Smith Island / Union Slough Restoration

Map this project on the interactive project overview story map.


The project location is on the Smith Island south of 12th Street NE along Union Slough.


The joint City of Everett and Corps of Engineers project restored riverine and tidal influence to 93 acres of intertidal riverine habitat. The project is divided into 35 acres as part of the cost-shared Federal Section 1135 project, and 58 acres as a mitigation project of the City of Everett. The project is designed to restore intertidal salmon rearing habitat that historically existed along Union Slough. The City of Everett mitigation site was restored in advance of impacts to fresh water wetlands expected from dike improvements and treatment plant expansion.

A new dike was constructed along the North, West, and South perimeter of the restoration site in 2003 and 2004. Additionally internal linear ditches were filled within the restoration area and "low flow" fish channels were excavated to prevent fish stranding in between tide cycles.

In 2007, three 180-foot breaches were excavated in the Union Slough dike allowing tidal water to enter the site. A pedestrian trail is open around the perimeter of the site on the newly constructed dike.

Monitoring of the site includes:
  • Benthic invertebrates
  • Fish use
  • Hydrology
  • Soil
  • Vegetation
  • Water quality
  • Wildlife


Paving of the dike top trail between 4th Street and 12th Street East of the treatment ponds will be done at a later date with limited closures lasting a few days. The roads and pedestrian trails are open.