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Lithologic data at Site 3 indicate that, in general, the interval from roughly 13 to 23 feet bgs beneath the former tanks comprises mostly silt, clayey silt, and clay Silty sand occurs below this interval, ' which grades downward into loose, dark gray to greenish-gray, poorly-graded sand This dark gray sand was observed in all three bonngs from approximately 30 to 41 feet bgs, the total depth ' explored during this investigation Data from nearby studies indicate that the current depth to groundwater in the vicinity ranges from ' about 5 to 10 feet bgs(SPDC, 1998, and EMCON, 1998) Seasonal fluctuations in the water table appear to range from about 3 to 5 feet,with some as much as 6 to 9 feet Tank removal inspection records for Port sites (dating back to 1987) indicate that no groundwater was encountered during ' excavation or soil resampling to a depth of as much as 16 feet bgs Water levels in this area have risen as much as 8 feet since 1994, 2 to 3 feet of which appear to be attributable to the heavy and ' prolonged El Nino rainfalls of last winter Water levels measured in the three borings at Site 3 on August 7 ranged from about 9 5 to 12 feet bgs Based on nearby studies (SPGC, 1998 & EMCON, 1998) groundwater flow directions in the vicinity appear to be variable, ranging from west , northwest to east southeast Flow direction changes may be due to tidal influences produced by the deep water channel to the north and the San Joaquin River to the west and southwest of the Port ' complex 3.0 PROPOSED P SCOPE OF WORK The proposed scope of work includes advancing three borings, one in the vicinity of the USTs, one ' in the vicinity of the dispenser, and one in the northwest corner of the site, using the hollow-stem auger method Each of these bonngs will be completed as a monrtonng well and developed , Subsequently, each well will be sampled on a quarterly basis for analysis of PHCs and determination of groundwater gradient In addition, a supply well survey will be conducted in the vicinity of the site to evaluate the effects of potential migration of PHCs from the site A Technical Report will , be prepared including documentation of field work, results of the initial groundwater sampling, and a summary of findings from the supply well survey 1 This work plan will be carried out under the supervision of a California registered geologist The procedures for completing the scope of work are summarized in the following subsections ' 3.1 INSTALLATION OF MONTTORING WELLS ' Prior to initiating any field work, an application for"Permit to Construct Monitoring Wells and/or ' Soil Borings for the Purpose of Subsurface Investigation," will be submitted to and approval &3„dcl„„%-M 4 PHILIP P. Ross, R.G. '