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1 <br /> In February 1992, groundwater samples were collected from <br /> monitoring wells MW-4, MW-5, and MW-6. Analytical results are <br />' presented in Table 3-1 and in Figure 2-6. <br /> Soils Characterization <br />' The sods underlying the site have been characterized in previous <br /> investigations In general, the Safeway property is underlain by low <br />' permeability silts and clays with discontinuous layers of clayey sand. <br /> At approximately 26 feet below grade, the silts and clays are <br /> underlain by clean to silty sands estimated to have moderate to high <br />' permeability <br /> Figure 2-7 shows the location of the soil cross sections presented in <br />' Figures 2-8 and 2-9, which characterize the soils beneath the Safeway <br /> property <br />' GroundNmtew Characterization <br /> The groundwater underlying the site has also been discussed ;n <br /> previous investigations <br /> Figure 2-10 shows the location of the groundwater cross sections <br /> presented in Figures 2-11 and 2-12, which characterize the <br /> groundwater beneath the Safeway property <br /> Um=jwatar Graghmi and Flow <br /> All of the on-site monitoring wells were surveyed for top-of-casing <br /> elevations to mean sea level by John E Koch, land surveyor, Licensed <br /> Surveyor No 4811, on October 16, 1989 and November 13, 1992 The <br />' USGS benchmark is a 314-inch iron pin monument at the <br /> intersection of Fresno Street and Navy Drive <br /> Based on measured groundwater elevations, the direction of flow <br /> beneath the site on October 3, 1989 was in an east-southeasterly <br /> direction at a very shallow gradient of 0 1% This groundwater flow <br /> direction does not correspond to the northwesterly groundwater flow <br />' direction estimated for September 11, 1987, and the northerly flow <br /> direction estimated for March 28, 1988 The accuracy of these earlier <br /> flow directions is suspect since a professional surveyor was not used <br />' Groundwater elevations were also measured on March 7 and March <br /> 29, 1991 On both occasions, the flow direction was to the south with a <br /> gradient of 0 2% Figure 2-13, a potentiometne contour map <br /> prepared from February 1992 analytical results, is indicative of <br /> groundwater movement over the past two years Groundwater has <br />' consistently been moving in a southerly to southeasterly direction <br />' 2-3 <br /> i <br />