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s EDMUND G. BROWN JR. 6{ GOVERNOR C A L I R O W N I A MATTHEW RODRIOUEZ SECRETARY FOR Water Boards ENVIRONMENTAL PROTECTION Central Valley Regional Water Quality Control Board - RECEIVED — OCT 23 201 14 October 2015 EWRONMENTALli PERMIT/SERVICES Taj M. Bahadori, P.E. San Joaquin County Department of Public Works P.O. Box 1810 Stockton, California 95201 INTERIM APPROVAL OF MODULE START-UP, MODULE 2-PHASE A; WASTE DISCHARGE REQUIREMENTS ORDER R5-2015-0058;FOOTHILL LANDFILL, SAN JOAQUIN COUNTY Central Valley Water Board staff reviewed the 9 October 2015 interim certification report (Construction Quality Assurance (CQA) Certification, Construction of Area 2A at the Foothill Sanitary Landfill, prepared by Advanced Earth Sciences, Inc.) submitted for construction of Module 2, Phase A at the Foothill Landfill. The Discharger has requested Water Board staff's approval to begin waste discharges to the module based on information in the report substantially documenting construction of the module. A final as-built report with complete documentation of construction of the module will be submitted in November 2015. The design report for the module was approved in a 28 January 2015 letter from Water Board staff(copy enclosed). The interim certification 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 lysimeter, foundation layer, geosynthetic clay liner (GCL) and geomembrane layers, leachate collection and recovery system (LCRS) layer, LCRS sump and operations layers. CQA testing conducted for earthwork construction generally included field compaction testing, soil thickness surveys, and laboratory permeability; while CQA testing for geosynthetic layers generally included conformance, seam, and shear testing. Both single interface and multi-layer (sandwich) shear tests were conducted to identify the critical interface (HDPE geomembrane-GCL) of the liner system and verify parameters used in slope stability analysis. Appropriate testing was also conducted on the LCRS and LCRS sump gravel layers (e.g., particle size, hydraulic conductivity). A test pad was used to demonstrate the suitability of substituting pea gravel for rounded/sub-rounded gravel originally specified for the LCRS, given that the rounded/sub-rounded gravel was not locally available at the time of construction. The particle size for the lower foot of operations soil was also modified (increased from 3/8 inches to one inch) to accommodate a minor degree of clumping of the sandy soil stockpiled onsite. In addition to the above test results, the report includes supporting memoranda and laboratory test reports, liner leak detection test results, GCL and geomembrane panel layouts, construction survey maps, and other CQA results. Other-module construction information, such as KARL E. LONGLEY SCD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, E%EcuT a OFFICER 11020 Sun Canter Drive 4200,Rancho Cordova,CA 95670 t WWW.Waterboard-ca.9 o-centralval ley �g nac,vcco anneP