CONTRASTING HYDROCHEMISTRY OF LAKES AND STREAMS ACROSS A SEQUENTIALLY RECLAIMED SURFACE MINE, THE WILDS, SOUTHEASTERN OHIO

Reclamation of surface mining at The Wilds proceeded from north to south and occurred during several revisions of reclamation law. The sequential nature of the reclamation on this former surface mine is reflect by the hydrochemistry of lakes in the northern, middle, and southern subwatersheds. Lakes in the northern subwatershed typically have TDS values between 1200 to 1400 ppm. TDS values in middle subwatershed lakes range between 800 to 1100 ppm and in the southern subwatershed lakes range between 100 to 500 ppm. The pH values of lakes at The Wilds vary between 6.5 and 9.0 and appear to be primarily controlled by the limestone-rich spoil. Groundwater hydrochemistry measured at a spring in the southern subwatershed typically has TDS values between 1500 and 1800 ppm. Water exiting the watershed at its eastern boundary has TDS values of 1085 to1126 ppm and pH values ranging from 7.76 to 8.11.

In an attempt to characterize the total hydrologic system of the reclaimed surface mine, a preliminary study of stream flow measurements and water hydrochemistry was conducted during the fall. Stream flow measurements and water chemistry analysis was conducted at five locations within the overall watershed. One sample location was on a small stream that drains the northern subwatershed. One sample location was on a stream that drains the middle subwatershed and two sample locations were on a small stream and one of its tributaries that drain the southern subwatershed. A sample location was also established at the exit point from the overall watershed. Measured stream flow values varied from 0.0108-0.36725 cubic feet per second across the watershed. The hydrochemistry of streams in the northern, middle, and southern subwatersheds show an opposite trend compared to the lakes. TDS values range from 904 to 1019 ppm in the northern subwatershed. TDS values in the middle subwatershed range from 815 to 1086ppm and from 1190 to 1356 ppm in the southern subwatershed. It appears that varying amounts of groundwater/surface water interactions may explain the contrasting hydrochemistry of lakes and streams at The Wilds.