Atkinson's Fish Passage Projects Promote Environmental Sustainability

September 28, 2023


Several decades ago, large pipes called culverts were the standard on construction projects designed to enable water flow beneath roadways in Washington State. Over time, they have become a barrier to fish passage due to changes in the landscape and stream flow caused by development, logging, and fires. Culverts and other fish barriers disrupt natural migration patterns and endanger fish populations and the ecosystems they support. 

Today, Atkinson is helping the Washington State Department of Transportation (WSDOT) eliminate this disruption by reconnecting streams through the agency’s comprehensive Fish Passage Program, which fosters healthy waterway ecosystems by correcting barriers that keep fish and other aquatic species from moving freely to feed, migrate, and reproduce. Construction efforts also support federal injunction requirements to remove nearly 800 barriers to salmon and steelhead in order to open 90% of blocked habitat by 2030.


The project team uses block nets to prevent movement of fish into the work area.

Most recently, WSDOT selected Atkinson to deliver two of its latest fish passage projects: the I-90, SR 161, SR 202, and SR 203 project in King County, Washington, and the SR 20/ Olson Creek and Unnamed Tributary to Skagit River project in Skagit County, Washington.

At the I-90, SR 161, SR 202, and SR 203 project, Atkinson and design partner Jacobs Engineering Group will remove nine culverts and replace them with water-crossing structures that allow fish to pass and are more resilient to landscape changes. The scope also includes associated stream restoration work. Design is underway, and substantial completion is slated for December 2026.

At the SR 20/Olson Creek and Unnamed Tributary to Skagit River project, Atkinson is replacing two existing fish barrier culverts with fish-passable structures, restoring stream crossings to ensure they are resilient to erosion, providing high-quality floodplain and wetland habitats, and minimizing flood risks to roadways and other public infrastructure. Completion is slated for December 2024.

Meanwhile, fish passage barrier removal is underway at the SR 3 Chico Creek project, which WSDOT awarded Atkinson in 2020. The team is constructing two single-span bridges to eliminate five fish passage barriers in the SR 3 Chico Creek watershed. Both bridges will be constructed with cast-in-place, post-tensioned concrete, eliminating the need for culverts. The project’s design restores the waterway to its more natural condition and promotes wetlands expansion by allowing Chico Creek and its tributaries to flow unimpeded by piers in the water. The project is scheduled for completion in 2026.

In addition to these ongoing projects, Atkinson has completed three other jobs to improve fish passage in Washington State. Through the Fish Passage Program projects and their dedication to sustainable infrastructure development, Atkinson plays a vital role in preserving Washington State’s natural heritage for generations.