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' Quarterly Report - Fourth Quarter 2002 <br /> TOP FILLING STATION <br />' 101 South Wilson Way, Stockton, California <br />' 1.0. INTRODUCTION AND SCOPE OF WORK <br />' Advanced GeoEnvironmental,Inc (AGE)has prepared this quarterly report for 101 South Wilson Way <br /> (the site),Stockton,California The site setting is illustrated on Figure 1 Site structures and monitoring well <br /> locations are depicted on Figure 2 <br /> The objective ofthe work was to monitor dissolved petroleum hydrocarbon concentrations in groundwater <br /> and to characterize ground water flow direction and gradient on the site This report has been prepared in <br /> Iaccordance with gwdehnes issued by the California Regional Water Quality Control Board-Central Valley <br /> Region(CVRWQCB)for investigation ofunderground storage tank(UST)sites A summary ofprevious <br /> investigations at the site was included in the AGE-prepared Quarterly Report- Th and Quarter 2002, <br /> dated 13 December 2002,groundwater monitoring data acquired to date is included in the tables of this <br /> report <br /> I <br /> 2.0. MONITORING AND SAMPLING PROCEDURES <br /> A quarterly groundwater monitoring event was performed at the site on 04 December 2002 Groundwater <br /> monitoring procedures for the site were outlined in Work Plan Adendum-June 2001, dated i 1 June <br /> 2001 and approved by the San Joaquin County Environmental Health Department(EHD)by letter dated <br /> 07 July 2001 <br /> 2 1 WELL MONITORING AND EVACUATION <br /> Depth to ground water was measured in each well from the top ofthe well casing to the nearest 0 01-foot <br /> utilizing a Solinst water level meter,ground water was not encountered at wells VW-1 A,VW-1 B,VW-213 <br /> Iand VW-313 and was reported as"dry" The ground water elevation at wells MW-1 through MW-7, <br /> VW-I C,VW-2A and VW-3 A were calculated by subtracting the measured depth to ground water from <br /> the surveyed casing elevation As-built monitoring well construction details are summarized in Table 1, <br /> ground water elevations were plotted and contoured on a scaled site map (Figure 3) <br /> I After water levels were measured,approximately 13 to 18 gallons of ground water(a mirumum of three <br /> casing-water volumes per well)were evacuated(purged)from wells MW-1 through MW-5 utilizing a <br /> submersible Grundfos pump,approximately 9V2.to 10 gallons of ground water were purged from wells <br /> VW-1 C,VW-2A and VW-3A utilizing disposable polyethylene bailers Temperature,pH and conductivity <br /> were measured for stabilization at regular purge-volume intervals from each well using an Oakton water <br /> Advanced Geo Environ mental,Inc <br /> 1 <br />