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. 30 October 2004 AGE-NC Project No 96-0232 Page 8 of 14 34 FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected on 13 September 2004, the contaminant Impact to ground water was quantified by laboratory analysis of water samples collected on 13 and 14 September 2004 3 4 1 Ground Water Elevation and Gradient The depths to ground water were measured at between 14 67 feet (MW-17118) and 18 41 feet (MW-9C)below the tops of the well casings on 13 September 2004, ground water elevations were calculated to be between 3 73 feet(MW-13D)and 4 76 feet(MW-10E)below mean sea level(MSL) 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 13 September 2004 is 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 and Second Zones, Rocky's Upper Zone, Secondary Zone and Primary Zone However,moderately steep downward gradients were observed from well MW-10 between the First Zone and the Second Zone and from well MW-11 between the Secondary Aquifer Zone and Primary Aquifer Zone (Figure 3) The 13 September 2004 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(15 to 35 feet bsg) at the Flag City Chevron inferred net ground water flow towards the east at hydraulic gradients of 0 001 ft/ft or less The ground water gradient at the Three B's Truck Plaza inferred net ground water flow towards the east-southeast at hydraulic gradients of 0 001 ft/ft or less (Figure 4) Advanced GeoEnvironmental,Inc