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1 <br /> 07 February 1997 <br /> AGE-NC Project No 96-0266 <br /> ' Page 2 of 8 <br /> 2 3 GROUND WATER DEPTH AND FLOW DIRECTION <br /> The estimated depth to ground water at the site is approximately 10 to 15 feet below surface grade <br /> ' (bsg),based on the map entitled Lines of Equal Depth of Water Wells, Fall 1993 published by the <br /> San Joaquin County Flood Control District and Water Conservation District, and information <br /> obtained from the PHS-EHD in monitoring wells at surrounding sites Furthermore, PHS-EHD + <br /> ' records indicate that the highest observed ground water elevation at the property was 10 feet bsg, <br /> measured in 1986 <br /> ' The prevailing ground water flow direction in central Stockton is generally toward the northeast,- <br /> however, <br /> ortheast,however, localized ground water flow direction may vary during winter/summer cycles and tidal <br /> fluctuations Ground water is considered of beneficial use and is utilized for domestic,industrial and . <br /> ' commercial purposes <br /> ' 3 0. PROCEDURES <br /> 3 1 PROBING AND SAMPLING <br /> On 14 November 1996 and 16 January 1997, a total of fifteen soil probe borings (P 1 through P 15) <br /> ' were advanced at the site, under the supervision of the PHS-EHD Two soil probe borings were <br /> advanced in the vicinity the UST located within Building C, six soil probe borings were advanced <br /> in the vicinity the UST removed in 1986, in the City of Stockton right-of-way, three soil probe <br /> ' borings were advanced near the southwestern edge of the site, and tour soil probe borings were <br /> advanced in the vicinity the plating shop on the site Locations of the soil probe borings are <br /> illustrated on Figure 2 <br /> ' All probe borings were advanced using AGE's van-mounted Geoprobe 5400 pi obing machine The <br /> probe borings were advanced to depths of 15 to 20 feet bsg Discrete soil samples were collected in <br /> ' most probe boring at 5-foot intervals beginning at a depth of 5 feet bsg Samples were collected <br /> using a 2 15-inch diameter,two-foot long,piston type sampler loaded with four pre-cleaned 1375- <br /> inch by 6-inch brass sleeves The sampling equipment was washed in an AIconox solution and rinsed <br /> ' with water prior to each sampling run to avoid cross-contamination <br /> ' Upon sample retrieval,both ends of the second brass sleeve were covered with Teflon sheets,capped <br /> and sealed with tape Samples were then placed in a chilled container and transported under chain-of- <br /> custody to McCampbell Analytical, Inc (MAI) in Pacheco, California <br /> 1 <br />