Analysis of characteristics of simulated flows from small surface-mined and undisturbed Appalachian watersheds in the Tug Fork basin of Kentucky, Virginia, and West Virginia
Hydrologic and climatologic data were collected at 10 small, mined and unmined watersheds in the Tug Fork basin of Kentucky, Virginia, and West Virginia. These data included continuous records of discharge, precipitation, and air temperature. Daily records of sediment concentrations and sediment discharges were also obtained and periodic observations of water-quality data taken. A compilation of all these data is presented. The observed climatic and hydrologic data from these basins were used to calibrate the U.S. Geological Survey Precipitation-Runoff Modeling System for each watershed. The calibrated models of each basin were then used with a set of nearby, long-term climatic data to simulate a long record of stream-flow. A 68-year record of daily streamflow and 57 years of annual peaks were simulated for each site. These simulated records were analyzed to obtain flood-frequency curves, flow-duration curves, mean-annual discharges, and the 7-day, 10-year low flow for each site. The flow characteristics computed from the simulated records of discharge were analyzed graphically and statistically by regression analysis to investigate the degree of relationship and to define the relationship between mining and runoff. For this sample of small basins, peak flows, discharges for 10- and 50-percent flow durations, and mean-annual flows are directly related to percent of drainage area disturbed (measured from aerial photos) and drainage area. Percent of drainage area disturbed is generally a more statistically significant estimator of discharge than drainage area, particularly for peak flows of higher recurrence intervals.