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California legional Water Quality Contr*Board Fes ' <br /> \ <br /> � Central Valley Region <br /> Katherine Hart,Chair <br /> Arnold <br /> Linda S.Adams 11020 Sun Center Drive#200,Rancho Cordova,California 956706114 schwarzenegg <br /> Secretaryfor <br /> Phone(916)464-3291 •FAX(916)464-4645 Governor <br /> bm,onnrenlal - http://www.waterboards.ca.gov/centralvalley <br /> Proleclion <br /> 11 March 2010 <br /> i ' MAR 15 2010 <br /> Mr. Jeff Baker <br /> Tesoro Companies, Inc. �g <br /> 3450 South 344" Way, Suite 100 <br /> Auburn, WA 98001-5931 <br /> FOURTH QUARTER 2009 SITE STATUS, GROUNDWATER MONITORING AND <br /> REMEDIAL SUPAMARYREPORT, STOCKTON TERMINALS TECHNICAL <br /> COMMITTEE FACILITIES, PORT OF STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the 1 February 2010 Fourth Quarter and Annual 2009 Site Status, <br /> Groundwater Monitoring and Remedial Summary Report(Annual Report) submitted on <br /> behalf of the Stockton Terminals Technical Committee (STTC) by Stantec Consulting <br /> Corporation (Stantec). STTC is comprised of three bulk fuel facilities at the Port of <br /> Stockton including British Petroleum (BP, formerly ARCO), Tesoro Petroleum Company <br /> Inc. (Tesoro), and Time Oil Company (TOC). These terminals are collectively referred <br /> to as the Site. <br /> The principal contaminants of concern (CDCs) at the Site include total petroleum <br /> hydrocarbons as gasoline (TPHg), TPH as diesel (TPHd), benzene, toluene, <br /> ethylbenzene, and xylenes (collectively BTEX), tertiary amyl methyl ether(TAME), <br /> methyl tertiary butyl ether (MTBE), and tertiary butyl alcohol (TBA). Methylene blue <br /> active substances (MBAS) also has been observed in groundwater after monitoring for <br /> this constituent began in March 2009 following a November 2008 release of fire <br /> suppression foam from the BP loading rack. <br /> The S -coaducts- ri-onitoring at the Site pursuant to Monitoring and Reporting <br /> Program (MRP) No. R5-2004-0823. Stantec conducted groundwater monitoring for the <br /> fourth quarter of 2009 between 3 and 7 November 2009. Sediments underlying the Site <br /> are subdivided into four progressively deeper hydtostratigraphic units classified as the <br /> A Zone, B Zone, C Zone, and D Zone. During the fourth quarter, depth to groundwater <br /> ranged from about two to 11 feet below ground surface (bgs). Stantec calculated that <br /> groundwater flowed toward the southeast in all the zones at gradients ranging from <br /> 0.001 to 0.004 feet per foot. The historically downward vertical gradients between the <br /> four hydrostratigraphic units were also predominantly downward during the fourth <br /> quarter. <br /> During October 2008, Stantec conducted a site-wide resurvey of groundwater <br /> monitoring wells at STTC. Despite this resurvey, a depression remains in calculated <br /> groundwater elevations in a downgradient groundwater monitoring well at the NuStar <br /> California Environmental Protection Agency <br /> ��Recycled Paper <br />