NV5 provided construction quality assurance (CQA) engineering services on three separate projects involving final cover construction and base liner construction at this landfill over a period of three years.
NV5 provided field testing and construction quality control observation during placement and compaction of low permeable clay layers; deployment of geomembrane and geocomposite layers; placement and compaction of the vegetative soil layer; installation of a storm water drainage and collection system; and installation of landfill gas extraction wells, perimeter monitoring wells, and the gas flare and collection system. Our CQA Monitor provided oversight of field testing and observation, laboratory material testing activities, and report preparation. Following completion of the construction activities, NV5 prepared final construction certification documents.
NV5 also provided CQA services for construction of the Class II Leachate Surface Impoundment base liner system. Our CQA oversight required testing and observation during construction and testing of a low permeability test pad; clearing and stripping of vegetative material, excavating approximately 138,500 cubic yards (cy) of native subsurface material; placement and compaction of a 12-inch thick low permeability soil liner over the excavated ponds and general fill area with a maximum permeability of 1.0E-6 cm/sec; installation of about 324,000 sf of 60-mil thick, high density polyethylene (HDPE) geomembrane; installation of about 162,000 sf of geosynthetic clay liner; installation of about 162,000 sf of leak detection geonet and associated pipelines, gravel, sumps, and pan lysimeter; and preparation of Draft and Final CQA Reports.
During Phase 2, we provided CQA monitoring services for closure improvements of Modules 1, 2, and 3 and during final closure of Modules 1 and 3. NV5’s CQA oversight required testing and observation during clearing, stripping, and grading; construction of two low permeability test pads for evaluation of two different low permeability materials; placement and compaction of foundation soil obtained from an onsite borrow area; placement and compaction of imported low permeable clay soil; installation of 40 mil, double-sided, textured, high density polyethylene (HDPE) geomembrane; installation of geocomposite drainage net on slopes that exceed a slope geometry of 2H:1V feet (horizontal to vertical); placement of vegetative soil layer comprised of 50 percent import clay material and 50 percent onsite soil material; construction of landfill gas extraction system, and perimeter vadose zone monitoring probes; installation of the landfill storm water drainage systems; and preparation of Draft and Final CQA reports.