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California Regional Water Quality Control Board <br /> ( \- Central Valley Region . I <br /> vKarl E. Longley, ScD,P.E.,Chair f <br /> Linda S.Adams Arnold <br /> Secretaryjor 11020 Sun Center Drive#200,Rancho Cordova,California 95670-6114 Schwarzenegger <br /> Environmental Phone(916)464-3291 •FAX(916)464-4645 Governor <br /> Protection http:,'(7�;<ypFas�9ardGe go�D Ivalley <br /> 27 May 2009 <br /> MAY 2 8 2009 <br /> ENVIRONMENT HEALTH <br /> Ms. Vicki Goodenow PERMIi-SE-�I'!CES <br /> NuStar Energy L.P. <br /> 2330 North Loop 1604 West <br /> San Antonio, TX 78278 <br /> GROUNDWATER MONITORING REPORT FIRST QUARTER 2009, NuSTAR TERMINALS <br /> STOCKTON FACILITY, 2941 NAW DRIVE, STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) <br /> staff reviewed the 30 April 2009 Groundwater Monitoring Report, First Quarter 2009 (First <br /> QMR) submitted by Ash Creek Associates, Inc. (Ash Creek) on behalf of NuStar Terminals <br /> Operating Partnership L.P. (NuStar) for the NuStar Terminals Stockton Facility located at <br /> 2941 Navy Drive in Stockton (Site). Groundwater monitoring at the Site is conducted pursuant <br /> to Monitoring and Reporting Program (MRP) No. R5-2007-0818. <br /> NuStar and its predecessor have conducted monitoring at the Site since 1992. In 2002, <br /> gasoline releases occurred from aboveground storage tanks (AGTs) G 3301, G 3302, and <br /> D 1503.The principal contaminants of concern (COCs) include total petroleum hydrocarbons <br /> as gasoline (TPHg), TPH as diesel (TPHd), benzene, toluene, ethylbenzene, and xylenes <br /> (collectively BTEX), tertiary amyl methyl ether (TAME), methyl tertiary butyl ether (MTBE), <br /> tertiary butyl alcohol (TBA), and di-isopropyl ether (DIPS). <br /> Groundwater bearing strata underlying the Site have been subdivided into four progressively <br /> deeper units designated zones A through D by NuStar's predecessors and other responsible <br /> parties at neighboring sites. Based on an investigation NuStar conducted during the Fall of <br /> 2008, however, NuStar has proposed to rename some of its B-zone wells to C-zone wells. <br /> During the first quarter of 2009, depth to groundwater ranged from about three to 11 feet <br /> below ground surface (bgs). Horizontal gradients were calculated to range from 0.001 feet per <br /> foot (ft/ft) to 0.003 ft/ft within each zone. Groundwater flow directions varied from east- <br /> northeast in the shallow (A and B) zones to south-southeast in the deep (C and D) zones. <br /> Downward vertical gradients prevailed between all the water bearing zones. The maximum <br /> downward gradient was calculated for the PS/WC-3S and PS/WC-3M well pair at -0.071 ft/ft. <br /> Downward vertical gradients were predominant between all water bearing units in previous <br /> quarters. <br /> One source area monitoring well, PS/MW-14, has historically contained separate phase <br /> hydrocarbons (SPH), so it was not usually sampled until August 2005, when SPH was no <br /> longer observed. During the first quarter of 2009, PS/P-12 contained the highest concentration <br /> California Environmental Protection Agency <br /> 0 Recycled Paper <br />