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' 5.2 Ground Water Gradient A ground water gradient map was produced from the data obtained from the March 30, 1998 sampling event (Figure 2). The elevations used in the calculation are summarized in Table 5. The ground water flow direction was toward the northwest during this ' sampling event. This gradient and flow direction is consistent with previous monitoring events. ' TABLE 4 Monitoring Well Water Elevations - March 30, 1998 Well Well Collar Depth to Water Ground Water Number Elevation (feet) Elevation (feet) ' (feet) MW-1 57.70' 9.90' 47.80' MW-2 58.82' 10.57' 48.25' MW-3 58.22' 10.02' 48.20' MW-4 57.46' 9.72' 47.74' MW-5 57.86' 10.35' 47.51' MW-6 57.27' 9.84' 47.41' ' MW-7 56.15' 8.19' 47.96' MW-9 56.60' 9.03' 47.57' 5.3 Discussion of Analytical Results Analytical laboratory data indicate a significant change in detected constituent levels in monitoring well MW-1. Individual constituent increases ranged from 33% to over 90% as compared with the previous sampling event results. These changes are believed to be related to the increased rainfall and infiltration experienced during this winter season. These data are similar to the levels found during the March, 1996 sampling event. ' The sample collected from monitoring well MW-6 indicated an increase for all analyzed constituents except toluene, which remained below the analytical detection limit. Benzene, total xylenes and TPH gasoline increased from non detectable levels obtained during the December 1997 sampling event. These data indicate a return to levels found during previous sampling events. ' The remaining wells, MW-5, MW-7 and MW-9, each indicated non detectable levels for all analyzed constituents. These data are consistent with data obtained from previous quarterly sampling events. Monitoring well MW-8 was not sampled because intrusion of ' roots into the well. The bailer blanks were not analyzed for any of the wells. � CA95D$-029 American Geological Services, Inc.I ' ' 13