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CAMBRIA TECHNICAL RATIONALE FOR PROPOSED SCOPE OF WORK • The vertical extent of impacted soil and groundwater beneath the site has not been delineated. • The lateral extent of impacted groundwater has not been delineated. • Cambria proposes to install one soil boring adjacent to the USTs and northwestern dispenser to assess the vertical extent of impacted soil and groundwater. • Cambria proposes to install three groundwater monitoring wells to determine groundwater flow direction and gradient and to investigate the lateral extent of impacted groundwater. WORK TASKS Permits: Cambria will obtain a well permit from SJCPHS/EHD. Site Safety Plan: Cambria will prepare a Site Safety Plan for field work. Utility Clearance: Cambria will mark proposed drilling locations and will clear the locations through Underground Service Alert prior to drilling. Site Investigation: One exploratory soil boring (CPT-1) is proposed at the location shown on Figure 2. The boring will be advanced using cone penetration test (CPT) equipment. The purpose of this boring is to assess the vertical extent of impacted soil and groundwater identified in previous investigations in the vicinity of the USTs and the northwestern dispenser. This boring will be advanced to a depth of 90 fbg. First encountered groundwater, based on quarterly monitoring, is between 50 to 60 fbg. Cambria also proposes three hollow-stem auger borings (MW-2 through MW-4), which will be converted to groundwater monitoring wells, at the locations shown on Figure 2. The purpose of these wells is to assess the lateral extent of impacted groundwater. Well MW-2 is located north of the USTs, and wells MW-3 and MW-4 are proposed south of the USTs, in the presumed downgradient direction,based on information provided by SJCPHS/EHD staff. A Cambria geologist will supervise the drilling. Soil from boring CPT-1 will be logged continuously using electronic CPT equipment to a depth of 90 fbg. Soil samples from this boring 1359 3