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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED INVASIVE SPECIES CONTROL, REVEGETATION, AND ASSESSMENT OF GREAT BASIN RANGELANDS

Location: Great Basin Rangelands Research

Title: Simulating the effect of brush management on runoff and erosion on the Walnut Gulch Experimental Watershed

Authors
item Goodrich, David
item Nearing, Mark
item Guertin, Phil -
item Hernandez, Mariano -
item Levick, Lainie -
item Burns, Shea -
item Jolley, Leonard -
item Weltz, Mark

Submitted to: Government Publication/Report
Publication Type: Government Publication
Publication Acceptance Date: October 1, 2012
Publication Date: December 1, 2012
Repository URL: http://WWW.NRCS.USDA.gov/INTERNET/FSE_DOCUMENTS/STelprdb108287.pdf
Citation: Goodrich, D.C., Nearing, M.A., Guertin, P., Hernandez, M., Levick, L., Burns, S., Jolley, L., Weltz, M.A. 2012. Simulating the effect of brush management on runoff and erosion on the Walnut Gulch Experimental Watershed. CEAP Science Note.

Interpretive Summary: The Conservation Effects Assessment Project (CEAP)-Grazing Lands national assessment is designed to quantify the environmental effects of conservation practices on U.S. non-Federal grazing lands. The assessment includes science-based estimates of expected environmental effects of installed conservation practices using environmental models. Grazing lands are the most dominate land cover type in the United States with approximately 311.7 Mha being defined as rangelands. Information on the type, extent, and spatial location of land degradation on rangelands is needed to inform policy and management decisions on rangelands. This report focuses on the status of hydrologic tools to assess the impact and benefits of conservation practices at the watershed scale using the capability of the AGWA interface and the SWAT river basin and KINEROS2 models. As part of this effort, scientists with the CEAP Grazing Land Team simulated the impact of brush removal and grass seeding on brush-infested rangeland in southeastern Arizona on the Agricultural Research Service Walnut Gulch Experimental Watershed. It was assumed that the entire watershed area was successfully converted to grassland. Simulations were performed using the 5 year 30 minute rainfall event. Results indicated large decreases in peak flow (mm/hr), peak sediment yield (kg/s), and average annual runoff (m3/s) after the watershed was converted to grassland. Peak flow in the channels after conversion to grassland was reduced by 72 to 98 percent, with similar reductions in average annual runoff and sediment yield. This type of analysis provides land managers with the ability to determine which areas are better suited for land cover modification for management purposes such as brush management for fire control or grazing land improvement as well as the spatial location and magnitude of the consequences of the conservation practices.

Technical Abstract: The Conservation Effects Assessment Project (CEAP)-Grazing Lands national assessment is designed to quantify the environmental effects of conservation practices on U.S. non-Federal grazing lands. The assessment includes science-based estimates of expected environmental effects of installed conservation practices using environmental models. Grazing lands are the most dominate land cover type in the United States with approximately 311.7 Mha being defined as rangelands. Information on the type, extent, and spatial location of land degradation on rangelands is needed to inform policy and management decisions on rangelands. This report focuses on the status of hydrologic tools to assess the impact and benefits of conservation practices at the watershed scale using the capability of the AGWA interface and the SWAT river basin and KINEROS2 models. As part of this effort, scientists with the CEAP Grazing Land Team simulated the impact of brush removal and grass seeding on brush-infested rangeland in southeastern Arizona on the Agricultural Research Service Walnut Gulch Experimental Watershed. It was assumed that the entire watershed area was successfully converted to grassland. Simulations were performed using the 5 year 30 minute rainfall event. Results indicated large decreases in peak flow (mm/hr), peak sediment yield (kg/s), and average annual runoff (m3/s) after the watershed was converted to grassland. Peak flow in the channels after conversion to grassland was reduced by 72 to 98 percent, with similar reductions in average annual runoff and sediment yield. This type of analysis provides land managers with the ability to determine which areas are better suited for land cover modification for management purposes such as brush management for fire control or grazing land improvement as well as the spatial location and magnitude of the consequences of the conservation practices.

Last Modified: 7/28/2014
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