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24 October 2005 <br /> r AGE-NC Project No. 98-0500 <br /> Page 8 of 11 <br /> 4.3. FINDINGS <br /> Ground water elevation and flow direction were inferred from the field data; hydrocarbon-impact <br /> to ground water was quantified by laboratory analysis of the ground water samples. <br /> 4.3.1. Ground Water Elevation and Gradient <br /> The elevation of ground water in each monitoring well was calculated by subtracting the depth to <br /> ground water from the surveyed casing elevation; current and historical ground water elevation <br /> results are provided in Table 3.Each ground water elevation is grouped according to the HU or HUs <br /> that the well samples,on the assumption that the elevation will reflect hydrostatic conditions within <br /> the sampled HUs. <br /> HU1 - Water table 60 feet <br /> During the August 2005 sampling event, the depth to ground water in shallow monitoring wells <br /> ranged between 56.84 feet and 56.69 feet below the top of the casing (btoc). The ground water <br /> elevations were calculated to be between 38.47 feet(MW-1) and 39.21 feet(MW-11)below mean <br /> sea level (MSL). <br /> Ground water flow direction was west from the former UST dispenser area towards wells MW-7/8 <br /> and south from the southern portion of site (MW-6). Ground water gradients ranged from 0.003 <br /> foot/foot (ft/ft) at well MW-1 at the UST release area and at a gradient of 0.01 ft/ft at well MW-6 <br /> south of the former UST area.Additionally,a northern ground water flow direction was modeled at <br /> the western edge of the site at a gradient of 0.005 ft/ft. The ground water elevation map is depicted <br /> in Figure 3. <br /> HU3/HU4 - 100 feet <br /> Depths to ground water for the HU3/4 wells screened from 90 feet to 105 feet bsg,ranged between <br /> 56.96 feet and 54.84 feet btoc. Ground water elevations were calculated to be between 38.02 feet <br /> (MW-24) and 39.63 feet (MW-22) below MSL. Ground water flow direction was west from the <br /> former UST dispenser area towards wells MW-25/26 at a gradient of 0.002 ft/ft The ground water <br /> elevation map is depicted in Figure 4. <br /> HU6 - 150 feet <br /> Depths to groundwater for deep-screened wells(140 feet to 150 feet bsg)ranged between 56.22 feet <br /> and 57.69 feet below the tops of the well casings. Ground water elevations were calculated to be <br /> Advanced GeoEnvironmental,Inc. <br />