COMPLIANCE INFO_FINAL WMU FU-23 DESIGN RPT & CONCURRENCE LTRS

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WMU FINAL WMU FU-23 DESIGN REPORT 2-18-23 5-2 using techniques and materials like those used in constructing the test pad for the field permeability test. Laboratory hydraulic conductivity, particle size analyses, compaction, Atterberg limits, and field density and water content testing will be performed on the clay liner during construction as part of the construction quality assurance (CQA) program. The CQA Manual is included in Appendix D. After constructing the clay liner, the surface of the clay will be protected from desiccation cracks by keeping the surface moist. Immediately prior to geomembrane deployment, the surface of the clay will be prepared by rolling with a smooth drum roller. The entire base of WMU FU-23 will be covered by a 60-mil, double-sided, textured HDPE geomembrane liner. Terminations and future connection edges of the geomembrane will be placed under temporary berms to hold the liner secure during construction and filling. Along future connection edges, the geomembrane edges will be protected by geotextile, plywood sheets, and buried under earth berms. 5.1.2 Geosynthetic Clay Liner The GCL will be placed on the excavation slopes by deploying GCL panels and overlapping panel seams and heat welding. The GCL panels will be anchored in the same trench as the HDPE geomembrane and GDN on the western WMU limit and on the north facing slope of the eastern ridge. Manufacturer-recommended procedures for proper installation of the GCL are included in the Specifications. Inspection and testing of the GCL material and installation are described in the CQA Manual, included in Appendix D. The GCL will be covered with a 60-mil thick, single-sided, textured HDPE geomembrane (textured side against GCL) placed concurrently with GCL deployment. By covering all deployed GCL with HDPE geomembrane, the GCL will be effectively protected from possible moisture damage. However, if the GCL becomes saturated during construction, it will be removed and replaced in accordance with the Specifications (Appendix C). The termination edge of the GCL and geomembrane will be placed in perimeter anchor trenches. 5.1.3 HDPE Geomembrane The 60-mil HDPE geomembrane will be installed in accordance with the Specifications (Appendix C). Extensive CQA will be performed on the geomembrane to identify and repair defects. Tests will be performed on both the geomembrane and on the field-constructed seams. A leak location test will be performed on the geomembrane following installation of the geomembrane itself and following placement of the protective operations layer. CQA inspection and testing procedures are defined in the Specifications (Appendix C) and in the CQA Manual (Appendix D). 5.2 Leachate Collection and Removal System (LCRS) Design calculations were performed to establish that the WMU FU-23 LCRS would meet the Title 27 requirements that the LCRS be designed, constructed, maintained, and operated to collect and remove twice the maximum anticipated daily volume of leachate from the disposal unit. To comply with site WDRs and Title 27 requirements, the 1,000-year, 24-hour storm was used in estimating leachate volumes. Calculations were based on a granular drainage layer hydraulic conductivity of 0.1 cm/sec.