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r . Californleegional Water Quality C*-rol Board <br /> Central Valley Region <br /> Katherine Hart, Chair <br /> 11020 Sun Center Drive,#200,Rancho Cordova,California 95670-6114 <br /> Matthew Rodriquez (916)464-3291 - FAX(916)4644645 j1 Edmund G.Brown Jr. <br /> Secretaryfor hup://www.waterbouds.ca.gov/ccntralvalley �c^, Governor <br /> Environmental Protection ` V80 <br /> SAN 9 3 2012 <br /> E/vv/Roty <br /> 20 January 2012 PRRMIrSE,ESITH <br /> Mr. Robert Jackson <br /> Environmental Manager <br /> Crop Production Services, Inc. <br /> 3005 Rocky Mountain Ave. <br /> Loveland, Colorado 80538 <br /> REVIEW OF REMEDIAL ACTION PLAN, CROP PRODUCTION SERVICES STOCKTON <br /> FACILITY, 1905 N. BROADWAY, SAN JOAQUIN COUNTY <br /> Crop Production Services, Inc. (CPS) purchased a retail agricultural distribution facility in <br /> Stockton that had released 1,2,3-trichloropropane and other pollutants into groundwater. In <br /> March 2011, CPS conducted a soil investigation that identified on-site soil source areas that <br /> are suspected of contributing to groundwater pollution. CPS has submitted the 16 December <br /> 2011 Remedial Action Plan (Work Plan), prepared by Rubik Environmental, Inc. that outlines a <br /> path towards remediation. <br /> In the Work Plan, CPS proposes to install monitoring wells to resolve data gaps in areas <br /> where soil source pollutants were identified. CPS also proposes to prepare a treatability study <br /> for evaluating insitu amendments targeting destruction of 1,2,3-trichloropropane, and proposes <br /> to submit a Notice of Intent for application of permitting coverage under the California <br /> Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) <br /> General Order No. R5-2008-0149. <br /> Monitoring Well Work Plan <br /> This work plan also serves as a monitoring well work plan to install additional nested <br /> monitoring wells MW-2A/2B, MW-22A/B, MW-23A/B, MW-24A/B adjacent to soil source <br /> areas, and B-zone well MW-25 adjacent to existing extraction well E-1. Existing monitoring <br /> well MW-2 is proposed to be destroyed. <br /> The wells are proposed to be installed as nested wells within a telescoping conductor casing. <br /> In a 10 January 2012 telephone conversation, Mr. Michael Infurna of San Joaquin County <br /> Environmental Health Department discouraged the use of nested wells in favor of clustered <br /> wells. Nested wells require a minimum of 2 inches of grout between well casings and between <br /> well casings and the nested casing. When the wells need to be destroyed, if they contain any <br /> pollutants, the well contents will need to be removed. This is typically done by over-drilling. In <br /> order to over-drill the nested well casing and its grout, a 15" auger will be the minimum <br /> required diameter. Over-drilling deep wells with this diameter auger is difficult, due to the <br /> strain on the auger. Mr. Infurna strongly recommended installing individual wells in close <br /> California Environmental Protection Agency <br /> 0 Recycled Paper <br />