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24 August 2005 <br /> AGE-NC Project No. 97-0301 <br /> Page 3 of 6 <br /> 3.0. FINDINGS <br /> Ground water elevation,flow direction,and gradient were determined from field data collected on 13 <br /> June 2005. The contaminant impact to ground water was quantified by the ground water samples <br /> ' collected on 13 June 2005. <br /> 3.1. GROUND WATER ELEVATION AND GRADIENT <br /> The depth to ground water measurements at wells MW-1 through MW-12 varied between 30.37 feet <br /> (MW-9A) and 3 2.0 5 feet (MW-I OD)'below the tops of the well casings; ground water elevations <br /> were calculated to be between 18.21 feet(MW-8A)and 19.40 feet(MW-11 D)below mean sea level <br /> ' (MSL). The average ground water elevation at the site on 13 June 2005 was 18.82 feet below MSL. <br /> Generally,ground water elevation at the site increased an average 0.42 feet between the March 2005 <br /> and the June 2005 ground water monitoring events. <br /> ' Ground water elevation data collected on 13 June 2005 from wells MW-8 A-C MW-9.(A-D),and <br /> MW-12(A-D)is depicted on'cross section D-D'(Figure 3).By determining the difference between <br /> ' ground water elevations(dh)and dividing by the difference of the screen interval midpoints(dl),the <br /> vertical gradient between adjacent screen intervals was calculated. Generally, moderately steep to <br /> steep downward vertical gradients were observed between the Second, Third, and Fourth Water <br /> ' Zones;while near neutral to upward vertical gradients were observed between the First Water Zone <br /> and the Second Water Zone in the southern portion of the site (Figure 3). <br /> ' The ground water elevations at wells MW-1 through MW-12 were calculated by subtracting the <br /> measured depth to ground water from the surveyed casing elevation. The June 2005 ground water <br /> elevation data collected from wells MW-1 through MW-7 were plotted for the First Water Zone <br /> (Figure 4) as defined in AGE's CPT Site Investigation - Third Quarter 2001 (dated 25 October <br /> 2001). Generally, the net ground water flow direction was toward the east-southeast at an <br /> ' approximate hydraulic gradient of 0.006 foot/foot (ft/ft). The local ground water flow direction at <br /> the former UST location'was generally northeast, in accordance with the former flow directions. <br /> . 1 <br /> 1 <br /> Advanced GeoEnvironmental,Inc. <br /> i <br />