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Mr. Maurice Benson - 4 - • 4 March 2009 <br /> Defense Logistics Agency <br /> area that would require LUCs must be assumed to be larger than is currently estimated <br /> in the Draft FS. This would increase the cost of the LUC alternative. <br /> 2. The cost of the LUC alternative should also include the installation and long-term <br /> operation costs of off-site groundwater monitoring. The Regional Water Board believes <br /> that the monitoring program presented in the Draft FS should include wells to monitor <br /> the down-gradient extent of dieldrin. The installation and operation costs of wells would <br /> increase the cost of the LUC alternative. <br /> 3. The Draft FS does not adequately estimate the costs associated with off-site land <br /> purchase or easement acquisition. In addition, the Draft FS does not present sufficient <br /> evaluation of the feasibility or legality of easement acquisition or LUC enforcement on <br /> off-site property. <br /> 4. If the LUC alternative is adopted and the dieldrin ACL could not be met in a reasonable <br /> amount of time, the Draft FS will need to address the containment zone application <br /> requirements of Water Quality Control Plan for the California Regional Watei Quality <br /> Control Board, Central Valley Region Fourth Edition, (Basin Plan) revised August 2006. <br /> The cost of the LUC alternative must include containment zone requirements. <br /> 5. The cost of the pump and treat alternative presented in the Draft FS is significantly <br /> overestimated. Based on the evidence presented in the Draft Mass Removal Report, <br /> the dieldrin beneath the NWC, whether it is sorbed to particles or not sorbed, is <br /> mobilized by groundwater extraction and will migrate greater than a few feet. The <br /> potential for dieldrin to migrate under dynamic conditions is also supported by the fact <br /> that it is mobile under groundwater injection conditions. Therefore, the number of <br /> extraction wells that would be required to implement the groundwater pump and treat <br /> alternative is overestimated in the Draft FS. This would decrease the cost of the pump <br /> and treat alternative. <br /> If you have any questions, please contact me at (916) 464-4675, or by email at <br /> jbrownell@waterboards.ca.gov. <br /> James R. Brownell, P.G. <br /> ate eEngineering Geologist <br /> cc: Mr. Phillip Ramsey, USEPA Region 9, San Francisco <br /> Mr. Peter MacNicholl, DTSC Region 1, Sacramento <br /> Mr. Harlin Knoll, San Joaquin County Health Department, Stockton <br /> Mr. Rich Howard, TechLaw, Inc., Sacramento <br /> Mr. Brian Renaghan, AFCEE, San Antonio, Texas <br /> Mr. Michael Thomas, URS, Sacramento <br /> Mr. John Anthony, Noblis, Greenwood Village, Colorado <br />