An investigation of water quality in the industrialized French Broad River basin of western North Carolina has identified water-quality variations, the extent of man's influence on water quality, and trends in changes in the chemical quality of the river. The study centered on data collected during 1958-77 at the U.S. Geological Survey's station at Marshall, N.C.
The French Broad is a clean river. Only occasionally have concentrations of some trace metals been observed to exceed drinking water standards. However, 58 percent of samples analyzed for fecal coliform bacteria during 1974-77 exceeded criteria levels for bathing waters.
Most water-quality variations are associated with variations in streamflow. Concentrations of constituents transported in solution generally decrease at higher flows, whereas concentrations of materials associated with suspended sediment increase with flow. No correlation between discharge and nutrient concentrations has been observed.
Man's activities in the basin have resulted in deterioration of water quality. In 1958, an estimated 64 percent of the inorganic dissolved-solids load in the river at Marshall was due to man-made pollution, and by 1966, it was 74 percent. As of 1977, water quality had returned to levels of 1958, apparently the result of new waste-water treatment facilities and improved industrial technology.