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J EDMUND G. BROWN JR. 01tIPORMI• P SECRETIARY FOREw DRIOUEZ Water Boards � ENVIRONMENTAL PROTECTION Central Valley Regional Water Quality Control Board REcEwEt) 22 January 2016 JAN 2 7 2016 EAMRONMENTAL H Taj M. Bahadori, P.E. PERMIT/SERWC,,S San Joaquin County Department of Public Works P.O. Box 1810 Stockton, California 95201 FINAL CONSTRUCTION QUALITY ASSURANCE(CQA) REPORT;MODULE 5, PHASE 1; WASTE DISCHARGE REQUIREMENTS ORDER R5-2010-0016; NORTH COUNTY LANDFILL; SAN JOAQUIN COUNTY Central Valley Water Board staff reviewed the October 2015 Final CQA Report (As-Built CQA Report, Construction of Landfill Area 5 at North County Sanitary Landfill, prepared by Advanced Earth Sciences, Inc.) documenting construction of Module 5, Phase 1 at the North County Landfill. The design report for the module, including project plans, specifications, and proposed CQA program, was approved in a 20 November 2014 letter (copy enclosed). The Final CQA Report provides the results of field and laboratory CQA testing conducted during installation of the module's monitoring and containment system components, including subgrade; pan lysimeters; soil gas collection piping; foundation layer; geosynthetic clay liner (GCL) and HDPE geomembrane layers; geotextile layers; leachate collection and recovery system (LCRS) layer and sump; operations layer; trenches and other project elements. Earthwork CQA testing generally included field compaction testing, soil thickness surveys, gradation testing; and laboratory permeability, while CQA testing for geosynthetic layers generally included conformance, seam, and interface shear testing. Appropriate testing was also conducted on the LCRS and LCRS sump gravel layers (e.g., particle size, hydraulic conductivity). CQA activities also included leak detection testing of base, side slope, and LCRS sump geomembrane liners. Leak detection testing was conducted before and after installation of the operations and LCRS layers (i.e., by the Water Puddle and Dipole methods, respectively). No leaks were detected in the geomembrane layers by either method. The report includes a detailed description of the above CQA activities along with project information such as construction specifications; as-built drawings; laboratory test sheets; daily field reports; photographs; geosynthetics layer panel layouts; earthwork and piping survey data and maps; CQA procedures, geosynthetic materials inventory; manufacturer's CQA data, and various other CQA documentation. The following variances from the approved design plans were approved by the project design engineer (CB&I Environmental and Infrastructure, Inc.) and implemented to address issues encountered during project construction: • Subrounded gravel was used in lieu of rounded gravel in the LCRS layer and LCRS sump after it was determined that the approved source did not meet project specifications and that no other source for rounded gravel was locally available. A 12-oz. geotextile cushion layer was KARL E. LONGLEY SCD, P.E., CI+AIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER 11020 Sun Center Drive#200,Rancho Cordova,CA 95670 1 www.waterboard s.ca.gov/centralvai ley Cp RECYc vn