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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 April 12, 1996 was calculated to be 0 007 ft/ft or approximately 40 ft/mile A summary of groundwater monitoring data is presented In Table 2 CONCLUSIONS Petroleum hydrocarbon constituents remained non-detectable In the groundwater sample collected from weIIs MW-1, MW-2, MW4 and MW-5 Concentrations of petroleum hydrocarbon constituents generally decreased in the groundwater samples collected from wells MW-3 and MW-6 since the last monitoring episode in January 1996 The extent of groundwater contamination has been fully dehneated in the south and east directions but not in the northeast direction due to concentrations of petroleum hydrocarbons detected in wells on the northeast corner of the property The direction of groundwater flow and the magnitude of hydraulic gradient are consistent with the previous quarter Groundwater elevations have risen due to seasonal conditions RECOMMENDATIONS Based on the results of the second quarter 1996 monitoring episode, we recommend the • following o Continued quarterly monitoring of depth to water In all wells on site o Continued quarterly sampling of weIIs MW-3, MW-4, MW-5 and MW-6 o A reduction in sampling of wells MW-1 and MW-2 to semiannual, during first and third quarters Well MW-1 has never contained detectable concentrations of petroleum hydrocarbons since monitoring began Well MW-2 has not contained detectable concentrations of petroleum hydrocarbons for the last three quarters of sampling w 1943731quan1yl2gr-1996 doc 3 • SM7H