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\ EDMUND G.BROWN JR. �S�;PI GOVERNDR CAL16OWNiA MATTHEW RODRIQUEZ Water ars SECRETARY I ENVIRONMENTA-L vROTECTION Central Valley Regional Water Quality Control Board 27 December 2017 JAN 0 2 2018 Taj M. Bahadori, P.E. EtFlQ ER ITfSE� San Joaquin County Department of Public Works CE P.O. Box 1810 Stockton, California 95201 FINAL CONSTRUCTION QUALITY ASSURANCE(CQA) REPORT;MODULE 5B; WASTE DISCHARGE REQUIREMENTS ORDER R5-2010-0016;NORTH COUNTY LANDFILL; SAN JOAQUIN COUNTY Central Valley Water Board staff reviewed the 15 December 2017 Final Construction Quality Assurance (CQA) Report (As-Built CQA Report, Construction of Landfill Area 5B at North County Sanitary Landfill, prepared by Advanced Earth Sciences, Inc.) for construction of Module 5B at the North County Landfill. The project design was approved in a 3 May 2011 letter from Board staff (see Enclosure 1). An interim CQA report requesting approval to operate the module on a temporary basis pending submission of the Final CQA Report was approved in a 6 December 2017 letter from Board staff(see Enclosure 2). The subject Final CQA Report fully documents construction of the module, including project CQA, as required under the construction specifications of the WDRs for long-term operation of the module. The report provides the results of conformance and CQA testing conducted for construction of the module's monitoring and containment system components (e.g., subgrade, pan lysimeters, soil gas collection piping, foundation layer, geosynthetic clay liner, 60 mil HDPE geomembrane liner, geotextile layers, leachate collection and recovery system layer and sump, operations layer, trenches and other project elements). Conformance testing included a review of manufacturer quality control (MQC) data, geosynthetics inventory, and testing of geosynthetic materials (e.g., strength, puncture resistance, weight, thickness, transmissivity, and interface shear strength) to verify conformance with project specifications. Conformance testing was also conducted on project earthworks that required onsite processing. CQA testing included field and laboratory testing of project earthworks (e.g., compaction, thickness, gradation, soil type, permeability) including subgrade, foundation layer, trenches, backfill and leachate collection and recovery system (LCRS) gravel. Geosynthetics testing included non- destructive seam testing (e.g., by air pressure and vacuum box methods) and destructive seam testing for peel and shear strength. CQA testing was also conducted for installation of soil gas collection piping and pan lysimeters beneath the foundation layer. CQA activities also included observation of the installation of each component and leak detection testing of the 60 mil HDPE geomembrane liner before and after placement of the LCRS and operations layers, as described in the interim approval letter (Enclosure 2). The report includes narrative description, tables of CQA test data, as-built drawings, laboratory reports; daily field reports; photographs; geosynthetics inventory and panel layouts; earthwork and piping survey data and maps; CQA procedures, geosynthetic materials inventory; manufacturer's CQA data, and various other CQA documentation. Minor variances from the design KARL E. LONGLEY SOD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, EXE—ITIVE OFFICER 11020 Sun Center Drive#200,Rancho Cordova,CA 95670 1 www.weterboards.ca.gov/centralv611ey g;es Re cveeo rner.