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EpM_ATA IX <br /> SECOND QUARTER 2004 <br /> GROUNDWATER MONITORING REPORT <br /> UST Site No 3 — Port of Stockton <br /> Stockton, Califorrua <br /> 1.0 INTRODUCTION <br /> This report summarizes the second quarter 2004 groundwater monitoring event at Port of <br /> Stockton's (Port) former underground storage tank (UST) Site No 3 Monitoring was performed <br /> on May 21, 2004, by WGR Southwest, Inc (WGR), in accordance with directives from the local <br /> enforcement agency, San Joaquin County Environmental Health Department (END) <br /> UST Site No 3 is located near the central portion of the Port in the City of Stockton, San Joaquin <br /> County, California, approximately 50 feet north of Port Road G and about 300 feet west of Port <br /> Road 14 (Figures 1 and 2) The site is catalogued by EHD as Site Code 1282-124 <br /> The site formerly contained two 12,000-gallon USTs, both of which stored unleaded gasoline <br /> 40 (Figure 2) The tanks were removed in 1988, along with approximately 180 cubic yards of soil <br /> excavated to a depth of about 11 feet below ground surface (bgs) Detailed descriptions of the <br /> site, the site investigation history, and the site hydrogeologic setting are available in the Results <br /> of Additional Assessment and Remediation Evaluation of Petroleum Hydrocarbons in <br /> Groundwater (Geomatnx, 2003) <br /> The site is located on the delta of the San Joaquin Raver, approximately 2 miles east of the <br /> confluence of the San Joaquin and Calaveras rivers The subsurface geology consists of a thick <br /> sequence of alluvial deposits of late Tertiary to Holocene age overlying sedimentary rocks of <br /> Cretaceous to Tertiary age, which in turn overlie crystalline basement rocks Site-specific data <br /> collected to a maximum depth of 49 feet bgs indicate a soil profile consisting of interbedded sand <br /> and clay layers Since 1999, depth to groundwater beneath the site has ranged from 9 to 16 feet <br /> bgs Groundwater beneath the site is confined to semiconfined <br /> 2.0 FIELD PROCEDURES <br /> A total of six groundwater monitoring wells are used to monitor groundwater quality below the <br /> site Groundwater samples were collected by WGR from five groundwater monitoring wells <br /> (MW3-1, MW3-2, MW3-4, MW3-5, and MW3-6) As during the fourth quarter 2003 and first <br /> quarter 2004, well MW3-3 could not be sampled because it was covered with about 2 5 feet of <br /> 11PROIEC f 060s\6437 OVA6417 21 doc l <br />