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27 January 2006 <br /> . AGE-NC Project No 98-0500 <br /> Page 6 of 10 <br /> 33 QUARTERLY GROUND WATER 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 /> 3 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 /> from which the ground water samples were collected on the assumption that the elevation will reflect <br /> hydrostatic conditions within the sampled HUs <br /> HU1 - Water table 60 feet <br /> During the December 2005 sampling event,the depth to ground water in shallow monitoring wells <br /> MW-1 through MW-17 ranged from 48 49 feet to 49 96 feet below the tops of the well casings <br /> . (btoc) The ground water elevations were calculated between 31 89 feet (MW-1) and 32 75 feet <br /> (MW-16) below mean sea level (MSL) <br /> Ground water flow direction was northwest and less to the north, flowing radially outward from a <br /> mound centered at the former UST dispenser area towards wells MW-7, MW-8, and MW-9, and <br /> flowing north from the southern portion of site (MW-6) Ground water gradients ranged from <br /> 0 04 foot/foot (ft/ft) under the building (MW-7 through MW-9) to approximately 0 002 at well <br /> MW-5 from the UST release area, and at a gradient of 0 005 ft/ft at well MW-6 south of the former <br /> UST area The ground water elevation map is depicted on Figure 3 <br /> HU3/HU4 - Water table 100 feet <br /> Depths to ground water for the HU3/4 wells (MW-22 through MW-29, MW-38, MW-40, MW-43, <br /> MW-45, and MW-47), screened from 90 feet to 105 feet bsg, ranged from 48 55 feet to 49 88 feet <br /> btoc Ground water elevations were calculated to be between 32 16 feet (MW-23) and 32 56 feet <br /> (MW-29) below MSL <br /> Ground water flow direction was generally toward the southeast under gradients between 0 004 ft/ft <br /> and 0 001 ft/ft, and from the former UST dispenser area toward wells MW-25 and MW-26, <br /> representing a depression in the lower water zone The ground water elevation map is depicted on <br /> Figure 4 <br /> • <br /> Advanced GeoEnvironmental,Inc <br />