Submitted to: USGS - Scientific Investigations Report
Publication Type: Book / chapter
Publication Acceptance Date: 1/1/2009
Publication Date: 9/20/2011
Citation: Andrews, W.J., Becher, C.J., Steiner, J.L., Daniel, J.A., Garbrecht, J.D. 2011. Synopsis of integrated science to support the assessment of conservation practices in the Fort Cobb reservoir watershed, southwestern Oklahoma. In: Becher, C.J. (ed.). Assessment of Conservation Practices in the Fort Cobb Reservoir Watershed, Southwestern Oklahoma. USGS - Scientific Investigations Report. Available: http://pubs.usgs.gov/sir/2010/5257/. Interpretive Summary: The watershed of the Fort Cobb Reservoir in southwestern Oklahoma was investigated by hydrologists, agronomists, biologists, geologists, and remote-sensing experts of the U.S. Geological Survey (USGS) and the Agricultural Research Service (ARS) of the U.S. Department of Agriculture (USDA). Agricultural activities and vulnerability of soils to erosion have led to water-quality issues, especially sedimentation and nutrient enrichment, in the Fort Cobb Reservoir. Best-management practices, such as conversion of cropland to pastureland, construction of grade-stabilization structures, and increasing no-till practices on cropland were expected to decrease erosion and transport of sediments and nutrients to the reservoir and improve water quality and the health of aquatic ecosystems in tributaries to the reservoir. The USDA in 2003 selected the watershed for study as part of the Conservation Effectiveness Assessment Project to quantify environmental benefits derived from agricultural conservation programs. Staff of the USGS implemented multidisciplinary investigations of land use and water quality in the watershed to augment evaluation of physical, chemical, geographic, and biological indicators of the watershed being implemented by the ARS and other partners. This chapter summarizes and includes additional discussion of information presented in chapters 1 through 9 of the report.
Technical Abstract: The Fort Cobb Reservoir in southwestern Oklahoma is an artificial impoundment constructed by the Bureau of Reclamation for water supplies, flood control, and recreation. Success of best-management practices in reducing inflows of sediments and phosphorus to the reservoir prompted the U.S. Department of Agriculture in 2003 to designate the watershed for study as part of the Conservation Effectiveness Assessment Project to quantify environmental benefits derived from agricultural conservation programs. The U.S. Geological Survey, as part of the Central Region Integrated Science Program, studied land uses, soils, geology, and water quality in the watershed through field and remote sensing investigations in collaboration with the Agricultural Research Service from 2004 to 2007. These investigations indicated that though progress has been made in reducing inflows of sediment and nutrients in the basin, targeting best-management practices to small intermittent streams draining to the reservoir and to the Cobb Creek subwatershed may effectively augment efforts to improve eutrophic to hypereutrophic conditions that continue to affect the reservoir. Multidisciplinary data gathered for this report provide information about interactions between land uses, geologic features, other watershed properties, and eutrophication of a major reservoir that would not otherwise have been provided by more limited investigations of water quality or aquatic ecology.