Scientific Investigations Report 2010–5257
The Fort Cobb Reservoir watershed encompasses about 813 square kilometers of rural farm land in Caddo, Custer, and Washita Counties in southwestern Oklahoma. The Fort Cobb Reservoir and six stream segments were identified on the Oklahoma 1998 303(d) list as not supporting designated beneficial uses because of impairment by nutrients, suspended solids, sedimentation, pesticides, and unknown toxicity. As a result, State and Federal agencies, in collaboration with conservation districts and landowners, started conservation efforts in 2001 to decrease erosion and transport of sediments and nutrients to the reservoir and improve water quality in tributaries.
The U.S. Department of Agriculture selected the Fort Cobb Reservoir watershed in 2003 as 1 of 14 benchmark watersheds under the Conservation Effectiveness Assessment Project with the objective of quantifying the environmental benefits derived from agricultural conservation programs in reducing inflows of sediments and phosphorus to the reservoir. In November 2004, the Biologic, Geographic, Geologic, and Water Disciplines of the U.S. Geological Survey, in collaboration with the Agricultural Research Service, Grazinglands Research Laboratory in El Reno, Oklahoma, began an interdisciplinary investigation to produce an integrated publication to complement this program.
This publication is a compilation of 10 report chapters describing land uses, soils, geology, climate, and water quality in streams and the reservoir through results of field and remote sensing investigations from 2004 to 2007. The investigations indicated that 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. The three major streams flowing into the reservoir contribute nutrients causing eutrophication, but minor streams draining cultivated fields near the reservoir appeared to be disproportionate contributors of nutrients. Increasing conservation practices on small streams may have a greater effect in mitigating eutrophication in the reservoir than additional installation of such measures on the larger creeks.
First posted September 20, 2011
To access PDFs of the individual chapters, use the links listed at the bottom of this webpage.
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Becker, C.J., ed., 2011, Assessment of conservation practices in the Fort Cobb Reservoir watershed, southwestern Oklahoma: U.S. Geological Survey Scientific Investigations Report 2010–5257, 10 chapters.
Report Cover (269 kB)
Chapter 1 PDF (412 kB)
Integrated Science to Support the Assessment of Conservation Practices in the Fort Cobb Watershed, Southwestern Oklahoma
Chapter 2 PDF (712 kB)
Climate of the Fort Cobb Reservoir Watershed, Southwestern Oklahoma, 1940–2007
Chapter 3 PDF (1.26 MB)
Soils, Crop Production, and Geology in the Fort Cobb Reservoir Watershed, Southwestern Oklahoma
Chapter 4 PDF (2.60 MB)
Terrestrial Remote Sensing of the Fort Cobb Watershed, Southwestern Oklahoma
Chapter 5 PDF (762 kB)
Land-Cover Analysis for the Fort Cobb Reservoir Watershed, Southwestern Oklahoma, 2005
Chapter 6 PDF (5.24 MB)
Mapping with Imaging Spectroscopy, Fort Cobb Reservoir Watershed, Southwestern Oklahoma
Chapter 7 PDF (1.33 MB)
Stream-Water Quality, Fort Cobb Reservoir Watershed, November 2004 to May 2007
Chapter 8 PDF (1.54 MB)
Water Quality and Trophic Status of Fort Cobb Reservoir, Southwestern Oklahoma, 2006
Chapter 9 PDF (1.08 MB)
Datasets ZIP (2.45 MB)
A Compilation of non-USGS Environmental Spatial Data, Fort Cobb Reservoir Watershed, Southwestern Oklahoma
Chapter 10 PDF (2.39 MB)
Synopsis of Integrated Science to Support the Assessment of Conservation Practices in the Fort Cobb Reservoir Watershed, Southwestern Oklahoma