THE USDA WATER EROSION PREDICTION PROJECT (WEPP)

The Water Erosion Prediction Project (WEPP) models are intended to rep lace the Universal Soil Loss Equation for predicting soil erosion in t he United States. The WEPP programs are process-based models that oper ate on a daily time step to estimate soil, vegetation, and surface res idue conditions when a rainfall event occurs. This information is then used to predict the infiltration, runoff, erosion, and sediment loss for each individual event, and then long-term estimates are made using summations of the single event predictions. This paper describes the history of the model development and the major components of the WEPP models and provides brief examples of how they may be applied by actio n agencies.