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Aquifer tests performed in the Wadge Coal seam indicate that the Wadge aquifer exhibits a semi-confined condition with a transmissivity value of 377.1 gallons per day per foot (gpd/ft). Wadge water levels, dependent upon well proximity to the recharge area, show some seasonal variation. The quality of the undisturbed Wadge aquifer (well GW-S44) is a calcium/magnesium bicarbonate type, with an average TDS value of 490 mg/1. Well GW-519, which is down-gradient of mining, exhibits a sodium sulfate water type with an average TDS concentration of 855 mg/1. Peabody Coal Company has committed to completing an additional Wadge Coal monitoring well, in the southeastern portion of the permit area, during the 1987 field season. There are three alluvial aquifer systems present within the Seneca II permit area: the Grassy Creek alluvial aquifer, the Cow Camp Creek alluvial aquifer system (drainage from below 004 pond to Fish Creek), and the Bond Creek alluvial aquifer (drainage from below 007 pond to Fish Creek). The Fish Creek alluvial aquifer is not within the Seneca II permit area, but may be affected by water discharging from the permit area. Currently, the Grassy Creek alluvial aquifer and the Cow Camp. Creek alluvium are monitored by 6 wells which are used to monitor depth-to-water and water quality. In order to quantify the effects of mining to the Bond, Cow Camp and Fish Creek alluvial aquifers, Peabody Coal Company has committed to completing two alluvial wells: one in the Cow Camp Creek drainage, and one in the Bond Creek drainage (Exhibit 7-2) during the 1987 field season. These wells will be added to the approved ground water monitoring program and will be placed in such a manner so as to intercept any TDS plume which may migrate through the alluvial aquifers toward the Fish Creek system. The resaturation of portions of the backfilled pits has been expressed as spoils aquifers. Water, through various proposed mechanisms, percolates through the replaced spoils materials and flows down-gradient (topographic) until it reaches the lower-most highwall. When the elevation head of the spoils aquifer exceeds the ground surface elevation, the spoils water discharges in the form of springs, at the topographically lowest point along the reclaimed highwall. Five spoil springs have been identified and are being monitored by Peabody Coal Company. In addition, Peabody Coal Company monitors six spoils wells as part of the approved monitoring plan. In order to further quantify and define the impacts of mining to the hydrologic system, Peabody Coal Company has committed to completing eight spoils wells by the end of 1988. The locations of these spoils wells will be mutually determined by Peabody Coal Company and the Division prior to construction. The quality of the spoils water usually exhibits elevated concentrations of sulfate, manganese, and magnesium. TDS concentrations are variable, but average values upwards of 3,000 mg/1 are not uncommon from spoil well samples, while spoils springs exhibit TDS concentrations which are much lower, usually -14-