Current rangeland erosion prediction technology: rangeland processes handbook: hydrology and soil erosion

Authors: Weltz, Mark; NOUWAKPO, S. KOSSI - University Of Nevada; Williams, Christopher - Jason; Pierson Jr, Frederick; SPAETH, KEN - Natural Resources Conservation Service (NRCS, USDA); Nearing, Mark; Hernandez, Mariano; AL-HAMDAN, OSAMA - Texas A&M University

Submitted to: Agriculture Handbook
Publication Type: Government Publication
Publication Acceptance Date: 9/13/2021
Publication Date: 9/13/2021
Citation: Weltz, M.A., Nouwakpo, S., Williams, C.J., Pierson Jr, F.B., Spaeth, K.E., Nearing, M.A., Hernandez Narvaez, M.N., Al-Hamdan, O.Z. 2021. Rangeland Processes Handbook: Hydrology and Soil Erosion (NRCS Publication No 646, Title 190, Subpart F, No. 646.61). Natural Resources Conservation Service (NRCS). 1-108. Available: https://directives.sc.egov.usda.gov/viewerFS.aspx?hid=47163

Interpretive Summary: The purpose of this series of Rangeland Hydrology Handbooks is to improve the understanding of hydrologic processes and sources and transport mechanisms of sediment in rangeland catchments. Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing soil quality, rangeland health and conservation practice effectiveness. Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolerable before crossing the sustainability threshold. In these ecosystems, concentrated flow processes are indicators of degradation and often warrant the implementation of mitigation strategies. Vegetation lifeform type, distribution, and amount influences both infiltration, runoff, and soil erosion processes. Vegetation and ground cover are the principal environmental attributes that can be manipulated by managers on rangelands and have a direct impact on raindrop splash and concentrated flow erosion processes and rates. At the ecohydrologic level, vegetation and concentrated flow pathways are engaged in a feedback relationship, the understanding of which can help improve rangeland management and restoration strategies. In this Handbook, we review published literature pertaining to rangeland hillslope scale hydrologic and soil erosion processes to: (1) present the fundamental science underpinning ecohydrologic processes, (2) describe raindrop splash and concentrated flow erosion processes, (3) discuss the influence of vegetation on these erosion processes, (4) discuss the influence of management on these erosion processes, and (5) discuss the history and current state of modeling runoff and soil erosion at the hillslope scale on rangelands. The tools to predict soil erosion and detailed user guides are provided in the second Handbook: Rangeland Hydrology and Soil Erosion Processes: A guide for Conservation Planning with the Rangeland Hydrology and Erosion Model (RHEM). The RHEM assessment tool provides information that can be combined with ecological state-and-transition models (STMs) and enhance Ecological Site Descriptions (ESDs). The RHEM assessment tool provides information that can be combined with ecological state-and-transition models (STMs) and enhance Ecological Site Descriptions (ESDs). RHEM is designed to be evaluate and quantify benefits of conservation practices.

Technical Abstract: The purpose of this series of Rangeland Hydrology Handbooks is to improve the understanding of hydrologic processes and sources and transport mechanisms of sediment in rangeland catchments. Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing soil quality, rangeland health and conservation practice effectiveness. Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolerable before crossing the sustainability threshold. In these ecosystems, concentrated flow processes are indicators of degradation and often warrant the implementation of mitigation strategies. Vegetation lifeform type, distribution, and amount influences both infiltration, runoff, and soil erosion processes. Vegetation and ground cover are the principal environmental attributes that can be manipulated by managers on rangelands and have a direct impact on raindrop splash and concentrated flow erosion processes and rates. At the ecohydrologic level, vegetation and concentrated flow pathways are engaged in a feedback relationship, the understanding of which can help improve rangeland management and restoration strategies. In this Handbook, we review published literature pertaining to rangeland hillslope scale hydrologic and soil erosion processes to: (1) present the fundamental science underpinning ecohydrologic processes, (2) describe raindrop splash and concentrated flow erosion processes, (3) discuss the influence of vegetation on these erosion processes, (4) discuss the influence of management on these erosion processes, and (5) discuss the history and current state of modeling runoff and soil erosion at the hillslope scale on rangelands. The tools to predict soil erosion and detailed user guides are provided in the second Handbook: Rangeland Hydrology and Soil Erosion Processes: A guide for Conservation Planning with the Rangeland Hydrology and Erosion Model (RHEM). The RHEM assessment tool provides information that can be combined with ecological state-and-transition models (STMs) and enhance Ecological Site Descriptions (ESDs). The RHEM assessment tool provides information that can be combined with ecological state-and-transition models (STMs) and enhance Ecological Site Descriptions (ESDs). RHEM is designed to be evaluate and quantify benefits of conservation practices.