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' } O1 December 2004 AGE-NC Project No 97-0333 Page 4 of 11 " Utilizing a Blue-White Industries F-2000 flowmeter,total flow(totalizer)was recorded between 10 ' March 2004 and 23 June 2004 (Table 5) During this time, the extraction and treatment interim ground water remediation system was in operation for approximately 105 days Based on the total ' of approximately 304,196 gallons of water recorded during this time,AGE estimated that an average 2,897 gallons of water was discharged per day during this time 2 6 MASS-VOLUME REMOVAL CALCULATIONS ' Between 10 March and 23 June 2004, an estimated 12 67 pounds of MTBE was extracted from ground water(Table 5), since the system was initiated on 21 January 2002, a total mass of 246 57 pounds of MTBE has been removed The March 2004 to June 2004 mass-volume calculations of MTBE-impacted ground water extracted from the ground water extraction and treatment system are presented in Appendix C Plots of cumulative ground water pump and treat mass removal trends and influent ground water MTBE concentrations versus time are in Appendix D 3.0. GROUND WATER MONITORING AND SAMPLING On 22 and 23 June 2004,ground water monitoring and sampling were performed at 46 ground water , monitoring points(MW-1 through MW-13) Quarterly ground water monitoring procedures for the ' site were outlined in the AGE-prepared Work Plan Addendum, dated 03 April 2002, prepared by AGE and approved by San Joaquin County Environmental Health Department(SJCEHD)by letter dated 12 April 2002 As-built monitoring well construction details are summarized in Table 6 ' 3 1 WELL MONITORING AND PURGE PROCEDURES On 22 June 2004, 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 2) Ground water elevation and vertical gradient data for wells MW-11, MW-12 and MW-13 are depicted in cross section F-F' (Figure 3), ground water elevations were plotted in plan view for the informal First Zone, Second Zone, Third Zone and Primary Aquifer Zone hydrogeologic flow units as defined in AGE's Cone Penetrometer Testing Site Investigation -Fourth Quarter 2000, dated 07 February 2001 (Figures 4 through 7) On 01 and 02 April 2004, approximately 3 to 4% gallons of ground water (a minimum of three ' casing-water volumes per well)were evacuated(purged)from wells MW-1 through MW-5 utilizing disposable polyethylene bailers,well MW-6 was not monitored due to encountering approximately Advanced GeoEnvironmentai,Inc