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1 h y S <br /> , h � <br /> , F l <br /> 1 � i <br /> 15 January 2005 <br /> AGE-NC Project No 96-0235 J <br />' Page 3 of 5 <br /> F <br /> 1 <br /> 31 GROUNDWATER GRADIENT AND FLOW DIRECTION <br /> Depths to ground water ranged from 19 05 feet to 21 99 feet below the tops of the well casings, <br /> ground water was within the,screened intervals of the shallow wdlls;but was approximately 9 feet <br /> above the screened Interval of intermediate wells MW-3 and EW-2 and between 19 and 45 feet <br /> above the screened intervals of the deep wells <br /> h <br /> The'elevation of ground water in each well was calculated by subtracting the depth to ground water <br /> from the surveyed casing elevations (Table 1) Ground water elevations'at the site ranged from <br />' 13 93 feet(MW-15A)to 15 48 feet(MW-2)below mean sea level(MSL) The average ground water <br /> elevation at the site was approximately 14 32 feet below MSL The average ground water elevation <br /> in the wells decreased by approximately 0 54 feet since the August 2004 ground water monitoring <br />' event <br /> Figure 3 and Figure 4 illustrate the ground water potentiometric surface based on the shallow- and <br />' deep-screened data sets Near the former UST cluster, ground water flow direction at the shallow- <br /> screened data was inferred to be towards the east at a gradient of 0 001 ft/ft, the deep-screened data <br />'. delineated a ground water flow direction toward the south at a gradient of 0 005 f1/ft Near the former <br /> UST No 3 excavation ground water flow direction at the shallow-screened data was inferred to be <br /> towards the east at a gradient of 0 003 ft/ft, ground water flow direction at the deep-screened level <br /> was inferred to be toward the south-southwest at a gradient of 0 014ft/ft <br /> 1 <br />' 32 ANALYTICAL RESULTS OF WATER SAMPLES <br /> TPH-g was detected in the samples collected from MW-1,MW-2,MW-9,MW-11B,MW-14B and <br />' EW-2 at concentrations ranging from 200 micrograms per liter (µg/l) in samples MW-9 and <br /> MW-14B to 12,000 µg/1 in sample MW-2 TPH-d was detected in samples collected from MW-1 r� <br /> and MW-2 at concentrations of 4,800 µg/1 and 10,000 µg11, respectively i <br /> Various BTEX compounds were detected in samples MW-1, MW-2 and EW-2 at maximum <br /> concentrations of 2,000 µg/1 benzene (MW-1), 270 µg/1 toluene (MW-2), 840 µg/1°ethylbenzene <br /> I (MW-2) and 1,3645µg/1 xylenes (MW-2) <br /> MTBE was detected in the water samples collected from MW-9, MW-10, MW-11B, MW-'1 2B, <br /> MW-13B and MW-14B at concentrations ranging from 20 µg/1 (MW-12B) to 210 µg/1 (MW-9) <br /> Water samples analyzed from MW-11B, MW-13B and MW-14B contained detectable <br /> concentrations of 1,2-DCA ranging from 2 2 µg/1 (MW-1 IB) to 26 µg/l (MW-14B) D1PE, ETBE, <br /> TAME,TBA,EDB,methanol and ethanol were not detected above laboratory reporting limits in any <br /> of the water samples collected during the November 2004 monitoring event <br /> F <br /> Advanced GeoEnvironmental,Inc <br />