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r • 14 May 2003 AGE-NC Project No 01-0865 Page 4of5 I2 2 5 Extracted Ground Water Disposal On 06 August 2001, the ground water extracted during the pumping test was pumped from the { aboveground storage poly tank into a vacuum truck (supplied by American Valley Waste Oil), approximately 2,650 gallons ofpurged water was transported off-site under a non-,hazardous waste manifest to Seaport Petroleum, a waste treatment facility located in Redwood City, California Documentation and uniform hazardous waste manifests for disposal of the pump test extracted water is contained in Appendix F ' r 3.4. ' SUMMARY AND CONCLUSIONS < The implications from the aquifer ground water pumping tests are • During the aquifer pumping rate test, maximum ground water draw-down of 7 98 feet was observed in extraction well EW-2 following approximately 465 minutes of pumping operation, ground water draw-down was observed m each of the observation wells ranging from 1 96 feet(MW-2 located approximately 15 feet west-southwest of EW-2)to 0 05 feet (MW-5 located approximately 84 feet south of EW-2) Draw-down results are presented on Table 2 and in Appendix A, Figure 2 illustrates well locations • Utilizing a semi-logarithmic plot of ground water draw-down vs observation well distance to pumping well(Jacob straight-line method),a best-fit line can be utilized to project a radius of influence of approximately 82 feet at 6 gpm (Appendx B) • Utilizing the Distance-Drawdown Method(Jacob straight-line method),a transmissivitywas calculated at 230 fl/day (equivalent to 1,740 gallons per day/ft) and a storativity value calculated at 0 026 (Appendix D) t • Based Ion a transmissivity value of 230 ft/day and an,aquifer thickness equal to 20 ft(screen interval at EW-2), a hydraulic conductivity value was calculated at 87 ft/day, or 0 031 cm/s (Appendix D), a hydraulic conductivity of 0 031 cm/s is consistent with a screened interval --located within silty sand or clean sand-(Appendix G)- �- • Laboratory analysis of extracted water collected during the pumping test detected elevated concentrations of TPH-g,TPH-d and BTEX(Table 3,Appendix E) Detected concentrations of target analytes were higher in the sample collected at 4 GPM than in the sainple collected at 5 GPM The higher pumping rate may be diluting contarninant concentrations by drawing more clean water'into the extraction well 1 o- - Advanced GeoEnvironmental,Inc I ,