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E°MUHO O.BR°MN Ji,. <br /> 01111i <br /> ...,r°e Yl• MA�*EW ROUeIOUGl <br /> 00 <br /> Water Boards <br /> Central Valley Regional Water Quality Control Board <br /> 7 February 2014 <br /> Mr. Abe Northup <br /> CH2M HILL <br /> 8067 East U Ave <br /> Vicksburg, MI 49097 <br /> REVIEW OF MONITORING WELL DESTRUCTION WORK PLAN AND SOIL SAMPLING <br /> PROPOSAL IN BAGGING PLANT AREA, KOPPEL STOCKTON TERMINAL, 2025 WEST <br /> HAZELTON AVE., STOCKTON, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the January 2014 Monitoring Well Destruction Work Plan(Work Plan) and <br /> the November 2013 2013 Annual Groundwater Monitoring Report(Annual Report) prepared by <br /> CH2M Hill. Koppel Stockton has been conducting pliytoremediation at the Koppel Stockton <br /> Terminal since about 2000. In 2013, Koppel applied supplemental soil amendments to <br /> accelerate phytoremediation treatment at the bagging plant area and requested no further <br /> action on its stormwater pond parcel. In its 8 January 2014 letter responding to the request for <br /> no further action and review of the Annual Report, Central Valley Water Board staff <br /> acknowledged that the stormwater pond parcel appears to meet the soil and groundwater <br /> cleanup objectives. Central Valley Water Board staff requested that Koppel Stockton prepare a <br /> work plan to destroy deep monitoring well KP-4D and shallow monitoring well KP-4 at the <br /> stormwater pond parcel. Furthermore, the remaining deep monitoring well KP-6D is no longer <br /> needed and may also be destroyed. Monitoring well TG-5 will remain on the stormwater pond <br /> parcel because it is downgradient of ongoing remediation at the rest of the site. This letter <br /> concurs with the well destruction work plan and addresses soil sampling at the bagging plant as <br /> proposed in the Annual Report. <br /> Well Destructions. <br /> Nitrate and ammonium concentrations in deep wells KP-4D and KP-6D have been below water <br /> quality objectives (10 mg/L nitrate-nitrogen and 1.5 mg/L ammonium) since 2011. Ammonium <br /> in shallow monitoring well KP-4 has been declining since 2008, and was below the water quality <br /> i objective in 2013. Nitrate in KP-4 has been below the water quality objective since 2001. These <br /> monitoring wells are no longer integral to Koppel Stockton's groundwater monitoring network. <br /> Therefore, it is appropriate to destroy them. <br /> The Work Plan proposes to destroy the three wells by overdrilling and sealing with neat cement <br /> to within three feet of grade. The upper three feet will be backfilled with site soil.The well <br /> destructions will proceed with permits from San Joaquin County Environmental Health <br /> Department. Central Valley Water Board staff concur with the Work Plan as proposed. <br /> KARL E. LONOLEY SCD, P.E.,CHAIR PAMELA C. CREEOON P.E., BCEE, EXECUTIVE OFFICER <br /> 11020 Sun Center CrIVe 0200;Rencho Cor/10Eova,CA 95570 1 www.weterboardo.ca.9ev/centralvailey <br /> ' y„NE°YLLEU MPYLR <br />