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phase were simulated by subtracting the heads generated at the end of a 10-year <br />"reclamation period" (i.e., no dewatering) from the initial heads simulated during the <br />calibration phase. <br />In addition, sensitivity analyses were conducted to assess the effect of varying selected <br />input parameters and mine dewatering periods on simulated water levels and drawdowns. <br />Results <br />The results of the model simulations indicate that drawdowns produced from dewatering <br />each of the five phases of the Parsons property is not likely to adversely affect the <br />domestic irrigation wells located nearest to the Parsons Mine. The simulations indicate <br />that a drawdown of one to two feet may occur in a limited area in the alluvial sediments <br />within approximately one mile north of the mine site from dewatering (Figures 4 and 7). <br />Model simulations of post-mining operations were evaluated by comparing water levels <br />generated 10 years after mining reclamation activities were completed to the steady state <br />initial water levels developed during the model calibrations process. The results of the <br />simulations suggest that water levels outside the Parsons Mine area within approximately <br />700 feet of the north permit boundary may increase 1 to 2 feet due to post-mining <br />reclamation activities. Simulated heads generally increased by 4 to 5 feet within areas <br />where mine excavations are to be filled with overburden spoils. <br />Sensitivity Analysis and Discussion <br />A sensitivity analysis was conducted to assess how model output variables were affected <br />by varying key input parameters. Aerial recharge and the mine dewatering period were <br />varied, as follows, to observe the simulated effects on drawdowns induced by the Parsons <br />Mine dewatering. <br />• aerial recharge from precipitation was increased to 2.6 inches/year in the alluvial <br />sediments for dewatering through year 15; and <br />• the dewatering period was extended to 20 years. <br />Increasing the recharge to 2.6 inches/year in the alluvial aquifer throughout the 15 year <br />dewatering period did not result in any significant change in the heads or the magnitude <br />of drawdown within the mine site from that observed with 1.3 inches/year of recharge. <br />The increased recharge did significantly reduce the extent of smaller drawdowns (less <br />EnviroGroup Limited 10