An evaluation of water-quality data from Hydrologic Accounting Unit 051100, Green River Basin, Kentucky

Streamflow and water quality data collected by the U.S. Geological Survey (USGS) and the Kentucky Natural Resources and Environmental Protection Cabinet from 37 sites in the Green River basin were compared to data from the USGS National Stream Quality Accounting Network (NASQAN) Station, Green River near Beech Grove, Kentucky. This comparison was used to determine variability of water quality data throughout the basin, and to determine if water quality data from the NASQAN station were representative of water quality data upstream. Water quality concentrations, yields, and trends were studied. Water quality data from the NASQAN station were fairly representative conditions throughout the basin for specific conductance, pH, phosphorus and nitrogen, but were not representative for chloride, sulfate, iron, and water temperature. Water quality characteristics which were not representative can generally be attributed to impacts of specific land uses such as coal mining or oil production. Mean concentrations of suspended sediment were similar, but extreme concentrations varied throughout the basin. There were no temporal trends detected in instantaneous streamflow, sulfate, or total iron concentrations. Specific conductance was increasing at three stations and decreasing at one, chloride was increasing at two stations and decreasing at one, phosphorus was increasing at two stations, dissolved iron was increasing at one station and decreasing at one, pH was increasing at three stations and decreasing at two, suspended sediment was increasing at one station and decreasing at one, and water temperature was decreasing at two stations. The NASQAN station had increasing trends in chloride, phosphorus, pH, and suspended sediment, and a decreasing trend in water temperature with time. (Author 's abstract)