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iI <br /> Water consumption at Plant 33 is highest during the peach canning season when all <br /> ( three Del Monte wells are operated. The peach canning season began in July and <br /> ended September 19 in 1991. Water levels in the shallow wells nearest the plant rose <br /> almost 2 feet after canning season ended (Table 3-2). <br /> Shallow Groundwater Movement <br /> Horizontal Flow <br /> I <br /> Figures 3-4, 3-5, and 3-6 show interpretations of the shallow groundwater surface <br /> i beneath the property on September 9, 1991, September 23, 1991, and October 8, 1991, <br /> j respectively. On September 9, 1991, during the peach canning season, groundwater was <br /> observed to flow northwesterly toward the - Del Monte production wells at an <br /> ( approximate gradient of 0.0013;. a cone of depression appeared to surround the Del . <br /> . Monte production wells. On September 23, 1991, 4 days after the end of the peach <br /> canning season, groundwater was observed to flow northwesteay at an approximate <br /> gradient of 0.001 near the former tank pit and 0.0005 near the Del Monte production <br /> I wells. On October 8, 1991, nearly 3 weeks after the end of the peach canning season, <br /> groundwater was observed to flow northwesterly at a gradient between 0.0005 and <br /> 0.001. <br /> f <br /> Vertical Flow <br /> l <br /> Monitoring Well MW-DIS-7D was installed 15 feet from Monitoring Well MW-DIS-7S <br /> in order to. determine the vertical groundwater gradient. Water levels indicate <br /> downward gradients of 0.006 and 0.02 on September 23, 1991, and October 8, 1991, <br /> respectively. These gradients indicate a potential for significant downward flow. <br /> Soil Investigation Results <br /> Soil-Gas Survey <br /> The results of the soil gas sample analyses are presented in Table 3-3.. The results <br /> indicate that little to no hydrocarbon vapor exists in the upper 13 feet of the subsurface <br /> surrounding the former gasoline tanks and gasoline dispensing islands. <br /> Soil Sample Analytical Results <br /> All soil samples collected were analyzed for TPH-Gas, BTEX, and lead. The analytical <br /> results are summarized in Appendix F. Of the seven soil borings drilled in the <br /> immediate vicinity of the former tank pit (SB-DIS-1, 2, 3, 4, 5, 6, and 7), four borings, <br /> SB-DIS-1., 3, 6, and 7, had detectable levels of TPH-Gas. The levels of TPH-Gas in <br /> Borings SB-DIS-1 and 7 were, however, only slightly above the detection limit of <br /> 1 mg/kg. Higher concentration of benzene and TPH-Gas were found in boring <br /> SB-DIS-3 at depths between 60 feet and 75 feet bgs. <br /> I <br /> SF0316041RP1006.51 3-7 <br />