SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Modeling and prioritizing interventions using pollution hotspots for reducing nutrients, atrazine and e. coli concentrations in a watershed 
Authors:Abimbola, O., A. Mittelstet, T. Messer, E. Berry and A. van Griensven 
Volume (Issue):13(1) 
Article ID:103 
URL (non-DOI journals): 
Broad Application Category:hydrologic and pollutant 
Primary Application Category:BMP and/or cropping system assessment 
Secondary Application Category:pollutant cycling/loss and transport 
Watershed Description:1,610 km^2 Big Sandy Creek, a tributary of the Little Blue River located in southeast Nebraska, U.S. 
Calibration Summary: 
Validation Summary: 
General Comments: 
Abstract:Excess nutrients and herbicides remain two major causes of waterbody impairment globally. In an attempt to better understand pollutant sources in the Big Sandy Creek Watershed (BSCW) and the prospects for successful remediation, a program was initiated to assist agricultural producers with the implementation of best management practices (BMPs). The objectives were to (1) simulate BMPs within hotspots to determine reductions in pollutant loads and (2) to determine if water-quality standards are met at the watershed outlet. Regression-based load estimator (LOADEST) was used for determining sediment, nutrient and atrazine loads, while artificial neural networks (ANN) were used for determining E. coli concentrations. With respect to reducing sediment, total nitrogen and total phosphorus loads at hotspots with individual BMPs, implementing grassed waterways resulted in average reductions of 97%, 53% and 65% respectively if implemented all over the hotspots. Although reducing atrazine application rate by 50% in all hotspots was the most effective BMP for reducing atrazine concentrations (21%) at the gauging station 06883940, this reduction was still six times higher than the target concentration. Similarly, with grassed waterways established in all hotspots, the 64% reduction in E. coli concentration was not enough to meet the target at the gauging station. With scaled-down acreage based on the proposed implementation plan, filter strip led to more pollutant reductions at the targeted hotspots. Overall, a combination of filter strip, grassed waterway and atrazine rate reduction will most likely yield measureable improvement both in the hotspots (>20% reduction in sediment, total nitrogen and total phosphorus pollution) and at the gauging station. Despite the model’s uncertainties, the results showed a possibility of using Soil and Water Assessment Tool (SWAT) to assess the effectiveness of various BMPs in agricultural watersheds. 
Keywords:best management practices; Soil and Water Assessment Tool (SWAT); nutrients; E. coli; atrazine; Big Sandy Creek Watershed (BSCW)