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Evaluation of Potential Well Impacts From <br />The Proposed Nix Property Sand and Grevel Operation <br />' • This leveling effect will create lake surface elevations 2 to 3.5 feet lower than the pre-mining <br />groundwater surface at the upgradient end of Mine Areas 1, 3, 4 and 5 based on September <br />' 14, 2001 groundwater surface observations. <br />• Using the ,Theis non-equilibrium equation, the lake leveling impacts (i.e., reduction in <br />available saturated thickness) to upgradient well owners within 600 feet of the mining azeas <br />can be shown to be generally less than 1 foot, with many welts projected to experience less <br />' than 0.5 foot of reduced saturated thickness. <br />' • Using the Theis non-equilibrium equation, it can be shown that a typical 15-gpm domestic <br />well and a 1,000-gpm irrigation well create 0.2 and 10.6 feet of drawdown, respectively, in <br />'.the aquifer of a distance 1 foot away from the pumping well if pumped continuously for 365 <br />days: <br />' • An increased reduction in saturated thickness of up to 1 foot at these representative domestic <br />and irrigation wells is less than 5 percent of the available saturated thickness at upgradient <br />' locations.' " " <br />' • Lake leveling will create lake surface elevations 2 to 3.5 feet higher than the pre-mining <br />groundwater surface at the downgradient end of Mine Areas 1, 3, 4 and 5 based on <br />' September 14, 2001 groundwater surface observations. <br />• This leveling effect will tend to benefit downgradient well owners by increasing the saturated <br />-thickness in the vicinity of the ponds. <br />C:\011-074\OOOdtl\I mpactsReport.doc <br />' Ot t-074.000 <br />November 2001 <br />Wright Water Engineers, Inc. <br />Page 10 <br />