Effects of Surface Coal Mining on Suspended-Sediment Discharge in a Small Mountain Watershed, Fayette County, Pennsylvania

摘要

Data collected in the upper Stony Fork Basin from July 1980 to November 1981 indicate that logging operations associated with block-cut surface coal mining temporarily increased the suspended-sediment discharge of Stony Fork. However, the strip-mining operation did not increase the suspended-sediment discharge of Stony Fork because of effective sediment-control measures. These controls include diversion terraces and a large sediment-control pond. The 50-acre mine site yielded an average of 6.9 tons of sediment per acre, whereas the sediment yield of the 2.5-square-mile study area was 0.13 tons per acre. During most storms, sharp increases in streamflow were accompanied by corresponding increases in suspended-sediment concentrations. At the end of a storm, suspended-sediment concentrations quickly returned to base-flow levels. Instantaneous water discharge ranged from 0.02 to 146 cubic feet per second. Average monthly water discharges ranged from 0.30 to 14.3 cubic feet per second. Suspended-sediment concentration ranged from less than 10 to 905 milligrams per liter. The highest daily mean suspended-sediment concentration was 176 milligrams per liter.