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California Ronal Water Quality Contrr3oardli <br /> -_ ;, <br /> Central Valley Region <br /> Karl E. Longley,ScD,P.E.,Chair •W191 <br /> Linda S.Adams Arnold <br /> Secretaryfor I1@0 Sun Center Drive 4200,Rancho Cordova,California 95670-6114 <br /> Phone(916)464-3291 •FAX(916)464-4645 Schwarzenegger <br /> Environmental http://www.waterboards.ca.gov/centralvalley Governor <br /> Protection <br /> 18 September 2008 �1i-sC�IC SEP ZG08 <br /> U <br /> ,� <br /> i <br /> Mr. Jeff Baker ENVIRONM <br /> Tesoro Companies, Inc. PER��I E`V(tIEAL7H <br /> 3450 South 344 Way, Suite 100 /�-RVICES <br /> Auburn, WA 98001-5931 <br /> D ZONE GROUNDWATER REMEDIAL ALTERNATIVES EVALUATION, STOCKTON <br /> TERMINALS TECHNICAL COMMITTEE, TESORO COMPANIES SITE, PORT OF <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Regional Water Board) staff <br /> reviewed the 5 September 2008 Evaluation of Remedial Alternatives for D Zone Groundwater <br /> (Evaluation). Stantec Consulting Corporation (Stantec) submitted the document on behalf of <br /> the Stockton Terminals Technical Committee (STTC). The Evaluation was prepared to <br /> specifically address groundwater pollution on the Tesoro Companies, Inc. (Tesoro) site <br /> caused by a 1999 discharge of 7,000 gallons of product. Remediation reportedly occurred in <br /> 2001 <br /> The Evaluation was submitted in response to the Regional Water Board's 30 July 2008 letter <br /> which provided comments on Tesoro's 2 July 2008 Addendum to Work Plan for Additional <br /> Monitoring Well Installation. That letter requested Tesoro to sumit by 5 September a Feasibility <br /> Study (FS) evaluating several remedial technologies and selecting one or two for pilot testing <br /> to mitigate D zone pollution. The letter also stated that the FS must contain a strategy for <br /> defining the vertical extent of pollution and that after Regional Water Board staff concurrence, <br /> Tesoro will need to submit a work plan for pilot testing of one or two of the remedial <br /> technologies. The Evaluation fulfills the request for an FS. <br /> Tesoro proposes to install remedial injection well TS/MW-3D at the same time that several <br /> nearby wells are being relocated. TS/MW-3D will be installed near existing TS/MW-2D and the <br /> TS/MW-1 monitoring well cluster, which consists of four wells (TS/MW-1A, TS/MW-1 B, <br /> TS/MW-1 C, and TS/MW-1 D). The total depth of TS/MW-2D is 115 feet below ground surface <br /> (bgs), and it is screened between 110 and 115 feet bgs. <br /> Based on the 1 August 2008 Second Quarter 2008 Site Status, Groundwater Monitoring and <br /> Remedial Summary Report (Second QMR), samples collected from the TS/MW-1 wells cluster <br /> and TS/MW-2D contained the constituents listed in the table below. <br /> Excavation and Soil Aeration Report, 14 January 2002, IT Corporation <br /> California Environmental Protection Agency <br /> cl? Recycled Paper <br />