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Eouuno C.B.mm J.. <br /> tj1�• covmnon <br /> T + <br /> e...,. M.n,Ew Roo.,ou¢ <br /> 0 <br /> Water Boards """ """""'" <br /> Central Valley Regional Water Quality Control Board <br /> 23 July 2013 <br /> CH2M HILL <br /> Attn: Abe Northrup <br /> 8067 East 'U' Avenue <br /> Vicksburg, MI 49097 <br /> CONCURRENCE WITH INTERIM REMEDIAL ACTION WORK PLAN, KOPPEL STOCKTON, <br /> 2025 WEST HAZELTON AVENUE, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff have reviewed the June 2013 Former Bagging Plant Interim Remedial Action Work <br /> Plan (Work Plan), prepared by CH2M Hill for Koppel Stockton. Koppel Stockton is removing <br /> nitrate from soil and shallow groundwater by phytoremediation. While nitrate concentrations in <br /> most groundwater monitoring wells have been steadily declining, monitoring well KP-3 in the <br /> former bagging plant area has shown increasing nitrogen concentration since 2005. To assess <br /> the cause of poor tree health near KP-3, Koppel conducted soil investigations in 2011 and 2012 <br /> which identified acidic soil, aluminum toxicity, and consequent poor root development as <br /> contributing factors. Therefore, Koppel proposes to: 1) remove trees, 2) incorporate agricultural <br /> soil amendments, 3) replant trees. Koppel also proposes to destroy three off-site wells. <br /> Soil Amendment <br /> The Work Plan proposes to apply lime (calcium carbonate) at about 5 tons per acre and gypsum <br /> (calcium sulfate) at about 4 tons per acre over the % acre area in the eastern portion of the <br /> former bagging plant. The amendments will be incorporated to a maximum depth of 6 feet by <br /> deep ripping. Lime and gypsum are standard agricultural soil amendments, and the application <br /> rate is within the range of what is typical to improve tilth, provide alkalinity, and sequester <br /> aluminum. Because these are standard agricultural amendments applied at typical rates for <br /> agricultural purposes, a permit will not be required. <br /> Monitoring Well Destructions <br /> Of the five monitoring wells located off-site on the Port of Stockton property, three have been <br /> covered with road base (KP-7S, KP-713, KP-9S) and could not be located in 2012. Koppel <br /> proposes to locate them by survey techniques, destroy KP-7S and KP-713, along with another <br /> off-site well, KP-8S. These three wells have not contained appreciable amounts of nitrogen and <br /> have not been required to be sampled since 2004. <br /> The wells will be overdrilled and sealed by pumping neat cement through a tremie pipe to within <br /> three feet of surface grade. <br /> KARL E. LONOIEY SCD. P.E..num I PAMELA C. CREEDON P.E.. BCEE.cxccunvc orrmcrn <br /> 11020 Sun C.M.,Drive 0200,R.nIho Cordova,CA 95620 1 www.w.Wb.a,dz,cagovJcanlmwaliey <br /> l0 n uneo risen <br />