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RNAL RSWEDiATM PLAN 14800 West Frontage Road Manteca California 2.8 A uifer Analysis Test Rising head tests (slug tests) were performed in monitoring wells MW-4 and MW-7 on July 3, 1991, to estimate the hydraulic conductivity (K) of the water-bearing horizon in the immediate vicinity of the monitoring wells In preparation for the test, a pressure transducer was placed in the selected well and connected to an "Aqua Star" datalogger which recorded the changes in water level over time The test consisted of dropping a 5-foot-long, 3-inch-diameter PVC pipe (slug), capped at both ends and filed with clean sand, into the well and allowing the water level in the well to stabilize The slug was then quickly removed from the well and the changes in the water level recorded until such time as the water levels in the well stabilized (rising head) A software package entitled "Agtesoly" (Geraghty and Miller Inc , 1989) was used to analyze the data Aqtesolv consists of a curve drawing and matching program The data is analyzed by plotting the time and change in groundwater elevation on the appropriate log or semi-log paper, then matching the data with the appropriate published "type curves." The method of analysis depends on site-specific hydrogeologic conditions, both man-made and naturally occurring The method used to analyze the data at the subject site was the Bouwer and Rice slug test method for unconfined aquifers (Bouwer, et al , 1976) The values for K ranged from 1 5 x 10' to 9 7 x 10' feet per minute (ft/mm) The data and assumptions made in analyzing the data are included in Appendix F I The method used to analyze the potential pumping rate of the aquifer (Q) was the Duput equation (Duput, J , 1863) The values for Q ranged from 0 05 to 6 04 gallons per minute (gpm) The data and assumptions made in analyzing the data are included in Appendix F 3.0 FINAL REMEDIATION PLAN 3.1 Remedial Action Technology Selectlon IThe selected remediation technologyfor this site will remove and destroy petroleum hydrocarbons from both soil and groundwater by using an internal combustion (IC) engine, a power take off, a vacuum pump, air compressor, and a water pump Petroleum hydrocarbons in soil will be removed by vapor extraction Groundwater extraction will create a cone of depression on the groundwater surface, ensuring containment and recovery of the hydrocarbons in groundwater, and also exposing additional soil to the vapor extraction system 90-097A FRP -7-