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d C Mr. Michael Ilabith 202/799-5045 February 6, 1991 Page 2 from San Joaquin County. The well log for the recovery well Is included In Appendix A. The location of the i. recovery well is indicated on the site plan (Figure 1). The recovery well was developed on November 10, 1990. After surging,water was pumped from the well 3 until it was clear. The well was then surged again, and water was pumped from the well until It was clear. Approximately 60o gallons of water were pumped from the well into a 8,500 gallon storage tank on site, pending disposal. 3,0 AQUIFER PUMP TEST 3.1 PURPOSE:AND METHOD An aquifer pump test was conducted on December 5, 1990. The purpose of the test was to provide an in situ measure of aquifer characteristics around each measuring point,the recovery well efficiency,the radius of influence of the recovery well (cone of depression), the capture zone of the recovery well, and the integrity of the confining layer separating the two aquifers. The test was conducted by pumping from the recovery well at a constant flow rate and measuring the depression of the water table in the recovery well and adjacent monitoring wells. The rate of water table depression determines the transmissivity(a measure i of the ability of watQr to flow through the aquifer)and storativiry(the amount of water released from storage per volume of aquifer)of the aquifer. Direct measurement of water table depression in the monitoring wells determines the radius of influence of the recovery well. The measured transmissivity of the aquifer and the natural groundwater flow direction allows prediction of a"capture zone of the recovery well,or the zone of the aquifer within which the flow direction will be directed toNard the well. If pumping rate and physical parameters are held constant,a higher value for the transmissivety would result in lower drawdown and increased radius of influence. The flow rate from the well was held constant at 19.5 gprn during the test. This flow rate was chosen to ensure adequate drawdown for data interpretation. Groundwater was pumped from the recovery well into two 6,500 gallon storage tanks on site, pending disposal A Ne)rthweet instruments"DataLogger"system was used fo, electronic recording of water depth.A pressure sensitive transducer was paced 10 feet below the water table in monitoring wells MW-4,MW-5,MW-7,and MW-11. Eiach transducer was linked to the DataLogger, where the pressure readings in millivolts were converted to feet of water above the transducer and then stored In memory. Readings were taken at time - Pk CROUNDWATElt TECHNOLOGY,INC.