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Geosyntec consultants performance monitoring points will include the SVE wells, the system influent, the system effluent, and soil vapor probe SG-100. The step-rate test will take place during the first one to two days of the pilot test. The process will involve increasing the vacuum at the SVE wells in five equal increments to a maximum anticipated vacuum of approximately 8 in-Hg, based on historical SVE data. During each step, the applied vacuum and extracted soil vapor flow rate from the well will be measured, as well as the observed vacuum at SG-100. Each step will be performed until near steady-state vacuum is observed at all monitoring points. Each step will be conducted for approximately one hour or until near steady- state vacuum response is achieved at the monitoring points. Following completion of the step-rate test, constant rate testing will be performed for 4 to 8 hours at the SVE wells at the maximum flow rate and vacuum established during the step-rate test. Based on the step and constant-rate testing results,an optimal flow rate and vacuum range will be selected for continuous operation for the remainder of the pilot test. Vapor samples during both the step and constant-rate tests will be collected in Tedlar bags and analyzed using a calibrated 10.6 electron volt (eV) photoionization detector (PID) capable of measuring PCE vapors. The PID will be fitted with a moisture trap to minimize interference. Following the conclusion of the constant-rate test and after routine operation for at least 24 hours, a sample will be collected from each monitoring point in 1-liter batch certified Summa®canisters with five-minute flow controllers and new Teflon tubing for VOC analysis. Samples will be shipped to a California National Environmental Laboratory Accreditation Program-certified laboratory under chain-of-custody procedures and analyzed for VOCs using U.S. Environmental Protection Agency method TO-15. Following the completion of the five-day pilot test, the SVE system will be shut down for performance monitoring. Implementation of additional SVE will be determined based on the results of the performance monitoring program described below. 4.5 Post-SVE Performance Monitoring After shutdown of the SVE system, soil vapor samples will be collected from the SVE wells and SG-100 using Summa® canisters. The first two performance monitoring samples are proposed to be collected 1-and 3-months after shutdown of the SVE system.As described above(Section 3.3), the timing for subsequent performance monitoring samples will be determined by the rate of rebound observed, if any, and may be variable. When the performance monitoring results show evidence of substantial rebound, i.e. increases during each subsequent performance monitoring event consistently exceeding the CHHSL in all the samples, the SVE system will be remobilized for additional SVE events. If results do not show significant rebound, additional samples will be collected to assess the rate of rebound at longer time intervals. The number and frequency of additional samples will depend on the rate of rebound observed, but no more than a total of three monitoring events after each SVE event is being planned. The duration of each additional SVE event after the initial pilot test will depend on the baseline concentrations prior to the event, and performance monitoring results at the SVE wells and SG- 100. This cycle of intermittent SVE followed by performance monitoring will be repeated until the soil vapor concentrations are consistently below the commercial CHHSLs or if performance Northern Parking Lot Remedial Plan 8 August 6,2021