Navigate Up
Sign In Section Home Port Home Contact Us

Wetland & Habitat Restoration Projects

The Port of Seattle undertakes fish and wildlife habitat restoration projects to compensate for the ecological impacts of development projects and to support voluntary stewardship actions. To date, we completed the following ecological enhancements that made significant contributions to regional stewardship initiatives: 

• Created and enhanced 177 acres of wetland, including 350,000 new trees and shrubs
• Enhanced two miles of stream habitat
• Restored more than 30 acres of intertidal and saltwater habitat  
More than half of these projects were voluntary and not related to development. 
Got a question or comment? Email us

Third Runway Mitigation 

Miller and Des Moines Creeks

In order to build Sea-Tac’s third runway, in 2006 the port negotiated with the U.S. Army Corps of Engineers and Washington Department of Ecology to permit impacts to 18.37 acres of wetland and to relocate 1,000 feet of stream.

To mitigate for these impacts, we constructed 112 acres of wetland near the airport, enhanced about two miles of stream habitat, and excavated 60-acre feet of floodplain storage capacity. Wetland mitigation began with substantial soil excavation and preparation to create new wetlands and plant about 350,000 native trees and shrubs.

Stream mitigation centered on improving fish habitat with 200 pieces of large woody debris, removal of culverts that blocked fish passage, and stabilization of four eroded portions of stream channel. As part of ongoing maintenance, we add water to the two creeks every summer to ensure adequate water levels for fish.

Watch a short video about the return of coho salmon to Miller Creek.

Green River

Birds near the airport present a hazard to airplanes, so we created and enhanced 65 acres of off-site wetland and wetland buffer adjacent to the Green River in Auburn. The Auburn site includes four ponds where waterfowl can nest, forage for food and find protection from predators.

Aquatic Habitat Restoration - Seaport
Our region's aquatic environment, especially salmon habitat, is one of the Northwest's greatest resources. Around Puget Sound, several wild salmon runs have been protected under the Federal Endangered Species Act. Over 150 years ago, this area was 8.2 square miles of mud flat, marsh, forested wetland and a river channel - an ideal home for fish and wildlife. Protecting, enhancing and, when possible, expanding this remaining habitat is crucial to fish and wildlife survival, especially as our region becomes increasingly urban.
When the Port of Seattle designs and constructs marine facilities; plans are implemented that avoid, minimize, and, when appropriate, compensate for any anticipated effects on aquatic habitat.
As integral parts of major infrastructure projects, the Port of Seattle has:
  • Restored or enhanced over 31 acres of fish and wildlife habitat at 16 sites throughout the Duwamish River, Elliott Bay, Puget Sound, and Lake Washington Ship Canal.
  • Improved light penetration in shallow water areas. These close-to-shore waters are particularly crucial for juvenile salmon, as they allow them to migrate in areas inaccessible to large predators. These young salmon depend on the vegetation in these waters for food and protective cover and these plants need light to grow and thrive. The port has increased light penetration by replacing solid piers with grated structures, removing over water structures and removing or reducing the number of pilings supporting docks. 
  • Removed in-water barriers to migrating juvenile fish including a derelict ferry and sunken marina.
  • Replaced more than 10,000 creosote (petroleum-treated) wooden pilings that contaminated fish habitats with fewer numbers of concrete and steel pilings. New, stronger pilings are installed with greater amounts of spacing, allowing more light to reach these under-pier waters.
  • Cleaned up contaminated sediments. The port continues to lead in cleanup of contaminated sediment in Elliott Bay and the Duwamish Waterway. Dredging in the East Waterway removed more than 100,000 tons of contaminated sediments.
Lower Duwamish River Habitat Restoration Plan (LDRHRP)
In 2009, the Port of Seattle Commission adopted the Lower Duwamish River Habitat Restoration Plan. The plan identifies over 70 acres of habitat restoration and enhancement opportunities on port-owned property on the Lower Duwamish River – from the southern tip of Harbor Island to the turning basin near the south end of Boeing Field. Adoption of the plan was preceded by a robust public involvement process that included shoreline property owners, businesses, Native American tribes, community members and environmental groups. The plan is now being used by the port to guide it’s habitat restoration investments on the Duwamish.
Pier 66 Built with the Environment in Mind
A great example of the port's strategy of incorporating environmental improvements into development projects is Pier 66. When this area was redeveloped as a public use area - complete with restaurants, marina, maritime museum, conference facilities and a cruise ship terminal - concrete pilings replaced creosote-treated wooden ones and the structure was designed to provide more light and migration areas for salmon and other sea life.
Terminal 5 Project Includes Restoration of Aquatic Habitat
Terminal 5 expansion project doubled the cargo terminal area and capacity, which made possible restoration of approximately 1.6 acres of aquatic habitat. This project took place in the upstream portion of the Duwamish Waterway, where habitat important to juvenile salmon was once abundant but had been greatly diminished.

40 acres in 25 years

Creating, improving, and restoring in the Duwamish, Green River, and Elliott Bay watersheds. more

Lower Duwamish River Habitat Restoration Plan 2009
 (10.6MB PDF)

Duwamish tour.JPG
Duwamish River History & Restoration 
(2.32MB PDF)

Seaport Fish and Wildlife Habitat Restoration Projects Map (3 MB PDF)