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ARS Home » Pacific West Area » Reno, Nevada » Great Basin Rangelands Research » Research » Publications at this Location » Publication #358242

Title: Rangeland hydrology and erosion handbook: the RHEM guide

Author
item Weltz, Mark
item Hernandez, Mariano
item Nearing, Mark
item SPAETH, KEN - Natural Resources Conservation Service (NRCS, USDA)
item Pierson Jr, Frederick
item Williams, Christopher - Jason
item AL-HAMDAN, OSAMA - Texas A&M University
item NOUWAKPO, S. KOSSI - University Of Nevada
item Armendariz, Gerardo
item WEI, HAIYAN - University Of Arizona
item Goodrich, David - Dave
item GUERTIN, PHILLIP - University Of Arizona
item Unkrich, Carl
item Polyakov, Viktor
item MCGWIRE, KENNETH - Desert Research Institute
item Nesbit, Jason
item FRAZIER, GARY - Retired ARS Employee
item JOLLEY, LEONARD - Retired Non ARS Employee
item STONE, JEFF - Retired ARS Employee

Submitted to: Agriculture Handbook
Publication Type: Government Publication
Publication Acceptance Date: 9/13/2021
Publication Date: 9/13/2021
Citation: Weltz, M.A., Hernandez Narvaez, M.N., Nearing, M.A., Spaeth, K.E., Pierson Jr, F.B., Williams, C.J., Al-Hamdan, O.Z., Nouwakpo, S., Armendariz, G.A., Wei, H., Goodrich, D.C., Guertin, P., Unkrich, C.L., Polyakov, V.O., McGwire, K., Nesbit, J.E., Frazier, G., Jolley, L., Stone, J. 2021. Rangeland Hydrology and Erosion Handbook: The RHEM Guide (NRCS Publication No 647, Title 190). Natural Resources Conservation Service (NRCS). 1-80. Available: https://directives.sc.egov.usda.gov/viewerFS.aspx?hid=47163

Interpretive Summary: 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. Hydrologic and erosion processes are different on rangelands than croplands due to much higher levels of heterogeneity in soil and plant properties and the consolidated nature of the soils. The purpose of this Handbook is to improve the understanding of hydrologic processes and sources and transport mechanisms of sediment in rangeland catchments at the scale of the hillslope. The first Handbook, Part 646 Rangeland Hydrology and Soil Erosion Processes, provides a review of relevant rangeland hydrology literature on what is known about the impact of range management practices and field experiments conducted across the western United States. This Handbook, Part 647–The RHEM Guide, provides the background for understanding how to use the Rangeland Hydrology and Erosion Model (RHEM) and understand its output for making informed decisions before implementing new management actions. The RHEM model is a newly conceptualized, process-based erosion prediction tool specific for rangeland application, based on fundamentals of infiltration, hydrology, plant science, hydraulics, and erosion mechanics. The model is event-based and was developed specifically from rangeland data. The erosion prediction tool 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. The data drawn on to develop and validate the RHEM series of tools contains over 2,000 rainfall simulation plots and 100 plant communities collected over the last 40 years across the western United States by the Agricultural Research Service and the Natural Resources Conservation Service. These data can be used to understand ecological processes when combined with the RHEM tools to provide sound science when making critical land management decisions. The RHEM assessment tool provides information that can be combined with state and transition models and enhance Ecological Site Descriptions. The RHEM assessment tool has been incorporated into the Automated Geospatial Watershed Assessment (AGWA) tool for understanding and predicting hydrologic and soil erosion processes at the watershed scale.

Technical Abstract: 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. Hydrologic and erosion processes are different on rangelands than croplands due to much higher levels of heterogeneity in soil and plant properties and the consolidated nature of the soils. The purpose of this Handbook is to improve the understanding of hydrologic processes and sources and transport mechanisms of sediment in rangeland catchments at the scale of the hillslope. The first Handbook, Part 646 Rangeland Hydrology and Soil Erosion Processes, provides a review of relevant rangeland hydrology literature on what is known about the impact of range management practices and field experiments conducted across the western United States. This Handbook, Part 647–The RHEM Guide, provides the background for understanding how to use the Rangeland Hydrology and Erosion Model (RHEM) and understand its output for making informed decisions before implementing new management actions. The RHEM model is a newly conceptualized, process-based erosion prediction tool specific for rangeland application, based on fundamentals of infiltration, hydrology, plant science, hydraulics, and erosion mechanics. The model is event-based and was developed specifically from rangeland data. The erosion prediction tool 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. The data drawn on to develop and validate the RHEM series of tools contains over 2,000 rainfall simulation plots and 100 plant communities collected over the last 40 years across the western United States by the Agricultural Research Service and the Natural Resources Conservation Service. These data can be used to understand ecological processes when combined with the RHEM tools to provide sound science when making critical land management decisions. The RHEM assessment tool provides information that can be combined with state and transition models and enhance Ecological Site Descriptions. The RHEM assessment tool has been incorporated into the Automated Geospatial Watershed Assessment (AGWA) tool for understanding and predicting hydrologic and soil erosion processes at the watershed scale.