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1 3-1 <br /> 3.0 INVESTIGATION RESULTS <br /> The following chapter summarizes the results of the Phase II Investigation <br /> 3 1 SUBSURFACE CONDITIONS <br /> The descriptions of subsurface conditions at the TCS, Inc facility as described herein are <br /> based upon an interpretation of site-specific data gathered by Remcor (boring advancement, <br /> soil sampling, monitoring well installation and sampling, a single-well hydraulic test, and <br /> ground water elevation measurements) and regional information obtained from literature 3 <br /> 311 Geology <br /> The Tracy area is located on the west side of the San Joaquin Valley Geomorphic Province <br /> The stratigraphic units that occur in the Tracy area are members of the Great Valley <br /> Sequence of water lam continental and marine sediments Most of the continental rocks and <br /> deposits in the Tracy area consist of reworked sedimentary material that was derived from <br /> the older rocks of the Coast Ranges and deposited as alluvial fan, flood basin, deltaic, or <br /> lacustrine and marsh deposits Shallow members of the Great Valley Sequence have been <br /> 1 uplifted west of Tracy and dip to the east, from the Coast Range beneath the San Joaquin <br /> Valley Recharge of the water-bearing formations in the hills west of Tracy provides a sig- <br /> mficant head for semiconfined or confined aquifers within the Valley <br /> Shallow subsurface stratigraphy (to a maximum depth of 18 ft-bgs) was investigated at 17 <br /> boring locations Generally, a dark brown fill was encountered from ground surface to a <br /> idepth of approximately 1 ft-bgs m the vicinity of the former UFT (SB-2, SB-3, SB-8, SB-9, <br /> SB-10, SB-11, and SB-12) Typically, the fill was comprised of silty gravel, silty clay, or <br /> asphalt and gravel At Location SB-1/MW-1 (Figure 3), a fill thickness of 12 5 feet was <br /> encountered indicatmg that this was the probable location of the former UFT Fill was not <br /> s National Water Summary, 1984, "Hydrologic Events, Selected Water-Quality Trends, <br /> and Ground-Water Resources," United States Geological Survey, Water-Supply Paper 2275 <br /> 29025 <br /> `REALISTIC SOLUVOMS FOR HAZARDOUS WASTE PROBLEMS" <br />