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hundreth of a foot; discharge measurements were obtained using a <br />• calibrated bucket and a stopwatch. <br />2. Analysis and Results of Aquifer Tests <br />Aquifer tests were performed on the following wells: well <br />GW-N9, completed in the overburden and Dakota coal, well <br />GW-N13, completed in the underburden; well GW-N14, completed in <br />the Dakota coal; and well Gk'-N15, completed in the overburden. <br />The results of these tests are presented on Table 23. The test <br />data and graphs are presented in Appendix F. <br />Monitor well GW-N14 was slug tested using the method of Cooper, <br />Bredehoeft, and Papadopulos (Lohman, 1972). This test provides <br />an evaluation of the transmissivity over the slatted interval <br />of the well. A known volume "slug" of water was instantane- <br />ously introduced to the well and the water level recovery was <br />• observed. Values of Sw/So were plotted on the linear scale of <br />semi-logarithmic graph paper and time (t) on the logarithmic scale. <br />The symbol, So, corresponds to the starting head value after the <br />slug at time zero; the symbol, Sw, corresponds to the head at any <br />time t. The data curve is then superimposed on top of a type curve <br />(Plate 2, Lohman, 1972) until a best fit is achieved. The <br />transmissivity is then determined from the following equation: <br />1.0 rc2 (1) <br />T t <br />where: <br />T = Transmissivity (ftz day-1 ) <br />rc = Radius of casing interval over which the water <br />level fluctuates (ft) <br />t =Time (days} <br />. Monitor wells GW-N9, N13, and N15 were analyzed using the modified <br />slug techniques outlined by McWhorter (1982). Briefly, the <br />79 <br />