Microplastics in the Mississippi River and Mississippi Sound

Year: 2015 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).

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).

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.

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).

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)

Effects of cover crops on edge-of-field water runoff in the mid-south

Year: 2015 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.

Rice yield and groundwater level as affected by irrigation management in Mississippi Delta

Year: 2015 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.

Row Spacing of Alfalfa Interseeded into Native Grass Pasture Influences Soil-Plant-Water Relations

Year: 2015 Authors: Dhakal M., West C.P., Deb S.K., Villalobos C., Kharel G.

Interseeding alfalfa (Medicago sativa 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_stem and Ψ_leaf were measured weekly in 2017 and 2018 growing seasons. Soil VWC was not affected by alfalfa cultivars (P > 0.05), whereas alfalfa row spacings differed (P < 0.05). Narrow spacing caused lower (P < 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 (P > 0.05). Soil water depletion increased with alfalfa crown density (r = 0.60, P < 0.05) in association with enhanced evapotranspiration and denser root mass below 30-cm soil depth. Grass and alfalfa Ψ_stem and Ψ_leaf 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.

Characterization of Runoff Water Quality from Established BMP Soybean Production Systems

Year: 2015 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.

Management Practice Impacts on Runoff and Sediment Loads in the Upper Sunflower River Watershed

Year: 2015 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.

Freshwater Delivery to the Gulf of Mexico: an analysis of streamflow trends in the Southeast US from 1950 - 2015

Year: 2015 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.

Case Studies of Rapid Dam Breach Modeling during Flood Events

Year: 2015 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.

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.

Climate Extremes and Cover Crop Influence Yields and Water Use of a Maize-Soybean Cropping System

Year: 2015 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.

Effects of Varying Suites of Agriculture Conservation Practices on Water Quality in the Mississippi Delta

Year: 2015 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^-1 for total suspended solids (TSS), 0.38 mg L^-1 for total phosphorus (TP), 0.09 mg L^-1 for nitrate-nitrite (NO3^--NO2^-), and 0.81 mg L^-1 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^-1 for TSS, 1.21 mg L¹ for TP, 0.32 mg L^-1 for NO3^--NO2^-, and 1.04 mg L^-1 for NH₄⁺. 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.

Field Measurements of Irrigation Reservoir Levee Erosion

Year: 2015 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: 2015 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.

Can Diatom Assemblages Identify Important Stressor-Response Relationships Necessary to Establish Nutrient Management Goals for Mississippi Alluvial Pl

Year: 2015 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.

Despite their differences, managed and non-managed wetlands in the Mississippi Delta achieve similar functional outcomes

Year: 2015 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.

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.

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.

Monitoring and Characterization of Water Resources in Priority Areas throughout Mississippi

Year: 2015 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.

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Office of Land and Water Resources: Overview of Mississippi's Participation in the National Ground-Water Monitoring Network

Year: 2015 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.

Oyster Restoration and Management

Year: 2015 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.

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Water consumption and yield variability of nonirrigated and irrigated soybeans in Mississippi dominant soils across years

Year: 2015 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.

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.

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.

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^-1 grain, in contrast, irrigated soybean consumed 440, 526, and 478 mm water and yielded 6264, 3109, and 3031 kg ha^-1 grain.

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.

APEX simulated grain yield of rainfed soybean ranged broadly from 2.24 to 6.14 Mg ha^-1 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^-1, respectively. Simulated yield potential without water stress due to irrigation varied from 4.47 to 6.51 Mg ha^-1. Compared with rainfed soybean, the average increase in yield by irrigation ranged from 0.34 to 1.60 Mg ha^-1 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^-1. 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.

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Rice irrigation strategies: Alternate wetting and drying and methane reductions

Year: 2015 Authors: Runkle R.K., Suvocarev K., Reba M.

Approximately 11% of the global 308 Tg CH₄ anthropogenic emissions are currently attributed to rice cultivation. In this study, the impact of water conservation practices on rice field CH₄ 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 CH₄ 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 CH₄ emission significantly less for the AWD treatment. The substantial decrease in CH₄ emissions by AWD supports previous chamber-based research and offers strong evidence for the efficacy of AWD in reducing CH₄ 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 CH₄ 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: 2015 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.

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.

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Grazing Cattle Preference for Automated Water Troughs and Shade Trees versus Pond Use for Drinking and Heat Stress Mitigation

Year: 2015 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.

Simulating cotton water use and yield under rainfed and full irrigation conditions using RZWQM2 model in the Lower Mississippi Delta Region

Year: 2015 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^-1, and the highest irrigated yield were more than 3600 kgha^-1.

Interplay of water quality and vegetation in restored wetland plant assemblages from an agricultural landscape

Year: 2015 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.

Nutrient and phytoplankton changes in Roundaway Lake after a managed hydrologic drawdown

Year: 2015 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.

Application of AnnAGNPS for Evaluating the Nutrient Loading Control of an On-Farm Water Storage (OFWS) system in East Mississippi

Year: 2015 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: 2015 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.

Collection and analysis of water quality and benthic macroinvertebrate and algal community data to support nutrient criteria development in northweste

Year: 2015 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.

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Water Quality in Bangs Lake: effects of recurrent phosphate spills to a coastal estuary: Year 2

Year: 2015 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.

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Effects of land use on wetland plant diversity in Mississippi

Year: 2015 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.

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Current Surface Water and Groundwater Studies in the Central Mississippi Region

Year: 2015 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.

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Regional Overview of Work by the Water Resources Division in Northeast Mississippi

Year: 2015 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.

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Assessment of tailwater recovery system and on-farm storage reservoir water and nutrient harvesting

Year: 2015 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.

Natchez Trace Ecological Forecasting and Water Resources: Utilizing NASA Earth Observations to Assess Current and Historic Wetland Extent along the Na

Year: 2015 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: 2015 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.

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Real Time Groundwater Monitoring: Mississippi River Valley Alluvial Aquifer and the underlying Tertiary aquifers of the Mississippi Delta

Year: 2015 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.

Variable pathways and geochemical history of seepage under the Mississippi River levee: Observations from the 2011, 2015, and 2016 floods

Year: 2015 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.

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Prediction of Future Agricultural Water Needs in Mississippi Delta and Blackland Prairie under Surface Water Supply and Groundwater Pumping Scenarios

Year: 2015 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.

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Ecological Significance of Phyllosphere Leaf Traits on Throughfall Hydrology, Biogeochemistry and Leaf Litter among Quercus Species in the Southeaster

Year: 2015 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).

Multidisciplinary Remediation: An Analysis of Chlorinated Metabolites in Groundwater Contaminated by Pentachlorophenol Following 15 Years of Air/Biosp

Year: 2015 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.

Crop water requirement, rainfall deficit and irrigation demand of major row crops in Mississippi Delta

Year: 2015 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.

Characterization of Surface Water Quality in Sunflower River Watershed, Mississippi

Year: 2015 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_3-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_3-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).

The Effect of Government Structure and Size on the Performance of Mississippi Community Water Systems

Year: 2015 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.
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Comparison among three methods for suspended-sediment sampling of the Mississippi River at Vicksburg, Mississippi

Year: 2015 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.
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Use of Small Unmanned Aerial Vehicle in Agricultural Research

Year: 2015 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.
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Use of Small Unmanned Aerial Vehicle in Agricultural Research

Year: 2015 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: 2015 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: 2015 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 (NH₃ 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: 2015 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: 2015 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: 2015 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.
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Bottomland hardwood restoration and implications for water quality

Year: 2015 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.
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Improving Water Quality through Watershed Planning, Design and Innovative Outreach Activities

Year: 2015 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.
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The Catalpa Creek Watershed Project and Watershed Demonstration, Research, Education, Application and Management (D.R.E.A.M.) Center

Year: 2015 Authors: Ingram R.

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.

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".

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.

Automated identification of sediment sources and sinks: Tool development to support water quality planning

Year: 2015 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: 2015 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: 2015 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: 2015 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.
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Climate Change and Coastal Eutrophication

Year: 2015 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: 2015 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 Oregon II 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 http://www.ncddc.noaa.gov/hypoxia/.
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New Approaches and Analytical Tools for Studying Mercury in the Gulf of Mexico: Sources and Transformations

Year: 2015 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.^1,2 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.
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Monitoring Network Design to Assess Potential Water-Quality Improvements Associated with the Mississippi Coastal Improvement Program in the Mississippi

Year: 2015 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.
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Using low-grade weirs as a best management practice for phosphorus and sediment mitigation

Year: 2015 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: 2015 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 in-situ 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.
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Contribution of total dissolved phosphorus in irrigation runoff from the Mississippi River Valley alluvial aquifer to phosphorus concentrations in a D

Year: 2015 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: 2015 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.
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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: 2015 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: 2015 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 Palaemonetes pugio, 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. pugio 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: 2015 Authors: Macy A., Cebrian J., Cherry J.

With milder winter temperatures, the black mangrove Avicennia germinans has been expanding its range poleward into temperate salt marshes, forming an ecotone of mixed vegetation between two ecosystem-defining vegetations (Mangrove forest and Spartina salt marsh). In stable conditions, Avicennia outcompetes Spartina alterniflora, while occasional disturbances favor Spartina. 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 (Avicennia) 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.e. Spartina alterniflora). Spartina has been suggested as a wave buffer f Avicennia, aiding in the succession to an Avicennia-dominated system, so treatments will also include areas where Spartina has been clipped. Finally, fertilizer will be applied to half the plots to stimulate a decrease in the root: shoot ratio, possibly making Avicennia 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: 2015 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.

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: 2015 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: 2015 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.
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Utilizing NASA Earth Observations to Assist the Audubon Mississippi Coastal Bird Stewardship Program with Habitat Monitoring and Restoration Planning Activities

Year: 2015 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: 2015 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.
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Crop Water Use in the Mississippi Delta

Year: 2015 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.
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Evaluation of Management Strategies to Promote Water Resource Conservation in Louisiana

Year: 2015 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: 2015 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: 2015 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: 2015 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: 2015 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: 2015 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^-1, 0.05 to 17.0 mg L^-1, and 0.0 to 17.0 mg L^-1. 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: 2015 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.
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The Benefits and Potential for Well Fields in the Mississippi Delta

Year: 2015 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.
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Pecan Bayou: A Pilot-Scale Comprehensive Conservation Watershed Proposal

Year: 2015 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.
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Pathogen Indicator Monitoring in the Ross Barnett Reservoir

Year: 2015 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: 2015 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: 2015 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: 2015 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.
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Assessment of On-Farm Water Storage System (OFWS) for design and nutrient variability in the Mississippi Delta and East Mississippi

Year: 2015 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.
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Water Resource Planning and Solution Implementation in the Mississippi Delta: YMD Joint Water Management District

Year: 2015 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: 2015 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: 2015 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.
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Evaluation of Input Variables for Neural Network Models used in Groundwater Level Forecasting for Sunflower County, Mississippi

Year: 2015 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: 2015 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-H₂CO₄ waters, SO₄-Cl-HCO₃ waters and HCO₃-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 SO₄). The second PC is characterized by (eH, P and H₂CO₃) 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: 2015 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: 2015 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: 2015 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: 2015 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: 2015 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.
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Soil Water Monitoring Using Wireless Sensor Network

Year: 2015 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.
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Tillage and Cover Crop Effects on Runoff Water and Soil Quality

Year: 2015 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 (Gossypium hirsutum L.) production are reviewed here. In Study 1, no-tillage (NT) or minimum tillage (MT) with or without cover crop (rye [Secale cereale], balansa clover [Trifolium michelianum ssp. Balansae], 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: 2015 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: 2015 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: 2015 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 periodR²= 0.53 to 0.68 and NSE = 0.49 to 0.66) and validation perio(R²= 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 (R² = 0.58 and NSE = 0.56) and at the validation sub-basin (R² = 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: 2015 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.
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Heterogeneous Vertical Flow through Oxbow-Wetlands: Soil Chemistry, Wetland Tree Growth, and Groundwater Recharge

Year: 2015 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: 2015 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 (Brunnichia ovata) and trumpet creeper (Campsis radicans) frequently were recorded at 50% or more of our sample points per wetland, while knotweed (Polygonum spp.) was common throughout. Additionally, woody species, such as buttonbush (Cephalanthus occidentalis), swamp chestnut oak (Quercus michauxii), slippery elm (Ulmus rubra) 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: 2015 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 priori 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.
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Groundwater and Surface-Water Interactions of a Stream Reach and Proposed Reservoir within the Pascagoula River Basin: George County, Mississippi

Year: 2015 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: 2015 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: 2015 Authors: Barlow J.R., Connor J.H.

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.

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.

Water quality in Bangs Lake: Effects of recurrent phosphate spills to a coastal estuary

Year: 2015 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.

Downstream Water Quality and Quantity Impacts Of Water Storage Systems in a Mississippi Delta Watershed

Year: 2015 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 km² 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.
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