Water-quality characteristics and suspended sediment of the Clinch and Powell rivers in northeastern Tennessee, 1989-94

Abstract

The U.S. Geological Survey, in cooperation with the Tennessee State Planning Office, conducted a 4 l/2-year water-quality study in the Clinch and Powell River drainage basins in northeastern Tennessee. An intermittent sampling program was conducted from June 1989 through January 1994. Water-quality samples were collected and analyzed for an upstream site and a downstream site on each river. The upstream sites were near the Tennessee-Virginia State line, and the downstream sites were located on the rivers upstream of Norris Lake. At the upstream sites, fecal coliform bacteria exceeded the water-quality criteria for recreational use in 14 of 40 samples. At the downstream sites, counts exceeded the criteria limits in 2 out of 22 samples. Concentrations of nitrogen and phosphorus compounds were within the range expected for natural surface water. Nutrient discharge did not correlate well to streamflow, rainfall, and seasonal effects. Suspended-sediment discharge at the four study sites was related to streamflow, a rainfall factor, and seasonal effects. Average annual sediment yields among sites were estimated at 97 tons per square mile per year on the Clinch River and 184 tons per square mile per year on the Powell River. Concentrations of calcium, magnesium, sodium, potassium, sulfate, chloride, silica, and fluoride were all measured within the range expected for a natural carbonate system. Instantaneous total-iron concentrations exceeded the U.S. Environmental Protection Agency criteria for fish and aquatic life at the upstream sites in 23 of 28 samples on the Clinch River, and in 38 of 44 samples on the Powell River. At the downstream sites, total iron exceeded the same criteria in 2 of 5 samples on the Clinch River, and in 1 of 4 samples on the Powell River.