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SECTION 4 <br /> �J <br /> FINDINGS <br /> Findings from investigations performed at the former tank site #2 <br /> have resulted in the characterization of soil types, as well as the <br /> groundwater depth and gradient. Laboratory analyses have resulted <br /> in the characterization of the nature of the release, including its <br /> lateral and vertical extent These findings are discussed below <br /> Soil Characterization <br /> The information obtained during the installation of monitoring wells <br /> and soil borings indicates that the site is underlain by clays, silts and <br /> sands Figure 4-1 represents a cross-section of former tank site #2, <br /> the location of the cross-section is provided in Figure 1-2 Fill was <br /> encountered in varying thicknesses in all of the bonngs It occurred <br /> in the first 3 feet of MW-1A and MW-3A, and in the first 7 feet of MW- <br /> 2A and MW-4A In general, semiconsolidated silty and clayey soils <br /> extend from beneath the fill to a depth of approximately 10 to 20 feet <br /> Below the silts and clays, unconsolidated fine- to coarse-grained <br /> sands are present. These sands contain localized layers of silt and <br /> gravel. No elevated readings were obtained from the headspace <br /> measurements <br /> Groundwater Levels <br /> Water level data are provided in Table 4-1 Tidal data are provided in <br /> Table 4-2 As previously discussed, groundwater at the site is <br /> confined and hes at a depth of approximately 5 feet below the ground <br /> surface The data obtained during this investigation indicates that <br /> general groundwater flow gradient is towards the southeast. Figure <br /> 4-2 depicts the groundwater flow direction on April 3, 1992. However, <br /> flow direction and gradient may vary because of tidal water-level <br /> fluctuations in the nearby Deep Water Channel. The groundwater <br /> data were obtained during a period of relatively high tides <br /> As discussed in Section 3, it appears that the groundwater at MW-2A <br /> PP <br /> is perched and is not in communication with the groundwater that <br /> was encountered in the other monitoring wells. This inference is <br /> f supported by the fact that the groundwater elevation is higher at this <br /> point than in the surrounding wells <br /> 4-1 <br /> L <br />