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Q = KiA <br />where: <br />Q =Volumetric discharge IL'/tl per unit aquifer width; <br />K =Hydraulic conductivity IL/tl value; <br />i = Hydraulic gradient IL/LI values measured for each aquifer in the expansion area; and <br />A =Saturated area perpendicular to flow IL~I on upgradient pit walls. <br />Units of length are denoted by ILI, and Itl denotes units of time. Assumptions inherent in <br />Darcy's Law include aquifer homogeneity, aquifer anisotropy, and steady-state, laminar flow. <br />The use of Darcy's law for ground water flow calculations into the open pits presents liberal <br />discharge estimates because equation variables are based on: <br />• upgradient pits (i.e., pits "in water" for McWhorter analysis) being saturated across their <br />entire lengths; <br />• upgradient pits being open for the entire year; <br />• no temporal head loss due to pit pumpage; <br />• flow perpendicular to pit lengths; and <br />• saturation areas based on water-level data from wells immediately down-dip from the <br />mine area [overburden saturation appears to increase rapidly in a down-dip direction (dip <br />direction refers to coal seamlJ. <br />As can be seen in Table 17-31, the lowest pit inflows far the Wadge ground water systems in <br />the Seneca II-W South area will occur during the year 2000. These low inflows are based on <br />the excavation of a single pit. The highest estimated inflows associated with the South area <br />Wadge mining are predicted to occur during the years 2001 and 2002. Maximum pit inflow <br />volumes for the confined/unconfined flow system are estimated to vary between 602,784 <br />gallons per year [Igal/yrl (1,651 gal/day(] and 1,406,819 gal/yr (3,854 gal/day(. <br />89 Revised 1 /02 <br />