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I a using each of the methods Figures 3 through 8 illustrate the Theis and Cooper-Jacobs • solutions for the data from observation wells MW-7, MW-8 and MW-14 The values using the two methods were in close agreement The values calculated using the Theis method were used in the calculation of theoretical drawdown (s) When the data from the observation wells was plotted, an interesting pattern was observed The observation wells all showed drawdown beginning at different times depending on their distance from the extraction well The drawdown slows and actually reverses at approximately midnight and recharge occurs until approximately 0400 hours At that time drawdown continues and is back to approximately where it was before 0400 hours in the wells by approximately 0500 hours The wells were checked on an hourly basis during the aquifer test and sounding data was recorded All of the wells including the extraction X%ell were observed to have the same pattern We do not know the source of this pulse of water in the wells It may have something to do with delayed water-table response in the unconfined aquifer or with a tidal effect It is conceivable that either or a combination of both of these explanations can account for this anomaly in the groundwater data The curves were fit to the available data ignoring the anomaly The following assumptions are made in using the Theis and Cooper-Jacobs methods flow is in the range of Darcy's Law, water is discharged instantaneously from storage, and the aquifer is homogeneous and isotropic, has a constant thickness and a negligible slope, and is of infinite extent It is also assumed that the pumping well and the observation «ells fully penetrate the aquifer and that the well diameter is infinitesimal (Fetter, 1988) Aquifer T values calculated by the AQTESOLV Model using the Theis method based on the results of the pumping test were for MW-7 data 1,856 95 GPD/ft, for MW-8 data 3,052 6 GPD/ft, and for MW-14 data 3,375 7 GPD/ft Based on an estimated aquifer thickness of 20 feet the K values would range from 92 9 GPD/ft2 to 168 8 GPD/ft' The K values calculated with the pump test data are higher than the values calculated with the slug test data above The true saturated thickness of the unconfined aquifer beneath the site is uncertain because environmental drilling techniques do not necessarily require drilling through the entire saturated zone, for the purpose of providing a reasonable estimate of K a thickness of 20 feet is assumed This corresponds to the below water portion of the slotted interval in EW- 1 of approximately 15 feet, and 10 feet for each of MW-7, MW-8, and MW-14 Calculated S values by the AQTESOLV Model were 1 393 x 10' for MW-7, 3 234 x 102 for MW-8, and 8 908 x 10' for MW-14 It is common to denve S values from short pump tests that are up to two or three orders of magnitudes lower than what is expected in unconfined aquifers because of the effects of delayed drawdowns Specific yield (Sy) for the unconfined aquifer can be approximated by the S values Several scenanos were modeled using the data from the pump test The s values from • Geebpo�tip„��.. Quln t Repon9 944 33 GEWQMS 3