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In the Cow Camp and Bond Creek drainages, Wadge spoils aquifer dischazges will <br />contribute flow to these tributary creeks and eventually to Fish Creek. Duting the <br />months of June and July, Cow Camp Creek and Bond Creek sustain flow their entire <br />length to Fish Creek. During this period, each creek contributes water to the <br />associated alluvial aquifers. The spoils spring dischazges aze sufficiently diluted by <br />snowmelt runoff to preclude degradation to the quality of the alluvial aquifers in <br />these drainages. (See the Surface Water section of this Probable Hydrologic <br />Consequences statement for further discussion regazding surface water impacts.) <br />Information supplied by Seneca Coal Company indicates that at their confluences <br />with Fish Creek, Cow Camp Creek and Bond Creek do not support flow during the <br />months of August and September. It is assumed that during this period of time, Cow <br />Camp and Bond Creek flow for about 2 miles beyond the disturbed area boundary <br />before becoming ephemeral. At the point where the streams become ephemeral, it is <br />assumed, for purposes of this discussion, that the flow in each drainage is 0.2 cfs <br />with a TDS concentration of 2500 mg1l. <br />Assuming that the Bond and Cow Camp Creeks alluvial water is tributary to that of <br />the Fish Creek alluvium, Seneca Coal Company performed aquifer tests on the Cow <br />Camp Creek alluvial aquifer to obtain a travel time estimate for the potential salt <br />plume through the alluvial aquifer. These tests resulted in an estimated <br />transmissivity value of 4.1 to 5.6 ftZ/day. Based upon this value, a hydraulic <br />conductivity (K) value of 0.32 feet/day was derived. Using the derived K value, and <br />an assumed effective porosity of 0.30, it was determined that flow velocities within <br />the Bond and Cow Camp Creek alluvial aquifers are 0.15 ft/day and 0.13 ft/day, <br />respectively. Based upon these calculations, it is thought that travel time to Fish <br />Creek within these alluvial bodies is 200 years and 300 years for the Bond Creek <br />alluvium and Cow Creek alluvium, respectively. <br />It would appeaz that the transmissivity range of 4.1 to 5.6 ftZ/day and the calculated <br />travel times aze extremely low for an alluvial system. To verify these calculations <br />and assumptions, Seneca Coal Company has placed a monitoring well in both the <br />Cow Camp and Bond Creek drainages. These wells were placed, completed and <br />monitored in such a manner so that the travel time and velocity predictions made can <br />be verified. Results of the monitoring have not yet been compiled, but will be <br />compiled and included in the revised Probable Hydrologic Consequences section of <br />the permit application package. <br />Seneca Coal Company also performed an aquifer test at a well completed in the Fish <br />Creek alluvium neaz the confluence of Bond and Fish Creeks. This test indicates <br />that the Fish Creek alluvial aquifer is capable of storing and transmitting <br />substantially more water than that of the sub-drainages. Slug injection tests <br />indicated that the transmissivity of this aquifer is about 37.6 ftZlday, while the K <br />value was calculated to be 7.5 ft/day. Therefore, it is thought that the potential <br />impacts to the baseline water quality of the Fish Creek alluvial aquifer, due to the <br />30 <br />