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south. A detailed discussion of the initial subsurface investigation can be found in RESNA's "Interim Problem Assessment Report, Soil and Groundwater Contamination, " dated June S, 1992 In July 1994, a RESNA field geologist observed the drilling of four additional groundwater monitoring wells (MW4, MW5, MW6, and MW7) at the site to further characterize subsurface conditions. Groundwater samples collected from these additional wells contained no detectable petroleum hydrocarbons A detailed discussion of the Phase 2 Subsurface Investigation can be found in RESNA's "Summary Report, July 1994 Investigation, " dated August 26, 1994 In PHS/EHD correspondence dated March 1995, regulatory approval was given to sample wells MW3 and MW4 and MW5, MW6 and MW7 on an alternating semi-annual basis MW1 and MW2 were to be sampled every quarter, conditions permitting To further define the extent of residual soil contarmnation in the vicinity of the former underground fuel storage tank (UST), Smith Environmental supervised the advancement of four soil borings (SB-1, SB-2, SB-3, and SB-4) on February 29, 1996 to depths of approximately 16 to 26 feet below ground surface (bgs) TPHg and BTEX were detected above method detection ltmrts at low to moderate concentrations in samples collected at depths between 10 and 15 feet bgs in borings SB-1, SB-2, and SB-3 A detailed discussion of this subsurface investigation can be found in Smith Environmental's "Subsurface Investigation Report, " dated April 30, 1996 GROUNDWATER MONITORING AND SAMPLING Smith Technology personnel performed groundwater monitoring and sampling on September 12, 1996 Field work consisted of measuring the depth-to-water in wells MW1, MW2, MW3, MW4, MW5, MW6, and MW7; using an electronic water/product interface probe to determine if free product was present; purging and sampling wells MW1, MW2, MW4, MW6 and MW7; and subjectively evaluating collected water samples for the presence of petroleum hydrocarbon constituents Static groundwater elevations were measured in each monitoring well on September 12, 1996 Groundwater was measured at approximately 13 feet below grade. A groundwater gradient map is presented in Figure 2. It depicts a northwest-southwest groundwater gradient averaging 0.004 ft/ft or approximately 23 feet/mile Fluid level measurements indicated groundwater flow direction beneath the site during the third quarter was not consistent with the last monitoring event The groundwater flow direction during the third quarter 1996 was similar to the flow direction during the third quarter 1995 suggesting a seasonal change in groundwater flow direction. Groundwater monitoring data are summarized in Table 1 943U QUAATLYI3QK 19%DOC 2 Flinn