TEMPORAL VARIATIONS OF SURFACE-WATER QUALITY IN A RECLAIMED SURFACE MINE, THE WILDS, SOUTHEASTERN OHIO

Surface-water quality at The Wilds, a biological preserve developed on a reclaimed surface mine, varies from north to south. The area was divided into three regions based on an initial survey of water quality during August 2001. TDS values range between 1200 and 1400 mg/L in the northern region, 800 and 1000 mg/L in the middle region, and between 100 and 500 mg/L in the southern region. Nine lakes (two to four lakes within each region) are tested on a weekly basis for pH, TDS (mg/L), conductivity (µS), and water T (°C). The weekly testing started in late August 2001. One lake that is tested weekly in the southern region has anomalous TDS values compared to other lakes in that region. In addition to the lakes, a spring (southern region) and a stream (middle region) are also tested weekly.

Individual lakes in the northern region show the largest variability in TDS compared to lakes in other regions. TDS values in a northern lake vary between 1210 and 1580 mg/L. A representative lake from the middle region varies in TDS values between 1000 and 1100 mg/L. A representative lake from the southern region varies in TDS values between 180 and 220 mg/L. The spring located in the southern region has TDS values that vary between 1630 and 1820 mg/L. During three weeks in October all lakes recorded lower TDS values. The drop in TDS values was larger for the northern lakes (up to 300 mg/L) than the other regions.

The anomalous southern lake suggests that water quality is influenced by the degree of interaction with groundwater. This lake has shown a steady increase in TDS values (735 to 1050 mg/L) from August to December, except for the drop in October. All other lakes in the southern region have low TDS values (100 to 500 mg/L) and variable levels indicating that they are fed primarily by precipitation. The weekly variations in the other lakes with high TDS values could be due to groundwater interaction or a change in biological activity in these lakes during the fall to winter transition. If variations are related to groundwater interactions, there is a lag response between water quality variations in the lakes and precipitation and drought events at the surface as measured at a gauging station 30 km downstream from the study area.