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3.0 PUMP TEST Three wells will be tested:VM-9,VM-10 and VM-2,and the results from each well will be compared to determine the most efficient pump rates that will initially be used during remediation. At least two non-pumping wells, including one or more of the existing monitoring wells,will be used as observation wells to measure the drawdown, making it possible to determine.impor ax:: aquifer parameters such as hydraulic conductivity and specific yield. Transducers will be placed.in the observation wells and used to measure drawdown during the test. In addition,water samples obtained during the test will aid in establishing the equipment necessary to effectively treat the water before discharging to the city sewer system. We propose to conduct the test'in two phases.The first phase will consist of a stepped- rate test to determine an appropriate rate for a constant-rate test during the second phase. A 5-10,000 gallon holding tank will be mobilized to the site and will be used to store the extracted water. S3CEHD will be notified 48 hours prior to the start of the test. The procedures of the test are as follows: 1. Each well will be tested separately and the initial pumping rate will be 3 gallons per minute(GPM).The rate will be increased periodically in increments of { approximately 1-2 GPM until the maximum yield is achieved or the maximum flow rate of the pump is reached. This rate will then be used in the constant-rate test,which will continue until the drawdown has stabilized or become asymptotic. E The estimated duration of the test is between 24 and 48 hours. At the end of the test the recovery rate will be measured over a 1 to 2 hour period.- 2. A minimum of three water samples will be collected from the pump stream for laboratory analysis during the test. The samples will be analyzed for TPH as gasoline by EPA method 8015,and BTEX. The results will measure the changes in concentration that occurred during the test. To satisfythe City of Stockton Sanitation District selected samples will be analyzed for volatile hydrocarbons by EPA method 8260 and oxygenates. 3. We estimate from 10,000 to 30;000 gallons of water will be removed. Periodically,the extracted water will be pumped into a vacuum truck and disposed.of at In-Strat,Inc.,.a licensed water treatment company in Davis, California. At the end of the test,the holding tank will be removed. 4. VM-2 has already undergone some tests that suggest that the yield on this well is low and thus will be tested using a low flow(.5-1.5 GPM)pneumatic pump. The well construction and its location suggest that it may yield high concentrations of contamination,relative to the volume of liquid pumped. This well will be tested over a period of 5 to 7 days. 1 i 2 r