ARCHIVED REPORTS_SEPARATE PHASE HYDROCARBON INVESTIGATION UNOCAL EXTRACTION WELL PILOT STUDY 2011

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Stantec Report of Findings for the Waterfront Towers Separate Phase Hydrocarbon Investigation and Unocal Extraction Well Pilot Study Waterfront Towers Parking Lot March 4, 2011 drawdown of any significance was not observed in either well during the test. At 12:30 pm on November 16, 2010, pumping was initiated in GWE-2 while GWE-1 was still operating. On November 16, 2010 at 11:35 am, following 2.75 hours of GWE to 957 gallons total production, the submersible pump was shut down for adjustments due to diminished groundwater yield and recharge was measured. Within eight minutes of shut down, groundwater levels had rebounded from 15.40 to 13.70 feet bgs and approximately 13.70 feet bgs was maintained for an additional three readings over a 15 minute period until the submersible pump was restarted. Restart at 12:01 pm was followed by 16 minutes of GWE to 1,000 gallons total production (additional 43 gallons). The submersible was then shut down due to low groundwater production and recharge was measured. Within 85 minutes of that shut down, groundwater levels had rebounded from 15.02 to the 13.77 feet bgs (similar to the first rebound test). Approximately 13.30 feet bgs was maintained over a 20.2 hour period. GWE-1 was never restarted again. Note that the first rebound period identified above occurred with GWE-2 off and the second period was initiated when GWE-2 was on and extracting groundwater approximately 112 feet down slope of GWE-1 in the GCT. During GWE on GWE-1, the following selected chemical constituent mass was removed: • Approximately 0.013 lbs of TPHd were removed at a removal rate of 0.11 lbs/day. At <2.0 gpm that is a projected removal rate of less than 0.04 lbs/day. • Approximately 0.002 lbs of TPHg were removed at a removal rate of 0.02 lbs/day. At <2.0 gpm that is a projected removal rate of less than 0.01 lbs/day. • Approximately 4.5E-6 lbs of benzene were removed at a removal rate of 3.6E-5 lbs/day. At <2.0 gpm that is a projected removal rate of less than 1.3E-5 lbs/day. • Approximately 3.0E-4 lbs of TBA were removed at a removal rate of 2.3E-3 lbs/day. At <2.0 gpm that is a projected removal rate of less than 8.6E-4 lbs/day. GWE analytical data are presented in Table 5 and calculations of mass removal by GWE are presented in Table 7. Laboratory analytical reports and chain-of-custody documentation are included in Appendix I. 4.7 GWE-2 GROUNDWATER EXTRACTION TESTS DATA AND RESULTS GWE-2 was operated in the GWE mode for approximately 6.2 hours between November 16 and 17, 2010. Field notes are included in Appendix H. The following is a summary of the data collected during the test. The average GWE rate for GWE-2 was approximately 5.4 gpm with a total production of 2,041 gallons. Groundwater production rates decreased to approximately <4.0 gpm by the end of the test. Groundwater extraction data is presented in Table 3. The inlet of the submersible pump was set at approximately 15 feet bgs inside GWE-2. The depth-to-water prior to extraction was 13.02 feet bgs. During the GWE test on GWE-2, groundwater elevations in two wells (GWE-1 and MW-72) were monitored. Groundwater drawdown of any significance was not observed in MW-72 during the test; however; extracting 4.9