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and Nilsen, 1990). Based on data from nearby studies within the Port area, the soil profile ' <br /> at the site to a depth of about 20 feet bgs consists of interbedded, sands and clays, mostly <br /> under reduced conditions (Sierra-Pacific Groundwater Consultants [SPGC], 1994). <br /> Data from nearby studies indicate that the current depth to groundwater in the vicinity ranges - <br /> from about 5 to 10 feet bgs (SPGC, 1998, and EMCON, 1998) Seasonal fluctuations in the <br /> water table appear to range from about 3 to 5 feet, with some as much as 6 to 9 feet 1 <br /> Historically, water levels in this area have risen as much as 8 feet since 1994 Tank removal <br /> inspection records for Port sites (dating back to 1987) indicate that no groundwater was ' <br /> encountered during excavation or soil resampling to a depth of as much as 16 feet bgs <br /> Groundwater flow directions in the vicinity of the site appear to be variable, ranging from west <br /> northwest to east southeast Flow direction changes may be due to tidal influences produced ' <br /> by the deep water channel to the north and the San Joaquin River to the west and southwest <br /> of the Port area <br /> 3.0 PROPOSED SCOPE OF WORK , <br /> The proposed scope of work includes advancing three borings each at Site 2 and Site 3, using <br /> the Geoprobe direct-push method, and collecting soil and/or groundwater samples for analysis <br /> of PHCs Field, analytical, and histoncal data will be evaluated to determine the lateral and <br /> vertical extent of PHC impact in the soils and groundwater beneath each site. A Site <br /> Investigation and Evaluation Report_will be prepared includingdocumentation of field work , <br /> and a summary of findings and recommendations. <br /> 3.1 FIELD INVESTIGATION <br /> The following sections describe the approach and methodology for the field investigation <br /> Prior to initiating any field work, an application for "Permit to Construct Monitoring Wells ' <br /> and/or Soil Borings for the Purpose of Subsurface Investigation," will be submitted to and <br /> approval obtained from the PHS/EHD <br /> 3.1.1 Approach <br /> Water levels in the vicinity of the site have risen substantially since the tanks were removed <br /> It is anticipated that there will be only a small interval, if any, of unsaturated soils (vadose <br /> zone) between the bottom elevation of the former excavations and the water table If that <br /> 4 '981171S23US1'IN WPN <br />