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' 10 December 2001 AGE NG Project No 95-0143 ' Page 4 of 10 ' MW-9 (located 140 feet toward the north) at 0 08 feet after 350 minutes of purnpmg operation ' The maximum ground water draw-down in the seven observation wells versus the distance of each well from the extraction point were graphed on semi-logarithmic paper(Appendix B) Inferred radii ' of influence of 100 feet (6 gpm), 120 feet (8 gpm) and 120 feet (10 gpm)were determined utilizing the semi-loganthmuc plots of draw-down versus distance(Appendix B) Ground water levels In the observation wells all appeared to be influenced and had measurable draw-down during each step of the pumping test However, decreased draw-down(increased ground water elevation) was noted In observation wells VW-1, MW-7, VW-4 and MW-9 during the 10 gpm test after 410 minutes of pumping operation(165 minutes of pumping at 10 gpm) At 480 minutes of pumping operation(235 ' n-nnutes ofpumping at 10 gpm), decreased draw-down was observed in each of the observation wells and the top of the pump was exposed In addition, the extracted water discharged from the pump contained significantly more fine-grained material than had been noted at 6 and 8 gpm Decreased draw-down may be related to a shift from laYrnnar flow to turbulent flow conditions at the extraction well Results of the aquifer ground water pumping test are summarized in Table 2 An optimum pumping rate of 8 gpm was determined based on the inferred radius of influence and the relatively stable pumping conditions observed during the 8-hour test 3 1 2 Extracted t acted Water Sampling Procedures Nine grab ground water samples were collected prior to discharge into the Baker tank Three samples were collected during each step of the variable rate pumping test, one at the beginning, one near the middle and one at the end of the step The samples were collected as follows • Sample EW-3/08 30 was collected after 20 minutes of pumping at 6 gpm, • Sample EW-3109 15 was collected after 65 minutes of pumping at 6 gpm, • Sample EW-3/10 15 was collected after 135 minutes of pumping at 6 gpm, • Sample EW-3/10 25 was collected immediately after increasing the pumping rate to 8 gpm (total pumping duration of 145 minutes), • Sample EW-3/11 45 was collected after 80 nunutes of pumping at 8 gpm (total pumping duration of 225 minutes), • Sample EW-3/12 25 was collected after 120 minutes of pumping at 8 gpm.(total pumping • duration of 265 minutes), Advanced GeoEnwronmenta4 Inc