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Circle River Ranch Flood Risk Reduction Project

Circle River Ranch Flood Risk Reduction Project

Project update

King County, as service provider to the King County Flood Control District, has finished 30% design for the Circle River Ranch Flood Risk Reduction Project. If you would like to review and provide input, please download the 30% design package (PDF, 6.5 MB) and email feedback to Chrys Bertolotto by June 30, 2023. Comments received will be considered during the next step in the design. We look forward to hearing from you.

About the selected alternative

The King County Flood Control District selected a flood risk reduction alternative for the project in winter 2021. The selected alternative will repair the damage to the upstream end of the existing revetment (at approximately 10119 416th Ave SE) through construction of a buried setback revetment, approximately the same length as the damaged area. The buried setback revetment will provide erosion protection to the properties downstream from the repair site, behind the damaged revetment. The selected alternative includes acquiring at-risk homes from willing sellers which will permanently reduce risks by getting people out of harm’s way.

Project area

The Circle River Ranch neighborhood is located along the right bank of the South Fork Snoqualmie River, just downstream from the City of North Bend. The damaged area to be repaired is shown in the image below.

Aerial photo showing the Circle River Ranch project location on the South Fork Snoqualmie River

Overview

Flooding and channel migration associated with the South Fork Snoqualmie River threaten the Circle River Ranch neighborhood. The Circle River Ranch Flood Risk Reduction project will identify and evaluate flood and channel migration risk reduction measures to reduce risks to the neighborhood.

The project was prioritized as a near-term action in the South Fork Snoqualmie River Capital Investment Strategy (CIS). The CIS identified near, medium, and long-term actions to address a range of critical flood and erosion risks along the River. In July 2017, the King County Flood Control District’s (FCD) Executive Committee approved the CIS as policy guidance.

King County initiated work on the Circle River Ranch Flood Risk Reduction project in October 2018. Since then, project staff have collected field data on public property in the neighborhood and have been updating riverbank erosion and flooding data. This project will consider the opportunities and constraints associated with various risk reduction measures, including gravel management, structures to deflect river flows, and bank stabilization. Following an alternative analysis of potential solutions, a preferred risk mitigation strategy will be identified for design development and implementation.

The evaluation of potential solutions to address channel migration and erosion hazards will build upon previously completed work including the Circle River Ranch Geomorphic Hazards and Risks Assessment and Alternatives Analysis (Herrera 2012), and the Technical Memorandum Circle River Ranch Geomorphic Conditions, Hazards and Risks Update (Tetra Tech 2015).

Project goals

The actions identified in the South Fork Snoqualmie River CIS were guided by the four goals established by the King County Flood Control District (FCD)(Resolution FCD2014-21.1).

  1. Reduce risks from flood and channel migration hazards.
  2. Reduce the long-term costs of flood hazard management.
  3. Improve the natural environment through sound and sustainable flood hazard management.
  4. Incorporate stakeholder and community values into the corridor planning process.

Public involvement

The King County Flood Control District encourages the community’s feedback and involvement in this project. King County held two virtual community meetings and concluded an online survey in May 2021 to gather input on preliminary design alternatives. A summary of the public comments that were received is now available. Please visit the Online Open House for a meeting recording with closed captions.

The District will be reaching out to the Circle River Ranch neighborhood residents and stakeholders at key milestones to provide project updates and get feedback on the alternative analysis and selected alternative. Questions and comments are welcome at any time. New information will be available on this webpage as future public involvement efforts are scheduled.

Project timeline 

Milestone Anticipated dates
Alternative analysis begins Fall 2019
Existing conditions analysis complete Summer 2020
Share analysis and get input Winter 2020-Spring 2021
FCD selection of preferred alternative Winter 2021
Share selected alternative Spring 2022
Begin project design 2022 - 2023
Construction 2024

Project sponsor

The project is sponsored by the King County Flood Control District.

Project documents

Project documents are available in Adobe Acrobat format. For help using Acrobat files, please visit our Acrobat Help page.

For more information about the Circle River Ranch Flood Risk Reduction Project, please contact Chrys Bertolotto, Snoqualmie and South Fork Skykomish Basin Coordinator, King County River and Floodplain Management Section.

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