WATER QUALITY VARIABILITY IN TRIBUTARIES OF THE CHEAT RIVER, A MINED APPALACHIAN WATERSHED

摘要

An understanding of the dynamics of metals and other solutes from mine drainage is essential to successful planning and stream remediation in mined Appalachian watersheds. Consequently, we conducted a study designed to quantify the spatial and temporal dynamics of trace metals and other water chemistry variables across a range of mining impairment. Water chemistry was monitored every three weeks in 34 stream segments of the lower Cheat River basin in northeastern West Virginia. Water sampling was conducted regardless of flow levels over a period from May 2002 -October 2003 and produced data on spatial and temporal variation in water temperature, dissolved oxygen, pH, conductivity, alkalinity, acidity, hardness, total dissolved solids, and dissolved concentrations of sulfates, iron, aluminum, manganese, cadmium, chromium, and nickel. Our study produced the following results. 1) Water chemistry was temporally variable in all streams examined; however, variability was generally highest in the moderately impaired streams. 2) Severely impaired waterbodies experienced poorest water quality during periods of extended low flows, whereas moderately impaired streams experienced poorest water quality under a variety of moderate and high flow conditions. 3) Elevated trace metal concentrations (chronic and acute) were common in moderately impaired streams and may provide an explanation for biological degradation in these streams. Our results suggest that water samples must be taken during late winter and late summer seasons in order to properly quantify chemical conditions in moderately impaired streams. Furthermore, full restoration of mining impacted watersheds may not be possible unless remediation approaches target reductions in trace metals and control temporal variability in water quality.