SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Impact of spatial discretization of hydrologic models on spatial distribution of nonpoint source pollution hotspots 
Authors:Wang, Y., H.J. Montas, K.L. Brubaker, P.T. Leisnham, A. Shirmohammadi, V. Chanse and A.K. Rockler 
Journal:Journal of Hydrologic Engineering 
Volume (Issue):21(12) 
Article ID:04016047 
URL (non-DOI journals): 
Broad Application Category:hydrologic and pollutant 
Primary Application Category:HRU, subbasin, grid and/or landscape unit delineation effects 
Secondary Application Category:critical source area assessment 
Watershed Description:9.14 km^2 Watts Branch, a tributary of the Anacostia River, which drains portions of Prince George County, Maryland, and Washington DC, U.S. 
Calibration Summary: 
Validation Summary: 
General Comments: 
Abstract:The soil and water assessment tool (SWAT) was used to investigate the effects of hydrologic response unit (HRU) thresholds (0–20%) on predictions of multiple variables by calibrated and uncalibrated models in a 10.4-km2 urban watershed in the U.S. Mid-Atlantic region. Surface runoff, discharge, sediment yield, and nutrient yield were simulated in stream and on land, and used to spatially identify hotspots for each constituent. SWAT2012 was able to produce accurate discharge and nitrogen estimates that were not sensitive to HRU thresholds. HRU thresholds significantly affected sediment and phosphorus predictions in calibrated and uncalibrated models. Constituent hotspots identified by an uncalibrated model with a 0% HRU threshold were found to be acceptable for the urban watershed under study, except for sediment. Hotspots identified with calibrated models, with HRU thresholds of 5% or less, fit with the identification of on-land sediment and nutrient hotspots. These findings suggest that researchers should carefully consider HRU thresholds when predicting on-land variables of small urban watersheds similar to the watershed in this study when using SWAT 
Keywords:Spatial distribution; Nonpoint pollution; Stormwater management; Hydrologic models; Geographic information systems.