Hood Canal Bridge Assessment

How can we protect fish at the Hood Canal Bridge?

Long Live the Kings, in partnership with the Hood Canal Coordinating Council, Tribes, and state and federal agencies, is working to address high steelhead mortality at this floating bridge.

A Bridge Over Troubled Water

Researchers have discovered that the floating Hood Canal Bridge, a vital transportation link between the Olympic and Kitsap Peninsulas, delays the migration of young salmon and steelhead and allows seals to eat them before they can make it out to the ocean.

The Hood Canal Bridge spans the northern outlet of Hood Canal, connecting the Olympic and Kitsap peninsulas. As a floating bridge, its pontoons span 83% of the width of Hood Canal and extend 15 feet down from the water surface.

These pontoons act like a barrier to juvenile steelhead trout, leaving them trapped and vulnerable to predators. Tracking data from Phase 1 of the project indicated that up to 50% of juvenile steelhead that make it to the bridge do not survive past it. Furthermore, certain portions of the bridge appear to collect plankton, encouraging hungry Chinook, chum and forage fish to linger at the bridge, which could increase their susceptibility to predation.

The bridge also impacts temperature, salinity, and currents for miles to either side. This dual threat to fish and their ecosystem may be limiting the effectiveness of millions of dollars already spent recovering steelhead, salmon, and their habitat in Hood Canal.

One Problem, Multiple Fixes

We are working with engineers and experts to develop mitigation strategies that could help fish survive at the Hood Canal Bridge. Some of these strategies include:

Fish Guidance Structures

Two fish guidance structures have been designed and built to help migrating fish navigate around the bridge.

 

Predator Deterrents

Acoustic Startle Devices are being used as an experimental way to keep seals away from the bridge without causing any harm to them or other organisms.

New Bridge Designs

We will be working with engineers to create conceptual designs for a new bridge that could better accommodate the needs of local people and fish.

Request for Qualifications for Services

Related to a Bridge Conceptual Design for the Hood Canal Bridge Ecosystem Impact Assessment

Long Live the Kings, in partnership with the Port Gamble S’Klallam Tribe, is seeking a consultant for design and engineering services from a qualified firm to complete a conceptual design (<10% design completion) that incorporates considerations for fish passage and community needs. The services will inform the broader Hood Canal Bridge Ecosystem Impact Assessment, a multi-faceted initiative addressing the ecological and community impacts of the current bridge and potential redesign. One firm, or team of firms, will be selected for the project. The contract’s total value is estimated to be $300,000. MWBEs are encouraged to apply. Responses are due no later than June 19, 2025 at 5 pm. Interested? Find more information and how to submit your RFQ here.

 

NOTE: A previous RFQ (“Bridge Conceptual Design for the Hood Canal Bridge Ecosystem Impact Assessment”) was released on January 14, 2025. Due to changed circumstances, we are now releasing this new RFQ with only the bridge conceptual design component of the original RFQ.

Project Impact

7

Partnering Agencies

$2.4M

Invested To-Date

4

Steelhead Stocks Affected

Related Resources

Phase 1 Summary Report

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Assessment Plan

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Phase 1 Assessment

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Project Fact Sheet

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NOAA Steelhead Survival Paper

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Bridge's Impact on Steelhead

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