Trafton Floodplain Restoration

The Stillaguamish Tribe and Snohomish County are partnering on a large floodplain restoration project along two miles of the North Fork Stillaguamish River at Trafton. The project area is around 250 acres: 176 acres owned by the Tribe and around 70 acres of Trafton Trailhead Park, which is owned by the County.

While the Stillaguamish River supports a great diversity of animal species, much of the historic floodplain habitats of the area were cleared, drained, diked, and armored over the past 100 years. These changes have drastically reduced habitat for all species, especially salmonids and Chinook in particular.

The Tribe intends to restore reach-scale river processes, salmon habitat, and achieve their tribal vision for watershed recovery on the lands they own at Trafton. 

The current pattern of the North Fork Stillaguamish River has potential to threaten the stability of the Whitehorse Trail and bridge adjacent to the restoration area. By partnering with the Tribe on this project the trail can be protected, and an additional 70 acres of floodplain can be restored.

This project also provides an opportunity for the County to partner with the Tribe and act on Executive Somers’ Puget Sound Salmon Safe Pledge.  One of the actions within his pledge is to pursue habitat restoration on County-owned lands.

The design for the Preferred Alternative maximizes new side channel and floodplain habitat on both the tribe and the county's property as well as maximizing the protection of the Whitehorse Trail. This design includes: 
 

• Activating the floodplain: removing rock and levee around the perimeter of the Tribe's property, and reconnecting the river to the project site as completely as possible
• New primary side channels (dark blue) and tertiary side channels (light blue) spread energy across the floodplain. The primary side channel alignment is extended onto the county's property, creating not only additional habitat but altering the energy of the river to better align with the trestle and protect the Whitehorse Trail
• Engineered log jams throughout, improving habitat for juvenile and adult salmonids and reducing flood velocity
• Floodplain roughness berms throughout, reducing flood velocities on site and in the North Fork
• Riparian plantings and weed control across the tribe's property, providing shade to cool water temperatures and to be a future source of wood for future log jams. Both outcomes improve instream habitat for salmonids
• New berm along the Whitehorse Trail, protecting the trail and keeping excavated soil on site
• Construction of a fisher trail near the trestle at the south end of the county's property, allowing for easier access to the river
• Construction of an interpretive trail near the Whitehorse Trail on the county's property, providing a place for trail users to learn about the project and larger salmon recovery efforts