Submitted to: International Soil and Water Conservation Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/12/2017
Publication Date: N/A
Interpretive Summary: Abstract only.
Technical Abstract: The Washita River Basin (WRB) was one of eleven pilot watershed projects selected for construction of flood control reservoirs around the country as a result of the Flood Control Act of 1936. These reservoirs were implemented to prevent and manage soil erosion and flooding. A total of 45 reservoirs were installed between 1969 and 1982 in the Little Washita River Experimental Watershed (LWREW) within the WRB. Evaluation of these reservoirs fits into the goal of the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of conservation practices. Over time, these reservoirs have lost water holding capacity due to sedimentation whose rates depend on land use changes and climate variability. In this study, we measured sedimentation rates for 12 reservoirs which were selected to represent dominant land uses within the watershed. Bathymetric surveys were carried out using a state-of-the-art acoustic profiling system. Bathymetry data were processed and the current water volumes were computed using ArcGIS. Reservoir sediment volumes since impoundment were determined as the difference between reservoir capacity at impoundment and the current capacity. Reservoir sediment volumes were normalized by the contributing area and divided by the number of years to determine rates. Results indicated that sedimentation rates varied from 181 m3/km2/year to 873 m3/km2/year. Future work seeks to determine topographic, landuse, soils, and climate factors that significantly influence reservoir sedimentation rates in the LWREW.