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{& EDMUND G. BROWN JR. <br /> GOVERNOR <br /> t�o� <br /> C AL/► 11M1 <br /> D • MATTHEW ORIOUE2 <br /> CRETARV FOR <br /> WaterBoards ENVIRONMENTAL PROTECTION <br /> Central Valley Regional Water Quality Control Board RECEIVE <br /> 21 January 2016 JAN <br /> 2721 <br /> Taj M. Bahadori, P.E. E IRONMENTAL HEALTH <br /> PERMIT/SERVICES <br /> San Joaquin County Department of <br /> Public Works (DPW) <br /> P.O. Box 1810 <br /> Stockton, California 95201 <br /> APPROVAL OF CONSTRUCTION QUALITY ASSURANCE(CQA) REPORT FOR MODULE 5 <br /> REPAIRS; WASTE DISCHARGE REQUIREMENTS ORDER R5-2090-0096;NORTH COUNTY <br /> LANDFILL, SAN JOAQUIN COUNTY <br /> Central Valley Water Board staff reviewed the 20 November 2015 report CQA Repair Report for <br /> Area 5 Damage Repair Work, North County Sanitary Landfill (Repairs Report), prepared by <br /> Advanced Earth Sciences, Inc.. The report documents repairs to a small portion of Module 5's <br /> waste containment system damaged during dozer operations in mid-October 2015. The incident <br /> occurred shortly after interim start-up of the module (as approved in a 3 September 2015 Water <br /> Board staff letter, Enclosure 1) pending submission and approval of final as-built documents for the <br /> module. The subject report documents implementation of the repairs to the module, including a <br /> description of the work, the results of field and laboratory CQA testing, daily logs, photographs, <br /> survey data and other relevant information. <br /> The area damaged, approximately 15-foot square, was located in the southwest corner of the <br /> module about 85 feet upgradient of the module's LCRS sump (Enclosure 2). The damage included <br /> breach of the two-foot thick operations layer and tearing of the underlying geotextile filter fabric, <br /> which resulted in fouling the LCRS gravel during a rainstorm. No damage to the underlying <br /> geotextile cushion layer and the 60-mil HDPE geomembrane was noted. <br /> On 26 October 2015, Water Board staff approved a 20 October 2015 work plan (North County <br /> Landfill Area 5 Damage Repair Work Plan, prepared by San Joaquin County DPW) describing the <br /> proposed repairs. All repair work was conducted in accordance with this work plan and the <br /> originally-approved project specifications and CQA. All repairs were performed by the original <br /> project contractors (i.e., Ford Construction, D&E Construction and CQA contractor Advanced Earth <br /> Sciences, Inc.).The investigation/repair work included: <br /> • Removal of the two-foot operations soil layer in the damaged area, the torn section of <br /> geotextile filter fabric, and the fouled LCRS gravel from the damaged area; <br /> • Checking the underlying LCRS cushion and HDPE geomembrane layers for damage; <br /> • Gradation testing and placement of new LCRS gravel; <br /> • Placement and heat bonding of a new (larger) section of geotextile filter fabric over and <br /> overlapping the damaged area; and <br /> • Screening and placement of new operations soil over the damaged area. <br /> In addition, three test pits installed at Water Board staff's request prior to initiation of repairs <br /> verified that the thickness of the operations layer met project specifications. <br /> KARL E. LONGLEY SCD, P.E.,CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br /> 11020 Sun Center Drive 4200,Rancho Cordova,CA 95670 1 www.Waterboarda_ca.gOV/CentralValley <br /> �y RecvcEo PAPeR <br /> 1 <br />