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� � 1 ' r �I ,1 a7 i ' I . 06 August 2003 AGE-NC Project No 95-0144 - Page 3 of 5 ' 3.0 FINDINGS Ground water elevation and flow direction were inferred from field data, hydrocarbon-impact to ground water was quantified from laboratory analysis of the ground water samples i 3 1 GROUND WATER ELEVATION AND GRADIENT The elevation of ground water in each well was calculated by subtracting the depth to water from the ' surveyed casing elevation (Table 1) During the May 2003 monitoring event the average ground water elevation at the site was 8 1 feet below mean seal level(MSL), a increase of 0 6 feet since the February 2003 monitoring event The average depth to water at the site was approximately 17 7 feet bsg The approximate hydraulic gradient for the May 2003 monitoring event was inferred to be 0 003 Rift with a flow direction toward the north-northeast (Figure 3) 1 Ground water was within the screened Intervals of shallow-screened wells MW-11, MW-12, MW-13,MW-18,MW-19A,MW-20A and MW-21A,butwas between 1 15 feet and 4 14 feet above the screened interval in the shallow-screened wells MW-1, MW-2, MW-4, MW-5 and MW-8 Ground water elevations in the deep-screened nested wells MW-1913, MW-20B and MW-2113, ' screened in the Lower Water Zone, were between 1 40 feet and 1 70 feet lower than in the wells screened in the Upper`Water Zone The approximate hydraulic gradient in the deeper-screened groundwater monitoring wells for the May 2003 monitoring event was Inferred to be 0 003 Rift with r a flow direction toward the west-northwest (Figure 3) - , , 32 ANALYTICAL RESULTS OF WATER SAMPLES During the May 2003 monitoring event,TPH-g was detected in ground water samples collected from ' monitoring wells MW-21 A and MW-21 B at concentrations of 2,900 micrograms per liter(µg/l)and 830 µg/1, respectively TPH-d was detected in samples collected from wells MW-19A, MW20A, MW-21 A and MW-21B at concentrations of 90 µg11, 86 µg/1,3,900 µg/1 and 430 µg/1,respectively ' The fuel oxygenate MTBE was detected in 14 of the 15 monitoring wells at concentrations ranging from 0 55 µg/1 (MW-20B) to 4 9 µg/l (MW-4) Other target analytes were not detected above ' laboratory reporting limits in the samples collected from the monitoring well network Analytical results for the second quarter 2003 monitoring event are summarized on Tables 2 and 3 ' Analytical results of recent and historical ground water samples are summarized on Tables 4 and 5 The laboratory report (MAI Lab IDs 0305148-001 through 03005148-015) and chain-of-custody forms are included in Appendix B Advanced GeoEnvironmentai,Inc w i