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r r I I 31 August 1999 ' AGE-NC Project No 97-0290 Page 4 of 6 ' The storativity was calculated to range from 5 03 x 10-3 to 6 55 x 10-6 (unitless) I A radius of influence from 13 to 24 feet was calculated using the 1-minute data, a radius of influence of 16 to 31 feet was calculated using the 10-minute data, a radius of influence of 20 to 40 feet was calculated using the 100-minute data Measurable drawdown was observed in wells MW 1 and MW4, I located approximately 60 and 75 feet, respectively, from V W 1 C Wells S W 1 and S W2 are screened at a different interval than the extraction well, V W 1 C and may account for some variations in the observed induced drawdown I ' 3 2 GROUND WATER GRADIENT AND FLOW DIRECTION The depths to ground water ranged from 42 59 feet to 44 55 feet below the tops of the well casings on 21 July 1999 The elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed casing elevations Ground water elevations ranged from 4 71 to 4 28 feet above mean sea level (MSL) Ground water elevation decreased an average of 0 80 feet Ibetween 30 April and 21 July 1999 Ground water data is summarized on Table 1 Ground water elevation contours based upon the data for the July 1999 monitoring event is Iillustrated on Figure 3 The ground water flow direction was southerly with a gradient of 0 0016 3 3 ANALYTICAL RESULTS OF WATER SAMPLES I TPH-g was detected in water samples collected from MW1, MW2 and MW4 at concentrations of 450 parts per billion (ppb, reported as micrograms per liter), 49,000 ppb and 11,000 ppb, respectively TPH-d was detected in samples collected from MW 1, MW2, MW4, MW7 and MW8 I at concentrations of 290 ppb, 4,400 ppb, 3,000 ppb, 64 ppb and 54 ppb, respectively BTEX compounds were detected at concentrations as high as 6,600 ppb, 1,800 ppb, 250 ppb and 4,000 ppb, respectively(MW2) Petroleum hydrocarbons were not detected in the samples collected from MW3 ' and MW5 Only benzene was detected in MW-6 at a concentration of 0 79 ppb, only TPH-d was detected in MW7 and MW8 IDIPS was detected in the sample collected from MW6 at a concentration of 0 86 ppb Tertiary butanol was detected in the samples from MW1 and MW6 at concentrations of 15 ppb and 5 0 ppb, respectively Oxygenated compounds were not detected in remaining samples collected from the site during the July 1999 sampling event Analytical results of all water samples collected at the site are • summarized on Tables 2 and 3 The laboratory report(AAL Order No 99072709), chain-of-custody Iforms and QA/QC are included in Appendix D IAdvanced GeoEmironmental,Inc