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Californi egional Water Quality Con&l Board <br /> a , <br /> Central Valley Region W ° <br /> Katherine Hart, Chair <br /> IFO° <br /> 11020 Sun Center Drive,#200,Rancho Cordova,California 95670-6114 <br /> Matthew Rodriquez (916)464-3291 °FAX(916)4644645 Edmund G.Brown Jr. <br /> Secretary for http://www.waterboards.ca.gov/centralvalley Governor <br /> Environmental Protection <br /> RECEIVED <br /> "`J 6 3 0 2011 <br /> Ali <br /> 25 August 2011 <br /> ENVIRONMENTAL HEALTH <br /> PERMIT/SERVICES <br /> W. Michael Carroll <br /> San Joaquin County Dept. of Public Works <br /> Solid Waste Division <br /> P.O. Box 1810 <br /> Stockton, CA 95201 <br /> REVIEW OF EVALUATION MONITORING PROGRAM WORK PLAN, CORRAL HOLLOW <br /> LANDFILL, SAN JOAQUIN COUNTY <br /> Central Valley Water Board (Board) staff has reviewed the Evaluation Monitoring Program <br /> (EMP) Work Plan submitted as required by the Water Code Section 13267 Order dated 7 July <br /> 2011. The EMP is required to delineate the nature and extent of landfill impacts resulting from <br /> a release of landfill gas. Multiple volatile organic compounds (VOCs) have been detected in <br /> several groundwater monitoring wells (MW-5 and MW-8) adjacent to the northwest corner of <br /> the landfill. Historically, groundwater in the vicinity of these wells has been impacted. <br /> The 13267 Order requires the Discharger to install a minimum of three groundwater monitoring <br /> wells and other borings deemed necessary to define the nature and extent of contamination. <br /> The work plan submitted by the Discharger proposes to install three temporary wells (MW-9 <br /> through MW-11) to meet the requirements of Task 1 of the 13267 Order. The temporary wells <br /> will be drilled to an approximate depth of 100-feet below ground surface (bgs). The temporary <br /> wells will be constructed with 20-feet of 0.020-inch machine slotted well screen and 80-feet of <br /> schedule 80 PVC blank casing. The sand pack will extend a minimum of three feet above the <br /> well screen followed by a five foot thick bentonite transition seal. The transition seal will be <br /> hydrated and allowed to cure before well sampling or development activities begin. A sanitary <br /> seal will not be installed until initial sampling data becomes available and a determination is <br /> made concerning VOC impacts to groundwater. To secure the temporary wells during the <br /> period of determination, the temporary wells will be covered at the surface with a steel plate <br /> and sand bags surrounded by hydrated bentonite chips. <br /> The wells will be pre-developed using a bailer or surging techniques, and then initial <br /> groundwater samples will be collected. According to the work plan, the initial samples will be <br /> analyzed for VOCs only. Once the VOC results are available and reviewed, a determination <br /> will be made whether a permanent well will be constructed. The Discharger will consult with <br /> staff once the VOC results have been reviewed. Staff understands this approach but has <br /> concerns about the length of time the temporary wells will be left in an incomplete condition. <br /> Since the Discharger has not proposed a turn around time for the laboratory reports, staff <br /> California Environmental Protection Agency <br /> Via,Recycled Paper <br />