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l\' California Regional Water Quality Control Board <br /> a001 - <br /> Central Valley Region <br /> Linda S.Adams Karl E.Longley,ScD,P.E.,Chair Arnold <br /> Secretmyfor Schwarunegger <br /> Environmental Protection 11020 San Center Drive#200,Rancho Cordova,California 95670-611�� Governor <br /> Phone(916)464-3291 •FAX(916)464-4645 �L�1❑❑fq // � a� p <br /> http//wrvw.waterboards.ca.gov/centraly-..-, II`/^ ED <br /> JApl O 4 iGio <br /> ENVIRONp <br /> 30 December 2009 PEQ1 virINr <br /> II 11jV <br /> DESJC, M.BENSON <br /> Defense Distribution Depot San Joaquin <br /> P.O. Box 960001 <br /> Stockton, CA 95296 <br /> DRAFT UST 25 REMEDIAL INVESTIGATION WORK PLAN, DEFENSE DISTRIBUTION <br /> DEPOT SAN JOAQUIN— TRACY, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff has reviewed the October 2009 Draft UST 25 Investigation Work Plan (Work <br /> Plan) received 3 November 2009. Engineering-environmental Management Inc., prepared <br /> the Work Plan on behalf of Defense Logistics Agency Enterprise Support San Joaquin, <br /> California (DLA) for the Defense Distribution Depot Tracy Site (DDJC Site), located in Tracy, <br /> California. The DLA investigation objectives are to delineate the extent of petroleum <br /> hydrocarbons, naphthalene, and 2-methylnapthalene in groundwater, sample newly- <br /> constructed monitoring wells quarterly, and estimate the potential for migration of volatile <br /> organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) to Building 255 <br /> indoor air. <br /> The Work Plan proposes the use of a cone penetrometer test and hydraulic profiling tool <br /> (CPT/HPT) to determine the extent of total petroleum hydrocarbons, VOCs, and SVOCs in <br /> the saturated zone adjacent to Building 255. Also, the Work Plan proposes a Technical <br /> Memorandum presenting results of the CPT/HPT investigation. In addition, the Work Plan <br /> proposes installation of approximately five groundwater monitoring wells screened across the <br /> water table and collection of samples quarterly for four quarters. Finally, the Work Plan <br /> proposes to report the well construction work in an installation report and the sampling <br /> results in the DDJC Site quarterly monitoring reports. <br /> Comments <br /> Central Valley Water Board staff comments are presented below: <br /> 1. Central Valley Water Board staff concurs with the number and placement of the <br /> groundwater monitoring wells proposed in the Work Plan, noting that DLA has modified <br /> the locations from those previously proposed in the October 2009 Final UST Investigation <br /> Report. The well that was formerly proposed inside of Building 255 has been replaced <br /> with two wells proposed next to the north and east sides of the building. Regarding the <br /> well to be installed adjacent to the north side of the former UST location, it should be <br /> California Environmental Protection Agency <br /> ped Recycled Paper <br />