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1.AOO1 A S S O C I A T E S I N C will collect one groundwater sample from well MW 1. ATC will also collect one groundwater sample from well MW 1 mid-way through the test and after the 48-hour pump test has been completed. The groundwater samples will be placed on ice and transported under chain-of- custody to a State-certified laboratory. Samples will be analyzed for TPHg and BTEX by EPA method 8015/8020 and for MTBE by EPA Method 8020. If MTBE is detected in any groundwater samples by EPA Method 8020, the sample will be analyzed for oxygenate fuel additives by EPA Method 8260 to confirm the results. A pump equipped with a flow meter, totalizer, and discharge hose will be installed into well MW 1. During the test, ATC will also place transducers in well MW 1 and in observation wells MW2 and MW3 to measure and tabulate the depth to water in observation wells at frequent intervals. A submersible pump equipped with a flow meter capable of reading flows up to 10 gallons per minute (gpm) and a discharge hose will be installed in the groundwater extraction well. ATC will use a generator to supply power to the pump. ATC will perform a three-step drawdown test to determine the optimal flow rate for the 48-hour pumping test. Based on these results, groundwater will be extracted from the well at a constant rate estimated at 5 gpm for a period of 48 hours and discharged directly to the sanitary sewer system, pending approval from the City of Ripon. If the City will not allow direct discharge to the sanitary sewer, ATC will store the extracted water on site until it can be properly disposed of. If the well goes dry during the long-term pumping test, the pumping test will be temporarily halted to allow groundwater to sufficiently recover and the test will be restarted at a lower extraction rate. The pump, discharge hose, and transducers will be removed from the extraction well and the observation wells upon completion of the pumping test. Preparation of Summary Report A summary report will be prepared after the groundwater extraction test is complete. The report will detail results of the 48-hour groundwater extraction test and, based on those results, will make recommendations for site remediation. The report will be prepared in accordance with California Regional Water Quality Control Board (RWQCB) and PHS/EHD reporting guidelines. Schedule The 48-hour groundwater extraction test will be scheduled as soon as regulatory approval of this workplan is received from PHS/EHD and costs for the remedial investigation are approved by the State Cleanup Fund. ATC will notify PHS/EHD at least 48 hours prior to beginning any field activities. The report will be submitted to PHS/EHD approximately four to five weeks after field activities have been completed. W:\14981\REPORTS\WPPUMP.DOC 3