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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 characterize and assess existing riverine and floodplain conditions in the Skagit River, and explore a floodplain restoration alternative as a potential solution to reduce flood and erosion damage to State Route 20 and improve native fish habitat in the river and its floodplain.

The feasibility study and report were completed in December 2023, and the report is available for viewing and download below.

January 2022 - December 2023


The SR 20 Skagit River O’Brian Reach Feasibility Study area is located along SR 20 near Rockport at milepost 101. This section of SR 20 experiences frequent embankment erosion and flooding and has required repeated emergency repairs following floods in the Skagit River. The purpose of the study was to characterize and assess floodplain connectivity, hydraulic processes, and fish habitat to determine if there is a feasible floodplain restoration action that:

  • 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.
  • Reduces erosion and flood damage to SR 20 during frequent flood events and does not increase risk to adjacent property or infrastructure.
  • Is acceptable to the community and feasible based on other factors, such as cost, sustainability, wildlife, recreation, aesthetics, and opportunities to collaborate.

This technical study engaged potential project partners and the public throughout the study, and the results were documented in a feasibility study report. This was not a project planning study, and the alternatives evaluated will not result in a WSDOT project proposal.

Feasibility study report

The final Skagit O’Brian Feasibility Study Report - Part 1 (PDF 28MB) and the Skagit O’Brian Feasibility Study Report - Part 2 (PDF 26MB) documents the analyses and evaluation used in the study to develop the conceptual alternatives and conceptual design.

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