Validation of the Unit Stream Power Erosion and Deposition (USPED) Model at Yakima Training Center, Washington

During the last seventy years, numerous models have been developed to predict soil erosion; some models also predict concomitant sediment deposition. All have been proven inadequate and/or inaccurate in one respect or another. This paper discusses the application of the new-generation Unit Stream Power Erosion and Deposition (USPED) model at the US Army's Yakima Training Center (YTC), Washington. We incorporated a novel approach that compares model results with observed soil erosion and sediment deposition across the landscape in a spatially distributed fashion. The model results matched visually estimated values 90% of the time, providing an encouraging validation of the model. Historically, erosion models have been compared with sediment outflow from watersheds, providing no information regarding sources and sinks of erosion and deposition within watersheds. The USPED model is relatively simple to apply and the validation approach provides information in terms of the intensity and spatial distribution of soil erosion and sediment deposition that can be used to optimize the placement and size of soil erosion and sediment control efforts.