Submitted to: Joint Federal Interagency Sedimentation and Hydrologic Modeling
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2018
Publication Date: N/A
Interpretive Summary: Abstract only
Technical Abstract: In the 1930s, severe drought and lack of proper farming methods resulted in lack of vegetation, which combined with subsequent periods of intense rainfall caused increased erosion and flooding. As a result of the Watershed Protection and Flood Prevention Act 1954, USDA installed 45 reservoirs between 1969 and 1982 in the Little Washita River Experimental Watershed (LWREW), located in central Oklahoma. Over time, these reservoirs lose sediment and flood storage capacity due to sedimentation, with rates dependent on upstream land use and climate variability. In this study, sedimentation rates for 12 reservoirs representing three major land use categories within LWREW were measured based on bathymetric surveys that used acoustic profiling system. Physiographic and climate attributes of drainage area of surveyed reservoirs were extracted from publicly available data sources including topographic maps, digital elevation models, USDA Natural Resource Conservation Service (NRCS) soils, and weather stations databases. The variables were correlated with the reservoir sedimentation rates (ReSR) to determine the major variables controlling sedimentation within the LWREW. Percent of drainage area with extreme slopes, saturated hydraulic conductivity, and maximum daily rainfall event recorded in spring explained most of the variability in ReSR. Results of current reservoir sediment and flood capacities, reservoir sedimentation rates, projected lifespans, and all analyzed variables will be presented. The implications of the results will be discussed. Evaluation of these reservoirs fits into the goal of the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of conservation practices.