Base-flow data from 779 sites in Ohio 's coal region were analyzed statistically to relate land use to selected water-quality characteristics. Sites were classified into five categories: unmined (100 percent unmined land), abandoned (50 percent or more abandoned surface mines), reclaimed (50 percent or more reclaimed surface mines), deep-mined (50 percent or more underground mines), and mixed (all others). Specific conductance , pH, alkalinity, acidity, sulfate, dissolved iron, total iron, and total manganese in streams draining basins in the coal region were the eight characteristics selected for analysis. (USGS)