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PHASE II ENVIRONMENTAL SITE ASSESSMENT INVESTIGATION WORK PLAN APN 139-250-030 206 N. SUTTER STREET STOCKTON, SAN JOAQUIN COUNTY, CALIFORNIA August 4, 2022 1.0 INTRODUCTION This work plan was prepared by Condor Earth (Condor) to describe proposed Phase II Environmental Site Assessment (Phase II ESA) investigation activities at 206 N. Sutter Street, Stockton, California Assessor Parcel Number (APN) 139-250-030 (Site, Figures 1, 2, 3, and 4, Appendix A). The purpose of the work is to investigate to subsurface soil and groundwater at the Site to evaluate whether historical use as a commercial fueling station has resulted in contamination beneath the Site. The Phase II ESA Investigation Work Plan will be conducted for the San Joaquin County Office of Education (Client). The proposed work includes advancing a up to seven (7) direct push borings to an estimated depth of approximately 25 to 80 feet below ground surface (bgs) to investigate whether subsurface soil and/or groundwater contamination is evident at the Site and to collect soil and groundwater samples for laboratory analyses as indicated in Figure 3. All work will be performed by a State-licensed (C-57 drilling license) drilling contractor under supervision of a Condor geologist. 2.0 PROJECT BACKGROUND The Site is designated as APNs 139-250-030 located at 206 N. Sutter Street, in Stockton, San Joaquin County, California. Condor discovered that, based on review of historical documents, the Site appears to have had a commercial fueling station in the southwestern portion of the Site from approximately the 1930s until the 1960s. The Ambassador Hotel was constructed over the gas station and was recently demolished. In February 2017, two geotechnical borings were advanced at the Site as part of a larger geotechnical engineering study for the Ten Space Development Project in downtown Stockton. Boring B-3 was terminated at approximately 10 feet bgs due to a concrete obstruction and B-4 indicated samples had a smell of gasoline starting at about 30 feet down to 50 feet bgs. Site boring logs B-3 and B-4 are included in Appendix B. 3.0 SUBSURFACE INVESTIGATION PLAN Condor will conduct the Phase II ESA based upon the locations of former Site features of the commercial fueling station as identified in historical fire insurance maps (Figure 3 and 4, Appendix A). A utilities location service subcontractor will be utilized to identify the position of potential underground utilities within a 25 square feet area around the proposed boring locations. Condor will advance up to seven (7) borings to an estimated depth of approximately 25 to 80 feet bgs to investigate whether subsurface soil and/or groundwater contamination is evident at the site. Based upon information obtained from recent geotechnical borings at the Site, shallow groundwater at the site is expected to be present at a depth of approximately 25 feet bgs. Soil samples will be collected in 5-foot intervals from continuous core for the purpose of characterizing the lithology and evaluating contaminants in subsurface soils. Three groundwater samples will also be collected at the Site. Condor will utilize a State-licensed (C-57 drilling license) drilling contractor to conduct the drilling and groundwater sampling. We anticipate using a drill rig equipped with direct push capability, which will minimize soil cuttings generated during the investigation. Any soil cuttings generated during the