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r INTRODUCTION ' This Project Status Report of Groundwater MonitoringP provides groundwater quality monitoring J P information and data for gasoline impact from 2 former 12,000-gallon USTs The groundwater monitoring activities discussed herein were conducted in general accordance with the "Workplan for Initial Subsurface Investigation," (BoyaJian & Ross, Inc [B&R], 1998) "Initial Subsurface Investigation of Petroleum Hydrocarbons," (B&R, 1998), and the "Workplan for Additional ' Subsurface Site Investigation for Petroleum Hydrocarbons,"(Philip P Ross, R G Consulting Hydrogeolognst, January 10, 1999) implemented as approved by the San Joaquin County Environmental Health Division(SJCEHD) 1 The work described in the Groundwater Monitoring section documents sounding and sampling ' activities conducted on May 17, 2000 The History of Site Work (beginning on page 2) summarizes previous work performed on the subject ' site, as do the tables listing well-sounding data, and groundwater sampling analytical results Previously-submitted documents by the Port of Stockton (Port), and earlier consultants present historical information in greater detail SITE SETTING The property is located at the central portion of the Port in the City of Stockton, San Joaquin County, California (see Figure 1) This site, along with Site 2, has been identified by SJCEHD as "Site Code 1282-124" Site 2 was determined to require no further investigations by SJCEHD Site 3 is approximately 50 feet north of Port Road G and about 300 feet west of Port Road 14 (see Figure 1) Following is a description of the tanks, as well as excavation, soil., and groundwater sampling activities at Site 3,which is the subject of this report The site was formerly occupied by two 12,000 gallon tanks, identified on a SJCEHD inspection report ' as Tank #1 and Tank # 4, both of which contained unleaded gasoline The tanks were removed on February 16, 1988 by Stockton Service Station Equipment Co , Inc (SSSE) Approximately 180 cubic yards of soil were excavated with the tanks to a depth of about 11 feet below surface grade ' (bsg) Presently,the area over the former tanks and excavation is covered with concrete A survey of domestic, municipal, agricultural,industrial and other supply wells within a 2,000-foot radius of the site was conducted No municipal or drinking water supply wells were identified within the 2000-foot ' radius ' LOCAL HYDROGEOLOGIC SETTING The site is located on the Delta of the San Joaquin River, approximately 2 miles east of the confluence ' of the San Joaquin and Calaveras Rivers The subsurface geology consists of a thick sequence of . alluvial deposits of late Tertiary to Holocene Age, overlying sedimentary rocks of Cretaceous to Tertiary age, which in turn overlie crystalline basement rocks (Bartow and Nilsen, 1990) Data from 1 tut sttO gtr4 dm r