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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, documented existing floodplain processes and habitat conditions in the watershed, and presented them to stakeholders and community members during a virtual community workshop in November 2022. The team also asked for input on the evaluation criteria that will be used to evaluate potential floodplain restoration alternatives and updated these criteria based on feedback received during the workshop.

Currently, the study team is reviewing the seven existing small side channels they identified to determine their potential for enhancement and will eliminate those that do not meet the evaluation criteria. To develop alternatives, the team will apply a hydraulic model to several combinations of these potential flow-paths to predict expected future conditions. They will then apply the evaluation criteria to the two best alternatives and compare them to the no-action alternative.

We will present the results of the analysis and seek input on a feasible alternative concept during our final virtual stakeholder meeting on June 1 from 5:30 to 7:30. To participate in the virtual SR 20 Skagit O’Brian Reach Community Workshop #2, please register using the link at the bottom of this webpage.

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.

The intent of the feasibility study is to explore an integrative and collaborative approach to addressing a recurring highway problem in a river basin with a great deal of conservation interest. The primary objectives of the study include:

  • Engage early with stakeholders and potential future project partners.
  • Understand habitat conditions and floodplain processes in the O’Brian Reach and factors that cause bank erosion and flooding.
  • 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.
  • Select a feasible alternative and develop a project concept with input from stakeholders in the basin.
  • Document the results in a feasibility study report.
This map shows the Skagit O'Brian Reach study area located along SR 20 between Rockport and Marblemount in Skagit County.