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f� 10 February 2003 AGE-NC Project No 95-0144 ' Page 3 of 4 ' 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) Dunng the December 2002 monitoring event the average ground water elevation at the site was 8 78 feet below mean seal level(MSL),a decrease of 0 62 feet since the September 2002 monitoring event The average depth to water at the site was ' approximately 18 4 feet bsg The approximate hydraulic,gradient for the December 2002 monitoring event was inferred to be 0 003 fit/ft with a flow direction toward the north-northeast (Figure 3) Ground water was within the screened intervals of shallow-screened wells MW-11, MW-12;MW- 13,MW-19A,MW-20A and MW-21A,but was between 0 51 feet and 3 54 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-19B, MW-20B and MW-2113, screened in the Lower Water Zone, were between 1 55 feet and 1 93 feet lower than in the wells ' screened in the Upper Water Zone The approximate hydraulic gradient in the deeper-screened ground water monitoring wells for the December 2007 monitoring event was Inferred to be 0 04 ft/ft lie with a flow direction toward the west-northwest (Figure 3) 3 2 , ANALYTICAL RESULTS OF WA"I FR SAMPLES During the December 2002 monitoring event, TPH-g was detected in the ground water sample ' collected from monitoring well MW-5 at a concentration of 980 micrograms per liter (ugd) Toluene, ethylbenzene and xylenes were detected in the same sample at concentrations of 7 3 ug!1, 71 µgll and 110 µg/l, respectively Target anaiytes were not detected above laboratory reporting limits in the samples collected from wells MW-2 and MW-4 Analytical'results for the fourth quarter 2002 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 0212022-001 through 0212022-003) and chain-of-custody forms are included in Appendix B 1 - " 4 0. SUMMARY/CONCLUSIONS Based upon data collected during the ground water monitoring event, AGE concludes • The average ground water elevation at the site was 8 78 feet below MSL, the lowest measured elevation since November 1997 Ground water remained above the screened . interval in five of the shallow-scieened-wells. sampled during the fourth quarter of 2002 Advanced GeoEnvironmental,Iric � 1