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Kristi Shelton Page 3 November 1,2007 Objective This work plan is submitted as agreed with the RWQCB at the September 21,2007,meeting to document the methods that will be used to destroy the 10 SVE wells (SVE-1 through SVE-10) and 4 deep groundwater monitoring wells (N-21 through N-24). The objective of destroying these wells is that they are no longer needed for the following reasons: • SVE Wells. Operation of the SVE wells was discontinued when the active remediation systems(SVETS,GWETS) were shut down on February 5,2004,to begin the 3-year bioremediation pilot study. As noted above,the aboveground portions of the SVETS and GWETS have been removed from the Site as approved by the RWQCB. The SVE wells are no longer necessary because future remediation will rely on MNA as enhanced with the phytoremediation system. • Deep Groundwater Monitoring Wells. Monitoring groundwater from these wells is no longer necessary because hydrocarbon constituents from the 1986 pipeline release are not ro__u_tinely detected in these wells. The shallow groundwater monitoring wells will remain to document future groundwater conditions as MNA and phytoremediation continue. As approved by the RWQB, monitoring wells M-9 and N-6 and extraction well RW-2 were destroyed in 2004 because monitoring wells M-9 and N-6 were routinely dry,and extraction well RW-2 was screened within a clay layer providing low yield (CH2M HILL, 2005b). The former wells are shown in Figure 2. Scope of Work The following work will be performed to destroy the 10 SVE wells (SVE-1 through SVE-10) and 4 deep groundwater monitoring wells (N-21 through N-24): • Permit Application. A well destruction permit application will be prepared and submitted to the San Joaquin County Environmental Health Department(EHD). Well destruction will not commence until a permit is received and arrangements have been made for an EHD inspector to be present during the well destruction work. • Well Destruction. The wells will be over-drilled to their total depth using a hollow-stem auger drill rig. The construction of each of the wells is provided in Table 1, and copies of the construction logs for each of the wells are attached to this work plan. Each of the over-drilled boreholes will then be backfilled with neat cement grout. The grout will be tremied into the borehole as the augers are removed. Downhole equipment will be decontaminated using a steam cleaner after the abandonment of each well. • Waste Management. Subsurface materials removed during over-drilling will be placed into 55-gallon Department of Transportation (DOT)-approved drums. Representative ES 102007015SCO/HOLT_WORK_PLAN_LETTER_WL369.DOC/073050005 COPYRIGHT 2007 BY CH2M HILL,INC.•COMPANY CONFIDENTIAL