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20 November 1995 <br /> AGE-NC Project No. 95-0152 <br /> Page 2 of 4 <br /> feet below surface grade(bsg). Soil samples were collected from the sidewails and beneath the pit, <br /> and submitted to a state certified laboratory for analysis of TPH-g and BTE&X. The initial five feet <br /> (surface grade to 5 feet bsg) of excavated soil was used to partially backfill the UST excavation <br /> following soil sample collection. <br /> Analytical results of the soil samples indicated that substantial TPH-g and BTE&X constituents were <br /> still present at the sidewalls and beneath the excavation. On 14 November 1995, the excavation was <br /> backfilled to approximately six feet below surface grade(bsg). <br /> t <br /> 2.4. GROUND WATER DEPTH AND FLOW DIRECTION <br /> The water-table surface beneath the site occurs at a depth of approximately 75 feet below surface <br /> grade (bsg). The uppermost ground water flows in an unconfined aquifer. With depth, the aquifer <br /> becomes more confined due to the presence of mixed heterogeneous layers of sediments. <br /> Review of ground water surface elevation contour maps published by the San Joaquin County Flood <br /> Control and Water Conservation District suggests that regional ground water flow is towards the <br /> west. <br /> 3.0. SCOPE OF WORK <br /> 3.1. PROBING AND SAMPLING <br /> The proposed investigation.includes advancing three soil penetrations using"direct push" technology <br /> in the location of the former gasoline UST area. Soil probe locations are illustrated in Figure 2. Soil <br /> penetrations will be advanced to a maximum depth of 65 feet utilizing a van-mounted Geoprobe 5400 <br /> soil probing machine and 1.125-inch rods. <br /> Soil samples will be collected at five-foot intervals beginning at 15 feet below site grade(bsg) using <br /> a Geoprobe soil assembly and associated 1.125-inch diameter brass sleeves. The middle brass sleeve <br /> will be removed and the ends covered with Teflon tape or aluminum sheets, sealed with plastic end <br /> caps, secui ed with tape, and immediately placed in a chilled container for transportation to a State- <br /> certified laboratory. Each sample sleeve will be labeled with the following: boring location, depth, <br /> time, date and sampler's initials. <br /> Soils will be described using the Unified Soil Classification System (USCS). Soil sample descriptions <br /> and PID screening results would be summarized on boring logs prepared for the final report. <br />