Cedar Hills Regional Landfill (CHRLF) Area 8 Development

King County


CHRLF receives municipal solid waste (MSW) from most municipalities and unincorporated areas of King County except the City of Seattle. The Area 8 Development Project is a 34-acre horizontal expansion that provides capacity for an additional 6 years of MSW. The project also included significant site work to modify environmental control facilities serving the new Area. BHC lead significant elements of the Area 8 Development including overall project direction as well as design of lining systems and leachate and contaminated surface water management facilities.


  • 34-acre MSW landfill horizontal expansion with relocation and processing of refuse from a previously-closed area to make room for environmental control facilities
  • A successful regulatory demonstration that the proposed alternative lining system is equivalent to the prescriptive system under WAC 173-351
  • New contaminated surface water and stormwater detention, treatment, and storage lagoons
  • Leachate pumping facilities and leachate pre-treatment lagoon hydraulic improvements
  • Hydrogeologic and Geotechnical Engineering Reports


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