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P <br /> Imo!' EDMUND G.BROWN JR, <br /> NIS <br /> GOVERNOR <br /> C A 61 l O W M I A <br /> TAL <br /> ^w,®e F pr�y1 �i MATTHEW RODRIQUEZ <br /> i p tl SECRETARY FOR <br /> Water Boards o� 1 !sFwCE ENVIRONMENTAL PROTECTION <br /> g orRr.�1Tl K <br /> Central Valley Regional Water Quality Control Board <br /> 14 December 2018 <br /> Taj M. Bahadori, P.E. <br /> San Joaquin County Department of Public Works <br /> P.O. Box 1810 <br /> Stockton, California 95201 <br /> REQUEST FOR MODIFICATION OF LINER ENGINEERED ALTERNATIVE DESIGN, WASTE <br /> DISCHARGE REQUIREMENTS ORDER R5-2015-0058;FOOTHILL LANDFILL, SAN JOAQUIN <br /> COUNTY <br /> Central Valley Water Board staff reviewed the 8 May 2018 technical report Leachate Collection and <br /> Removal System (LCRS) Engineered Alternative Design Report, Foothill Sanitary Landfill Module 2B <br /> (Liner EAD Report). The report requests approval for modification of the leachate collection and <br /> removal system (LCRS) component of the liner design for Landfill 2, Module 2B and future LF-2 <br /> modules. WDR Construction Specification D.1 specifies the following engineered alternative design <br /> (EAD) for LF-2 module liners (WDR table footnotes excluded): <br /> Component Base Liner Side Slopes <br /> Excavation LF-1/1-17-2 Interface <br /> Operations Layer >_2 feet soil <br /> Filter Fabric Geotextile <br /> 9-inch gravel layer <br /> LCRS Appropriately-sized HDPE Geocomposite <br /> collection piping in drainage <br /> troughs <br /> 60-mil HDPE None <br /> Base Liner <br /> Geosynthetic Clay Liner(GCL) <br /> Foundation Layer >_ 1-foot prepared subgrade <br /> The attached drawing (Attachment 1) shows a cross-section of the existing liner design for <br /> Module 2A and that proposed for Module 2B and future LF-2 modules. The Discharger is <br /> requesting approval of the proposed liner EAD modification per WDR Construction Specification <br /> D.6, which requires a demonstration of the following factors to the satisfaction of the Executive <br /> Officer: <br /> 1. The approved components of the liner/final cover system will not be eliminated; <br /> 2. The engineering properties of the liner/final cover system components will not be <br /> substantially reduced; and <br /> 3. The proposed changes to the liner/cover system must be at least as protective of water <br /> quality as the design prescribed under the WDRs. <br /> KARL E. LONGLEY SCD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br /> 11020 Sun Center Drive#200,Rancho Cordova,CA 95670 1 www.waterboards.ca.gov/centralvalley <br /> Ca RECYCLED PAPER <br />