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3� Groundwater Flow Direction/Gradient (mid-depth wells) NA Depth to Groundwater(deep wells) 48 68 to 50 53 feet below to of well casin Groundwater Flow Direction/Gradient (deep wells) East to 012 ft/ft DISCUSSION As discussed in the Site Conceptual Model (SCM), review of the subsurface geology and groundwater well elevation data indicate that although different transmissive (i a sandy) zones have been Identified at various depths at this site, these zones appear to be hydraulically connected and likely form one continuous water-bearing zone Groundwater monitoring wells have been screened at three distinct intervals Shallow screened wells VEW-1, VEW-2, MW-2 through MW-7, and MW-15 were screened at various depth intervals between 40 and 70 feet below ground surface (bgs) Samples collected from these wells currently represent groundwater concentrations at first encountered groundwater Deeper screened wells intended to target sandy, more transmissive zones that may represent preferential pathways for petroleum hydrocarbon migration Mid-depth wells MW-16 and MW-18 are screened in sandy zones between 85 and 90 feet bgs Deep wells MW-8 through MW-11 and MW-17 are screened between 94 and 120 feet bgs, within a laterally continuous sandy unit first encountered at approximately 95 to 105 feet bgs Shallow Wells At the time of the second quarter 2004 monitoring event, groundwater was encountered in the shallow monitoring wells at depths ranging from 47 82 to 49 35 feet bgs Well MW-3 is obstructed Groundwater elevations had increased between 0 11 and 0 28 feet in the shallow wells since the previous monitoring event (February 23, 2004) Groundwater monitoring data were normalized to mean sea level (MSL) and used to prepare a groundwater elevation contour map (Figure 2) The groundwater flow direction on May 24, 2004, was toward the east-northeast at a gradient of 0 001 ft/ft Since 1995, groundwater flow in the shallow wells has consistently been toward the east and southeast In the shallow wells, THPG and benzene were reported in wells VEW-1, and VEW-2 The highest concentrations of TPHG (120,000 µg/L) were reported In both wells VEW-1 and VEW-2, and the highest concentrations of benzene (1,100 µg/L) were also reported in both wells VEW-1 and VE 1 2-DCA , (4 2 µglL) was reported in well MW-2 MTBE, D1PE, ETBE, TAME, TBA, or EDB were not repoed in any of the shallow wells These analytical results are generally consistent with historical data TPHG, benzene, and MTBE concentrations for samples collected and analyzed during the second quarter 2004 are summarized on Figure 3 Mid-Depth Wells At the time of the second quarter 2004 monitoring event, groundwater was encountered in the mid-depth monitoring wells at depths of 48 53 and 49 34 feet bgs Since only two mid-depth monitoring wells have been installed, groundwater flow direction and gradient cannot be calculated at this time Depth-to-water measurements have been summarized on Figure 4 TPHG (450 µg/L), benzene (19 µg/L), TBA (110 µg/L), and 1,2-DCA(210 µg/L)were reported in well Mw_ 18 Petroleum hydrocarbons or fuel additives were not reported in the sample collected from well MW-16 TPHG benzene and MTBE concentrations for samples collected and analyzed during the second quarter 2004 are included on Figure 5 P wache Plastics\Quarterly reportsQ00AApache_2Q04 DOC snegrus