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Appendix B Advanced AGE Project No. 99-0559 Environmental Page 2 of 12 n.M 9 On 22 February 1999, approximately 100 cubic yards of hydrocarbon-impacted soil was excavated and approximately 125 cubic yards of hydrocarbon-impacted stockpiled soil were hauled from the site to BFI Vasco Road Landfill (BFI) in Livermore for disposal. Following soil excavation and removal, additional soil was excavated for the new UST installation. Soil samples were collected from the enlarged excavation by AGE and four soil samples from the new stockpile for the purpose of characterization for disposal. INITIAL SITE ASSESSMENT On 14, 15, 16 and 17 December 1999, AGE advanced four soil probe borings at the site. Probe boring B1 was advanced in the area of the behind the current store location south of the UST locations to a total depth of 52 feet below surface grade (bsg). Probe boring B2 was advanced in the area between the current USTs to a total depth of 45 feet bsg. A third probe boring, B3, was advanced northeast of the UST area to a total depth of approximately 62 feet bsg. Probe boring B4 was advanced approximately 10 feet north of former UST area to a total depth of 50 feet bsg. Samples were collected at five-foot intervals in each probe boring. Grab groundwater samples were collected from probe borings B3 and B4. The samples were collected utilizing a Geoprobe water sampling assembly fitted with a pre-cleaned one-inch diameter 0.01-inch slotted temporary well screen. The most intensely fuel component-impacted (methyl-tertiary butyl ether: MTBE) soil was in the area of borings B2, MW-2, and MW-3 at depths as great as 65 feet. A significant mass of hydrocarbons was present in the vicinity of well MW-2 from 15 feet to 65 feet bsg and to a lesser degree south of the former USTs, in the area of well MW-3, from 45 feet bsg to 65 feet bsg. INSTALLATION OF MONITORING WELLS On 25 and 26 January 2000, four groundwater monitoring wells MW-1 through MW-4 were installed to a depth of 65 feet bsg at the site. On 27 September and 01 through 03 October 2001, four Continuous Multichannel Tubing (CMT) groundwater monitoring wells MW-5 through MW-8 were installed. Monitoring well MW-5 was installed at the western property boundary, well MW-6 was installed at the southern property boundary, well MW-7 was installed directly east of the UST release and well MW-8 was installed east of the site. The location of CMT wells are illustrated in Figure 2. The CMT monitoring wells were designed and constructed utilizing five separate filter pack intervals, from 45-65 feet bsg, 87-100 feet bsg, 125-135 feet bsg, 148-160 feet bsg and 174-185 feet bsg, to characterize groundwater gradient, potential contaminant migration pathways and to assess the lateral and vertical extent of impacted groundwater west and east of the former UST release.