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The second pumping test lasted 50 minutes at a pumping rate of 4 gpm before the water level <br /> in the pumping well dropped below the pressure transducer. The third test was performed for <br /> 200 minutes at a pumping rate of 3 gpin. <br /> Data from the third test was analyzed for aquifer parameters. Hydrographs showing the time <br /> drawdown relationship in the observation wells during the third test are presented in <br /> Figure 3-3. A review of the water level response in the observation wells during this pump <br /> test indicates that all observation wells displayed constant or increasing water levels. The <br /> rising water levels may be caused by background water level fluctuations. <br /> Aquifer Parameter Analysis <br /> Data from the aquifer tests were analyzed using two different sets of assumptions. The <br /> response in the pumped well was analyzed assuming that the pumped zone was an isotropic <br /> confined aquifer and that the pumped layer was .a confined leaky aquifer. The cumulative <br /> results from the analyses define reasonable and bounding values for the aquifer parameters. <br /> Confined Isotropic Analyses <br /> } Methods for analyzing drawdown data from a pumping well are limited; most analytical <br /> methods use water level.data from observation wells located some distance from the pumping <br /> well. One exception is the Cooper-Jacob straight line analysis. This method is applicable to <br /> drawdown in the pumping well if it is assumed that well losses are minor compared to the <br /> true drawdown. <br /> Other assumptions inherent in this method include: <br /> i <br /> • The aquifer is homogenous and isotropic. <br /> 4 & The pumped well fully penetrates the aquifer. <br /> 1 0 The aquifer is of infinite lateral extent. <br /> • The aquifer is confined above and below by impermeable layers. <br /> 0 Data used in the analysis are collected at a late enough time such that <br /> 2 <br /> � 0.01 > rS <br /> 4Tt <br /> where <br /> r= the radius of the pumped well <br /> S = the aquifer storativity <br /> T W the aquifer transmissivity <br /> r t= the.time since the beginning of the test <br /> i <br /> Only the last assumption is strictly true of the aquifer system beneath the Disco site. <br /> SF010030982.DOc 3-6 <br />