ARCHIVED REPORTS_WELL DESTRUCTION WORK PLAN

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2.4 WELL DESTRUCTION There are 19 groundwater monitoring wells and 3 soil vapor wells at the site that will be properly destroyed. CRA plans to destroy 16 of the 19 monitoring wells by pressure grouting in accordance with the EHD well standards because these wells have not been impacted by the crude oil release from the former pipelines,based on historic groundwater monitoring data that is predominantly non-detect. Three of the monitoring wells (MW-2, MW-5A, and MW-15) and the 3 soil vapor wells will be destroyed by over-drilling. Pressure grouting will be performed by pumping hydrated cement into the monitoring well casing. The well head will be sealed and pressurized to force the grout into the filter pack. After the cement has set, the well cover/standpipe for each well will be removed, and a hole 1 foot larger in diameter than the original borehole will be excavated to a depth of approximately 3 feet below grade (fbg). The well casing will be cut off 2.5 fbg (6 inches above the bottom of the excavation). The well casing will then be filled with grout and the grout will be allowed to Spill over the top of the casing and fill the hole to a thickness of 1 foot (6 inches above the well casing). The hole will then be backfilled with soil to match the surrounding grade. The 3 soil vapor wells and monitoring wells MW-2,MW-5A, and MW-15 will be over-drilled to remove the well casing (or vapor well tubing), well seal, and filter pack sand. Prior to drilling, the upper 5 feet of each well will be cleared for underground utilities (using air vacuum technology,if necessary). A C-57-licensed drilling contractor will be retained to execute this work under CRA supervision. 2.5 REPORT PREPARATION After the field activities are completed CRA will generate a report documenting the well destructions and submit it to the EHD and RWQCB. 2.6 SCHEDULE CRA is moving forward with coordination of this work based on the RWQCB's verbal concurrence with the conceptual plan provided in our April 23, 2014 meeting and the need to move this work along expeditiously in support of the land development. We respectfully request the RWQCB expedite review of approval of this work plan for the same reason. Please contact CRA with any questions or concerns. 060223(32) 2 CONESTOGA-ROVERS&ASSOCIATES