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I <br /> IMulti-Level Monitoring Well Installation Report - Fourth Quarter 2002 <br /> • CALIFORNIA FUELS CARDLOCK STATION <br /> I2402 Pacific Avenue, Stockton, California <br /> I10. INTRODUCTION AND SCOPE OF WORK <br /> I Advanced GeoEnvironmental, Inc (AGE) has prepared this ground water monitoring well <br /> installation report for 2402 Pacific Avenue (site), Stockton, California The report documents <br /> procedures and results for Installation of one multi-level ground water monitoring well at the site <br /> I during October, November and December 2002 The location of the site is illustrated in Figure 1, <br /> general features at the site are illustrated in Figure 2 <br /> The scope of work of this investigation Included abandonment of original well MW-13 and <br /> installation of a replacement well (multi-level ground water monitoring well MW-13) AGE had <br /> recommended by letter,dated 22 July 2002,that original well MW-13 be replaced with a multi-level <br /> I monitoring well because the integrity of the well casing had been compromised,the proposed multi- <br /> level replacement well would also be able to assess the Impact of petroleum hydrocarbons to deeper <br /> ground water as well as within the original ground water Interval AGE's recommendation was <br /> I approved by San Joaquin County Environmental Health Department(SJCEHD)letter dated 31 July <br /> 2002 (Appendix A) <br /> IBased on previous CPT results detailed in the AGE-prepared Cone Penetrometer Testing Site <br /> Investigation-Fourth Quarter 2001,dated 19 February 2002,and comparison with soil descriptions <br /> from borings previously advanced on the site,AGE has developed a preliminary subsurface model <br /> of the site soil stratigraphy comprised of ten informal zones, a vadose (unsaturated) zone and nine <br /> hydrologic units(Figure 3) Multi-level well MW-13 was screened at a depth of between 95 and 100 <br /> I feet bsg to continue the assessment of Hydrologic Unit 5,and at depths of between 120 and 125 feet <br /> bsg and between 145 and 150 feet bsg to assess the sand layers encountered in Hydrologic Units 7 <br /> and 9, respectively <br /> This report has been prepared in accordance with guidelines issued by the California Regional Water <br /> Quality Control Board(RWQCB)-Central ValleyRegion for investigations of underground storage <br /> tank (UST) sites A summary of A summary of previous Investigations at the site was Included In <br /> the AGE-prepared Corrective Action Plan-May 1998, dated 05 May 1998 <br /> I The following is a brief summary of events for the October, November and December 2002 well <br /> Installation activities performed at the site <br /> • 14 October 2002 - Original ground water monitoring well MW-13 was abandoned by over- <br /> drilling to 100 feet below surface grade (bsg) <br /> • 24 October 2002 - Soil boring for multi-level well MW-13 advanced to <br /> I approximately)52 bsg with no collection of soil samples, the soli boring was completed as <br /> well MW-13A, -13B and -13C (A-C) <br /> Iadvanced CeoEnvironmental,Inc <br /> I <br />