Predicting Sediment and Nutrient Loads for Selected Agricultural Watersheds in the Midwestern United States

Changing agricultural land use and land management practices are regarded as one of the main factors driving water quality degradation. Landscapes of the Midwestern United States have experienced significant changes in expansion of corn production in response to the growing demand for corn-based ethanol. This study integrated remote sensing-derived products and the Soil and Water Assessment Tool (SWAT) within a geographic information system (GIS) modeling environment to estimate sediment and nutrient loads associated with land use change and land management practices within three selected watersheds in the Midwestern United States. The SWAT models were calibrated during a 6-year period (2000-2005) to forecast, and then validate, estimated stream flows. Then, our SWAT models were applied to estimate sediment and nutrient loadings for several future agricultural and climate scenarios.