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SR 20 Skagit O'Brian Reach Feasibility Study

Planning study news

In 2020, WSDOT received a Salmon Recovery Funding Board (SRFB) grant to explore a floodplain restoration alternative as a potential solution to reduce flood and erosion damage to State Route 20 during Skagit River floods and improve native fish habitat in the river and its floodplain.

The study team began their work in January 2022 by documenting existing floodplain processes and habitat conditions in the watershed, which they presented to stakeholders and community members during a virtual community workshop in November 2022. The team also asked for input on the evaluation criteria that would be used to determine if the floodplain restoration alternatives met the three goals of the study:

1. Improves fish habitat.
2. Reduces flood and erosion risk to SR 20 and does not increase risk to adjacent property or infrastructure.
3. Is feasible based on other factors, such as cost, sustainability, aesthetics, etc.

In winter 2023, the study team reviewed the seven existing small flow paths that they had identified to determine their potential for enhancement. Those meeting the evaluation criteria were developed into two alternative concepts. A hydraulic model was applied to them to predict the potential future hydraulic conditions (flow depths and scour) and fish habitat within and near the study reach. The team then applied the evaluation criteria to them and compared them to the no-action alternative.

The study team presented the preliminary results of the analysis and solicited input during Stakeholder Meeting #2 in June 2023. These preliminary results showed that one alternative had a potential significant increase in fish habitat quantity and quality but showed only minimal reductions in flood or erosion risk to SR 20.

The study team is refining and summarizing the analysis and results in a final study and technical report, which will be published in December 2023. Study materials, including meeting notes, evaluation criteria, a summary of the preliminary results, and the final report (when available) are linked at the bottom of this page.

January 2022 - December 2023
In progress


The SR 20 Skagit River O’Brian Reach Feasibility Study area is located along SR 20 near Rockport at milepost 101. The purpose of the study is to assess floodplain connectivity and channel processes to determine if there is a feasible floodplain restoration action that:

  • Reduces erosion and flood damage to SR 20 during frequent flood events, which often result in the need for emergency repairs and highway closures.
  • Improves degraded fish habitat in the Skagit River and its floodplain by enhancing the connectivity of floodplain habitats to the river during small and medium-sized floods.
  • Is acceptable to adjacent landowners and stakeholders.

This technical study will explore one potential collaborative and fish-friendly approach to address a recurring highway problem in a river basin with a great deal of conservation interest. Tasks include:

  1. Engage early with stakeholders and potential future project partners.
  2. Understand habitat conditions and floodplain processes in the O’Brian Reach and factors that cause bank erosion and flooding.
  3. Develop several alternatives that enhance floodplain connectivity, distribute flows more broadly across the floodplain, reduce the force of high river flows on the highway embankment, and improve habitat for native salmon and steelhead.
  4. Select a feasible alternative and develop a project concept with input from stakeholders in the basin.
  5. Document the results in a feasibility study report.

This is not a project planning study and the alternatives evaluated in this study will not directly result in a WSDOT project proposal.

Materials & Information

View the Skagit O'Brian Reach Scope of Work (PDF 1.3MB) to learn more about the study.

View the evaluation criteria (PDF 141KB) that will be used to develop and evaluate potential restoration alternatives.

View the Preliminary Summary of Findings and Alternatives (PDF 6.8MB) that were shared in Stakeholder Workshop #2.

View the Community Workshop #1 workshop notes (PDF 355KB) and presentation slides (PDF 22MB). Participants in the November 2022 workshop learned about the study goals, results of the existing floodplain processes and habitat conditions assessment, and provided input on the evaluation criteria.

View the Stakeholder Workshop #2 workshop notes (PDF 412KB) and presentation slides (PDF 6.8MB). Participants in the June 2023 meeting learned how the team developed and evaluated alternatives, preliminary results of the alternatives analysis, and provided input on the study to inform the basis of design report.

Ask a question about the study or provide input by emailing Jenni.Dykstra@wsdot.wa.gov.

This map shows the Skagit O'Brian Reach study area located along SR 20 between Rockport and Marblemount in Skagit County.