Brush II - Texas State Soil and Water Conservation Board
The Soil and Water Assessment Tool (SWAT) model was used to simulate the effects of brush removal on water yield in 4 watersheds in Texas for 1960 through 1999. Methods used in this study were similar to methods used in a previous study (TAES 2000) in which 8 watersheds were analyzed. Landsat7 satellite imagery was used in the classification of land use, and the 1:24,000 scale digital elevation model (DEM) was used to delineate the watershed boundaries and subbasins. SWAT was calibrated to existing stream gauge flow and/or reservoir storage. Brush removal was simulated by converting all heavy and moderate categories of brush (except oak) to open range (native grass). Treatment or removal of light brush was not simulated. Results of brush treatment in all watersheds are presented. Water yield (surface runoff and base flow) varied by subbasin, but all subbasins showed an increase in water yield as a result of removing brush. Economic and wildlife habitat considerations will impact actual amounts of brush removed.