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i 1 ' 10 August 2005 • AGE-NC Project No. 97-0301 Page 3 of 6 • Benzene,toluene,ethylbenzene,and xylenes(BTEX),methyl tertiary-butyl ether(MTBE), ' 1,2-Dichloroethane(1,2-DCA),ethylene dibromide(EBD),di-isopropyl ether(DIPE),ethyl tert-butyl ether(ETBE),tert-amyl methyl ether(TAME),and tertiary butanol(TBA)by EPA ' Method 8260B. • I ' 3.0. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data collected ' on 15 March 2005. The contaminant impact to ground water was quantified by the ground water samples collected on 15 March 2005. VIP 3_0� 3.1. GROUND WATER ELEVATION AND GRADIENT MW I8 The depth to ground water mea urem satAbe ells MW- through MW-12 varied between 30.82 feet (MW-9A)and 32. feet(MW2WO Pops ofthe well casings;ground water elevations were ' calculated to be between 18.47 feet (MW-lOA) and 19.91 feet (MW-11D) below mean sea level (MSL).The average ground water elevatiori at the site on 15 March 2005 was 19.24 feet below MSL. Generally, ground water elevation at the site increased an average 3.79 feet between the December ' 2004 and the March 2005ound water monitoring events. aG S �' iig Ground water elevation data collected on 15 March 2005 from wells NW-- (A-C), MW-9 (A-D), I and MW-12 (A-D) is depicted on cross section D-D' (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, moderately ' steep to steep downward vertical gradients were observed between the Second, Third, and Fourth Water Zones;while near neutral vertical gradients were observed between the First Water Zone and the Second Water Zone in the southern portion of the site (Figure 3). 1 - through MW-12 were calculated b subtracting the The ground water elevations at wells MW 2 t g y g measured depth to ground water from the surveyed casing elevation.The March 2005 ground water elevation data collected from wells MW-2 through MW-7 were plotted for the First Water Zone (Figure 4) as defined in AGE's CPT Site Investigation - Third Quarter 2001 (dated 25 October 2001). Generally, the net ground water flow direction was•toward the northeast at an approximate ' hydraulic gradient of 0.003 foot/foot(ft/ft). Advanced GeeEnvironmental,Inc. i � 1 I