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x� �� , , a �� ':=;• fir. . `� �>� � � � - � ��, �— southorn limits of the former tank field/backfilled excavation. The contaminated soils do not extend to 36 feet in depth, being primarily between depths of 16 and 31 feet. Soiia sampled in the outlying monitoring wells MWI, MW2, M43, MW5, and MNG contain concentrations significantly less than l mg/kg, in KW7 and M6 less than 3 mg/kg. 3.7. HYDROG£OLOGIC RESULTS Table 5 is a summary of the depths to ground water and the calculated elevations of the top of ground water. The elevations of the top of ground water are also summarized on Figures 13 and 14 . The static water table is at an elevation of 22 to 23 feet r below mean sea level, 35,38 to 36.47 feet below the ground surface and the tops of casing. The static water table has risen from the depths at which it was first encountered, suggesting an aquifer that is confined by both an upper and lower confining layers/bedu. The groundwater apparently flows to the northeast down a hydraulic gradient of 0.003. The geology beneath former Chevron SS 9^1916 consists of three general stratigraphic units of unconsolidated sediments (Figures 15, 16, and 17) . The upper layer is a section of silty and sandy clays and silts that varies in thickness. Groundwater appears to a be contained in a layer of clean and silty sands below the shallower clays; this sand occurs at depths below the ground surface of 14 to 43 feet-. This sand is imtediately underlain by i an olive gray clay that is very tough and plastic, and apparently 5 r relatively less permeable than either of the overlying layers. 3.3 CONCLUSIONS The contaminated soils appear to be limited to an area ira.:.diately within the extant of the former tank field :he water — - -- �r�'. contaminated by this source of petroleum hydrocarbons .is concentrated around MW4 and MW3; concentrations diminish in all k