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' 4.0 RESULTS <br /> 4 . 1 Depth to Groundwater <br /> The depth to groundwater has risen approximately 3 feet since <br /> December, to an average depth of 14 feet. Data from both events are <br /> tabulated in Table 1 for comparison. <br /> 4 .2 Groundwater Gradient <br /> The data in Table 1 were used to calculate the groundwater gradient <br /> and determine .the flow direction, which ar•e illustrated in Figure <br /> 3 . Since December, the groundwater flow direction appears -to have <br /> rotated several degrees to the southeast, and the gradient has <br /> increased from 0 . 001 ft/ft to 0. 003 ft/ft. <br /> 4 .3 Laboratory Results <br /> A strong gasoline odor was noticeable in all wells when they were <br /> purged. Relative to the December sampling, concentrations of almost <br /> all analytes increased (Table 2) . As before, concentrations <br /> decrease eastward from KF-3 toward KF-2 . <br /> 5 .0 CONCLUSIONS AND RECOMMENDATIONS <br /> Elevated, and increasing, concentrations of hydrocarbons have been <br /> detected in all three monitoring wells for two successive quarters . <br /> in addition, the gradient has increased, implying that the rate of <br /> groundwater flow has also increased. Based on the available <br /> information, it is likely that groundwater contamination extends <br /> under the Kwikee Foods store and eastward beneath the adjacent <br /> residential property. Hence, additional data points are needed to <br /> the east and northeast of the site in order to adequately map the <br /> a contaminant plume and identify the downgradient extent of <br /> contaminated groundwater. Due to the uncertainty as to the long- <br /> term direction of groundwater flow, three to five additional <br /> borings will' probably be needed to adequately define the plume . A <br /> hydropunch sampling device could be used to sample perhaps three of <br /> these, but at least two additional monitoring wells should be <br /> placed to enable quarterly monitoring through December 1995 . <br /> { San Joaquin County PHS/EHD has requested that monitoring at Kwikee <br /> a <br /> Foods be timed- to coincide with monitoring at the Chevron site. <br /> Second quarter monitoring at the Chevron site is scheduled to occur <br /> in late May. Therefore, Upgradient recommends that the additional <br /> drilling be scheduled for mid-May, so that sampling of the new <br /> wells can take place during the regular mon3tQring event; <br /> eliminating the need for a separate report . <br /> k <br /> 3 <br />