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30 January 2004 AGE-NC Project No 96-0232 Page 7 of 15 3.0. GROUND WATER MONITORING AND SAMPLING On 08, 09 and 10 December 2003, ground water monitoring and sampling were performed at 35 single-ormulti-level ground water monitoring wells(MW-1 through MW-18)and at ten ground water extraction wells(EW-1 through EW-10), in addition,grab water samples were collected from two San Joaquin County service area No 31 municipal water wells (CSA-1 and CSA-2) on 09 December 2003 Quarterly ground water monitoring procedures for the site were outlined in the AGE-prepared Work Plan Addendum, dated 28 January 1998, and approved by the San Joaquin County Environmental Health Department (SJCEHD) by letter dated 24 February 1998 As-built monitoring well construction details are summarized in Table 9 A coordinated effort was made with Three B's Truck Plaza (14749 Thornton Road, Lodi CA) to conduct ground water monitoring activities concurrently, the Three B's Truck Plaza ground water elevation results and analytical results are in Appendix F 3 1 WELL MONITORING AND PURGE PROCEDURES On 08 December 2003, the depth to ground water was measured at each monitoring well from the top of each well casing to the nearest 0 01-foot utilizing a Solinst water level meter The ground water elevation in each monitoring well was calculated by subtracting the measured depth to ground water from the surveyed casing elevation (Table 4) Ground water elevation and vertical gradient data for wells MW-9,MW-11,MW-13,MW-16,MW-17,MW-18 and Three B's Truck Plaza wells MW-6, MW-9 and MW-10 are depicted in cross section C-C'(Figure 3), ground water elevations were plotted for the informal First Zone,Second Zone,Secondary Aquifer Zone and Primary Aquifer Zone hydrogeologic units as defined in AGE's Final Remediation Plan (Figures 4, 5, 6 and 7, respectively) On 08, 09 and 10 December 2003, approximately 5 to 10 gallons of ground water (a minimum of three casing-water volumes per well)were evacuated(purged)from wells MW-1 through MW-7 and MW-16 utilizing disposable polyethylene bailers, approximately 70 to 85 gallons of ground water were purged from wells EW-1 and EW-3 utilizing a two-stage submersible pump Temperature,pH and conductivity were measured for stabilization at regular purge-volume intervals from each well using an Oakton water analyzer Field data and logs are provided in Appendix G The purged ground water was transferred to the ground water remediation system holding tank for treatment and disposal Single-completion monitoring wells MW-14,MW-15,MW-17,MW-18 and multi-level monitoring wells MW-8 through MW-13 were purged utilizing a Watera-Hydro-Lift H pump equipped with a mechanical arm by lowering and raising a 3/8-inch outer diameter, length-discrete polyethylene hose . equipped with a ball-valve water tip through the top chambers into the specific water-charged Advanced GcoEnvironmental,Inc