). Riparian vegetation occupies one of the most dynamic areas of the landscape with abundance and composition differing greatly among riparian successional stages. With the high diversity of micro-sites and disturbance regimes, there is a greater diversity in the riparian zone than in up-slope habitats (Gregory et al. 1991). Bottomland hardwood wetlands are very diverse with vegetation adapted to long hydroperiods in low lying areas of the wetland to less flood tolerant species occupying higher areas. In bottomland hardwood wetlands, the physical environment is one of the major determining factors influencing species distribution (Bell 1974; Hodges 1998). Bottomland hardwood wetlands are subjected to flooding periodically throughout the year with soils becoming saturated. Also, the prevalent trees associated with this type of habitat are particularly suited to these inundations during the growing season as well as other times of the year (Teskey et al. 1978; Cowardin et al. 1979; Mitsch and Gosselink 1993; DeShield et al. 1995). Thus, the hydroperiod’s flooding duration, intensity, and tinting are the ultimate factors in determining the structure and function of bottomland hardwood wetlands (Mitsch and Gosselink 1993; Conner 1994).
Comparison of Enzyme-Linked Immunoassay with Gas Chromatography/Mass Spectrometry for Analysis of the Cotton Herbicide Fluometuron
Year: Authors: Bastian K.C., Thurman E.M., Rebich R.A.
Traditional methods of herbicide analyses include high pressure liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS). Both of these methods require sophisticated equipment and are fairly labor intensive, thus raising the cost of analyses. In addition, both methods generally require a fair amount of time and a large volume of sample to physically conduct the analyses. Because about 200 to 300 samples are collected each year for herbicide analyses as part of the MDMSEA project, a method was needed that would provide results that were cost effective, timely, and required a smaller sample volume. One method that has the potential to meet the requirements of the MDMSEA project for herbicide analyses is enzyme-linked immunosorbent assay (ELISA). This procedure, which is based on immunological responses to target analytes, was chosen because of its low cost, quick turnaround times, and small sample-volume requirements. ELISA has been used in similar ways to examine triazine herbicides and metabolites in surface water (Thurman et al. 1990) and rainfall (Pomes et al. 1998), acetanilide herbicides and metabolites in surface water (Aga et aI., 1994), and other herbicides in soil and water (Aga and Thurman 1996). In typical environmental ELISA protocols, the target anaiyte (in this case, fluometuron) and an enzyme conjugate, which mimics the action of the target analyte. compete for binding sites on polyclonal antibodies bound to a well in a microtitre plate or to a magnetic particle (Aga and Thurman 1996). After the analyte(s) and enzyme conjugate have been given time to bind to the antibodies, the remaining solution is washed away and the conjugate is allowed to catalyze a colorimetric reaction, allowing for spectrophotometric quantitation of analyte concentration. As these are competitive assays with color production caused by the enzyme conjugate rather than the presence of the analyte, color intensity varies inversely with analyte concentration.
Aspects of Seasonal Field Flooding: Water Quality and Waterfowl
Year: Authors: Maul J.D., Cooper C.M.
Winter flooding of agricultural land is frequently used as a cost saving measure for farmers and for providing habitat to non-breeding waterfowl. Field-flooding potentially provides simultaneous advantages to landowners and wildlife by: (I) preventing sheet, rill, and gully erosion, (2) decreasing herbicide application costs, (3) improving water quality of runoff, and (4) providing high energy foods and refuge for migrating and over-wintering waterfowl. Furthermore, field flooding is an essential component of national waterfowl management strategies in an effort to provide adequate foraging habitat to meet waterfowl population goals. In this paper, we provided information pertaining to flooded agriculture that will benefit land and wildlife managers alike. Water quality data concerning flooded agriculture give land managers useful information regarding soil retention and drawdown dynamics. Experimental field use data and discussion on waterfowl use of flooded cropland will add to the wildlife information base and contribute to future field management decisions. Our primary objective was to address water quality characteristics and waterfowl responses to seasonal field flooding. Specifically, we examined: (I) waterfowl densities within flooded fields planted with two different crops (soybean and Japanese millet), (2) baseline water quality data from flooded rice fields and moist-soil wetlands, and (3) habitat effects on time-activity budgets of non-breeding waterfowl observed in flooded rice fields and moist-soil wetlands.
The Potential for Cryptosporidium in Mississippi’s Drinking Water
Year: Authors: Sparks J.T., Sherrard J.H.
Cryptosporidium parvum is a one-celled parasite which has been recognized as a human pathogen since 1976. However, only within the last decade has attention been focused on cryptosporidiosis as a potential waterborne disease, when Cryptosporidium was linked to several municipal outbreaks of intestinal illness, including the 1993 incident in Milwaukee in which over 400,000 persons were infected. Cryptosporidiosis is an acute diarrheal illness in humans, against which there is currently no effective medical treatment The parasite is spread by the ingestion of oocysts excreted in the feces of infected individuals or animals and can be transmitted through the ingestion of contaminated food or water. In immunocompetent individuals the symptoms are self-limiting and normally last from 5 to 14 days. For the immunocompromised individuals (including but not limited to the young and elderly, transplant patients, and HIV-infected individuals), the illness can be debilitating and may even be fatal. Surveillance of raw water sources has confirmed that oocysts of Cryplosporidium are ubiquitous in surface waters. The number of oocysts may be considerably larger if the raw water source has been contaminated by raw sewage, treated wastewater, or runoff from livestock or wildlife grazing areas. Contamination of drinking water bas not been limited to facilities obtaining their raw water source from surface water. Several outbreaks of cryptosporidiosis have been contributed to groundwaters in which the well had been contaminated by either raw sewage or agricultural runoff. The protective shell of the oocysts is very resistant to levels of chlorine typically used for disinfection. While the physical removal of Cryplosporidium through the use of filtration bas been effective when rigorously applied, many cities/communities in Mississippi do not use filtration in their water treatment processes. All outbreaks of cryptosporidiosis occurred in which the facilities were meeting all current state and/or federal standards for drinking water quality.
A Monitoring Well Network for the Gulf Coast Miocene Aquifer System
Year: Authors: Everett J.F., Stewart L.
In spite of these findings, many citizens and public officials were still concerned that saltwater intrusion might occur at some time in the future. In response to these concerns, in 1995 OLWR established a monitoring well network along the Mississippi coast to detect any possible changes in chloride concentrations. This network consists of 34 wells, varying in depth from 330 to 2000 feet, in Jackson, Harrison, and Hancock Counties (Figure 3). Eighteen of these wells are located in Jackson County, nine in Harrison County, and seven in Hancock County. A sample is collected and/or the static water level is measured at each of these wells twice a year - - once in summer, when pumpage is heaviest, and once during winter, when pumpage is reduced. Several criteria were used in selecting wells for this network. First, wells of varying depths were needed for each county, with adequate spacing between wells in the same layer. All wells had to be located near the coastline. Accessibility was an important factor. For example, it is difficult or time-consuming to gain entry to some wells. Reliability of the data was another consideration. We had to be certain of the screened interval of the well and relatively sure that the casing was intact. Wells to be sampled had to be in use. Lastly, preference was given to wells for which good historical data was available.
Back to the Future: Another Watershed Management Approach for the Yazoo River Basin?
Year: Authors: Ballweber J.A.
From earliest settlement, land reclamation and flood control efforts were necessary in Mississippi’s Yazoo River Basin. To be effective, these efforts bad to be planned and coordinated on a watershed or river basin scale. In addition, as reflected generally throughout the Lower Mississippi Alluvial Plain, effective water resource development and management efforts must be planned on a watershed or river basin scale. For example, main stem Mississippi River levees were ineffective without complementary tributary flood control efforts. Similarly, agricultural tributary headwater projects and other voluntary conservation programs to control erosion and reduce sedimentation enhance flood control efforts. A wide range of relevant federal and Mississippi State legal authority coalesces in these two broad watershed management themes of flood control and agricultural watershed management and related land treatments programs. In addition, these themes are often implemented through cooperative, federal, state, and local administrative frameworks on a watershed and/or river basin scale. Federal legal authority for flood control and agricultural projects evolved to include natural resource and environmental considerations in project planning and to allow multiple purpose watershed projects. But until the mid-1980s these issues were addressed on a single resource (e.g., threatened or endangered species, wetlands) or media (e.g., water, air) rather than a watershed basis. In the early 199Os, however, they developed into a distinct theme as the Environmental Protection Agency (EPA) and the U.S. Fish and Wildlife Service (FWS) initiated watershed and watershed based ecosystem management approaches to their missions. The question is: how will this new theme be implemented? Will it go "back to the future" to develop a new administrative watershed management framework or be integrated into the Basin’s existing infrastructure?
Ecological Integrity of Wetland Soils: Testing of Soil Organic Matter and Total Organic Carbon as Parameters for Resiliency of Wetland Soils
Year: Authors: Balducci J.A., Holland M.M., Maul R.S.
The purpose of this project is twofold. The first part focuses on determining whether mature forested wetlands within two separate watersheds located in the subtropical ecoregion are, in fact, similar in regard to soil nutrients. Mature wetlands refer to wetlands that have not been timber harvested for an extended period of time. The mature wetlands in the Chowan River watershed have not been cut in over 80 years. The mature wetlands in the YazooTallahatchie River watershed have not been cut in over 60 years. The comparison of the mature wetlands will determine if, in fact, all mature wetlands witltin tltis study are similar. The second focus is to compare biogeochemical differences among wetlands of different successional stages within the Yazoo-Tallahatchie watershed, Mississippi. By determining if timber-harvested wetlands of different successional stage are different from mature wetlands, then some estimate of resiliency can be made. The objectives of this study were to: (1) determine if there are significant differences in soil organic matter (SOM) and total organic carbon (TOC) content between mature wetlands located in the Chowan River watershed Virginia, and mature wetlands of the Yazoo-Tallahatchie River watershed, Mississippi; and (2) determine if there are significant differences in SOM and TOC content among wetlands of different successional stages located in the Yazoo-Tallahatchie watershed.
Photo-Induced Detoxification of 2,4-Dichloroaniline in a Freshwater Environment
Year: Authors: Hwang H.M., McCullum D.C., Slaughter L., Mayers C.L.
Most organic pesticides, with the exception of very persistent compounds, will undergo transformations either chemically or biologically shortly after application. Most toxicity studies, however, do not take into account the complicated interactions between or among a pesticide .compound and its transformation products and the possible transformation of a pesticide compound into intermediate products of equal or greater toxicity than their parent compound. Photochemical and microbial degradation have been recognized as two important removal forces of many organic pesticides in natural surface waters (Hwang et al. 1986). However, microbial activity is also subjected to inhibitory effect due to the toxicity of pesticide pollutants. Any pesticide that inhibits natural microbial consortia will interfere with microbially-mediated biogeochemical cycling of essential elements and toxicants in natural ecosystems and lead to adverse delayed environmental health impacts. The photoinduced toxicity to aquatic organisms at low concentrations have been reported for some organic pesticide and PAHs compounds (Khan et al. 1973; Landrum et al. 1987: McConkey et al. 1997). This may occur via photosensitization reactions (e.g., production of singlet oxygen) (Ankley et al. 1994) and photooxidation of the compounds to more toxic products such as diols and quinones (David and Boule 1993). Because these chemical species are more water soluble than the parent compounds, aquatic organisms may be exposed to higher concentrations of photoproducts than the parent compounds. Therefore, this presents a greater toxic risk to aquatic organisms and ultimately humans because of direct exposure and/or bioaccumulation through food chains. The extent of this problem suggests organic contaminants and their photoproducts may be degrading aquatic ecosystems and jeopardizing environmental health. Therefore, it is of dire importance to determine the effects of pesticide transformation products on microbial biota while conducting an ecotoxicology study.
Determination of Distinct Hydrogeologic Units within the Mississippi River Alluvial Aquifer Based on Ground-Water
Year: Authors: Gonthier G.J.
The alluvial aquifer is actually an accumulation of many different units that have been deposited in diffferent environments throughout the Pleistocene and Holocene. Three main groups of units include the Pleistocene complexes, the more recent Pleistocene valley trains, and the Holocene alluvium formed from major rivers in the alluvial plain (Figure 1). This report focuses on the hydrogeologic difference between the Pleistocene valley trains and the Holocene alluvium based on previous investigations, drillers’ logs, and historical nitrate and iron ground-water data.
A Comparison of Seasonal Flood Frequency for Annual-Peak and Partial-Duration Flood Series in Mississippi
Year: Authors: Gamble D.W.
The calculation of flood seasonality is rather simple and straight forward. A proportion or percent of the total flood population occurring in one season will suffice. However, two types of flood data can be used to calculate flood seasonality, annual peak flood series (APS), and partial duration flood series (PDS). The APS represents a series of the highest instantaneous peak flow discharge for each year at a given stream gauge station. The PDS represents all instantaneous peak discharges greater than a given ’base flow’ at a given stream gauge station (Dunne and Leopold 1978). Much research has been completed which compares APS to PDS, but this work pertains almost exclusively to a comparison of magnitude (Langbein 1949, 1960). In fact, conversion factors are given in order to substitute PDS for APS or vice versa (Dunne and Leopold 1978). Despite this work, one fundamental questions still remains: can it be assumed flood seasonality is the same for APS and PDS? The purpose of this study is to compare flood seasonality of APS and PDS for the state of Mississippi, determining the spatial patterns in differences and similarities.
Use of Acoustic Velocity Methods and Remote Sensing Techniques to Measure Unsteady Flow on the Lower Yazoo River in Mississippi
Year: Authors: Turnipseed D.P., Cooper L.M., Davis A.A.
This report describes acoustic-signal methodology and remote sensing techniques used to compute discharge during periods of varied, non-uniform flow caused by backwater from the Mississippi River and presents streamflow data collected by the USGS in 1996-97 for the lower Yazoo River. These data were computed with data collected by using conventional streamgaging methods, an ADCP to measure three-dimensional velocity profiles, and a continuous-recording acoustic velocity meter (AVM). Examples of continuous stage, velocity, and discharge computed with data obtained from the Yazoo River gage are presented for low and medium flows. A separate computation method was developed and is presented for locating discharge at the site during high-flow conditions by using a combination of acoustic sensing instruments, global positioning system (GPS) equipment, and remote sensing technology.
Mississippi River/Alluvial Aquifer Interaction at Specific Sites in Northwestern Mississippi
Year: Authors: Bryant C., Dowty S.
In the fall of 1992, staff of the Office of Land and Water Resources began an investigation to determine the hydraulic connection or interaction between the Mississippi River and tbe Mississippi River Valley alluvial aquifer (MRVA) in the Yazoo Basin of northwestern Mississippi (the Delta). This can best be studied on a site-specific basis. Results of the study at six ofthese sites that were selected are presented in this paper. Several questions regarding each site were asked. The first dealt with how far out into the Delta (away from the river) could the influence of the river be observed. The second question centered on the "ground-water divide" at each site. How far from the river is it located and how does it vary or migrate throughout each year? The next question was what determined the distance over which recharge from the Mississippi River extended? The obvious answer to this question lies in trying to understand the geology at each site.
Incorporating Natural Climate Patterns into Management Plans for Swine Wastewater Lagoons
Year: Authors: Wax C.L., Pote J.W.
In a land application system, the level in the lagoon rises during periods of precipitation, while the soil becomes wet and the net water reqnirement of plants decreases, precluding irrigation. Therefore, at the moment of greatest need, this type of disposal system is not operational. Conversely, during periods of clear weather, the level in the lagoon may drop from evaporation, the soil will become dry, and the water requirements of plants are immediate, allowing proper disposal of the wastewater. As a result, the climate may establish a panern in which the supply of water to be disposed of and the water requirement of plants and soil are out of phase. Therefore, a climatological analysis can provide management considerations regarding the capability of this disposal method. The objectives of this research were to: 1) develop analyses that account for climatological effects on design and performance of land application of swine lagoon effluent; 2) derive management strategies based on these climatological effects and demonstrate the impact of these strategies by computer simulation; and 3) define the optimum management strategies and probabilities of failures while employing these strategies in waste disposal.
Integrated Data Resources for Source-Water Protection
Year: Authors: O'Hara C.G.
The U. S. Geological Survey (USGS), Water Resources Division (WRD), Mississippi District, has developed several geographic information system (GIS) projects relating to source-water protection that require the continuous, uninterrupted availability of hydrologic and spatial data. In conducting these projects, District personnel and cooperators outside the District need to access these data and software applications in a reliable manner. To provide this capability, the District has investigated "server-clustering" technology specifically in the areas of failover of "mission-critical" data, applications, and web services. The Mississippi District’s approach to the problem of potential failure of mission-critical computer functions is to develop a Microsoft New Technology (NT) "availability" Cluster Server (MSCS). Also, a significant component of the GIS data that will be needed by these projects are image files such as the new USGS Digital Raster Graphic (DRG) file (image versions of USGS topographic maps). To provide an on-line method for accessing all the DRG files for all quadrangles in Mississippi, the Mississippi District is using a magneto-optical jukebox server that works with the cluster server in providing access to large-format image data.
Preliminary of Fish Tissue Analysis in the Mississippi Embayment NAWQA Program
Year: Authors: Kleiss B.A., Justus B.G.
As a standard part of the U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Program, biological tissues are collected from sites within each project area to determine the occurrence and distribution of trace elements and organocWorine compounds (Crawford and Luoma 1992). Tissue analysis is widely used to detennine the occurrence of contaminants in the aquatic environment because the contaminants are often present in higher concentrations in the tissues than in the water due to bioaccumulation, tissue data provide a time-averaged assessment of the contaminants, and tissue data provide a direct assessment of bioavailability. The Mississippi Embayment (MISE) NAWQA project area generally includes the Mississippi River alluvial floodplain between the confluence of the Mississippi and Ohio Rivers south to approximately Natchez, Mississippi, and includes the Mississippi Valley loess hills on the eastern border (Figure I). The landuse of the floodplain is dominated by agriculture; cotton, soybeans and rice are the principal crops. The loess hills are about half agricultural land and half pine forest. The Mississippi Embayment project is one of more than 50 projects that are located throughout the United States. These projects will be undertaken sequentially; that is, 20 projects began in 1991 and have now been completed, 15 projects began in 1994 and are about midway through the field sampling phase; and 15 projects will begin in 1997. This paper presents the preliminary fish tissue data collected as part of the Mississippi Embayment NAWQA project. Additional sites will be sampled during the remaining 2 years of the Mississippi Embayment project in to provide a more complete geographic coverage of the project area.
Processes and Linkages in Southeastern U.S. Streams
Year: Authors: Jackson D.C.
Living with a stream is enhanced by understanding some basic processes of these systems. Fundamentally, it is important to recognize that a stream does not exist in isolation from its surrounding watershed. The stream is not just water in a channel. It is, rather, an integrated system, incorporating terrestrial as well as aquatic dimensions. A continuum of processes along the stream’s course, upstream to downstream, and laterally away from the channel, dictate conditions, events and life forms at a given location in the stream. Internally within the channel, scour, fill, erosive processes, temperature, depth, current velocity, and substrate type (both physically and chemically) operate in concert to set the stage for biological events.
Use of Rainwater for Water Conservation in Mississippi Catfish Ponds
Year: Authors: Cathcart T.P., Pote J.W., Wax C.L.
Water conservation in pond aquaculture has been a significant issue in the Mississippi Delta for some time due to lowering of water table levels. It is possible that, at some time in the future, producer access to groundwater may be limited or become significantly more expensive. It would be useful to have strategies available to decrease dependence upon groundwater should the above scenario occur. Previous modeling work using historical rain data has suggested that ponds could be managed to use rainwater to reduce dependence upon groundwater (Wax and Pote 1990). Recent work along these lines appears to demonstrate that relatively minor modifications to existing ponds and pond management strategies may reduce ground water use even further. A corollary advantage to this approach is a potentially large decrease in the amount of water released to the environment from catfish ponds. Typical catfish production ponds on the Mississippi Delta are levee-type, having surface areas of 5 to 7 ha and maximum depths of 1 to 1.1 m. The most significant determinant of maximum depth has been operator safety during harvesting: when depths much greater than 1.1 m occur, water may fill the wading boots worn by workers and pull them under. The importance of operator safety on the farm has heretofore prevented serious consideration of increasing pond depths. As will be shown below, the elimination of this option may have been premature.
Streamflow and Water-Quality Sampling Network for the Mississippi Delta Management Systems Evaluation Areas (MSEA) Project
Year: Authors: Rebich R.A.
Agricultural activities are a major source of nonpoint source pollution in the Nation. Surface and subsurface waters draining agricultural fields transport nutrients, pesticides, and suspended sediments to streams, thereby contaminating them and sometimes making them unsuitable for designated uses. One of the most intensively farmed areas of the United States is the Mississippi River Alluvial Plain in northwestern Mississippi, a 7,000-square-mile area locally referred to as the "Delta." Agricultural activities in the Delta differ significantly from those in other regions such as the Midwestern United States. The humid sub-tropical climate in the Delta increases dependence of farmers on pesticides, and the crops and cultural practices dictate a different array of pesticides be used than those used in other areas of the Nation. For example, one of the primary crops produced in the Mississippi Delta is cotton. Little ground cover remains after cotton is harvested in the late fall leaving the soil unprotected during the winter rainy season, thus increasing runoff and erosion potential. These factors, in combination with high regional rainfall, increase the chances for chemical movement within soils and water in this area. A research and demonstration project, entitled the Mississippi Delta Management Systems Evaluation Areas (MDMSEA) project, was begun in 1994 with the purpose of assessing the effects of agricultural activities on water quality in the Mississippi Delta and evaluating Best Management Practices (EMPs) as components to Delta farming systems (Rebich et aI., 1995). The U.S. Geological Survey (USGS) began operating a streamflow and waterquality sampling network in the fall of 1995 as part of the MDMSEA project. The USGS part of the MDMSEA project is funded cooperatively With the Mississippi Depattment of Environmental Quality, Office of Pollution Control. The primary objective of the network is to sample and measure storm runoff from agricultural fields that contain BMPs and from fields that do not contain BMPs. Data from the various sites will be analyzed to assess how agricultural practices affect water quality and to evaluate the effectiveness of the BMPs. The purpose of this paper is to describe the streamflow and water-quality sampling network operated by the USGS for the MDMSEA project and to present selected preliminary nitrogen data, March through December 1996.
Data-Collection Methods Used in the Demonstration Erosion Control Project in the Yazoo River Basin, North-Central Mississippi, July 1985 - December 19
Year: Authors: Runner M.S., Burks K.E., Roberts B.A.
In 1984 Congress directed the U.S. Army Corps of Engineers (COE) and the Soil Conservation Service, now the Natural Resource Conservation Service (NRCS), to establish demonstration watersheds for the purpose of studying erosion and sedimentation in agricultural watersheds. One of the selected studies, the Demonstration Erosion Control (DEC) project, is located in the upper Yazoo River Basin in north-central Mississippi. The project is an ongoing, multi-agency effort for the planning, construction, and evaluation of projects to alleviate erosion, sedimentation, and flooding problems in the Bluff Hills that border the Mississippi River alluvial plain. In 1985 the U. S. Geological Survey (USGS) started collecting sediment and water-quality data for the Yazoo River Basin DEC project at the request of the Interagency Task Force on the Yazoo Basin Foothills Erosion and Flood Control. These data are collected to monitor the effects of remediation and stabilization projects in the upper Yazoo River Basin and have been published annually since 1989 by the USGS in the report, "Water Resources Data for Mississippi." The data are also available in the USGS Water Data Storage and Retrieval System (WATSTORE), The purpose of this report is to give an overview of the data collection methods of the USGS for the DEC project during the period July 1985 through December 1996.
Measurements of Tidal Effects on Stage and Discharge on the Jourdan and Pascagoula Rivers Near the Mississippi Gulf Coast
Year: Authors: Floyd P.C.
During September 19-22,1996, the U. S. Geological Survey (USGS) measured stages and discharges on the Jourdan and Pascagoula Rivers near U. S. Interstate Highway 10 (I-10) near the Mississippi Gulf Coast (Figures 1, 2). These measurements were made in cooperation with the Mississippi Department of Transportation and are being used to better understand how tides affect river flows and bridge hydraulics in the gulf coast region. Discharge measurements were made continuously at both sites during low-flow conditions throughout a complete tidal cycle when river stages and discharges were controlled primarily by the tides. Temporary staff gages were installed at each site and datums were established. River stages were determined from the staff gage readings during each measurement. The data collected during these two studies are summarized in this report.
Continuous Flow Measurement for Evaluating the Performance of Constructed Wetlands
Year: Authors: Sculthorpe E.S., Cathcart T.P., Burcham T.N.
There has been a great deal of interest in evaluating the use of constructed wetlands to improve wastewater quality and reduce wastewater quantity, minimizing the land required for disposal. Many studies have shown the effectiveness of free water surface constructed wetlands for removing nutrients such as nitrogen and phosphorous from wastewater (Richardson and Davis 1987; Gersberg 1983; Tanner et al. 1995; van Oostrom 1995; Cronk and Mitsch 1994; Gearheart et al. 1989; Cronk and Shirmohammadi 1994). The goal for constructed wetland treatment of animal wastewater is mass reduction of contaminants, reducing the amount of land area required for the application of contaminants to the land treatment site (Hunt et al. 1995). If a constructed wetland could be shown to reliably reduce nutrient mass, it could improve existing treatment systems. The object of the project reported here was to develop and evaluate an inexpensive continuous flow measurement system used to monitor effluent flow from a free water surface constructed wetland. The impetus for the work was the belief that accurate computation of effluent mass transport (nutrient or water) required, at the leas~ continuous measurement of effluent water flow. Use of timed "grab" samples has been a common method to acquire -42- flow rate data at the time of sampling. Estimates of total flow of water between sampling periods has typically been based on the assumption that mean flow rate during that period is approximately the mean of the 2 timed measurements that bracket it. Total flow is then computed as the product of the mean rate multiplied by the time interval between measurements. As will be seen below, the mean of 2 grab samples is not always a good indicator of mean flow rate between sampling dates.
Two-Dimensional Water Quality Modeling of Walter F. George Reservoir for a Comprehensive Study Introduction
Year: Authors: Tillman D.H.
Future water uses and operations of water resources projects within the Apalachicola-Chattahoochee-Flint and Alabama-Coosa- Tallapoosa River basins (ACF/ACT may have an impact on water quality. Changes, especially in operation procedures in the system, have caused concern for future water quality conditions affecting allowable waste loads, thus impacting future development. A system-wide water quality model (HEC-5Q) was used to address these concerns. However, this model is limited for detailed examination of reservoir water quality. HEC-5Q uses a one-dimensional (lD), longitudinal, and vertical spatial discretization for the river reaches and reservoirs, respectively, which is satisfactory for temperature, but can miss important processes affecting other water quality variables, especially nutrients, algae, and dissolved oxygen (DO) in reservoirs which exhibit strong longitudinal water quality gradients. Since three of the participating states have expressed concerns about several reservoirs within the system, it was decided to model these reservoirs using CE-QUAL-W2 for a more realistic and accurate analysis by including more spatial dimensionality. The three reservoirs were Weiss and Neely Henry, located on the Coosa River, and Walter F. George (WFG) located on the lower Chattahoochee River. This paper will only present the thermal calibration/ verification and scenario results for temperature at WFG. The objective of this study is to provide calibrated and verified 2D water quality models for Weiss, Neely Henry, and Walter F. George capable of predicting future water quality conditions resulting from potential changes in upstream water allocations, upstream waste loads, and/or reservoir operations.
Developing Management Orientations for Largemouth Bass in Bluff Lake, Mississippi, with Historically Variable Data
Year: Authors: Cloutman D.G., Bray G.S., Driscoll M.T., Hockman B., Mareska J.F., Jackson D.C.
Recreational fishing is an important use of Bluff Lake at the Noxubee National Wildlife Refuge in Mississippi. Fishing has been open to the public from March through October each year since 1984. Jennings (1985) reported that proportional stock density (PSD) of largemouth bass (Micropterus salmoides) decreased approximately four-fold during the first six months of fishing in Bluff Lake, indicating possible over-exploitation and need for management of the fishery. In addition to the seasonal restriction, a 356-mm minimum size limit was imposed in 1990 and remains in place. Fisheries management can be as much art as science. Fisheries managers often have to make decisions based on piecemeal data and observations rather than thoroughly planned and statistically designed studies. This paper provides a case history showing how pieces of information such as catch per unit of effort (CPUE), relative condition (Kn; Swingle and Shell 1971), age and growth, creel surveys, and temporal trends in length frequency distributions and PSD (Anderson 1976; 1978) of largemouth bass can be combined to produce management evaluations and recommendations.
Investigatin of the Infiltration Rates of Loessal Soils in Northwest Mississippi
Year: Authors: Rohs T.S., Aughenaugh N.B.
The percolation rate of fluids into soils is a phenomenon important to many disciplines such as agriculture, geohydrology, environmental engineering, etc. Percolation rates relate how much of a fluid enters the subsurface timewise and how rapidly it propagates vertically and laterally. Loess and loessal soils are the primary surface deposits in western Mississippi on the bluffs and uplands adjacent to the Mississippi River floodplain. As a result of the recent economic growth in the northwestern counties of Mississippi, the presence of the loessal soils poses a threat for groundwater pollution due to surface contaminants (i.e. spills, pesticides, etc.) percolating relatively rapidly into and through these porous soils. The majority of Mississippi residences receive their potable water from groundwater that may flow at some depth below loess soils. This investigation evaluated the infiltration rate of loess and loessal soils and assessed the testing methods that are commonly used in the evaluation of infiltration rates.
Modeling the Effect of Sediment Oxygen Uptake on Water Quality in a Eutrophic Oxbow Lake
Year: Authors: Hargreaves J.A., Steeby J.A.
Eagle Lake is a shallow, eutrophic oxbow lake located north of Vicksburg, Mississippi, and nearly adjacent to the Mississippi River. The lake is isolated from periodic inundation by the Mississippi River by a system of water control structures and earthen levees. Water level within the lake can be manipulated during most of the year and is usually drawn down during the winter to expose the shallow lake margins normally supporting luxuriant macrophytic plant growth to the effects of desiccation and cold. Concern has grown in recent years over a perceived decline in the fishery, particularly for centrarchid fishes, in the lake and studies are underway to evaluate possible causal mechanisms. One plausible mechanism responsible for the decline of the fishery may be related to the increased frequency of acute massive mortalities of fish and possible reduced fish recruitment associated with dissolved oxygen depletions. The relative importance of various sinks for oxygen in shallow aquatic systems implicates the potentially important role of the sediment to overall oxygen consumption. The purpose of this study was to evaluate the contribution of sediment respiration to oxygen consumption in Eagle Lake in an effort to evaluate options for reducing the frequency of fish mortalities associated with dissolved oxygen depletions and improving water quality to support a centrarchid fishery.
Changes in the Oxygen Status of a Newly Impounded Reservoir
Year: Authors: Myers J., Kennedy R.H.
Completion of Richard B. Russell Dam in 1983 inundated approximately 10,520 hectares of the Savannah River flood plain to form Richard B. Russell Lake. While a large portion of the flooded basin was clear-cut, nearly 3,640 hectares of forested land were inundated (Shain 1987). Submerged leaf litter and "green" vegetation (standing or freshly-cut woody and vegetative material) were estimated to be 5.0 x 106 kg and 5.6 x 108 kg fresh weight, respectively (Shain 1987). James (1987) determined that leaf litter characteristic of the basin (oak, beech, hickory, and pine) decayed quickly when experimentally incubated in the lake, especially at shallow depths, and predicted high rates of oxygen depletion. High rates of oxygen consumption, as well as nutrient releases were also reported by Gunnison et aI. (1984) using laboratory microcosms containing local soil and litter samples. Because of the large amount of material inundated and the potential adverse impacts on dissolved oxygen concentrations, an oxygen injection (diffuser) system was designed and installed. The two-staged system consisted of a continuously-operated injection system located 1.6 km upstream from the dam and a pulse injection system located immediately upstream from the power-house section of the dam (Kennedy et al. 1995). The latter system was designed to provide supplemental additions of oxygen to insure that tailwater dissolved oxygen concentrations during hydropower operation meet or exceed 6 mg/l, a negotiated target concentration for protection of downstream fish habitat. Although variable in duration of operation (generally, May or June through October or November) and rate of injection (maximum ca. 85-120 tons/day) the system has been operated routinely during summer stratification since 1985. Here we report changes in the oxygen status of Richard B. Russell Lake during the first thirteen years of impoundment relative to reservoir aging and changes in hydrology and reservoir operation. We also evaluate the paradigm of lacustrine development of reservoirs proposed by Baranov (1961).
Integrated Management of Water and Agrochemicals in Agricultural Crop Production Systems
Year: Authors: Fouss J.L., Willis G.H., Southwick L.M.
The primary purposes of water table control are to minimize the time of excess or deficit soil-water conditions in the root-zone and to maximize the utilization of natural rainfall, thus minimizing the amount of subirrigation water required from external sources. Water table management technology has also begun to be used to improve water quality. Controlled-drainage practices have been developed in the Atlantic Coastal Plains region (Gilliam et aI. 1985; Deal et al. 1986) for reducing nitrogen and phosphorus levels in surface/subsurface effluent from agricultural lands. Successful water table control on a large field scale has been reported by Fouss et al. (1989, 1992), for an alluvial soil in the lower Mississippi Valley, when subsurface conduits were used for the dual purpose of controlled drainage and subirrigation. Water table management has a high potential for achieving maximum crop production. water use efficiency, and improved water quality if properly controlled to compensate for changes in weather conditions. Determining when changes are needed in controlled-drainage and subirrigation to optimally manage the water table depth is a major problem for farmers, especially in coastal areas with fine textured soils. In the lower Mississippi Valley, frequent rainfall events can cause large variations in water table depth because of the small, 3 to 8%, drainable soil porosity. Rainfall probability information included in daily and 7-day forecasts issued by the U.S. National Weather Service can be useful to aid the farmer in making management decisions in anticipation of predicted weather changes (Fouss and Willis 1994). This paper presents field test results and performance evaluations for various methods of water table control during the 1996 growing season in an alluvial soil (Commerce silt loam) of the lower Mississippi River Valley.
Influence of Water Table Management on Runoff Losses of Soil-Applied Pesticides
Year: Authors: Southwick L.M., Willis G.H., Fouss J.L., Rogers J.S., Carter C.E.
Subsurface drains not only make possible land preparation sooner in the spring, but also reduce the amount of surface runoff and sediment losses after rainfall. This aspect of subsurface drains therefore leads to reduced levels of agricultural chemical loss in runoff (Skaggs et al. 1994; Bengtson et al. 1995). By rerouting drainage outflow into surface water through the drains, leaching into groundwater can also be reduced. There is evidence that, in some cases, most of the reduction in pesticide runoff losses provided by subsurface drains becomes residual in the soil profile and, therefore, subject to microbial degradation processes, rather than passing into the drains to be discharged into the receiving surface waterway. In earlier work with atrazine and metolachlor, subsurface drains reduced runoff losses, but less than 10% of this reduction was detected in the drain outflow (Southwick et al. 1990a, 1990b). Management of water table depths with subsurface drains may improve the utility of these drains for decreasing the amounts of agrichemicals lost from alluvial soils by way of surface runoff and leaching (Willis et al. 1991; Thomas et al. 1992; Skaggs et al. 1994). For example, if rain appeared imminent soon after pesticide or fertilizer application to the soil surface, the water table depth could be lowered to enhance infiltration and increase within-soil storage capacity, thereby decreasing runoff loss. Alternatively, if the pesticide and/or fertilizer were already incorporated into the soil surface, the water table could be maintained at some elevation above a subsurface drain line to retard agrichemical leaching below the root zone and thereby retain longer the chemical in the biologically active zone for utilization or degradation. The utility of water table management practices for reducing losses of nitrate nitrogen from agricultural fields has been shown in a few studies, but reports of the effect of such systems on pesticide losses seem not to have been published (Thomas et al. 1992; Skaggs et al. 1994) This paper presents results from the 1995 season of a study on the effect of conventional subsurface drainage and of controlled water table on runoff losses of soil-applied pesticides from Mississippi River alluvial soil in southern Louisiana.
CE-QUAL-ICM Three Dimensional Surface Water Quality Model
Year: Authors: Bunch B.W.
In addition to the natural loadings, aquatic systems often are receptors of municipal and industrial wastewater discharges along with polluted rainfall runoff. These loadings can tax the assimilative capability of the system and result in a degradation of water quality which, in tum, can affect living resources such as fish, aquatic invertebrates, filter-feeders, and sub-aquatic vegetation. The degree to which degradation occurs or is due to pollution typically is not easy to determine without conducting a comprehensive study on the physical, biological, and chemical processes at work in the system. The Environmental Laboratory (EL) of the U.S. Anny Waterways Experiment Station has developed a tool for use in answering these and other questions dealing with surface water quality. CE-QUAL-ICM (ICM) is a multi-dimensional surface water quality model developed for the study of eutrophication and anoxia in Chesapeake Bay (Cerco and Cole 1994). Chesapeake Bay water quality has been degraded by municipal and industrial wastewater discharges along with agricultural and other non-point source (NPS) discharges occurring in its watershed. These discharges were blamed for seasonal anoxic conditions in the bottom of the mainstem of the bay, algae blooms, increased levels of nutrients, and a decrease in living resources. Because of the scope of the water quality problem and the number of state and local governments involved, the U.S. Anny Corps of Engineers was selected to perform a water quality modeling study. In this study, ICM was calibrated for a three year period using an extensive data base of water quality observations. Once the model was calibrated, numerous scenarios were performed in which the long term effects of different wasteload reduction plans were determined. Based upon these results, federal and state governmental bodies and regulatory agencies are determining what remediation steps to undertake.
The Potenmtial of Vegetative Filter Strips at Varying Widths on the Reduction of Herbicides in Surface Runoff Water
Year: Authors: Tingle C.H., Shaw D.R., Boyette M.
Vegetative filter strips reduce sediment and other suspended solids, nitrogen and phosphorus, and colliform organisms (Dilaha et al. 1989; Young et al. 1980). Vegetative filter strips 4.6 and 9.1 m wide with shallow uniform flow removed an average of 84 and 74% of incoming suspended solids, 79 and 61% of incoming phosphorus, and 73 and 54% of incoming nitrogen (Dilaha et al. 1989). Stiff grass hedges of Miscanthus sinesis Anderss. reduced soil loss from conventionally-tilled cotton as much as 50% (McGregor and Dabney 1993). Vegetative filter strips reduce pollution from feedlot runoff (Young et al. 1980). These strips, which were comprised of orchardgrass (Dactvlis flomerata L.) and a mixture of sorghum (Sorghum vulgare L.) and sudangrass (Sorghum sudanense L.), reduced off-site movement of runoff and total solids 67 and 79%, respectively. Tall fescue strips 0.5 and 1 m wide reduced herbicide loss at least 48% from conventionally tilled cotton (Gossypium hirsutum L.) (Murphy 1996). Tall fescue filter strips 2 m wide can effectively reduce herbicide concentrations and total losses in soybean planted with conventional tillage or no-till. Metribuzin and metolachlor concentrations were reduced as much as 50% when a vegetative filter strip was used in a tilled monocrop soybean production system (Webster and Shaw 1996). While these data show that vegetative filter strips may effectively reduce herbicide concentrations and sediment, the next reasonable question that arises is the applicable filter strip width to maximize reductions in sediment and contaminants while reducing the amount of land taken out of production by these filter strips. Other researchers have recognized the deficiency of information currently available pertaining to filter strips and their impact on agricultural production systems (Aull 1980). The objective of this research was to evaluate varying tall fescue filter strip widths and their effects on metolachlor and metribuzin loss in surface runoff from conventionally-tilled soybean.
Occurrence of Selected Cotton and Rice Herbicides and Their Metabolites in Streams and Oxbow Lakes of Western Mississippi, Northeastern Louisiana, and
Year: Authors: Joseph R.L., Coupe R.H., Zimmerman L.
The Mississippi Alluvial Plain (commonly referred to as the Delta) is an area of intensive agriculture of mostly soybean, cotton, and rice production. The Delta is a sparsely populated area with a few scattered population centers. The study area is located in the alluvial plain of the Mississippi River. The topography is characterized by relatively flat, poorly drained land with slopes of 0.3 to 0.9 feet per mile. The climate is subtropical with long hot summers and short moderate winters. The average annual temperature at Greenville, Mississippi, near the center of the study area, is 18 C. Average monhly temperatures range from 8 C in January to 33 C in July. Average annual precipitation in Greenville is 51 inches, with the heaviest rainfall occurring from December to April. Minimal rainfall occurs in September and October; however, heavy rainfall producing locally intense runoff can occur at any time of the year. The slow moving streams in the Delta contain silt bottoms and receive large amounts of sediment and other agricultural constituents. Consequently, many streams have relatively high turbidity, elevated nutrient concentrations, and periodically high concentrations of toxic substances (Mississippi Department of Environmental Quality 1992). This paper focuses on the seasonal occurrence, and the relation of use to occurrence, of eight selected herbicides and two herbicide metabolites in surface water.
Construction of Benzene-Catabolizing Bacilli by Transformation and Gene-Fusion with Plasmids
Year: Authors: Yang W.H., Yang J.R.
Aerobic degradation of aromatic hydrocarbons by bacteria was first demonstrated in the early 1900s. Thereafter, various strains of bacteria and fungi capable for degradation of aromatic hydrocarbons were isolated (Gibson et al. 1984). Nevertheless, bacteria capable for degradation of long aliphatic hydrocarbons such as petroleum oil were discovered only recently. A marine bacteria, Acinetobacter calcoaceticus RAG-1, was identified as an oil-degradation microorganism in earlier studies (Reisfeld et al. 1972; Rosenberg et al. 1979 a, b; Shabtai et al. 1985), and actively applied for bioremediation of the beaches in Alaska after the 1989 Exxon Valdez oil spill. Several other naturally occurring bacteria of the genus Pseudomonas which utilize oil as their carbon energy source (Harvey et al. 1990), were also discovered. In the previous studies (Yang et al. 1996a, b) we indicated that it was able to convert the bacilli into gasoline-catabolizing bacilli by plasmid-mediated transformation and gene-fusion with plasmid pTV1Ts. Further study indicated that following such treatment, the bacilli obtained their capability to catabolizing benzene as the only carbon source in the basic medium. It was also possible to enhance the benzene-catabolizing capability of those pTV1Ts-fused bacilli by retransformation and refusion with the additional new plasmid, pLTV1 which contain large portion of similar DNA molecules with pTV1Ts.
Main and Interactive Effects in a Wetland Mesocosm Experiment: Algal Community Responses to Agrichemical Runoff
Year: Authors: Brooks B.W., Chambers J.A., Libman B.S., Threlkeld S.T.
The negative impacts of agrichemical pesticides on various components of aquatic communities have received increased attention in recent years. The potential for interactive effects between multiple agrichemicals is always present, but investigations of multiple agrichemical effects are limited (Parott and Sprague 1993; Sexton et al. 1996). The toxic effects of the suite of agrichemicals in watershed runoff samples will invariably differ from laboratory studies which focus on the independent effects of the chemicals. The need for an experiment to quantify the effects of a mixture of pesticides on multiple endpoints at different trophic levels of wetland ecosystems gave impetus for our present study.
Remediation of Mutagenicity Effect of Herbicides: Atrazine, Chlorpyrifos, Monosodium Methane Arsonate, and Methyl Mercury in Artificial Wetlands
Year: Authors: Yang W.H., Yang J.R., Overstreet K.
Atrazine (ATR) (2-Chloro-4-ethylamino-6-isopropylaminos- triazine) was the first herbicide synthesized for control of weed in agriculture fields since 1959. About 6 years later, chlorpyrifos (CPF) (O.O-Dimethyl-O-[3.5.6-trichloro-2pyridyl] phosphothioate) was introduced into the market to substitute for the more toxic insecticide, DDT [(trichloro-bis (p-chlorophenyl)ethane]. More selective contact grassweed herbicide, monosodium methane arsonate, (MA), was also produced thereafter. The popular use of ATR and MA with DDT or CPF to have combined effects of herbicide and insecticide became a routine practice for increase of agricultural production. However, the massive use of agrichemicals worried many investigators into the possible environmental disaster. It was estimated in 1982 that 95% of all the corn growing region in Iowa was treated with nearly 52 million pounds of herbicide, and 52% of the region was treated with nearly 7.9 million pounds of insecticide (Kelly 1986). It is with great concern that these agrichemicals were discovered and are increasing in our groundwater, as well as in surface waters (Kelly 1986; Cohen et al. 1984; Kross et al. 1990). It is also our great concern that these 3 agrichemicals may interact with increasing background of methyl mercury (HG) in this area (about 0.2 mg/Kg in wet weight in southeastern US) for unpredictable toxic effect. The soluble concentrations of mercury in Mississippi River (5.626 ug/L) and Pearl River ( 5.029 ug/L) were known to be very high in this area (Yang et aI. 1994). As a single chemical, ATR was known to exert its inhibitory effect mainly on photosynthesis by blocking the electron transport chain of phtosystem II. This resulted in the destruction of chlorophyll and cell death in plants (Solomon et al. 1996). MA interfered with the normal metabolism and growth of plants by mimicking phosphate in absorption, translocation, and metabolic pathway. MA is also considered to be toxic to animal for neurologic, reproductive, and gene function (Menzer 1991; Tomlin 1994). CPF is mainly toxic to animals for its irreversible inhibitory function to acetylcholinestrase (Menzer 1991; Sorrano et al. 1995). HG accumulated in organisms by formation of analog close to methionine for entry into amino acids and proteins. Upon binding to thiol-containing enzymes, the activity of the protein will be greatly reduced (Clarkson 1994). Conversion of methyl mercury into inorganic mercury resulted in increased hydrogen peroxide production and disrupted electron transfer in electron transport chains also (Lindqvist 1991; Clarkson 1994). Current reviews of atrazine (Brusick 1994), mercury compounds (Flora et aI. 1994), inorganic arsenic compounds (de la Rosa et aI. 1994), and organophosphosphate (Gollapudi et al. 1995), about the genotoxicological effects of those chemicals were inconclusive. Most of the laboratory tests showed no mutagenecity of those chemicals in the Salmonella mutagenicity test. The current experiment intends to use a more sensitive strain of Salmonella, TAI02 (Levin et aI. 1982), for more sensitive testing of those chemicals in solitary application or in mixed application with various combinations to those mesocosms.
Assessing Interactions of Multiple Agrichemicals by Using Bacterial Assemblages in a Wetland Mesocosm System
Year: Authors: Hwang H.M., McArthur N., Ochs C., Overstreet, Jr. K.
Seldom are microorganisms exposed to a single contaminant in natural environments. Instead, they are often exposed to combinations of contaminants simultaneously. The presence of other cations in the environment can affect the toxicity of heavy metals to microbes, as a result of competition with the cationic forms of the heavy metals for anionic sites on cell surfaces. In addition, the concentration and composition of dissolved and particulate organic matter present in the environment can influence the mobility and bioavailability of heavy metals and, thereby, their toxicity. Therefore, interactions between and among contaminants are likely to occur and may result in synergistic or antagonistic effects on microbial assemblages in the mesocosms. In this study, we examined the main and interactive effects of three commonly used agrichemicals and methyl-mercury, which commonly occurs as a background contaminant, on microbial metabolism in the sediments and water of a wetland mesocosm. Pesticides selected for this study were based on factors such as the application and volume of pesticide used in Mississippi, availability of their toxicology data, and our analytical capability for the chemicals. The three agrichemicals we used were atrazine (ATR), chlorpyrifos (CPF), and arsenate [as monosodium acid methanearsonate (MSMA)]. These three chemicals and a background contaminant (methyl mercury) was introduced into 66 experimental mesocosms in a center-point enhanced 2/\4 factorial design. The effects of the candidate contaminants on abundance and heterotrophic potential of wetland heterotrophic bacterial assemblages were monitored for a duration of 94 days, including 32 days after half of the mesocosms were redosed.
Pesticides in the Yazoo River and Bogue Phalia, February Through September 1996
Year: Authors: Dayama A., Coupe R.H.
A study of pesticides in the Mississippi River during 1991-92 by the U.S. Geological Survey (USGS) indicated that the Yazoo River, a tributary to the Mississippi River, was a major contributor of cotton and rice herbicides to the Mississippi River and subsequently to the Gulf of Mexico (Pereira and Hostettler 1993). In February 1996, the USGS, through its National Water Quality Assessment (NAWQA) program, began a study to determine the status and trends of water quality in the basin of the Yazoo River. As a part of this effort, two streams have been sampled biweekly for pesticides from February through September 1996. The two streams sampled were the Yazoo River near its mouth and the Bogue Phalia which drains a smaller subbasin of the Yazoo River (Figure 1). The Yazoo River Basin (YRB), Mississippi’s largest river basin, consists of about 13,000 square miles. It is divided almost equally betwa een lowlands in the Mississippi Alluvial Plain (commonly referred to as the Delta), an intensive agricultural area of mostly cotton, rice and soybean production, and the uplands, which generally consist of forests, pastures and small farms. In 1987, there were, 1,270,000 acres of soybeans ,760,000 acres of cotton, 176,000 acres of rice, 77,000 acres of grain sorghum, and 34,000 acres of corn harvested in the YRB. The YRB is sparsely populated with no major metropolitan areas (Coupe 1996). This paper presents the results of the analysis for pesticides in surfacewater samples collected from February to September 1996 from the Yazoo River and the Bogue Phalia.
Application of the MEPAS Model - Investigation of Lead Migration at the Camp Edwards Military Range
Year: Authors: Deliman P.N., Ruiz C.E.
This study investigates the potential migration of lead to groundwater resources from SARs at the Camp Edwards Military Reservation located near Cape Cod, Massachusetts. Both concentrations and time of arrival were determined for both vertical and horizontal migration of lead. Vertical migration consisted of computing the time for the lead to migrate to the surface of the groundwater aquifer. After arriving at the aquifer, horizontal transport to wells located at various distances from the source was calculated. The Multimedia Environmental Pollutant Assessment System (MEPAS) model was used to conduct this groundwater modeling study investigating the potential migration of lead from SARs at the Camp Edwards Military Range.
Interactive Effects of Multiple Agrichemicals in Wetlands: Design and Statistical Overview of a Mesocosm Experiment
Year: Authors: Libman B.S., Threlkeld S.T.
The disadvantage of two-level experimental designs is that they can not resolve curvilinear dose-response functions. A three-level design could resolve linear and quadratic slope components, but would require 81 treatment combinations. A more efficient design would be to use a single design point half-way between the low and high dose (centerpoint). The center-point would allow us to determine if there was departure from linearity (lack of fit). A center-point enhanced 2’ design is only 17 treatment combinations. These 17 combinations would allow us to determine the main and interactive effects of four chemicals and determine if there is departure from linearity. Another issue regarding design efficiency is replication. Replicating all design points in an experiment is costly and not necessary. For the experiment described below, the only replication used was 6 replicates of the center points. This is a 35 percent savings in experimental units over replicating all the design points (17+5 vs.17x2). To further increase saving in experimental units, replication can be completely omitted from the design. Error can be estimated from unreplicated designs by half-normal plotting (Daniel 1959). Our goal was to determine if replication is necessary in ecotoxicology experiments set at the mesocosm scale. Another issue we explored in this paper is how sampling of experimental units affects variability at future sampling times. Because experimental units are costly (or unreplicable) experimenters are often required to resample them. In mesocosms, sampling can cause unwanted variation. The sampling design used in this experiment allowed us to determine if sampling of mesocosms increased variation at a later sampling dates and how the time interval between resampling affected the overall variability. The goals of this paper are to: (I) determine the frequency of response variables that respond in a non-linear fashion, (2) compare error center-point error estimates to half-normal plot error estimates, and (3) determine the amount of variability introduced by sampling the experimental units.
Native Vegetation and Substrate Type in Wetlands for Wastewater Treatment
Year: Authors: Davis S.A., Holland M.M.
In the early 1990s, the Ecological Society of America proposed The Sustainable Biosphere Initiative (SBI) in response to a call from the scientific community and polieymakers to set priorities for the discipline. The response resulted in development of a framework for the acquisition, dissemination, and utilization of ecological knowledge (Lubchenco et al. 1991). The SBI focuses on the necessary role of ecological science in the wise management of resources for the maintenance of life support systems (Lubchenco et al. 1991). The SBI proposed three research priorities: global change, biological diversity, and sustainable ecological systems. After the successful launching of the broad SBI, the Freshwater Imperative (FWI) Research Agenda (Naiman et al. 1995) was envisioned as a more focused initiative concentrating on freshwater issues. The FWI agenda proposes establishment of long-term programs for freshwater research relating directly to improved watershed management and human sustainability. With the widespread misuse and alteration of watershed dynamics, watershed data acquisition is essential. This research project is connected to these agendas in that it examines biodiversity and sustainability of the native vascular plant community within constructed wetlands and allows the testing of indicators of anthropogenic stress within the vascular plant communities. The desired functions of the vascular plant community within constructed wetlands are multifold. The objectives here include not only maintenance of high water quality, but also continued sustainability of the regional watershed. If alien species are allowed to develop within wastewater treatment facilities, they could escape and influence the downstream plant community (Decamps 1996). Understanding of the life histories of native vegetation, rather than introduced species, is needed if biological diversity is to be sustained within the watershed.
Results of the 1996 NAWQA Fish Community Assessment in the Mississippi Embayment Study Unit
Year: Authors: Justus B.G., Kleiss B.A.
The U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program is designed to assess status and trends in the quality of the Nation’s water resources. The Program will eventually integrate physical, chemical, and biological data from about 50 study units across the Nation. The goal of NAWQA is to determine factors that affect water quality and to measure the extent of the effects on both national and regional levels. Biological assessments of fish, macroinvertebrate, and periphyton communities are planned at selected sites in each of the study units for a 2 or 3-year period. The purpose of this paper is to characterize fish communities assessed in the Mississippi Embayment study unit (MISE) for the first of three annual collections. In 1996, ecologists assessed fish communities from eight sites located on seven rivers in Arkansas, Louisiana, Mississippi, Missouri, and Tennessee; all of which lie partially within the MISE boundary (Figure 1). Two of the sites (the Bogue Phalia and the Cache River at Cotton Plant) had three reaches sampled to evaluate sampling consistency, and a total of 12 reaches were sampled. Five of the rivers and 10 of the reaches are located in the Mississippi Alluvial Plain Ecoregion. Of the remaining two streams, one is located in the Mississippi Valley Loess Plains Ecoregion and one is in the Southeastern Plains Ecoregion.
Environmental Estrogens: Potential for Reproductive Toxicity in Fish
Year: Authors: Benson W.H., Nimrod A.C.
Most environmental estrogens act by a similar mechanism as estradiol (E2). E2 induces its biological effects by binding to a protein, the estrogen receptor, and this steroid:receptor complex interacts with DNA to promote protein synthesis. However, most environmental estrogens have less affinity for the estrogen receptor, thus, less potency than E2. There are also some recognized indirect mechanisms of estrogenic activity such as interference with enzymes in the steroidal metabolic pathways or interaction at points along the reproductive axis upstream of the target tissue (e.g., hypothalamus or pituitary). Considering the role of sex steroids in the regulation of reproductive processes and development of reproductively competent organisms, xenoestrogens have the potential to be devastating to populations. In mammals, environmental estrogenic activity has been linked to reproductive disorder and disruption of developmental processes subsequent to exposure. Clearly, the survival of a species depends on successful development and reproduction. Reproductive toxicity may occur during larval development, or, because many of these compounds are designed to be resistant to degradation and -63- metabolism, they can be bioaccumulated and may compromise the successful maturation of the gonads in a later stage. This investigation describes the first year of a projcct, supported by the Water Resources Research Institute, in which the investigators sought to identify estrogenic compounds in channel catfish based on their ability to induce vitellogenin (Vg). Vg is a glycophospholipoprotein which serves as yolk precursor and is taken up by the ovary from the blood where it is incorporated into the developing oocytes and cleaved into yolk proteins. The overall research strategy is designed to test the hypothesis that the estrogenic activity of select chemicals results in reproductive toxicity.
Floodplain Fisheries Resources Under Tribal Jurisdiction of the Mississippi Band of Choctaw Indians
Year: Authors: Schorr M.S., Jackson D.C.
Choctaw Indian Reservation (ClR) lands near Philadelphia, Mississippi, encompass main channel and floodplain components of the upper Pearl River basin. This natural ecosystem establishes culturally important seasonal rhythms on the landscape, within which the Choctaw Indians orient their interactions with fish and wildlife resources. Preliminary consultation with management representatives (Joe Gairdinski, Mississippi Band of Choctaw Indians, personal communication) suggested that most fishing by Choctaw Indians on CIR lands occurs in the oxbow lakes for recreational and subsistence purposes. However, there is little published information on the fish assemblages in this section of the upper Pearl River basin, Our objective was to characterize tile fisheries resources of the Pearl River and its oxbow lakes (in particular) on CIR lands. This was identified by the CIR as an important first step in safeguarding and enhancing relationships between Choctaw Indians and the fisheries resources on their properties and, ultimately, integrating management orientations into overall natural resources programs on the reservation.
Issues and Conflicts in Reservoirs
Year: Authors: Barkdoll B.D.
New reservoir construction is meeting fierce resistance lately. The side-effects of reservoirs are being seen as environmental hazards. For example, the resettlement of indigenous people groups is said to have long lasting effects on their health and adaptability. Flora and fauna of a region can be changed by the inundation of an area. Wildlife can be altered and, in extreme cases, a species become extinct. The economy of a region changes due to both resettlement and to newly created recreational opportunities. Flooding patterns change upstream of the reservoir if sedimentation causes blockage of stream conveyance. This blockage also may prevent the spawning of some fish species. If this sediment aggradation becomes exposed during periods of low flow, then wind can carry the sediment to picnic and other recreational areas. Decreased sediment supply downstream of the dam also causes problems due to reduction in sediment supply. This reduction increases the river’s ability to scour river beds and banks, thereby causing the river to possibly change course. Transportation and recreation on reservoirs is reduced due to small clearance distances for boats and shoaling of harbors. Fish populations can diminish due to decreased storage capacity of the reservoir. Solutions must be found to these social issues for existing reservoirs if there is to be any hope for the future development of new reservoirs. With these conflicts before us, the fate of reservoirs, both existing and proposed, is in question. Should new reservoirs be planned and constructed, or should we remove existing ones? Perhaps we should manage existing reservoirs in a more environmentally sound manner and discourage new projects. These are the questions that our society, and we as engineers, will have to grapple with in the future. This paper reviews the mechanism of sediment deposition in reservoirs and lists some of the issues involved in chemical transport in reservoir sedimentation and the social effects of sedimentation. Finally some recommendations for the future are explored.
Mississippi Department of Environmental Quality Office of Land and Water Resources Water-Use Program
Year: Authors: Warner A.J.
The Mississippi Department of Environmental Quality, Office of Land and Water Resources’ (OLWR), Water-Use Program was initiated in 1992 to compile site specific freshwater withdrawal data from Mississippi’s aquifers. This withdrawal data represents a measurement of the stress applied to aquifer systems by pumping wells and is one of the critical sets of information used by the OLWR. In order to discharge its responsibilities, the OLWR requires this withdrawal data on an annual basis and withdrawals must be associated with specific wells, specific aquifers, and specific uses. On that basis, it was decided to expand the OLWR efforts to monitor groundwater withdrawals to aid in the Office’s ongoing hydrogeologic studies and to aid in water management decisions. The goal of the Water-Use Program is to gather existing withdrawal information from various sources and compile this data into a single database. To track these withdrawals, a computer database (The Mississippi Groundwater Withdrawals Database, MGWD) was created. A hard copy file was also created for each groundwater well identified by the name of its owner that would hold the documentation of the pumpage data that has been compiled.
The Development of Integrated Spatial Data for the Management of Water Resources in Mississippi
Year: Authors: O'Hara C.G., Katragadda S.
Different agencies and organizations that deal with water resources require similar data and information to be collected, developed, or compiled for various uses. A project is being conducted by the U.S. Geological Survey (USGS) to collect, integrate, and produce spatial-data resources for water management and protection in Mississippi. The purpose of this project is to develop a geographic information system (GIS) that will make integrated data resource management possible for water professionals in Mississippi. The spatial data layers will include aquifer outcrop location, altitude of the base of the aquifer units, location of index well-logs, location of wells with water quality data, location of public-supply wells, susceptibility of groundwater to surface and shallow sources of contamination, and general information about the quality of water in the aquifers in the State of Mississippi. The objective of this project is to produce a set of integrated data tools within a user-friendly GIS interface that will assist water-resource professionals in efficiently accomplishing specific tasks related to water resources. Most tasks fall into one or more of the following categories:<br> • Source-Water Management and Protection<br> • Infrastructure Development<br> • Prioritization of Activities<br> • Site Selection<br> • Emergency Response (to spills or contamination events)<br> • Permitting and Regulating Activities<br> • Water-Quality Monitoring<br> • Managing Information.<br>
An Analysis of Fish and Sediment Samples from Mississippi Delta Rivers
Year: Authors: Pennington K.
The results presented in this paper were developed as part of the USDA Natural Resources Conservation Service’s (NRCS) Delta Water Supply Study. The study was initiated by request to NRCS from the YMD Joint Water Management District and Delta Soil and Water Conservation Districts to determine the feasibility of stabilizing groundwater levels in the Mississippi River Alluvial Aquifer (aquifer). The issues of water supply and water quality in the Mississippi Delta are locked together by many relationships including aquifer level influence on baseflows in internal streams. Adequate baseflows are essential to a healthy stream environment.
Estimation of Trends in Surface-Water Characteristics for Hickahala and Peters (Long) Creeks of the Yazoo River Basin Demonstration Erosion Control Pr
Year: Authors: Runner M.S., Rebich R.A.
In 1985, the U.S. Geological Survey (USGS) began collecting data for the Demonstration Erosion Control (DEC) project in north-central Mississippi. The project is part of a multi-agency program for the planning, construction, and evaluation of measures to alleviate flooding and erosion in the Bluff Hills of the upper Yazoo River Basin. Since 1985, stream discharge data, sediment samples, and water-quality samples have been collected at selected sites in the DEC study area by USGS personnel, station observers, and automatic samplers. A 1993 investigation indicated possible trends in surface-water discharge, suspended-sediment concentration, and sediment discharge at some of the DEC sites (Rebich 1993). Further investigations at Hotopha and Otoucalofa Creeks indicated decreasing trends for flow-adjusted sediment discharge for both sites, despite the increasing trends in stream discharge for both sites (Rebich 1995). These results indicated possible changes in features within the basin that contributed to the decrease in sediment discharge. This report presents trend analyses for daily mean values of stream discharge, suspended-sediment concentration, and sediment discharge for Hickahala Creek near Senatobia and Peters (Long) Creek near Pope.
Measurement of Streamflow in the Lower Yazoo River Using an Acoustic Doppler Current Profiler, January-August 1996
Year: Authors: Manning M.A.
The Yazoo River in west-central Mississippi drains some of the nation’s richest farmland. Sediment and chemical loads from the basin are of great interest to scientists, as well as to the agricultural community because of the loss of topsoil and expensive agricultural chemicals. However, accurate sediment and chemical loads from the Yazoo River are not available because of the complexity in determining discharge from the Yazoo River near its confluence with the Mississippi River at Vicksburg. Except during periods of extremely low flow, backwater from the Mississippi River at Vicksburg, Miss., affects the stage and discharge of the lower Yazoo River. During medium to high stage on the Mississippi River at Vicksburg, the lower Yazoo River is greatly affected by a wedge of backwater that is forced into the Yazoo River channel. During periods when the Mississippi River is rising rapidly, water may flow in the upstream direction in all or part of the Yazoo River channel below Steel Bayou. This bi-directional flow makes it virtually impossible to measure streamflow in the lower Yazoo River using a conventional current meter. With the development of acoustic doppler current profiler (ADCP) technology, it has become possible to quickly and safely make accurate streamflow measurements in large rivers with complex flow conditions. Beginning January 1996, weekly streamflow measurements were made by the U.S. Geological Survey (USGS) by using an ADCP on the Yazoo River below Steele Bayou near Long Lake, Miss. This report summarizes the streamflow measurements and the procedures used by the U.S. Geological Survey to make those measurements.
Nutrient and Sand Removal Technologies Utilized in Dairy Manure Solids Separation
Year: Authors: Burcham T.N., Gill S.K., Moore R.B., Pote J.W.
While the removal of manure solids can improve the ability to land apply wastewater using irrigation methods, the dairy producer must now handle two separate waste-streams liquid and solid. This situation has agronomic, economic, and environmental implications to the dairy producer. This has prompted a research study by the Mississippi Agricultural and Forestry Experiment Station (MAFES) to explore the benefits, if any, associated with solids separation on dairy waste-streams. To achieve this research goal, a manure solids separation research facility was designed and constructed at the Bearden Dairy Research Center in Sessums, Mississippi. The manure solids separation facility (MSSF) consists of a mechanical screen separator (MSS), a gravitational settling basin (GSB), and a concrete storage pad. The MSSF was designed such that the wastestream could be routed serially through the MSS and GSB or through the GSB only. Effluent exiting the MSSF proceeds to the anaerobic first stage lagoon (part of a three-stage lagoon treatment system) for additional treatment. This paper discusses measurement procedures as well as solids and nutrient removal efficiencies for the first year of operation.
Influence of Climatic Water Balance and Soil Type on Work Days in Mississippi Forests
Year: Authors: Wax C.L., Pote J.W.
Weather is the primary control affecting the timeliness of timber and pulpwood harvest. Weather exerts its control on harvest operations primarily through the soil moisture regime. Field work when the soil is too wet, even if physically possible, results in serious damage to the soil structure and increased time required for an operation (Hassan and Broughton 1975). Soils that are too wet to support heavy equipment will be compressed and rutted during harvesting of trees. These physical alterations of soil lead to increased bulk density, loss of soil macroporosity, increased erosion, decreased availability of water, and potential loss of productivity (Rachael and Karr 1989; Guo et al. 1991; Karr et al. 1991). Therefore, the obvious advantage of the forest productivity stemming from the humid climate type is often offset by the excess rainfall resulting in soils that are too wet for harvest operations. The interaction between evapotranspiration, rainfall, and soil moisture storage influences tractability of soil and determines the number of work days for a specific soil, providing periods of time on both annual and monthly scales when harvest is limited or possible. This water balance aspect of the natural environment is governed by climate, and the temporal pattern of occurrence should become evident by analysis of the corresponding climate record. Therefore, the objective of this study is to establish the relationship that exists between climate and the pattern of work days in the state and then to provide guidance on the number of potential work days based on sets of probability levels. This information will be organized by soil type and location, both monthly and annually.
Crop Water Use in the Mississippi Delta
Year: Authors: Hendricks M.W.
Historically, agricultural water use information has been collected indirectly through producer interviews. Producers themselves seemed unaware of the actual volumes of water they required for crop or fish production. Water budgets developed for catfish ponds in Alabama in the early 1980s considered annual requirements to be as high as 80 inches (Boyd 1983). Interviews with catfish producers led the Mississippi Department of Environmental Quality to establish a permitted volume of 60 inches per year for catfish production. In contrast, computer modeling indicated that it was possible for established ponds in Mississippi to use as little as 15 inches per year (Pote et al. 1988).
Estimates of 1995 Water Use from the Mississippi River Alluvial Aquifer in Mississippi
Year: Authors: Stiles M., Pennington D.
A computer groundwater flow model of the alluvial aquifer is an important and necessary tool for this regional water use planning process. The US Geological Survey (USGS) has agreed to assist in the planning for the development of alternative water supplies by developing the computer model of the alluvial aquifer in a cooperative project \vith YMD, NRCS, and the Office ofLand and Water Resources (OLWR). One component needed for the development of the model is the best possible spatial and temporal estimates of water withdrawals from the aquifer. YMD is providing those estimates for each permitted well in the Delta as one part of their participation in the development of the model. This paper details the development of these water use estimates.
Effect of Controlled Water Table on Runoff Losses of Soil-Applied Chemicals
Year: Authors: Southwick L.M., Willis G.H., Fouss J.L., Rogers J.S., Carter C.E.
Management of water table depths with subsurface drains may improve the utility of these drains for decreasing the amounts of agrocbemicals lost from alluvial soils by way of surface runoff and leaching (Willis et al. 1991; Skaggs et aI. 1994). For example, if rain appeared imminent soon after pesticide or fertilizer application to the soil surface, the water table depth could be lowered to enhance inftltration and increase within-soil storage capacity, thereby decreasing runoff loss. Alternatively, if the pesticide and/or fertilizer were already incorporated into the soil surface, the water table could be maintained at some elevation above a subsurface drain line to retard agrochemical leaching below the root zone and thereby retain the chemical in the biologically active zone longer for utilization or degradation. This paper presents results from the first two years of a study on the effect of controlled water table on runoff losses of soil applied chemicals from Mississippi River alluvial soil in southern Louisiana. Due to the generation of a soil compaction layer during the field installation work, the subsurface drains exhibited an erratic influence on water flow. Therefore, we report here data only from the plots without subsurface drains.
The Fate of Hydrogen Peroxide as an Oxygen Source for the Remediation of Biologically Active Subsurface Treatment Zones
Year: Authors: White K.F., Hwang H.M., Zappi M.E., Qasim M.
Existing technologies are usually not effective at sites with contaminants of low water solubilities or those that are readily adsorbed to soil. Current delivery or recovery methods are also usually ineffective for contaminated unsaturated soils. Low hydraulic conductivities and local stagnant zones in unsaturated media inhibit the rates and ultimate effectiveness of most delivery or recovery technologies. Furthermore, some current recovery methods applied to the unsaturated zone require an underlying impermeable barrier that precludes their use at some sites. Another problem not addressed by current delivery and recovery technologies is the presence in some natural soils of preferred pathways of high conductivity separated by blocks of low conductivity. Delivery or recovery from such soils is limited by rates of diffusion through the soil matrix blocks to the preferred pathways (Murdoch et al. 1990).
Mississippi Delta Surface Water Quality, A Summary
Year: Authors: Pennington K.
The water quality survey portion of this study was designed to provide background data for existing water quality in the major interior waterways in order to predict how adding water to supplement flows will influence overall water quality. The objective of the sampling program was to chart water quality changes in response to the currently existing changes in stream flow and predict or monitor how proposed managed additions to stream flows will influence water quality. This effort was started in October of 1993 and is funded through October 1996. Sampling through major hydrologic events was not possible due to resource limitations. Monthly sampling at specific sites was chosen to prevent the bias that limited event sampling could induce. Accurate background pictures cannot be developed without dry period data, so all months were sampled. Ideally, monitoring would continue indefinitely to establish long term patterns or trends in water quality and monitor the effects of implemented practices. Realistically, all studies involve completion time tables and budget constraints, both of which are not conducive to permanent monitoring efforts. The augmentation and increased use of surface water to maintain flows and take pressure off the alluvial aquifer will potentially benefit agriculture and aquatic organism populations, as well as safeguard water quality and supplies for urban areas and wildlife. Stream flow augmentation may be a practical solution to the problem of water supplies in the Delta.
Modelling Quantity and Quality of Overflow from Aquacultural Ponds
Year: Authors: Pote J.W., Wax C.L., Tucker C.S., Kingery S.K.
Fish culture, as is true of all forms of food animal production, generates wastes. Depending upon the nature of the culture system, some or all of those wastes will be discharged into surface water supplies. Although aquaculture has developed into a significant food animal production industry in the United States, relatively little research has been conducted to describe and quantify the wastes generated during culture or to assess the effect of aquaculture waste discharge into the environment. This has led to uncertainty and concern about the extent to which waste discharge from aquaculture facilities may affect receiving bodies of water. These concerns have been exacerbated by an uncertain regulatory climate in which government agencies have at times promulgated regulations with little knowledge of the nature of aquaculture discharges or their environmental effects. The following study was undertaken to characterize effluents from channel catfish Ictalurus punctatus culture ponds in northwest Mississippi. A climatological model of pond water budgets was used to examine the role of two different water management practices on current waste discharge produced. Combining the modelled volume of overflow with selected water quality measurements produced the data for the analyses. Average and extreme conditions were determined seasonally.
Storm Drain Replacement Using a Salt Marsh in Biloxi, Mississippi
Year: Authors: Melby P.O., Cathcart T.P., Moncreiff C., Caldwell J.D.
A wetland is defined by 40 C.F.R. (Code of Federal Regulations) 230.3 as "those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas." A tidal salt marsh is simply a marsh that is within the tidal range of an ocean. This project began in the fall of 1991. A group of seniors from the Landscape Architecture Department at Mississippi State University were invited by the City of Biloxi, Mississsippi, to survey the Mississippi Gulf Coast area and offer suggestions and improvements that could be made in order to increase tourism into the coastal area. One of the suggestions was to remove from the beach storm sewers that run from the sea wall out into the Mississippi Gulf Coast Sound area. Many visitors and residents mistakenly believe that the storm sewers conduct municipal waste. The appearance of the storm sewers, and this mistaken perception as to their function, has diminished the attractiveness of the beaches. The Landscape Architecture students suggested that the storm drains be replaced by a more natural "wetland" type drainage system. This system would still allow the storm water runoff to be routed into the Gulf, while offering a more aesthetically pleasing beach area. Design problems associated with wetland restoration are, in general, relatively uncomplicated and have been implemented successfully in other locations. Extensive literature on the establishment of Spartina altemiflora marshes on sand-dominated dredge spoil along the North Carolina coast is an additional resource of project information. East coast and Gulf of Mexico marshes seem to be similar in structure and function. Thus, much of the information on transplanting of S. altemiflora in North Carolina should be applicable to its estblishment in Mississippi. A unique feature of this particular problem is the small size of the system which was constructed. Patterns of beach use by residents and visitors mandated that the salt marsh remain a minor feature on the beach landscape. The small size (- 1/2 acre) made the salt marsh vulnerable to substantial disruption by events that would represent minor perturbations in a larger system. The following represents a chronicle of the first year of this project. It should be noted that this is very much a "project in progress" and has been a significant learning experience for all of the participants.
Tupelo and Corinth - Examples of Groundwater Management Practices in Two Northeastern Mississippi Communities
Year: Authors: Jennings S.P.
Tupelo and Corinth are metropolitan centers in northeastern Mississippi that have in recent decades experienced significant population and industrial growth with accompanying increases in water use. Long-term declines in water levels in public water-supply wells at Tupelo, in Lee County, and at Corinth, in Alcorn County, resulted in serious concerns in each community for the viability of water supplies to sustain high growth rates. The mehtods by which these communities have each dealt with water-supply concerns provide interesting and useful lessons in water management.
Groundwater Withdrawals from the Mississippi River Alluvial Aquifer: A Weekly Case Study of Influencing Factors
Year: Authors: Neill S.W., Giger C.A.
Most of the conclusions about the changes in the water levels in the Mississippi River alluvial aquifer are based on data collected twice a year, spring and fall. As these conclusions could possibly be based upon inaccurate data due to variability in recharge or other factors as cited above, a study was initiated to monitor a number of wells in Washington County on a weekly basis to gather data indicative of the movement of water levels and the causative events.
The Study of Naturally Occurring Radioactive Materials Norm in Waters of the State of Mississippi
Year: Authors: Aceil S.M.
The Naturally Occurring Radioactive Materials originate from the following sources: (1) Cosmic or extra-terrestrial; (2) Terrestrial; and (3) Technologically Enhanced Natural Radiation (TENR). The surfce of the earth is bombarded by cosmic-rays continuously. In the U.S., the average annual whole body dose equivalent from cosmic-rays is estimated to be about 45 mrem or 0.45 mSv with a range of 0.30 mSv in Hawaii and Puerto Rico to 1.30 mSv in Wyoming. In Mississippi, this value is estimated to be 0.40 mSv (Kaplan 1965; Kathern 1984).
The Need for Wellhead Protection: A Review of Ground Water Quality in Mississippi and its Impact on Public Water Supplies
Year: Authors: Ingram R.B., Crawford J.L.
In Mississippi, over 90% of Mississippians drink ground water daily from public water supply wells. Although ground water from those wells is considered safe through routine testing by the Mississippi Department of Health (MSDH), background levels of man-made chemicals are routinely found in our drinking water sources throughout the state. Are those levels increasing, decreasing, or staying the same? Currently, historic water quality data is insufficient to make a determination; however, our use of man-made chemicals continues to increase. Also increasing are the number of sites where contaminant releases to ground water are suspected or confirmed. A relatively new program, Wellhead Protection is designed to identify and manage potential contaminant sources in areas near public water supply wells and offers a significant opportunity to reduce the threat of contamination to our public water supplies.
Herbicides in the Surface Water of the Yazoo River Basin, Mississippi
Year: Authors: Coupe R.H.
The U.S. Geological Survey (USGS), through its National Water Quality Assessment program, is studying the effect herbicides have on water quality in the Yazoo River Basin (YRB; Figure I). As part of the planning process for the study, an analysis of available herbicide data was performed. This paper presents the results of this evaluation for the herbicides atrazine, alachlor, metolachlor, prometryn, cyanazine, fluometuron and molinate. Where the data were sufficient, herbicide data for the YRB were compared to data for the Midwest. Very little work has been done on a regional scale to understand the characteristics of herbicide transport in the YRB in Mississippi. The YRB, Mississippi’s largest river basin, consists ofabout 13,000 square miles (Figure 1). It is divided almost equally between lowlands in the Mississippi Alluvial Plain (commonly referred to as the Delta), an intensive agricultural area of mostly cotton, rice, and soybean production, and the uplands which generally consist of forests, pastures, and small farms. The YRB is sparsely populated, with no major metropolitan areas. In 1987, there were 760,000 acres of cotton, 176,000 acres of rice, 1,270,000 acres of soybeans, 34,000 acres of com, and 77,000 acres of grain sorghum harvested in the YRB.
The Emergence of Mayflies, Stoneflies, and Trichoptera of the Leaf River as Related to Water Temperature and River Discharge
Year: Authors: Phillips P.A., Howell F.G.
The objectives of this study are to: (I) demonstrate generalized patterns of emergence of the members of each of three aquatic insects orders (mayflies, stoneflies, and caddisflies), and (2) describe the relationship between the emergence of members of these orders, river discharge and seasonal, water temperatures of Leaf River near New Augusta, Perry County, Mississippi. The combination of these three aquatic insect orders are often referred to as the "EPT" group and are often used in the evaluation of the ecologic health of a particular water body. The information presented here will be useful in determining life histories, coordinating more accurate procedures for sampling aquatic insects, and demonstrating the natural variation associated with the biologies of these three insect groups. To our knowledge, a study of this type has never been conducted in south Mississippi. Emergence of aquatic insects in temperate latitudes is known to be regulated by photoperiod and other environmental factors as such as temperature (Beckett 1982; Masteller 1993). While our larger project is focused on species and their individual emergence patterns as affected by water temperature and other natural variables in this section of the Leaf River, this paper will serve to document the relationships between water temperature, river discharge, and the seasonal emergence of members of these orders in this stretch of the Leaf River. This sampling for this study was begun in May 1994 and ended in September 1995.
Comparison of Nitrogen and Phosphorus Dynamics of Swine Lagoon Effluent and Fertilizer Based Forage Systems
Year: Authors: Adeli A., Varco J.J.
Land application of animal wastes and recycling nutrients through the soil-plant system has been a commonly accepted method of disposal. With the current interest in sustainable agriculture, recycling of nutrients such as N and P through land application of animal waste is a viable alternative to conventional fertilizer. Depending upon conventional fertilizer costs, animal wastes can be used as a source of plant nutrients (Wilkenson 1979). Forage crops have been shown to respond favorably to swine lagoon effluent. In research conducted by Westerman et al. (1983) to determine the effects of swine effluent on tall fescue yield, it was found that anaerobic swine effluent substantially increased tall fescue yield over inorganic fertilizer. According to Westerman et al. (1983), ’Coastal’ bermuda grass responded favorably to anaerobic swine effluent. Anaerobic swine effluent at rates of 335, 670, and 1370 kg N/ha resulted in respective yields of 10750, 14230, and 15810 kg/ha. In another study utilizing ’Coastal’ bermuda grass, Burns et al. (1985) found that anaerobic swine effluent resulted in positive uptake of N and P with increased application rate. Swine lagoon effluent has been shown to increase the fertility status of soils. King et al. (1990) observed that swine lagoon application equivalent to 0, 111, 221, and 442 kg P/ha increased levels of extractable soil P 85, 230, 320, and 450 mg/kg, respectively. Elevated nitrate-N content in the soil profile can occur from swine lagoon effluent as well. According to King et al. (1990), in research involving three rates of swine effluent equivalent to 335, 670, and 1340 kg N/ha, there was a significant increase in nitrate-N below 60 cm with the concentration reaching a peak of 35 mg/kg at 90 cm. The check, low, and medium rates of application never exceeded 5 mglkg at any depth. In research conducted by Sutton et al. (1978), downward movement of nitrate-N and P in the soil profile of plots receiving swine waste and fertilizer was studied. It was observed that accumulation of P occurred in the soil surface. There was no evidence of P leaching in the soil and, in most cases, available P concentrations in the soil reflected the amount of P in the swine waste applied to the soil. The greatest movement of nitrate-N as induced by the highest nitrate-N concentration was with inorganic fertilizer. Since N and P in lagoon effluent are of prime importance agronomically and environmentally, the proper management of swine lagoon effluent must be determined to improve crop production and to prevent degradation of water quality. Given this background, the objective of this study was to determine the effects of swine lagoon effluent rates on N and P uptake by forage grasses and movement of these nutrient in the soil profile relative to inorganic fertilizer.
Bioremediation of Low Level PCP and PAHS Contaminated Water Using Biofiltration
Year: Authors: Roark A., Wasson L., Diehl S.V., Borazjani A.
The objectives of this study are to optimize a biofiltration system that contains a highly efficient PCP and PAHs degrading bacteria for commercial application. Optimization will be done in the laboratory and involve maintaining the flow rates at commercial levels, increasing the efficiency of the system with higher cell densities, and testing PCP and PAHs in the same wastewater, since they are often mixed in an industrial setting. At the end of the study, a small-scale biofiltration unit, consisting of the most efficient parameters as determined by laboratory studies, will be tested at a commercial facility in the field. At this site, the retention volume to flow rate for their pump-and-treat system is 10:1, while the PCP concentrations average at 2 ppm.
Modeling Water Transport in a Silt Loam Soil of the Southern Mississippi Valley Silty Uplands
Year: Authors: Johnson A.B.
There is increasing interest in the agricultural commwtity in using models to guide the application of water and chemicals to soil and crops and subsequently predict the fate of these elements in the environment. Practical management options for reducing contaminant transport in the soil profile have traditionally been identified on the basis of site-specific experimental results. It might not be possible in all cases to extend the results from a small number of research situations to all conceivable scenarios. Furthermore, large-scale field sampling programs designed to determine solute and water transport in the soil profile are too expensive (Hutson and Wagenat 1993 ). Since the number of variables and/or combinations of variables impacting solute and water transport are large, an indirect method such as simulation modeling can be employed as a surrogate for experimental observations.
Development of DNA Fingerprints for Selected Shellfish-Borne Microbial Pathogens Using the Arbitrarily Primed Polymerase Chain Reaction (AP-PCR)
Year: Authors: Smith, III A.L., Vickery M.C., Bej A.K.
The AP-PCR fingerprinting method has successfully been applied for rapid and reliable identification of microbial pathogens such as Staphylococcus aureus (Welsh and McCleland 1990), Lactococcus lactis (Cancilla et aI. 1992), Frankia (Sellstedt et aI. 1992), Legionella pneumophila (van Belkum 1993; Gomez-Lus et aI. 1993), Campylobacter (Giesendorf et aI. 1993), Rhizobium (Bruijm 1992), Actinobacillus (Hennessy et a1. 1993), Clostridium (McMillin and Muldrow 1992), and Escherichia coli (p. Lett and A. Bej unpublished). This procedure takes a maximum of 3 days to complete. However, this approach has not been applied in shellfish borne microbial pathogens such as V cholerae, V parahaemolyticus, V. vulnificus, and V. mimicus. In this study, we have attempted to optimize the AP-PCR methodology to generate DNA fingerprints for selected strains of shellfish borne microbial pathogens.
Impaired Reproduction in the Fathead Minnow Following Chronic Exposure to Contaminated Sediments
Year: Authors: Benson W.H., Suedel B.C., Dillon T.M.
The purpose of this investigation was to evaluate the relationship between reproductive effects and polychlorinated biphenyl (PCB) tissue concentrations resulting from exposure to contaminated sediments from an inland waterway. Such "residues-effects" data are infrequently (ca., 6%) reported in the literature for fish or other aquatic organisms (Dillon 1984). However, these types of data may be valuable when interpreting the biological significance of contaminant tissue concentrations in field-collected animals.
Transformation of Bacillus Subtilis into Hydrocarbon-Resistant Bacillus
Year: Authors: Yang W.H., Yang J.R.
Studies of microbial degradation of pollutants have provided much critical information needed for ex situ waste treatment and for in situ bioremediation (Hinchee et al. 1994; CISB 1993). A marine bacteria, Acinetobacter calcoaceticus RAG-1 was identified as an oil-degradation microorganism in an earlier study (Reisfeld et al. 1972; Rosenberg et al. 1979a, b; Shabtai et al. 1985), and actively applied for bioremediation of the beaches in Alaska after the 1989 Exxon Valdez oil spill. Several other naturally occurring bacteria of the genus Pseudomonas were also discovered which utilize oil as their carbon energy source (Harvey et al. 1990). In this study, we report the discovery of another important soil bacteria, B. subtilis, which can be transformed with, or fused with the plasmid, pTV1Ts to obtain different capabilities to catabolize and degrade petroleum hydrocarbons.
The Fate of Surfactant During Biological Treatment of Contaminated Soils
Year: Authors: Thomas T., Hwang H.M., Qasim M., Zappi M.
This study is designed to determine the fate of a nonionic surfactant in heterogeneous subsurface environments. Because soil is one of the most poorly defined variables that affect in-situ bioremediation rates, this study will be performed on six different soil-types designed to represent the diversity of soils found in nature. It is anticipated that the behavior of Tween 80 in soil is strongly related to soil-type. By adding a surfactant to the soils or subsurface surroundings, this addition enhances the biodegradation process by increasing the bioavailability of the contaminates to the microorganisms.
Selection and Planning of Best Management Practices (BMPs) on the Mississippi Delta MSEA Project
Year: Authors: Parkman J.S.
The Management System Evaluation Area (MSEA) project includes the study of three watersheds that include oxbow lakes. The chosen lakes are: (I) Deep Hollow-Leflore County, (2) Beasley Lake-Sunflower County, and (3) Thighman Lake-Sunflower County. One of the major goals of this project is to identify, implement, and evaluate best management practices which have potential for use in the Mississippi Delta. A best management practice is the physical application of land and water management knowledge with the goal of protecting soil and water resources.
Automated Operation of Water Table Control Systems for Water Quality Management
Year: Authors: Fouss J.L., Rogers J.S., Willis G.H., Southwick L.M., Carter C.E.
The primary purposes of water table control are to minimize the time of excess or deficit soil-water conditions in the root-zone and to maximize the utilization of natural rainfall, thus minimizing the amount of subirrigation water required from external sources. Water table management technology has also begun to be used to improve water quality. Controlled-drainage practices have been developed in the Atlantic Coastal 140 Plains region (Gilliam et al. 1985; Deal et al. 1986) for reducing nitrogen and phosphorus levels in surface/subsurface effluent from agricultural lands. Successful water table control on a large field scale has been reported by Fouss et al. (1989, 1992) for an alluvial soil in the lower Mississippi Valley when subsurface conduits were used for the dual purpose of controlled drainage and subirrigation. Water table management has a high potential for achieving maximum crop production, water use efficiency, and improved water quality if properly controlled to compensate for changes in weather conditions. Determining when changes are needed in controlled-drainage and subirrigation to optimally manage the water table depth is a major problem for farmers, especially in coastal areas with fme textured soils. In the lower Mississippi Valley, frequent rainfall events can cause large variations in water table depth because of the small, 3 to 8%, drainable soil porosity. Rainfall probability information included in daily and 7-day forecasts issued by the U.S. National Weather Service can be useful to aid the farmer in making management decisions in anticipation of predicted weather changes (Fouss and Willis 1994). This paper presents field test results and performance evaluations for various methods of water table control during the 1995 growing season in an alluvial soil of the lower Mississippi River Valley.
Relative Contribution of Photolysis and Microbial Degradation to Chloroanilines Removal in Estuarine Water
Year: Authors: Hwang H.M., Evans G., Moore Q., Slaughter L.
p-Chloroaniline was photolyzed to produce photoproducts such as 4-chloronitrosobenzene and 4-chloronitrobenze (Millie and Crosby 1983). Photoproducts of aniline in natural water included azobenzenes (Zepp et aI. 1981). The photoproducts are subject to further photolysis and biodegradation, via dechlorination and oxidative processes with ultimate mineralization to CO, (Matsumura 1982). The attenuation of UV irradiation by dissolved organic compounds and suspended particulates are expected to result in lower photolysis rates for chloroanilines in natural waters relative to distilled water. However, photosensitizers present in natural water can accelerate photolysis rates of certain compounds (Larson et aI. 1989). The photodegradation of anilines was strongly enhanced in the presence of riboflavin at 5 uM, assumably due to the sensitized photolysis reaction (Halmann 1996). Thus for assessment of persistence of selected organic contaminants, it is essential that we understand the kinetics and mechanisms of photolysis and biodegradation of the contaminants in a given ecosystem. The objectives ofthis study are to review the previous data and determine the relative contribution of photolysis and microbial degradation to removal of chloroanilines, as the two processes significantly affect their fate in estuarine water.
Improvement of Reservoir Simulation Processes in the Hydrologic Simulation Program Fortran (HSPF) Watershed Water Quality Model
Year: Authors: Deliman P.N., Glick R.H.
The overall objective of this study was to develop an improved reservoir simulation capability for the comprehensive watershed water quality model HSPF. To accomplish the objective, the study was segmented into two phases. The first phase, which is discussed in this paper, involved implementing CE-QUAL-W2 on the Conowingo Reservoir and calibrating the model with flow and temperature data for selected years. Following the completion of the first phase, the developed CEQUAL- W2 model will have selected nutrients added to the simulation, sediment transport, and the estimated value of improvements of the HSPF RCHRES module will be determined.
Application of Hazop Study on Water Treatment Plant
Year: Authors: Yang P.C.
A hazard is an inherent physical or chemical characteristic that has the potential for causing problems. A hazard evaluation is an organized effort to identify and analyze the significance of hazardous situations associated with a processor activity. Hazard are used to pinpoint weaknesses in the design and operation of facilities that could lead to accidental chemical release, fifes, or explosions. Hazard evaluation studies usually focus on process safety issues, like the acute effects of unplanned chemical releases on plant personnel or the public. These studies complement more traditional industrial health and safety activities. Although hazard evaluation studies use qualitative methods to apply potential equipment failures and human errors that lead to accidents, the study also can highlight gaps in the management system of an organization’s process safety program (McJilton 1996). There are several synonyms for hazard evaluation such as process hazards analysis, process hazards review, process safety review, process risk review, and include hazard analysis. In my opinion, the process is similar to a risk assessment technique; both techniques are not to make final design and only make suggestion to the administrator. There is another process called risk management.
Design and Construction of a Research Facility to Compare Mechanical and Gravity Settling for Dairy Manure Separation
Year: Authors: Burcham T.N., Withers, Jr. F.T.
While the removal of manure solids can improve the ability to land apply wastewater using irrigation methods, the dairy producer must now handle two separate wastestreams, liquid and solid. This situation has agronomic, economic, and environmental implications to the dairy producer. This was the catalyst to establish a manure solids separation research facility at the Bearden Dairy Research Center in Sessums. Mississippi.
A Progress Report on the Off-Site Movement of Nutrients from Runoff Plots Treated with Swine Lagoon Effluent
Year: Authors: Burcham T.N., Wren D.G., Varco J.J.
During fiscal year 1995-96, eight runoff plots were installed at a commercial swine production facility located in Crawford, Mississippi. Each research plot is equipped with a sequential wastewater sampler (American Sigma Model 800 SL) controlled by a central host computer. Plots were paired; that is, one plot from each pair was equipped with a HS-flume and flowrate measurement instrumentation, while the other plot in the pair was a "slave" under control of the flume-equipped plot. The instrumented and non-instrumented plots will be referred to as master plots and slave plots, respectively. A weather station was placed on the site to provide correlation between climate, runoff, and nutritient movement. Individual plot instrumentation and the weather station are monitored by a distributed data acquisiton system driven by a notebook sized personal computer (the host). Remote Sensor to Computer Interface (RSCI) modules allow analog input signals to be digitized and transmitted to host computer. The entire system is powered by a 12-volt deep cycle batteries, so that AC power outage does not affect the operation of the system. The instrumentation system is controlled using object oriented Windows-based programming and, thus, provides real-time monitoring of flowrate and weather conditions. A detailed description of the apparatus can be found in the 1995 Mississippi WRRI Proceedings (Burcham and Wren 1995).
Water Blending in Commercial Catfish Ponds
Year: Authors: Cathcart T.C., Pote J., Kingsbury S.
Although the results from the study by Tucker and Steeby (1995) were not encouraging, interest in this approach and ancedotal reports about its efficacy continued to abound. The present study represents a repetition of the work by Tucker and Steeby with three important differences. First, this work was carried out in commercial catfish production ponds rather than research ponds. Second, the blender design differed from the design used by Tucker and Steeby. Finally, the placement and orientation of the blenders was different.
Overview of an Investigation of the Location and Depth of Water-Bearing Sands in Jackson County, MS
Year: Authors: Strom E.W., Oakley W.T.
Jackson County, located on the Gulf Coast in southeastern Mississippi, is experiencing rapid economic and industrial growth. Continued growth in the area depends on the availability of an adequate supply of water. In 1994, the U.S. Geological Survey (USGS), in cooperation with the Jackson County Board of Supervisors, began an investigation to compile information on the location and depth of water-bearing sands and intervening clays in Jackson County. This information is beneficial to city planners, engineers, water managers, water-well contractors, real estate developers, industries, and consultants, as well as to scientists investigating the nature and distribution of the sediments. The location and depth of sand and clay intervals were determined from selected well logs in Jackson County, Mississippi. This paper presents an overview of the results and examples of the various formats in which the data were presented in the report, "Location and depth of sand and clay intervals in Jackson County, Mississippi" (Strom and Oakley 1996).
Some Characteristics of the Upper Sunflower River Under Low Flow and Flow Augmentation Conditions
Year: Authors: Pennington D.
Base flows of Delta streams have been declining since 1970. Streams in deeper channels are hydraulically connected to the Mississippi River Alluvial Aquifer. Declining levels in the alluvial aquifer are resulting in a parallel reduction in stream base flows. Streams recharge the aquifer during high flows and the aquifer feeds base flows for the streams during very low stages and flows. Low stream base flows threaten the violation of water quality standards and viable wildlife habitat. Identification and development of alternative water supplies to be used to augment low stream flows is a major activity of the YMD Joint Water Management District. To efficiently plan for the development of alternative supplies of water requires that we understand how added water will behave in the stream channels of the Delta. In 3 of the last 4 years, YMD has augmented low flows in the Sunflower River to monitor responses in stream flows and water quality. The objectives of the augmentation tests were to: (I) measure stage transmission velocities, (2) measure transmission efficiencies, (3) measure velocity of movement of added water, (4) calculate volume of water in channels at low flow, (5) monitor changes in water quality, and (6) gain operational experience.
Estimating Daily Water Use in the Mississippi Delta
Year: Authors: Pennington D.
Water level declines in the Mississippi River Alluvial Aquifer have resulted from heavy use of that aquifer by agriculture for row crop irrigation, flooding of rice fields, and maintaining levels in catfish ponds. If aquifer water levels are allowed to continue to decline, the aquifer may eventually be destroyed and an incredibly valuable natural resource of the region would be lost. To prevent this loss and its staggering impact on the environment, agriculture, and the economy of the Delta, the YMD Joint Water Management District (YMD) and Area 4 Soil and Water Conservation Districts have undertaken a project, with the technical assistance of the Natural Resources Conservation Service (NRCS), to evaluate the feasibility of developing alternative water supplies for the Delta regIon. To complete the planning for alternative supplies, two major efforts were identified that would need water resource information on a daily or monthly basis. The daily information was needed for the development of an alluvial aquifer computer model and to assess the possible impacts of transporting water in interior streams of the Delta on flood carrying capacity. First, a computer model of the alluvial aquifer is an important and necessary tool for this regional planning process. Plans for conservation programs and new water supplies will be tested to see if their implementation would stop the overdraft of the alluvial aquifer. The US Geological Survey (USGS) has agreed to assist in the development of the computer model of the alluvial aquifer in a cooperative project with YMD, NRCS, and the Office of Land and Water Resources (OLW) of the Mississippi Department of Environmental Quality. One component needed for the development of the model is the best possible spatial and temporal estimates of water withdrawals from the aquifer. Daily water use was needed so that YMD can provide monthly estimates of water pumped for each of the 12,500 permitted wells in the alluvial aquifer. The results of monthly water use by individual wells is presented in Stiles and Pennington (1966). Second, importing water from the Mississippi or Yazoo River into the Sunflower River system is one new supply of agricultural water being evaluated. This option will place flows into the Bogue Phalia, the main channel Sunflower River, and the Quiver River during summer irrigation months. These channels already provide drainage and flood stage control for the region. Placing additional flows into these channels will impact channel needs to maintain a given level of flood protection. The Corps of Engineers (Corps) is currently evaluating flood channel needs in the Sunflower Basin. Their analysis of flood protection must now include the impact of using those channels for the dual purposes of flood control and water supply. An estimate of flows that may be introduced into the channels by possible agricultural water supplies is needed for the Corps to complete that analysis. The results of the flow analysis provided to the Corps are provided in another paper by Pennington and Stiles (1996). Both of the described projects need water use information over daily or monthly time periods. Very little organized data is available on daily water use in the Delta. Research may report daily crop water requirements or total annual water use (Hendricks 1996), but these data do not present short term water use information, nor consider the number of acres watered in the Delta, or the impact of individual management styles ofwater management. The water data needs required a general broad based integrator of the many individual factors that each influence water use in the Delta.
Preliminary Estimates of Water Importation Requirements for the Sunflower River Bsain
Year: Authors: Pennington D., Stiles M.
Importing water from the Mississippi or Yazoo River into the Sunflower River system is one option being evaluated. This option will place flows into the Bogue PhaIia, the main channel Sunflower River, and the Quiver River during summer irrigation months. These channels already provide drainage and flood stage control for the region. Placing additional flows into these channels will impact channel needs to maintain a given level of flood protection. The Corps of Engineers (Corps) are currently evaluating flood channel needs in the Sunflower Basin. Their analysis of flood protection must now include the impact of using those channels for the dual purposes of flood control and water supply. An estimate of potential flows that will be introduced into the channels by possible agricultural water supplies is needed for the Corps to complete that analysis. This work reports the preliminary estimates of those flows.
Mechanisms and Control of Herbicide Loss in Agricultural Runoff of the Mississippi Delta
Year: Authors: Shaw D.R., Webster E.P., Murphy G.P., Kingery W.L., Boyette M., Coupe R.H.
As with other intensively farmed regions of the U.S., nonpoint-source contamination of surface water is a primary concern for the region of Mississippi commonly known as the Delta. This alluvial plain is one of the largest contiguous agricultural areas in the U.S. Nearly 800,000 ha of cotton and soybean are farmed on soils that are susceptible to leaching, sediment erosion, and runoffloss of agrichemicals to surface waters. The Delta is drained primarily by the yazoo River, a major tributary of the lower Mississippi River, and its basin tributaries. A number of tillage and crop production programs have been suggested to reduce sediment and pesticide losses in runoff. No-till programs can reduce sediment loss by as much as 91% (Hairston et al. 1984). However, producers throughout the region, and particularly in the flat, poorly drained soils of the Delta, have been reluctant to adopt strict no-till systems because of difficulties in planting, stand establishment, weed control, and crop management. A primary objective of Delta producers is to facilitate movement of water away from land by means of raised beds, water furrows, and drainage systems, since poor internal drainage and water-logged soils severely limit yield potential. Thus, reducing sediment and/or pesticide movement in surface runoff is not conducive to normal crop productions practices in the Delta. In addition, changing tillage or cropping practices to control sediment movement in runoff can have variable effects on herbicide losses. Some research has shown that herbicides in runoff decrease with a shift to no-till systems (Baker et al. 1978), while others have shown increases (Shaw et al. 1992). Similarly, use of a cover crop can decrease (peterson et al. 1988) or increase (Banks and Robison 1986) herbicide concentrations and/or seasonal losses in runoff. Thus, in many instances shifting to a system that reduces sediment load in runoff may actually increase herbicide movement and vice versa. Another system that has been evaluated from a sediment control standpoint is vegetative filter strips. These can be planted at intervals in the field or as buffers on turn rows at field edges. These strips are typically 5-10 m wide and composed of perennial, non-invasive grasses such as tall fescue. Filter strips can reduce sediment load by as much as 75% (Webster and Shaw 1996) and nitrates by 73% (Dillaha et al. 1989a, b). Vegetative filter strips have also been effectively used to trap sediments, nutrients, and microbial contaminants from feedlot runoff (Young et al. 1980). Filter or buffer strips have been quite attractive to some Delta crop producers in that conventional tillage can still be conducted, thus allowing improved crop and water management in the field, while at the same time filters trap suspended solids, thus improving the overall quality of water leaving the field. To fully develop recommendations on controlling herbicide movement in runoff from Delta crop production systems, a complete assessment of current water quality from a herbicide standpoint is needed. Some studies have been done in Arkansas (Lavy et al. 1992) on lakes and waterways, and others have conducted assessments on the Mississippi River and its tributaries (Goolsby et al. 1993; Pereira and Hostettler 1993). Similar, but more detailed, assessments are needed in Mississippi to establish a baseline ofresidues currently present in surface waters of the Delta.
Biochemical and Population Effects of Long-Term Mercury Exposure in Largemouth Bass (Micropteris Salmoides) and Channel Catfish (Ictalurus Punctatus)
Year: Authors: Schlenk D., Perkins E.J., Wolford L., Dunnam G., Palmer A.
The occurrence of mercury in edible fish throughout the United States has caused widespread concern about potential hazardous effects to humans consuming mercury-laden fish. In recent years, fishery surveys of the lower Ouachita River have discovered levels of mercury exceeding the US FDA advisory limit of I mg/g in large predatory fish such as the largemouth bass and channel catfish (Nix et al. 1992). Fillets of mature largemouth bass collected from Woodard Lake, an ox-bow lake of the lower Ouachita river (3 mi NE of Camden, AR), possessed residues of mercury up to 1.5 ppm. The source of mercury and the effect of these residual levels in fish is unknown. The impact to human health has been the predominant endpoint in studies designed to examine the effects of mercury. However, the impact on the environment, or specifically, on fishery populations has not been adequately addressed. One way to measure the sublethal effects of metals such as mercury on aquatic organisms such as fish is to determine whether fishery populations with excessive mercury residues were experiencing biochemical stress. Metallothioneins (MTs) are low molecular weight proteins found in various tissues that are induced by exposure to various heavy metals and cellular stress. The function of these proteins appears to be primarily related to metal detoxification and homeostasis (Kagi and Schaffer 1988). Induction by heavy metals and stress may allow this protein to serve as a biochemical marker in organisms exposed chronically to heavy metals such as mercury. Several groups have utilized MTs and other heavy metal binding proteins as a biochemical marker for exposure to heavy metals (Benson et al. 1990; Hogstrand et al. 1991; Gagne and Blaise 1993). Consequently, the purpose of this study was to examine the effects of a chronic laboratory exposure of methylmercury to channel catfish and compare these results to those obtained from field studies where catfish and large-mouth bass had excessive mercury residues.
Pascagoula River Low Flow Management Study
Year: Authors: Branch C.T., Long L.G.
The goals of the study are as follows: (1) evaluate the effect of surface water withdrawals from the Pascagoula River on the balance of fresh water and saltwater in the estuary, and( 2) determine whether any changes in water quality are likely to have a detrimental effect on aquatic habitat in the estuary. In particular, the study focuses on the impact of withdrawals from the river at Cumbest Bluff, at RM 25.4, during low flow periods. It is under these conditions that the estuarine water quality is most likely to be impacted by further reductions in fresh water inflow and possible migration of the salt water wedge upstream. It is important to ascertain whether or not curtailing withdrawals when flows drop below the estahlished minimum is likely to prevent degradation to aquatic habitats. The Jackson County Board of Supervisors is currently permitted to withdraw 100 million gallons per day (MGD) from the Pascagoula River at Cumbest Bluff for industrial uses.
Conversion from Cotton to Short-Rotation Woody Crops: Hydrologic Impacts
Year: Authors: Mitchell B.L., Schoenholtz S.H., Pettry D.E., Joslin J.D., Bock B.R.
The focus of this project is to explore environmental impacts of SRWCs on hydrology by quantifying and comparing hydrologic responses of cottonwood and cotton plantations. This project is designed to determine the usefulness ofSRWCs, as compared to conventional cotton production, for combating soil erosion, improving quality, quantity, and timing of overland flow, intercepting inorganic nitrogen (NO,-N, and NH,N) and phosphate before reaching the groundwater, management of water table depths, and improving infiltration capabilities of soil.
Wellhead Protection in Grenada, Mississippi
Year: Authors: Ingram R.B., Crawford J.L., Goff M.E., Erustun K.H.
The Wellhead Protection Program (WHPP) was established under the 1986 amendments (Section 1428) of the Federal Safe Drinking Water Act (SOWA). This program represents a proactive approach to groundwater protection that is specifically designed to prevent or minimize contamination of groundwater sources used for public water supply (PWS). One of the key elements of the EPA program is the requirement that wellhead protection areas be delineated and protected around PWS wells. These areas are defined as "the surface and subsurface area surrounding a public water supply system, through which contaminants are reasonable likely to move toward and reach each water well or wellhead."
Impact of Climatic Anomalies on Design of Land Application Systems for Disposal of Wastewater
Year: Authors: Wax C.L., Pote J.W., Wasson L.L.
Pote and Wax (1994) developed a computer simulation method to model the operations of land application wastewater disposal systems in the southern region of the U.S. using 30 years of daily weather data. This analysis was later expanded to include five sites across the southern region. Over the time series, one decade was remarkably different from the other two in design results at all five sites. The difference is attributed to the influence of a climate fluctuation like those described above. The purpose of this study is to demonstrate the effect of such an abberation on climatological design criteria and to identify the responsible weather pattern.
Controlled Water-Table Depth to Improve Water Quality
Year: Authors: Willis G.H., Southwick L.M., Fouss J.L., Rogers J.S., Carter C.E.
Management of water table depths may be a means for decreasing amounts of agrochemicals lost from alluvial soils via surface runoff and leaching. For example, if rain appeared imminent soon after pesticide or fertilizer application to the soil surface, the water table could be lowered to enhance infiltration and increase within-soil storage capacity, thereby decreasing runoff loss. Alternatively, if the pesticide and/or fertilizer were already incorporated into the soil surface, the water table could be maintained at some elevation above a subsurface drain line to retard agrochemical leaching below the root zone and thereby retain the chemical in the biologically active root zone longer for utilization or degradation. This paper presents first-year results from a study of the effectiveness of a water management system that uses subdrainage and subirrigation to control water levels for the purpose of reducing agrochemical loss from agricultural land.
A Hydrodynamic Model for the Back Bay of Biloxi
Year: Authors: Passi R.M., Shulman I., Willems R., Lewis J.K.
The Back Bay of Biloxi, located on the Mississippi Gulf Coast, is an estuarine system whose waters of late are coming under increasing stress. Waters in the study area are used for recreational activities and support fish and aquatic life. The environment quality of the region is of major concern, and steps are being designed to protect and balance it against wastewater discharges from industtial and municipal sources located around the Bay. Objective and scientific approaches are being taken to determine Ihe assimilative capacity of the Bay, which will lead to an equitable allocation of wastewater discharge permits so that lhe ecosystem is maintained without inhibiting economic growth. Thc water quality model currently used by Ihe Office of Pollulion Control at the Department of Environmental Quality (Shindala el aI. 1973) is not applicable to the current complex environment and cannot provide satisfactory guidance for issuing permits for wastewater allocation. The University of Southern Mississippi and Mississippi State University are collaborating to develop a Water Quality Model (WQM) which will provide the relationship between waste inputs and their impact on the receiving waters. The WQM consists of two modeling components: (I) a hydrodynamic model (HDM) that predicts the circulation of the Bay based on winds, tides, and freshwater inflow from the tributaries: and (2) a pollutant fate model that uses mass transports across grid cells predicted by the HDM to determine the fate of the pollutants inlroduced into the system. This paper provides preliminary results on the development of Ihe HDM of the Bay.
Agrichemical Transport in Corn on Fragipan Soils in Northern Mississippi
Year: Authors: Cullum R.F., Smith, Jr. S., Schreiber J.D.
Efforts to control soil erosion and associated sedimentation problems in aquatic ecosystems surrounding agricultural lands has lead to increased adoption of no-till (NT) and other reduced-lill (RT) practices in this region. However. NT and RT practices often require an increased use of herbicides to control weeds that are usually controlled by conventional tillage (CT). Also, increased infiltration generally associated with conservation tillage needs evaluation to determine the potential increase of contamination of our Nation’s ground water with agrichemicals. The main objective of this study was to evaluate agrichemical transport and losses in runoff and shallow ground water from corn grown under different tillage practices in northern Mississippi to assist in development of better conservation tillage systems and agrichemical application practices.
Wind Effects on Gas Transfer at Air-Water Interface
Year: Authors: Zhou D., Wang S.S.
Gas transfer plays an important role in many environmental phenomena such as the reaeration of polluted streams, the fate of volatile toxic pollutants, the water contamination caused by atmospheric pollutants transferred through the air-water interface, etc. Because of its impact on environmental pollution, water quality, and climate changes, it has recently become an important subject. Natural water bodies (streams, Lakes, ponds, reservoirs. seas) are exposed to wind. The presence of wind makes the gas transfer process a complicated phenomenon. The air and water flows above and below the air-water interface are dynamically coupled. Also, the interface is a moving boundary which is governed by the coupled dynamics. There is considerable exchange of momentum and energy at the interface. If the water is initially at rest, then due to the wind action, surface waves will be generated (Miles 1957: Phillips 1957), and in the meanwhile, a surface drift will also be present (Wu 1975). The initiation of the motion of the water body will in two significantly affect the air now. The interface dynamics is itself a subject currently under study. The related gas transfer process is even more complicated. Simply speaking. the now conditions of the water surface layers, the wind conditions. and the bubble dynamics play roles in the gas transfer process (Kanwisher 1963). Because of the complexity of the problem, needless to say, certain simplifications are needed. Experimental and field studies have been conducted to investigate how the transfer coefficient is affected by the wind action. For example, through their experimental study. Merlivat and Memery (1983) found the linear correlation between the gas transfer coefficient and the representative wind wave speed. Jahne et aI. (1985) concluded from their large wind wave facility experiments that the wave characteristics must be included as parameters to describe the gas transfer process. To add to the complexity of the problem, Jahne et aI. (1987) further revealed from their wind wave tunnel experiments the change of the gas transfer coefficient dependency on the Schmidt number (Sc=\nu/D). On the modeling aspect, the interface has been traditionally regarded as a fixed smooth boundary. Only recently effort has been made to include the effect of wave motion. For instance, Coantic (1986) considered the capillary wave effect in his model and evaluated the resulting transfer coefficients under different assumptions of the hydrodynamic conditions. Using oxygen as the transferred gas, Daniil and Gulliver (1991) conducted experimental studies to investigate the breaking wave effects on the gas transfer coefficients. By assuming that the enhanced gas flux at higher wind speeds results from bubble entrainment in small scale breaking waves. Kerman (1984) tried to correlate the enhanced gas transfer to the group wave characteristics. The effect of the surface drift, however, is still not included. The present investigation will include the surface drift and wave affects on the gas transfer process in the simple mathematical model.
Environmental Risk Assessment
Year: Authors: Yuan P.C.
During the last decade, there has been much public attention and concern about the effects of chemicals, radiation, science, and engineering in general impact on health and living environment. Several scenarios such as the pollutant release at a chemical dump site in Love Canal, New York: Methyl isocyanide exposure in Bhopal. India: Dioxin levels high in Leaf River, Mississippi; and hospital needles found on the beach in Biloxi, Mississippi raise questions about the possibility that similar problems may occur. These include not only sites near the hazardous waste disposal sites and chemical plants, but also from transportation of hazardous chemical and nuclear wastes. "Zero-risk" situations are never attainable and are probably not desirable.
Bridge Scour in Mississippi
Year: Authors: Wilson, Jr. K.V.
This paper briefly summarizes pier-scour data collected during 1942-94 at 22 selected bridge sites in Mississippi (Figure I). These data and additional bridge-scour data collected during 1938-94 are described in more detail by Wilson (1995). The methods used to measure scour and selected characteristics at each site are described. Selected hydraulic and bridge-geometry characteristics are presented. An envelope-curve equation for the Mississippi pier-scour data was developed by relating measured pier-scour depth divided by normal pier width to measured approach-flow depth divided by normal pier width. The measured pier-scour depths were compared to the envelope curve and to the pier-scour prediction equation recommended in the Federal Highway Administration (FHWA) Hydraulic Engineering Circular No. 18 (HEC-18) by Richardson and others (1993).
Use of Geographic Information System and a Computer Simulation Model to Estimate Vadose Zone Loading of Pesticides
Year: Authors: Johnson A.B., Scott H.D.
There is much unknown about the extent of pesticide contamination of groundwater in Arkansas. Several research projects. in recent years, have been conducted where wells used for domestic and irrigation water uses have been sampled and analyzed for pesticides (Lavy et al. 1988; Nichols et al. 1993). For state and federal regulatory agencies, evaluation of the potential groundwater contamination begins with considering those areas in the state where pesticides are used. With relatively large cropland and only limited financial resources available for chemical analyses, the question of where these agencies should begin to sample the groundwater for pesticides is pertinent. Therefore, there is a need to develop a scheme that can be used to optimize the available. but scarce. resources. It was the objective of this study to estimate areas in Woodruff County, Arkansas, where the groundwater was highly vulnerable to pesticide contamination and to simulate the transport of mobile pesticides in those areas.
Zooplankton Distribution in Riverine Macrohabitats of the Tennessee-Tombigbee Waterway
Year: Authors: Jackson D.C., Sarnita A.S.
Zooplankters are initial prey for most fish species (Siefert 1972; O’Brien et al. 1984: Keast and Eadie 1985; Noble 1986). The availability (distribution and abundance) of zooplankton within a system can determine fish stockspecific early life history habitat utilization, growth, and ultimately recruitment processes either directly or indirectly through zooplanktivory by intermediate prey organisms. Our objective was to determine distribution and abundance of zooplankton among the three riverine macrohabitats. Two null hypotheses were formulated: 1. There is no significant difference among riverine macrohabitats with respect to cumulative zooplankton (rotifers, cladocera, and copepods combined) densities (number/m’). 2. There is no significant difference among riverine macrohabitats with respect to cumulative zooplankton (rotifer, cladocera, and copepods combined) biomass (~g/m’). Significance was established at P <_ 0.05.
Microbial Transformation of P-Cresol, 2,4,5-Trichloroaniline and its Photoproducts in Aquatic Environments
Year: Authors: Hwang H.M.
One of the useful approaches to measuring microbial degradation rates of chemical pollutants is to determine the kinetics of heterotrophic potential for the utilization of the chemicals. One of the basic assumptions for measurement of heterotrophic potential is thaI all members of microbial consortia respond in the same way to variations in substrate concentration. This assumption may not be true because evidence exists for differential uptake rates by various bacterial populations and by algal versus bacterial populations (Atlas and Bartha 1993). In this study. separation of microorganisms of different classes were achieved by size-fractionation with polycarbonate membrane filter. The contribution of microorganisms of different sizes to transformation of p-cresol and trichloroaniline photoproducts were determined.
Sociological Factors Influencing Farmers’ Adoption of Best Management Plans for Enhancing Water Quality in the Mississippi Delta Management Syst
Year: Authors: Gill D.A.
Some of these practices are currently being used by some farm operators in the Delta. Others are seem economically unsound or have not been perfected for use in the Della, One of the primary goals of the MESA research project is to evaluate various practices in terms of impacts on oxbow lakes and determine which is the best practice for managing water quality. An imponant component of BMP identification is underslanding current management practices and developing a cropping history. More importantly, the economic costs of a BMP must be considered. For these reasons, it is essential that farm operators be involved at all stages of the research.
Operation of Water Table Control System for Water Quality Improvement
Year: Authors: Fouss J.L., Rogers J.S., Willis G.H., Southwick L.M., Carter C.E.
Integrated management of soil and water resources and agronomic cultural practices is necessary to insure environmentally sound crop production on shallow water table soils in humid areas (such as the LMV), and to reduce or eliminate potential pollution of water resources, including adjacent wetland areas. Integrated methodology is urgently needed to manage soil, water, ground cover, fertilizer and pesticide applications in such a way that fertilizers and pesticides are contained in their functional "action zones" of the soil profile. It should be possible to manage water table depth to control root-zone soil-water content such that plant fertilizer use efficiency is enhanced, thereby decreasing fertilizer needs and reducing nument pollution potential. Furthermore, recent research has shown that improved soil-water management increased earlyseason crop growth and provided canopy cover that decreased weed populations (Carter 1990). This decrease could reduce herbicide needs and thereby lower pollution potential. There is also an opportunity to reduce pollution by overall pesticide management practices, particularly for those pesticides that degrade as a function of soil moisture and aeration conditions. The reduced need for fertilizers and pesticides would thus increase profits to farmers.
Green-Ampt Infiltration in Layered Soils with Positive Soil Water Potential
Year: Authors: Deliman P.N., McFarland M.J.
The overall objective of this study was to develop a method that will provide an accurate estimate of cumulative inflitration during the occurrence of positive soil water potentials in layered soils. Part of that objective involved modeling the movement of the wetting front through the layered soil. An existing wetting front model, the Green-Ampt model, was modified to allow for the occurrence of positive soil water potentials. Using the modified Green-Ampt model, a wetting front model was developed to accomplish the overall objective.
Blue River Drop Structure: Impact on Historical Site Blue River, Kansas City, Missouri
Year: Authors: Cooper D.
The design for channel improvement of the Blue River was in accordance with sound engineering procedures: however, the need for a model study was considered essential due to significant energy dissipation problems expected downstream of the grade control structure. The model study was necessary to insure the integrity of the channel design while attempting to minimize Ihe real estate requirements by the city of Kansas Cily. The physical model was also needed to verify the hydraulics of the proposed stilling basin design. With multiple weir elevations, now conditions across the basin are not uniform.
The Tertiary-Quaterary Aquifer Relation in Northwestern Mississippi
Year: Authors: Bryant C.
Ongoing studies by OLWR have shown that direct recharge to the alluvial aquifer from some of the interior streams within the Yazoo Basin, rainfall on the surface of the alluvium, and even from the Mississippi River in certain areas is not as significant as previously thought. As pumping for irrigation and fish culture continues to increase in the Delta, it is imperative that we understand this ground-water flow system and the influences upon it if we are to prudently manage this water resource. One of the least known influences upon the alluvial aquifer is its relationship to underlying Tertiary aquifers. The two main goals of this project were to: 1) determine if the alluvium is connected with an underlying aquifer at several sites; and 2} conduct aquifer tests by which several aquifer properties can be characterized at these sites.
Contaminant Levels in Fish and Shellfish from the Emap Estuaries Louisianian Province
Year: Authors: Benson W.H., O'Neal J.M., Allgood J.C., Summers J.K.
Currently, one-sixth of the U.S. population lives in Slates bordering the Gulf of Mexico. Many of these citizens either directly or indirectly depend on the Gulf of Mexico for their livelihood (DOC 1990a; 1990b). Two-thirds of the contiguous U.S. drains into the Gulf of Mexico (Buff and Turner 1997). Ports along the Gulf handle 45% of U.S. import-export shipping tonnage. Approximately one-third of the marine recreational fishing activities in the continental U.S. occur in the Gulf. Forty percent of the U.S. commercial fish and shellfish yield, approximately 2.5 billion pounds each year, comes from the Gulf. The Gulf provides critical habitat for 75% of the nation’s migrating waterfowl, some 500 species, and is home to numerous endangered species (EPA 1992). Nevertheless, to date, relatively little attention has been focused on environmental The purpose of this investigation was to address these items of concern by conducting analytical chemistry evaluations which encompassed species (fish and shellfish) collected from the Gulf of Mexico. Specifically, this study represents the second year of data available for analytical chemistry evaluations from the EMAP - Estuaries Project for 1993.
Distributed Data Acquisition for Monitoring Stormwater Runoff
Year: Authors: Burcham T., Wren D., Varco J.
In July 1993, the Appalachian Regional Commission funded a research project to help identify proper methods to land apply swine wastewater in an environmentally sound manner. The research has three major objectives: (1) determination of soil storage and forage utilization of applied wastewater nutrients; (2) to determine offsite nutrient movement by measuring and sampling surface runoff; and (3) to determine associated economics from data obtained in objectives one and two. Identifying soil storage and forage uptake of wastewater applied nutrients (objective 1) is well underway. One full year of data has been collected. Adeli et al. (1995) resported on first year results from the nutrient utilization component of the project. Initial results indicate that nutrient uptake by the forage is similar for plots receiving commercial fertilizers and swine wastewater. A relationship between quantity of wastewater applied and phosphorus accumulation in the upper 5-cm of the soil profile was found. Measurement and sampling of surface runoff (objective 2) is difficult due to the complexity and cost of required equipment. In order to facilitate replication in the offsite nutrient movement component of this research, innovative technologies have been sought and are being implemented to measure and sample surface runoff from eight research plots (four treatments with two replications). Presented here are apparatus and methods to achieve cost effective flow-weighted sampling on multiple runoff plots.
Biology of Paddlefish in a Mississippi Delta River
Year: Authors: George S.B., Hoover J.J., Killgore K.J., Lancaster W.E.
During recent fish surveys of the Big Sunflower River (Hoover and Killgore 1994), we (SGG, JJH, KJK) observed paddlefish at several locations, capturing only a few specimens. A fisherman (WEL) reported paddlefish in moderate numbers as by-catch from commercial fishing for buffalo suckers (Ictiobus spp.); these specimens were frequently dead or moribund, depending on time of year and length of time in net. Collaboration allowed us to conduct life history study with no extraneous pressures on the fish population (i.e., by retaining and processing nonviable fish), resulting in the first known field study of paddlefish in the Yazoo River Basin of the Mississippi delta. This paper presents work-in progress and describes; I) relative abundance in three reaches of the Big Sunflower river; 2) associations between river stage and catch; 3) length-weight relationships; 4) food habits; 5) demography; 6) cranial morphology.
Water Quality Values of Winter-Flooded Rice Fields: An Experimental Evaluation
Year: Authors: Manley S., Schoenholtz S., Rodrigue P., Kaminski R.
There is a need to implement current methods and discover new means of reducing NPS pollution with a focus on techniques that maintain sediments and nutrients at their source (USEPA 1990; Baker 1993; USEPA 1994a. 1994b). Federal and State agencies are now taking a partnership approach to meet such needs (e.g.. Management Systems Evaluation Areas). There is a growing consensus that NPS pollution control issues can best be solved at the basin or watershed level (USEPA 1994a. 1994b). Integrated approaches with multiple ecological and agricultural benefits would be most effective in solving today’s NPS pollution and water quality challenges. In response to these challenges, we propose to address NPS pollution and water quality problems relative to contemporary agricultural and wildlife conservation practices in the Mississippi Delta. Specifically, we propose to investigate NPS pollution abatement and water quality values of winter-flooded rice fields. Wildlife conservationists promote provision of shallow (<15 cm) wetlands on agricultural areas, particularly those farmed for rice and soybean production, to provide quality foraging and resting habitat for migrating and wintering waterbirds (Reinecke et al. 1989). Flooding harvested rice fields is panicularly beneficial because rice seeds resist decomposition (Neely 1956; Shearer et al. 1969) and are nutritionally better for waterfowl than other crop seeds (Joyner el al. 1987; Loesch and Kaminski 1989). Additionally, rice is grown in an aquatic environment with water-management systems facilitating impoundment.
Pesticide Transport Research at the NSL: Past, Present, Future
Year: Authors: Smith, Jr. S., Cooper C.M., Knight S.S., Willis G.H., Southwick L.M.
The National Sedimentation Laboratory (NSL) opened in 1959 as a result of Senate Document #59 (86th Congress). The Laboratory was charged with being a national center for sedimentation research and with solving problems related to sediment transport and deposition in stream channels and reservoirs. Additions to the NSL occurred in 1969 and 1987 resulting in total building space of about 55.000 square feel. From the beginning, NSL researchers have been engaged in measuring stream flow and sediment transport in large watersheds. Research in the 117-square mile Pigeon Roost Creek Watershed (1957-1979) near Holly Springs, Mississippi, provided comprehensive sediment transport data used in the development and evaluation of sediment transport equations. Since 1982. NSL scientists have collected runoff and sediment discharge data from the 8-square mile Goodwin Creek Watershed located about 15 miles west of the Laboratory. This research watershed is part of the Demonstration Erosion Control (DEC) Project in the Yazoo Basin and is cooperative with the U.S. Army Corps of Engineers and the Natural Resources Conservation Service (formerly the Soil Conservation Service). Data from the Watershed are used to develop hydrologic model parameters and for model validation. DEC in-stream stabilization practices, ecological features, and other related measures are also being evaluated. For twenty years (1965-1985) the NSL was involved in sedimentation research in more than 1200 reservoirs throughout the United States. As early as 1968, NSL researchers were involved in agrichemical transport by sediments, fate in reservoirs, and impact on watershed ecosystems. This work continued through the 1970s and involved pioneering studies of sediment and agrichemical transport from Mississippi Delta flatland soils. Field and laboratory studies of upland infiltration and erosion began in the mid-1970s and the results have contributed significantly to the Water Erosion Prediction Project (WEPP) and to the Revised Universal Soil Loss Equation (RUSLE). The NSL is a partner with the University of Mississippi’s Center for Computational Hydroscience and Engineering in developing computational methods related to hydrology. erosion, and sedimentation and the National Center for Physical Acoustics in conducting research and developing instrumentation for studying soil porosity, streambed elevations, and sediment movement via acoustical methods. Research at the NSL is currently divided among three organizational units: Upland Erosion Processes, Water Quality and Ecological Processes, and Channel and Watershed Processes. Scientific disciplines include: hydraulic engineering, agricultural engineering, agronomy, soil science, soil physics, geology, hydrology, ecology, biology, and chemistry,
Using the Radial Basis Function to Predict the Quality of Mississippi Gulf Coast Oyster Reefs
Year: Authors: King R., Powell W.C., Sherrard J.
The Mississippi Gulf Coast oyster reefs are divided into eight areas. Each area is classified as approved. conditionally approved, restricted, or conditionally restricted based on a sanitary survey as designated by the National Shellfish Sanitation Program (NSSP) Manual of Operations developed by the U.S. Food and Drug Administration (FDA). Areas are monitored at their respective sampling stations for fecal contamination on a continual basis. These stations are used to classify zones within each area. A zone is closed down when its respective sampling station indicates through lab testing that fecal material, pathogenic microorganisms, and/or poisonous and deleterious substances are present within the zone, and the zone cannot be classified as approved. The determination that the approved classification standards are met is based upon a minimum of 15 samples collected from the zone’s respective station. The zone is classified as approved when the fecal coliform median or geometric mean Most Probable Number (MPN) of the water does not exceed 14 per 100 ml and not more than 10 percent of the samples exceed an MPN of 43 per 100 ml (Food and Drug Administration 1992).
Formation Hydrofracturing in the Paleozoic Aquifer Corinth Municipal Water Well Project Corinth, Mississippi
Year: Authors: Tarver R.R., Swann C.T., Lockhart D.L.
The occurrence of groundwater in extreme northeastern Mississippi is very different from that of the rest of the state. It is derived from hard sedimentary rocks, occurring near the surface in the region, which are known to produce high quality water. Water well engineering design and groundwaler production techniques for these hardrock aquifers differ from sandy unconsolidated aquifers, which are more typical to the remainder of the state. Over the last decade, the Mississippi Mineral Resources Institute (MMRI) has had a continuing interest in the groundwater production in northeast Mississippi with primary focus on the Corinth district. where MMRI has assisled the Corinth Gas and Water Depanment (CGWD) in locating water production wells. The source of the public water supply in Corinth is the Paleozoic aquifer. Groundwater from this aquifer is more desirable than that from the shallower Cretaceous aquifer because of its lower iron and manganese content. Although deeper wells are required, it is more economical to produce groundwater from the Paleozoic aquifer than to remove these unwanted materials from water produced from the Cretaceous formations.
Initial Assessment of Forestry Streamside Management Zones in Loess Bluffs
Year: Authors: Keim R.F., Schoenholtz S.H.
The non-point source pollution potential of forest harvesting and management activities (EPA 1980) has prompted many states to adopt voluntary or mandatory Best Management Practices (BMPs) programs to reduce such effects and protect stream water quality. One important component of BMPs is the Streamside Management Zone (SMZ) - a reduced-impact area adjacent to a stream designed to provide a buffer from watershed disturbance activities. As a component of BMPs, SMZs are expected to ameliorate increases of sediment and nutrient inflows to streams, as well as to modify stream temperature changes (Lowrance et aI. 1985). The filtering ability of SMZs is due to the roughness of the intact forest floor that slows water flowing overland (Cooper et aI. 1987). This loss of velocity decreases the water’s sediment-moving capacity (Warrington et aI. 1980; MacDonald et aI. 1991). Negatively affecting SMZ effectiveness is slope steepness (Mississippi Forestry Commission 1989). However. there has been limited research done on SMZ effectiveness applicable to the coastal-plain South, particularly the loess bluff region of Mississippi. One objective of this ongoing research is to study the effectiveness of SMZs on small. first-order intermittent streams in watersheds that have highly erodible loess soils and slopes as steep as 100%.
Streamflow Characteristics of the Lower Pascagoula River, Mississippi
Year: Authors: Turnipseed D.P., Storm J.B.
This report describes and presents streamflow data collected by the USGS in 1993-94 for the lower Pascagoula River. These data are correlated with data collected using conventional streamgaging methods, an ADCP to measure three-dimensional velocity profiles, and a continuous-recording acoustic velocity meter (AVM). Examples of continuous stage, velocity, and discharge relations computed for data obtained from the USGS continuous recording stage and acoustic velocity streamgage at the Pascagoula River at Graham Ferry are presented.
State Space Time Series Modeling the Effect of Feeding Rate on Dissolved Oxygen and Successive Feed Consumption in Channel Catfish Culture Ponds
Year: Authors: Taylor J.B., Shanmugam R., Unprasert P.
Tackett et aI. (1988) reported high daily vanatton in amount of feed consumed among channel catfish in ponds fed using demand feeders. They observed increased variation at the highest study density: daily differences averaged as high as 61% for 259-g flsh stocked at 3468/ha. This suggests daily variation in feed consumption may be quite high at commercial culture densities. Anecdotal repons from personnel at the South Farm Aquaculture Research Unit of Mississippi State University suggests feeding activity may be negatively related to feeding activity of the previous day. Information is lacking on the short-term interrelationships between variation in feeding rate and dissolved oxygen fluctuations in culture ponds.
Overview of the Hydrogeology and Analysis of Ground Water Withdrawal in the Mendenhall-D’Lo Area, Simpson County, Mississippi
Year: Authors: Strom E.W., Oakley W.T.
The cities of Mendenhall and O’Lo, located in Simpson County, Mississippi, rely on ground water for their public supply and industrial needs. Most of the water comes from an aquifer of Miocene age. Regionally, water levels in Simpson County have been declining at the rate of about I foot per year (Newcome et aI. 1972). Continued population growth and the development of new industries may increase the rate of water-level decline. In 1991, the U.S. Geological Survey, in cooperation with the Pearl River Basin Development District and the Mississippi Department of Environmental Quality, Office of Land and Water Resources, began an investigation for the purpose of describing the hydrogeology, analyzing effects of ground water withdrawal by making a drawdown map, and projecting the possible effects of increased ground water withdrawals on water levels in the Miocene aquifer within the Mendenhall-O’Lo area (Strom and Oakley 1995). This paper describes the hydrogeology of the area and presents the results of the analysis of the effects of ground water withdrawals through 1994 on water levels.
Impact of Vegetative Grass Filter Strips on Herbicide Loss in Runoff
Year: Authors: Shaw D.R., Webster E.P.
In order to accomplish the goal of optimal weed control in a soil conservation program, increased reliance on chemical means of weed control is necessary (Shaw and Rainero 1990). There is a large amount of information on the effectiveness of vegetative filter strips on reducing nutrients and suspended solids from runoff, but little research has been reported on herbicide loss. The objective of this research was to evaluate the effectiveness of vegetative filter strips on reducing the loss of metolachlor and metribuzin in runoff from three soybean production systems. This research was conducted for 3 years to assess the impact of variable environments in losses from the three systems with and without a filter strip.
Dredge Disposal Technique Improves Agricultural Lands
Year: Authors: Sanders J.
Thin layer disposal is the process by which hydraulic dredged material (usually from fresh water rivers) is deposited in a Confined Disposal Facility (CDF) in relatively thin layers. When the drying process is complete, the consolidated material is about 4 to 5 feet in thickness. Placing this material on cleared agricultural land allows the land to continue functioning for agricultural purposes. Why is this so important? Historically, disposal placed on agricullural lands through the hydraulic dredge process has rendered the lands useless. There is a saying among Delta farmers that "they ain’t making no more cotton land." This saying was true until thin layer disposal became a reality. This process not only improves the quality of the land, but elevates the land out of the frequently flooded zone. To understand the need for thin layer disposal. an understanding of the development of the Yazoo Basin and the importance the land plays in the economic stability of the region is important. Preservation and protection of the land through environmentally sensitive flood control projects are necessary.
Phototoxicity of Fatty Acids Present in Dairy and Hog Manure
Year: Authors: Rizvi M., Edney N.A.
Application of animal waste on farm land is currently considered as a safe method to dispose the excreta of farm animals because it provides an easy outlet to alleviate environmental dangers associated with farm animal excrela. It is generally believed by agricultural professionals that cattle, hog, and chicken waste is a valuable resource of plant nutrients. Thus land application of waste converts waste into a valuable resource by reducing the cost of fertilizers. This belief is based on concrete data collected in widely varying locations showing that farm animal excreta has the same macrocomponents, nitrogen, phosphorus, and potassium (NPK) as a traditional commercial fertilizer. The Proceedings of the International Symposium on Agricultural Food Processing Waste (ASAE 1990) may be referred to for most recent reviews on the subject. In most studies published during the last thirty years, farm animal waste is viewed as a good source of NPK (McCaskey et al. 1990). Little attention has been given to the minor chemical components present in the contents of excreta. The significance of minor chemical components of animal waste has been overshadowed by the desired results of the land application of farm animal waste. Information about minor chemical components present in the contents of farm animal excreta is not well documented (Marambe and Ando 1992).
Deterministic Assessment of Agricultural Nonpoint Source Pollution in Mississippi Delta Management Systems Evaluation Areas (MSEAs)
Year: Authors: Rebich R.A., Schreiber J.D., Pote J.W.
Although BMPs have been recognized as alternatives for reducing the transport of chemicals and sediment from agricultural fields, the overall effects of BMPs, both individually and collectively, and their effectiveness from one agricultural region to another have yet to be fully assessed. Research activities designed to identify the benefits of BMPs on operational farms or at the farm level are difficult and expensive. Thus, most of the research and monitoring activities used to design and evaluate the performance of BMPs are conducted on small watersheds and experimental plot studies. For example, research by Webster (1993) on experimental plots showed that grassed filter strips aided tillage practices in reducing pesticide transport in runoff from soybean fields. However, some BMPs that work well for one agricultural region may not for another. For example, reduced tillage practices intended to decrease sediment and agrichemical transport in surface-water runoff may increase chemical transport into shallow ground water depending on soil type and other factors. Also, a panicular BMP or set of BMPs that may reduce all forms of agricultural nonpoint source pollution very effectively may be too expensive for a producer to implement in a farming system. Deterministic research that includes socio-econornic, as well as environmental. evaluations of BMPs at the farm level is necessary before regulatory policies are implemented.
The Creation and Use of Spatial Data Layers to Evaluate the Susceptibility of Ground Water in Mississippi to Contamination from Surface and Shallow So
Year: Authors: O'Hara C.G.
Ground water, because of its extensive use in agricultural, Industrial, and general applications, is one of Mississippi’s most important natural resources. The Mississippi Department of Environmental Quality, Office of Pollution Control, and the Mississippi Department of Agriculture and Commerce, Bureau of Plant Industry, are developing programs to protect ground water in Mississippi from contamination from surface and shallow sources. The U.S. Geological Survey (USGS), in cooperation with these two agencies, is conducting an evaluation of the susceptibility of ground water to contamination from surface and shallow sources in the outcrop areas of the major aquifers in Mississippi. The studies are conducted through the use of a geographic information system (GIS) that contains statewide spatial data layers describing geologic, hydrologic, physiographic, and cultural factors. The results of the study will provide needed information to planners and managers as they design and implement groundwater protection and management programs.
Application of Revised Universal Soil Loss Equation (RUSLE) to Mississippi
Year: Authors: McGregor K.C., Foster G.R., Mutchler C.K., Golden J.L.
The USLE recently was revised and released as the Revised Universal Soil Loss Equation (RUSLE) by the USDA-Agricultural Research Service (ARS), NRCS, and cooperators through the Soil and Water Conservation Society (Renard et al. 1995a). RUSLE is a significant advancement and improvement over the USLE. This paper describes some of these improvements and gives some example applications for Mississippi.
Genetic Manipulation of a Cyanobacterium for Heavy Metal Detoxification
Year: Authors: McCormick P., Cannon G., Heinhorst S.
In Saccharomyces cerevisiae, copper resistance is mediated by the cup I gene which encodes the yeast copper metallothionein. The 53 amino acid polypeptide (the first 8 amino acids encoded in the gene are removed by posttranslational modification of the mature protein) contains 12 cysteine residues capable of binding 8 copper ions. While inducible in the organism only by copper and silver ions, studies indicate in vitro ability of the protein to coordinate cadmium and zinc ions as well (Winge et al. 1985). A study by Fogel and Welch at the University of California at Berkeley showed that markedly enhanced copper resistance in yeast was a result of tandem gene amplification (Fogel and Welch 1982). Research has shown (Karin et al. 1984) that the copper chelatin gene alone (when present in sufficiently high copy number) seems to be sufficient for development of copper resistance in yeast. Given the structural similarity of the yeast and the cyanobacterial (Olafson et al. 1988) metalloprotein molecules (both are class II metallothioneins), the goal of this work will be to express the yeast copper metallothionein protein in a cyanobacterium. For this purpose, cloned sequences of the yeast cup I gene, both in single and multicopy constructs, have been obtained.
A Review on Ecological Status of Global Wetlands with a Special Emphasis on Water Quality and Fresh Water Macrophytes
Year: Authors: Kambhampati M.S., Leszczynska D.
Ecologically, wetlands are complex systems and represent extremely important natural resources. The goal of this paper is to compare the status of wetlands by physical and chemical parameters in two different geographic locations. Being low lying areas, most of them serve as sinks for receiving nutrients and sediments from the drainage basin and are often looked upon as wastelands. However, several wetlands are utilized as a direct resource for plant materials like reed etc., for fish or used for the cullivation of edible plants like Trapa and/or deep water rice. In some pockets of the north-eastern region of India, the wetlands are believed to play an important role in the maintenance and survival of the local people. The importance of detritus derived from marshes in the aquatic food chains is well known and needs no over emphasis.
In-Situ Biological Methods for Cleanup of Creosote and Pentachlorophenol in Groundwater
Year: Authors: Borazjani A., Diehl S.V., Strobel D.A., Wasson L.
The objective of this research is to investigate the development of a rapid in-situ biological technique for the cleanup of organic wood preservatives in groundwater at a wood treating site in southern Mississippi. This involves the use of naturally occurring microorganisms as well as bacteria species previously isolated at our laboratory capable of degrading PCP and PAHs at a rapid rate. Since the bioremediation process is an aerobic process, the use of added oxygen and micronutrients will also be investigated as possible methods to enhance the bioremediation process. Analytical techniques applied to water samples obtained from wells already in place will be used to monitor the treatment effectiveness.
Potential for Application of Ultrasound in the Wastewater Treatment Process
Year: Authors: Balasubramaniam K., Abesingha C., Kumar S.B.
The physical mechanisms of ultrasonic interaction with materials are: (I) physical, (2) chemical, and (3) thermal, The basic physical mechanism related wave propagation including standing wave patterns, bubble oscillation causing cavitation and Bernoulli’s forces, and bulk effects such as decrease in effective viscosity, micro-streaming, and interparticle shearing. The domination of one or more of these effects will depend upon the frequency-target size ratio as well as the geometrical and intensity characteristics of the ultrasound generation, In this section, the several technical issues associated with the ultrasonic phenomena and various physical principles used in the proposed research will be briefly discussed.
Water Resources Information Clearinghouse Scientific and Engineering Information Standards for Mississippi Department of Environmental Quality Office
Year: Authors: Al-Turk E., Erustun K.H.
This project represents a continuation of the previous efforts toward addressing the data management issues at DEQ as part of the State Water Management Plan Outline development and will be a building block of the development of a comprehensive water resources information management system which is a component of the Department’s overall plan for the development of DEQ Scientific Information Management System (SIMS). The objectives of this project are as follows: Phase I 1. Review and inventory all scientific databases at DEQ. 2. Inventory water resources databases that DEQ access remotely from sources such as EPA, USGS, and FEMA. 3. Classification of DEQ scientific databases into the environmental clearinghouses identified in the conceptual Scientific Data Management Program Interim Report dated March 1993. 4. Review and adopt water resources data collection standards which include groundwater flow data, groundwater chemical and physical quality data, surface water (open channel flow) data collection, and surface water and sediment sampling standards. 5. Review and inventory water resources data element standards for groundwater quality, groundwater quantity, surface water quality, and surface water quantity clearinghouses. 6. Deveopment of Geographic Information System (GIS) standards to organize water resources spatial data requirements in an integrated fashion. The GIS standards will focus on mapping consideration, data structure, data creation procedures, and data quality and quantity verification standards. 7. Collection of field data utilizing GPS equipment to determine horizontal and vertical locations of representative water resource facilities within jackson County, Mississippi, for use in the development of the standards verification program, Phase II. In addition to field data collection, obtain 1":24,000" base mapping for the demonstration project area. Phase II 1. Develop a demonstration project for a small geographic area to illustrate how the standards developed in Phase I can be utilized as a gool for better management of the State of Mississippi Water Resources and the integration of surface and groundwater information. 2. Identify any discrepancies in the standards developed in Phase I. 3. Identify root causes of standards discrepancies.
Swine Lagoon Effluent and N-P-K Fertilizer Effects on Yield, Nutrient Removal, and Residue Soil Levels of N and P
Year: Authors: Adeli A., Varco J.J., Burcham T.
Since nutrient content in lagoon effluent, especially N and P, are of prime importance for both supplying crop nutrient requirements and as a potential source of pollution. This investigation is concerned with the proper management of the swine lagoon effluent. Also, societal concerns about ground and surface water pollution have increased in recent years and have caused livestock producers to reevaluate waste management strategies. Thus, proper and efficient management of swine lagoon effluent on cropland may improve crop production economics but must not result in degradation of water quality. Given this background, the objective of this study was to evaluate the agronomic and environmental aspects of various rates of swine lagoon effluent on forage yield, nutrient uptake. and residual soil levels of N and P relative to inorganic fertilizer.
Evaluation of a Constructed Wetland’s Effects of Remediation of Water Quality in a Recirculating Catfish Aquaculture Pond
Year: Authors: Anderson G., Anderson D., Biesiot P., Wang S.
The overall objective of our study was to evaluate the performance of a constructed wetland as a water treatment biofilter for a recirculating catfish aquaculture pond. Two systems were evaluated during our work. The fIrst is a system which was built in 1989; the plants in the constructed wetland were already established when we began our monitoring program in 1990. The second system was built in 1990, but the constructed wetland was not completed until 1991 and the macrophytes did not become well established in the wetland until recently. In this paper, we report on only the first system.
The Effects on Low Flows on the Flathead Catfish (Pylodictis Olivaris) in the Upper Sunflower River
Year: Authors: Yarborough G.M., Pennington D.A., Lucas G.
The Sunflower River is a low gradient, warm water river which runs through the Mississippi Delta. It is important to several nearby municipalities as a source for effluent dilution and is utilized for crop irrigation and both recreational and commercial fishing. Base flows in Delta streams are produced from water entering the stream channel from the Mississippi River Alluvial Aquifer. Over the past years, the decline of the Mississippi River Alluvial Aquifer level, due to heavy agricultural use, has been followed by the decline of base flows in the Sunflower River. The multiple uses of this river make the decrease in these flows a significant issue.
High Selenium Concentration and Selenite-Hyperresistant Bacteria in the Lower Stream of Mississippi River
Year: Authors: Yang W.H., Baaree A., Yang J.R., Yee A.
This study utilizes the ICP-AES for multi-element analysis of surface water from the Mississippi River. This investigation was carried out as a follow up to the earlier report (Yang et al. 1993) which showed the presence of selenite hyperresislant bacteria in the soil along the Mississippi River, an early indication of early sign of selenium pollution in the river.
The Timing and Quantities of Effluent Discharged from Commercial Catfish Farms in Mississippi
Year: Authors: Waldrop J.E.
The discharge of effluent from any commercial activity should be in a form that has little, if any, undesirable impacts on the environment. Because commercial catfish farms discharge excess water from production ponds, they are not exempted from this requirement. In order to assess the environmental impact of water discharged from commercial catfish farms, data on the amount discharged, the time of year of discharge, contents of the discharged water, and the state of the receiving stream at the time of discharge must be collected and summarized for food fish and fingerling producing units. This report details the discharge of water from commercial food fish and for fingerling production ponds and the typical timing of the effluent discharges.
Crop Water Use in the Mississippi Delta
Year: Authors: Thomas J.G.
Irrigation has grown tremendously in the past century. Technology has certainly increased its useability and efficiency, yet management is still the key to making it a profitable tool. With the technical advances made, producers still face some of the same decisions and problems that faced the early irrigated producers of this century. Market prices, adverse weather, insects and many other problems that face agriculture during a production year are still the same or very similar to those of almost 100 years ago. Technology has brought production agriculture a long way, yet sometimes it seems as though it hasn’t advanced much at all.
System Characteristics and Removal Efficiencies of a Constructed Wetland Designed for Tertiary Treatment of Bleach-Kraft Pulp Mill Effluent
Year: Authors: Tettleton R.P., Howell F.G., Phillips P.A.
The purpose of this Study is to measure changes in target parameters while maintaining a constant depth in each experimental wetland cells, altering only flow rate, to arrive at site specific design criteria that can be used in the development of a larger constructed wetlands for treatment of all or part of = 20 million gallons of wastewater discharge per day.
Framework for Flow Analysis of the Eutaw-McShan and Tuscaloosa Aquifers in Northeastern Mississippi and Adjoining Parts of Arkansas, Tennessee, and Al
Year: Authors: Strom E.W.
The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, Office of Land and Water Resources (OLWR), began an investigation of the Eutaw-McShan and Tuscaloosa aquifers in northeastern Mississippi to: (I) better understand the hydrogeology and the ground-water flow in the aquifers, and (2) use a ground-water flow model to simulate existing water-level data for prepumping and pumping conditions, and use the model simulations to project the possible effects of increased ground-water withdrawals.
Case Study for Environmentally Sensitive Channel Design
Year: Authors: Smith T.S.
The lower 3.5 miles of Black Bayou was enlarged by the Black Bayou Drainage District in the mid-1940s to provide increased flood protection for the area. As a result of this construction, eight oxbows were formed within this reach. Of these, six are contained in a whole or part within Leroy Percy State Park. Many of these oxbows have remained partially open to Black Bayou and provide some measure of relief through conveyance of overbank flood flows.
Formulation of a Water Quality Index Using Continuous Weight Functions
Year: Authors: Sherrard J.H., Sii H.I.
Ott (1978) classified water indices in the literature into four general categories: general, specific-use, planning, and statistical. The National Sanitation Foundation (NSF) made one of the pioneering attempts to study water quality indices (Inhaber 1976). Their general water quality index (WQO was developed in 1970 using a formal procedure based on the Delphi technique (Canter 1985; Ott 1978). This WQI, based on evaluating the quality of natural waters, was composed of nine constituents: dissolved oxygen, fecal coliforms, pH, biochemical oxygen demand, nitrates, phosphates, temperature, turbidity, and total solids. The range of the WQI is such that the value 100 represents a perfect water, and zero a water that is unfit for the use intended without further treatment or modification. Many indices were developed in the 19708, but none has been accepted as a national water quality index. The need for 165 developing a uniform method for measuring the results of water pollution control programs has long been recognized by civil and environmental engineers (Brown et aI. 1970). The United States Environmental Protection Agency (EPA) is working on improved methods for measuring changes in water quality because the public desires concrete answers to their questions about water safety and because of demands that EPA adopt a uniform water quality index.
Evapotranspiration and Deep Percolation Losses in Flooded Rice
Year: Authors: Pringle, III H.C.
A three-year study is being conducted to determine minimum rice water requirements under this region’s environmental conditions, varieties, and soils. The objectives of this study are to: 1) measure ET from several rice cultivars during flood; 2) measure deep percolation losses from several soils during the flood period of rice. and 3) model water use (ET & deep percolation losses) of rice from weather, variety, and soil data. This paper will present data from objectives 1 and 2.
Land Application of Municipal Wastewater: Design Based on Climatic Criteria
Year: Authors: Pote J.W., Wax C.L.
The amount of effluent flow in a land application system increased when precipitation occurs, while at the same time the net water requirement of plans decreases. Therefore extra storage and extra land acreage is needed, but the amounts required have not been established. Additionally, frequent rainfall coupled with high humidity create an evaporation regime in the coastal region that inhibits the efficiency and viability of the land applicationdisposal method. The bases of these problems are climatologica; therefore, a climatological analysis provides design considerations regarding the capability of this disposal method in the coastal region. The objectives of this research were to: 1) develop analyses that account for climatological constraints in design of land application methods of wastewater disposal in the coastal region; 2) demonstrate this approach at a location in that region; and 3) define design criteria with varying probabilities of failure for this location.
Red River Waterway: Developoment for Commercial Navigation
Year: Authors: Pinkard, Jr. C.F., Dye P.D.
The Red River, after rising in eastern New Mexico, follows an easterly path across the panhandle of Texas, forms the boundary between Texas and Oklahoma, and extends into southwestern Arkansas. Once in Arkansas, the Red River makes a southeasterly tum through central Louisiana to its mouth at the Atchafalaya River just west of the Mississippi River. Along its path, the Red River cuts through soils rich in iron oxide. This iron oxide gives the Red River its rusty color, and hence its name. The Red River is an incised channel with the 50-year frequency flood basically contained within top bank. During the late 1800s, the great Red River raft was removed. This raft consisted of a large log jam that extended some 150 miles upstream from near Natchitoches, Louisiana, to the Arkansas-Louisiana state line. The raft created a backwater effect that induced sediment deposition. The removal of the raft resulted in significant bed degradation. Approximately 15 feet of degradation occurred at Shreveport. Also, channel improvement on the Atchafalaya River potentially has contributed to the bed degradation on the lower Red River. In its natural state, the Red River is a high energy system characterized by high velocities, actively caving banks, and shifting sand bars. This bank caving serves as the primary source for the large suspended sediment load carried by the Red River.
Use of Regression Analysis to Evaluate Water Level Changes in the Mississippi River Alluvial Aquifer
Year: Authors: Pennington D.A., Stiles M.
Agriculture and the economy of the Mississippi Delta of Mississippi have developed a critical dependence upon the limited water supplies of the region. In the last 25 years, agriculture water use has grown with the rice and catfish industries and the irrigation of cotton and soybeans. Most of the water used for agriculture is withdrawn from the Mississippi River Alluvial Aquifer. The heavy use of this resource is resulting in relatively consistent declines in some areas of the aquifer. The US Geological Survey began monitoring water levels in a network of wells located across the Delta in the early 19808. Today water levels in the 380 well network are measured twice each year by Mississippi Department of Environmental Quality. There is now a 10 to 13 year water level history available on most of those wells.
The National Water-Quality Assessment Program and the Mississippi Embayment Study Unit
Year: Authors: Mallory M.J.
This paper presents an overview of the National Water-Quality Assessment (NAWQA) Program, the Mississippi Embayment study unit in relation to the national program, and the environmental setting and major water-quality issues in the Mississippi Embayment study unit. The Nationl’s water reosurces are composed of many interrelated ground- and surface-water systems. The response of each of these systems to natural and anthropogenic factors manifests itself in a corresponding set of hydrologic, chemical, and biological characteristics that reflect the effects these factors have on water quality. Many national water-quality concerns arise from the recognition of recurring local and regional problems related to managing and protecting water quality.
Land Application of Poultry Wastes: Implications for Water Quality and Agroecosystem Management
Year: Authors: Kingery W.L., Wood C.W., Hall B.M., Miller M.S.
The objectives of the work reported herein were to: 1) Determine the effect of long-term land application of poultry wastes to pastures in the Sand Mountain region of Alabama on selected environmentally related soil chemical properties. 2) Determine the impact of poultry wastes on surface water quality. 3) Determine management effects on soil processes, such as nutrient transformations and leaching, as related to water quality.
Predicting the Persistence of Organic Pollutants in Natural Aquatic Systems by Using Kinetics Data of Microbial Transformation Processes
Year: Authors: Hwang H.M.
In assessing the potential exposure of humans and other organisms to toxic organic pollutants, it is necessary to first determine the persistence of the pollutants in the environment. This assessment, in turn, requires that we understand the kinetics of microbial transformation and complete mineralization (to CO,) of the compounds in a given ecosystem. Traditionally, models of pollutant transformation in aquatic ecosystems have usually assumed that degradation followed simple, Michaelis-Menten, kinetics which can be described by a single hyperbolic relationship between substrate concentration and degradation rate; i.e., the kinetics are defined by a single set of kinetic parameters which include a K1, (the substrate concentration supporting half maximal degradation rate) and a Vmu (the maximal rate of substrate degradation).
Use of a Constructed Wetland/Vegetated Strip System for Swine Wastewaster Treatment
Year: Authors: Cathcart T., Pote J., Triyono S., Crenshaw M.
A constructed wetland/vegetated strip system for the treatment of swine wastewaters has been in operation in Mississippi since 1991. The system (Figure 1) treats wastewater from an existing two stage lagoon system which receives waste from a farrowing house located at the Pontotoc/Flatwood Branch of the Mississippi Agricultural and Forestry Experiment Station (MAFES). The wetland/vegetated strip system was designed by Ross Ulmer of the USDA Soil Conservation Service and Don Hammer of the Tennessee Valley Authority. Day to day operation of the system, as well as data collection and analysis. has been conducted by personnel from MAFES, the Mississippi Cooperative Research Service, and Mississippi State University. The system is being operated to provide a "first look" at constructed wetlands performance in the treatment of swine wastewater. This paper will describe the physical system, its management, and results of the first 16 months of the evaluation.
Monitoring Nutrient Movement on Johnsongrass Plots Irrigated with Swine Lagoon Effluent
Year: Authors: Burcham T.N., Wren D.
Following are the overall objectives for completion of the entire project as defined in the proposal submitted to the Appalachian Regional Commission. I. To determine nutrient loading capacity of specific soils using effluent from a facultative swine waste treatment lagoon. 2. To determine yield response and nutrient removal of crops irrigated with swine lagoon effluent. 3. To determine influence of climatic variability, soil type, and management practices on irrigation scheduling. 4. Mathematically model the data observed in objectives 1-3. Incorporate mathematical models into a computer based decision support system. Since funding was secured late in the year (September of 1993), implementation of the field plots has been hindered and is not in place at this writing. However, during the wet winter months, instrumentation and flow measurement devices have been developed. The field plots will be installed during the summer of 1994. This report summarizes the basic experimental design and then describes progress made in the area of data acquisition, instrumentation, and flow measurement device development.
Assessment of Contaminant Levels in Fish and Shellfish from and the Gulf of Mexico
Year: Authors: Benson W.H., O'Neal J.M., Allgood J.C., Summers J.K.
The purpose of this investigation was to address these items of concern by conducting analytical chemistry evaluations which encompassed species (fish and shellfish) collected from the Gulf of Mexico. Specifically, this study represents the second year of data available for analytical chemistry evaluations from the EMAP - Near Coastal Project for 1992.
Alternative Methods for Geographic Positioning of Water Wells in the Mississippi Delta
Year: Authors: Belford G., Pennington D.A.
Accurate well locations are essential for management and planning of regional water resources. Well location is a required component of a Mississippi water use pennit. Well locations are also used in the development of alternative water supplies and may be used in upcoming aquifer modeling efforts. Good accuracy of well locations will improve the quality of these types of projects. Recent improvements in Global Positioning Systems (G.P.S.) have made it a practical and affordable tool for water resource managers.
Ultrasonic Assisted Removal of Suspended Water Contaminants
Year: Authors: Balasubramaniam K., Bolla S., Issa C.A.
In this paper, the studies involving the effect of agglomeration of suspended particles using high intensity ultrasound (greater than 1 w/cm2) will be discussed in detail. This approach will require the development of theoretical models to initially evaluate the optimal parameters for conducting the experiments. Initial experiements would include bench scale experiments. Based on the data collected, a prototype water cleansing pilot plan can be designed, developed, and tested.
Analysis of Streamflow in the Magby Creek Basin Near Columbus, Mississippi
Year: Authors: Floyd P.C.
This paper describes the results of a study in which a two-dimensional finite-element surface-water model was used to: 1) simulate the two floods of 1990 and the 50- and 100-year design floods for existing conditions; and 2) simulate the effects of a hypothetical floodflow diversion levee upon flows within the Magby Creek basin upstream from Lehmberg Road. Also included in the discussion are the general theory, data requirements, and techniques used to calibrate and verily the model selected for the flow simulations.
Catfish Water Use in the Mississippi Delta
Year: Authors: Hendricks M.W.
Over 95 percent of Mississippi’s catfish production is carried out in the areas served by the 17-county Yazoo-Mississippi Delta Joint Water Management District (YMD). All of that water is taken from the alluvial aquifer. With over 1650 permitted aquaculture wells within YMD District boundaries, previous estimates of water use may no longer be adequate for efficient resource management and planning. Water use information on catfish production has been collected indirectly. Interviews with catfish producers led the Mississippi Department of Environmental Quality to establish a permitted volume of 60 acre inches per acre per year for catfish production. Computer modeling indicated that it was possible for established ponds to use as little as 15 inches per year (Pote et al. 1988). This required a rainfall-capture management technique. The 6/3 method, as it is known, was tested on ponds in Leflore 58 county in 1991. Rodrigue et aL (1992) found that ponds managed by this method used 11 inches of the water compared to 22 inches used by traditionally managed control ponds in the test. The results were encouraging as to the reduction in water use by fine tuning management. The total water use figures for both the 6/3 managed ponds and the traditionally managed ponds were far lower than expected. The objective of the study reported in this paper was to directly measure the groundwater pumped at a number of randomly selected catfish production sites located throughout the Delta.
Investigation of Interactions Between Aquatic Microbial Assemblages and Mixed Contaminant Systems
Year: Authors: Hwang H.M., Loya J.
Microbial degradative activity in ground water of a chemical waste landfill site in Georgia and in ground water samples provided by an energy research site in California were the focus of this study. Bacterial numbers, microbial utilization of naturally occurring compcunds such as glucose, and kinetics of microbial mineralization (aerobic and/or anaerobic processes) of several model pollutants (i.e., p-cresol and toluene) were determined. Effects of inorganic nutrients on microbial degradation of toluene, p-cresol, and phenol in ground waters were also evaluated.
Application of Multi-Dimensional Finite-Difference and Finite-Element Grids in Estuary and River Modeling
Year: Authors: Jin K.R., Hasson J.K.
Hydrodynamic modeling is governed by non-linear fluid dynamics equations which, in successfully describing the fluid properties, cannot be solved in an analytical manner. Therefore, various approximation techniques such as finite difference, finite volume, and finite element methods have been utilized to help in solving these equations. These techniques require the generation of a grid over the entire flow field. This is often the most time-consuming portion of the whole field solution exercise, especially if the field geometry is complex as is the case with the coastal boundaries of water bodies.1
Freshwater Withdrawals in Mississippi, 1990
Year: Authors: Johnson P.M.
This report describes freshwater withdrawals from ground- and surface-water sources in Mississippi in 1990 in eight water-use categories: irrigation; aquaculture; thermoelectric pcwer; public supply; industrial and mining; domestic; commercial; and livestock. The categories are discussed in order, beginning with the category with the largest total freshwater withdrawals. Water-use withdrawals are rounded to two significant digits. Percentages are calculated from unrounded numbers.
New Regulations for Municipal-Solid-Waste-Landfills to Protect our Groundwater
Year: Authors: Jones L.F., Walters J.V., Greening L., Jefcoat I.A.
From these developments there has emerged the concept of designing a landfill so that the waste is enveloped by a barrier system which, ideally, would isolate it from the local environment. Some of these developments have occurred, to some degree, in all states. However, the designs of and operating practices for municipal-solid-waste landfills (MSWLFs) vary greatly among the states and within each state. Although variations will remain, new federal regulations will require all landfills that dispose of municipal solid waste (MSW) to meet minimum nationwide standards if they operate on or after 9 October 1993.
Augmentation of Low Flows of the Upper Sunflower River
Year: Authors: Pennington D.
The Delta region has become a large water user in the last two decades. Most of the increase in water use is associated with agriculture for crop irrigation and catfish production. The heavy use of the area’s water supplies has begun to cause concern. In some areas, the Mississippi River Alluvial Aquifer is declining at more than one-half foot per year and many stream base flows are also decreasing. The Delta is using more water each year than existing sources can supply. Two general areas of water resource problems that must be addressed are: 1) meeting the high water demand period for agricultural water use during the summer, and 2) maintaining stream fiows during extended dry periods for water quality reasons, including the need for wildlife and fisheries habitat.
Bioremediation of Polluted Subsoils for Protection of Groundwater Supplies
Year: Authors: Prewitt M.L., Borazjani A., Templeton M.C.
Groundwater constitutes a significant water source in most areas of the United States with approximately one-half of the residents relying on groundwater that has not been treated or disinfected and is often contaminated with organics. Sources of groundwater contamination include spills or leaks from storage tanks or pipelines, improperly constructed waste disposal sites, and applications of agricultural chemicals (1, 2). Two widely used classes of chemicals that have found their way into the subsoil and groundwater as a result of woodtreating operations include the polycyclic aromatic hydrocarbons (PAHs) and chlorinated phenols such as pentachlorophenol (PCP). These contaminants have been linked to health problems such as cancer, damage to the liver, kidney, and central nervous systems and, therefore, warrant attention. According to the Environmental Protection Agency, the PAH compounds have polluted more U.S. groundwater drinking supply by volume than has any other class of chemicals (3). Cleanup efforts have failed to keep pace with this toxic contamination, in part because many of the physical and chemical properties of groundwater, subsoils, and the aquifers remain poorly understood. In recent years a cleanup technology called bioremediation has been developed for contaminated soils and groundwater which uses microorganisms found in soil to degrade organic pollutants (4). By adding nutrients and other materials to the soil, large populations of adapted microorganisms can be developed that will rapidly degrade these organic pollutants. These techniques have been successfully used to clean up contaminated groundwater in situ (5, 6). This study was the final part of a four phase investigation to determine the conditions required to increase the population of microorganisms in the soil in order to maximize degradation of organic pollutants. Phase one determined that the addition of inorganic nutrients such as nitrogen, calcium, and phosphorus affected different soil types in different ways. Phase two determined that the addition of oxygen was best achieved with pressurized air as opposed to hydrogen peroxide. Phase three determined that the indigenous microorganisms were just as effective in degrading the PAHs and PCP as was a known PAH and PCP degrading bacteria. This paper reports the results of the final phase of this study in which effects of soil, air, and porosity on bioremediation of PAHs and PCP were evaluated.
Preliminary Trend Analyses of Stream Discharge and Sediment Data for the Demonstration Erosion Control Project, North-Central Mississippi, July 1985 T
Year: Authors: Rebich R.A.
In 1984, Congress directed the U.S. Army Corps of Engineers and the U.S. Department of Agriculture, Soil Conservation Service, to establish demonstration watersheds to address critical erosion and sedimentation problems. The Demonstration Erosion Control (DEC) Project is in the Yazoo River basin in north-central Mississippi. It is part of an ongoing joint-agency program of planning, design, construction, monitoring, and evaluation to alleviate flooding, erosion, sedimentation, and water-quality problems by applying environmentally sound management practices in several watersheds located in the bluff hills above the Mississippi River alluvial plain.
Managing Water Resources Data with Limited Resources
Year: Authors: Stiles M.
The Yazoo Mississippi Delta Joint Water Management District is a local governing authority that encompasses all or part of 17 counties in Northwest Mississippi. The district is concerned with both water quality and quantity issues in the Delta. One of the main functions of the district is the permitting of all water use points. A permitted water use point is any well with a casing diameter of 6 inches or greater or any surface water withdrawal. The Delta currently has approximately 80 percent of all permitted water use points in the state (Figure 1).
Effects of Infiltration on a Climatological Plan to Conserve Groundwater Aquaculture
Year: Authors: Wax C.L., Pote J.W.
A predictive model which allows for the possibility of infiltration losses is necessary to analyze the long-term impact of various water conservation management practices. This study compares the effects of rainfall, evaporation, and infiltration on the groundwater pumping requirements for soils of both low and intermediate infiltration rates. Both the common "Maintain Full Method" and the new "6/3 Scheme" are examined as management options to conserve groundwater.
Impact of Vegetative Filter Strips on Herbicide Loss in Runoff from Soybeans
Year: Authors: Webster E.P.
In this research, the potential for contamination of surface waters through agricultural runoff by two prominent soil-applied herbicides will be evaluated. These herbicides will be applied to plots using conventional tillage practices with soybeans planted in a monocrop and doublecrop (behind soft red winter wheat) production program. Additional plots will have no-till soybean production following winter wheat. Herbicide loss from each of these three soybean cropping systems will be evaluated with and without 45 the presence of tall fescue filter strips. Research results will provide information on potential herbicide losses from various tillage systems and will also indicate the overall ability of these grass filter strips to reduce losses. These results will provide key information which can be utilized in recommending conservation programs which reduce sediment losses while eliminating or reducing the potential for off-site movement of herbicides.
Microbial Removal of Sodium Selenite from the Culture Media by Bacillus Subtilis
Year: Authors: Wang W.H., Yang J.R., Buchanan B.B., Leighton T.
The primary purpose of the current study intended to examine the capability of various strains of B. bacillus to remove selenite from the medium and the mechanisms related with the removal of selenite. In addition, this study intended to examine whether these mechanisms were controlled by gene or not by using mutagenic treatment to test whether selenite-sensitive mutants could be induced.
Evaluation of Tissue Residues for the Environmental Monitoring and Assessment Program Near Coastal - Louisianian Demonstration
Year: Authors: Benson W.H., O'Neal J.M., Allgood J.C., ElSohly M.A., Summers J.K.
The Environmental Monitoring and Assessment Program (EMAP) is a national program developed by the U.S. Environmental Protection Agency in response to the need for information about the degree to which existing pollution control programs and policies protect the nation’s ecological resources. EMAP - Estuaries represents one portion of EMAP’s efforts in near coastal environments. These efforts are designed to provide a quantitative assessment of the regional extent of coastal environmental probiems by measuring status and change in selected condition indicators. The Louisianian Province Demonstration Project, which focuses on the Gulf of Mexico, provides a mechanism by which cooperators can collect and assemble environmental data relevant to the Gulf.
Water Balance/Water Management of the Tenn-Tom Waterway
Year: Authors: Burkett E.B.
The completion of the Tenn-Tom Waterway affected the flows experienced in the Tombigbee River Basin. The drainage areas and geography of the upper portion of the East Fork Tombigbee River has been particularly modified by the construction of the navigation project. The waterway from near Amory, Mississippi, to near Belmont, Mississippi, is called the Canal Section. This segment of the waterway consists of a dike and excavated channel. Five locks and dams raise the water surface from 190 to 330 feet above sea level. A divide cut connects the Canal Section of the waterway to the Tennessee River near luka, Mississippi. Bay Springs Lock and Dam, constructed across Mackeys Creek at the southern terminus of the divide cut, impounds Bay Springs Lake at the elevation of Pickwick Lake on the Tennessee River. The River Section of the waterway is a conventional siackwater navigation system. There are four locks and dams in the river section of the waterway raising the water surface from 73 to 190 feet above sea level. All three sections of the waterway have had unique impacts on the flow regime of the Tombigbee River.
Methods for Geographic Positioning of Water Wells
Year: Authors: Burt R., Zitta V.L.
To further emphasize the need to update the data bases, 25 wells within the Starkville quad are tabulated in Table 1. Compared to the "MSU" horizontal position determined by pacing-plotting-digitizing, the mean error of the MSDH data base is 570 feet with a standard deviation of 416 feet. The USGS well locations have a mean error of 505 feet with a standard deviation of 374 feet and the BLWR wells have a mean error of 479 feet with a standard deviation of 1064 feet. In Table 2, the wells within the data base on the West Point quad show a similar magnitude of error. These errors are greater than the 1 second in horizontal position deemed to be minimum in this study.
The Mississippi Hydrologic Information System Hardware and Software Implementation
Year: Authors: Cash S.
It was recognized by the technical staff of the Mississippi Department of Environmental Quality (DEQ), Office of Land and Water Resources (OLWR), that there was a need to implement a Geographic Information System (GIS) in order to better manage the hydrologic data of the state of Mississippi. There were many reasons that led to the decision to implement GIS technology at the OLWR, all of which were unified by the need to effectively access and manage geographic and hydrologic location related information. In the past, information critical to the mission of the OLWR was often inaccurate or incomplete, data sets were becoming increasingly difficult to manage because of the volume of paper involved, and maps were becoming increasingly difficult to interpret due to the quantity of attributes on each map. The need to resolve these problems into manageable assets was the fuel that drove the process of GIS implementation.
A Survey of Dairy Farms of Pike and Amite Counties of Mississippi Impact of Dairy Waste on Water Quality
Year: Authors: Edney N., Rizvi M., Rizvi N.F., Gibbs J.
Wastes from animal production are a significant component of agricultural Non-Point Pollution Source (NPS), for example, a 100 cow dairy herd produces as much fecal maner as a community with a population of 15,000 (Myers 1985). Thus a dairy facility with a herd of 100 cows would generate waste equivalent to waste produced by five towns of the size of Port Gibson, MS (population 3,000). The availability of these estimates associated with their reports related with nutrient over-enrichment in the bays, estuaries, and margin of the Gulf of Mexico has focused anention on the significance of agricultural Non-Source Pollution (NPS) in the Tangipahoa River basin of Southwest Mississippi. A number of state and federal agencies are actively involved in providing assistance for on farm nutrient management and development of best management practices (Myers 1985).
Constructed Wetlands as an Alternative Technology for Advanced Wastewater Treatment
Year: Authors: Leszczynska D., Dzurik A.A.
This paper gives an introduction to the design of artificial wetland systems and provides the results of a research project undertaken on a large constructed wetland facilities in central Florida. The Experimental System, comprised of 120 ha of artificial and natural wetlands. was designed as a receiver for secondary treated wastewater. The facility is located in Orange County, Florida, on the periphery of Orlando.
Effects of Irrigation Withdrawals on Base-Flow in the Flint and Apalachicola Rivers
Year: Authors: Dzurik A., Leszczynska D., Leitman S.
Base-flow in the Apalachicola River is important for the provision of a federally authorized navigation project and for the ecological functioning of its estuary. This paper investigates the impacts of irrigation activities in the Flint River on base-flow in the Apalachicola River.
Rice Water Use in the Mississippi Delta
Year: Authors: Cooke, Jr. F.T., Caillavet D.F.
In 1990, a contract between MAFES, Stoneville, and the Yazoo-Mississippi Delta Joint Water Management District was entered into where well water use would actually be measured. This work identified three factors which explained problems with the data taken in 1988. First, irrigation wells in the Mississippi Delta yielded 15 to 30 percent less water than producers indicated. Secondly, hours of annual use as estimated by farmers was shown to be considerably less than what they reported. The third factor was that during the 1988 growing season rainfall was poorly distributed requiring considerably more operation of wells than usual.
Monitoring Lateral Movement and Stability of Channel Banks on the Pearl River in Mississippi
Year: Authors: Turnipseed D.P., Smith J.A.
The overall purpose was to develop methodology to assess past channel movement and current bank stability and correlate this information with recorded floods that probably initiated and provided the driving force behind much of the historical bank movement at these sites. The methodology may be used in future studies to estimate future bank erosion, but no attempt is made in this paper to predict channel meandering at the study sites. The focus of this paper is to document historical changes in the channels and pattems of change at the sites.
Practical Hydrologic Considerations for Flood-Control Storm-Sewer Designs in Mississippi
Year: Authors: Walters J.V., Jones L.F.
Those NWS studies are based upon the data from all of the rainfall-observation stations of long record that are pertinent to the geographic areas to which each report pertains. The data analyses and syntheses of those reports have yielded isopluvial maps that provide statistical predictions of pertinent rainfall amounts for areas among rainfall-gaging stations even though they did not contain such stations of long record at every point of possible interest. The more than a hundred pages of those reports preserve the essence of the pertinent rainfall data that are available for the United States, but the information is not in such form or condition that allows its use by Mississippi designers most easily. The authors used data and algorithms supplied in those studies to develop intensity-frequency-duration rainfall data for ten Mississippi cities. The cities were selected to cover the state geographically and to give preference to centers of population to the extent possible.
Preferential Flow Estimations to a Subsurface Drain with Bromide Tracer
Year: Authors: Cullum R.F.
Ground water contamination by agricultural chemicals has been reported in over 800 of the 1437 counties in the U.S. (National Research Council 1989). This may indicate a significant adverse impact on the environment. The need for more research and management practices that produce profitable yields while minimizing environmental contamination is great. Pesticide use in agriculture has increased dramatically. Currently, one billion kilograms of more than 400 different types of pesticide chemicals are sprayed each year on America’s croplands (National Research Council 1989).
Causes of Erosion, Erosional Rates, and the Impact in Southeast Coastal Mississippi
Year: Authors: Eleuterius C.J., Criss G.A.
Coastal erosion is responsibIe for substantial losses of natural resources in the extreme southeast corner of Jackson County, Mississippi. This area of bays, bayous, and marshes (Figure 1) is comprised of Point aux Chenes Bay, Bang’s Lake, Middle Bay, Bayou Cumbest, Heron Bayou, west Grand Bay, and the contiguous marshes and uplands. For convenience, this coastal marine system will herein henceforth, be referred to as "Polnt aux Chenes" this is Mississippi’s only remaining pristine estuarine subsystem and has considerable economic and social value. Essential for prudent planning to reduce or prevent further coastal erosion al Point aux Chenes requires identifying the erosive forces and understanding their contributions to the erosive processes.
Reformulation of the Upper Steele Bayou Project Yazoo Basin, Mississippi
Year: Authors: Johnson D.
Since 1989, the U.S. Army Corps of Engineers, Vicksburg District, has been reformulating the remaining unconstructed segments of the Upper Steele Bayou Project in the Yazoo Basin, Mississippi. An array to alternative plans, emphasizing increasing urban fIood protection, reducing agricultural intensification, and Iessening adverse environmental impacts, has been evaluated. The draft reformulation report was in December 1991.
From "Nonpoint" to "Point," and What is the Point?
Year: Authors: Jones L.F., Walters J.V.
Rainfall picks up a multitude of pollutants as a result of its falling on and draining off streets and parking lots; construction and industrial sites; and mining, logging, and agricultural areas. The runoff, storm water discharge, with its accumulated pollutants, eventually flows into surface water bodies such as creeks, rivers, estuaries, bays, and oceans. Many recent studies have shown that runoff from urban and industrial areas typically contains significant quantities of the same general types of pollutants that are found in wastewaters and industrial discharges and often causes similar water quality problems. These pollutants include heavy metals (e.g., chromium, cadmium, copper, lead, mercury, nickel, and zinc), pesticides, herbicides, and synthetic organic compounds such as fuels, waste oils, solvents, lubricants, and grease.’ These pollutants can cause problems for both human health and the aquatic ecosystems supported by the diverse receiving water bodies.
Record High Rainfall in Mississippi During the Period of December 1990 Through May 1991
Year: Authors: Long L.G.
Flooding problems continue to plague the floodplains of river basins in most areas of the state, even though numerous flood control and flood prevention measures have been installed by federal, state, and the private sector. This paper illustrates just how vulnerable Mississippi is to the unusual and persistent weather patterns that caused the widespread and extensive rainfall events in the state between December 1990 and May 1991.
Ground-Water Information Data Base for Mississippi Maintained by the U.S. Geological Survey
Year: Authors: Oakley W.T.
The U.S. Geological Survey (USGS) investigates the quantity, quality, distribution, and movement of the ground-water resources in Mississippi. The large amount of hydrologic data collected during these investigations provides valuable information that can be used to evaluate ground-water trends and conditions. The Ground-Water Site Inventory (GWSI) is the computerized storage and retrieval system for groundwater data collected by the USGS and others. The system provides an easily accessible file of information about site (well) locations, well construction, and geohydrologic characteristics for about 67,000 sites in Mississippi. This information can be used to identify potential water-resources problems, to develop background information for ground-water investigations, and to study ground-water response to natural climatic variation and induced stresses.
Water Management in Aquaculture Ponds: Use of Rainfall Through Field Application of the 6/3 Method
Year: Authors: Rodrigue P.
This paper will discuss the application of the 6/3 method on commercial production ponds, including results, implementation problems, and recommendations for application on a large scale.
Development of a Water Quality Model for the Upper Tennessee-Tombigbee Waterway
Year: Authors: Truax D.D., Shindala A., Jin K.R.
The water quality model previously used by OPC for waste load allocations may not accurately assess the water quality response of the Tenn-Tom. This is due, in part, to the complex hydrologic and geometric characteristics of the waterway and the simplified kinetic formulations incorporated into the existing model. It thereby seems necessary to develop a new water quality model that can accurately describe the waste assimilative capacity, and thus the waste allocation of the Tenn-Tom which constitutes the primary objective of the work reported here. The secondary objective of this work was to define the existing water quality within the waterway.
Pesticide Concentrations in Shallow Ground Water and Surface Runoff for Land Cropped to Conventional- and No-Till Soybeans
Year: Authors: Smith, Jr. S.
Increasing detections of agrichemicals in our Nation’s aquifers have raised questions regarding the environmental costs of recommended farming practices such as conservation tillage. Conservation tillage practices initially require an increased use of herbicides to control weeds that are usually controlled with conventional tillage practices. Additionally, increased infiltration generally associated with conservation tillage is of concem because of the potential increased threat of contamination of these aquifers with agrichemicals. Information about the effects of conservation tillage practices on ground and surface water quality is lacking for most of Mississippi, particularly the Ioessial uplands in the northern part of the State. This paper discusses the USDA-National Sedimentation Laboratory’s continuing efforts in this important research area and presents some of the findings to date regarding pesticide transport. Informatlon about nutrient transport, water movement, and field instrumentation is presented in companion papers (Schreiber 1992; Cullum 1992).
Evaluation of Humic-Pesticide Interactions on the Fate and Effects of Agricultural Chemicals
Year: Authors: Benson W.H., Kadlec M.C., Long S.F., Ortego L.S., Wang Y.
The majority of water qualify standards presently are based on the toxicity of chemicals to organisms exposed on clean laboratory dilution water. ThIs rationale does not take into account the interaction of chemicaIs with naturally occurring organic compounds found in aquatic ecosystems. Dissolved humic materials (DHMs) are ubiquitous components of the chemical matrix of freshwatert ecosystems and can affect the availability and toxicity of chemicaIs in the environment.
Overview of the Cockfield and Sparta Aquifers in the Jackson Metropolitan Area, Mississippi
Year: Authors: Arthur J.K.
As part of the Federal-State Cooperative Program, the U.S. Geological Survey and the Mississippi Department of Environmental Quality, Office of Land and Water Resources, began a study in 1987 of the Cockfield and Sparta aquifers in Hinds, Madison, and Rankin Counties in west-central Mississippi (fig. 1). The purpose of the cooperative study is to provide State and local officials with the hydrogeologic information concerning the Cockfield and Sparta aquifers needed to manage the ground-water resources of the three-county area. An important part of this study Is the development of a digital ground-water flow model of the Cockfield and Sparta aquifers for use as a tool to gain a better understanding of the flow dynamics and optimum water yielding capability of the two aquifers in the area. This paper presents a brief overview of the Cockfield and Sparta aquifers in the study area and is based largely on information assembled to develop the digital flow model of the two aquifers.
Status of Saline Water Occurrence within the Cockfield and Sparta Aquifers, Washington County, Mississippi, 1991
Year: Authors: Carter J.H.
High chloride levels in the aquifers of Washinqton County have been recognized since the early 1900’s. High chloride occurrence was first documented in a report by G.F. Brown (1947) and later in a report by Taylor and Thomson (1971). In 1987 BockeImann mapped several variations in chIoride concentrations (BockeImann 1987). The primary objective of this study is to determiine if there has been a significant increase in the chloride levels in the Cockfield and Sparta aquifers of Washington County since the 1986 water-quality study. Secondary objectives include establishing both a basis tor future water quality studies and a network of wells to monitor local groundwater levels. Methods of study include interpretation ot E-Logs, water-level measurements, and water-sample collection.
Interaction Study of the Sunflower River and the Mississippi River Valley Alluvial Aquifer
Year: Authors: Bryant C.R.
The continuing declines of water levels in the aIluviaI aquifer and the extremely low fIows of the past few years in some of the Delta streams prompted this study to examine the relationship between the surface- and ground-water systems. In cooperation with the United States Geological Survey, twenty-two 2-inch diameter observation wells (piezometers) were drilled, forming four lines (Figure 1). Two of these lines are located near Doddsville, with one line on each side of the river. Each line consists of seven piezometers and extends approximately 1800 feet perpendicular to the river. The other two lines are located near the town of Sunflower, again situated on each side of the river. Each line consists of four piezometers which extend 100 feet perpendicular to the river. The average depth of lthe piezometers is 50 feet, the lower 10 feet of which penetrates the upper sands of the alluvial aquifer.
Removal of Heavy Metal Ions from Oily Wastewater
Year: Authors: Daugherty J.E.
Oily wastewaters are generated by manufacturing processes where machine coolants, hydraulic fluids, and aqueous degreasing solutions come into contact with rinsewater. The ideal wastewater treatment segregates oily wastewater from metal ion bearing wastewater, but in operations of the type just mentioned this is sometimes impractical and the metallic wastewater may already be oily anyway. This presentation is a case study of lessons learned during one attempt to successfully treat oily wastewater which contained both metal ions and oil in quantities over the discharge limits.
Simulation of Travel Time for a 300 Cubic Foot Per Second Discharge from Okatibbee Reservoir, Pascagoula River Basin, Mississippi
Year: Authors: Floyd P.C.
Surface-water withdrawals in Jackson County, Mississippi, are primarily from the Pascagoula River at Cumbest Bluff near Three Rivers, Mississippi (fig. 1). Increasing water use is placing a burden on this supply, and demand can exceed supply during periods of extreme low flow. A possible solution to this problem is to augment extreme low flows with discharges of water from Okatibbee Reservoir in Lauderdale County, Mississippi. The first step in assessing the feasibility of this proposal is to estimate the travel times of flow releases as they travel the 252 mile reach from the Okatibbee Reservoir spillway to Cumbest Bluff (fig. 1). For purposes of this report, travel time is the time in days for the leading edge of an additional volume of water (in excess of base flow) to the river system to travel from one point on the reach to another. This additional discharge can be from rainfall or reservoir releases. As a result of discussions with officials from various governmental agencies, a simulated discharge of 300 feet3/s (cubic feet per second) from Okatibbee Reservoir was used to analyze the effects of reservoir releases on the lower Pascagoula River. This paper presents the methods used !n estimating the travel time, and the results of these estimates, for the flow release from Okatibbee Reservoir to travel through the Pascagoula River basin to Cumbest Bluff during low-flow conditions.
Effects of the Paleozoic-Cretaceous Unconformity on the Aquifers of Northeast Mississippi
Year: Authors: Jennings S.P., Hoffmann J.H., Phillips P.A.
As will be illustrated in this paper, the PaleozoicCretaceous unconformity significantly influenced the thickness and lithologic character of the lower part of the Upper Cretaceous stratigraphic section and the potential of the Paleozoic rocks as aquifers. The effects of the unconformity are seen on both regional and localized scales. This paper presents some preliminary observations and interpretations of the nature and significance of the unconformity in a portion of northeast Mississippi as part of an on-going effort by the Mississippi Oflice of Land and Water Resources to describe the hydrogeology of the region. The results of this study will eventually be utilized in the development of a regional ground-water flow model and in ground-water resource management. This paper augments and builds upon the work of many previous authors.
Producing Safe Drinking Water is not Easy
Year: Authors: Jones L.F., Walters J.V.
Public concern for the presence in water of chemicals which might cause adverse health effects after longterm exposure appears to be greater than the concern for the presence of microbial agents which can cause illness within two weeks of exposure. Yet the practice of treating water to make it safe for drinking began because of the need to control the transmission, by water, of microorganisms which cause disease. Production of drinking water that is safe microbiologically is still the primary public health concern of the drinking water industry. However, despite remarkable progress in the improvement of water treatment, outbreaks of waterborne disease still occur with disturibing frequency.4
Uses and Misuses of Aquifer Data and Models
Year: Authors: Nuzman C.E.
Public decisions regulating or restricting the use of groundwater must be based on extensive hydrologic study with due consideration to all input parameters, not fragmentary points of data that are unrelated. The appropriate data base includes estimates of total annual pumpage with corresponding water level measurements taken in a short period of time, over several years, and Iong-term water quality monitoring from wells of known condition. Even newly constructed wells can be drilled near old abandoned boreholes whose Iocation was lost in time and give uncharacteristic data for the area.
Accelerated Erosion in the Bayou Pierre Basin, Southwest Mississippi: Characterization and Causes
Year: Authors: Patrick D.M., Mao L., Ross S.T.
The purpose of this paper is to describe the results of on-going investigations of accelerated fluvial erosion and concomitant geomorphic change occurring in the upstream reaches of the Bayou Pierre basin of southwestern Mississippi. Erosion is accelerated when substantial geomorphic change occurs rapidly over a few years or decades, when it results in geomorphic changes in channel morphology which are more profound than changes in meander form, and when it produces general fluvial instability ina stream basin. The studies reported here are a part of basin-wide research which was initiated because of concern that erosion and related sedimentological processes are adversely affecting stream habits and the viability of the "threatened" bayou darter (Etheostoma rubrum) which is endemic to this basin (Teels 1976; Burris and Bagley 1989). morphology whICh are more profound than changes In meander form, and when it produces general fluvial Instability in a stream basln. The studies reponecl here are a pan 01 basin-wide research whICh was irwtiated because of concern that eroSion and related sedimentological processes are adversely aHeeling stream habits and the vlabiUty 01 the "threatened" bayou daner IEtheostoma n,!bfuml which is endemic to this basin (Teels 1976; Burris and Bagley 1989).
Monitoring Scour at the State Highway 15 Bridge Across the Leaf River at Beaumont, Mississippi
Year: Authors: Wilson, Jr. K.V.
Scour of channel-bed material around bridge piers and in the vicinity of bridges is a potential problem that must be considered when constructing bridges spanning waterways. Erosive action of flowing water may expose or undermine bridge-pier and bridge-abutment foundations and thereby induce structural failure. Accurate estimates of potential scour are essential in the design, construction, and maintenance of bridges. The collection of scour data at bridge sites during floods provides a better understanding of scour and provides the information necessary to improve methods that can be used in bridge design to estimate scour. Because of the difficulty of obtaining scour dala around bridges during floods, few data have been collected.
The U.S. Geological Survey and Tuscaloosa Cooperate to Protect our Premier Water Supply
Year: Authors: Walters J.V.
Tuscaloosa is a city of about eighty thousand people in the southwest corner of the northern half of Alabama. Northport is the largest other city in the county, its population is about twenty thousand, and that of Tuscaloosa County, inclusive of the twin cities on the Black Warrior River is about one-hundred-fifty thousand. The majority of those people historically have been served by the public water supply of the City of Tuscaloosa.
Bioremediation of Polluted Subsoil for Protection of Groundwater Supplies
Year: Authors: Templeton M.C., Prewitt L.
The objective of this study is to determine techniques to increase the microorganism populations in the subsoil in order to maximize decomposition of organic pollutants in the subsoil. Polynuclear aromatic hydrocarbons and chlorinated phenols will be studied since these compounds are very common environmental pollutants and offer a wide range of chemical properties. Therefore, the results of the proposed study will be applicable to a variety of cleanup scenarios.
Instrumentation to Quantify and Sample Surface Runoff and Shallow Ground Water
Year: Authors: Cullum R.F., Schreiber J.D., Smith, Jr. S., Grissinger E.H.
Research is needed to determine the extent of chemical leaching to ground water as a function of tillage practices. Therefore, a field study was started to understand the relationships among agricultural practices (tillage and chemical application), surface runoff (soil erosion), and ground water pollution. The overall objectives of this study were to determine the role of macropore flow under three different tillage systems (conventional, conservational or minimum, and no tillage) on corn and to quantify the concentrations of pesticides and nitrate found in shallow ground water and in surface runoff so that practices could be developed to improve both ground water quality and surface runoff. The methods used to establlish these objectives are discussed below.
Software and Hardware Considerations for a Graphics Workstation
Year: Authors: Cash S.
To accomplish its research objectives the Office of Land and Water Resources plans to implement high tech computer alternatives in order to solve the water resource management problems of the State. At present, the Office is using microcomputers to accomplish these goals. In the near future, the Office intends to establish a workstation environment to fully accommodate the State’s needs.
The Establishment of a Constructed Wetland to Treat Wastewater from a Confined Animal Operation
Year: Authors: Strong L., Ulmer R.L., Cathcart T.P., Pote J.W.
Regardless of how wetlands are defined or described, their value as natural resource systems is becoming better understood as our knowledge of ecological processes increases. Scientists have discovered that wetlands are, in fact, natural assets that provide important benefits to people and their environment (USEPA 1988). One of the most important values of wetlands is their ability to help maintain and improve the water quality of lakes, rivers, and streams (USEPA 1988). Mississippi has an estimated 58,000 milk cows in approximately 720 dairy operations. It is estimated that only 50 percent of these have waste treatment facilities. The state of Mississippi allows continuous discharge and excess flow from animal waste lagoons which have the potential to degrade the water quality of receiving waters. Constructed wetlands may be an economical and viable component of animal waste treatment systems. A cooperative project between the Newton County, Mississippi, Soil and Water Conservation District; Mississippi State University; and the SCS to establish and evaluate a constructed wetland as part of an animal waste treatment system was initiated in 1989.
Herbicide Concentrations in Shallow Ground Water and Surface Runoff for Land Cropped to No-Till Soybeans
Year: Authors: Smith, Jr. S., Cullum R.F., Schreiber J.D., Murphree C.E.
Since ground water is the source of drinking water for about half the population of the U.S., these increasing detections of pesticides in our aquifers have raised questions regarding the environmental costs of farming practices such as chemigation and conservation tillage. The impact on ground water quality of USDA decisions that promote the use of conservation tillage to control soil erosion is of major 67 national interest and concern because: a) conservation tillage practices initially require an increased use of pesticides, particularly herbicides to control weeds that conventional tillage had previously controlled, and b) the higher infiltration rates generally associated with conservation tillage increase the potential of these pesticides to leach below the root zone to ground water (U.S. Department of Agriculture 1989; Leonard 1988). The USDA Research Plan for Water Quality has as its general goal the protection and enhancment of quality of the Nation’s surface and ground waters while sustaining agricultural activities. Emphasis is on effects of conservation tillage practices on surface and ground water quality, with the objective to develop economically and environmentally sound crop production systems. This information is lacking for most of Mississippi, particularly the uplands of northern Mississippi. This paper discusses the National Sedimentation Laboratory’s initial and ongoing efforts in this very critical research area and presents the pesticide data obtained thus far (i.e.,for the 1990 crop year). Nutrient resulls and details of field instrumentation are presented in companion papers (Schreiber et al. 1991: Cullum et al. 1991).
Tritium Analyses of Shallow Ground Water in Mississippi Spring 1989 and 1990
Year: Authors: Slack L.J., Oakley W.T.
One of the objectives of the Office of Pollution Control’s groundwater protection programs is to investigate the relative age of ground water in the principal aquifers in Mississippi that are associated with the Well Head Protection Program. In 1989 and 1990, in cooperation with the OPC, the USGS utilized radioisotope (tritium) dating techniques to assess the relative age of shallow ground water for selected aquifers in the State. This paper summarizes the site information, methods of sampling and analysis, results of the tritium analyses, and other selected water quality data collected as part of that study.
An Example of Model Utilization for Water Management Decisions in Mississippi
Year: Authors: Schweitzer R.E.
Model simulations were utilized to evaluate the effects of large withdrawals of water from Layer 2 on overlying and underlying model layers. Model-projected potentiometric surfaces for Layers 1 through 6 were simulated at two sites near Ocean Springs, MS. Although Ocean Springs at the present time withdraws freshwater from Layers 4 and 6, Layer 3 may be considered a potable water source for future use.
Plant Nutrients in Shallow Ground Water and Surface Runoff of a North Mississippi Soybean Watershed
Year: Authors: Schreiber J.D., Smith, Jr. S., Cullum R.F., Grissinger E.H.
Maintaining and/or improving crop production efficiency without adversely affecting environmental quality is a major challenge for U.S. Agriculture. Pesticide and nitrate-N contamination of ground water is a national problem that needs timely and rational solutions. Research worldwide has shown that the most extensive source of pesticides and nutrients delivered to ground and surface waters is agriculture. There is a great public concern about ground water quality since it is the source of drinking water for half of the U.S. In rural communities, nearly 95% of the population depend upon wells for drinking water. The emphasis during the 1960’s and 1970’s was on point source pollution and surface water; at this time, there is a great public concern about ground water quality which will probably be a primary water quality issue of the 1990’s.
Relationship Between Calcite Solubility and Chloride Content of Ground Water in the Paleozoic Aquifer, Alcorn County, Mississippi
Year: Authors: Saunders J.A., Swann C.T.
Chloride is the most conservative major ions in solution; it does not enter into redox reactions, does not form complexes with other ions unless present at elevated levels, is not easily adsorbed on mineral surfaces, and does not form salts of low solubility (Hern 1985). Because of these properties, and assuming no human-derived sources (e.g.. road salt). the chloride content of the ground waters in the Paleozoic aquifer in Alcorn County is not easily explained. For example, Feth (1981) states: "The contlnulng release of CI at rates that cause modest and virtually constant concentrations in some natural waters pose problems of supply mechanism that remain unanswered-indeed largely unexplored."
Legal Impediments to Stream Withdrawals During Droughts
Year: Authors: Sage A.
The topic of my talk was generated about four years ago when we had a severe drought. That was the year that the Department of Natural Resources, now the Department of Environmental Quality, had to tell some people to quit taking water out of some streams because they were going to get below the minimum stream flow. There was a lot of conversation about what to do. Farmers were concerned, especially rice farmers. They needed the water. You have to have a certain amount of soil moisture to germinate seed. It looked like a desert down through the Delta. One of the things that was mentioned was the Mississippi River sitting over there with all that water in it. Why don’t we pump some of it out of the river and jump pump it out over the levee and put in into the streams and let it flow on down through the Delta? There would be plenty of water for everybody.
Performance of Torpedo Grass (Panicum repens) in a Tertiary Treatment System for Pulp Mill Waste Water
Year: Authors: Reaves R.P., Howell F.G., Tettleton R.P.
One of the primary considerations for design specifications in this application is which plant or plants offer the best overall performance in water quality enhancement while requiring minimum maintenance. The purpose of this paper is to relate information and observations regarding performance and behavior of Panicum repens through two growing seasons in the Leaf River pilot project. Productivity and surface coverage were monitored as well as responses to the local climate, seasonality, and the impact of subfreezing temperatures. Additionally, competitive ability versus invading species was noted.
Evolution of a Database
Year: Authors: Phillips P.A., Jennings S.P., Hoffman J.H.
When attempting to assemble and manage the geologic and hydrologic information necessary to design and calibrate a computer model of a multilayered aquifer system, the first thing a hydrologist becomes aware of is the sheer, overwhelming mass of data that must be maintained. Latitude, longitude, elevation, formation tops, water levels -- all this and more must be gathered and updated as necessary. In this model area alone, which encompasses fourteen counties in northeast Mississippi, there are over 3000 wells which are being used as a basis for geologic and potentiometric maps. The obvious solution to this data management problem was the creation of a computer database.
Tennessee-Tombigee Waterway Canal Section Effect on Adjacent Bottomland Hardwoods
Year: Authors: Ulmer R.L.
Landowners, environmentalists, and project management personnel have all expressed concern as to what effect the Canal Section, with its operating water level above the adjacent floodplai~ surface, would have on the bottomland hardwoods. This paper presents a summary of a seven (7) year study by the Soil Conservation Service for the Corps of Engineers - Mobile District. The study was made in the bottomland hardwood floodplain adjacent to the Lock D Canal Section pool from 1982 through 1989 covering the pre-pool and full pool operating conditions.
What Shall We Do with Garbage-Dump and Landfill Leachate?
Year: Authors: Shih T.Z.
The objectives of the research reported in this paper were to study the regulations pertinent to solid-waste leachate, to consider the feasibility of leachate treatment at existing publicly owned treatment works (POTWs), and to simulate, through a program written in BASIC language, the oil-fired incineration of such leachate.
Potentiometric Surface of the Mississippi River Valley Alluvial Aquifer, 1981-1989
Year: Authors: Crawford J.L.
The Mississippi River Valley alluvial aquifer is the principal source of water used for irrigation and fish culture throughout the region of Mississippi known as the "Delta." Potentiometric maps generated biannually from water levels measured in the Delta since 1981 have been used to monitor seasonal fluctuations and annual changes in the aquifer. These maps show that significant water level declines have occurred in some areas of the Delta as a result of increased levels of pumping. Because of the dependence of the Delta on an avallable water supply from the alluvial aquifer, a finite-difference digital model (Sumner and Wasson 1984) was deveioped which can be used to simulate flow in the aquifer. The model will be utilized as a tool to assist in the management of the water resources in the Delta.
Effects of Clearing and Snagging on Physical Conditions of Rivers
Year: Authors: Smith R.H., Shields, Jr. F.D.
This paper describes a pilot study conducted as part of a larger research effort to develop techniques to quantify and predict incremental hydraulic and environmental effects of snag removal. The principal objective of the pilot study was to investigate effects of selective clearing and snagging on physical conditions and aquatic habitat in a sand bed river. Long-term research objectives are to relate the densities and types of woody debris in streams to: specifIC biotic parameters (species type and densities); conveyance (the ability of the river channel to transport water); and longitudinal dispersion (the tendency of a channel reach to trap and hold fine particulate matter).
Upstream Extent of Saline Water in the Pascagoula River
Year: Authors: Rebich R.A., Landers M.N.
The Mississippi Gulf Coast region has undergone rapid industrial and municipal growth since the 1940's. A substantial part of this growth has centered in the Pascagoula-Moss Point metropolitan area (Bednar 1978, p.S). The development of the ground-water resources in this region has caused long-term declines in both water levels and water quality. As a consequence, the development of a surface-water supply has been proposed to help meet future demands. The surface-water source that has the greatest potential for development is the Pascagoula River, which has a mean annual discharge of about 12,200 ft3/s (cubic feet per second), or 7,870 Mgal/d (million gallons per day), in the study reach. The lower reaches of the river is tidally affected and has a fairly typical "wedge" of saline-water intrusion from the Mississippi Sound. This report describes a multiple-least-squares regression equation that can be used to estimate the upstream extent of saline water in the lower Pascagoula River, information that wouid be helpful to water-resources planners and managers.
Ground-Water Models of the Miocene Aquifer System in Jones County, Mississippi
Year: Authors: Studivant, Jr. R., Patrick D.M.
The objectives of this research were to develop a better understanding of the Miocene aquifer system in Jones County, Mississippi; to document the historic drawdown of potentiometric surfaces in this region; and to develop three-dimensional, numerical simulation models of the aquifers. Particuiar attention was given to the population centers at laurel, Ellisville, and Sandersville. The Paleogene and deeper aquifers, and the shallow Citronelle aquifer were not a part of this study. This research was a part of a more comprehensive regional investigation dealing with the Miocene aquifers in Forrest and Lamar, as well as Jones County (Patrick and Zhao 1989; Patrick and others 1989).
Biotechnology Approach to Bioremediation
Year: Authors: Borazjani A., McGinnis G.D., McFarland L.K., Hannigan M.F., Hendrix F., Strobel D.A., Pope D.F., Rughani J.R.
The contamination of soii and water by wood-treating chemicals is a growing environmental concern in Mississippi and most of the southeastern United States. Two very common components of organic wood-treating wastes are polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP). From an economical standpoint, cleaning up the contaminated soil or water is very costly; however, from a biological standpoint, ignoring contamination could prove to be even more costly.
Legal Concepts in Water Management: Shaping the Law to Serve the Public Interest
Year: Authors: Griffith B.E.
In the context of responsible use, conservation and management of water resources, legal concepts don’t just happen. These concepts run the gamut from structural solutions, such as diversion of rivers and use of low water weirs, to management and conservation practices, such as tailwater return systems, erosion and sedimentation control, and nonpoint source pollution control, to federal and state environmental legislation and regulatory programs aimed at preventing or reducing water supply contamination. This presentation will accordingly focus on emerging and changing legal concepts which form the underpinnings of the recently organized YMD Joint Water Management District and which are being created and shaped to serve the public interest.
Rice and Furrow Irrigation Management
Year: Authors: Podrigue P.B.
Water use on rice fields has been monitored by the SCS since 1987. Three rice fields were monitored during the summer of 1989 to determine .how well water was managed on each. A total of 7 fields have been monitored which resulted in usable information. These results are summarized below. LL indicates the field had been precision leveled. P indicates permanent pads around the field borders. The amounts shown below do not include flushes.
Influence of Dissolved Humic Materials on the Biological Effects of Drilling Componenets
Year: Authors: Benson W.H., Stackhouse R.A.
In view of the contradictory nature of the available data, the objective of the present investigation was to evaluate the influence of OHM, humic acid (HA), on the toxicity and bioaccumulation of selected trace metals associated with drilling fluid components, cadmium and chromium. Chromium (Cr) was tested as hexavalent chromium (Cr VI) and two forms of trivalent chromium (Cr III), chromic chloride (CrCI3) and Cr Lig. Cr Lig is a form of Cr III used as a deflocculent to thin water-based drilling fluids, in addition to maintaining the fluidity of the drilling fluids (U.S. EPA 1985a). Although considerable information is availabie on the toxicological effects of drilling fluid components, such as Cr Lig, on the marine environment, there are few data concerning their impact on freshwater systems. Therefore, Cr Lig was used as a model compound to improve our understanding of the environmental behavior of drilling fluid components in freshwater ecosystems.
Interaction Between Yazoo River and Mississippi River Valley Alluvial Aquifer System
Year: Authors: Cooey J.
The purpose of this study is two fold. Understanding of the changes in historical and present hydrologic interactions between the waters of the Yazoo River and Mississippi River Alluvial Aquifer System is made possibie through analysis of all directly related data. Secondly, this initial study is intended to propose the best method for measurement and quantification of actual stream-aquifer boundary conditions.
What Can You Learn About Water Resources in Moscow, U.S.S.R.?
Year: Authors: Walters J.V.
During June of last year the author, with his wife, joined a small group of members of the American Society of Civil Engineers on a trip to the Soviet Union. The purpose was to attend a three-day, bilateral, water-quality conference in Moscow, the first joint conference sponsored by the USES of the U.S.S.R. and the ASCE. USES is their Union of Scientific and Engineering Societies. About two weeks of travel and inspection of some of their civil engineering facilities was planned for the American participants following the conference.
Influence of Greentree Reservoir Management on Overstory Composition, Canopy Density, and Hardwood Regeneration on Noxubee National Wildlife Refuge
Year: Authors: Young G.K., Karr B.L., Hodges J.D., Leopold B.D., Kaminski R.M.
Greentree reservoirs (GTRs) are modified bottomland forest sites at least partly enclosed by a system of levees which serve to impound water between late fall and early spring. Greentree reservoirs are primarily managed for migrating waterfowl, particularly mallards (Anus platyrhynchos) and wood ducks (Aix sponsa). Historically, bottomland forests in concert with natural flooding regimes have provided this necessary habitat; however, the dramatic decrease in Mississippi’s bottomland acreage and drainage and flood control projects have reduced the availability of this waterfowl habitat. It has been estimated that of the original 22.2 million acres of bottomland forests in the Mississippi deltaic plain only 5.4 million acres remained in 1978 (Fredrickson 1978). Between 1960 and 1975, Mississippi’s remaining bottomland acreage was reduced by an average of 20,000 acres per year (Turner et al. 1981). Loss of this habitat is attributed primarily to drainage and flood control projects by various government agencies (Fredrickson 1978, Harris et aI. 1984). These activities have allowed conversion of bottomland hardwood sites to agricultural and urban development interests. Klopatek (1979) reported that 63% of the southern floodplain forest (bottomland hardwoods) in the lower Mississippi River Valley (Louisiana, Mississippi, and Arkansas) has been replaced primarily by cotton and soybean crops. Degradation of wildlife habitat in the form of floral compositional changes and plant cover loss has been a major result of this trend (Harris et aI. 1984). In an effort to mitigate losses in bottomland acreage and concomitant losses in waterfowl habitat, many public land managers have resorted to GTR management (Fredrickson 1980).
Bioremediation Demonstration Unit at Weed, California
Year: Authors: Pope D.F., McGinnis G.D., Borazjani H., Strobel D., Wagner J., McFarland L.K., Hendrix F., Hannigan M.
As part of a comprehensive site remediation plan. land treatment of the pentachlorophenol and creosote contaminated soils was considered as a treatment alternative. This study was conducted to determine the feasibility of using land treatment on these soils. The study consists of three phases: Phase 1: laboratory studies of microbial degradation of pentachlorophenol and creosote in contaminated soils; Phase 2: a field demonstration study; and Phase 3: a full-scale land treatment demonstration facility. Phases 1 and 2 have been completed and the results are reported here.
A New State Geologic Map for Mississippi: A Tool for Updating Nomenclature and Definitions of the State’s Aquifers and Aquitards
Year: Authors: Dockery, III D.T.
The delineation of Mississippi’s aquifers and aquitards can only be as accurate as surface geologic maps and shallow subsurface cross sections allow. Insufficient surface and near-surface geologic data can result in erroneous ground-water models. In such cases, the computer adage "garbage in, garbage out" well applies. Detailed county geologic maps are available for only a half of Mississippi’s 82 counties, and some of the older county maps are in need of revision. The state geologic map is often used for areas where a county geologic bulletin is not available. This map, published in 1969, is only a minor revision of a 1945 edition and is itself in need of revision. Four major problem areas of the 1969 map need to be reexamined and remapped. These include: (1) the Nalheola outcrop belt, (2) subdivision of the Wilcox Group into formations, (3) the Winona-Kosciusko sequence in northwestern Mississippi, and (4) the Neogene (Miocene-Pliocene) sequence in southern Mississippi. Resolution of each of these problem areas will provide a much improved framework for the resolution of aquifers and for ground-water models.
Water Use in Rice, 1990
Year: Authors: Pennington K., Rodrigue P.
Knowing how much water it takes to produce a rice crop in the Mississippi Delta is important for two main reasons. First, any attempt at regulation of water use can only be effective if the regulating agencies have a good estimate of how much water the farmer needs to produce the crop with a "reasonable" level of management. Second, the need for conservation makes it imperative that the farmer be provided with a ’workable" amount of water to aim for when he is making both short and long term irrigation water management decisions. The key words "reasonable" and "workable" are important. Farming is a business. A farmer required to use methods that are so costly that they don’t allow for a reasonable profit, or asked to achieve a water use level that is so low as to be unworkable, will not be in business long. The demonstrations reported here were undertaken to find out how four different Delta farmers used their water to produce a rice crop. Our four fields were chosen on the basis of farmer cooperation, ease of well metering, and the ability to measure runoff. This was not a scientific study basad on random sampling or having controls. The farmers were volunteers who all use some water conservation techniques.
Comprehensive Study of the East Fork of the Tombigee Resource Issues by the Corps of Engineers and Soil Conservation Services
Year: Authors: Eubanks M.J., Keeter F.
The Corps, in coordination with the SCS, U.S. Fish and Wildlife Service (FWS), Mississippi Department of Wildlife, Fisheries, and Parks (MDWFP), and Tombigbee River Valley Water Management District (TRVWMD), initiated the East Fork Basin Study in March 1989, to address the identified resource problems in a systematic manner. Since this component was initiated late in the study process, the East Fork study can only be evaluated at a preliminary investigation level of detail. A task force, with representatives from the above agencies, was established to facilitate the conduct and coordination of the study.
Expectation of Maximum Daily Rainfall for the Central Climatic Region in Mississippi
Year: Authors: Nissan E.
This paper uses the same data employed by McGregor et al. for the North Central Climatic Region to reinforce and expand the theme of their work. The methodology adopted is based on the theory of extremes using the largest value of rainfall amount that occurred in a given month. Therefore. during a particular month there is only one measure which describes such a maximum even though there may be many days of the same record.
Computer Methods for Evaluating Wellhead Protection Areas
Year: Authors: Mallory M.J.
The 440 shallow, public water-suppiy wells are located in a variety of geologic settings ranging from interbedded lenticular, irregular sand and clay beds of Miocene age in the southem part of the State to fractured or jointed limestones of Paleozoic age in the northeastern part. One way of preventing contaminated groundwater from entering wells and springs is by establishing areas of protection around them. Since the establishment of such areas of protection necessarily restricts some uses of the land so designated, it is vital that the technical basis of the designation be scientifically valid, objective, and unambiguous.
The Effects of Record High Mean Monthly Streamflows in Selected Streams in North Mississippi in 1989
Year: Authors: Long L.
Flooding problems continue to plague the agricultural sectors in many par1s of the state even though numerous flood control projects have been installed. This paper analyzes the effects of the record high mean monthly streamflows experienced in selected streams in northern Mississippi during May through July 1989, due to the excessive rainfall occurring during this period. The streams on which the data are submitted are: Big Sunflower River; Coldwater Tallahatchie Rivers in the Delta area; and Big Black River.
Improving Estimates of Low-Flow Characteristics for Streamflow Stations Affected by Climatic Cycles
Year: Authors: Telis P.A.
This paper presents techniques for adjusting low-flow characteristics computed for annual low-flow data affected by climatic cycles. The development of these techniques involved the analysis of low-flow data for more than 100 streamflow stations on natural and unregulated streams in Mississippi and adjacent States.
Can the United States Afford Biomonitoring?
Year: Authors: Jones L.F.
Water pollution control efforts in the United States historically have been focused on establishing limits on the quantities of pollutants that may be discharged into surface waters by industries and municipalities. Discharge of pollutants is prohibited unless a permit is obtained under the National Pollutant Discharge Elimination System (NPDES)’, which is administered by the states with U.S. Environmental Protection Agency (EPA) guidance and oversight. The permit specifies the allowable effluent limits and the requirements for monitoring, recording, and reporting. In the past, the allowable effluent limits were based on Best Available Technology Economically Achievable (BAT) on secondary treatment, or on other technology-based criteria.
Substituting Climate for Groundwater in Aquaculture: The Potential for Conservation in the Southeastern United States
Year: Authors: Wax C.L., Pote J.W.
Locations were chosen to evaluate the effectiveness of the sclheme throughout the region by taking into account the east-west precipitation gradient and the south-north change from maritime to continental characteristics. This document addresses water use in aquaculture by reviewing sources and losses of water used in production and by developing climatological water budgets for ponds under differing climatic conditions in the region.
Water-use data collection program in Mississippi
Year: Authors: Callahan J.A., Barber N.L.
Information on water use is an important part of both technically- and managerially-oriented hydrologic studies. These studies often require current and long-term water-use data to assess the effect that human activities may be having on the water resources of an area. The data need to be accurate and consistent, and many of studies, such as those involving ground-water models, require that the data be site specific. During 1973, in recognition of the need for accurate, consistent, site-specific information on water use, the U.S. Geological Survey began the Mississippi Water-Use Program in cooperation with the Mississippi State Board of Water Commissioners (now the Mississippi Bureau of Land and Water Resources). During 1978, the U.S. Geological Survey initiated the National Water-Use Program to establish a nationwide water-use data base. The National program has goals similar to the State program: to collect, store, and disseminate consistent and accurate water-use data.
Furrow irrigation infiltration and evaluation
Year: Authors: Chism J.D., Rodrigue P.B.
The most important factor to consider in furrow irrigation is the ability of the soil to absorb irrigation water. The rate and the amount of water the soil will absorb is important in designing irrigation systems. Through "Operation Fuel" the SCS received a flowing furrow infiltrometer from the Mississippi Soil and Water Commission to help develop information about how different soils respond to furrow irrigation methods.
Suitability criteria for assessment of instream flow needs of fish
Year: Authors: Crance J.H.
My objectives here are: (a) to present an overview of the need, development, and use of stream habitat suitability criteria, and the use of these criteria for the assessment of instream flow needs; (b) to give a status report on the plan of the National Ecology Research Center (NERC) for expansion of instream flow research in the Southeast; and (c) to discuss the relevancy of the research to river corridor management.
A summary of the 1986 amendments to the Safe Drinking Water Act
Year: Authors: Crum W.B.
The Safe Drinking Water Act (SDWA) of 1974 includes legislation which gives the Environmental Protection Agency (EPA) ultimate authority over all public water supplies. EPA’s Office of Drinking Water manages the Public Water System Supervision Program, one of two national programs mandated by the SDWA. The SDWA requires EPA to develop National Primary Drinking Water Regulations for contaminants which may have adverse effects on human health. In addition, the SDWA requires EPA to monitor and enforce the Primary Drinking Water Regulations in order that drinking water supplies comply with maximum contaminant levels (MCls) .
Channel stability of selected streams in northern Mississippi
Year: Authors: Wilson K.V., Turnipseed D.P.
Many of the alluvial streams in Mississippi have been modified by such engineering practices as straightening, dredging, clearing, snagging, and dam construction to help alleviate flooding problems. Channel adjustments resulting from these types of modifications have been shown to result in channel and bank instability and, in some cases, to contribute to bridge failure. In Mississippi channels, widening in excess of 2 to 3 times the premodified width and degradation of as much as 19 feet have been documented by Wilson (1979). Alluvial channels are dynamic and adjust naturally to altered conditions , such as changes in base level or climate . The rate at which these channels adjust is related to the magnitude of the discharge and the channel gradient.
Groundwater sensitivity modeling using GIS technology
Year: Authors: Curtis P.A.
Protection of groundwater resources in Mississippi is administered by the Bureau of Pollution Control of the MS Department of Natural Resources (DNR) through the development of a groundwater protection strategy. The groundwater protection strategy’s long-term objective is to develop and administer the regulatory activities necessary to protect the state’s groundwater resources. Groundwater classification, quality standards, monitoring, planning and interagency coordination are several issues which are addressed in the strategy to help protect groundwater resources. The Bureau of Pollution Control of DNR contracted with the Mississippi Automated Resource Information System (MARIS) Technical Center to provide technical services using the MARIS geographic information system (GIS) to model groundwater sensitivity by determining potential contamination sites within one mile of public water supply wells. This model would identify potentially vulnerable water wells and help the Bureau of Pollution Control establish priority areas for future water quality investigations.
Water quality management for pH control
Year: Authors: Deliman P.N., Pote J.W., Cathcart T.P.
In intensive aquaculture, ’high-density algal blooms can cause marked fluctuations in pH. As the bloom undergoes photosynthesis, the carbon dioxide concentration undergoes a diurnal cycle mirroring that of the dissolved oxygen. The relationship between photosynthesis and pH has been well documented (Tucker and Boyd, 1985). In some waters. the resulting evening pH readings have been observed at levels as high as 12.0. well into the lethal range for many species. Certain waters have been implicated as having a low buffering capacity and hence an increased probability of mortality due to high pH (Boyd. 1982; Durborow, 1986).
Evaluation of instream flow requirements of fishes in the Ozark and Ouachita National Forests, Arkansas
Year: Authors: Ebert D.J., Filipek S.P., Dillard J.R.
The Clean Water Act of 1972 (PL 92-500) had a goal of assuring the Nation’s waters were "fishable and swimmable". Investigators soon learned that even minimal effects of land usage in a drainage basin could dramatically change water quality and flow in streams. The western uruted States has long experienc.ed water shortages due to low annual precipitation, increasing populations, and intensive agricultural and livestock grazing practices. As a result, numerous instream methodologies have been developed to assist in prioritizing water usage (Hutchins 1977; Orth 1980; Orth and Maughan 1980, 1981 , 1982; Stalnaker and Arnette 1976; Sweetman 1980; Tennant 1975). Bayha (1976) after summarizing the nationwide water problems in the 1970’s advised the eastern states to "get ahead" of the instream flow problem through plan formulation and investigation. Ten years later we are still attempting to formulate plans. Is it too late? Instream flow requirements have been defined by the Bureau of Land Management (1979) as "the quantity of water needed to maintain the existing and planned inplace uses of water in or along a stream channel or other water body and to maintain the natural character of the aquatic system and its dependent systems". Aquatic and riparian ecosystems and stream physical features were the dependent systems postulated by the BLM (1979). Stream physical features included channel, stream bed, flood plain, and flow pattern. Potential stream uses included human consumption, groundwater recharge, livestock watering, agricultural irrigation, recreation, and preservation of fish and wildlife. Judy and co-workers (Judy et al. 1984) reported that in a normal year 69% of the nation’s water courses had water available the entire year for fish requirements (breeding, spawning, foraging, and maintenance); 14% were not usable by fish during a portion of the year because of low or no flow; and 17% were used primarily in spring and summer. They mentioned that water quality problems affected fish in 68% of the nation’s waters. Forty-one percent of perennial waters were adversely affected. Major water quality problems included below optimum flows (32%), occasional low flows (23%), and excessive flow fluctuation (17%). One half of the waters were adversely affected by natural low flow conditions. Agricultural diversions adversely affected 14% of all waters. Stalnaker (1981 ) encouraged fishery and water quality agencies to protect instream resources by aggressively pursuing the establishment of stream flow standards as a parallel effort to water quality standards under the Clean Water Act of 1972. He reasoned that stream habitat is very dynamic, changing with the season and the annual water yield. Therefore, alternation of the stream flow not only alters habitat conditions, but may also change the order of relative abundance of fish species. This dynamic nature of the fishery ruled out use of historic low flows as a realistic minimum flow. Historic low flows as a minimum flow ignores the long-term recovery of a fishery that must occur after a severe drought. The establishment of historic low flows as allowable minimum levels would reduce the fishery to perpetual worst case conditions. Various instream flow methodologies have been developed to quantify stream flow standards. These plans made it possible to satisfy all water uses during some years, while in other years, certain water uses went unsatisfied. Past management schemes relying on impoundment and manipulation of streams have been only marginally effective in resolving this problem (Sweetman 1980). In Arkansas, only a few streams are completely unaffected by water development. These effects have been slight in some areas, while in others, streams have shown little similarity to natural flows (Hines 1975).
Analysis of 1987 flood of West Memphis, Arkansas
Year: Authors: Kung H., Richardson J.R.
The flooding that occurred in West Memphis, Arkansas , was an unusual phenomenon due to its magnitude and extent. Some places flooded beyond the 500-year flood boundary . The heavy damage and destruction encountered during this flood could have been reduced if proper and better executed measures had been implemented. On December 26, 1987, Governor Clinton of Arkansas declared a state of emergency and requested a federal disaster declaration. On December 31, the President of the United States declared Arkansas a major disaster area and made Crittenden County eligible for individual assistance programs.(1 ) The reason for these declarations was a four-day heavy-rain event in extreme Eastern Arkansas. In many places this flood affected more areas than the 500-year flood plain boundary as defined by Federal Emergency Management Agency (FEMA). The focus of this paper is the nature and causes of this flood and possible ways to reduce future flooding problems .
Regional skew coefficients for flood-frequency analysis of Mississippi streams
Year: Authors: Landers M.N.
Analyses of annual peak-flow records provide the empirical basis for estimating flood frequency. Statistical methods of analysis are well suited to the random nature of annual flooding. Statistical methods may be used to estimate flood frequency from a sample of recorded annual peak flows using the assumption that the recorded sample represents the population of all the recorded and unrecorded annual peak flows at that stream site. The Pearson type III distribution has been recommended as the appropriate probability distribution for log-transformed annual peak-flow data by the Interagency Advisory Committee on Water Data (IACWD, 1982). The Pearson type III distribution requires estimates of the population mean, variance, and skew.
1988 Rice water management study
Year: Authors: Rodrigue P.B., Chism J.D.
In 1988 the Soil Conservation Service (SCS) Water Management (WM) team monitored several fields of local cooperators. The objective was to apply water conservation practices on two of the fields to determine the value of the practices for water conservation
Preliminary steady-state simulation of ground-water flow in Hinds, Madison, and Rankin Counties, Central Mississippi
Year: Authors: Spencer J.R.
The purpose of this investigation is to better understand the ground-water flow in and around the Jackson Metropolitan area. Results from a ground-water flow model of the area will be used to determine the effects of future development on the flow system and ground-water resources of the area. The purpose of this preliminary report is to describe the regional geohydrologic framework and ground-water flow in the aquifers present in the three-county area in central Mississippi. The results of this six layer coarse-grid multi-state flow model will be utilized to determine the areal extent, aquifer characteristics, and layering scheme for a fine-grid ground-water flow management model of the three-countyarea.
Water resources management plan, Jackson County, Mississippi
Year: Authors: Waggoner J.A., Williford C.H.
The development of an area-wide water resources management plan is a dynamic process involving consideration of many complex issues. The initial step in formulation of the Water Resources Management Plan for Jackson County involved preparation of a Water Resources Evaluation. The following paper is a narrative summary of the Water Resources Evaluation report and related efforts spanning the years 1985 through 1987, and represents a compilation of the conclusions reached at that time. Due to the dynamic nature of the planning process and ever-changing socioeconomic conditions, the findings and recommendations noted herein may not reflect the current status of the various program elements.
Water filtration plants--Will the status quo do for the future?
Year: Authors: Walters J.V., deGraffenried J.B., John P.C.
High-rate filtration of public water supplies is becoming an attractive treatment technique because its smaller space requirements allow lower capital cost, and attendant coagulant dosages and sludge production result in lower operating costs. From the reports of research and operation of the process, there is widespread evidence that high-rate filtration is a treatment option worth your considering when you are planning to increase an existing plant’s capacity or designing a new facility.
Zeolite ammonia removal from catfish pond waters
Year: Authors: Williford Jr. C.W., Quiros M., Reynolds W.R.
The research objectives included first determining the ammonia uptake characteristics of clinoptilolite using model solutions and pond waters. Samples of clinoptilolite were obtained from various localities within the United States including some in Alabama and Mississippi. The primary characteristics investigated included dynamic ion exchange, total exchange capacity, and regeneration. The second objective included gathering of various design control data. These included pressure drop, ammonia capacity, and the required frequency of regeneration for the components of a zeolite (clinoptilolite) ammonia removal system. The final objective was the integration of components into a small scale ammonia removal system and the testing of this system.
U.S. Geological Survey atmospheric-precipitation monitoring in Mississippi, 1982-87
Year: Authors: Bednar G.A.
Atmospheric precipitation has become the focus ot attention in Mississippi with the realization that nitrogen and sultur compounds in the atmosphere contribute to acidic precipitation that can cause damage to terrestrial and aquatic ecosystems. Concern about the chemical quality of atmospheric deposition has caused State and Federai agencies to establish data-collection sites to monitor atmospheric-precipitation quality in Mississippi. Precipitation-quaiity data have been collected systematically by the U.S. Geological Survey as part of a cooperative program with the Mississippi Bureau of Pollution Control. Monitoring efforts began in 1982 in the southern part of the State at Janice and at the John C. Stennis Space Center (formerly the National Space Technology Laboratory) near Bay St. Louis. The operation of a third cooperative-program station began in 1986 at Rosetta. In 1982, the National Acid Precipitation Assessment Program (NAPAP) was established to provide research, monitoring, and assessment activities. Stations at Clinton and Coffeeville, operated by the U.S. Geological Survey, were established in 1984 tor the National Atmospheric Deposition Program and National Trends Network (NADP/NTN), an integral part of NAPAP. 58 Monitor-siting criteria and operational procedures for the five U.S. Geological Survey stations are the same as that for other NADP/NTN stations operated by the National Oceanic and Atmospheric Administration at Meridian since 1980, with a colocated station at New1on, and the U.S. Environmental Protection Agency Network station operated by the Mississippi Bureau of Pollution Control at Oxford since 1982. The seven stations provide the framework for a statewide monitoring network that will provide the data required for future atmospheric-precipitation quality assessments of long-term trends and possible
An assessment of buffalo fisheries resources in a Mississippi stream three decades after channelization
Year: Authors: Jackson D.C., Jackson J.R.
Fisheries resources associated with the larger floodplain rivers in the Yazoo River Basin of western Mississippi are an integral component of the reqion’s cuitural and natural heritage. During winter and spring elevated flow regimes on these systems, artisanal and subsistence fishermen in the region have traditionally directed much of their effort toward buffalos, Ictiobus spp. Catostomidae). There is considerable evidence suggesting that such seasonal patterns of natural resources exploitation continue to be important components of rural culture even in technologically developed regions of North Arnerica. With few exceptions, streams in the Yazoo River basin of western Mississippi have been channelized. As a result of these federal flood control projects it has been estimated that fewer than 20% of the stream reaches in the basin were capable of supporting a fishery of any kind with even fewer reaches supporting sport fisheries. Although recovery processes for streams impacted by channelization can be slow, this does not preclude the possibility of fisheries resources in such systems recovering to levels capable of providing benefits to society with in a reasonable period of time. In this regard we were interested in determining the population structure of buffalo stocks and their status as exploitable resources in the Yalobusha River (Figure 1), one of the principal tributaries of the Yazoo River, three decades after its original channelization. Catch rates of commercial fishes from the Yaiobusna River have been reported to be equal to or to exceed those of other major streams in Mississippi and that collect ively, buffalo were the most abundant large fishes in the system.
Crop water use
Year: Authors: Pennington D.A., Pringle L., Tupper G., Wolf R., Hamill J.
Water use in the Mississippi Delta is dominated by agricultural use. Approximately 85% of all water is used for the flooding of rice, filling of catfish ponds, or irrigation of cotton and soybeans. That water must be used efficiently to ensure the long term availability of water to agriculture. This paper will briefly review some of the research activities completed or underway by scientists of the Mississippi Agricultural and Forestry Experiment Station (MAFES) to improve our understanding of water resources in the region and efficient use of water.
Ground water extraction trends in Forest and Lamar counties, Mississippi
Year: Authors: Patrick D.M., Zhao S.
The primary purpose of this research is to document and describe, using computer graphics methods, the local and regional historical drawdown of piezometric surtaces in Forrest and Lamar Counties, Mississippi. The secondary purpose was to further our understanding of the geologic framework of the aquifers in this region. These studies were undertaken because of increased urbanization and industrialization in this region of south Mississippi, and the evidence that ground-water levels in this area are declining (Wasson, 1986). The studies presented here are a part of a more comprehensive investigation dealing with the development of predictive (groundwater) models for the aquifers of Forrest, Lamar, and Jones Counties.
Plasmid profile analysis of fecal coliforms isolated from natural waters
Year: Authors: Evans J.A., D'mello N.P., Hamilton K.K., Taylor R.D.
The main goal of our work was to determine if plasmid profile analysis could be used to assess the bacteriological quality of water.
A systems approach to water quality management during drought periods in the Cumberland River Basin
Year: Authors: Hayes D.F.
Operating complex water resource systems like interdependent multi-objective hydropower reservoirs to satisfy competing objectives is difficult. Most reservoirs are operated according to a guide curve which provides monthly headwater targets that meet reservoir and basin objectives under normal conditions. Guide curves, however, lack the sophistication to vary the headwater targets based upon changing conditions and priorities. Extreme conditions such as a drought exacerbate the problem, especiaiiy when combined with natural reservoir stratification and resulting water quality implications. This paper presents a method to determine alternative operating strategies under stratification and drought conditions. The Cumberland River basin in northern Tennessee and southern Kentucky is used as an example.
Apparent changes in the potentiometric surfaces of cretaceous and paleozoic aquifers in Northeastern Mississippi, 1955-1988
Year: Authors: Hoffmann J.H., Phillips P.A.
A series of potentiometric maps were constructed based upon selected water level data from the Coffee Sand, Eutaw-McShan, Gordo, and Paleozoic aquifers in northeastem Mississippi. These aquifers constitute important sources of fresh water in this region and have been subjected to progressive stress for many years due to an increasing demand for public and industrial water supplies. The response of these aquifer systems to the stresses caused by these withdrawals of water has been a general long-term decline in regional water levels and a more dramatic decline in regional water levels and a more dramatic decline near centers of greater pumpage. This work represents the first element in the development of a layered ground-water flow model of the aquifer systems which underlie this part of Mississippi. Development of these aquifers by man has been in progress for more than a century. Artesian wells were reportedly drilled in northeastern Mississippi prior to 1850 and wells as deep as 1,000 feet were drilled in Chickasaw and Clay counties by 1860. After 1900, pumpage at some locations became significant. Since about 1945, many more wells have been drilled and ground-water withdrawals in northeastern Mississippi have contlnually increased.
Contamination of water supplies by metals from copper pipe and lead-solder
Year: Authors: Allen K.
A major concern in recent years has been the effect of water characteristics on the dissolution of metal ions from copper pipes with lead based solder. A study was conducted to determine ij characteristics such as water corrosivity, alkalinity, pH, chlorine disinfection, chloride concentration, and copper concentration will effect the final concentration of lead in first-draw samples. Two phases of research were conducted to accomplish these objectives: a pilot study employing three piping networks fabricated of copper with lead soldered joints placed at three well sites, and a field study of tap water from homes throughout the state of Mississippi. The field study showed that all samples which exceeded the maximum contaminant level (mel) for lead at 0.05 mgJl were taken from water supplies which were either low pH, low alkalinity, or high chloride waters. Also, most of these samples were taken from homes with plumbing less that two years old and almost all of the samples showing any lead content were from homes with plumbing less than five years old. The pilot study indicated that high iron content in the water can prohibit lead leaching through the formation of a passivating film. Also, high chloride content appeared to enhance lead leaching. It was noted that most waters appear to promote lead dissolution even when water characteristics are not considered extremely aggressive. In both studies, the simple procedure of allowing the water to flush for one minute virtually eliminated the lead from the samples. New EPA regulations include a ban on the use of lead-based solder in potable water plumbing. However, there are major questions as to the enforceability of this ban especially in states with no plumbing code or licensure procedure. Proposed EPA regulations include new standards for pH and alkalinity in finished water. The effect of these proposals on small water systems will be a major concern in the future. Also, discussion is warranted on the effectiveness of this treatment in reducing lead content.
Fish and Wildlife Concerns in Mississippi’s Water Management with Particular Reference to the Upper Tombigee River Basin
Year: Authors: Goldman L.E.
I would like to address the issue of how fish and wildlife resources relate to water management in Mississippi by examining several questions. What is the status of these water related resources? What have been the historical concerns associated with Mississippi’s water resources? What new concerns are developing related to these important natural resources of the state? What needs to be done to sustain these resources? Through examination of an emerging water conflict in the Upper Tombigbee Basin, I would like to demonstrate one possible approach toward answering some of these problems.
Water Resources Planning in Mississippi: A Status Report
Year: Authors: Palmer J.
In the field of water resources regulation and management, "planning" embraces a very wide spectrum of specific issues related to the availability, condition, use, and protection of the surface water and ground water that people - and all our sundry activities depend upon. While the issues touched in the planning process are diverse and numerous, there ultimately are two basic questions which we in Mississippi must face in responding to the legislative mandate to prepare a Statewide Water Resources Management Plan: (1) what will this plan address; and (2) who and how will the plan be produced? For perspective, we should take a brief glimpse of fairly recent history.
Summary of Geohydrology and Simulated Effects of Ground-Water Withdrawals on the Miocene Aquifer System in the Mississippi Gulf Coast Area
Year: Authors: Watson B.E.
The objective of this investigation was to gain an understanding of the ground-water system along the Gulf Coast (fig. 1)-a task made more difficult by the complex nature of the geology. The Miocene and Pliocene sediments that make up the Miocene aquifer system consist of interbedded and lenticular sands and clays. Thesa sediments crop out in southern Mississippi and dip to the south and southwest. They do not fit the concept of layered geology but do exhibit large vertical variations in head and locally respond to stresses as separate aquifers. An analysis of wef! data along the Gulf Coast indicated that an aquifer system with eight layers having surfaces based primarily on the dip", slope of the base of the mappable Miocene deposits would best represent the vertical heads in the Miocene aquifer system.
Agricultural Water Management Panel Discussion
Year: Authors: Hutson B.
In the Mississippi Delta, increased agricultural demand for water has placed the Alluvial aquifer under severe stress. The eighteen Delta and part-Delta counties that make up the 7,000 square-mile Alluvial plain are the seat of ninety-eight percent of Mississippi’s irrigation and aquaculture needs. The demands account for a water use in excess of 1.1 billion gallons per day, according to the Mississippi Bureau of Land and Water Resources. The Alluvial aquifer is dropping at a rate of 1.5 feet per year, faster than nature can replenish it. This panel discussion was an infannal presentation by the Delta farmers who have experimented with various methods to reduce their dependence on ground supplies. Most of the discussion centered on landlonning, which has substantially reduced the amount of water they need to grow rice and soybeans. Closely allied with landforming is more intensive management of applying water to the land. Also discussed were the relifting of surface water and the use of stream sources. In addition to water conservation, the economic benefit of reduced pumping costs was a major factor in long-range planning for these farming operations.
Producing More and Better Water at Minimum Cost
Year: Authors: Singley J.E.
Case histories of water treatment plant quantity uprating and quality upgrading will be presented. The plant sizes will range from 2 to 600 MGD. The plant types will vary from clarification to softening and from conventional horizontal flow to upflow clarifiers. The cases cited will not be based upon the obvious uprating of filters alone but upon chemical and physical process marges that have produced better quality at the higher rates. The economic effects will be shown.
Use of Water Hyacinths to Upgrade Wastewater Treatment Plant Effluents
Year: Authors: McAnally A.S., Benefield L.D.
One of the primary differences between conventional and aquatic treatment systems is that in the conventional system wastewater is treated rapidly in a highly managed environment, but in the aquatic system treatment is relatively slow in an essentially unmanaged environment. Since the primary impetus for this research is to investigate the feasibility of employing water hyacinths to enhance previously treated wastewater, possibly by conventional means, the discussion will be mainly devoted to the treatment of wastewater which is of approximately secondary effluent quality. The parameters of concern in wastewater treatment include suspended solids, organic compounds, pathogens, nutrients, heavy metals and dissolved inorganic salts.
Application of the Thornthwaite Budget to the Hydrology of Three Tennessee Watersheds
Year: Authors: Kung H., Knack M.E.
Water budget analysis is a useful method for the study of water surplus and runoff in a drainage basin. The purpose of this paper is to apply the Thornthwaite water budget method to three selected rural Tennessee watersheds. The watersheds are the Loosahatchie River in West Tennessee; the East Fork of Stone River in Middle Tennessee, and the Little River in East Tennessee. The calculated runoff from the three watersheds, using Thornthwaite water budget methods, are compared with the measured runoff data to evaluate the validity of the water budget method and to determine the possible effects of watershed characteristics on total amount of surface runoff. The average monthly calculated runoff for the East Fork of Stone River for the 14-year period, 1972-1985, was very dose to the average monthly measured runoff. The Little River in East Tennessee produced more runoff than calculated, while the Loosahatehie River in West Tennessee produced less runoff. The discrepancy for the Little River is due to the fact that the watershed lies in an area of greatly variable elevation and precipitation. There is no immediate explanation for the Loosahatchie’s discrepancy. Water budget procedure does provide a useful means for understanding the basin hydrology in this study. Water budget analysis is a useful method for the study of water surplus and runoff in a drainage basin. The purpose of this paper is to apply "’e Thom"’waite water budget me"’od to "’_ selected rural Tennessee watersheds. The watersheds are the Loosahatchie River in West Tennessee; the East Fork of Stone River in Middle Tennessee: and the Uttle River in East Tennessee. The calculated runoff from the three watersheds, using Thornthwaite water budget methods, are compared with the measured runoff data to evaluate the validity of the water budget method and to determine the possible effects of watershed charaderistics on total amount of surface runoff. The average monthly calculated runoff for the East Fork of Stone River for the 14-year period. 1972-1985, was very dose to the average monthly measured runoff. The Uttie River in East Tennessee produced more runoff than calculated, while the Loosahatehie River in West Tennessee produced less runoff. The 56 discrepancy for the Little River is due to the fact that the watershed lies in an area of greatly variable elevation and precipitation. There is no immediate explanation for the Loosahatchie’s dscrepancy. Watar budget procedure does provide a useful means for understanding the basin hydrology in this study.
The Formation of a Water Management District
Year: Authors: Harrison W.
In 1978, Northwest Mississippi leaders recognized that the Delta’s groundwater resources for agricultural and industrial purposes needed to be monitored to determine the relationship between the level of recharge and drawdown on our alluvial aquifer. The alluvial aquifer is our shallow aquifer unique to the Delta At that time, rice acreage was increasing, catfish pond acreage was increasing, and irrigation of row crops was becoming more widespread. A request was made by Farm Bureau and Detta Council to the Department of Natural Resources and the U.S. Geological Survey for a comprehensive study to be conducted throughout the Delta on this alluvial aquifer.
Rural Water Association Circuit Rider Program
Year: Authors: Shows T.
The Mississippi Rural Water Association sponsors a program for helping rural water systems and small towns manager their water and operate their systems more efficiently. The association actively employes a program manager and a circuit rider to present seminars, training sessions, and personal help concerning water management. The circuit rider program offers training in seminars and training sessions and a direct one-on-one program of effective and efficient water management and know-how to rural Mississippians.
Sedimentation Modeling in Streams with Obstructions
Year: Authors: Wang S.Y.
For maximum benefits from water resources in rivers and streams, it has been necessary to build hydraulic structures in them for a variety of purposes. Some of these are navigation, flood control, irrigation, environmental protection, and water supply. The introduction of man-made obstructions (from the river flow point 01 view) into the streams and rivers can cause significant changes in sedimentation processes. Not only are local scours and deposited dunes found in the vicinity of these obstructions, but the bed form, bank erosion and water quality in regions farther afield are also affected. At a time when society is greatly concemed about both environment and the quality of the water supply, it is very important to determine the impact to these obstructions before construction takes place.
Comparison of Extreme 1-Day Amounts of Rainfall for Coastal and North Central Climatic Regions of Mississippi
Year: Authors: McGregor K.C., Muller R.A., Murphee, Jr. C.E.
Comparison of the frequency and magnitudes of 1- day excessive events in the North Central and Coastal Regions provide information about the extremes expected in rainfall patterns and amounts in Mississippi. In this study, daily rainfall events of three or more inches were tabulated by months for selected stations within the North Central and Coastal Climatic Regions of Mississippi. Comparisons of events for the two regions were made for the 1951-1980 standard period and by decades.
Muddy Creek Grade Control Structures, Muddy Creek, Mississippi and Tennessee
Year: Authors: Tate, Jr. C.H.
Muddy Creek is located in extreme north Mississippi and south Tennessee and flows generally north from Ripley, Miss., to the Hatchie River just north of the Mississippi-Tennessee State line. Between September 1976 and September 1983, the Soil Conservation Service (SCS) modified the Muddy Creek system by constructing a trapezoidal channel with 12 riprap grade control structures spaced along the main channel. The fU’St four structures (structure No. 1 being the farthest downstream) and connecting channel were constructed between September 1976 and February 1980, using the procedures in SCS’s ~9, "Hydraulic Design of Riprap Gradient Control Structures" (reference 1). Surveys of the structures during 1980 indicated that severe scour, up to 15 ft. deep, had occurred immediately downstream of several structures. Postulated as a cause for the scour was flow separation in the 1 on 4 exit flare which caused eddies to form along the side slopes resulting in flow concentrations in the channel. The remaining grade control structures were constructed with a 1 on 8 exit flare in an effort to improve exit flow conditions. Heavier riprap was placed at the downstream end of the prismatic section and the upstream portion of the exit flare. However, scour holes again formed immediately downstream of these structures. A model investigation was conducted to determine the flow conditions that were causing the observed scour and to develop modifications to the existing structures to minimize the scour conditions. Additionally, the model study was used to develop design modifications to prevent the flow conditions causing scour.
Stream Channel Erosion Contribution to Sediment Yields in Complext Watersheds
Year: Authors: Bowie A.J.
Streambank erosion, in itself, is an extremely complex subject from the point of view of its genesis, its effects, and its prevention. Whether or not erosion occurs depends upon the composition and condition ofthe soil composing the bank, and the erosive action of the stream. Why some banks erode and similar ones do not is not fully known. A number of variables are involved in the process and may exert their influence individually. More often, however, streambank, erosion is the result of a complex combination of variables, making it extremely difficult to understand, predict, and to treat. The problem of channel erosion is one for which there is pressing need for quantitative answers. Quantitative analysis and evaluation of data relative to channel erosion, and more especially streambank erosion, are very difficult, and in some cases, almost impossible to obtain. Research is continuing on the subject of both streambank and streambed erosion with increased emphasis on estimating erosion quantities, predicting the effects of erosion on channel characteristics, and identifying control factors.
Evaluation of the Disinfection Effectiveness of an Ozone Treatment Device for Individual Water Supply
Year: Authors: Iglar A.F., Okome B.E.
As a disinfectant, ozone has a number of advantages over other chemical agents. It does not increase the organic salt content of the water, it does not impart any taste or color, and it is a powerful disinfectant (Tbirumurthi, 1968). For such reasons, ozone has been used, especially in Europe, as a disinfectant of water, principally for municipal supplies. In the United States, ozone is not in common use, apparently chiefly because it produces little or no residual in the distribution system. However, it has been noted that ozone treatment is potentially adaptable to individual water supplies. Its advantages in this application include simplicity, effectiveness over a wide range of pH (Burris, 1977), and minimum need for consumable supplies, such as chlorine. The objective of this study was to determine the effectiveness of a particular compact ozonator, the "Sojo Model 243-INGL," based on levels of microorganisms prior to and after treatment. Tests were performed for heterotrophic plate count coliforms, and fecal coliforms. Three samples were studied from each of six water supplies.
Development of a Computerized Water Balance Program for the Eastern Arkansas Region Comprehensive Water Supply Study
Year: Authors: Martin W.D.
The Eastern Arkansas Region Comprehensive Study was a Reconnaissance level study authorized by the Congress for the purpose of determining the need and feasibility for improvements in the interest of flood control, water conservation and water supply for municipal. industrial and agricultural purpoees in a 24 county region of Eastern Arkansaa. A basic tool for analysis of the existing and future conditions of the area was to be the preparation of a water balance. Due to the time constraints placed on completion of the project, a computerized water balance program was developed to aid in meeting the schedule and to allow flexibility for determination of alternative future conditions. The development of this program is described herein. The final product was a FORTRAN 77 code about 500 lines in length. It was developed on a HARRIS 500 computer and utilized the HARRIS data base management system, INFO, to manipulate the input files.
Application of a Layered Groundwater Model to Critical Areas in Northeast Mississippi
Year: Authors: Zitta V.L., Pang T.K.
The objective of this study was the upgrading of a model of the Eutaw-McShan aquifer to simulate accurately the piezometric heads for the calibration period from 1978 to 1982. Emphasis was on the major pumping areas around West Point, Tupelo and Aberdeen-Amory.
Quantifying Water Surface Supplies
Year: Authors: Martin S.K.
This paper will present the methodology used in the "Eastern Arkansas Region Comprehensive Study" conducted by the U.S. Army Corps of Engineers, Memphis District, in which all water resources were identified and quantified for a water balance analysis. The study was undertaken to identify areas in which deficit water supplies occurred or were projected to occur, and to propose alternatives for alleviating the problems.
An Alterntive Basin Characteristic for Estimating Impervious Area and Urban Flood Frequency and its Potential Application in Mississippi
Year: Authors: Southard R.E.
This paper will briefly discuss methods of computing the urban basin characteristic, percentage of impervious area. An alternative basin characteristic termed percentage of developed area, which can be used to compute percentage of impervious area, is described and applied to basins in Mississippi. Statistical analyses indicate that percentage of developed area is applicable for use in estimating impervious area and is potentially useful in estimating the magnitude and frequency of floods in urban areas in Mississippi.
Miocene Groundwater Overdraft in Southern Mississippi
Year: Authors: Fenske P.R.
Miocene water level declines of approximately one foot or more per year have often been reported in the literature on Mlsaissippi water resources. This paper will present data relative to water level declines in the Miocene in the area of Tatum Dome, 9 miles west of Purvis. Mississippi. The main thrust will be to present data from holes currently monitored on Thtum Dome by the Environmental Protection Agency (EPA). These data will be presented along with historical measurements in the same area to show the water level declines over a period of approximately 25 years. The original holes were drilled and completed in the Miocene in the Tatum Dome area in support of an AEC (now DOE) project. These holes have never been used to any extent for water production and the closest significant production from the Miocene is probably at Purvis, 9 miles to the east, also in Lamar County. The purpose of this paper is to provide some conclusions and discussions of the implications of the water level declines noted.
USDA-Soil Conservation Service Irrigation Water Management Program in Mississippi
Year: Authors: Rodrigue P.B., Harris R.K.
To help Mississippi farmers use their water resources most efficiently, the USDA-Soil Conservation Service initiated an Irrigation Water Management program in the summer of 1985. An Irrigation Water Management (IWM) team consisting of an agronomist, soil scientist, and agricultural engineer has been charged with providing technical assistance to farmers in managing their irrigation water supplies. The initial thrust ofthe irrigation team has been directed toward evaluating the performance of existing center pivot irrigation systems for water and energy use efficiency and the intake characteristics of the soil under these systems. There are approximately 1000 center pivot systems in the delta. One center pivot system pumping 1200 gpm will pump 1-3/4 million gallons per day which is the equivalent to the water use of the town of Indianola2. The irrigation team is also responsible for updating the Mississippi irrigation guide with information on the intake capability of different soils under different cropping patterns. This report will briefly explain the 1986 test methods, accomplishments, and goals of the IWM team.
The Effect of the 1987 Drought on Streamflow in Selected Streams in Mississippi
Year: Authors: Long L.G., Clevenger C.E.
This paper analyzes the effects of the drought on streamflow by comparing 1986 mean stream discharges with mean stream discharges for the period of record at selected sites. Comparisons have been made of three watersheds in different geologic settings which exhibit distinctively different water-yielding characteristics. The three watersheds are the Bogue Chitto near Tylertown, Town Creek in Tupelo, and the Big Sunflower River at Sunflower.
Water Allocation: Benevolent Czar or Crystal Pitcher Approach
Year: Authors: Mack L.E., Peralta A.W.
Extensive allocation/permitting programs do not create another drop of water but do produce a costly flood of administrative paper work. Information sharing within local/substate water management districts (the crystal pitcher approach) allows both users and professional water managers to more clearly visualize the water resource and to make informed decisions regarding its use. The approach may be used in conjunction with various institutional arrangements, but requires legislative and/or judicial action for adoption in most states. including Arkansas. A brief generalized overview of the development of existing types of water law systems and their influence on the emergence of centralized regulatory water management is presented. A discussion of the benevolent czar and the crystal pitcher is followed by a short evaluation of the effectiveness of the different approaches.
The Effect of the 1986 Drought on the Mississippi River Alluvial Aquifer
Year: Authors: Spencer J.R., Ehret K.S.
The water-level declines experienced in the Delta over the past 10 years were greatly intensified by the record-setting drought during 1985-86. The drought conditions experienced in the winter and spring months combined with the tremendous demand placed on the aquifer for irrigation and aquaculture water resulted in the greatest yearly decline observed to date. The purpose of this study was to determine the effects of low precipitation, decreased runoff, and increased pumpage on the Mississippi River alluvial aquifer.
Moving Toward Alabama Legislation for Water Resources Management
Year: Authors: Warman J.C.
In recent months much attention has been focused at the national level on ground water problems, ground water management, and ground water protection. In August 1984, EPA released its Ground Water Protection Strategy (2). Overall, the Strategy was designed to rationalize and better use the many statutes EPA has for protecting ground water. Thus, it focused on achieving four broad objectives: to enhance state programs, to deal more effectively with ground water problems of major national concern, to create a policy framework for guiding EPA programs, and to strengthen EPA’s internal ground water organization. The states have the principal role in protecting ground water. This is mainly because oftheir historical and legal roles in land use, water allocation and public health protection, as well as the lack of overriding federal legislation. The federal government currently is responsible for controlling certain contaminants and activities affecting ground water, such as hazardous waste sites and pesticides. It also provides substantial research, information-gathering. technical and financial assistance to the states. While several federal agencies are involved to varying degrees with protecting ground water, the U.S. Environmental Protection Agency has the leading role in this area.
Saline Water Occurrence Within the Tertiary Sparta Sand and Cockfield Aquifers of Washington County, Mississippi
Year: Authors: Bockelmann D.J.
It is the intent of this report to provide sufficient information to define chloride and dissolved solids concentration levels in Washington County with respect to geography and depth within the two individual aquifer systems. In addition. a method utilizing geophysicsl electric logs to estimate ground-water quality will be discussed. It is hoped that this information will prove useful to water managers in Washington County in selecting future well sites and well depths and in obtaining consistent high quality drinking water.
Water Management District
Year: Authors: Harrison W.M., Morgan C.
The Mississippi Delta is endowed with some of the most abundant ground water resources to serve both agriculture, industry and municipal water supplies of any region in the world. In the last two decades agricultural and industrial technology has changed, creating increased demands on this natural resource. Rice acreage has dramatically increased, catfish farming has become a leading agricultural enterprise, and cotton and soybean farmers are relying more heavily on irrigation today. Even though research and technology have enabled agricultural use of the Delta’s water resources with a much greater emphasis on conservation, the future of American Agriculture is becoming more closely related to the availability of water than ever before. Industries that rely on a reliable source of quality ground water have also chosen the Delta as a site for locations and expansions because of the abundance of availability of this natural resource. In 1978 Delta Council recognized that the Delta’s ground water resources for agriculture and industrial purposes, needed to be monitored, to determine the relationship between the level of recharge and drawdown on our alluvial aquifer.
Simulation of the Flow System in the Shallow Aquifer, Dauphin Island, Alabama
Year: Authors: Kidd R.E., Mooty W.S.
The development of freshwater aquifers on Dauphin Island, Alabama, for industrial and domestic supplies is threatened by saltwater encroachment. At present, chloride, iron, and total dissolved solids concentrations in water at depths from 250 to 300 feet in municipal wells supplying the island exceed maximum contaminant levels recommended in National Secondary Drinking-Water Regulations (U.S. Environmental Protection Agency, 1982). The surficial aquifer is the only source of potable water with a chloride concentration below the maximum contaminant level recommended in the National Drinking-Water Regulations.
Water Allocation in Kentucky: Legal and Institutional Frameworks
Year: Authors: Lee V.D.
Water rights in Kentucky may be characterized as a complicated mixture of statutory and common law rights, which Richard Ausness reviewed in a 1977 Kentucky Law Journal article (’Water Use Permita in a Riparian State: Problems and Proposals/) 66 Kentucky Law Journal 191 (1977)). Despite some fundamental problems, however, superimposing statutory rights on older common law roles has served to make water rights available to more users than under common law exclusively.
On the Methodology of Modeling Sediment Transport in Water Resources Systems
Year: Authors: Wang S.Y.
Soil erosion and sedimentation activities have profound effects on water resources systems. Sediments are not only a major water pollutant by weight and volume, but also carriers and storage agents of agricultural, industrial and domestic wastes. To prevent the degradation of quality water resources, we need to have a better understanding of sediment transport phenomena and their effects on the water resources. Due to the complexity of sediment transport characteristics, it is difficult to investigate these characteristics analytically. Therefore. the methodologies applied to hydraulic and sedimentation research in the past were primarily empirical. These methodologies are also referred to as hydraulic modeling or physical modeling. As water resources systems became more and more complex, the application of physical modeling to investigate the sedimentation processes has become more and more costly in terms of funds and time. As a result, sedimentation researchers have been searching for alternative methodologies which are more cost-effective than those used in the past. Recently, the application of digital computers to hydraulic research has gained popularity. Not only can computers make physical modeling more efficient by automation of the data acquisition and analysis, as well as control of test conditions; but they can also reduce the number of tests required to complete a study by supplementing physical modeling with computational simulation.
Indicators of Downward Leakage from the Water-Table Aquifers to the Principle Artesian Aquifer at Memphis, Tennessee
Year: Authors: Parks W.S.
In order to better assess the potential for interaquifer exchange of ground water, the U. S. Geological Survey, in cooperation with the Tennessee Department of Health and Environment, Office of Water Management, and the City of Memphis, Memphis Light, Gas and Water Division (MLGW). initiated an investigation in 1984 to determine the potential for leakage among the principal aquifers in the Memphis area. This investigation consisted primarily of the following elements: 1. geologic information was compiled from geophysical logs, and maps were prepared to show the thickness of the confining beds and the aggregate thickness of clay beds within the confining beds; 2. temperature data were collected using geophysical methods to determine the normal geothermal gradient and deviations from the normal gradient; 3. ground-water level data were collected, and potentiometric maps and derivative head difference maps were prepared to show the potential for vertical movement of water; and 4. water samples were collected and analyzed for selected isotopes of carbon and hydrogen to determine the relative ages of the water.
Coordination: The Missing Element in Water-Resources Planning and Management
Year: Authors: Moffett T.B., Walters J.V.
Of the attributes essential to successful water-resources planning and management, "coordination" is undoubtedly one of the most important. In Alabama, where several agencies can be involved in similar aspects of the same program and where each agency can have many responsibilities, coordination is even more essential. Effective coordination signifies effective leadership, that programs have direction, and that the whole system is operating efficiently and effectively. Effective coordination also signifies that those in positions of leadership are aware of common problems and goals and that each agency assumes some of the responsibility necessary for solving these problems and for reaching specific goals. In this study, Alabama’s water-related agencies and their activities were examined both objectively and subjectively from a lengthy questionnaire. The authors were specifically interested in factors that had inhibited the implementation of an effective water-management plan. The results of this study indicate that some water-resources activities are coordinated. In all aspects of the State’s water-resources program, however, ineffective coordination of activities has prevented the agencies from formulating an effective water-management plan.
Hydrologic Effects of Forestry Practices in Mississippi
Year: Authors: Ursic S.J., Duffy P.D.
Of the many environmental concerns related to forestry, a prime consideration is how forests and forestry practices affect the disposition of precipitation and the quality of streamflow. This report discusses the hydrology of undisturbed forests and changes related to reforestation, species change, and harvesting.
Quality of Water and Nature of Contamination ofShallow Aquifers in the Gulf Coastal Plain of Louisiana and Mississippi
Year: Authors: Strickland D.J., Bednar G.A., Everett D.E., Fendick R.B.
The purpose of the reconnaissance study was to make a preliminary assessment of the ambient water quality and changes in chemical quality of water that occur in shallow aquifers as a result of three types ofland-use practices that are typical of the Gulf Coastal Plain. Emphasis was placed on obtaining data to determine the presence or absence of contaminants in shallow ground water.
Spatial Aspects of Weekly Precipitations Probabilities
Year: Authors: Wax C.L., Pote J.W.
The source of both surface water and ground water is precipitation. Although precipitation is generally included within the realm of meteorology, it has direct bearing on the only part of the hydrologic cycle with which man can interact. It should, therefore, be considered strongly in water resource management strategies. Mississippi is particularly well-supplied with water from the atmosphere and this climatological characteristic establishes the natw’e of the state’s water resource. With the exception of Louisiana, no other state in the union receives as much precipitation per square mile on an annual basis as Mississippi (2). During the past 30 years, the state has received an annual average of about 54 inches in the northern part of the state and 62 inches in the southern part of the state. The statewide annual average of 56 inches, if spread evenly over the state, would amount to approximately 142 million acre-feet of water delivered by the atmosphere to the state each year (3). However, this resource is not equally distributed in either time or space, so the real water situation in the various areas in the state is quite different; at times it is drastically different. Many aspects of water resource management could be enhanced by a better understanding of the temporal and spatial characteristics of precipitation in Mississippi. The temporal occurrence, timing, and amount of precipitation in Mississippi have been recently quantified and stated in probabilities for seven-day periods through the year (4). The probabilities were developed from the precipitation record from 1951-80 at 56 locations in the state using the incomplete gamma distribution. A description of the gamma distribution and its use in precipitation analyses is not included in this paper but is available in the referenced document (4). The probability information is used in this paper to produce maps to evaluate the spatial characteristics ofweekly precipitation statewide for selected periods during the year.
Policy Development for Greywater Treatment and Reuse
Year: Authors: Perry R., Iglar A.F.
Greywater includes household waste water, except that originating from toilets and garbage disposal units. Typical sources include kitchen sinks, dishwashers, bathtubs and showers, clothes washers, and others (Siegrist, 1977). One particular basis for interest in greywater treatment and reuse has been the potential to lessen the quantity of wastewater which actually requires disposal, for reasons such as alleviating overloading of disposal systems (Kane, 1981). The perception has been widespread that public health agencies have poorly developed guidelines for evaluating greywater treatment and reuse systems. This lack of guidelines is thought to explain the view that public health agencies are poorly receptive to greywater systems in the United States. The objective of this study was to analyze existing literature on greywater characteristics as well as treatment and reuse systems, in order to develop guidance for public health policy applicable to greywater treatment and reuse. The study was limited to small systems applicable to domestic sources of greywater. It was recognized from the earliest stages of study that available information might not be sufficient to support a fully developed public health policy. In this case, the study was intended to develop whatever preliminary policy guidance that could be supported.
Mississippi Automated Resource Information System (MARIS)
Year: Authors: Davis P., Belokon W.
A fundamental problem in the operation of an organization is the management of information. When referring to information management the dimension most commonly thought of is storage. Data management, however, includes not only the storage of data but also the gathering ofnew data, refinement of existing data, making users aware of data that are available, and providing access to existing information. As organization size increases, the problem of information management becomes more acute. The problem can be even more pronounced in state government where the entire organization is composed of relatively autonomous units with a wide diversity of responsibilities. Each entity is almost constantly collecting and synthesizing information, often in isolation from other entities. One group may be gathering data while another group might already have them on file. Two or more units may have very similar data requirements that could be addressed through one coordinated effort rather than each unit duplicating the other’s efforts. In an effort to minimize such problems in Mississippi state government, the Mississippi Automated Resource Information System (MARIS) was established. MARlS is intended to serve as a central point from which users can obtain data or be directed to sources of any existing data. The system focuses on natural resource related information and is available to all public and private organizations, but gives priority to Mississippi state agencies. MARIS has approached its mission through the: 1. compilation of a statewide catalog of natural resource data; 2. establishment of a statewide geographic information system with related modeling capabilities; 3. development ofremote sensing data analysis capabilities; and 4. creation of specialized data bases and products as required by users.
Sediment Loads in Reelfoot Creek Watershed, Tennessee
Year: Authors: Kung H., Garrett J.
Although sediment loading has been identified as Reelfoot Lake’s major problem, a detailed examination is needed to understand the ratio between the amount of soil loss from the critical erosion areas and the amount of sediments actually transported to the streams and lake. Because of the detrimental effects of sediments on water quality, there is considerable interest in determining the primary sediment Figure I sources and percentage of soil loss transported sediments in streams and lakes. The purpose of this study is (I) to calculate the annual soil loss (in tons) from critical erosion areas by subwatersheds in the Reelfoot Creek Basin watershed; and (2) to sample and analyze the stream water sediment load (total suspended solid load). From this ratio (sediment delivery ratio) or percentage between stream sediments and soil erosions can be determined.
Potential Development of Fresh Water Resources from the Lower Wilcox Aquifer in the Heidelberg Oil Field, Heidelberg, Mississippi
Year: Authors: Hille F., Hoffmann J.H., Erustun K.H.
In the production of oil, salt water is commonly brought to the surface as well. This occurs because most hydrocarbon reservoirs occur within saline water-bearing formations. As the oil is produced, salt water migrates into the pore spaces formerly occupied by the oil, typically resulting in the production of a decreasing quantity of oil and an ever-increasing amount of salt water. At the surface, the salt water is separated from the oil and is normally disposed of in an injection well through which it is pumped back into a subsurface saline water-bearing zone that may be shallower than the producing intervaL Salt water produced in conjunction with oil production at Heidelberg (Figure 2) reportedly ranges from 47,000 to 168,000 milligrams per liter dissolved solids. Since 1950, approximately 410,000,000 barrels of oil field brine have been injected into the sands in the lower part of the Wilcox Group in the vicinity of Heidelberg.
Made Project Underway at Columbus Air Force Base
Year: Authors: Betson R.P.
The Electric Power Research Institute (EPRI), sponsored by the electric utility industry conducts a wide-ranging research, development, and demonstration program. All aspects of electricity generation, transmission, and distribution are addressed by this research effort. Since the utility industry burns coal for generation of electricity, it generates large quantities of solid wastes. The potential for ground-water contamination from the disposal ofthese waste products is a major concern of the utility industry. In addition, EPA’s new mandate under the RCRA amendments, along with its new ground-water protection strategy and tighter permitting requirements by the States have served to focus attention on groundwater protection. In response to concerns by member utilities, EPRI initiated the Solid Waste Environmental Studies (SWES) project in 1983 to develop data and methods for predicting the fate of chemicals associated with utility solid wastes which may leach and enter ground waters. An extensive survey of utility personnel conducted prior to initiation of the SWES project revealed that fully satisfactory methods for predicting the fate of chemicals in the ground-water system do not exist and that EPRI should conduct a research program to develop effective models (Science Applications, Inc., 1982; Murarka, 1982).
Irrigation Using Surface Water - An Alternative to Ground Water Overdraft
Year: Authors: Forbes R.E.
The emphasis of this research was to perform an analysis of the options to be considered when using surface water as an alternate to ground water for irrigation purposes. The purpose of the project was to identify problems that may hinder widespread use of surface water, evaluate equipment suitable to use surface water, provide an economic analysis comparing costs involved, and make recommendations concerning the use of surface water in place of ground water. Present irrigation practices and equipment were examined during the course of this study. This study consisted of an extensive literature survey, attendance of workshops, discussion with farmers and equipment vendors, and site visits to irrigated farms and suppliers ofequipment. General conclusions following this phase ofthe work were: 1. Well water is generally used for irrigation, in lieu of surface water, due to its present availability and because it is cheaper. Any encouragement to use surface water for irrigation will have to come (at least in the immediate future) because of economic advantages which its use may offer. 2. There are no generally acknowledged problems with surface water pumping equipment and this equipment is readily available from vendors. 3. Catfish farming operations do not generally provide appreciable quantities of water which may be used for irrigation. 4. Present rice growing practices may produce situations where excessive water use results. The reuse of such water in a center pivot system will be subsequently discussed.
Status Report on a Formation of a Delta Water Management District
Year: Authors: Morgan C.
In the latter part of the decade of the 1970’s, Delta Council recognized that expanding acreages of irrigated rice and the potential growth of the farm-raised catfish industry in the Mississippi Delta would be contributing factors toward the need to carefully study the hydrology ofthe alluvial aquifer in the Mississippi Delta region. This region, an abundant source of quality water at very shallow depths, has become an essential part of the Delta’s agricultural system in row crops, rice and catfish production. It is with this understanding of the importance ofthe alluvial aquifer to the economy of the Delta area that Delta Council passed a resolution in 1979 requesting that the U.S. Geological Survey and the Mississippi Department of Natural Resources initiate a groundwater study.
The Passage of Mississippi’s Water Laws in Retrospect
Year: Authors: Deaton C.
The hardest task in life is to get someone in the middle of a forest to appreciate a tree - but place him in the desert and a tree is a gift from heaven. In past years this situation has existed with ground and surface water in Mississippi. We would pass free flowing wells and open faucet without a moments’ thought. Flood control and drainage have been foremost in the minds of our lawmakers. Water quality has been a growing concern due to Federal money and regulations concerning health needs. In 1956, the State of Mississippi enacted legislation dealing with permitting surface water use due to efforts of some far-sighted people like Sam Thompson and are unusually dry farming season. It wasn’t until the late 1970’s that certain areas like Tupelo and parts of the Mississippi Delta became alarmed about ground water. The newly created Department of Natural Resources working with a few State dollars and assistance of the Geological Survey confIrmed possibilities of ground water problems. The increasing use of ground water for rice, catfish, and other agricultural uses in the Delta coupled with a drop in the level of the aquifer supplying this water prompted an appropriation for the Department of Natural Resources for additional survey of the ground water in this area.
A Computer Simulation Model for Biological Control of Aquatic Plants
Year: Authors: Akbay K.S., Wooten J.W., Howell F.G.
A first generation computer simulation model has been developed for biological control of waterhyacinth (Eichhornia crassipes (Mart.) Solms.) by two species of weevils (Neochetma bruchi Hustache and N. eichhorniae Warner). In this paper, the conceptual model is presented. It is a dynamic model which simulates the plant growth, insect development, and the plant-insect interactions on a daily basis. This model will allow aquatic plant managers to evaluate different control strategies before they are actually implemented.
Groundwater Protection at the Local Level
Year: Authors: Matthews M.R.
In fiscal year 1984, the Tennessee Valley Authority (TVA) Conducted a Groundwater Situation Assessment of the Tennessee Valley Region (1), Two of the primary conclusions of that assessment were that more work needed to be done to educate the public about groundwater and more work should be done on groundwater protection, not cleanup. A demonstration was initiated in the First Tennessee Development District (FTDD) of upper east Tennessee in 1984 to address these two needs. The State of Tennessee, the FTDD and the TVA cooperated in demonstrating the implementation of local government groundwater protection plans. Eight counties, twenty-four public water supplies, and forty-three water sources were involved. It is the intent of this paper to describe the process local governments can go through to protect their groundwater supplies. The approach to protection used in the FTDD demonstration will be the basis of the discussion.
Estimating Agricultural and Fish and Wildlife Water Demands: An Essential Component of Water Use Management
Year: Authors: Reinschmiedt L.L., Laughlin D.L.
The U.S. Army Corps of Engineers, Vicksburg District, contracted with the Department of Agriculture Economics at Mississippi State University in 1982 to estimate the agricultural and fish and wildlife water demands for the Yazoo River Basin to the year 2030 as a part of their overall water supply study for the Yazoo River Basin. The purpose of this paper is to describe the methodology developed to provide the crop and fish farming water use estimates requested by the Corp of Engineers and to emphasize the methodology’s applicability for water use management. The paper is divided into four major components. First, the issue of why the development of water management systems will be increasingly important in the future and how research can be an integral component of the water management process are addressed. Secondly an overview of a model that was developed for examining agricultural and fish and wildlife water demands in the Yazoo River Basin of Mississippi is presented. Thirdly, selected results from the model depicting water requirements for 1980-2030 are shown to exemplify use of the model for purposes of projecting water demands. Finally. the paper concludes with a discussion of how the model can be used in combination with other data bases to assist decision makers in the development of water management policy.
Economic Considerations of Potential Solutions to Ground Water Overdraft in Mississippi
Year: Authors: Cheatham L.
Minimum acceptance standards for quantity and quality vary greatly among users. Demand for water will obviously be greater for industrial and agriculture users, but it will also vary greatly among users in each of these groups depending to a large extent on size of firm and type of industry and on size of farm and type of crops. Likewise, for the household users, the minimum criteria vary. This is especially true in connection with quality. Every small public supply system in the state has probably encountered situations where some customers chose the public system because their private wells did not provide acceptable quality while other residents chose to use private wells because the public supply did not measure up to their standards of quality. Ground water in the state of Mississippi has measured up very well in terms of quantity, quality, and cost criteria for a large portion of all types of users. This is why approximately 43% of the over 3.5 billion gallons per day of total water intake in the state is withdrawn from this source. Most of the ground water intake is accounted for by the categories of domestic, industrial, and agriculture related uses. Management of ground water in an overdraft area mandates that tools employed to control use focus on the causes of the problems. The portion of a county’s ground water intake accounted for by each of these three major categories of use provides the basic indicator of the focus for water management. It is preferable to develop management tools with as much universal applicability as possible. This is especially true in view ofincreased concentration of management authority at the state level that occurred when House Bill 762 of the 1985 Legislature revised portions of the code dealing with water management. The logical process is to identify those areas of the state where ground water overdraft is a problem, and determine the minimum number of homogeneous overdraft classification groups based on mutual factors responsible for the overdraft.
An Analysis of Potential Impacts of Alternative Institutional Arrangements on Development of a Specialty Crop Industry in Southeastern Oklahoma
Year: Authors: Dale J.F., Schatzer R.J., Nelson J.R.
Just as in any development project, cost may be an impediment to the development of surface water irrigation systems. Providing adequate water for irrigation on a representative plot size for the area (2.5-10.0 acres) requires an investment of approximately $10,000 to $15,000. This investment would provide the structure, distribution system, motor, and pump. In light of the potential for substantial benefits from development of a southeastern Oklahoma specialty crop industry and the large investment costs required, there is a need to consider the advisability of using public funds to subsidize the construction of water structures. The overall objective ofthe study and the specific objectives of this paper are presented in the next section. Then procedures used to accomplish the paper’s objectives are discussed, followed by brief comments about types of data used and sources from which these data were drawn. The last two sections of the paper include a presentation of analytical results and a discussion of the conclusions drawn from these results.
Use of Fluvial Geomorphologic Knowledge to Reduce the Cost of Bank Stabilization in Northern Mississippi
Year: Authors: Winkley B.R.
Rivers in a natural environment establish definite patterns that are the result of the drainage basin’s geologic history, the available sediments and the hydrologic input. If the river engineer will recognize these natural controls, a more economical, more aesthetically acceptable and ecologically adjustable means of improving stability can be constructed. This paper presents this fluvial geomorphic approach on a Northern Mississippi unstable stream.
Comparison of Flood Frequency from Synthetic and Observed Data on Small Drainage Areas in Mississippi
Year: Authors: Colson B.E.
The U. S. Geological Survey and the Mississippi State Highway Department have a long-standing cooperative program of waterresources investigations, one element of which is the continuing investigation of the flood frequency of streams in Mississippi. In 1955, the Survey began the systematic collection of peak-flow data on small drainage areas in Mississippi. In 1964 the Survey entered into a nationwide program sponsored by the Federal Highway Administration to study flood frequency of small drainage areas. The Mississippi District of the Survey, in cooperation with the State Highway Department, expanded the streamgaging network for small drainage areas to a total of 95 sites to collect rainfall and runoff data. Gages were relocated or discontinued for various reasons resulting in fluctuations of the number of stations operated during the study. During this time, the nation was involved in a massive highway construction program which required hydraulic design of stream crossings. It was deemed undesirable to wait for the collection of longterm flood records on small streams for frequency analysis. The Survey developed a rainfall-runoff model (Dawdy and others, 1972) to generate flood peaks using available long-term rainfall data. The model was calibrated for each of the gaging sites by optimizing 10 basin parameters using concurrent precipitation and runoff records (table 1). It was determined during the calibration process that four of these parameters -- DRN, EVC, RR, TP/TC (table 1) - could be held constant. Subsequently, each set of parameters was used in the model with long-term climatic records collected by the National Weather Service at Meridian and Vicksburg, Miss., Memphis, Tenn., and New Orleans, La., and pan-evaporation data from Mississippi State University to generate synthetic flood records. The frequency analyses of these synthetic records were used to prepare the statewide report, "Flood Frequency of Mississippi Streams" (Colson and Hudson,1976). Upon completion of this report, it was recommended that the small streams network be continued until at least 20 to 25 years of record was available to assess the validity of the synthetic flood-peak data. In 1977, a technique described by Moss and Karlinger (1974) was applied to the streamgaging network. This analysis indicated that 80 percent of the information could be obtained from 45 sites chosen to represent a broad range of stream characteristics. The small basin gaging station network was reduced to 45 sites during 1977. The reduced network was operated through the water year ending September 1984. The Survey agreed to make a comparison of the synthetic data with results from observed data through 1984. This report provides a comparison of the synthetic flood-frequency values used in the first report "Flood Frequency of Mississippi Streams" and the values computed from observed annual peaks through the 1984 water year. Fifty-one sites that have 16 years or longer record are used in this report for comparison with the synthetic results (fig. 1).
Water Management Aspects of the Tenn-Tom Waterway
Year: Authors: Burkett E.
In December 1984 the final segments of the Tennessee-Tombigbee Waterway were completed. The Waterway connects the Tennessee River to the Gulf of Merico at the City of Mobile. The project starts from the existing Black Warrior-Tombigbee channel at Demopolis and generally follows the Tombigbee River to its headwaters and cuts through the basin divide to connect to the Pickwick Reservoir on the Tennessee River. The total length of the project is 234 miles with 10 locks and dams which raise the water surface a total of 340 feet. The project can be divided into three distinct parts. The first part, known as the river section, consists of 4 low-lift locks and dams and channelization along the existing river alignment. Upstream of this section a series of poola were created along the left bank edge of the river valley. Five locks and dams raise the water level 140 feet in a distance of 46 miles along this Canal Section. At the upstream end of the canal section a high-lift lock and dam (84 feet) raises the water surface to the level of Pickwick Reservoir on the Tennessee River, 414 feet above sea level. A 39 mile channel excavated through the river basin divide completes the project to the Tennessee River. These major features are shown on Figure 1.
Investigation of shallow hydrogeology at the plastifax site, Harrison County, Mississippi
Year: Authors: Erustun K.H., Hoffman J.H.
On June 2, 1982, the Plastifax plant near Gulfport, Mississippi, was destroyed in a massive explosion resulting from an accident in an on-site manufacturing process which was believed to have occurred when employees were trying to formulate a chemical from diesel fuel, paraffin and nitric acid. One of the main products of the facility was chlorinated paraffin. The explosion was believed to have caused a rel ease of hazardous chemicals to the environment which prompted an immediate investigation by State and Federal agencies. The Plastifax plant site is located in Harrison County, Mississippi, on the north bank of the Bayou Bernard Industrial Canal. This site is approximately one mile east of the intersection of the U. S. Hwy 49 and Interstate 10. Industrial Seaway Road forms the northern boundary of the plant as it runs parallel to the bayou. This is an area oflow topographic relief with elevations ranging from 25 feet above mean sea level about one-half mile north of the plant to less than 5 feet at the surface of Bayou Bernard. Average elevations at the plant itself range from 17 to 22 feet. The location is one of dense industrial development. The Chemfax plant is located on the western boundary of Plastifax and the Charter Oil Company terminal shares access to the bayou on the south boundary of the site. Previous investigations of groundwater contamination consisted of drilling a series of shallow bore holes in and around the plant site for the purpose of collecting soil samples, installing a series of shallow piezometers for the purpose of monitoring water levels, and a network of five monitoring wells was designed for the purpose of collecting water samples from the shallowest aquifer in order to determine whether or not any contaminants were present in this zone. During the course of drilling these wells, the shallow subsurface material was described in driller’s logs and a coefficient of permeability value of 2.0 ’" 10-7 em/sec was obtained from are molded sample collected from monitoring well MW-2. Water levels were measured occasionally in the piezometers and later in monitoring wells.
Analysis of backwater at the I-10 crossing of the Pearl River in Southeast Louisiana and Southwest Mississippi
Year: Authors: Lee J.K., Froehlich D.C.
In April of 1979 , 1980, and 1983, major flooding on the lower Pearl River in Louisiana and Mississippi caused extensive damage to homes located on the flood plain in the Slidell, La., area. Both the 1980 and 1983 floods overtopped the Interstate Highway 10 (1-10)crossing of the Pearl River flood plain between Slidell and Bay St. Louis , Miss., interrupting traffic for several hours in 1980 and several days in 1983. Many local residents attributed part of the 1979, 1980, and 1983 flooding in the Slidell area to backwater caused by the 1-10 embankments and the U.S. Highway 90 embankments about 5 mi downstream from 1-10. The U.S. Geological Survey, in cooperation with the Louisiana Department of Transportation and Development, Office of Highways, and the U.S. Department of Transportation, Federal Highway Administration, undertook to quantify the effect ofl-10 and Highway 90 on water-surface elevations and flow distribution during the 1980 flood and quantify the effect of several alternatives for reducing backwater on water-surface elevations and flow distribution (Lee and others, 1982 , 1983; Wiche a nd others, 1982). The two-dimensional finite-element surface-water flow modeling system FESWMS was used to study the effects of l-lO and Highway 90 during the 1980 flood and to evaluate the hydraulic effect of alternatives for reducing backwater. The model can be used to simulate both lateral and longitudinal velocities and variations in watersurface elevation, highly variable flood-plain topography and vegetative cover , and geometric features such as highway embankments, dikes, and channel bends. Geometric features of widely varying sizes are easily accommodated within a single finite-element network. This paper describes the part of the study involving the 1-10 crossing. The paper begins with a brief description of the modeling system FESWMS and a description of the study area. Data collection, network design, and model calibration for the 1980 flood are described. Results of the simulation of the 1980 flood both with and without 1-10 in place are presented, and backwater and drawdown caused by the roadway are discussed . The simulation of flow for a modifi cation of the 1-10 crossing is also discussed. Throughout this paper, the words "backwater" and "drawdown" denote an increase and a decrease, respectively, in water-surface elevation caused by a flood-plain constriction. Backwater may occur both upstream and downstream from the constriction. Elevations refer to the National Geodetic Vertical Datum (NGVD)of 1929, called sea level in this report.
Model studies of Steele Bayou drainage structure and outlet channel and repairs to outlet channel
Year: Authors: Arthur B.K.
Outlet channel degradation is typical downstream of all hydraulic structures which discharge into the yazoo River from the yazoo backwater area. Since completion of each drainage structure on the yazoo backwater area, there has been a continuous instability problem in each downstream outlet channel. After the severe flood outflows during the spring of 1983. significant bottom scouring and bank sloughing were noted in Steele Bayou Outlet Channel. Model studies were conducted to define performance of the existing stilling basin and causes of problems in the outlet channel and to develop practical modifications that will permit the structure and outlet channel to perform satisfactorily for all anticipated flow and operational conditions.
Use of two-dimensional modeling system to evaluate lock channel shoaling at Lock and Dam No. 1 on the Red River Waterway
Year: Authors: Little Jr. C.D.
The Red River Waterway is a Corps of Engineer project designed to provide nine foot navigation from the Mississippi River to Shreveport, Louisiana. Five locks and dams along the Red River will provide a nine foot by 200 foot navigation channel adequate for twoway navigation. The purpose of the investigation was to evaluate the flow conditions at the problem area, and to develop a tool to facilitate engineering decisions of possible solutions by alternative analyses.
Ground-water development alternatives in the Natchez area, Mississippi
Year: Authors: Boswell E.H., Bednar G.A.
The Natchez municipal water supply is obtained from aquifers that occur at depths of 400 feet and 600 feet in the strata of Mioceneage. Several public water-supply wells obtain water from a deeper Miocenestratum. that occurs at a depth of about 1,000 feet and some small water supplies are obtained from wells less than 200 feet deep that tap the post-Miocene sediments in the uplands. Most of the ground water used in the area is pumped from the Mississippi River alluvial aquifer for industrial use. Although the Mississippi River is the western boundary of the City of Natchez, it has in the past not been used as a water-supply source because of treatment requirements and the availability of ground water. The largest source of surface water, excepting the Mississippi River, is the Homochitto River. These streams are not convenient sources of water for most of the county and for most uses the water would require treatment. Dependable surface-water supplies are limited in most of Adams County, and some streams have been subject to pollution for many years (Callahan and others, 1964, p. 21; Childress and others, 1976, p. 122). Recently, the U.S. Geological Survey completed an appraisal of the current ground-water situation and of the potential for increasing the ground-water supply in the Natchez area (Boswell a nd Bednar, 1985 ). Ground-water data were needed for planning expansions of public water supplies and for efficient development of the area’s water resources.
Agricultural conjunctive use in the Delta
Year: Authors: Arant H.M.
Agric ulture is an d will remain Mississippi’s largest industry. This state has been blessed with 17.4 million acres afforest land and about 10.9 million acres of soils th at are recognized as pri me and unique farm land.
A water management system for Mississippi
Year: Authors: Sage A.
The following analyses of House Bill Nos. 762 and 149 are provided for legislation currently under consideration by the Mississippi Legislature. If the proposed legislation is adopted without substantial change, Mississippi will have a true management system for water resources. The new regulatory system is set out in House Bill No. 762, which substantially amends the present surface water permit system. The prior appropriation doctrine is eliminated and a true permit system is created. Ground water is included in the coverage of the act so that this resource can be managed, and conjunctive use is encouraged. House Bill No. 149 creates a new type of water management district to resolve some of the problems posed by present law. The introduction below discusses the reasons for creation of such a district. The new permit system is actually not a radical departure from current law. Many of the present provisions are retained in substantially the same form. The elimination of prior appropriation, although a radical change at first glance, reflects the necessity for a more flexible method of allocation. The inclusion of ground water in the statute will allow regulatory authorities to encourage both conjunctive use and greater utilization of surface water resources. However, the new system essentially is patterned on many other systems throughout the country. Existing rights are preserved, but provision is made for the termination of stale uses . Permits must be renewed every ten years, allowing regulatory agencies to re-evaluate water uses. A state water management plan is mandated, and the Commission on Natural Resources is authorized to promulgate regulations based on the plan for management of the state’s water.
An evaluation of the effects of water shortages upon regional economic transactions
Year: Authors: Nissan E., Williams Jr D.C.
In many regions in the country and especially in Mississippi, most of the water for residential, commercial . industrial, and municipal purposes is supplied from ground water sources. Adequate water is necessary for economic growth and development . At times, water shortages occur. This could hinder future development or even curtail current production. Hence. it becomes necessary for planners to quantify the consequences on the economy. The purpose of this paper is to present a theoretical model whereby a systematic analysis of information upon which decisions in regard to expansion of water services may bemade. More specifically, assume that production of certain types of industries of given sizes and developments is curtailed in an area due to a moratorium for insufficient water. The loss of economic activity foregone may be assessed. A hypothetical example will be provided.
Expanded Floodplain Information Study for the Wolf River Basin, Tennessee and Mississippi: A Computer Simulation
Year: Authors: Engdahl T.L., Collins J.C.
Seemingly, every few weeks a flood of catastrophic proportions occurs somewhere within the U. S., recently in Houston, Texas, and Lake Charles, Louisiana, and just months ago on the Mississippi Delta and in Jackson, Mississippi. The apparent frequency and severity of such events are, to a degree, due to improved news media coverage and public awareness. On the other hand, though, such events are in reality occurring more frequently, and the impacts are becoming more substantial. Independently, decisions are made to modify upland, floodplain, and channel regimes. Singly, the impacts of such changes may be minor but in concert, sometimes devastating.
Enhancement of Release Water Quality by Localized Mixing Lake Okatibbee, MS
Year: Authors: Wilhelms S.C.
There are several methods of improving the quality of releases from such a lake. If cold water releases are desired, hypolimnion oxygenation or reaeration through the structure will improve the release quality. If warm releases are desired, then artificial destratification, addition of selective withdrawal capabilities, or localized mixing are alternatives for enhancing the downstream quality. Artificial destrntification mixes the entire lake redistributing water quality constituents throughout the waler column. However, destratifying a large water body can require a large amount. of energy. Add-on structural modification for selective withdrawal can provide direct withdrawal of epilimnion water but has a very high first cost. Localized mixing enhances the release quality by forcing epilimnion water downward to be mixed and withdrawn with hypolimnion water. Localized mixing, when applied appropriately, can maintain lake stratification while providing an economically attractive means of improving release quality. Localized mixing will only partially enhance release quality, whereas structural add-ons for selcctive withdrawal provide maximum improvement by releasing" water of desired quality.
Quick Estimation of Parameters of Muskingum Method of Flood Routing
Year: Authors: Singh V.P., McCann R.C.
This paper determines the Muskingum parameters using (1) least squares method, (2) method of moments, (3) method of cumulants, (4) graphical method and (5) direct optimization. An example is worked out to evaluate the efficiency of each method. It is shown that it is far more convenient to estimate the parameters by either of the four other methods, and that there may exist more than one set of parameters leading to comparable results, (H) B = YIZ2 ~ ZlY2 (9,,) , Z2Yl - )’2ZJ Thus we obtain: , I ~ ~IS’~II-SIiII’=>""" (7) I I where S (j) is the observed storage for the j-th time intervul, S {j) the estimated storage for the j-th time interval and N the number of data or times of observations. E is the error function to be minimized. Equatioll (7) can be written as (dropping j for brevity)
Two Approaches to Identify Storm Water Runoff Loads
Year: Authors: Doyle, Jr. W.E., Jennings M.E.
By the early 1970’s it was becoming apparent that man’s land use activities were seriously affecting the water quality of the nation’s streams. Even though pollutants, that is, high concentrations of certain water-quality constituents, from "point" sources such as industrial and municipal locations in urban areas were substantially reduced, serious levels of pollution remained and were attributed to "nonpaint" sources including storm-water runoff from urban areas. To aid in urban stormwater planning, the U.S. Geological Survey (USGS) is developing methods of identifying non-point pollution based on data collection and modeling concepts. After outlining storm-water quality planning approaches, this paper describes two studies recently completed in Houston, Texas and Miami, Florida. The studies are representative of pilot USGS activities in urban storm-water hydrology.
Statistical Analysis of Stream Events
Year: Authors: Zitta V.L., Mowry B.A.
An innovative technique for disposal of lagoon or other treated wastewaters has been under study at Mississippi State University (3,1) utilizing the stochastic nature of stream flows to minimize the detrimental effects of wastewater discharge on stream quality and stream aesthetics. This technique has evolved from continuous wastewater discharge proportional to stream flow magnitude (3), to intermittent discharge during the rising portion of stream events (1). Thus waste discharge is made at optimum stream transport and assimilative capacities while zero waste discharge is made during the recession portion of the discharge time series. To implement such a discharge scheme a detailed study must be made of hydrologic time series to determine the properties of stream flow applicable to this discharge technique.
Tennessee-Tombigbee Corridor Area: Growth Forecasting and Management
Year: Authors: Galdis A.V.
The concept of a Tennessee-Tombigbee Waterway predates even the agency which is buildingit, but the fundamental reason for the project has remained the same for over 200 years: to provide a trade route bet\lleen the mid-continent of North America and the Gulf Coast. Much was written about the benefits ofsuch a route, and many surveys were made, butit was not until after a re-evaluation in 1967 that pre-construction planning and engineering was accomplished, between 1967 and 1970, and construction of this transportation artery officially began in 1972. It soon became apparent that engineering, designing and constructing the waterway itself could be supplemented by planning activities which would allow the areas most affected by the project to take advantage of the potential for economic development. Responding to this need, Congress directed the Corps of Engineers to undertake a study to address these issues.
Computerized Agricultural Crop Food Damage Assessment System
Year: Authors: Hobgood W.B., Hill, Jr. T.C.
Many of the more critical water resource problems in the Nation have been resolved by approved water resource projects or have been addressed by a feasibility analysis. These projects reflected the changing needs and demands of the American people in regard to water resources development and have contributed signifieantly to the increased economic growth of the country and the overall well-being of its people. The need for water resources development continues, as evidenced by the recent flooding problems in the Mississippi Valley and the increased need for hydroelectric power. Civil works flood control planning will require closer scrutiny offuture studies from the standpoint of economic feasibility.
Income Distribution and Water Resource Projects: Testing the Classical Theory of Economic Development
Year: Authors: Eatherly B.J.
Large-scale water resource projects offer social scientists special opportunities, since by their very nature they do tum out something ofa controlled social experiment. Into a region where life has proceeded smoothly and continuously for some time, a sudden flow of oonstruction activity is infused, one which will ultimately change the sales and purchase opportunities open to residents for some time to come. I suggest in this paper that such projects offer excellent prospects for leaming more about the benefits and costs of industrial growth, especially about who benefits from such growth and who bears the costs and how the benefits and costs affect attitudes toward the project which brings change.
Reaeration Tests, Enid Lake Outlet Works
Year: Authors: Tate, Jr. C.H.
The primary objective of the Enid Lake tests was to :iemonstrate that the radioactive gas tracer technique can be applied to reservoir outlet works and to develop the techniques to :ollect tracer samples in and around the outlet structure. As a result, the gas transfer characteristics of the Enid Lake outlet works would be available for comparison with model data to :let.ermine the scaling relations for the technique. Dr. Tsivoglou was placed under contract with WES to assist WES personnel in the performance of the Enid Lake tests and to ;>rovide the laboratory analysis of the samples. In addition, Dr. rsivoglou’s radioactive materials license was used to conduct the tests.
A Remote Monitoring System for Water Quality Parameters
Year: Authors: Hart E.D., McCleave E.W.
The Waterways Experiment Station (WES) assists the Corps field offices by conducting research and developing new methods and equipment for their use. Much of the development work is concerned with data acquisition and storage utilizing modem, electronic equipment. The information is provided to the field offices through published reports, conferences, and/or demonstrations. Once adopted by the district, WEB acts as a consultant to insure continuous and effective utilization of the equipment. An example of this is a remote data acquisition and storage system which is being developed by the Instrumentation Services Division of WEB at the request of the WEB Hydraulics Laboratory. The system will acquire, process, and record wave data at remote sites. Use of the system is not restricted to waves. Water quality parameters could be monitored and stored in increments of appropriate units.
Sediment Sources and Yields from Upland Watersheds in North Mississippi
Year: Authors: Dendy F.E., Ursic S.J., Bowie A.J.
While information is available on erosion rates from various sediment source areas, a satisfactory method for accurately predicting sediment yields for large mixed-cover drainage basins is not. The method most commonly used for agricultural watersheds is to compute erosion rates for various categories of land use. Normally the universal soil loss equation is used to compute sheet and rill erosion, and gully and channel erosion rates are estimated or based on local field measurements (11). A sediment delivery ratio is then applied to the computed erosion rates to obtain estimated sediment yields at some location downstream (4) (6) (7).
Tennessee-Tombigbee Waterway: Planning History
Year: Authors: Currie F.L.
The idea of a navigable waterway connecting the Tennessee River and the Gulf of Mexico at the Port of Mobile has been a topic of discussion and the dream ofmany since the days of the early explorers. Hecords of the early 1700’s contain a map drawn by Bienville, founder of Mobile, to show the King of France the advantages of a canal connecting the Tennessee and Tombigbee Rivers.
Tennessee-Tombigbee Waterway Project Design and Construction Activity
Year: Authors: Thompson F.G.
In 1972 physical construction was initiated on the much discussed Tennessee-Tombigbee Waterway. The Waterway will connect the Tennessee River at Pickwick Lake with the Tombigbee River at Demopolis, Alabama, on the existing Black Warrior-Tombigbee Waterway, thereby providing shortened routes between shipping points of mid-America with the deepwater ports along the northern Gulf coast. Inland points and internstional ports will be provided with low costwater transportation.
Tennessee-Tombigbee Waterway: Project Operation, Cultural and Recreation Resources Development
Year: Authors: Melton G.L., Nielsen J.J., Topper E.
The Corps of Engineers is authorized and required, under several Federal acts and public laws, to assess and develop the cultural and recreational resources of Federal water resource projects such as the Tennessee-Tombigbee. A major cultural resources program has been developed for the Tennessee-Tombigbee Waterway as an integral part of the overall environmental studies. It represents one of the most comprehensive programs of its type in the nation. The investigations are being designed and implemented in cooperation with the states of Alabama and Mississippi, as well as several other Federal agencies. Likewise, studies to evaluate the recreation potential and determine the land and facility requirements needed to accommodate the projected recreation visitors on the waterway have been completed. The studies have been coordinated with local, state and Federal agencies in Alabama and Mississippi to insure compliance with the Statewide Comprehensive Outdoor Recreation Plans.
Mississippi Dam Safety Program
Year: Authors: Pepper J.W.
Many of us have been guilty of making statements about the "abundant water resources in Mississippi." Obviously, this has usually been true. In fact, the greatest problem in the water management field is still that of handling the excess flows. Flood control and drainage have always received a high priority in Mississippi. Levee districts and drainage districts were authorized by some of the earliest legislation on record. Prior to the Civil War, levees and drainage ditches were being constructed in most parts of the State. The first dams built in Mississippi were for the purpose of operating small mills. Some of these dams are still in existence today.
Variations of a Mississippi River Crossing with Stage
Year: Authors: Hines, III J.V.
In the study of sediment transport by rivers, most of the emphasis has been directed toward bendways and channels having a smooth, regular shape. Very little investigation has covered crossings. One possible explanation for this is that flow characteristics do not differ much among different bends, but crossings may be found which are quite unique within relatively long reaches of river.
A Field Test of Environmental Impact Assessment in the Tensas Basin
Year: Authors: Peterson J.H., Clinton C.A., Chambers E.
In the years since the passage of the National Environment Policy Act (NEPA) and related legislation, there has been a major effort on the part of all federal agencies to develop regulations, procedures and guidelines for meeting the NEPA requirements for impact assessment. Presently, four different impact accounts are required in response to water development plans. These are the National Economic Development account (NED), the Environmental Quality account (EQl, the Regional Development account (RD) and the Social WeD-Being account (SWB). Part of the difficulty lies in the fact that procedures for analysis under the National Economic account have been tested and clarified for over 40 years. The Environmental Quality account has been under development for over 10 years, while the Social Well-Being account has only recently been stressed. The different stages of development of these accounts poses a difficulty for the realization of an interdisciplinary assessment of impacts mandated by NEPA.
Runoff Composition of Soybean Management Systems on Leeper Clay Loam Soil
Year: Authors: Romkens M.J., Wang J.Y., Whisler F.D., Buehring N.W., Young J.K.
This article discusses the results of measurements of soil loss and chemical composition of runoff from various tillage management systems on bottomland during simulated rainstorms. The specific objectives are (i) to report soil erosion rates for two commonly occurring land management systems on bottomland soil in soybean production following harvest during the fall of 1977. (ii) to report on the chemical composition of runoff from these systems.
Performance and Effects of SCS Floodwater Retarding Structures in the 1979 Easter Floods
Year: Authors: Forsythe P., Ulmer R.
Performance of the 8CS floodwater retarding structures and farm ponds during the intense April storm can be termed nothing short of excellent. This is not a biased statement. Reports from Mayor Glasgow of Ackerman: "The Soil Conservation Service watershed project helped us avoid absolute disaster during the recent flood. Without this project, we’d have been in the same position as Jackson. Ifwe hadn’t had the project, we would have had one-half of the town and half the businesses, including the Courthouse, inundated. But, because this project protected us, water didn’t get into a single commercial building, and only three houses had a slight amount of water."
Geologic and Geomorphic Aspects of Streambank Erosion in the Yazoo Hill Streams
Year: Authors: Rentschler R.E.
Erosion is a natural geological process that has been occurring without hesitation since the creation of the earth some41/2 billion years ago. Without erosion and the subsequent depositional process, the Yazoo Basin and earth as a whole would have characteristics of an entirely different nature. Within the Mississippi Embayment, virtually all the landforms on the surface and subsurface strata to a considerable depth are of sedimentary origin. Without erosion acti vely taking place in the uplands, thus producing sediments which were deposited in the lowlands, the landscape of the lowlands would only be igneous metamorphic formations much lower in elevation than the present surface.
Determination of Effects on Channel Modifications on Flow Characteristics
Year: Authors: Combs P.G., Raphelt N.K., Allen M.W.
This paper will present a method of analyzing the channel modification. The methodology presented in this paper uses techniques available to the practicing engineer and can easily be applied to similar problems.
Hydraulic Criteria Used in the Inspection and Evaluation of Non-Federal Dams
Year: Authors: Combs P.G.
Recent dam failures on federal and non-federal dams have increased the public interest in dam safety. The Corps of Engineers has initiated the inspection and evaluation program of non-federal dams. This paper addresses the hydraulic analyses necessary to determine spillway capacities and the downstream hazard potential. The analyses determine probable maximum precipitation (PMP) for the particular drainage basin, and investigate the capability of the reservoir to route the PMP through the outlet works without overtopping the dam. On-site investigations are made to determine the hazard potential of a dam break.
An Innovative Approach for Removal of Iron from Mississippi Groundwaters
Year: Authors: Mitchell G.F., Bond M.T.
Comprising about five percent of the earth’s crust, iron is present in almost all groundwater due to its abundance in a wide variety of crystalline rocks and soils. When groundwater is used as a water supply, the presence of iron in significant concentrations is objectionable because it supports the growth of microorganisms, produces unaesthetic conditions, and results in financial loss. In order to curtail these problems, the Environmental Protection Agency has set 0.3 mg/I as a maximum secondary standard for iron in potable water.1 In the State of Mississippi, it is reported that 59 of the groundwater supplies exceed this recommended limit.2 Necessarily, many Mississippi well supplies must be treated to remove the objectionable iron. Most current treatment methods consist of oxidizing the iron to the insoluble state and subsequent removal and disposal of the precipitates formed. This paper presents an innovation to the current technology-recirculation of the precipitates to achieve improved iron removal.3
Thermal Analysis of Lake Greeson, Arkansas and Sardis Lake, Mississippi
Year: Authors: Stafford, III J.P.
The purpose of this study was twofold: (1) to determine the capability of a selected temperature change in two dissimilar, large manmade lakes, and (2) to apply the model to determine optimum discharge elevations to satisfy downstream water quality objectives for one of the lakes being studied. determine the capability of a selected temperature change in two dissimilar, large manmade lakes, and (2) to apply the model to determine optimum discharge elevations to satisfy downstream water quality objectives for one of the lakes being studied.
Impact of Status C Land Use Requirements for Flood Insurance Eligibility in Selected Mississippi Communities
Year: Authors: Cheatham L.R.
The continuing increases in flood losses and the resulting increases in government expenditures have raised questions as to the effectiveness of the land use requirements for flood insurance eligibility. A study was conducted by the Division of Business Research for the Water Resources Institute at Mississippi State University to examine the problem. The study was funded in part by the U.S. Department of the Interior through OWRTas authorized under the Water Resources Research Act of 1964.
Comments on Use of Economics in Public Project Evaluation
Year: Authors: Williams, Jr. D.C., Cartee C.P.
A number of factors enter into evaluation of public proJects. Some are economic while some are social political, engineering, etc. Each at one time or another influences decisions about initiating and evaluating a given project. Comments in this paper will be limited to selected economic factors. The weight, or importance, of economics in project evaluations varies over time and with individuals and projects. Nevertheless, it is fashionable to use-or misuse-economics. Often promoters and/or the news media associate economic terms with factors that imply conclusions that are economically incorrect. This is true of various types of public projects, including those that are water related.
Yazoo Basin - Streambank Erosion Control Evaluation and Demonstration Project
Year: Authors: Smith R.O.
The specific stream bank problems addressed in this paper occur on the hill tributaries to the Yazoo River above Greenwood and below Arkabutla Lake within the Yazoo Basin Watershed. Figure 1 is a schematic illustration of the demonstration area. Most of the small tributary streams in the Yazoo Basin probably looked like the stream in Figure 2 prior to settlement of the area. There were defined channels, vegetated to the top bank with a tree canopy overlapping the stream. Now, many of the streams have eroded badly. entrenched themselves deep into the highly erodible soils. and are choked with debris and sand (Fig. 3). Many factors have contributed to the deterioration, most all of them imposed by development of the area for agricultural and other land uses, such as urbanization and mining.
Cover, Slope, and Rain Intensity Affect Interrill Erosion
Year: Authors: Harmon W.C., Mayer L.D.
This interrill-rill concept of erosion was the basis for research by Lattanzi et al. (2) on interrill erosion. The researchers found that soil cover and slope steepness affected soil lost by runoff and raindrop splash from the study area. The significance of these findings prompted a further study of the interrill erosion process at the USDA Sedimentation Laboratory in Oxford, MS.
The Downstream Migration Rate of River Meander Patters
Year: Authors: Keady D.M., Priest M.S.
The purpose of this study was to develop a generalized relation from which the downstream rate of meander migration in alluvial materials could be determined. It was presumed that this could be accomplished, to some degree, by analysis of data already available in published reports on particular rivers, maps and related data, and airphotos and related data. The analysis would, of course, be subject to constraints imposed by the available data. Only relatively free meander patterns were considered. That is, those subject to minimal influence by man’s activities.
Bay Springs Canal Surge Study
Year: Authors: Tate, Jr. C.H.
The Bay Springs Canal Surge Study was conducted in the Hydraulics Laboratory of the U. S. Army Engineer Waterways Experiment Station (WES) in Vicksburg to investigate the effects of .releases from the proposed Bay Springs Lock on navigation in the downstream canal. During the design of the lock, the possibility for surging in the canal was recognized due to the 6.2 million cubic feet of water to be discharged over a l2-minute period.
A Discussion of Legislative Requirements for U.S. Fish and Wildlife Service Participation in Water Resource Development Planning
Year: Authors: Hardy J.W., Dawson R.M.
In recent years, Mississippi, like most other states, has witnessed a rapid increase in competition for development, management, and utilization of water resources to serve a wide variety of public wants. New demands for navigation, flood control, impoundments, and diversions for water supplies, electric power, agricultural expansion, sewerage disposal, and recreation have resulted in an increased awareness of environmental quality. Such has given rise to a proliferation of new legislation and policy requiring public agencies to reorder priorities on natural resource values in their planning and construction of water development projects.
The Influence of Turbidity on Planktonic and Benthic Organisms
Year: Authors: Burris J.W., Cooper C.M.
Descriptions of water quality are very often expressed in nebulous and broad terms. Essentially, the terms reflect the nature of the water as it affects the human responses of sight, smell, and taste; three factors which may have little correlation to actual biological condition of the system. Normally the description for visual response is turbidity. Smell and taste of the water may be indicative of degradation of the environment from organic pollutants and man’s activities in general. Turbidity, on the contrary, is more often associated with expected natural errosion and usually occurs to some degree regardless of the intervention of man. Increases in levels of turbidity beyond long-term levels, however, are very often encountered in systems in which man has intervened.
Plankton Production in a Small Mississippi Impoundment, Lake Lamar Bruce
Year: Authors: Knight, Jr. L.A., Herring J.
Counts alone do not provide an adequate estimation of plankton production. A more complete picture of plankton communities and the roles these organisms play in the overall aquatic food web can be obtained by supplementing plankton counts with information on organic content and photosynthetic activity. In this investigation, plankton crops were examined four times during the year in Lake Lamar Bruce, Mississippi to measure total volatile matter, oxygen production and numbers of organisms.
Sediment Deposition Rates in Three Small North Mississippi Reservoirs
Year: Authors: Dendy F.E., Champion W.A.
In the late 1940’s, the USDA Soil Conservation Service began an extensive erosion-flood control program in the Yazoo-Little Tallahatchie River basins. One conservation measure employed was to construct reservoirs on small upland streams to retard runoff of flood waters and to trap sediment below severely eroding drainage basins. This paper gives information on sediment deposition rates and amounts in three of these structures.
Initial Angler Harvest and Largemouth Bass Exploration in a New Mississippi Impoundment
Year: Authors: Herring J.
Tippah County Lake, a newly constructed 150 acre impoundment in northeast Mississippi, was allowed to fill during the winter of 1973-74. The Game and Fish Commission immediately began intensive study of the impoundmen t.
A Study of the Dynamic Rating Curve of the Mississippi River
Year: Authors: Combs P.G., Flowers D.
The purpose of this study was to determine whether the water surface profile for the design flood (referred to as 58A-EN) computed with the HEC-2 steady state computer program included the dynamic loop effect. An attempt was made also to identify and to quantify the physical phenomena which generate non-unique stage-discharge relationships.
The Use of Digital Models for Evaluating the Effects of Dewatering in the Tennessee-Tombigbee Divide Cut Area, Mississippi
Year: Authors: Leake S.A.
Modeling techniques are commonly used to simulate local or regional ground-water flow and to aid in the management of ground-water resources. In addition to these applications, the usefulness of digital modeling techniques for engineering and construction purposes is becoming increasingly apparent. Previous solutions to ground-water flow problems were obtained from analytical solutions to flow equations. These solutions were applicable if simplified and idealized aquifer systems and stress conditions were being considered. With digital modeling techniques, however, problems involving more complex geometry and flow characteristics can be solved.
Developing Satisfactory Navigation Conditions at the Approach to Columbus Lock
Year: Authors: Kyzar T.H.
The Tennessee-Tombigbee Waterway project was first authorized in 1946 by the River and Harbor Act. When completed this waterway will link the Tennessee River system with the Gulf coastal regions (Figure 1). It will enable barge traffic to move directly from the Mobile, Alabama area up to the Tennessee River, thereby cutting hundreds of miles off the route now used, which is up the Mississippi and Ohio Rivers and back into the Tennessee River. This waterway will also lessen the heavy barge traffic now using the Mississippi and Ohio. The main justification of the Tenn-Tom project is to reduce transportation cost for transporting commodities from the Gulf coastal areas up to the Tennessee River System. Other benefits will be those pertaining to recreation such as fishing, boating, skiing, swimming, etc.
The Ecology of Endangered Fish in Bayou Pierre
Year: Authors: Teels B.M.
It is the policy of the Soil Conservation Service, a co-operating federal agency in the Bayou Pierre Watershed Project, to avoid any actions which will jeopardize the continued existence of endangered or threatened species listed by the Secretary of the Interior or by the appropriate state agencies. Before any determination of effects of the Bayou Pierre Watershed Project on the bayou or crystal darters could be made, it was necessary that the range and ecology of these two species in Bayou Pierre be more fully understood. To accomplish this it was necessary for the Soil Conservation Service to make a determination of where the darters occur in the Bayou Pierre system to avoid possible destruction of their habitats by watershed measures. Observations were also made on the type of habitat each species requires so that project planning could minimize detrimental effects on both species.
Heat Content of Mississippi Reservoirs
Year: Authors: Schiebe F.R., Ritchie J.C., McHenry J.R.
The heat content of the four northern Mississippi flood control reservoirs; Arkabutla, Sardis, Enid and Grenada was analyzed. Sardis reservoir had the most complete data available, and was analyzed for a l0-yr period. The heat content for reservoirs, whose volumes vary considerably and not very predictably from year-to-year, also fluctuates unpredictably. In this study, it is shown that the heat per unit volume was quite predictable from year to year for a single reservoir and that all the flood control reservoirs in the same region, operated by the same management practices, were also represented quantitatively by the same behavior pattern.
Erosion Measured from a Lister-Till System
Year: Authors: Greer J.D., McGregor K.C., Gurley G.E., Arnold B.R.
Farming the highly erodible sloping soils in North Mississippi by conventional methods has produced a severe erosion problem, which has pointed out the need for new soil conservation practices. To meet this need, experiments were conducted at North Mississippi Branch Experiment Station, Holly Springs, beginning in 1969 to evaluate the effectiveness of no-till and minimum-till systems. The results from the no-till system have already been reported (1). In this paper we present the results of the minimum-till (lister-till) system.
Psysicochemical Conditions of 14 Mississippi Impoundments 1983-1976
Year: Authors: Herring J.
Physicochemical data on small Mississippi impoundments was practically nonexistant prior to the 1970’s. Several investigators have studied the large reservoirs in Mississippi. McGaha (1966) and his students have published numerous papers on the four large flood control reservoirs in north Mississippi. Barkley (197l). McGaha and Knight (1969). and Knight (1972) have published similar works on Ross Barnett Reservoir. Water quality data on small Mississippi impoundments is limited to Grantham’s (1958) study of plankton in a south Mississippi impoundment and a survey of two Game and Fish Commission impoundments near Starkville by Lorio, Teels and Norwood (1972). The Game and Fish Commission initiated a program of upgrading the state lakes in 1972. Cotton and Herring (1972) found 23 Park Comission and Game and Fish Commission Lakes to be free of mercury and pesticide pollution. Basic water quality data was then obtained so that an effective fisheries management program could be undertaken.
Remote Sensing in Sediment Research
Year: Authors: Ritchie J.C., McHenry J.R., Schiebe F.R.
Present techniques for estimating the concentration of suspended sediments in reservoirs involve the collection of discrete samples for laboratory analysis or the in situ measurement of turbidity at discrete locations in the water body. Most of the in situ techniques have been seriously questioned (National Oceanographic Instrument Center, 1974). These techniques are accurate for the discrete site measured but are too expensive to give the synoptic view of the water body that is needed for an accurate assessment of the patterns of suspended sediment distribution in a water body. A new technique for assessing the concentration of suspended sediment in large bodies of water is to use remotely sensed data in the form of aerial photography or aerial imagery. Since 1970, there has been a large increase in the production and availability of aerial photographs and images. LANDSAT 1 and LANDSAT 2 satellites are providing repeated imagery that are available from several governmental agencies. There are many studies on the use of remotely sensed data to evaluate environmental problems. This paper reviews some of the recent studies on the use of remotely sensed data to evaluate the suspended sediment concentration in water bodies.
Potential Effects of Forest Management Practices on Stormflow Practices and Water Quality
Year: Authors: Beasley R.S.
Forest management practices may adversely affect water, sediment, and nutrient yields in areas where permeable soils overlie an impermeable layer on steep slopes. Such sites are sensitive to management activities because they produce rapid subsurface flow on the upper slopes and overland flow near stream channels. Logging, intensive site preparation, or sewage disposal on such areas can alter the normal flow processes and pollute streams. Environmental damage, however, can be minimized if we understand the basic soil-water processes within the forest ecosystem and the potential impact of management practices on flow, and if we can use criteria for evaluating the sensitivity of forest sites to damage.
Bay Springs Lake Water-Quality Study
Year: Authors: Wilhelms S.C.
The objective of the water-quality investigation was to predict the expected temperature and dissolved oxygen (DO) content of the water within and released from Bay Springs Lake. The location of the lock intakes was evaluated with respect to the ability to meet water-quality requirements established by state environmental and wildlife agencies. Physical and mathematical models were used to assist in defining the hydrodynamics and simulate the temperature and DO regimes of the proposed Bay Springs Lake. The effects of lockage rates ranging from 5 to 24 per day for various study years were evaluated.
Surge Effects from Hurrican Eloise
Year: Authors: Burdin W.W.
Hurricane Eloise was the first major storm to directly impact the Panama City beaches since that area started to develop after World War II. (The Panama City beaches is defined as the 18.5 mile reach between Philips Inlet and the Panama City Harbor Entrance.) Because of the recent rapid growth of tourist-oriented facilities, Eloise was the most destructive storm ever experienced there.
The Cost-Output Relationship in Mississippi Water Systems
Year: Authors: Boyet W.E., Hollman K.W., Sterling W.L.
Natural monopolies are typically defined as industries which experience decreasing long-run average costs of production over a wide range of output, enabling the firm to produce sufficient output to supply the entire market at a price covering full cost. Hence, natural monopolies can deliver the product to the consumer at a lower price if they are able to maintain their positions as monopolists than would be the case if competing firms entered the market. Public policy, therefore, tends to discourage or even prevent competition in those industries which are characterized as natural monopolies. The unique characteristic of natural monopolies is the existence of economies of scale. It has often been assumed that this describes the costoutput relationship for most public utilities, including water distribution systems. This underlying assumption has become so widely accepted that it is seldom, if ever, questioned. However, it must be recognized that it may not always be valid even though there are many reasons why one would expect the per-unit cost of delivering water to decline as a particular system’s output is increased. The purpose of this paper is two fold. First, a theoretical explanation of the cost-output relationship for water systems will be presented. Second, preliminary empirically derived estimates of the cost-output relationships for Mississippi’s water systems will be presented.
Community Self-Help River Forecast Procedures
Year: Authors: Fox W.E., Hurst W.L.
Two methods have been developed for furnishing flood warnings for streams where normal procedures are too slow to provide adequate forecasts. One method is the use of self-help river forecast procedures by community representatives. The other method is the use of a flash flood alarm system developed by the National Weather Service. This paper will be primarily concerned with the development and use of self-help river forecast procedures but flash flood alarm systems will also be briefly described. The self-help concept requires the collection of rainfall reports at frequent intervals from the drainage area above the river gage by a community representative. The representative prepares crest stage forecasts from simplified procedures provided by the National Weather Service and is also responsible for providing the forecast to the community agency that warns the public.
Environmental Considerations and Their Impact on Water Resource Development Projects
Year: Authors: Cribbs M.E.
The topic for my discussion today - Environmental Considerations And Their Impact On Water Resource Development Projects - is quite complex, but interesting, and one in which many of us are deeply involved in the everyday activities of our work. My experience in this field has been entirely with the Soil Conservation Service but part of this work has been the direct involvement with personnel of many other federal, state and local agencies. I would like, however, to generally confine my remarks to the impact on Soil Conservation Service projects but, in theory, most points would apply to projects of other agencies. Also, I hope this presentation will create a better understanding of our problems, the laws and pressures under which we operate, and some of our efforts to overcome these problems in planning and installing water resource development projects that are more environmentally SOUlld. These projects, however, must fulfill, as much as possible, the objectives of the local farmers and the sponsors of these projects since their interest and sponsorship forms the basis for our efforts in these type projects.
Commentary on Long Period Sea Waves that Move into Shallow Water
Year: Authors: Priest M.S., Denson K.H.
For engineering purposes, the most important waves are probably those large, long period waves which move from deep water into relatively shallow water, as they progress shoreward. Despite the numerous related research efforts and publications on shoaling and shallow water waves, very questionable interpretations and applications persist. The commentary presented in this paper is directed at questions relating to the wave period and the "orbit" of water particles in transmitting the wave form. Photographic evidence of orbital behavior associated with such waves is presented. As large, long period waves move from deep water into shallow water they undergo a change in form and, ultimately, tend to behave more as individuals than as parts of an oscillatory system. That is, the wave period apparently ceases to be of any real significance in describing the wave behavior. Of the theories which have been considered for describing orbital behavior, and which have been compared with laboratory shallow water waves, it appears that the cnoida1 theory may be the most generally acceptable. However, an orbital behavior that is characteristic of the large, long period waves, for which the period loses significance as the waves move shoreward, remains an open question.
Determination of Water Quality Within and Downstream of Bay Springs Lake
Year: Authors: Wilhelms S.C., Hebron F.L.
The Tennessee-Tombigbee Waterway will be a navigable waterway made up of natural rivers and streams and man-made canals and locks and dams. The waterway is located in Alabama, Mississippi, and Tennessee (Fig. 1). It will extend upstream from Demopolis, Alabama (on the existing Black Warrior-Tombigbee Waterway 217 miles (349 KID) above Mobile, Alabama), via the Tombigbee River to the east fork of the Tombigbee. The project then extends up into Mackey’s Creek, through a deep cut in the Tennessee Divide to Pickwick Lake via Yellow Creek. The waterway joins the Tennessee River system in the Yellow Creek embayment near the common boundary of Mississippi, Tennessee, and Alabama.
Feasibility Report on Gulf Coast Deep Water Port Facilities
Year: Authors: O'Bannon W., L .
The authorization for the U.S. Army Corps of Engineers Gulf Coast Deep Water Port Study stemmed from the rapidly growing practice of using very large ships in the movement of bulk commodities in international trade. This growth has recently been accelerated in the case of crude oil carriers with near-exponential growth taking place in vessel sizes. With the closing of the Suez Canal in 1956, and again in 1967, European nations dependent upon Middle Eastern oil found it economically advantageous to transport crude oil cargoes in increasingly larger supertankers. Tankers up to 700,000 deadweight tonnage (dwt) are under construction, and plans for larger ones are on the drawing boards. Whereas, in 1945 the bulk of the world’s oil was carried by the standard l6,000-dwt T-2 workhorse, today the 200,000300,000- dwt ship has already become world standard for long distance bulk crude oil movement. As the size of vessels increases, so does their draft. The l6,000-dwt T-2 drew 30 feet, and most American harbors were dredged to accommodate that depth and later improved to approximately 40 feet as tanker size increased. But since the quantum jump in tanker size made by the Japanese in the early 1960’s, no East Coast nor Gulf Coast harbor has either the facilities or the natural depths to handle superships which draw up to 94 feet.
Suspended Sediment in Four North Mississippi Reservoirs
Year: Authors: Schiebe F.R., Ritchie J.C., McHenry J.R., May J.
The suspended sediment concentrations at the major inflows and the outflows of four North Mississippi (Arkabutla, Sardis, Enid, and Grenada), reservoirs were measured weekly beginning May., 1973. Sediment concentrations within the four reservoir water bodies were monitored regularly between July 1973 and November 1974. These data are presented and compared with weekly accumulated precipitation on each reservoir’s watershed. For two representative cases, the influence of the total suspended solids on physical reservoir phenomena was analyzed.
The Role of the Corps of Engineers in Coastal Zone Management Planning
Year: Authors: Hildreth J.B.
"The coastal zone is rich in a variety of natural, comnercial, recreational, industrial, and esthetic resources of immediate and potential value to the present and future well-being of the Nation." This statement, which so aptly explains the reason for National concern over the coastal zone, was taken from the Congressional Findings in the Coastal Zone Management Act of 1972 (Public Law 92-583, 92nd Congress, S. 3507, October 27,1972). That Act establishes a National policy to preserve, protect, develop, and where possible, restore or enhance the resources of the coastal zone of the United States. It also provides for monetary assistance to the states to facilitate utilization of coastal zone resources, coupled with adequate protection of the coastal zone environment, through development and implementation of state-wide comprehensive Coastal Zone Management programs. The purpose of this paper is to present the major activities of the Corps of Engineers that may impact on the coastal zone and bear directly on coastal zone management planning. It also presents ways in which the Corps can assist states in the preparation and implementation of coastal zone management plans as called for in the Coastal Zone Management Act of 1972.
Wastewater Stabilization Ponds and PL 92-500 Case Studies and Upgrading
Year: Authors: Tapp J.S.
This paper will report on the ability of the wastewater stabilization pond process to meet the secondary treatment criteria. In addition, case studies of upgrading various wastewater stabilization ponds to meet the secondary treatment criteria will be presented. This information should be of value to those who seek a familiarity with the ability of stabilization ponds to meet the secondary treatment requirements of PL 92-500 and the expected effects of various processes to upgrade stabilization pond treatment. In addition, those involved in the design of systems to upgrade stabilization ponds may be able to draw parallels between the information presented here and their actual situation to arrive at the design of an efficient-low cost system.
Water Resources and the Mississippi Coastal Zone Management Program
Year: Authors: Goldman L.E., Lucas W.C.
A basic recurring thrust of the Coastal Zone Management Act is the federal interest in maintaining and improving the quality of the nation’s waters. As an example, the "coastal zone" of a state is closely attuned and must be defined with the navigable waters of the nation and their tributaries. The water oriented thrust of the Act and the experience gained by the Mississippi Marine Resources Council staff in developing the first year coastal zone program form a good base for considering how water resources are being treated in coastal Mississippi and may provide guidance for statewide land use programs that may eventually come into existence.
Some Virological Aspects of Water Purification
Year: Authors: McCamish J.
The goal, of course, is virus-free water for drinking, for recreation, for shellfish beds. This goal is added to the other goals for the production of high quality water, but many of the procedures already used to produce clear, colorless, odorless, chemically and bacteriologically safe water are useful, even essential, to the elimination of viruses. Since more and more water must be reused it is essential that the elimination process be carried out before waste water is discharged into a water source. It is said that proven outbreaks of water-borne virus disease are extremely rare, and that these rarities can usually be traced to inadequate water treatment. That, in itself, constitutes an argument for adequate wastewater treatment. But there is another, more subtle argument which hinges on a peculiar characteristic of virus infections. One detectable virus particle can infect a human being but many, in some cases most, of the infections with low doses are subclinical. In the infected, apparently healthy host the virus can multiply and be excreted in enormous numbers. The contacts of the original host may be exposed to diseasecausing doses. Or they may in turn develop mild or inapparent infections and transmit the virus to an ever widening circle of contacts. By the time the number of clinical cases becomes excessive, the epidemiological association with water may be obscured.
Hydrologic Digital Simulation - A Water Resources Management Tool
Year: Authors: Vicroy C.E., Cry G.W.
The amount of available water in the state of Mississippi is relatively constant over the long term. Proper use of this valuable resource will ensure a sufficient supply for the use of the citizens of Mississippi for a long period of time. In recent years there have been considerable advances in the science of hydrology. One evidence of this is the use of modern techniques of modeling and, in particular the application of digital modeling, for forecasting the flow of rivers by the National Weather Service. The Lower Mississippi River Forecast Center, located at Slidell, Louisiana is currently employing a modified version of the conceptual digital simulation Stanford Watershed Model to forecast the flow of the rivers in the state of Mississippi. Forecast of the volume of water that will be flowing in the Pascagoula, Pearl, Big Black, and yazoo Rivers in Mississippi is available daily for use by state and municipal authorities to aid them to efficiently utilize the available streamflow.
Mathematical Modeling for Water Quality Management
Year: Authors: Shindala A., Corey M.W., Zitta V.L.
It is estimated that by the year 2000, the population of the United States will reach 300 million people. It is also estimated that to reach a modest level of this nation’s water quality goals will require an expenditure of from 2 to 5 billion dollars per year. To achieve these national water quality objectives in a most effective and economical way will require comprehensive planning and a thorough analysis of the complex alternatives for wastewater management. This need for planning was recognized by the federal regulations regarding construction grants for wastewater collection and treatment systems published July 2, 1970, which states that all such projects must be part of a comprehensive plan in order to be eligible for federal aid. To insure the selection of an optimum plan for wastewater management and to have the means of projecting future needs and identifying long-range plans, comprehensive planning must be based on sound mathematical models. Msthematical models can be utilized to analyze past data, assess present conditons and predict future requirements. Only through the use of mathematical modeling can optimal solutions be obtained to meet the set economic and social constraints.
Economic Impact of Petroleum Refining and Petrochemical Production and the Development Implication of a Deepwater Port Facility
Year: Authors: Garrison R.R.
The existence of a deepwater port facility off the Mississippi/Alabama Coast should result by 1980 in new refining and petrochemical facilities in the area of four 200,000 barrels per day refining units and two 1 billion pound ethylene units (a 1 billion pound ethylene unit is equivalent to a 200,000 barrel per day refining unit in capital investment and labor requirements). This represents a capital investment in 1976 dollars of $2.4 billion and direct employment of 3,600. Estimates on indirect employment varies from 3.5 to 5.5 for each direct employee. This represents $41 million annual direct payrolls using 1973 wage scales--not including indirect employment earnings. If Mississippi obtains location decisions on two 200,000 barrels per day refining units and one 1 billion pounds per year ethylene unit, this would result in Mississippi increases in personal income of $37.4 million, an increase in retail sales of $27.5 million and increase in sales tax revenues of $1.8 million annually in 1980 (based on an R&D Center econometric model). This does not include increases in indirect employment that would be associated with these installations, nor does it include possible satellite developments such as fertilizer, monomers for fibers, plastics and elastomers.
Energy and Environmental Characteristics of Alternative Thermal Electric Generating Plant Cooling Arrangements
Year: Authors: Arnold T.G., Buck, Jr. C.L., Bowers W.L.
Steam electric generating plants are the largest industrial users of water in the world. In 1968 the total water usage for the steam electric generating plants of the United States was approximately 4x1013 gallons. This amount of water is approximately 10% of the total runoff of the nation’s rivers. In the recent past, growth of the steam electric generating industry has occurred at an annual rate of approximately 8%. This growth rate has resulted in doubling the installed capacity for each of the past several decades. The implications which are clearly derived by extrapolating such growth history into the future is a large reason for the present regulatory concern for controlling thermal discharges from electric generating plants. Any exponential growth of a physical system continued far enough into the future will result in an unsatisfactorily large condition. However, it is presently becoming apparent that factors such as shortages and economics will prevent the indefinite doubling of electric generating capacity in the future for each ten year period as has occurred in the recent past. At the time the initial nation wide concern for thermal discharges was becoming clear (perhaps some 6 or 8 years ago),the limited nature of the resource base available for the production of goods and for pollution abatement was not as generally recognized as is the case at present. Also, until very recently, meaningful data on the thermal effects of power generating stations has been lacking. Thus neither the electric generating industry nor the responsible regulatory agencies could estimate accurately the effects of thermal discharges on receiving water bodies. The Environmental Protection Agency has tended to rely on extrapolation of laboratory thermal tolerance experiments in identifying possible detrimental thermal effects and as a consequence has treated the thermal discharge problem in a very conservative manner. The electric generating industry perhaps aided in the establishment of a nation wide urgency in the coining of such terms as "thermal enrichment".
Look, No Clarifier!
Year: Authors: Burgure J.E.
Baxter Wilson Steam Electric Station is located approximately two miles south of Vicksburg on the east bank of the Mississippi River. The plant’s first unit is a 550 megawatt supercritical unit which went into operation December, 1966 and a second unit with a capability of 750 megawatt that went into operation in October, 1971. Condenser cooling is once-through using Mississippi River water. Make up water for boiler, sanitary and other plant uses was from the city of Vicksburg. An evaluation for producing the right quality water by an in-plant water treatment plant or other means was made in 1964; at that time, without taking in consideration other parameters which are the subjects of this paper, the economic evaluation favored the purchase of Vicksburg city water. See Table 1 for evaluation. Availability of ground and surface water was of no concern. The Mississippi River and ground water available in this area are plentiful; however, for our operation, the use of either source meant large investment in water treatment equipment, such as clarifiers plus the possibility of additional personnel for operation and maintenance and with either source, it created a problem with solid waste disposal for the company.
Sediment Yield Estimates Based on Floodwater Measurements and Samples
Year: Authors: Willis J.C., Bowie A.J., Parsons D.A.
This study was conducted on Coles Creek and on the Buffalo River in southwestern Mississippi for which diversion channels will be necessary if proposed levees along the Mississippi River are constructed. A knowledge of the sediment quantities and sizes delivered to the sites by the streams was considered to be desirable. The study was requested and supported by the Soil Conservation Service. A progress report was presented in 1969 by Willis, et al. (1). A data collection program was followed that gave the information needed to estimate average annual sediment yields, using the sedimentrating curve-flow duration method. Noteworthy precedents in the use of this method have been described by Campbell and Bauder (2), Miller (3), and Wark and Keller (4). Bed material sizes, suspended sediment sizes, channel geometries, and water surface elevations in selected channel reaches, and for selected floods, were also measured in order to compare the sediment rating curves derived from flood water sampling with those derived by other techniques.
Monitoring Nutrient Losses from Small Watersheds
Year: Authors: Kilmer V.J., Joyce R.T.
The southeastern United States is a region where fertilizer use and precipitation are relatively high. During 1972, a total of 10.7 million tons of fertilizer materials were used which included 1.4, 0.9, and 1.2 million tons of N, P,O., and K,O, respectively (6). The average annual precipitation ranges between 50-60 inches over most of the region; 40 to 70% of this precipitation is lost as runoff (2, 15). Evapotranspiration normally exceeds precipitation from early spring to early fall over much of the area. These characteristics would appear to favor the transport of native soil and fertilizer nutrients to surface and ground water, particularly during the winter and early spring. However, there is little indication that fertilizer nutrients, particularly N, will accumulate in surface or ground water except where such water remains stagnant or nearly so.
Response of the Lower Mississippi River to Changes in Valley Slope, Sinuosity and Water Temperature
Year: Authors: Robbins L.G.
The problem of trying to maintain trouble-free alluvial waterways is very difficult. The use of our waterways either as floodways or navigation routes has been increasing at a rapid rate which has often resulted in an attempt to alter or control them. Thus, it is imperative to study the variables influencing the channel morphology in order to more effectively design and locate structures which will compliment instead of aggravate the channel form and process. The Potamology Section, Vicksburg District, Corps of Engineers, has been studying the variables influencing the morphology of the Lower Mississippi River. Three of these variables are valley slope, sinuosity and water temperature.
Multiple Outlet Selective Withdrawal Technique for Water Quality Prediction of Lake Releases
Year: Authors: Gloriod T.L.
The demands on multipurpose reservoir planning, design and operation for quality releases have played a significant role in evaluating both existing and planned projects. The desire to meet downstream water quality criteria without diminishing the quantity has necessitated research aimed at the development of techniques useful to the project designer and operator in meeting these downstream goals. One such technique resulting from research studies is selective withdrawal, whereby reservoir outlet ports are located at various levels enabling releases to be taken from one or more of several different strata. Generally, downstream water quality goals center about the temperature of the water. However, thermal phenomena in terms of water quality may bring about differences in the concentration of dissolved oxygen, pH, suspended solids, etc; so much so that thermal stratification in reServoirs can be thought of as quality stratification.
Mathematical Modeling of Water Quality
Year: Authors: Fontane D.G.
Concern with the environment has made it necessary to attempt to assess the "Environmental impact" of proposed water resource projects. Whether the project is a waste discharge into a waterway or a large impoundment, the engineer must try to determine the effect of the project on the physical, chemical, and biological characteristics of the existing water resource system. Generally this determination can best he made through the use of a "model" to represent the existing system. The model can then be modified by the proposed project and the effect observed over space and time.
Environmental Aspects of Watershed Planning
Year: Authors: Sullivan E.G.
The small watershed act, as it was called, was hailed as a boon to conservation, and conservation agencies and organizations anxiously awaited the benefits from this program. All went well through the early years of implementation, but controversies began to arise in the 1960’s. Criticism carne first primarily from game and fish agencies and wildlife organizations. This criticism was aimed primarily at stream channel alteration and drainage of wetlands and the effects of these practices on fish and wildlife habitat. This was first brought to the attention of SCS and the public, in the Southeast, through a resolution passed by the Southeastern Association of Game and Fish Commissioners in 1962. This criticism gained momentum through the 60’s as other environmental groups came on the scene. Some of this criticism was justified. Some mistakes are likely to be made in implementing any new program, and we must recognize that in these early days interdisciplinary planning which would have given equal weight to all resources during the planning process was not always considered. In our American system, when an issue becomes popular and gains momentum, there is often an overkill. This may have occurred in the small watershed program and much of this has come about through a misunderstanding or by acting on insufficient facts. Be that as it may. My emphasis from here on will be that watershed planning today is an entirely new concept. we call environmental planning, and I think a lot of good of it. on the fact This is what will come out
Treatment of Domestic Sewage at Offshort Locations
Year: Authors: Hebert G.G., Bryant R.D.
Until recently, the oil industry had not been confronted with the problem of having to provide sewage treatment facilities on its offshore platforms in the Gulf of Mexico or at its land based operations in the coastal marshes. However, in late 1970, with the advent of Federal regulation and the EPA, the increased activity of the Louisiana Stream Control Commission and the Department of Health in this area, and the issuance of OCS Order No. 8 by the United States Department of the Interior, Geological Survey, Conservation Division, Branch of Oil and Gas Operations, Gulf Coast Region (U.S.G.S.), the necessity for sewage treatment had become readily apparent. In an effort to cope with this new problem, the numerous companies affected began the search for equipment which would be suitable for effecting results in compliance with the standards set. Chevron Oil Company retained Linfield and Hunter, Inc., Consulting Engineers, to assist in the interpretation of the new requirements, to establish criteria, to select equipment, to prepare specifications for the procurement of equipment, and to assist in the preparation of approval requests to the regulatory agency having jurisdiction over the location to be provided with treatment facilities.
Nitrogen, Phosphorus, and Other Chemicals in Sediments From Reservoirs in North Mississippi
Year: Authors: McHenry J.R., Ritchie J.C., Gill A.C.
Much interest and concern has developed in recent years concerning the pollution of the environment due to man’s activities. This concern has included a controversy over the role that agricultural chemicals play in the pollution of natural waters. Water quality is affected by the characteristics of both the dissolved and suspended materials in the water (4)3/. Sediment produced from soil erosion has been called the major pollutant of surface waters in terms of absolute mass (1). Chemical pollutants from agricultural, commercial, industrial, and domestic sources are associated with the sediments from soil erosion. The role that agricultural fertilizers play in the pollution of natural waters concerns both the agriculturist and the general public (3). The capacity of lake or reservoir sediments to adsorb or exchange various elements or compounds from all input sources influences the concentration of these chemicals in the overlying waters (8). Sediment samples were collected in 1969-72 from a number of reservoirs and lakes, and surface soil samples were collected from the contributing watersheds. The results of chemical analyses on samples collected in north Mississippi are presented and discussed in this report. The purpose of this study is to relate the chemical loading of these sediments with their origin and to the stresses placed on the system by man’s activities.
The Application of Remote Sensing Techniques for Data Collection on the Mississippi River
Year: Authors: Harris P.C.
Effective river management and control requires the constant surveillance and analysis of the natural and man made effects both in and near the main channel. Present day surveying techniques are too costly and time consuming to gather necessary data in a river during a particular flow condition. In order to determine if a remote sensing system may offer a means of replacing or enhancing our data collection, the Vicksburg District has a contract with Colorado State University on the investigation of remote sensing equipment and techniques to obtain data from the Mississippi River. The interpretation of the data is being done independantly by Colorado State University and the Potamology Section of the Vicksburg District. Remote sensing is defined as a procedure for obtaining information about an object without actually being in physical contact with the object. The remote sensing systems used for this study are readily available, relatively inexpensive and are intended to function specifically as an operational package for enhancing data collection. The remote sensing instrumentation used was mounted in a medium twin engine aircraft and flown at conventional altitudes and air speeds. The multi-remote-sensor package affords the opportunity for simultaneously recording the reflected and emitted electro-magnetic energy in several portions of the spectrum.
Commentary on Similitude for Turbulent Liquid Flow in Pipes
Year: Authors: Priest M.S.
The use of physical models for the study of fluid flow is a venerable procedure. In fact, it appears that there is a school of thought which considers the use of physical models as old-fashioned and favors mathematical models. Each approach has its place. When there is sufficient knowledge of a particular problem to warrant a mathematical model, it should be used. However, the physical model has proven to be a very informative tool. Perhaps the following remarks will contribute something to both approaches. Although a superficial consideration of turbulent liquid flow in pipes may lead the unwary into believing that similitude of two or more systems is a simple matter, which it may be, this problem seems to have been shrouded in confusion for a surprising number of investigators. The only difficulty that might be anticipated in achieving geometric similarity would be practical difficulty in satisfying a requirement that the relative boundary roughness (for pipes of circular crosssection: ratio of height of roughness to diameter or radius of pipe) have the same numerical value in all systems, when the value of relative roughness is small enough to make construction difficult but not so small that a "smooth" boundary can reasonably be used. The requirements for dynamic similarity of systems have been a common source of confusion.
The Pearl River Basin - Its Plan and Potential for Development
Year: Authors: Cribbs M.E.
The Pearl River Comprehensive Basin Study is part of the national comprehensive river basin planning program that has developed from recommendations in the 1961 report of the Senate Select Committee on National Water Resources and subsequent action of the Executive Branch and the Congress. The basic objective of this program is to plan for the best use, or combination of uses, of water and related land resources to meet all foreseeable short- and long-term needs. The study has been directed toward developing an understanding of the existing and future needs of the Pearl River Basin; providing a sound basis for, and recommendation of, an early-action program of measures that should be undertaken within the next 10 to 15 years; and establishing a framework for future planning for the basin. It has been conducted as a coordinated State-Federal interagency study.
Laboratory Studies of the Erodibility of Cohesive Materials
Year: Authors: Grissinger E.H.
Research Needs Statement C3-9 of the Highway Research Board (2)2/ is "Research on the Effect of Physico-Chemical Factors on the Erosion of Soil." The Problem Area of this statement concludes with, "Further, there exists at present no engineering test which is universally acceptable and which can be used to predict the erodibility of soils in the field." Part of this problem originates in the complex process of the erosion of cohesive materials. This paper is a progress report concerned with one specific segment of this problem, i.e., the influence of time and water content variables on the erodibility of cohesive materials.
Water Quality Aspects of Reservoir Operation
Year: Authors: Bohan J.P.
The recent attacks on pollution and the desire for enhancement of the quality of our water resources has increased the demands on multipurpose reservoir operation. In addition to maintaining a mass budget, we must now budget the water quality in order to satisfy the ever increasing downstream quality demands. In order to do this, we must be able to measure or predict the thermal and chemical quality of the impounded water and then be able to predict the quality of the water withdrawn from the reservoir. Careful planning, design, and operation are required in order to satisfy the multiple and often conflicting requirements. Several techniques to improve the quality of reservoir releases have been investigated. These include selective withdrawal through an orifice or over a submerged weir, partial or complete mixing of the reservoir, injection of air and pure oxygen through penstocks, turbines, draft tubes or tailraces and controlled operation of hydraulic structures to regulate gas transfer processes. Before these techniques can be applied, we must know or be able to predict the water quality in the reservoir. This requires a knowledge of the physical processes involved in the development and decay of thermal stratification in a reservoir as well as the chemical and biological consequences of stratification. This paper will attempt to briefly describe some of these processes and consequences and to explain some of the techniques available to achieve water quality improvements in and downstream of reservoirs.
Field Performance and Evaluation of Two Automatic Suspended Sediment Pumping Samplers
Year: Authors: Murphree C.E., McDowell L.L., Bolton G.C., Bowie A.J.
Numerous methods and types of samplers have been used to deter-3/ mine amounts of sediment being transported in flowing streams (3,4).Depth integration of several verticals in a stream cross section is probably the most accurate method of determining the mean suspended sediment concentration, but this method is costly, time consuming and requires numerous personnel when a network of watersheds is being studied. To meet the needs for accurate and extensive measurements of suspended sediments in streamflow, various sampling and monitoring devices have been developed to supplement or replace manual sampling methods.
Impact of Recreation on Water Resource Management
Year: Authors: Cartee C.P., Williams, Jr. D.C.
The importance and impact of recreation in the planning, development, and use of water resource projects is an easily recognizable factor today. In fact, it would be rare under existing planning functions if recreational potentials were not consciously recognized and incorporated into most water related project developments. This trend in part no doubt stems from the public’s tncreased demands for water recreational facilities resulting from released hours avatlable for leisure. Moreover, as the demands of a complex society become even greater, it can be surmised that ever increasing escape mechanisms will be requested, water recreation being one of many such outlets. These forces have produced some unique ramifications for the agencies involved in water resource planning, development, and management. With the injection of water recreation under agency umbrellas, it has put an additional stress on existing organizational mechanisms. Agencies have responded to this enlarged need differently, which in turn has resulted in variegated management and operation frameworks. This paper is purposed with providing a sequential analysis of the development of water recreation facilities in the State, identifying the major agencies involved, indicating their response to water recreation in terms of planning, development and management, and suggesting alternative approaches to deal with some of the resulting problems.
Impact of Recent Laws and Regulations on Water Resources
Year: Authors: Larson D.E.
There have been several laws enacted in the last few years that are significantly affecting our water resources and the planning for water resource developnent. Depending on the viewpoint, some will consider these laws as having adverse effects, while others will consider them in a favorable light. My experience has been for the most part in river basin planning, so I will confine most of my remarks to the laws and regulations that affect the planning process, and point out a few new laws on a state or local level that affect water resources more directly.
Representations of Rainfall and Runoff by the Descending Exponential
Year: Authors: Parsons D.A.
Many applications to rainfall and runoff data have shown the general satisfactoriness of the descending Exponential Function to represent the distributions of magnitude of these things. Specifically included are point rainfall amounts in given time periods up to a week or more, depending upon the frequency of occurrence, point rainfall amounts in storms, peak flood flows, flood volumes, and runoff amounts in given time periods. Schafmayer and Grant (1) used the Exponential Function for Chicago rainfall. Accepting this function as representative of the distribution in magnitude of single events, other functions can be derived therefrom that represent the largest event in groups of successive events from the exponentially distributed values. Also, still other functions can be derived that express the distributions of the means and sums of the magnitudes of groups of successive events from a population with an exponential distribution.
Recent Developments in Water Pollution Control Legislation
Year: Authors: Traina P.J.
In 1961 the Law was amended to strengthen the enforcement provisions, increase the municipal waste treatInent grants, authorize the preparation of comprehensive river basin plans, and authorize a large scale re search and development program. In 1965 and 1966, further amendments to the Law called for the establishment of water quality standards by the States, again increased the municipal treatment grants, expanded the research and development activities, and authorized grants to local and State agencies for water quality management planning. In 1970, the Act was again amended to incluae Federal responsibilities in oil and hazardous materials pollution, vessel pollution, acid mine drainage, and directed all Federal agencies to ensure compliance with water quality standards of all their facilities which they fund or license. While there have been a number of amendments to the 1956 Act, the Law has basically remained the same. Its purpose has been to enhance the quality and value of the water resource. Its strategy has been to allow the States to take primary responsibility with Federal technical and financial support, and its scope has been limited to interstate waters and municipal and, to a degree, industrial point source discharges. Within the past few months both the Senate and the House have passed legislation which would completely change the thrust and scope of the Federal water pollution control program. I would like to address the rest of my remarks to what those changes are and how they will affect the Federal program.
Hydrologic Performance of Eroded Lands Stabilized with Pine
Year: Authors: Ursic S.J., Duffy P.D.
Southern pines, particularly loblolly, are ideal for erosion control, and millions have been planted on the middle and upper southern Coastal Plains to heal and restore the productivity of abused and abandoned lands. Earlier research in northern Mississippi indicated that such plantings reduced sediment production to insignificant amounts and perhaps reduced runoff. In this paper we examine the runoff and sediment yield characteristics of eight small, pine-covered watersheds with a wide range of soil and antecedent erosion conditions. The results demonstrate the importance uf soil information for predicting hydrologic behavior and show that average annual water and sediment yields can be satisfactorily predicted from annual precipitation and soil survey information. We discuss the efficiency of pine plantings in controlling flood flows and sediment yields, and we point out possibilities for managing the plantations to increase groundwater recharge.
Evaualtion of Stone Dyke Systems and Their Locations on the Lower Mississippi
Year: Authors: Walters, Jr. W.H.
The object of dikes, when used for the benefit of navigation, is to modif’y the flow by using transverse structures for channel contraction or the reduction of flow in a secondary channel and guide vanes for directing the flow. Dike systems are very rarely used to control or influence high water flow for the sake of navigation, since depths are more than sufficient. It is only during low water that shoals or channel irregularities begin to present obstructions. The purpose of the study is an attempt to evaluate stone dike systems with respect to their various locations and designs using as a parameter the frequency of structural damage or failures. These are localized or random losses of stone which threaten the structural integrity and/or the performance of a dike system. The fact that a particular dike does encounter damage does not always mean that the system as a whole has failed in its intended purpose. This type of risk is inherent in all mounded stone structures constructed in flowing water. This study will endeavor to gain some insight into any trends in failure occurrences and to eliminate some of the conjecture involved in dike system layout and design.
Variations in Runoff and Sediment Yields of Two Adjacent Watersheds as Influenced by Hydrologic and Physical Characteristics
Year: Authors: Bowie A.J., Bolton G.C.
Many hydrologic models have been developed during recent years in an attempt to describe the various flow processes. Many of the models have been designed to include several degrees of freedom that can be manipulated to produce a correct mathematical answer when applied to historical data. Often, however, the watershed parameters must vary between unreasonable limits for these models to fit observed data closely. This manipulation implies that a model is being used outside the range of conditions for which its basic assumptions are valid or that it is based on incorrect assumptions altogether. Unfortunately, because measurements of all the relevant parameters are either inadequate or nonexistent, very few actual field tests have been made to determine the range of applicability of most of these models. Only intensive field study can determine the limitations that must be imposed or actual range of values assigned to various parameters. However, if the hydrologic studies conducted in a research watershed are to provide useful results, the findings must be quantitatively transferable to similar watersheds. To do this, the relationships of watershed physical characteristics and land use to water resource must be established. Only when these watershed characteristics are included in the relationships will it be possible to reconcile such diverse findings as to the difference in runoff and sediment yields of two adjacent watersheds, when for all apparent purposes the two watersheds are almost identical. The purpose of this report is to examine two such watersheds and evaluate certain known parameters that influence runoff and sediment yields.
Practical Guidance for Estimating and Controlling Erosion at Culvert Outlets
Year: Authors: Fletcher B.P., Grace, Jr. J.L.
This paper summarizes the results of research conducted at the U. S. Army Engineer Waterways Experiment Station (WES) during the past nine years to develop practical guidance for estimating and controlling erosion downstream of culvert and storm-drain outlets. Initial efforts were concerned with investigation and development of means of estimating the extent of scour to be anticipated downstream of outlets. Subsequent efforts have involved investigation and evaluation of various schemes of protection for controlling erosion such as horizontal blankets of rock riprap, preformed scour holes lined with rock riprap and channel expansions lined with natural and artificial revetments. In addition, efforts have been made to determine the limiting discharges for various energy dissipators including simple flared outlet transitions, stilling wells, U. S. Bureau of Reclamation type VI basins and St. Anthony Falls stilling basins. Empirical equations and charts are presented for estimating the extent of localiz..d scour to be anticipated downstream of culvert and storm-drain outlets, the size and extent of various natural and artificial type revetments and the maximum recommended discharge for each type of energy dissipator investigated. With these results, designers can estimate the extent of scour to be expected and select appropriate and alternative schemes of protection for controlling erosion downstream of culverts and storm-drain outlets.
Economic Determinants for Sediment Management on a North Mississippi Watershed
Year: Authors: Cooper H.R.
Fluvial sediment and its many ramifications are of tremendous economic significance to our national economy. Annual damages in the United States from sediment and sediment related problems have been estimated at more than 500 million dollars. Sediment, which is the end product of soil erosion as well as the geological process, may be defined as out-of-place soil material from a previously designated location. Damage occurs in many forms. Sediment can plug channels, which creates or intensifies flooding. Infertile sediment deposited on fertile land reduces productivity of that land. Sediment deposited in reservoirs decreases the storage capacity needed for water supply and flood control. Increased turbidity of streams and rivers caused by sediment endangers fish and wildlife. Additional processing of sediment laden-water is necessary if that water is to be used for municipal or industrial purposes. Many other examples of sediment damage could be cited. Because of this trememdous damage from sediment the powerful forces that influence sediment production should be efficiently managed.
Restoration of the Mississippi State Port at Gulfport
Year: Authors: Williams J.V.
On the morning of Monday, August 18, 1969, Port Officials inspected the catastrophic damage to the Mississippi State Port at Gulfport. The port facilitie s were in an almost unbelieveable state of destruction in the wake of Hurricane Camille, the worst storm of record ever to hit the United States Mainland. The Officials, representing the State Port Authority, responsible for Port Operations and the Mississippi Agricultural and Industrial Board, owners of the Port with overall responsibility for Port matters, faced a rebuilding program which ultimately cost nearly six million dollars. Restoration and reconstruction were accomplished in three general phases; namely (I) immediate emergency clean-up, (2) emergency repairs to the banana terminal and (3) conventional contract procedures whereby plans and specifications were prepared by various firms and bids taken in the normal manner for construction and repair contracts. This paper deals primarily with the third phase of work and more particularly within the limits of the West Pier. Other phases and areas are touched on briefly.
Water Resources Problems and Opportunities Associated with Multi-Purpose Impoundments
Year: Authors: Burt J.P.
The increase in population and leisure time in the United states has created substantial demands on the available surface water resources. People want nearby areas to participate in the water contact sports; large population centers need more water to meet the requirements of the homes and industry; more irrigation water is needed to meet the increased demand of food; and often, flow augmentation is necessary during low stream flows to help similate the waste discharge from industry and municipalities. These various water-use needs have created pressure on the different state and federal agencies involved with developing water resources to incorporate numerous purposes in the water development projects, i.e. multiple-purpose impoundments as an example.
Chlorinated Hydrocarbon Insecticide Contamination of Streambed Sediments in the Mississippi River Delta
Year: Authors: McDowell L.L., Grissinger E.H., Bolton G.C., Parsons D.A., Barthel W.F., Hawthorne J.C., Ford J.H.
The large amounts of chlorinated hydrocarbon insecticides previously applied to crops in the Mississippi River Delta have not created widespread, chronic contamination of the streambed sediments in the Mlississippi River (detectable at 0.05 ppm) and its major tributaries (detectable at 0.01 ppm). On the tributaries, with one exception, DDT analogs and metabolites were the only residues originating from agricultural or urban sources. Significant contamination resulted from manufacturing operations in the Wolf River-Cypress Creek complex at Memphis, Tenn., and from a group of pesticide formulating plants in Mississippi. Concentrations of individual pesticides ranged from nondetectable to 24,000 ppm.
Nutrients and Algal Removal from Oxidation Ponds Effluents
Year: Authors: Shindala A.
Waste stabilization ponds have been used effectively to treat domestic and many types of industrial wastewaters throughout the United States. The low cost of construction and operation has resulted in their wide adoption by municipalities and industries as a means of wastewater treatment. It is generally recognized that, when properly designed, stabilization ponds will eventually become populated with suitable bacteria and algae. Bacteria will oxidize the organic matter while algae, through the process of photosynthesis, supply the oxygen needed for the aerobic bacterial action. A cyclic process is therefore, established in which unstable organic matter is converted to stable cell material.
Reconstruction of the Gulfport Banana Terminal
Year: Authors: Hunter, Jr. D.A.
Destruction of the Gulfport Banana Terminal on August 17, 1969, was substantial and an event of significant economic importance to the residents of Gulfport, the State, and Standard Fruit and Steamship Company. A modern banana terminal is a highly specialized facility generally suited only to the handling of boxed, perishable fruits such as bananas, pineapples and plantains. A four hatch refrigerated ship containing 140,000 forty pound boxes of such fruit can normally be unloaded in less than ten hours - an average discharge rate of 280 tons per hour or 70 tons per hatch per hour. Normal break bulk general cargo discharges utilizing pallet boards and ships gear operate at a rate of 15-25 tons per hatch per hour. The discharge efficiency of a specialized banana facility such as the Gulfport Terminal is thus two to three times that of a conventional general cargo operation. However instead of a conventional 16-20 man cargo gang per hatch, the banana discharge utilizes about 30 men.
Establishment of an Automatic Water Quality Surveillance Program
Year: Authors: McClure, IV N.D.
The impact any action may have upon the environment is a consideration that is receiving more interest and study than ever before. The protection and enhancement of the environment is a matter of self preservation. In order to make perceptive determinations concerning this vital matter, the decision maker must have certain essential facts available to him. The quality of the water that will be released from a hydraulic structure is one of these essential facts. In an attempt to obtain information about the effect existing prototypes in the Mobile District have on water quality, an Automatic Water Quality Surveillance Program was developed. The basic component of this program is the continuous water quality monitor. Basically, as used here, a water quality monitor continuously analyzes water for certain parameters producing an electrical signal proportional to the parametric value and displays and/or records the results in an intelligible manner. An example is to measure the water temperature with a thermistor, display the findings on a dial in degrees centigrade and record the values on a strip chart. The purpose of this paper is to provide a general overview of the establishment of a surveillance program utilizing water quality monitors and enumerate some of the pitfalls. Technical discussions of individual components of the monitor system will be avoided.
Effects of Turbidity on Forest Recreation Potentials
Year: Authors: Lentz R.J.
With increased pressures from our changing social way of life, and requirements for recreation activities as a means of escape, we as environmentalists are receiving increased demands on our waters for quality recreation experiences. New imaginative and creative approaches to recreation programs on our waterways are essential to the survival of a healthy society. The 4 day 40-hour work week, soon to be a reality, will create a vast recreation impact. Ninety firms in the U. S. have already adopted the 4 day system. The Chrysler Corporation and the United Auto Workers have agreed to study the possibility of putting some or all of their 157,000 U. S. employees on a 4 day routine (1). This movement could create a trend thrusting tremendous demands on our already crowded recreation sites.
Water Management Implications of the South’s Third Forest
Year: Authors: Miller W.F., Bhullar H.S.
The South’s Third Forest, which will occupy the land during the years 1969 to 2000, will not be a biologically separate entity from the Second Forest (1945-1968) although it will have distinctive characteristics (28).* These characteristics, based primarily on projections of growth and drain of wood fiber, will have a profound influence upon the Third Forest’s production of other commodities: recreation, wildlife, and water. Current projections of the per capita consumption of paper and paper board far exceed earlier estimates; the current projection for 1980 is 728 pounds compared with the 575 pounds per capita predicted in 1965 (28). The startling aspect is that of the anticipated national needs for the year 2000 the South will be expected to produce approximately 65% - 112 million cords of the 172 million cords. This increased demand would cause the South to increase the annual total cut 2.3 times with pulpwood showing a three-fold increase over the 1968 cut. Unfortunately, this increase must be achieved in the face of a steadily shrinking land base. A net decrease of 10 million acres or five percent of the present forest area is anticipated by the year 2000. Major causes of withdrawal wilI be for agriculture, urban expansion, rights-of-way, impoundments, and recreational areas. The area of greatest loss wiII undoubtedly be in our hardwood resource. For example, in the past 10 years in Mississippi, we have lost to agriculture approximately 1/2 million acres of bottomland hardwoods in the Delta. Also withdrawn from the hardwood resource is the land, in the Barnett Reservoir, and in the future there may be withdrawals amounting to many more thousands of acres in the Tennessee-Tombigbee and the Pat Harrison Waterways in addition to numerous other proposed projects (18). Resource management is further complicated by apparent inconsistencies in Federal programs. Some programs subsidize forest establishment whiIe others are reducing forest acreage through payments for drainage, water control, and reservoir development.
Geometric Stability Analysis of an Alluvial River
Year: Authors: Winkley B.R., Robbins L.G.
The subject of fluvial hydraulics in an alluvial river is a very difficult one because every variable is constantly changing at each place in space and at each point in time. Many empirical equations have been written and these become exponentially more complicated as each additional variable is considered. Any river is a complicated interrelationship of these many variables, and the river engineer is at a loss to recognize all of the variables and to know what degree of dependence to place on each of them.
Opportunities for Recreational Developments in the Private Sector in Mississippi
Year: Authors: Yeates G.W.
Opportunities for the development of significant outdoor recreation areas in the private sector are numerous in Mississippi. These opportunities are significant and substantial in both quantity and quality - in short, they are real. Perhaps you have heard this sort of statement before, or one very much like it, by individuals extolling the virtues of a particular area or the entire recreation field. So have I. But the ones I have heard have usually been broad statements, generalizations. In contrast, I believe I can document my statement to an extent sufficient to convince you there are a large number and variety of specific opportunities. I assume by the title of this conference and the identification of the principal sponsor, you are primarily interested in the relation of water areas to recreation development. However, while most outdoor recreation areas in Mississippi are water-dependent or water-enhanced, there are also some important activities which are not and I will include these in my remarks.
Hurricane Camille Activities of the U.S. Geological Survey in Mississippi
Year: Authors: Hudson J.W.
On November 10, 1969, 12 weeks after Hurricane Camille hit the Mississippi gulf coast the U.S. Geological Survey made public distribution of 14 Hydrologic Atlases showing highwater elevations and the area inundated by the floodwater accompanying the hurricane. These atlases are the culmination of effort that began within 12 hours after the hurricane came ashore in the Bay St. Louis-Pass Christian area. Excluding printing, the cost of the atlases was about $14,000. Behind the Geological Survey’s effort to get this information to the public as quickly as possible was the realization that any realistic and effective settlement of insurance claims and the plans for rebuilding in the devastated area would require the delineation of land area flooded. Through close cooperation at all levels, the Survey was able to produce in three months a series of maps that normally requires one to two years to complete.
The Use of Fallout Cesium-137 as a Tracer of Sediment Movement and Deposition
Year: Authors: Ritchie J.C., McHenry J.R., Gill A.C., Hawks P.H.
The origin and movement of sediment may be determined by identifying certain sediment particles as being specifically associated with a given area and by following the movement of "tagged" sediment particles. These "tracer" particles may be naturally occurring or they may be artificially introduced into the system. The ideal tracer is one which [1) moves, or has moved, exactly as the population as a whole and which (2) is identified readily and its concentration determined. Dyes and radioactivity have been used to tag sediment particles and to follow their movement. The mineralogical and radiological identification of particles also can be used to determine the origins of various sediments.
Interference in the Determination of Sodium, Potassium, Calcium, and Magnesium in Natural Waters by Atomic Absorption Photospectrometry
Year: Authors: McDowell L.L., Ryan M.E.
Atomic absorption is a sensitive and rapid method for measuring sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) in rainfall, runoff and impounded waters. The technique is relatively simple because little sample preparation is required. Much of the early literature on atomic absorption emphasized the simplicity of the method and its freedom from interferences. It is now generally recognized, however, that certain interferences do exist. Recently, Pickett and Koirtyohann (15) 1/, Slavin (20), and Angino and Billings (3) discussed the various types of interference (chemical; spectral, including molecular absorption; and ionization) and their relative significance in atomic absorption.
Temperatures and Hurrican Frequency
Year: Authors: Priest M.S.
Prior to the Atlantic-Gulf "hurricane season" of 1968, there was a widely published news release which indicated the probability of an abnormally large number of hurricanes during that year. Actually, there were fewer than normal. Whatever the basis for the forecast may have been, there was some evident need for revision. Although meteorology is certainly not the forte of this writer, the inaccuracy of the forecast did arouse his interest and curiosity to the extent that he has devoted a little thought to the matter of hurricane frequency. In view of the seasonal nature of hurricanes, there seems to be little doubt as to the role of temperatures or differences in temperatures in determining hurricane occurrence. Consequently, it seems that the development of a frequency forecasting procedure should start with a study of temperatures. If this approach is taken, the immediate question becomes that of identifying the temperatures which are significant to the study.
The Fifth Seacoast - A New Dimension in Transportation
Year: Authors: Barschdorf M.
From the days of the wagon and the raft to todays more sophisticated means of diesel powered towboats pushing whole fleets of barges, high speed mile long trains, and jumbo truck trailers, we continue to funnel the products of our assembly-line, computer controlled factories and farms to the coastal ports for transhipment. Foreign products, in turn, brought into these same coastal ports are distributed by similar means back to the interior markets. Not-with-standing these tremendous twentieth century advancements in the movement of cargo, it is sad to observe that there has been little or no improvement in the related policies and procedures governing documentation and rate making which continue to operate as conceived in the days of the wagon and the raft.
The Role of TVA Reservoirs in Reducing Flood Crests on the Lower Ohio and Mississippi Rivers
Year: Authors: Tucker R.L.
The closure of Kentucky Dam in August 1944 forged the most effective link in the TVA chain of flood control projects to aid in controlling floods on the lower Ohio and Mississippi Rivers. Since that time Kentucky Dam, assisted by the other projects in the TVA system, has reduced the crest of over 50 floods on the lower Ohio and Mississippi Rivers and has prevented direct flood damages totaling over $43,000,000. Table I shows the significant floods on the lower Ohio and Mississippi Rivers since closure of Kentucky Dam, the amount of crest reduction by TVA regulation, and estimates of dollar value of damages prevented by these operations.
Control of Scour at Hydraulic Structures
Year: Authors: Murphy T.E.
Much work has been d.one on the development of energy dissipators for out falls from hydraulic structures, and many good designs have been developed. However, whether for use with structures ranging from relatively small drainage culverts to major spillways, in none of these designs is it contemplated that all of the excess energy of the efflux will be destroyed within the dissipator. This is proper since a structure which provided complete dissipation would be excessively costly and thus a poor design. Seldom does a designer ignore the fact that secondary dissipation outside of the structure itself is necessary but also seldom is due consideration given methods for accomplishing this. Common practice is to provide a nice trapezoidal channel with bottom elevation the same, or even in some cases higher, than the top of the end sill and with bottom width the same as the energy dissipator, and then attempt to stabilize this channel with riprap. Although large size and thus costly rock is used in the area immediately below the dissipator, it is here that a great number of failures occur and costly maintenance is required to prevent damage to the structure or adjacent installations.
Some Considerations for Water Quality and Environmental Protection in Wild and Scenic River Development
Year: Authors: Bacon D.D.
The Wild and Scenic River Act became Public Law 90-542 on October 2, 1968. This Act states in part, "It is hereby declared to be the policy of the United States that certain selected rivers of the Nation which, with their immediate environments, possess outstandingly remarkable scenic, recreational, geologic, fish and wildlife, historic, cultural, or other similar values, shall be preserved in free-flowing condition, and that they and their immediate environments shall be protected for the benefit and enjoyment of future generations (1)." Several Wild and Scenic rivers were designated in the Act for immediate establishment. Others, and the Chattooga is in this group, were designated as candidates for Wild and Scenic rivers. In order to prove themselves worthy, these designated rivers are subject to many types of evaluations. Among the evaluations, water quality is an essential criteria. In fact, river segments designated "wild" are "those rivers or sections of rivers that are free of impoundments and generally inaccessible except by trail, with watersheds or shorelines essentially primitive and waters unpolluted. These are vestiges of primitive America (1)."
Relationship Between Pollution Indicator Organisms and the Salinity of Mississippi’s Estuarine Waters
Year: Authors: Cook D.W., Childers G.W.
The estuarine waters of the Mississippi Sound are probably Mississippi s most important water resource. Seven of the ten most valuable kinds of commercial fish and shellfish are dependent on the estuary for important parts of their life (McHugh, 1968). Five of these seven species, are found in great abundance in the Mississippi estuary. These are the shrimp, oysters, crabs, menhaden and flounders. The 1968 landings of these five species in Mississippi alone amounted to over 165 million pounds with a wholesale value in excess of seven million dollars (USDI, 1968). Yet, most people see the estuary as nothing more than a lot of brown muddy water often considered not fit to swim in and a bunch of "good for nothing" marsh grass full of mosquitos and gnats. Occasionally, they enjoy fishing there but most people want to go offshore into the blue waters to catch the big fish. They never realize that the big fish utilize many of the non-commercial estuarine dependent species as a main source of food.
MIADS - A New Tool in Water Resources Management
Year: Authors: Dissmeyer G.E.
In River Basin and PL 566 watershed planning, we are rapidly moving from an era of generalization into a new era of quantification. We are moving into quantification because today’s problems can no longer be solved with generalized evaluations or planning. Today’s problems are complex, and require intensive inventories, sound analyses, accurate projections and intensive planning for their solution. MlADS is an important new tool which is aiding us in solving today’s problems in water resource management. MIADS is an acronym for Map Infonnation Assembly and Display System developed by Elliot L. Amidon. 1/ We are using this system in the inventory, analysis, projection and planning phases of our work.
Flood Insurance Studies
Year: Authors: Sumrall, Jr. C.L.
The National Flood Insurance Act of 1968 authorized a flood insurance program by means of which flood insurance, over a period of years, can be made available on a nationwide basis through the cooperative efforts of the Federal Government and the private insurance industry. The Secretary of Housing and Urban Development administers the flood insurance program through the newly established Federal Insurance Administration. The act requires that States and local governments also contribute by adopting and enforcing land use provisions so as to restrict future development of lands in flood-prone areas. Why is the Government involved in the flood insurance program? Congress found that (1) many factors have made it uneconomic for the private insurance industry alone to make flood insurance available to those in need of such protection on reasonable terms and conditions; but (2) a program of flood insurance with large scale participation of the Federal Government and carried out to the maximum extent practicable by the private insurance industry is feasible and can be initiated.
The Future of Irrigation in the Texas High Plains
Year: Authors: Wells D.M.
Irrigation in the Texas High Plains has a very uncertain future. Unless a means can be found to supplement declining groundwater supplies, irrigated agriculture in the High Plains will shortly start a decline that will end in oblivion in less than a century. Best current estimates are that peak production from irrigated agriculture will be reached in about a decade, although the peak has long since passed in the southernmost portion of the area. Irrigation is a mainstay of the High Plains economy, but it is not essential to the practice of agriculture. Indeed, a prosperous agricultural economy developed in the period from about 1900 to about the late 1930’s without irrigation, and more than half the cultivated land on the High Plains is still farmed on a dryland basis. Hence, while the decline of irrigated agriculture that will inevitably result from a failure to provide a supplemental source of imported water to the High Plains will result in a decline of net income to farm operators and managers, this decline will not be great enough to put any but marginal operators out of business. Of far greater significance will be the decline of secondary and tertiary benefits to other sectors of the economy. Secondary and tertiary benefits associated with irrigation have been estimated to range from about four times the primary benefits in a dry year to about seven times the primary benefits in a reasonably wet year.(1)
CENTROPORT U.S.A. - A Long Range Plan for Development of the Port of New Orleans
Year: Authors: Lewis W.H.
CENTROPORT is a bold new name for Louisiana’s world port at New Orleans. The central port for mid-continent U.S.A. and the western hemisphere. Destined to become the central port for world trade in the 21st century. The Port of New Orleans today is a major world port handling diverse foreign trade cargo which in 1969 was valued at over $2.6 billion. Total waterborne commerce in the Port, and its environs included in the statistical reporting area of the Corps of Engineers, during 1968 amounted to 113,511,000 tons. Cargo handled over the public facilities of the Port in fiscal year 1968-69 amounted to over 19 million tons, of which about 6 million was high-valued general cargo.
Sampling and Analysis of Coarse Riverbed Sediments
Year: Authors: Muir T.C.
Recent publications from New Zealand (1)1/, the USSR (2) and Canada (3) have stressed the worldwide importance of the systematic collection and presentation of data on natural river processes. One of the problems mentioned in these publications is the difficulty of sampling and analysing coarse riverbed sediments. This problem was encountered in recent studies of bedload transport in the gravelbedded River Tyne in northeast England. During these studies existing sampling procedures were reviewed and some tests were carried out which, supplemented with data from McIvor Creek, Mississippi and combined with the experience of previous investigators, enable a convenient standard procedure for the sampling and analysis of coarse sediment to be suggested. Basically there are two methods of sampling coarse sediment:volumetric (bulk) sampling and areal (surface) sampling.
Euthophication - Causes and Control
Year: Authors: Shindala A.
In recent years, increasing concern has been expressed regarding nutrients in surface waters. This concern, by both the water resource management people and the general public, has been due mainly to the increasing problem of eutrophication of surface waters throughout the United States. Eutrophication has been defined as the process of enrichment with nutrients. This is to say that the aquatic life in a body of water become so fertilized with the nutrient content of its water that productivity Commences at a much faster rate than their decay. The result is the frequent appearance of algal blooms on the surface of lakes and reservoirs. Algal blooms have caused nuisance, aroused public indignation, and increased the cost of water treatment. It is the purpose of this paper to present a review of the current knowledge on eutrophication, its effects on water quality and an appraisal of its causes and control.
Some Effects of Pesticides on Mississippi Waters
Year: Authors: Bingham C.R.
Over the past twenty years much has been said, pro and con, about the effects of various pesticides on surface waters in Mississippi and the other Continental United States. In past years reported fish kills, where insecticides were the prime suspect, have gone invalidated as the Mississippi Game & Fish Commission had not the capability to analyze for insect.icides. In certain lakes in the Yazoo Mississippi Delta repeated attempts to restock largemouth bass (Micropterus salmoides) has met with no success. Insecticide pollution was suspected of being responsible for the failure of the bass stocks to take. In 1967 the Fisheries Division of the Mississippi Game &Fish Commission, supported by Federal D-J funds, undertook a two year insecticide surveilence of one of the aforementioned lakes (Wolf Lake). A Delta Lake, (Mossy Lake) that supports a good bass population, was selected for comparison. The present account compares the insecticide levels found in the waters, sediments, and fish flesh from the two lakes during the 1968 period. It also compares the tolerance of bluegill from Mossy Lake and Wolf Lake to endrin, toxaphene, and DDT.
The Forest’s Role in Producing Quality Water
Year: Authors: Qualls C.P.
Before discussing any subject, we need to define our terms. What is "Quality" water? "Quality" usually refers to the combined physical, chemical, and biological characteristics of water which determine the adequacy of any supply to satisfy the requirements of its’ uses. Water is never found in its pure state in nature. All natural water contains impurities derived from the natural environment or from the waste products of man’s activities. The use of the water determines the amounts of these impurities that can be tolerated. In some instances, forests may contribute to particular impurities that are critical to a particular use. Water from swamps, bogs, and marshes may contain vegetative residues which cause the water to be highly colored and exhibit a disagreeable odor and taste which render it unsuitable for certain uses. Streams fed by water percolated through the soil mantle in a forest area may contain a higher mineral content than if the water was delivered to the stream by oversurface flow.
Mississippi River Potamology Studies
Year: Authors: Elliott C.M.
Potamology is "the science of rivers." The potamology program of the-Vicksburg District of the Corps of Engineers is involved in the development of the science of the Mississippi River within the Vicksburg District. Our ultimate goal is to develop a workable knowledge of the basic principles controlling the transport of water and sediment in the Lower Mississippi River, and to apply this knowledge toward effectively and economically stabilizing the river for flood control and navigation.
The Economic Impact of Water Resource Development Projects
Year: Authors: Burrough D.L.
The purpose of this presentation is to suggest a rational and workable procedure for use in estimating the basin and national economic impact of water resource development plans. By impact I mean the economic effects - changes in economic activity in an area economy that are attributable to the construction and operation of water resource development projects.
River Flood and Stage Forecasting in Mississippi
Year: Authors: Munro D.B.
River Flood and Stage Forecasts are prepared by the Weather Bureau division of the United States Environmental Science Services Administration. The intent of this paper is to give a brief, nontechnical resume of River Forecasting in the State of Mississippi.
The Economics of Containerization
Year: Authors: Mayberry D.M.
Assuming that most everyone knows what containerization is, yet realizing that some may not, I feel that a definition of containerization is desirable. Containerization is a means of shipment whereby a large number of individual packages are consolidated in a physical envelope made of aluminum, steel, wood, plastic and/or rubber that can be lifted by mechanical means and is used for the transportation, security, protection and preservation of cargo contained therein. It is also designed for repeated use and for the through transit of cargo by different forms of transport. A container can be interchanged between truck, train, barge and ocean vessel.
Soil Evaluation and Corrosion Control Procedures for Ductile and Gray Iron Pipelines
Year: Authors: Sears E.C.
The Cast Iron Pipe Research Association has for some 40 years studied various aspects of the service performance of these pipe in the soil environment. These studies have developed a substantial amount of information for designers and users of pipe including data on the soil corrosion resistance of gray and ductile iron pipe, procedures for testing and evaluating soils for corrosiveness and means of protecting pipe in corrosive soils. This paper will review these aspects of the Association’s research work.
Consolidation of Sediments in a Small Reservoir in North Mississippi Measured In Situ with a Gamma Probe
Year: Authors: McHenry J.R., Hawks P.H., Gill A.C.
The accumulation of sediment in a reservoir is determined by a sediment survey. Depths of sediment measured at selected points within the reservoir are used to compute the volume of sediment. To calculate the total weight of the accumulated sediment, it is necessary to supply a value for the density of the sediment. In many sediment surveys, densities of sediments are estimated, not measured. The difficulty in accurately measuring the densities of sediments in place is partly responsible for the omission.
Sediment Transport Rates for Coles Creek and Buffalo River Near Natchez, Mississippi - Progress Report
Year: Authors: Willis J.C., Bowie A.J., Parsons D.A.
Reliable estimates of the sediment yield and transport rates may be crucial in insuring success of river rectification works like those proposed by the Corps of Engineers for Coles Creek and Buffalo River. Numerous transport relationships have been proposed for estimating the bed material transport rates. Each computation method has met with varying degrees of success and failure depending upon the validity of underlying assumptions for a particular application. In addition, the fine sediment load or wash load, which may account for most of the sediment load of a stream, eludes any general computation method based on streamflow variables. Thus, at least a minimum flow measurement and sampling program for each channel in question is required to verify existing procedures or to develop new, more reliable or simpler procedures for estimating the transport quantities.
A New Era in Port Development
Year: Authors: Priest M.S.
The word is "containerization." In its current usage, it might be defined as the packaging and transport of cargo in containers of such size and shape as to minimize handling and time in transit and to maximize the efficient use of available carrier space. The full ,meaning of the word lies in its application to general cargo, as distinguished from single or special cargo. The idea of shipping merchandise in some sort of box, crate or can is about as venerable as shipping itself. In a sense, truck trailers, railway freight cars and ships are all containers. However, with respect to port operations, the word container has acquired a specific connotation. The transfer of sealed containers between carriers such as the trucking lines and the railways has been going on for sometime. Most of us have seen truck trailers riding the railways in the "piggyback" operation. It is only natural that the seagoing carriers would someday join the club. The rush to participate has been of such proportions as to create alarm that it may be overdone.
The Relationship of Water Resources to the Industrial Develolpment of Jackson County, Mississippi
Year: Authors: Koonce P.A.
In a determined effort to provide the deep water harbor facilities vital to the development of the area, the Jackson County Board of Supervisors and the County Legislative Delegation succeeded in obtaining the passage of local and private legislation during the 1954 Session of the Mississippi Legislature which enabled Jackson County to appropriate and spend"funds in the amount of $2,000,000 for the development of the area known as Bayou Casotte. Pursuant to such legislation, the voters of Jackson County, Mississippi approved the $2,000,000 bond issue by a 13 to 1 margin. Such action marked the end of the "Shallow Draft Era" of the Port of Pascagoula and the beginning of a dramatic Industrial Development Program, which is the subject of this paper.
River Basin Planning Concepts and Their Use in Resource Development
Year: Authors: Wells R.H.
River basins are usually the most appropriate geographical units for planning the use and development of water and related land resources in a way that will realize fully the advantages of multiple use, reconcile competitive uses through choice of the best combination of uses, coordinate mutual responsibilities of different agencies in levels of government and other interests concerned with resource use.
Hydrologic and Hydraulic Design of Small Dams
Year: Authors: Harper, Jr. R.T., Dove M.L.
The purpose of this paper is to present some of the more important criteria, methods, and techniques that were employed by the above authors in the hydrologic and hydraulic design of a system of small dams for flood control purposes. An attempt will be made to analyze the major design considerations for a system of small dams in the Bayou Bartholomew Basin, located in Arkansas and Louisiana. The paper will consider a specific design for a given basin, rather than the general design applicable to any system of small dams. It should be made clear at the outset that the resulting design to be presented could very easily be one of several, depending upon the criteria by which the engineer is governed and his own ingenuity. The ideas presented in this paper are considered appropriate and adequate for the Bayou Bartholomew study. The current study on Bayou Bartholomew is of a preliminary nature, and, therefore, no detailed studies or estimates, required of a final design, have been made.
A National Forest Water Quality Program
Year: Authors: Hofeldt V.H.
The Federal Water Quality Act of 1965 brought into focus a growing awareness of the vital importance of protecting and improving the quality of one of the Nation’s most essential resources. We too in the Forest Service are taking a second critical look at our responsibilities and opportunities in regard to water quality. Suddenly we are aware that "good", compared to other water may not be good enough.
Depth of Area Rainfall From Point Rainfall
Year: Authors: Brooks, Jr. B.P., McWhorter J.C.
The purpose of this paper is to present a method of determining depth of area rainfall when point rainfall is known. Determination of area rainfall is important in watershed runoff studies, flood control planning, and similar problems, and the current methods of determining area rainfall are not satisfactory for all applications.
The Law Little Used and Sometimes Abused - in Flood Damage Abatement
Year: Authors: Walker W.R.
Floods are a natural phenomena and are said to occur when water, flowing in a well-defined channel, exceeds its banks, or when a body of water, such as an ocean or bay, experiences high tides as a result of severe storms or hurricanes. Overbank flows are not abnormal. The flood plain acts as a natural reservoir and temporary channel for the excess water. In the economy of nature, the channel efficiently conveys the dayto- day flow and calls upon its flood plain only when needed. Typically, a river uses some portion of its flood plain about once in two to three years. At average intervals of, say 25, 50, 100 years, the river may inundate its entire flood plain to a considerable depth. Although records of floods permit estimation of frequency of flooding, it is not possible to forecast the year a flood will occur on any given watercourse. Floods become a problem to man only when he competes with rivers for the use of flood plains. This competition between man and the rivers has been long and costly. Use of flood plains involving periodic damage from floods is not in itself, a sign of unwarranted or inefficient development. It may well be that the advantages of flood plain location outweigh the intermittent cost of damage from floods. Further, there are some kinds of activity which can only be conducted near a watercourse.
The Relation of Water Resources to the Recreational Potential of the Mississippi Gulf Coast
Year: Authors: Armenakis A.A.
My purpose this morning is to present to you one section of a study entitled: THE RELATION OF WATER RESOURCES TO THE INDUSTRIAL AND RECREATIONAL POTENTIAL OF THE MISSISSIPPI GULF COAST. I am prepared to report in brief form my findings concerned with the relation of water resources to the recreational potential of the M.s sis sippi Gulf Coast. My presentation is divided into five parts. First, is the National Demand for Recreation in which I will discuss national trends. Second, is the "Assets" of the Mississippi Coast, i. e., what I consider to be the main assets. Third, I will present the plans I have discovered that exist for the islands and the present status of these plans. Fourth, I shall relate to you other plans that exist for the tri-county study area. And last, I will discuss my own personal evaluation of the coast.
Water Resource Management as Related to Water Pollution Control
Year: Authors: Beck A.N.
The subject of this paper, "Water Resources Management as Related to Water Pollution Control" represents a rather wide field. There are many ramifications involved in Water Resource Management and Water Pollution Control which make it difficult to confine a discussion to any single aspect. Because man-made impoundments, especially those built primarily for developing peaking electric power, are of great concern to those of us in Alabama responsible for water quality control, this paper will be devoted to this topic.
The Tennessee Valley Authority’s Small Watershed Research
Year: Authors: Eklund C.D.
The purpose of this paper is to describe briefly some of TVA’s small watershed research projects--their objectives and the principal results where these are available. The projects discussed herein follow generally in order of their establishment, or as the findings on early projects or the new requirements of TVA’s development programs led to the need for special watershed research. Figure 1 shows the location of selected watershed projects within the Tennessee Valley.
Deer Island - Sandbar or Goldmine?
Year: Authors: Hunter, Jr. D.A.
The Gulf Coast, originally French, was lost to the British in 1763 and they in turn lost it to the Spanish in 1780. In the meantime, the French continued to hold New Orleans. In 1810 the Gulf Coast area revolted against the Spanish rule and formed the Republic of West Florida. The United States recognized the revolt and took possession of the territory. In 181 I, the area was annexed to the Mississippi Territory, which became the twentieth state in the Union. In the early years of development, the state economy thrived on large cotton plantations, and the Mississippi River as an avenue of trade. No seaports were developed along the Gulf Coast, and by 1830 New Orleans had grown into an influential marketing and financial center. Large fortunes were made, and it was only natural that residents who were financially able sought relief from the heat and humidity of New Orleans by buiIding along the Gulf Coast. This was the beginning of the establishment of the Gulf Coast as a summer playground. Since then the area has grown steadiIy as a tourist mecca.
Time-of-Travel of Solutes in Mississippi Streams
Year: Authors: Thomson F.H.
Within Mississippi, the primary role of the Water Resources Division of the U.S. Geological Survey is to collect water facts. In 1963, the USGS turned part of its attention to the collection of data concerning the time-of-travel of solutes in Mississippi streams. The need for such data is emphasized by the growing problems associated with the use of natural water bodies to dilute and carry away wastes. Time-of-travel information is needed to fully appraise the problems of pollution and to arrive at reasonable solutions to these problems.
Perspective on Water Management in Mississippi Based on Comparisons with Other States and a Survey of In-State Water Managers
Year: Authors: Mitchell G.F., Krane D.A.
Water rich states, who in the past have depended on abundant water resources, particularly groundwater, for attraction and support of industry and agriculture, now realize that proper management of these resources will be required if supplies are to be available in the future. To illustrate, in the State of Mississippi approximately 90% of all drinking water. Over 50% of all industrial process water and over 80% of irrigation and rice farming water come from the ground. Hence, a comprehensive integrated groundwater-surface water resource management plan is needed for Mississippi, if the state is to be in a position of not allowing water resources to inhibit full economic growth and development. In order to develop guidelines for an effective water management plan for Mississippi, other states’ water management plans were assessed, and a survey of Mississippi’s water managers was conduct. ed. The results of these studies are discussed in the next sections.
The Role of Forestry in Hydrology
Year: Authors: Thompson G.A.
Whether we mechanically control water or work with it through the natural processes, we must know something of the science of three geophysical groups. The first treats of the origin and distribution of water on the earth’s surface and is known under the general term of hydrology. The second, climatology, is known and is measurable. The third is the science of the development and properties of the soil. This paper deals with the latter.
Applications of the Equations of Unsteady Flow in Water Resources
Year: Authors: Amein M.
The equations of unsteady flow play a very important role in the study of numerous problems involving the movement of water, such as overland flow, flow in rivers and channels, the motion of tides and long waves in oceans, surges in canals and harbors, etc. They consist of the equations for the conservation of mass and of momentum. Although they have been known for a long time, yet mathematical difficulties have prevented the application of the complete equations to the solution of many problems, and approximate methods have been used instead. In recent years, many of these difficulties have been resolved, and the equations have received considerable attention aimed at their application to water resources.
The National Forests in Mississippi and their Water Resources
Year: Authors: Moore, Jr. R.M.
When you look at water in this manner it is easy to see that it is the most valuable resource of the National Forests. Our efforts to date to manage the water resource have been generally limited to rehabilitation of damaged watersheds. In the course of the Nation’s growth a great deal of damage was done to the forest and range lands. The causes and consequences are now well known to all and it is improbable that we would permit the’ wide-spread denudation and depletion of the past to be repeated. However, in acquiring lands for National Forest purposes we purchased many thousands of acres of land which are now sources of accelerated flood runoff and damaging sediment. Such areas need rehabilitation to restore their productivity.
Reforestation and Water Resources of the Yazoo-Little Tallahatchie Watershed
Year: Authors: Ursic S.J.
The watersheds of the Little Tallahatchie and Yazoo Rivers of north Mississippi have the dubious distinction of being among the most severely eroded in the Eastern United States. My subject today is the role of reforestation in improving the hydrologic condition of this area.
Sociology of Watershed Development
Year: Authors: Dasgupta S.
The major focus of this study Is on the effects of attitudes of local residents and their participation on success of watershed development prograrns. 2 This has been done by comparing two communities. referred to hereinafter as Community A and Community B, which were at different levels both in favorable predisposition of Its residents toward watershed development and its relative success as a program.
Valley Sedimentation in North Central Mississippi
Year: Authors: Happ S.C.
The hilly part of the Yazoo drainage basin in north central Mississippi (fig. 1) is one of several sections of the United States where notable valley sedimentation is associated with culturallyaccelerated soil erosion. It is an area of severe erosion of silty upland soils of loessial origin, and gullying of underlying Coastal Plain sedimentary formations which are mostly sandy.
The Role of the Mississippi Geological Survey in Ground-Water Development and Investigation in Mississippi
Year: Authors: Shows T.N.
There is a need for information on ground water in Mississippi. Today, we see the economy of the State changing fran basically agricultural to an agricultural and industrial type eooncmy. Increased agricultural i=igation and the tremendous industrial growth in recent years has focused attention on water supplies and management.
The Corps of Engineers and Water Quality Control
Year: Authors: Ruland W.E.
The Corps of Engineers, through the development of water resource programs throughout the Nation, has provided water quality control for a number of years. This has taken the form of low flow augmentation and stream flow regulation. In order to prevent the degradation of a stream to a point where it no longer is of value for any purpose for other use downstream, careful consideration must be given to its flow characteristics and its ability to recover through natural processes. Numerous factors enter into this recovery capability, but one of the prime factors is considered to be the quantity of flow available at all times. If Mother Nature were cooperative enough to provide even distribution of stream flows throughout each year there is little doubt that adequate waste disposal systems, of economic feasibility, could be provided to provide high-quality, valuable waters to users downstream of the effluent discharges. Unfortunately, this is not the case. An increase in minimum flows, that is to say, Low Flow Augmentation, becomes an extremely important and valuable factor in the control of water quality.
Use of Hydraulic Models for Water Quality Investigations
Year: Authors: Simmons H.B.
In our modern and complex civilization, the term ’’water quality" has different meaning to those having different primary interests. For example, those concerned with providing adequate supplies of water for potable, industrial, and irrigation uses are often concerned about possible contamination of freshwater sources by sea water. On the other hand, the marine biologist who is concerned with establishing and maintaining the optimum brackish water environment to serve as breeding and nursery areas for fin and shell fishes may be equally concerned about possible contamination of such areas by fresh water. Thus, good quality water to one interest or group of interests may be poor quality water to other interests, and vice versa. Hydraulic models have been used for many years for a wide variety of purposes, and use of models for estuary studies dates back to 1887 when Professor Osborne Reynolds constructed and operated a small-scale model of the Mersey Estuary in England as an aid in designing a comprehensive plan of training works to maintain depths adequate for navigation at the entrance to this estuary. Navigation and channel maintenance problems are among the more important ones studied in modern estuary models, although model techniques and procedures have now been refined to such extent that such models can also be used to investigate saltwater intrusion, the diffusion, dispersion, and flushing of contaminants, hurricane surge phenomena, and many other problems.
Flood Losses and Flood Plain Planning
Year: Authors: Arnold J.D.
Nationwide, we are continuing to make improper uses of lands subject to flooding. Consequently, we are suffering increased flood losses; now averaging about one billion dollars annually. We should no longer overlook the risks involved in developing uses of flood plain areas. The Federal Government has recently expanded a program for furnishing technical information and advice on flood hazard situations. The service is provided, upon request, to Federal agencies, state and local governments, and to other interested groups. The purpose is to contribute information for planning reasonable uses of flood plain areas and to advise on lneasures to reduce further losses to existing investments. It is not the purpose of the program to abrogate the programs for the construction of flood control works. Neither is it the purpose of this program to halt any community’s economic growth. The Corps of Engineers and the Tennessee Valley Authority, in its area, conduct the program. This paper is a synopsis of the background and intent of this expanded program as assigned to the Corps of Engineers and as it pertains to inland areas. Coastal areas present somewhat different problems.
Current Studies Relative to Reservoir Operation in the Interest of Water Quality
Year: Authors: Grace, Jr. J.L.
Although water quality is not definitive since each user has his own standards and anyone user may have an entirely different attitude toward the quality of water which he receives for use and that which he wastes, the public has become increasingly aware of the term water quality as it applies to personal consumption and recreational use. Public Law 660 as amended by the Federal Water Pollution Control Act Amendments of 1961 (PL 87-88), the Water Quality Act of 1965 - (PL 89-234), and the Clean Water Restoration Act of 1966 were significant steps toward an accelerated national attack on pollution and enhancement of the quality and value of our water resources. In a broad sense, reservoir operation in the interest of water quality has been common practice throughout history; although, operation in the past has been governed primarily by other single or multiple purposes for which the projects were constructed. The need for increased efforts to obtain optimum use of our water resources becomes more evident with the growth of population and industry and the increased demands on our water resources.
A Preliminary Study of the Effect of Urbanization of Floods in Jackson, Mississippi
Year: Authors: Wilson K.V.
A cooperative program of the U. S. Geological Survey and the City of Jackson has provided for the collection of flood records from Jackson streams since 1953. This report consists of a preliminary analysis of the flood data collected under this program. The analysis is limited to a study of the peak discharges. The report "Floods in Mississippi, Magnitude and Frequency" was published by the Mississippi State Highway Department in 1961. It presented curves from which the magnitude and frequency of floods from most rural drainage areas can be estimated by using independent variables of size, shape, and location of basin. The urgent need for flood-frequency data on small urbanized areas necessitated this report on Jackson’s streams. The streams analyzed are Eubanks, Town, Lynch, and Three-Mile Creeks. Their drainage basins above the gaged points are outlined on figure 1, a topographic map of Jackson.
Behavioral Aspects of Water Resources Development
Year: Authors: Wilkinson K.P.
There is a need to develop an effective conversation between sociologists and those concerned in a practical way with the systematic management of water. Evidence from other areas of research on natural resources problems, such as agricultural development l and forest fire prevention,2 suggests that substantial benefits of both a practical and a theoretical nature can be gained through carefully designed and focused cooperative programs. Relatively littie social science research to date has dealt with water resources, and that has been primarily in economics and recently, political science. 3 Sociologists have barely entered the field, owing partly to their tendency to underestimate the significance of such an area for the development of social theory and partly to the fact that only recently have they been invited. If insights are to be effectively shared between sociologists and those in the field of water management, problems of language, perspective and role definition, which arise in any conversation, must be resolved. A strategy is described in this paper by which the resources of sociology may be applied to problems of social behavior in water management. The aim of this strategy is to develop a cooperative relationship which can contribute to the solution of practical problems and to the articulation of meaningful generalization, about man’s fundamental relationships with his natural environment. 4 effectively shared between sociologists and those in the field of water management, problems of language, perspective and role definition, which arise in any conversation, must be resolved. A strategy is described in this paper by which the resources of sociology may be applied to problems of social behavior in water management. The aim of this strategy is to develop a cooperative relationship which can contribute to the solution of practical problems and to the articulation of meaningful generalization .4
Sediment Production From a Lafayette County Mississippi Gully
Year: Authors: McDowell L.L., Bolton G.C., Ryan M.E.
Gullies are a significant source of sediment in the Tallahatchie River watershed. In many areas the erosional processes have cut through the loessial mantle into the underlying Coastal Plains sands. This has resulted in the destruction of productive upland agricultural areas and downstream damages through channel aggradation, floodplain deposition, and reservoir sedimentation. A detailed study by Woodburn (4) 1/ revealed that one-third of the 294,OOO-acre Little Tallahatchie River watershed has been severely damaged by gullying.
Probabilities of Sequences of Wet and Dry Days at State College, Mississippi
Year: Authors: McWhorter J.C., Brooks, Jr. B.P.
Precipitation events are of particular interest to us in the planning and decision-making relative to our day to day operations. We are interested in whether a day will be dry or wet and we rely on the short range forecast to provide this information for operations that will be performed tomorrow or the next day. There are situations when we must make a choice relative to the timing of an event well in advance of its occurrence. In order to bring our best knowledge to bear on this problem we apply a statistical treatment to the long-term records of daily events to determine the probability of occurrence of various rainfall amounts. It is also possible to determine the probability of sequences of wet and dry days. (1) This type of information gives us a better understanding of our environment and enables us to plan future operations in order to minimize the adverse effects of precipitation and to take full advantage of the favorable aspects of precipitation.
Yazoo River Navigation Project
Year: Authors: Ahlrich V.C.
In 1962 the District Engineer held a public hearing in Greenwood, Miss., to ascertain the views and desires of local interests regarding improving the Yazoo River for navigation. During the hearing, local interests expressed their desire for a year-round 9-foot navigation channel from Vicksburg to Greenwood. They pointed out that even under unfavorable conditions, traffic had increased during recent years. They stated that greater use would have been made of the waterway had a dependable 9-foot navigation channel been available. The primary objective of any navigation plan considered for the Yazoo River was to develop the most feasible plan, both from an engineering and economic standpoint, that would provide a suitable waterway from which a rnaxirmun amount of transportation savings would accrue. However, in arriving at any plan, consideration was given to other factors; i.e., flood control, water supply, pollution control, power, recreation, fish and wildlife, so that any plan would fit well into the total long run development of the water resources of the basin.
Comprehensive River Basin Planning in the Pascagoula
Year: Authors: Wells R.H.
The development or improvement of our Nation’s water resources to satisfy existing and future needs antedates our present Federal Government. In 1784, the Commonwealth of Virginia and the State of Maryland appointed commissioners to develop a plan for opening and improving navigation of the Potomac River and opening a proper road between the waters of the Potomac and the most convenient western waters in the Ohio Basin. This bi-state commission was chaired by George Washington and a report submitted on January 22, 1785. On February 6, 1965, President Johnson directed the Secretary of Interior to prepare a program on the Potomac River Basin to serve as a model of conservation. A Federal Interdepartmental Task Force was created to develop approaches to accomplish the President’s objectives. Comprehensive River Basin Surveys are now underway in every one of the 48 states and cover about 75 percent of the land area. Forty-three separate surveys are in progress.
Preliminary Investigation of the Ground-Water Resources of Copiah County
Year: Authors: Bicker, Jr. A.R.
The absence of contemporary published information on the groundwater resources prompted the inclusion of a comprehensive study of the water resources as an integral part of the investigation of the Geology and Mineral Resources of Copiah County. The purpose of this investigation is to collect and interpret information on the availability of ground-water. The increasing demand for more water for domestic, industrial and municipal use has emphasized the need for water facts to keep abreast of the demand. This preliminary report nor the final report will answer all of the water problems of the County, but will provide data which can serve as a guide for future planning and development. Information being collected on water wells and test holes throughout the County consists of both geologic and hydrologic data where available. Field analyses of iron content, pH values and total hardness are being conducted on selected wells. Complete chemical analyses have been made on a number of wells by the Sanitary Engineering Department of the Mississippi State Board of Health. Figure 1 shows the location of water wells inventoried to date.
The Asiatic Clam in Mississippi
Year: Authors: Grantham B.J.
The Asiatic clam was first collected in the United States in 1938 (Gregg, 1947), and since that time the spread has been nothing short of phenomenal. This small bivalve molluscan (Mollusca Pelecypoda, Heterodonta, Corbiculidae) is a member of the genus Corbicula and some dispute exists as to the exact species in Mississippi at the present time. Its life history differs from the common fresh water mussels in the family Unionidae in that the larval stages are not parasitic. The larval stage of Corbicula becomes planktonic, settles to the bottom and acquires its shell. Corbicula is probably often confused with small unionids or possibly with the so-called fingernail clams of the family Sphaeriidae. Although this confusion exists, they are quite distinct from any other in that the shells are much heavier and thicker than either form mentioned and they possess heavy ridges on each valve.
Sewage Stabilization Activities of Sewage Thermophiles
Year: Authors: Ladner C.M., Brown L.R., Tischer R.G.
For the last several years, investigations have been conducted in our laboratory into the possibilities of developing a high temperature sewage stabilization process. Tischer, Cook, and Brown (1962) reported that a high temperature stabilization process might be of value in treating normal domestic sewage. Attributes of such a system include the destruction of pathogenic bacteria during processing and the ability to control the microbial population, since there are fewer organisms capable of growing at temperatures of 550 C and higher. Brown, Cook, Mickelson, and Tischer (1966) demonstrated that the enteric pathogens in the genera Salmonella and Shigella were destroyed within minutes at the treatment temperatures employed and, that the Biochemical Oxygen Demand and Chemical Oxygen Demand reductions were comparable to those obtained with a mesophilic treatment process. These studies also indicated that during the aeration of normal domestic sewage at elevated temperatures, populations in the neighborhood of 107 to 108 thermophiles per ml rapidly developed. This paper will report on the isolation of organisms responsible for the stabilization process and report on some of their characteristics.
Recreation in Water Resources Projects
Year: Authors: Harris C.H.
An upsurge of interest in the outdoors has taken place in recent years and though it has important roots in the past, it can be viewed primarily as a product of the growing affluence of today’s society. Traditionally, Americans have looked to the hinterlands for raw materials and supporting resources. Today they are looking for something more. Urban dwellers want to emerge from the high-rise apartments, get off the paved streets, and find green fields, wooded hillsides, and clear, clean water in which to play. Although wholesome outdoor environments may be available in remote parts of the country, this does not satisfy their need. They want and need these resources within reach for a weekend outing, if not an afternoon picnic. As urbanization progresses and as both the city and farm populations enjoy greater opportunity to participate in recreation activities, the enhancement of recreational opportunities, preservation of natural beauty and aesthetic values, and conservation of fish and wildlife assume increasing prominence in development of the nation’s resources. Today, full consideration must be given to the entire natural and social environment in planning and developing water resources.
Effects of Pollution on Water Resource Development in the Pascagoula Basin
Year: Authors: Stone G.E., Wakefield J.W.
The Southeastern Comprehensive Water Pollution Control Project has been making a careful, deliberate study of the Pascagoula River Basin since 1964. The study and its resultant plan for controlling water pollution is only one of eighteen such studies of southeastern river basins in various stages of completion; and the Southeastern Project is only one of twenty similar projects which the Federal Water Pollution Control Administration has or soon will have underway, covering all major river basins of the country. The projects are created under the Federal Water Pollution Control Act "....in cooperation with other Federal agencies, with State water pollution control agencies and interstate agencies and with the municipalities and industries involved .... " to develop comprehensive programs to control water pollution. The initial charge is directed at pollution of inters tate waters and their tributaries, but the phrase "and improving the sanitary condition of surface and underground waters" extends the cooperative effort to any waters subject to sanitary degradation. The Pascagoula River Basin study is being made in cooperation with the Mobile, Alabama office of the U. S. Army Corps of Engineers and numerous other Federal and State agencies under the further authority of a 1961 resolution by the United States Senate Committee on Public Works. This latter authority is for a comprehensive basin study (Type II) of water resource and related land resource needs and development. The Southeastern Project’s contribution to this coordinated effort in the Pascagoula Basin is virtually complete, and this paper is based on the findings.
Purpose and Utilization of Economic Base of Water Resource Projects
Year: Authors: Bayley, III F.
What will be the population in Jackson, Mississippi in the year 2020? Will the per capita income of those residing here be in the $1,000, $2,000, or perhaps $5,000 range? How many workers do you think will be employed by plants producing paper and allied products, chemicals, or petroleum products? To become still more refined, what percent of those people living here will be more than 12 years old and what will be their median level of education? By now you may be wondering just what these Characteristics of economics and demography have to do with water resource development. The answer is - plenty - if you are attempting to plan projects that will adequately meet the needs in this area for the next 50 years. $1,000, $2,000, or perhaps $5,000 range? How many workers do you think will be employed by plants producing paper and allied products, chemicals, or petroleum products? To become still more refined, what percent of those people living here will be more than 12 years old and what will be their median level of education? By now you may be wondering just what these Characteristics of economics and demography have to do with water resource development. The answer is - plenty - if you are attempting to plan projects that will adequately meet the needs in this area for the next 50 years. This is the type of information that is usually developed in an economic base study. This stUdy identifies and measures, insofar as practicable, the social, physical, economic, and technological factors that affect economic development and growth. First a thorough analysis is made of existing economic conditions including a compilation of available historic data on such measures as population, personal income, and employment. Past and present trends are compared with national and regional growth. If they differ, an attempt is made to identify the factors that produce this variation. Next, the available raw material, people, geographic location, climate, and other resources of the study area are inventoried to evaluate the potential development of the area. Finally, the trend and magnitude of future activity is expressed in terms of population, personal income, employment, households, land use, agricultural and industri.al production, and other indicators of economic actiVity usually for the next 50 years. These projections. either singularly or in combination, have a relationship to one or more purposes of water resource development. thus, they may be translated into water needs.
The Water Laws of Mississippi
Year: Authors: Pepper J.W.
Prior to the passage of the water rights act in 1956, the people of Mississippi were more concerned with legal means to dispose of excess water than they were about rights to use water. To our knowledge, there have been no court decisions in this State dealing with the right to use water. Laws for the use of water were based on the Riparian Doctrine of the old common law, handed down from the earliest history of this country. When the first settlers came to Mississippi, the streams were important as a means of transportation, a source of power for small mills, water supply for domestic uses, and as habitat for fish life. When you carry water in buckets, you use a rather limited amount -- the other uses required the water to remain in the stream. Under some definitions of Riparian Doctrine, a person whose property abuts on the bank of a stream is entitled to have the stream flow past his property--undiminished in quantity, and unimpa:!lred. in quality. This could mean that no dams could be constructed to store excess waters~ and no water withdrawn from the streams for municipal~ industrial or agricultural uses. To further complicate matters~ it is difficult to define riparian land. Many streams have highways or roads running along their banks. These roads are owned by the State or County~ and could cause the land away from the stream to be classified as non-riparian~ since there is a break in the ownership. In some states~ the courts have followed a "reasonable us&’ concept that will allow restricted uses of water from the streams. A riparian owner can use a reasonable amount of the water from the stream flowing past his property. It is necessary for the courts to determine the extent of this "reasonable us&’ ~ and if conditions change because of competition from additional water users~ these amounts have to be adjusted. It is no wonder that very few people in Mississippi really understood just what water rights they possessed.
Test-Well Exploration for Fresh Aquifers on the Mississippi Gulf Coast
Year: Authors: Newcome, Jr. R.
Deep test drilling and well development in the past 2 years have revealed tremendous quantities of fresh ground water on the Mississippi gulf coast. Far below the previously known extent of fresh-water occurrence lie thick sand aqUifers capable of yielding millions of gallons of water per day to properly constructed well fields. Water supplies have already been developed in deep aquifers at the National Aeronautics and Space Administration’s (NASA) test facility in Hancock County. Here, wells as deep as 1,875 feet produce more than 3,000 gpm (gallons per minute) each for cooling the flame deflectors in the Saturn rocket test stands. The NASA wells are the largest in Mississippi-- one of them produced 3,500 gpm by natural flow. Artesian pressure in the deep aquifers is sufficient to force water about 100 feet above the land surface in the coastal region. Water temperatures are about 100 degrees Fnhrenheit. The attainment of these reliable supplies of water is a direct result of exploratory test drilling directed by knowledgeable use of what to the casual observer would appear to be unrelated bits of information derived from several different sources.
Ground Water in the Tatum Dome Area, Lamar County, Mississippi
Year: Authors: Taylor R.E.
In January 1961 the U.S. Atomic Energy Commission began supervision of Project Dribble activities at the Tatum salt dome in connection with the Advanced Research Project Agency’s Vela Uniform program of detection of seismic signals from underground atomic tests. Exploratory activities were initiated to establish dome definition and characteristics and to define the geology and hydrology of the area. This report will consider the ground-water conditions that exist in the Tatum dome area as determined from the investigations by the U.S. Geological Survey. The area under consideration is approximately 4 square miles and includes the dome and a mile-wide border. The Tatum dome is located in the southwest quarter of Lamar County about 18 miles southwest of Hattiesburg, Miss., and about 16 miles southeast of Columbia, Miss. (fig. 1). Previous dome investigations were begun in 1941 by various companies undertaking oil, gas, and sulfur explorations. Since 1961 the U.S. Government’s activities have expanded the available data through the drilling of 34 test holes.
Forest Hydrology Research in Mississippi
Year: Authors: Ursic S.J.
The title of this paper is Forest Hydrology Research in Mississippi.
The Effects of Flood Prevention Measures Installed in Bluff Tributaries on Reduction of Sediment and Flood Damages in the Yazoo River Delta
Year: Authors: Watts W.L.
The part of Mississippi known locally as the Bluff Hills area is a belt varying in vidth from 3 to 30 miles along the eastern side of the Yazoo-Mississippi Delta extending from the Tennessee line to Vicksburg and south through Natchez to the Louisiana line. This paper pertains to conservation work on that part of the Bluff Hills from Yazoo City to the Tennessee line, a portion of the Yazoo River Basin. Topography, geology, misuse of the land during the last 150 years, and other factors have caused this to be one of the more severely eroded areas in the United States. Sediment from the hill streams fills channels in the Delta portion of the Yazoo River and its tributaries-causing breaks in levees and general flooding of surrounding areas, inflicting severe damage on farmland, farm buildings, roads and bridges, urban areas, and public utilities. Maintenance costs on ditches, levees and farm drainage systems amount to millions of dollars annually on approximately 425,000 acres as a direct result of sediment and floodwater from the eroded Bluff Hills.
Offshore Boundaries
Year: Authors: Williams P.H.
The research under Project No.6 has pursued a comprehensive examination of the water resource in Mississippi, beginning with the most important single water resource, the Mississippi Sound. The Sound is generally described as: The water area lying between the Mississippi mainland and the chain of islands including Petit Bois, Horn, Ship and Cat Islands, bounded on the East by the Mississippi-Alabama boundary, and on the West by the Mississippi-Louisiana boundary. The Sound i5 of great importance for a number of obvious reasons: The tremendous wealth that it harbors - wealth in the form of fish, shellfish, minerals and other resources; the location on its shores of numerous heavy industries that are dependent upon its waters as avenues for world commerce; and the recreational opportunities afforded by its sands and waters. But for the purposes of the research contemplated under Project No.6, the Sound assumes primary i~portance because of three principal problem areas which i~ presents: (1) the conflicting claims by three states to control and govern its appropriation and exploitation; (2) the conflicting claims by municipalities, Port Authorit~s, counties, and industries to withdraw its waters for drinking, manufacturing, and channel stabilization; and (3) the rapidly growing usage of its waters for pollution carriage - a usage that poses a threat to all other uses. A logical first step in the proposed research was the resolution of the first proble~ area - the conflicting claim to control and govern the Sound. This necessitates a clarification and delineation of the boundaries of the State of Mississippi within the Sound, thus marking the geographical area within which the second and third problems will assume relevance.
Iron and Manganese in Mississippi Water Supplies
Year: Authors: Robinson, Jr. L.R.
Water is one of the most important of all natural resources and is, indeed, absolutely essential for the existence of life. It has been estimated that by 1980 the total water requirements in the United States will be twice those of 1954 and by 2000 the requirements will be triple the requirements of 1954 (1). It is anticipated that by 2000,888.4 billion gallons of water per day will be withdrawn from all sources for all purposes and of this almost 160 billion gallons per day will be consumed. One of the reasons for this rapidly increasing demand on the nation’s water resources is the increased per capita consumption for domestic use. Increased living standards create increased demands and governmental assistance programs are making potable running water available to more and more families. In the mid 1930’s the Water Facilities Act was passed which provided for development and irrigation of agricultural land mainly in the West and Mid-West. In 1954 the Act was broadened and extended to the eastern and southern parts of the country. This "Soil and Water Loan Program" act was amended in 1961 by the Farmers Home Administration Consolidation Act. This made it possible for rural communities to obtain loans under very liberal conditions for the purpose of constructing public water supplies for domestic use and livestock watering (2). On November 7, 1962, the Farmers Home Administration approved a loan of $50,000 for the construction of a rural water system by the Abbeville Water Association, Inc., in Lafayette County. This was the first system built in the State of Mississippi under the program. Since that time more than 334 associations have been formed and applications made for these systems in the State. Of these about 150 projects have either been completed or are making certain progress toward that end. This number of systems is especially noteworthy when compared to the total number of about 250 water systems in incorporated communities in the State which have been financed by other means.
Design of Major Drainage in the Mississippi Delta
Year: Authors: Bayley, Jr. F.
The design of major drainage improvements involves a study to resolve three principal factors. First, the design flows, or the amount of water which will be carried within channels without overflow; second, the design flowline or the elevation at which the design flows will be carried and third, the type and amount of work required to provide channels adequate to carry the design flows without overflow. Most of this discussion will be devoted to design flows since this is the most controversial factor and the one which most influences the frequency and duration of overflow, the benefits to be derived, and the economic Justification of the work.
Aerobic Sewage Stabilization at Elevated Temperatures
Year: Authors: Brown L.R., Cook D.W., Mickelson J.C., Tischer R.G.
Previous studies conducted in this laboratory have shown that the thermophilic bacterium Bacillus circulans could effect a reasonable reduction in the Chemical Oxygen Demand (COD) of normal domestic sewage. The results of these studies were sufficiently encouraging to warrant investigating the possibility of designing an aerobic sewage disposal system operated at thermophilic temperatures. In this connection, it is of importance to know not only the performance of this system in terms of removing the Biochemical Oxygen Demand (BOD) and suspended solids of the influent but also to evaluate the system in terms of its ability to destroy pathogenic microorganisms in the sewage. This paper will describe some of the attributes of an aerobic thermophilic sewage treatment process and the affect of this process on microorganisms contained in normal domestic sewage.
Runoff and Soil Loss From Pastured Loess Soils in North Mississippi
Year: Authors: Carter C.E., Denby F.E., Doty C.W.
Runoff and erosion studies were initiated in 1957 on pastured areas at the North Mississippi Branch Experiment Station, Holly Springs, Mississippi. These studies were part of an extensive field research program to establish the erosion potential of various soil-cover complexes in the loessial soils of the southeastern United States. After approximately 6~ years of continuous operation these investigations were discontinued at the end of the 1963 calendar year. This paper gives a summary of the data and a discussion of the influence of several management features and topographical characteristics on runoff and erosion.
Decontamination of Radioactively Contaminated Water by Slurringly with Yazoo and Zilpha Clays
Year: Authors: Goldsmith W.A., Middlebrooks E.J.
The level of radioactivity of most radionuclides discharged into watercourses must be reduced before the water can be consumed. Various attempts have been made to determine the most economical method for this activity reduction. These attempts have included slurrying with powdered metal and clays, chemical coagulation, and ion exchange on synthetic resins. One of the most practical methods of activity reduction is that of slurrying with clay. Good results have been obtained by this method and by the addition of clay in conventional water treatment processes such as chemical coagulation and lime-soda ash softening. A majority of the clays under investigation or in use today require pretreatment before they are suitable for use. The clays chosen for this experiment were Yazoo and Zilpha clays. These clays are abundant throughout most of the state of Mississippi and may be easily mined near the surface. If these untreated clays have decontamination properties comparable with those of other treated clays, the cost per gallon of removing radioactive materials could be materially reduced.
The Value and Use of Macro-Invertebrates in Evaluating Stream Pollution Conditions
Year: Authors: Grantham B.J.
Most Mississippians are aware that one function of the Mississippi Game and Fish Commission is that of a pollution regulatory agency. The Commission’s legal authority in this field is in the realm of industrial pollutants. However, any type of waste discharge into a stream, be it municipal or industrial, is of vital concern. Historically, the Commission acted merely as a regulatory agency, but in 1959, the fact was recognized that additional background data on the actual condition of streams were badly needed. As a result of this, a cooperative project known as the Pollution Studies Program was initiated between the Mississippi Game and Fish Commission and the U. S. Fish and Wildlife Service. This program is primarily to determine the effects of pollutants on Mississippi streams. The three objectives are: (1) to determine the effects of pollutants on water quality, (2) fish populations; (3) and aquatic invertebrates (Macro-invertebrates). Three studies have been completed and a fourth is currently underway.
Sedimentation Survey of Lake Guayabal, Puerto Rico
Year: Authors: McHenry J.R., Hawks P.H.
The Puerto Rico Water Resources Authority, on recommendation of the U. S. Bureau of Reclamation (1, 2),2/ authorized a resurvey of the sediment conditions in Guayabal Reservoir, P. R. As a part of this program, the use of a gamma probe (radioisotope sediment probe) was sought to measure the in situ density of the sediments. As the Bureau of Reclamation’s sediment probe was not available the services of the Agricultural Research Service were solicited. An agreement was reached whereby the USDA Sedimentation Laboratory (Mr. Donald A. Parsons, Director), Soil and Water Conservation Research Division J made equipment and personnel available to the Puerto Rico Water Resources Authority for the sediment survey of Guayabal Reservoir. This report gives the results of the sediment survey conducted by personnel of the USDA Sedimentation Laboratory working at Lake Guayabal J P. R. J in September-October 1964, in cooperation with personnel of the Puerto Rico Water Resources Authority. The equipment used and the techniques employed are described and the experimental data are discussed.
Some Aspects of Water Balance in the Gulf Coastal Flatwoods
Year: Authors: Miller W.F.
In 1860, Hilgard (4) described the area we now know as the Pamlico Terrace of the Coastal Flatwoods as, " ... a level meadowland, in which there is scarcely any distinction into upland and lowland. Almost the only living being, ... which inhabits this region at present, is the prairie-lark; settlements are few and far between, and no attempt is made to cultivate the soil, the raising of stock being the only occupation of the inhabitants." Further, "The timber is formed altogether by diminutive Long Leaf Pines (sic), averaging about 25 feet in height by 2 1/2 to 4 inches in thickness, which stand at considerable distances (40 or 50 feet) apart,..." The passage of 106 years has altered this picture considerably - we see the Coast as a highly urbanized, industralized area. The ecological community has also been altered, particularly the species forming the overs tory of the area. Where Hi1gard found only "diminutive" longleaf pine (Pinus palustris), the species now found is slash pine (Pinus elliottii). Hilgard was, however, a most astute observer and a fair prognosticator - he was correct in his assumption that agronomic crops would never be important in the area, but incorrect when he stated that the pine meadows would produce only timber "fit for little else than (charcoal) burning... ." In 1965, the three coastal counties of Mississippi produced 25,304,000 board feet of sawlogs, poles, piling and crossties, and 100,232 cords of pulpwood (8): approximately 25% of the area of these counties could be classified as IIpine meadows". Although the area is unique among ecological communities, the same condition is also found along the Atlantic Coastal Plain; its uniqueness is derived from an abundance of rainfall combined with a particular physical soil condition and topographic situation. This paper presents some preliminary results of an investigation concerned with the water balance relationships of the extensive, poorly drained areas of the Coastal Flatwoods. The study is sponsored by the Mississippi Water Resources Research Institute and supported by funds provided by the United States Department of Interior as authorized under the Water Resources Research Act of 1964, Public Law 88-379.
The National Forests in Mississippi and Their Water Resources
Year: Authors: Moore, Jr. R.M.
The National Forests in Mississippi are directly made up of 1.1 million acres of land. The products from these lands are timber, wildlife, forage, recreation, minerals and water. Each of these has a definite value. Timber produces 150 million feet per year for a value of 2 million 700 thousand dollars; minerals, through oil production, returns 1 million 800 thousand dollars. All this we take for granted. When you say "National Forests" everyone thinks about trees and, to most, this is the most important product. But, what about water? The streams from National Forests in Mississippi produce 718 billion gallons of water a year. If we placed a value of 10 cents per thousand gallons, this would represent about 72 million dollars per year. This is more than 14 times the combined values of all other resources. When you look at water in this manner it is easy to see that it is the most valuable resource of the National Forests. Our efforts to date to manage the water resource have been generally limited to rehabilitation of damaged watersheds. In the course of the Nation’s growth a great deal of damage was done to the forest and range lands. The causes and consequences are now well known to all and it is improbable that we would permit the’ wide-spread denudation and depletion of the past to be repeated. However, in acquiring lands for National Forest purposes we purchased many thousands of acres of land which are now sources of accelerated flood runoff and damaging sediment. Such areas need rehabilitation to restore their productivity.
Forest Service Management Requires Consideration of Known Watershed Properties to Enhance Water Quality and Resource Values
Year: Authors: Williams J.A.
The intent of this paper is primarily to demonstrate that activities of man on the forested watersheds of the Nation have an appreciable effect on the available water resource. It will be brought out that these activities are subject to gUidance in accord with a reasonable plan or design. Additional information concerning the water supply in Mississippi, Forest Service organization and objectives and other related items will also be discussed. From this development, it will become apparent that the net size of the water resource about which the Water Resources Research Institute is doing research is primarily determined by forested watersheds.