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t <br /> 2.1.3 GROUNDWATER ELEVATION AND FLOW DIRECTION <br /> Measured depths to water have ranged historically from 61.57 to 87.62 feet above mean <br /> sea level or 29.71 feet to 33.65 feet below ground surface. Historical groundwater flow <br /> direction is variable with Neighborhood B being primarily northwest and <br /> Neighborhoods C and D ranging from northeast to northwest. Figures from CRXs <br /> Groundwater Monitoring Report-Third Quarter 2010, October 29, 2010, provide the most <br /> recent groundwater contours and are included in Appendix D. <br /> 2.1.4 GROUNDWATER BENEFICIAL USES <br /> The site is located within the San Joaquin Valley Groundwater Basin, Tracy Subbasin'. <br /> According to the October 2007 RWQCB Central Valley Region Basin Plan, the existing <br /> beneficial uses of groundwater in the Tracy Subbasin are municipal, domestic, <br /> agricultural, industrial process, and industrial. <br /> 2.2 CONSTTFUENT DISTRIBUTIONS <br /> Table 1 summarizes historical soil analytical data from CRA investigations and Table 2 <br /> summarizes the historical groundwater analytical data. Figures 3 through 12 show the <br /> residual total petroleum hydrocarbons as crude oil (TPHc) in soil. Historical soil <br /> analytical data and figures from previous consultant investigation and remediation <br /> activities are included in Appendix E. <br /> 2.2.1 DISTRIBUTION IN SOIL <br /> The TPHc concentrations in all final excavation and well boring samples have been <br /> below the remedial excavation TPHc cleanup level of 5,000 milligrams per kilogram <br /> (mg/kg) with the exception of three soil samples (SAIC, Remedial Action Report, March <br /> 2007). The TPHc concentration was 5,100 mg/kg at EX17-18-B59 at 23 fbg in <br /> Neighborhoods C and D (Appendix E, Table 2, Final Excavation Confirmation Samples <br /> 1 California Department of Water Resources,2006,California's Groundwater bulletin 118 Update 2003, <br /> San Joaquin Valley Groundwater Basin,Tracy Subbasin,updated January 20. <br /> M271(») 2 CONESTOGA-ROVERS&ASSOCIATES <br />