ABSTRACT

WEPP is a new generation of erosion prediction technology designed to replace the USLE. WEPP is a daily simulation computer model for predicting soil erosion and sediment delivery from cropland, forestland, rangeland, construction sites, and urban areas. Soil erosion is modeled as a rill-interrill process that includes detachment by raindrops and flowing water and transport and deposition by flowing water. Sediment delivery is modeled in WEPP with channels and impoundments on and leading from hillslope areas. Every day the status of the soil and biomass (live and dead) is computed, including soil moisture content, evaporation, transpiration, surface roughness, residue decomposition, surface cover, and live biomass. If rain, snowmelt, or irrigation occurs, infiltration and runoff are computed. If runoff is predicted, then detachment, transport and deposition of soil by rain, irrigation and runoff in rills is computed. WEPP has been well tested for applications on cropland, rangeland, and forestland.