Relations among land cover, streamflow, and water quality in the North Canadian River Basin near Oklahoma City, Oklahoma: 1968-2009

The U.S. Geological Survey, in cooperation with the city of Oklahoma City, has collected water-quality samples at the North Canadian River near Harrah, Oklahoma (the Harrah station), since 1968, and the North Canadian River at Britton Road at Oklahoma City, Oklahoma (the Britton Road station), since 1988. The North Canadian municipal wastewater-treatment plant, managed by the city of Oklahoma City, is the largest wastewater-treatment plant in the North Canadian River Basin and discharges effluent between the Britton Road and Harrah stations. Water-quality constituent concentrations were summarized, and trends in concentrations and frequencies of detection of selected constituents with time were evaluated to determine if changes in land cover, streamflow, and other potential sources of constituents in water had significant effects on water quality in the North Canadian River downstream from Oklahoma City.