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Projects
Find information about current and planned future Mouth of Duwamish Wet Weather Facilities projects.
December 2024
Thank you for learning about Mouth of Duwamish Wet Weather Facilities this year!
King County kicked off the planning phase for Mouth of Duwamish Wet Weather Facilities in early 2024. Since then, we have made progress towards identifying a solution that meets regulatory requirements. We have also worked to raise awareness of this new effort.
We expect the planning phase to end in spring 2025. This phase will result in a proposal for facilities to control Mouth of Duwamish CSO outfalls and meet regulatory requirements. After the planning phase, King County will begin the work to advance the proposal with input from regulatory agencies, including the Washington State Department of Ecology. We will also begin environmental review under the State Environmental Policy Act (SEPA).
Read our year-end project update for more information about our progress in 2024 and what to expect in the new year
Stay connected!
As we progress through planning, design, and construction, we will continue to provide opportunities for you to ask questions and share thoughts and concerns. For project updates, join our email list using the link in the “stay informed” section of this webpage or by scanning the QR code below.
Can’t make it to one of our virtual or in-person events? Contact Bibiana Ocheke-Ameh at bibiana.ocheke-ameh@kingcounty.gov or 206-477-5604 with questions or to request a briefing for your organization.
Project description
King County is currently evaluating methods to reduce overflows from 5 combined sewer outfalls (shown on the map below) in accordance with Washington State law and the federal consent decree. These methods may include storage, treatment, or conveyance and will result in a variety of future projects.
During the planning phase, the project team will recommend an approach to control CSOs that considers a number of factors including regulatory, cost, environmental, and community priorities. King County’s regulators will review and approve plans before the projects move into design and construction.
We anticipate planning to end in fall 2025, with design and construction of projects associated with the Mouth of Duwamish Wet Weather Facilities to immediately follow.
King County is seeking to understand the feasible options to control pollution from these outfalls and meet regulatory and environmental requirements.
Community outreach
For information about community outreach, visit the Mouth of Duwamish Wet Weather Facilities public engagement webpage.