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3-10 hydroseeding are Best Management Practices (BMP's), as recommended by California Stormwater Quality Association (CASQA). Work performed for the Partial Final Closure is subject to the requirements of the National Pollutant Discharge Elimination System (NPDES) General Permit for Stormwater Discharges Associated with Industrial Activities Order No. 97- O3-DWQ (NPDES No. CASOOOOOI). The NPDES Construction General Permit for Stormwater Discharges Associated with Construction and Land Disturbance Activities Order No. 2009- 0009-DWQ (NPDES No. CASOOOOO2), as modified January 8, 2009 is hereinafter referred to as the "Current Order". The Erosion Control Plan (Figure 5) was prepared utilizing BMP's consistent with the Current Order. The landfill surface will be vegetated with native grasses. The vegetation will protect the upper soil layer and minimize erosion through the vegetation root masses. Table 1 presents the seed mix. Additional erosion control measures will be utilized including a silt fence at the toe of slope, wattles (fiber rolls), and silt fences at the inlets as shown on Figure 5 and detailed on Figure 10. 3.7 Landfill Gas Control The purpose of the landfill gas recovery and monitoring system during closure and post- closure is to protect public health and the environment. The FL gas control and monitoring system will be installed and operated in accordance with 27 CCR, Section 20920 and 40 CFR, Subpart WWW. The primary landfill gas extraction system in the Stage 1B closure area consists of 24 vertical gas extraction wells and a landfill gas flare station. This system was installed in 2001 in the northern portion of the FL. These wells were installed below an intermediate soil liner on the top deck of the landfill and are connected to a perimeter gas header system along the northern and western boundary of the landfill. The well laterals are grouped together and routed to well manifolds around the perimeter. These wells will be utilized to control landfill gas emissions in the Stage 1B partial closure area. In order to integrate the gas control system in the Stage 1B partial closure area with the final cover, the following procedures are proposed for closure construction. Prior to placement of the final cover, the header system will be removed as allowed/dictated in the sites current Permit-to-Operate. The gas header, compressed air, and condensate conveyance lines will be re-installed and made operational after final cover is placed. Any affected wells will be disconnected prior to removal of the header. Headers will be re- installed if the integrity of the pipe remains intact and if it can be adjusted to a positive grade. Otherwise, the pipelines will be replaced. The main header system will remain on- line during the entire construction period. All vertical gas collection wells in place in the Stage 1B partial closure area will be protected during the placement of the final cover since control of landfill gas will continue during cover construction. The top of the vertical wells or well laterals will be extended through the final cover and then reconnected to the perimeter header system line as before. Any damaged or non-functional vertical wells or laterals will be abandoned and new replacements installed to provide gas extraction coverage. Final cover material will be placed and compacted by hand around the wells or vaults to protect against damage by earthmoving equipment. In order to keep the gas system operational during closure, temporary jumpers will be installed outside the closure area to maintain vacuum to the field. Forward Landfill Stage 1B Partial Final Closure/Post-Closure Maintenance Plan-June 2011 SWT Engineering z:\projects\allied waste\forward\11-1014 partial fnl clsr pin\partial final closure plan document\text\sec 3.doc