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As described in Section 3.1.1 above, the locations will be drilled and assessed for the presence of <br /> floating hydrocarbon product before proceeding with the installation of a well and recovery <br /> equipment. A boring will be advanced using a hollow stem auger using procedures defined in <br /> Appendix A. Temporary,2-inch well casing will be placed into the boring and liquid levels will <br /> be allowed to equilibrate for 24 hours. Depth to product and depth to water will then be <br /> measured to determine whether adequate product thickness is present to warrant the installation <br /> of product recovery equipment. If product thickness at any of these locations is less than 0.25 <br /> feet after 24 hours, the installation of the well at that location will be reassessed and the well may <br /> be relocated. Well construction procedures are provided in Appendix A. <br /> 3.1.4 Phase 4- Dissolved Phase Remediation <br /> After the bulk of the floating product has been removed, it will be necessary to address the <br /> dissolved phase impacts resulting from unrecoverable thickness of residual product and <br /> petroleum sorbed to soils in the in vadose zone. This task comprises Phase 4. In anticipation of <br /> accelerated product recovery with the initiation of pumping from well EW-2 in October 2002, <br /> LFC submitted a work plan entitled Draft Proposed Remediation System Enhancements and <br /> Recommended Modifications to Monitoring and Reporting Program, dated Se[te,ber 22, 2003 to <br /> the RWQCB address these impacts. Depending on groundwater level and concentration trends, <br /> the oxygen injection well locations and monitoring points may be revised to optimize system <br /> performance. Where appropriate, monitored natural attenuation may be used at on-site locations, <br /> provided that downgradient migration of diesel does not exceed the beneficial use level for diesel <br /> in groundwater. The system described in the Oxygen Injection Work Plan will be used to <br /> mitigate and control residual dissolved phase impacts downgradient of the plant boundary. <br /> Because the recovery wells show adequate gradient control, implementation of the oxygen <br /> injection system is planned after most of the free product has been removed. <br /> 3.1.5 Phase 5—Monitoring, Reporting and Site Closure <br /> Monitoring and reporting under Phase 5 will act to document remediation effectiveness and <br /> ultimately, to demonstrate that remediation goals have been attained. Because the Cleanup Plan <br /> involves installation of new wells and changes to the existing remediation system over time, <br /> changes to the existing MRP will be recommended to the RWQCB as necessary to provide a <br /> focused monitoring program. Generalized remediation goals for the facility include removal of <br /> as much floating product as is reasonably practical, then demonstrating that residual diesel <br /> concentrations in the groundwater system have declined to acceptable levels. <br /> Upon achievement of these goals, LFC will petition the RWQCB to deactivate the appropriate <br /> remediation system and ultimately grant a no-further-action determination for the site. <br /> GeoTrans <br /> 7 <br />