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The groundwater flow direction was calculated to be towards the east at an average gradient of <br /> . 0.0026 ft/ft. An eastward groundwater flow direction is consistent with previous quarters. The <br /> groundwater elevation has decreased by more than 1.5 feet across the site since the previous sampling <br /> event (December 2001). <br /> A Delta technician conducted six site visits to optimize and maintain the SVEIAS system. The SVE <br /> system was restarted on January 8, 2002, after allowing the soil vapor concentrations to rebound. <br /> Approximately 173.08 lbs of TPHG as gasoline was removed during the first quarter 2002, and a <br /> cumulative mass of 1,449.62 lbs since startup (09128100). The SVE and AS systems were not operational <br /> between March 4, 2002, and March 18, 2002, due to a power outage. Delta will optimize the operation of <br /> the SVE system by increasing flows, and therefore influent concentrations, by changing the vacuum and <br /> flows from the individual wells. Due to high groundwater elevations, only approximately 5 feet of screen is <br /> available for vapor extraction. The SVE system was in compliance with San Joaquin Valley Unified Air <br /> Pollution Control District permit to operate. <br /> The air sparge system was also restarted on January 8, 2002 along with the SVE system. During the first <br /> quarter 2002, Delta injected ambient air in three sparge wells (AS-1 through'AS-3) at flow rates in the <br /> range of 0.33 to 0.66 cubic feet per minute (cfm)at approximately 15 pounds per square inch (psi). <br /> ATTACHMENTS: <br /> • Table 1 Groundwater Monitoring Data <br /> • Table 2 Groundwater Analytical Results for Oxygenates and Additional Compounds <br /> • Table 3 Floating Product Monitoring Summary, Well VW-5D <br /> • Table 4 Operational Uptime Information of the Soil Vapor Extraction System <br /> • Table 5'' Flow Rates and Analytical Results of Air Sample Analyses <br /> • Table 6 Extraction and Emission Rates <br /> • Figure 1 Site Location Map <br /> • Figure 2 Groundwater Elevation Contours, 1"Quarter 2002 <br /> • Figure 3 Groundwater Analytical Summary, 15t Quarter 2002 <br /> Figure 4 Influent Concentrations vs. Time <br /> • Figure 5 Cumulative Mass Removed vs. Time <br /> • Appendix A Field Data Sheets <br /> • Appendix B Sampling and Analysis Procedures <br /> Appendix C Certified Analytical Reports and Chain-of-Custody Records <br /> P:\ARCO\0548\QTRLY\20021Arca_0548_1Q02.doc Delta <br />