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` California#gional Water Quality Colt Board <br /> Central Valley Region go <br /> Katherine Hart,Chair. <br /> Arnold <br /> Linda S.Adams 11020 Sun Center Drive#200,Rancho Cordova,California 956706114 - Schwarzenegger <br /> Secretaryfor Phone(916)464-3291 •FAX(916)4644645 Governor <br /> Environmental http://www.waterbouds.ca.gov/centralvaliey <br /> Protection <br /> 10 February 2010 ��f�Qn��D <br /> Mr. Carol Campagna FEB 11 26100 . <br /> Shell Oil Products US ENVIRONMENTH <br /> 20945 South Wilmington Avenue PERMIT/SERV�ESfH <br /> Carson, CA 90810 <br /> REVISED REMEDIAL ACTION PLAN, SHELL STOCKTON TERMINAL, 3515 NAVY DRIVE, <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) <br /> staff reviewed the following documents: <br /> • 30 December 2009 Response to CVWB 17 September 2009 Letter(Response) <br /> 19 January 2010 Revised Remedial Action Plan (Revised RAP) <br /> 29 January 2010 Groundwater Monitoring and Remediation 2009 Semiannual Report <br /> Third and Fourth Quarters (Annual Report) <br /> Conestoga-Rovers and Associates (CRA) submitted these reports on behalf of Shell Oil <br /> Products US (Shell) for Shell's Stockton Terminal at 3515 Navy Drive in Stockton (Site). <br /> The Response adequately addresses the concerns stated in our 17 September 2009 letter. <br /> The Revised RAP provides additional details on the remedial strategy proposed in the <br /> 30 October 2009 Air Sparge/Soil Vapor Extraction Pilot Test Report and Feasibility Study <br /> Addendum (Addendum) and responds to comments in our 25 November 2009 letter. <br /> Laboratory analytical results from previous soil investigations showed that the highest <br /> concentrations of total petroleum hydrocarbons as gasoline (TPHg) and TPH as diesel (TPHd) <br /> are about 10 feet below ground surface (bgs). An air sparge/soil vapor extraction (AS/SVE) <br /> pilot test showed that AS and SVE wells could be installed based on 15-foot and 12.8-foot <br /> radii of influence (ROI), respectively. Groundwater pollution at the Site is divided into three <br /> source areas (SAs) designated as SA1, SA2, and SA3. Based on these observations, Figure 3 <br /> in the Revised RAP shows that Shell is proposing to install nine, 16, and three AS wells in <br /> SA-1, SA-2, and SA-3, respectively. AS wells will be screened from 19 to 21 feet bgs. About <br /> five, eight, and two horizontal SVE wells will be installed in SA-1, SA-2, and SA-3, respectively. <br /> Figure 4 shows that Shell proposes to place visqueen on top of the sand pack surrounding the <br /> SVE wells to mitigate potential short-circuiting from the surface. <br /> The number and location of the proposed remediation wells may be modified based on field <br /> conditions and utility survey information. Shell proposes to submit a well installation work plan <br /> after the system design is finalized. The Revised RAP describes the tentative schedule to <br /> install and begin operating the system once Central Valley Water Board staff concurs with the <br /> Revised RAP. Shell states it will require about three months to design the system, four to six <br /> California Environmental Protection Agency <br /> aZa Recycled Paper <br />