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ARS Home » Pacific West Area » Boise, Idaho » Northwest Watershed Research Center » Research » Publications at this Location » Publication #322587

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

Location: Northwest Watershed Research Center

Title: Developing a parameterization approach of soil erodibility for the Rangeland Hydrology and Erosion Model (RHEM)

Author
item AL-HAMDAN, OSAMA - Texas A&M University
item Pierson, Fred
item Nearing, Mark
item Williams, Christopher - Jason
item HERNJANDEZ, MARIANO - US Department Of Agriculture (USDA)
item BOLL, JAN - Washington State University
item NOUWAKPO, SAYJRO - University Of Nevada
item Weltz, Mark
item SPAETH, KENNETH - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2016
Publication Date: 1/1/2017
Citation: Al-Hamdan, O.Z., Pierson, F.B., Nearing, M.A., Williams, C.J., Hernandez, M., Boll, J., Nouwakpo, S.K., Weltz, M.A., Spaeth, K.E. 2017. Developing a parameterization approach of soil erodibility for the Rangeland Hydrology and Erosion Model (RHEM). Transactions of the ASABE. 60(1):85-94.

Interpretive Summary: In this study we enhanced the applications of the RHEM model by incorporating a new soil erodibility estimation approach. The enhancements expand the model applicability as a practical land management tool for conservation planning and quantifying environemtnal benefits of alternative conservation practices. The new approach for estimating erodibility for RHEM has several advantages. First, the results of this study indicate that in general the model will be dependent on only one erodibility factor. Second, the approach addresses the phenomenon that erosion rates ebcome larger at a specific threshold point. Third, the equations use readily available data for estimating erodibility values. Fourth, the approach covers continously a wide range of ground cover and foliar cover.

Technical Abstract: Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by applying piecewise regression analysis to predict the differences of erodibility before and after disturbance (i.e., wildfire, prescribed-fire, and tree encroachment) and across a wide range of soil textures as a function of vegetation cover and surface slope angle. The approach combines rain splash, sheet flow and concentrated flow erodibilities into a single parameter for modeling erodibility in most cases. We evaluated the new approach for sites representing different degrees of disturbance associated with burning and tree-encroachment. Our results show that the new erodibility approach in RHEM predicts erosion at the plot scale with a satisfactory range of error in all cases. The new approach extends the applications of RHEM to a greater scope of landscapes and soil texture.