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D'Appolonia (1977) is an appropriate technique for anolyzing recovery data when the <br />• well-bore drowdown in the well bore is created by pumping over a substantial time <br />as was the case in the D'Appolonia tests. <br />We believe that the most reliable single hole tests are those which involve a <br />substantial pumping period and analysis of the recovery data. A substantial pumping <br />period before recovery begins insures that a cone of drowdown of significant size is <br />created. Therefore, the rate of recovery is influenced by a larger volume of oquifer <br />than if the drowdown in the well bore is created instantaneously (i.e. as in a slug <br />test). For these reasons, the WWLL tests on wells 05-03-0005, I C, PM-7, and 05- <br />01-0010 were performed by pumping 360 min., 131.6 min., 62.1 min., and 30.4 min., <br />respectively, and the recovery data were analyzed to estimate transmissivity. These <br />tests are referred to as drowdown/recovery tests. An instantaneous drowdown or <br />slug test was performed on well 05-01-0004 because the column of water standing in <br />this well was too small to permit prolonged pumping. A slug test was also utilized <br />for we11 OS-01-0010. <br />The classical method of analyzing recovery data following a period of constan <br />rate pumping (i.e. the Theis-Jacob recovery method) yield seriously incorrect value <br />for transmissivity when the afterflow discharge to the well bore during recovery is <br />• a significant fraction of the discharge during the pumping period. Such is the case <br />for each of the tests conducted in this study. The Hvorslev method properly <br />accounts for the afterflow but is theoretically appropriate only if the drowdown in <br />the well-bore is created instantaneously. Therefore, a method reported by <br />McWhorter (1980) was used to analyze the recovery data. Briefly, this method is <br />based upon a superposition of responses resulting from constant oquifer discharges <br />over short time intervals. The discharge over each time interval is constant but may <br />be different from interval-to-interval. Thus the time varying afterflow discharge can <br />be accounted for ina relatively simple manner. <br />The equation used for calculating transmissivity is <br />T = I (O In to + n-1 p.ln n + I - it <br />4n sw (tn) I p in - ip iEl ~ n -~ <br />where i n <br /> <br />Revised 7-81 2.5-52 <br />