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00-3737 <br /> Table 2: Groundwater Elevations (feet) <br /> Well/D# Wellhead Depth to Groundwater <br /> Elevation Groundwater Elevation <br /> PES-1 10.581 8.596 1.985 <br /> PES-2 9.921 7.919 2.002 <br /> PES-3 10.355 8.375 1.980 <br /> PES-4 10.433 8.487 1.946 <br /> PES-5 10.478 8.500 1.978 <br /> PES-6 10.000 7.989 2.011 <br /> Measurements relative to an arbitrary datum of 10.000 at PES-6(top of casing) <br /> The groundwater elevation data indicate that Site groundwater flows generally <br /> northeasterly (away from the man-made pond). However, the hydraulic gradient is <br /> so small (4.81 X 10-5 feet/foot, or only about 1/4-foot/mile), it is unlikely there is any <br /> significant flow in the shallow groundwater aquifer. Furthermore, it is likely that <br /> the groundwater flow may change significantly seasonally or due to significant <br /> groundwater recharge (as during rainfall events), possibly even reversing <br /> direction. <br /> 4.0 Limited Subsurface Investigation <br /> 4. 1 Soil Borings <br /> Paragon oversaw the advancement of six soil borings (designated P-1 through P-6) on <br /> July 31 and August 1, 2000 using hollow-stem augers advanced by a truck-mounted <br /> drilling rig. We collected soil samples in a split-spoon driven by a standard 140-pound <br /> drop hammer or hydraulically pushed by the drill rig. Mr. Benson R. Gould of Paragon <br /> supervised the drilling, conducted by our subcontractor Spectrum Exploration, Inc. <br /> (Spectrum) of Stockton, California. We generally followed our standard protocols (see <br /> Appendix D), as modified by PHS-EHD requirements. <br /> Spectrum placed boring P-1 at approximately the location where SGS identified the <br /> greatest PCE concentration. They placed borings P-2, P-3, P-5, and P-6 near the boundary <br /> of the Site, along Shoreline Drive. They placed boring P-4 on the north side of the Site <br /> building, at an inferred upgradient location. Figure 5 illustrates these locations. <br /> 3422 West Hammer Lane,Stockton,California <br /> —7— <br />