Estimating water erosion and sediment yield with GIS, RUSLE, and SEDD

A comprehensive methodology that integrates erosion models, Geographic Information System (GIS) techniques, and a sediment delivery concept for estimating water erosion and sediment delivery at the watershed scale was presented. The method was applied to a typical agricultural watershed in the state of Idaho, which is subject to increasing soil erosion and flooding problems. The Revised Universal Soil Loss Equation (RUSLE) was used to assess mean annual water erosion. The Sediment Delivery Distributed (SEDD) model was adapted to determine sediment transport to perennial streams. The spatial pattern of annual soil erosion and sediment yield was obtained by integrating RUSLE, SEDD, and a raster GIS (ArcView). Required GIS data layers included precipitation, soil characteristics, elevation, and land use. Current cropping and management practices and selected, feasible, future management practices were evaluated to determine their effects on average annual soil loss. Substantial reduction in water erosion can be achieved when future conservation support practices are applied. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion and sediment delivery. It thus provides a useful and efficient tool for predicting long-term water erosion potential and assessing erosion impacts of various cropping systems and conservation support practices.