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' 04 November 2002 • AGE-NC Project No 00-0764 ' Page 3 of 5 pack and hydrated Afterwards,the remaining annular space was backfilled to within six inches of ' surface grade with portland cement,and a traffic-rated well box(8-inch diameter)was installed over each well in accordance with San Joaquin County regulations Monitoring well design specifications are depicted in Appendix B 2 4 GROUND WATER DEVELOPMENT AND SURVEY ACTIVITIES ' d water well development activities were performed at the site in order On 23 August 2002, groan p to increase water flow into the well and to minimize the amount of fine-grained sediment drawn into ' the well during pumping or bailing ' The water level and the total well depth in each monitoring well were measured relative to the tops of the well casings using a Solinst water level meter After water levels and total depths were measured, a steel bailer was used to purge five gallons from each wells casing Then a two-stage ' PVC pump was used to remove 13 to 20 gallons of water from the wells Temperature, pH and conductivity of the purged water were measured at one-gallon intervals using an Oakton water analyzer during purging, the values had generally stabilized by the end of the purging process Ile (Appendix C) Purged water was stored on-site in 55-gallon,Department of Transportation-approved drums ' A California state-licensed survey engineer from Baumbach&Piazza Inc surveyed a reference point on the top of each ground water monitoring well casing at the site to the nearest 0 01-foot relative to the City of Stockton Bench Mark No HS0341, at 14 47 feet above mean sea level (MSL) The ' surveying report (Baumbach & Piazza) is presented in Appendix C ' 3.0. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data collected on ' 23 August 2002, the contaminant impact to soil and ground water was quantified by the laboratory analytical data 1 3 1 STRATIGRAPHY AND DEPTH TO GROUND WATER ' Silt, with a tan, brown or gray color, apparently depending on hydrocarbon impact, was generally encountered from a depth of approximately 5 feet to 35 feet bsg in the shallow well borings, the coarsest material was silty sand,collected at a depth of 25 feet bsg in boring MW-2 Generallypoorly graded sand and silty sand was encountered between 60 and 75 feet bsg in boring MW-5 The soil borings are depicted in Appendix A Advanced GeoEnvironmental,Inc �