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IVVATC A S S O C I A T E S I N C 2.0 SUBSURFACE INVESTIGATION METHODS AND PROCEDURES I To evaluate if groundwater extraction is a viable option for remediating petroleum impacted soil and groundwater, a soil boring was advanced approximately 25 feet south of the former UST location at the location shown on Figure 2. All field activities were performed in accordance with Foothill Engineering's Work Plan for Extraction Well Pump Test, dated April 12, 2000. This workplan was approved by S.ICEHD with modifications. ' 2.1 Drilling Activities ' Hollow stern auger drilling was conducted on October 8, 2001, by Spectrum Drilling {State C57 license no. 512268). Soil boring EW-1 was advanced to 61.5 feet and was completed as a six- inch diameter groundwater extraction well. A soil sample was collected from the boring at 60 ' feet bgs, but due to a miscommunication with the analytical lab the holding time expired and the sample was not analyzed. A field geologist logged the soil sample utilizing the Unified Soil Classification System. The cored sample was characterized for soil type, moisture content, and ' visual evidence of petroleum hydrocarbons. The soil sample was field screened with a Flame Ionization Detector (FID) for the presence of volatile organic compounds. A description of soil types encountered is included on the well construction log contained in Appendix A. Drill M cuttings were temporarily stored on site in 55-gallon DOT approved steel drums. i 2.2 Groundwater Extraction Well Construction 1 Soil boringEW-1 was completed as a six-inch diameter groundwater extraction well to be used p in the groundwater extraction and treatment pilot test. The screen interval of the extraction well 1 was positioned from approximately 50 feet bgs to 60 feet bgs. The screen slot size was 0.020- inch. The well construction details for well EW-1 are shown on the well construction log 1 contained in Appendix A. 223 Extraction Well Development Groundwater extraction well EW-1 was surge blocked on October 22, 2001 by Spectrum Drilling. The groundwater extraction well was developed by ATC on November 7, 2001. The well was purged until the extracted water was relatively sediment free. Development logs are included in Appendix B. Purgewater was temporarily stored on site in 55-gallon drums. 3.0 GROUNDWATER PUMPING PILOT TEST A groundwater pumping test was proposed in Foothill Engineering's Work Plan for Extraction ' Well Pump Test, dated April 12, 2000. The goal of the groundwater pumping test was to provide aquifer data necessary to characterize the feasibility of operating a groundwater treatment system at the site by providing the following parameters: wA259571repom\pumptest,doc 2