In 2020, WSDOT received a Salmon Recovery Funding Board (SRFB) grant to find a long-term solution that reduces flood and erosion damage to State Route 20 from the Skagit River during floods, and improves native fish habitat within the river and its floodplain.
The study team has 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 solicited input on development of project alternatives and evaluation criteria and are refining the draft evaluation criteria.
Currently, the study team is developing alternatives based on these criteria and will evaluate existing conditions against two potential alternatives using a hydraulic model to predict expected future conditions, and then apply the evaluation criteria.
A second virtual community workshop will be held in spring 2023 to review results of the analysis and solicit input on a preferred alternative concept.
Timeline
January 2022 - December 2023
Status
In progress
Budget
$275,000
Purpose
The SR 20 Skagit River O’Brian Reach Feasibility Study study area is located along SR 20 near Rockport at milepost 101 (near Cascade Farms). The purpose of the study is to identify a project concept that will:
Reduce erosion and flood damage to SR 20 during frequent flood events, which often result in the need for emergency repairs and highway closures.
Improve degraded fish habitat in the Skagit River and its floodplain by enhancing the connectivity of side channels and floodplain habitats to the river during small and medium-sized floods.
The feasibility study is a collaborative and integrative approach to address a recurring problem on a state highway in a large 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 and communicate habitat conditions and floodplain processes in the O’Brian Reach and factors that cause bank erosion and flooding.
Develop several fish-friendly project concepts that reduce the force of high river flows on the highway embankment and improve floodplain connectivity and habitat for native salmon and steelhead.
Select a feasible project concept, with input from stakeholders in the basin.
SR 20 near milepost 101 has experienced frequent embankment erosion and flooding and has required repeated emergency repairs from flood events in the Skagit River. This section of the highway is located below the 10-year flood elevation along a meander of the Skagit River that has been slowly migrating downstream.
The Skagit River has migrated towards SR 20 near milepost 101, causing erosion and the need for frequent bank protection projects. Large rock protects the upstream (upper part of photo) portion of the embankment. The downstream embankment (lower part of photo) is protected by the Skagit dolotimber project – a successful, fish-friendly bank protection project installed in 2015, consisting of large concrete jacks and large wood. Photo credit: Natural Systems Design, December 2021.
For several thousand years, the Skagit River migrated freely across the valley creating an extensive network of sloughs, wetlands, ponds, side channels and other off-channel habitats vital to salmon and other native species. Historic changes to the river altered the natural processes that maintain these floodplain habitats and their connection to the river. The loss of native salmon habitat and impairment of natural processes are major factors in the decline of Chinook, chum, coho and pink salmon, steelhead, bull trout and resident trout in the Skagit River.
Improving salmon and steelhead habitat within Washington’s rivers has become a top priority for public agencies, Tribes and private conservation groups, including in the Skagit River.
In November 2017, a small flood event in the Skagit River eroded the embankment and destroyed the eastbound lane of SR 20, requiring a two-week closure to rebuild the highway and install emergency bank protection. Although this work was necessary, the large rock typically used in these repairs contributes to degraded fish habitat in the Skagit River. WSDOT has conducted similar repairs to this section of SR 20 many times since 2004. Historic damage to this highway is often associated with these smaller, frequent flood events.
In November 2017, a small flood event in the Skagit River scoured and eroded the SR 20 embankment at milepost 101, resulting in a 2-week highway closure to repair the highway.
Large rock along the SR 20 embankment contributes to degradation of fish habitat in the Skagit River. March 2021.
WSDOT’s Chronic Environmental Deficiencies (CED) program has been working on a solution to the erosion and flooding problem. The purpose of the CED Program is to proactively implement long-term, nature-based, fish-friendly solutions at frequent repair sites along WSDOT’s river-adjacent highways. These aim to work with watershed processes that often occur on a large scale.
A large portion of the floodplain of the O’Brian Reach is already dedicated to conservation use and managed by organizations working toward salmon recovery in the basin. This presented an opportunity to collaborate with potential conservation partners on a large-scale approach that addresses both problems, instead of implementing a site-specific solution adjacent to the highway.
Floodplain habitat in the O'Brian reach across the river from SR 20 that could be potentially enhanced. This property is already in conservation use. December 2019.
Maximizing the value of cooperative partnerships:
In cooperation with our partners and potential partners this study will:
Provide information and an engagement process to identify feasible conceptual alternatives to address the scour, flooding, and habitat degradation problems. These may include reconnecting floodplains, reconnecting and restoring side channels, and restoring functional channel patterns.
Evaluate whether reconnecting side channel and floodplain habitats within the O’Brian Reach would distribute river flow across more of its floodplain, and reduce the scouring flows at the highway embankment that contribute to the need for highway closures and emergency bank protection.
Evaluate whether alternatives would diversify rearing habitats by creating shallow stream margins, side channels, and other slow-moving habitats that could benefit juvenile life history phases of almost all species of salmonids.
Engage people and ensure opportunities for input on evaluation criteria, potential alternatives, and selection of a preferred alternative, so that the solution is palatable and can result in future project implementation.
Contribute to reducing flooding of other river-adjacent properties.
Existing side channel within the Skagit River floodplain that could be enhanced to improve fish habitat. February 2020.
View the workshop notes (PDF 355KB) and presentation (PDF 22MB) from the first of two virtual community workshops. Participants in the November 29, 2022 workshop learned about and provided input on:
Skagit O’Brian Reach Study goals, objectives, timeline and location.
Results of initial assessments of existing floodplain processes and habitat conditions in the watershed.
Next steps and the process for selecting a preferred conceptual alternative.
Draft evaluation criteria.
Engagement opportunities.
Additional opportunities to learn more include:
Sign up for Listserv updates: Email outreach@vedaenv.com and include in the subject line “Add me to O’Brian Reach Listserv”.
Schedule group and one-on-one meetings with stakeholders: Email outreach@vedaenv.com to schedule a meeting.
Attend stakeholder meetings (Fall 2022 and Summer 2023) which will provide results of the floodplain study and solicit input prior to developing conceptual design alternatives and choosing a preferred design concept.
January – June 2022
Study planning.
Initial stakeholder outreach.
Data collection.
July – December 2022
Develop and refine the hydraulic model.
Study existing conditions using the hydraulic model.
Stakeholder meeting #1: Present results of existing conditions analysis and solicit input on potential project alternatives.
Stakeholder meeting #1: Present results of existing conditions analysis and solicit input on potential project alternatives and evaluation criteria.
Refine evaluation criteria based on community input.
January – June 2023
Develop practical alternatives based on evaluation criteria, community input and data analysis.
Evaluate two potential alternatives using the hydraulic model and evaluation criteria.
Compare alternatives to existing conditions.
Review and revise modeling results.
Stakeholder meeting #2: Present the alternatives and solicit input on a preferred alternative concept.
July 2023 – December 2023
Incorporate feedback and refine the analysis.
Select recommended project concept.
Prepare draft report.
Stakeholders review the draft report.
Finalize Skagit O’Brian Reach Feasibility Study Report.
January 2022
Study begins.
December 2023
Final study report published.
The SR 20 Skagit O’Brian Reach Feasibility study is sponsored through WSDOT’s Chronic Environmental Deficiencies (CED) program and funded with a salmon recovery grant and contributions from partners in the following amounts:
Funding has not yet been identified for the design or construction of a project.
This study is currently in progress. The SR 20 Skagit CED O’Brian Reach study will identify river processes that contribute to erosion and flooding of SR 20 and recommend a project that reduces flooding of the highway and improves fish habitat within this section of the Skagit River.
The outcome will be a report describing existing conditions, river processes, evaluated project concepts and a recommended project. The report is expected to be available in December 2023.
Natural Systems Design (NSD) is WSDOT’s lead contractor implementing the study, with assistance from Veda Environmental leading the stakeholder engagement and Natural Waters LLC for quality control and quality assurance.
