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30 January 2004 AGE-NC Project No 96-0232 Page 9of15 34 FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected on 08 December 2003, the contaminant impact to ground water was quantified by laboratory analysis of water samples collected on 08, 09 and 10 December 2003 3 4 1 Ground Water Elevation and Gradient The depths to ground water were measured at between 12 07 feet(MW-18)and 16 06 feet(MW-9C) below the tops of the well casings on 08 December 2003, ground water elevations were calculated to be between 3 86 feet (MW-13A) and 4 55 feet (MW-8C) below mean sea level (MSL) Ground water elevation at the site generally Increased an average 108 feet between the September and the December 2003 ground water monitoring events Ground water elevation data collected from Flag City Chevron wells MW-9 (A-C),MW-11 (A-D), MW-13 (A-D), MW-16, MW-17, MW-18 and Three B's Truck Plaza wells MW-6, MW-9 (A-E) and MW-10 (A-F) on 08 December 2003 was depicted on cross section GC' (Figure 3), by • determining the difference between ground water elevations (dh) and dividing by the difference of the screen interval midpoints (dl), the vertical gradient between adjacent screen Intervals was calculated Generally,nearly flat,very slight upward and downward vertical gradients were observed between the First Zone, Second Zone, Rocky's Upper Zone, Secondary Zone and Primary Zone screen intervals of all the above wells (Figure 3), a moderate downward vertical gradient was observed at well MW-11 between Second Zone and Rocky's Upper Zone The 08 December 2003 ground water elevation data collected from the Flag City Chevron site and the adjacent Three B's Truck Plaza site were plotted for the informal First Zone, Second Zone, Secondary Aquifer Zone and Primary Aquifer Zone hydrogeologic units as defined in AGE's Final Remediation Plan, and are depicted in Figures 4, 5, 6 and 7, respectively 3 4 1 1 First Zone Aquifer Ground water elevation data collected in the First Zone Aquifer(10 to 35 feet bsg)at the Flag City Chevron was inferred to have a radially inward flow direction towards a ground water depression in the area ofFlag City Chevron wells MW-1,MW-2 and MW-4(Figure 4)at ground water gradients of 0 004 ft/ft or less The ground water gradient at the Three B's Truck Plaza was inferred to be towards the east-northeast at hydraulic gradients of 0 002 ft/ft or less Advanced GcoEnvironmentat,Inc