SOIL EROSION, SEDIMENT YIELD, CONSERVATION STRUCTURES, AND DSS FOR SUSTAINABLE LAND MANAGEMENT ON SEMIARID RANGELAND WATERSHED
Location: Southwest Watershed Research
Title: A rangeland hydrology and erosion model
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2011
Publication Date: June 30, 2011
Citation: Nearing, M.A., Wei, H., Stone, J.J., Pierson, Jr. F.B., Spaeth, K., Weltz, M.A., Flanagan, D.C., Hernandez, M. 2011. A rangeland hydrology and erosion model. Transactions of the ASABE. 54(3):1-8.
Interpretive Summary: Runoff and erosion rates predicted from models for rangelands are important quantitative indicators for rangeland health and for assessing the effectiveness of conservation practices. Government agencies, rangeland managers, conservationists and rangeland scientists are in need of a technology that will allow them to estimate these values. In this study we developed a new technology for predicting infiltration, runoff, and soil erosion specifically for rangelands of the western United States. The new model is scientifically rigorous, in that it is based on state-of-the-art understanding of infiltration, runoff, and soil erosion processes on rangelands. It is based on an extensive set of measured data that has been collected over the past 20 years. Also, it accessible to the average user via the internet, and requires only information that is commonly collected by or available to rangeland scientists and managers. This new technology will enable improved estimation of hydrology and erosion by water on rangelands across the western United States, which will lead to an improved ability to manage this extensive and sometimes fragile natural resource.
Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing rangeland health and conservation practice effectiveness. An erosion model to predict soil loss specific for rangeland applications is needed because existing erosion models were developed from croplands where the hydrologic and erosion processes are different from that found on rangelands. The Rangeland Hydrology and Erosion Model (RHEM) was designed to fill that need. RHEM represents erosion processes under disturbed and undisturbed rangeland conditions, it adopts a new splash erosion and and thin sheet-flow transport equation developed from rangeland data, and it links the model hydrologic and erosion parameters with rangeland plant communities by providing a new system of parameter estimation equations based on 204 plots in 49 rangeland sites distributed across 16 western U.S. states. RHEM estimates runoff, erosion, and sediment delivery rates and volumes at the spatial scale of the hillslope and the temporal scale of a single rainfall event. Experiments were conducted to generate independent data for model evalidation, and the r2 of runoff and erosion predictions were 0.87 and 0.50 respectively, which indicated the ability of RHEM to provide reasonable runoff and soil loss prediction capabilities for rangeland management and research needs.