Cedar Hills Regional Landfill (CHRLF) Area 7 Staged Closure

King County


CHRLF receives municipal solid waste (MSW) from most municipalities and unincorporated areas of King County except the City of Seattle. The Area 7 Staged Closure is a 64-acre MSW landfill closure constructed in 5 Stages. Each stage was a separate design and bid package to close as much of the area as feasible each year. The project also included significant site work to modify environmental control facilities (Landfill Gas(LFG), stormwater and contaminated stormwater, and leachate) serving the new Area. The project included several updates to the Area 7 Plan of Operations. It also included significant collaboration with the Area 8 Development design team.


  • 64-acre MSW landfill Closure constructed in 5 stages
  • Final MSW landfill closure sections compliant with Subtitle D requirements
  • Design of both a 20-year and 8-year design life interim cover sections for slopes that will be covered subsequently by more refuse
  • Design of LFG, Stormwater, and Leachate control facilities
  • Four updates to the Area 7 Plan of Operation
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