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f 1 i I II II I Project No 58080-06-02 May 5, 1995 Very stiff to hard, olive to greenish gray, silty clay and very clayey sand was encountered beneath the sand layer, extending to depths on the order of 47 to 51 feet bgs Interbedded sand and clay ' strata, in thicknesses ranging from 1 to 3 feet, were encountered below the silty clay and clayey sand layer to 55 feet bgs Aquifer sediments were encountered at a depth of approximately 60 feet ' bgs and consist of dense or moderately dense fine to medium grained sand to the maximum boring depth of 71 5 feet bgs Generalized north-south and east-west trending geological cross sections are presented as Figures 31 land 4, respectively Copies of boring logs and well completion diagrams are included in Appendix A ' 3 3 Site Hydrogeology The depths to groundwater across the site measured on November 30, 1994 ranged from -9 81 to - 9 47 feet below Mean Sea Level (MSL), or approximately 55 feet bgs The direction of groundwater flow is generally to the south-southwest with a gradient ranging from approximately 0 002 to 0 005 feet/foot A cumulative summary of groundwater elevation measurements is ' presented on Table 11 Groundwater elevation contours and the groundwater gradient direction on November 30, 1994 are depicted on the Groundwater Elevation Map, Figure 5 34 Soil Sample Analytical Results I Soil samples collected from borings GB-6 through GB-11, MW-4 and MW-5 were tested for the presence of TPHg, TPHd, BTEX and MTBE The cumulative results of previous soil analyses performed between March 1991 and April 1994 are summarized in Table III A summary of soil ' sample analyses performed since July 1994, including the soil sample analytical results for this phase of investigation are presented in Table IV Copies of laboratory reports and sham-of custody records are included in Appendix C I I -17- fi 1 i I „ li