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WASTE DISCHARGE REQUIREMENTS ORDER NO. R5-2014-0006 _18- FORWARD INC.AND REPUBLIC SERVICES INC. FORWARD CLASS II LANDFILL SAN JOAQUIN COUNTY 0 72.The Discharger proposes to install an intermediate liner where new landfill modules/cells are constructed over the existing Class III waste disposal area. The interface liner consists of, in ascending order: one-foot of existing soil cover; one-foot of additional foundation soil; 24-inch low permeability soil (minimum permeability of 1 X 10-7 cm/sec) or GCL liner; 60-mil HDPE geomembrane; geocomposite drainage layer; and one-foot protective cover soil layer. 73.The Discharger proposes the following construction quality assurance protocols for liner construction.- a. onstruction:a. Monitor placement of drainage layer gravel with a dedicated CQA technician; b. a liner leak test over the entire base liner to be performed after installation of the gravel drainage layer and the operations layer; and c. during placement of the first layer of waste in a new unit, site personnel will monitor waste placement and will exclude materials that could threaten the liner. 74.The May 2002 (subsequently revised in 2002, 2003, 2007 and 2008) Joint Technical Document includes a stability analysis for the landfill and liner system pursuant to Title 27, section 21750(f)(5). The Discharger based the seismic slope stability analysis on two potential earthquake events, a Maximum Creditable Earthquake (MCE) of M 7.9 on the San Andreas Fault at distance 70 Miles and an MCE of M 6.7 on the Great Valley Fault at distance 21 miles. The slope stability analysis was completed using the program SLOPE/W. The gross stability of the landfill and liner was assessed using the maximum slope height and slope gradient. The final static factor of safety of 1.5 can be obtained for the proposed final cover configuration and no significant seismic-induced permanent displacement is anticipated for the proposed cover design for the design earthquakes. Discharger's stability analysis includes components to demonstrate the integrity of the landfill foundation, final slopes, and containment systems under both static and dynamic conditions throughout the landfill's life including the closure period and post-closure maintenance period. The stability analysis demonstrates that the structural components will withstand the forces of the MCE without failure of the containment systems or environmental controls. 75.The Discharger proposes to construct new Class II surface impoundments as needed to contain and evaporate leachate from solid waste management units. An engineered alternative to the prescriptive liner requirements of Title 27 is proposed for the Class II Surface Impoundments. The engineered alternative consists of from the top down: a. A primary 60-mil-thick High Density Polyethylene (HDPE) geomembrane; b. a geonet drainage layer, as a Leachate Collection and Removal System (LCRS); c. a secondary 60-mil-thick HDPE geomembrane; and d. a GCL in place of the compacted clay liner. ® 76.This Order approves the Discharger's proposed liner system for future modules as described in Finding 6 and requires that the Discharger submit design plans and construction quality