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T <br />• sw <br />Qp <br />in <br />ip <br />i <br />transmissivity <br />drawdown in well <br />constant pump discharge <br />time since pumping began to end of the nth recovery invervol <br />pumping time <br />index of recovery interval <br />During the test, the pump discharge Op was measured. After cessation of <br />pumping, the drawdown s~,,~ was measured as a function of time until recovery was <br />approximately 90 percent complete. The next step was to plot The drawdown as a <br />function of time on coordinate paper and to divide the recovery period into n equal <br />time intervals. The average afterflow discharge for each interval was calculated <br />from <br />pi=Ae ~swi <br />p t <br />where p s,Ni is the difference in drawdown over the time interval i and Ae is <br />the net area of the casing after subtracting the area of the pump discharge line and <br />• the ores of the power cable. The computations indicated in the formula for <br />transmissivity were carried out to yield values for T. <br />The exhibit on the following page shows the slug test date for Well No. 05- <br />01-0010 superimposed on Cooper, et al., (1967) type curves. The computation of <br />transmissivity is shown in the exhibit. In principal, this type curve method permits <br />estimation of storage coefficient. Storage coefficients obtained by this method ore <br />not particularity reliable. In fact, no single hole aquifer test provides reliable values <br />of storage coefficient and for this reason, no storage coefficients ore reported in <br />Table 2.5-13 for the single hole tests. <br />The use of The foregoing algebraic method is demonstrated using the data for <br />Well No. OS-03-0005. This well was pumped for 360 minutes before recovery began. <br />Recovery was monitored for 1,207 minutes, making the total test time equal to 1,567 <br />minutes. The recovery interval from t 360 tot 1,560 minutes was divided into <br />24 equal intervals of 50 minutes duration. The mean afterflow discharge in each <br />interval was calculated and the transmissivity calculated os: <br /> <br />Revised 7-BI 2.5-53 <br />