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1 <br /> I L31 January <br /> 2003 <br /> s AGE-NC Project No 96-0232 <br />' <br /> Page 9of17 <br /> 1 <br /> s � <br /> • Methanol,ethanol, 1,2-DCA,EDB,MTBE,TAME,DIPE,ETBE and TBA by EPA Method ` <br />' 8260 Modified <br /> 3 4 FINDINGS <br />' Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 04 December 2002, the contaminant Impact to ground water was quantified by laboratory analysis <br /> of water samples collected on 05'and 06 December 2002 <br /> I ' <br /> 3 4 1 Ground Water Elevation and Gradient <br /> r <br /> The depths to ground waterwere measured at between 12 09 feet(MW-18)and 16 10 feet(MW-9C) <br /> I below the tops of the well casings on 04 December 2002, ground water elevations were calculated <br /> to be between 3 84 feet (MW-13A) and 4 58 feet (MW-9C) below mean sea level (MSL) Ground <br /> water elevation at the site generally increased an average 4 41 feet between the September 2002 and <br /> the December 2002 ground water monitoring events <br /> Ground water elevation data collected from multi-level wells MW-9 (A, B and C), MW-11 (A, B, <br /> C and D) and MW-13 (A, B, C and D) on 04 December 2002 was depicted on cross section C-C' <br /> (Figure 3),the vertical gradient between adjacent screen Intervals is depicted on cross section C-C' <br /> The vertical gradient between adjacent screen intervals was calculated by determining the difference <br /> I n between ground water elevations(dh)and dividing by the difference of the screen interval midpoints <br /> (dl) Generally, very slight downward vertical gradients were observed between the First Zone, <br /> Second Zone, Rocky's Upper Zone, Secondary Zone and Primary Zone screen intervals of MW-9, <br /> MW-11 and MW-13, however, a slight increase in upward vertical gradient was measured between <br /> the screen intervals at wells MW-9AB and MW-11CD <br /> The 04 December 2002 ground water elevation data collected from the Flag City Chevron site and <br /> the adjacent Three B's Truck Plaza site were plotted for the informal,First Zone, Second Zone, <br /> Secondary Aquifer Zone and Primary Aquifer Zone hydrogeologic flow units as defined in AGE's <br /> Final Remediation Plan, and are depicted in Figures 4, 5 and 6 f <br /> 3 4 1 1 First Zone Aquifer <br /> Ground water elevation data collected in the First Zone Aquifer(10 to 35 feet bsg) at the Flag City <br /> I Chevron site inferred a southeast to east ground water flow direction that from the area of the Flag <br /> MCity Chevron well MW-13A, located at the Three B's Truck Plaza, towards a ground water <br /> Advanced GeoE nviron mental,Inc <br /> , <br />