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groundwater monitoring was begun at this site in August 1993 The water level data were used to develop the groundwater elevation contour map (Figure 2) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site flowed towards the southeast with a slight mounding effect noted in the vicinity of well MW-2 The average hydraulic gradient on January 27, 1997 was calculated to be 0 005 ft/ft or approximately 26 ft/mile A summary of groundwater monitoring data is presented in Table 1 CONCLUSIONS Petroleum hydrocarbon constituents remained detectable in the groundwater samples collected from well MW-3 Concentrations of petroleum hydrocarbon constituents increased approximately one order of magnitude in well MW-3 since the last monitoring episode in January 1997 In well MW-6, concentrations of petroleum hydrocarbon constituents were not detected for the first time since monitoring began The current groundwater elevation, 19 15 feet bgs, is above the top of the screen, approximately 20 feet bgs, in the onsite monitoring wells Because of the extremely high groundwater elevation, the petroleum hydrocarbon concentrations in groundwater at this time are representative of the screen interval and not the groundwater table The direction of groundwater flow and the magnitude of hydraulic gradient are consistent with the previous quarter Groundwater elevations have increased due to seasonal conditions and record rainfall RECOMMENDATIONS Based on the results of the second quarter 1997 monitoring episode, we recommend the following o Conduct the Third Quarter 1997 groundwater monitoring and sampling of wells MW-1 through MW-6 o Evaluate the need for vapor extraction at the site after the groundwater elevations have dropped below the top of the screen in the onsite wells and an accurate evaluation of petroleum hydrocarbon concentrations in groundwater can be made w 1943731quaA1yl2gr-1997&c 3 • SMTH