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06/24/2002 15 42 2094671118 AGE STOCKTON PAGE 07 31 January 2002 AGB-NC Project No 95-0128 Page 6 of 8 aboveground stoi age Baker tank into a vacuum truck(supplied by American Valley Waste Oil), the purged water was transported off-site under hazardous waste manifest to Industrial Service Oil Co Inc , a waste treatment facility located in Los Angeles, California Documentation and uniform hazardous waste manifest for disposal of the pump test purged grater are contained in Appendix I 3 5 GEO-TECHNICAL ANALYSIS RESULTS OF SOIL SAMPLES Silty clay to sandy clay was genei ally encountered frotm a depth of approximately 30 feet to 60 feet bsg in the two soil borings S oil borings and well corz>pletron logs ai a depicted in Appendix A. Based upon soil samples submitted fox geotechnical analysis, clay or clay with fine sand was encountered between 35 and 50 feet bsg The clay had a permeability range of 1X10' crwsec to 3X10' crn/sec, and average porosity of 43% (Appendix J) 4.0. SUMMARY AND CONCLUSIONS The gi ound water table occurs ed within the well sci een interval ofthe extraction well The most likely • sour ce of the extracted ground water was from the silty clay and sandy clay with low permeability, encountered from 30 feet to 60 feet bsg The results fiom the October 2001 aquifer ground water pumping test are Ground water draw-down of at least 8 5 feet was observed in extraction well EW-1 following 720 nu nutes of continuous purrnptag(5 GPM),groundwater draw-downwas observed m well VW-1 (located 5 feet to the west ) at 1 2 feet,well VW-4 (located 30 feet toward the west) at 0 45 feet,well EW-2 (located 15 feet toward the northeast) at 0 65 feet, wells MW-4 and MW-5 (located 70 feet toward the northeast and 60 feet to the east,respectively)at 0 23 feet and in well vapor well VW-3 (located 25 feet toward the east) at 0 8 feet (Appendix C) • A semi-logarithmic plot of ground water di aw-down vs time was plotted to demonstrate relative stabilization of the gi ound water table within the network of observation monitoring points (Appendix E) • Utilizing a serru-logarithmic plot of ground water- draw-down vs observation well distance firoxm the purnpxng well, a best-fit brie can be utilized to project a x adius of intercept for non- influence of approximately 100 feet at 5 GPM (Appendix F) • Utilizing the Dxstance-Di awdown Method, a transrnissivity was calculated at 380 ftt/day (equivalent to 2,840 gallons per day/ft) and a storativity value was calculated at 0 043 (Appendix G) • Based on a trarnsmxssxvxty value of 308 ft'/day and the extraction well screen thickness equal to 30 ft(screen interval at EW-1), ahydraulic conductivity value was calculated at 94 ft/day, of 0 03 cm/s (Appendix G), a hydraulic conductivity of 0 03 cm/s is consistent with a 4dvanced Geornvlronmontnl Inc