SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Spatially distributed assessment of short- and long-term impacts of mutiple best management practices in agricultural watersheds 
Authors:Renschler, C.S. and T. Lee 
Journal:Journal of Soil and Water Conservation 
Volume (Issue):60(6) 
Article ID: 
URL (non-DOI journals):http://www.jswconline.org/content/60/6/446.short 
Broad Application Category:hydrologic & pollutant 
Primary Application Category:model and/or data interface 
Secondary Application Category:pollutant cycling/loss and transport 
Watershed Description:.66 ha Cos 130, .65 ha HSp 3 and 5.11 ha ChiC-5, located respectively in: Coshocton, west central Ohio; Holly Spring, northern Mississippi; Chickasha, western Oklahoma; all in the U.S. 
Calibration Summary: 
Validation Summary:WEPP validated for annual runoff & sediment for four small watersheds; linked model than verfified vs. WEPP for 3 watersheds (most r2 values > .99) 
General Comments:Three models were combined (WEPP, GeoWEPP, & SWAT), that are designed to operate at different spatial scales, into a simple assessment tool that supports more spatially explicit BMP analyses (short- and long-term). A linked GeoWEPP-SWAT model facilitated injection of WEPP output as point sources into SWAT: the linked model allows porting of WEPP functionality to larger watersheds. Short- and long-term assessments of pre- & post-BMP implementation evaluation for 3 watersheds; grassed waterways & field borders were the BMPs evaluated at each site. Long-term assessments were found to be more consistent thatn short-term; long-term results were similar to WEPP-only but the short-term results were not. Limitations were found with SWAT's ability to characterize grassed waterways. 
Abstract:Best management practices (BMPs) are a critical tool for preventing or mitigating the degradation of water quality caused by soil erosion. However, currently available assessment models are primarily designed for use over and, therefore, are only valid over these particular spatial and temporal scales. This study investigates the feasibility of combining three models that were designed for use at different spatial scale into a single assessment tool that allows for more detailed, spatially-explicit assessment of BMPs over both short (four to eight years) and longer (100 year) time scale. The three models evaluated were: 1) the Water Erosion Prediction Project (WEPP) model for hillslope and small watershed up to 260 ha (642 ac); 2) the Geospatial interface for WEPP (GeoWEPP), which utilizes geographic information system (GIS) or precision farming datasets of topography, soils, and landuse to automatically derive WEPP model input; and 3) a linked GeoWEPP-SWAT model, which injected WEPP model output as point sources into the Soil and Water Assessment Tool (SWAT). The linked GeoWEPP-SWAT model provides a mechanism for applying the WEPP model to larger watershed scales beyond the validity of its channel routing algorithms. This paper summarizes the challenges, validity, and opportunities of this modeling approach for BMP assessment in large watersheds. 
Keywords:BMP, GeoWEPP, scale, SWAT, WEPP