ARS | Publication request: SWAT Revisions for Simulating Landscape Components and Buffer systems

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: May 9, 2007
Publication Date: June 25, 2007
Citation: Bosch, D.D., Arnold, J.G., Volk, M. 2007. Swat revisions for simulating landscape components and buffer systems. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE), June 17-20, 2007, Minneapolis, Minnesota.

Interpretive Summary: Conservation practice programs supported by the Government have played a large role in maintaining environmental health throughout rural regions in the U.S. Watershed scale natural resource models are being used to quantitatively evaluate the benefits of these programs. However, one shortcoming of these models is their inability to accurately represent water flow and transport from higher positions in the landscape to lower positions. The Soil Water Assessment Tool, SWAT, has been revised to properly describe this transport process. The revised watershed model was tested for a hillslope in a small Georgia watershed. The model simulates important changes in the hydrologic water balance as the water moves from the field area at the top of the hillslope, through grass and wooded buffers, and eventually into the stream. While additional testing is necessary, the revised model holds considerable promise as a tool for watershed management

Technical Abstract: Methods for simulating different landscape positions within the SWAT model are being examined. A three component system, consisting of the watershed divide, the hillslope, and the floodplain landscape positions, has been developed to address flow and transport across hydrologic response units prior to concentration in streams. The modified SWAT model is capable of simulating flow and transport from higher landscape positions to lower positions within a single river basin. The revision was developed to address variable source areas within watersheds and stream-side buffer systems which exist alongside many streams. The enhanced model will allow for more accurate simulation of natural transport processes within a hillslope. The revision was tested using data collected from a low-gradient watershed near Tifton, Georgia, USA which contains heavily vegetated riparian buffers. The modified model provided reasonable simulations of surface and subsurface flow across the landscape positions without calibration. The application demonstrates the applicability of the model to simulate filtering of surface runoff, enhanced infiltration, and water quality buffering typically associated with riparian buffer systems.