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United States Department of Agriculture

Agricultural Research Service

Research Project: Assessment, Conservation and Management of Rangelands in Transition

Location: Northwest Watershed Management Research

Title: Evaluating the capability of the enhanced Rangeland Hydrology and Erosion Model (RHEM) for modeling the soil erosion impact of disturbance on rangelands

Authors
item Al-Hamdan, Osama -
item Hernandez, Mariano -
item Pierson, Frederick
item Nearing, Mark
item Williams, Christopher
item Stone, Jeffry
item Boll, Jan -
item Weltz, Mark

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2013
Publication Date: N/A

Technical Abstract: In this study, enhancement of the application of RHEM has been made using a new approach for predicting concentrated flow erosion in order to expand its applicability to disturbed rangelands. The enhanced model was conceptualized based on observations and results of experimental studies on rangelands disturbed by fire and/or tree encroachment. The enhanced version of the model incorporates: a new stream power- based sediment detachment rate equation that applies a dynamic erodibility concept, a new concentrated flow width equation, and new empirical parameterization equations for estimating hydraulic friction and erodibility as a function of readily available vegetation cover and surface soil texture data. The enhanced version of the model was evaluated against rainfall simulation data for three different sites that exhibit some degree of disturbance by fire and/or tree encroachment. Evaluation results indicated the ability of the model to predict erosion at the plot scale with a satisfactory range of error. The new version of the model was able to match the predicated effect of disturbances across a wide range of ecological sites with diverse vegetation and ground cover conditions. The good performance of the enhanced model nominates it to be a practical management tool for quantifying erosion and assessing erosion risk following rangelands disturbance (e.g. wild fire, prescribed fire, and/or tree encroachment).

Last Modified: 10/20/2014
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