Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2007
Publication Date: 10/1/2007
Citation: Flanagan, D.C., Gilley, J.E., Franti, T.G. 2007. Water Erosion Prediction Project (WEPP)–Development History, Model Capabilities and Future Enhancements. Transactions of the American Society of Agricultural and Biological Engineers. 50(5):1603-1612. Interpretive Summary: Soil erosion by water continues to threaten the productivity of soils here in the United States and throughout the world. It is not practical or possible to monitor or measure the amount of soil loss everywhere in the field, so computer simulation prediction models have been developed to estimate how much erosion occurs at a certain location due to the climate, soils, slope and cropping/management of the land. Models are also used to determine the effects of applying different land management on a farmer’s field. This paper provides information on the history, management, development and current status of the Water Erosion Prediction Project (WEPP) model. WEPP is a modern erosion prediction system that allows for very easy and rapid estimation of soil erosion by water. This model greatly impacts conservation agency personnel, foresters, farmers, landowners, extension agents, and others involved in soil conservation planning and environmental assessment. Use of the WEPP model to plan appropriate conservation practices can help to greatly reduce the amounts of soil loss, maintain the agricultural production base, and minimize off-site impacts of sediment losses.
Technical Abstract: The Water Erosion Prediction Project (WEPP) was initiated in August 1985 to develop new generation water erosion prediction technology for use by federal agencies involved in soil and water conservation and environmental planning and assessment. Developed by USDA-ARS as a replacement for empirically based erosion prediction technologies, the WEPP model simulates many of the physical processes important in soil erosion, including infiltration, runoff, raindrop detachment, flow detachment, sediment transport, deposition, plant growth and residue decomposition. The WEPP project included an extensive field experimental program conducted on cropland, rangeland, and disturbed forest sites to obtain data required to parameterize and test the model. A large team effort at numerous research locations, ARS laboratories, and cooperating land-grant universities was needed to develop this state-of-the-art simulation model. WEPP project participants met frequently to coordinate their efforts. The WEPP model can be used for common hillslope applications or on small watersheds. Because it is physically based, the model has been successfully used in the evaluation of important natural resources issues throughout the United States and in several other countries. Upgrades to the model since the 1995 DOS-based release include Microsoft Windows operating system, graphical Windows-based interfaces, and integration with Geographic Information Systems. Improvements have been made to the watershed channel and impoundment components, the CLIGEN weather generator, the daily water balance and evapotranspiration routines, and the prediction of subsurface lateral flow along low-permeability layers. A combined wind and water erosion prediction system with easily accessible databases and a common interface is planned for the future.