DEVELOPMENT OF MODELS AND CONSERVATION PRACTICES FOR WATER QUALITY MANAGEMENT AND RESOURCE ASSESSMENTS
Location: Grassland, Soil and Water Research Laboratory
Title: Using SWAT to target critical source sediment and phosphorus areas in the Wister Lake Basin, USA
Submitted to: American Journal of Environmental Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2008
Publication Date: March 1, 2009
Citation: Busteed, P.R., Storm, D.E., White, M.J., Stoodley, S.H. 2009. Using SWAT to target critical source sediment and phosphorus areas in the Wister Lake Basin, USA. American Journal of Environmental Sciences. 5(2):156-163.
Interpretive Summary: Lake Wister is an important reservoir for drinking water and recreation in southeastern Oklahoma. Water quality in the lake has declined due to excess phosphorus and sediment from agricultural areas. The SWAT model was used to identify fields in the lake Wister basin which contribute excessive pollutants. Just 10% of the basin was responsible for 85% of the total pollution. These model predictions were used to identify the best areas in the basin for the implementation of subsidized conservation practices by the Oklahoma Conservation Commission.
Wister Lake is located in the San Bois Mountains in southeastern Oklahoma, USA. The reservoir is primarily used as a water supply and flood storage to over 40,000 residents in the area. Due to high levels of phosphorus and sediment, Wister Lake is listed as a high priority basin for the State of Oklahoma. To help address these water quality problems, the Oklahoma Conservation Commission provided cost share funds for landowners in the basin to implement conservation practices. Approach: The objective of this study was to identify or target agricultural land that contributed disproportional pollutant losses, i.e. critical source areas. Results: Implementing conservation practice in these critical source areas allowed optimal placement conservation practices. The Soil and Water Assessment Tool (SWAT) model was used to identify critical source areas of phosphorus and sediment in the Wister Lake basin. SWAT predicted 57,000 metric tons a year of sediment and 84,000 kilograms a year of total phosphorus from upland areas in the basin. Eighty-five percent of the pollutant load originated from just 10 percent of the basin. Conclusion/Recommendations: This allowed the OCC to identify and contact specific agricultural producers to recruit into their water quality program, which optimized the use of limited cost share funds.