Submitted to: Oklahoma Academy of Science Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2011
Publication Date: N/A
Citation: N/A Interpretive Summary: This research identified portions of two watersheds which contribute disproportionately large amounts of sediment. These locations are priority areas for the establishment of government subsidized conservation measures. Two Oklahoma watersheds were simulated using Soil and Water Assessment Tool (SWAT) and Water Erosion Prediction Project (WEPP) Roads. A small portion of each watershed produced a very large amount of sediment. The identification of these areas may allow conservation programs to be more effective by placing practices where they are needed most.
Technical Abstract: Several state and federal conservation programs provide financial assistance or benefits for landowners who remove cropland from production or implement soil and water conservation measures. Due to limited funding, only a small fraction of a watershed can be included in such programs. The goals of this project were to: (1) Define priority areas in which landowners would be given first access to available funds, or to target specific fields for recruitment into conservation programs, (2) Evaluate the sediment contribution from county roads and target specific road segments for improvement. Two Oklahoma basins were considered, Stillwater Creek and Cobb Creek. Land cover data for both basins were derived from 2001 LandSat TM+ imagery. Both basins were modeled using Soil and Water Assessment Tool (SWAT) and Water Erosion Prediction Project (WEPP) Roads. SWAT model results for sediment were extrapolated to a 30 meter grid for each basin using the original soils, land cover, and Digital Elevation Model themes. This grid was used to target the 5 percent of the of the basin with the greatest sediment yield, which accounted for 31 percent and 75 percent of the total sediment load for the Fort Cobb and Stillwater Creek Basins, respectively. Visits to fields marked as priority areas visually corroborated that the model was targeting highly erodible fields. Likewise road segments predicted to have high erosion were visually corroborated. Responses from the local conservation personnel and landowners to the targeting maps were positive. The identification of critical source areas at the watershed scale may enable conservation programs to place practices where they are need most.