Proceedings of the 2022 Mississippi Water Resources Conference

Year: 2022 Authors: Venishetty V., Parajuli P.B.

Deterioration of water quality due to non-point source (NPS) pollution is prominent across the world. Agriculture is the major source of NPS pollutants that is mainly induced by runoff. Yazoo River Basin (YRB) is the largest watershed in the state of Mississippi, of which about 47% of land use is large scale agriculture and the remainder is Forest (50%), wetlands, water and urban (3%). Major Crop in the region are Corn, Soybean and Cotton. Continuous and Crop rotation practices are applied in the region. To minimize and mitigate pollution from agricultural lands, numerous Best Management Practices (BMP) were being implemented in the state and country. By using Soil and Water Assessment Tool (SWAT), impact associated due to BMP implementation is quantified. SWAT model efficiency has been tested using Nash-Sutcliffe Efficiency index (NSE) and Coefficient of Determination (R²). Calibration and validation of various Hydrologic (Streamflow) and water quality parameters (Total Suspended Sediment (TSS), Total Nitrogen (TN), and Total Phosphorus (TP)) is done for various USGS gage stations spread across the watershed. Model performance is Good for streamflow, Satisfactory for TSS, TN and TP. Management practices such as Vegetative Filter Strips (VFS), Tail Water recovery Ponds (TWP), and Cover Crops were preferred for analysis in this study. Simulations from VFS implementation show significant reductions in sediment, and nutrient concentrations in water, and similar results are expected to be found from TWP and Cover crop practices as well. Hence it is essential to understand and quantify the impact of BMP on water quality.