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t <br /> 17 <br /> GOLDEN GRAIN COMPANY <br /> December 21, 1989 <br /> 202/799-5045.05 <br /> obtain optimum results from slug tests in relatively high- <br /> transmissivity aquifer mai.erials. <br /> An inert plastic slug, 1.312 inches in diameter by 128.5 <br /> inches long, with a volume of 0.1039 cubic feet, was used for the <br /> test in all o£ the wells. A test in which the slug was immersed <br /> s in the water (slug-in test) and one in which the slug was <br /> withdrawn from the water (slug-out test) were performed in each <br /> well. Before the slug was withdrawn for each slug-out test, <br /> water levels were carefully monitored to assure that they had <br /> fully equilibrated after the slug had been introduced. <br /> The data recorded during the slug tests were downloaded into <br /> a computer database at GTI's Concord office for analysis. Plots <br /> of fractional water level recovery (H/HO) versus time on a <br /> logarithmic scale were compared with "type" curves developed by <br /> ---�_ Papadopulos et. al. (1973), as implemented in the "Graphical <br /> Well Analysis Package" (GWAP) software designed by Groundwater <br /> Graphics, of San Diego, California. <br /> During the tests on wells MW-10 through MW-14, the water <br /> levels in the wells recovered to within 95 percent of the <br /> original static level within leso than one minute of slug <br /> introduction or withdrawal. In monitor well MW-7, 95 percent <br /> recovery took nearly 4 minutes. These are rapid recovery times <br /> and indicate high-permeability materials in the subsurface. <br /> Due to the rapid response of the formation to slug <br /> introduction in monitoring wells MW-10 through 14W-14 and <br /> complications with wetting of the unsaturated portion of the sand <br /> 10nPapadopulos, s•s• ' J. <br /> D.slug and inn Water Res <br /> nources <br /> On--the analysisOf _ g test data- <br /> Research, 9, pp. 1087-1089. <br /> GROUNDWATER <br /> TEcuN,0LOGY.INC. <br /> .y <br />