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21 February 2000 <br /> AGE-NC Project No. 95-0185 <br /> ' Page 4 of 8 <br /> 2.8. DISPOSAL OF PURGED GROUND WATER <br /> On 05 August 1999, approximately 2,000 gallons of purged ground water, collected during a <br /> ' feasibility test at the site,were collected by Delta Oilfield Services of Woodland, California for final <br /> disposal at a licenced treatment facility. A copy of the generators manifest are included <br /> in Appendix C. <br /> 1 <br /> 4.0. FINDINGS <br /> ' Ground water was inferred to have a northerly flow direction and was found to be locally impacted <br /> acted <br /> by petroleum hydrocarbons and oxygenated fuel additives.Petroleum hydrocarbon-impacted soil was <br /> detected at depths of fifteen and twenty-five feet bsg. <br /> 4.1. GROUND WATER GRADIENT AND FLOW DIRECTION <br /> The relative elevation of ground water in each well was calculated by subtracting the ground water <br /> I� depth from the surveyed casing elevation. Monitoring well casing elevations were surveyed relative <br /> to a MW-4, which was assigned an arbitrary elevation of 60 feet above sea level. <br /> ' During the June 1999 sampling event, the depth to ground water at the site ranged from 18.14 to <br /> 18.75 feet bsg. The relative ground water elevation at the site ranged from 41.70 to 41.78 feet. The <br /> ' ground water flow direction measured from the data collected during the sampling event was toward <br /> the southwest, at a hydraulic gradient of 0.0006. The relative ground water elevations at the site are <br /> contoured on Figure 3. <br /> Ground water at the site has a very low gradient. At such a low gradient, normal measurement error <br /> can equal or even surpass the differences between wells, and can greatly influence the inferred <br /> ground water flow direction determination. The regional ground water flow direction is generally <br /> southwest. <br /> 1 <br /> 4.2. . HYDROCARBON-IMPACTED GROUND WATER <br /> Four ground water wells on the site were sampled. Each sample was analyzed for TPH-g;TPH-d and <br />' BTEX, with analysis for MTBE, and each sample was analyzed for the suite of five fuel additives. <br /> Additionally, five grab water samples were analyzed; along with one ground water sample for <br /> . microbial activity. <br /> Advanced GeoEnvironmental,Inc. <br />