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<br />5 <br /> <br />Case Studies <br /> <br />Case studies presented herein were selected to provide <br />further insight into the practical application of techniques <br />for pumping test analysis 'under a variety of aquifer system <br />conditions. Each pumping. test discussed has its own <br />unique characteristics; however, commonalities of logic do <br />thread their way through all case studies. Nonleaky arte- <br />sian, leaky artesian, water table, and induced streambed <br />infiltration conditions are covered. <br />Experience has shown that all data are equally important <br />in pumping test analysis. Segments of data should be <br />rejected or filtered out only with due justification such as <br />bad water level records due to a stuck float in an observa- <br />tion well. Early- and late-time drawdown data are equally <br />important; type curves should not be automatically <br />matched to either early or late data without due reason. <br /> <br />NONLEAKY AR'l'ESIAN AQUIFER SYSTEM <br /> <br />A pumping test (see Walton, 1962, pp. 33-34) was <br />conducted on July 2, 1953 at Gridley, Illinois, in Case <br />Study 5.1. A group of fully penetrating village wells was <br />used. In general, 270 ft of clay overlie the 18-ft thick fine <br />sand and some gravel aquifer which is underlain by shale. <br />There are no nearby interfering production wells or aquifer <br />system boundaries. The effects of pumping well 3 were <br />measured in observation wells 1 and 2. Observation well 1 <br /> <br />81 <br />