A Comparison of a SWAT Model for the Cannonsville Watershed with and without Variable Source Area Hydrology

Abstract

In this study, two different versions of the Soil and Water Assessment Tool (SWAT) are used to simulate the Cannonsville Watershed. These versions are referred to as SWAT_TS and SWAT_VSA. The SWAT-VSA model distributes overland flow in ways that are consistent with variable source area hydrology, while the SWAT_TS model does not. Since many water quality models, such as SWAT, use some form of the curve number equation to predict storm runoff, these models may fail to accurately describe the effects of variable source areas (VSAs), which are mostly important in rural, humid areas, such as upstate New York. These two models are compared by calibrating each for flow, phosphorous and sediment against measured data.