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<br /> <br />PHASE II ENVIRONMENTAL SITE ASSESSMENT <br />INVESTIGATION WORK PLAN <br /> <br />APN 149-062-150 <br />401 SOUTH EL DORADO STREET <br />STOCKTON, SAN JOAQUIN COUNTY, CALIFORNIA <br /> <br />February 18, 2022 <br /> <br />1.0 INTRODUCTION <br />This work plan was prepared by Condor Earth (Condor) to describe proposed Phase II Environmental Site <br />Assessment (ESA) investigation activities at 401 South El Dorado Street, Stockton, California (Figures 1, <br />2, 3, and 4, Appendix A). The purpose of the work is to investigate to subsurface soil and groundwater at <br />the Site to evaluate whether historical use as commercial fueling stations and a former auto wrecking yard <br />has resulted in contamination beneath the Site. The Phase II ESA Investigation Work Plan will be <br />conducted for the Housing Authority of the County of San Joaquin (Client). <br /> <br />The proposed work includes advancing a total of eight (8) direct push borings. Five (5) borings to an <br />estimated depth of approximately 20-25 feet below ground surface (bgs) to investigate whether <br />subsurface soil and/or groundwater contamination is evident at the Site and collect soil and groundwater <br />samples for laboratory analyses and three (3) borings to 5 feet bgs along the southern portion of the Site <br />for laboratory analyses. All work will be performed by a State-licensed (C-57 drilling license) drilling <br />contractor under supervision of a Condor geologist. <br /> <br />2.0 PROJECT BACKGROUND <br />The Site comprises approximately 0.92 acres designated as APNs 149-062-150 located at 401 South El <br />Dorado Street, in Stockton, San Joaquin County, California. Condor Earth (Condor) discovered that, <br />based on review of historical documents, the Site appears to have had commercial fueling stations in the <br />eastern portion of the Site from approximately the 1940s until the 1970s and in the western portion of the <br />Site from approximately the 1950s to the late 1970s. Underground storage tank (UST) removal records in <br />the form of a permit to remove five USTs in 1985 were found for the Site address. No other records kept <br />by the San Joaquin Environmental Health Department (EHD) were found for the Site. The strip mall <br />currently located on the Site appears to have been constructed in the late 1980s. No documents pertaining <br />to an UST removal were located for the western portion of the Site (formerly 2 East Sonora Street). As a <br />result, Condor conducted a shallow soil gas investigation in December 2019 on the former gas station in <br />the western portion of the Site and found no evidence of a release. Condor recommends further due <br />diligence with a subsurface investigation to evaluate whether contamination is present. The Client <br />provided Condor with a Preliminary Geotechnical Information report by MatriScope, dated January 5, <br />2022. Two geotechnical boring were advanced on the western portion of the Site where new construction <br />is proposed. The Two exploratory borings were advanced to to depths of 16.5 feet and 51.5 feet below <br />ground surface (bgs) in the northeast and southwest corners of the vacant portion of the Site, respectively. <br />Groundwater was encountered at approximately 20 feet bgs. <br /> <br />3.0 SUBSURFACE INVESTIGATION PLAN <br />Condor will conduct the Phase II ESA based upon the locations of former site features of the commercial <br />fueling stations and auto wrecking yard, as identified in historical fire insurance maps. A utilities location <br />service subcontractor will be used to identify the position of underground utilities and evidence of tank <br />excavation backfill and/or any USTs that may remain buried at the Site. Condor will advance up to five (5) <br />borings to an estimated depth of approximately 20-25 feet bgs and three (3) borings to 5 feet bgs to