US Army Corps of Engineers
Seattle District

Skokomish River Basin General Investigation Study

Project Partnership Agreement

The Skokomish River Ecosystem Restoration Project met a major milestone when the Project Partnership Agreement was signed by representatives from the U.S. Army Corps of Engineers, the Skokomish Indian Tribe, Mason County and the Washington Department of Natural Resources.

The Project Partnership Agreement was signed September 17, 2019, representing the next step toward constructing the project and signifying the transition from design phase into the construction phase.  It is a legally binding agreement between the Corps and its non-federal sponsors that serves to define responsibilities, cost-sharing and execution of work.

The project aims to restore a total of 277 acres in the Skokomish River Basin including habitat critical for Endangered Species Act (ESA)-listed Chinook and chum salmon, key food sources for southern resident orca whales.

In addition to Chinook and chum salmon, the project will improve habitat for ESA-listed steelhead and bull trout, and over 100 additional wildlife species known to use the Skokomish River for some part of their life cycles.

The project includes channel realignment near the confluence of the North and South Fork Skokomish River to allow for year-round fish passage, installation of large woody debris and engineered log jams, the reconnection of a historic side channel and wetland restoration at two sites.  When complete, it’s expected to benefit an estimated 40 miles of habitat in the river that is periodically inaccessible to ESA-listed species due to lack of water.

The Skokomish Indian Tribe and Mason County are cost-sharing, non-federal sponsors working with the Corps on the approximately $22.1 million restoration effort. 

The Skokomish River is the largest and most diverse tributary to Hood Canal, a 70-mile long natural fjord-like arm of Puget Sound that supports vital natural resources. The project is a critical element of an integrated restoration effort in the entire Skokomish River Basin and complements restoration efforts being completed by others throughout the watershed.

Construction is scheduled to commence in summer 2020 and is expected to last about two years.

Study Overview

General Investigation Study Purpose

The purpose of the Skokomish River Basin General Investigation (GI) feasibility study is to evaluate significant ecosystem degradation in the Skokomish River Basin; to formulate, evaluate, and screen potential solutions to these problems; and to recommend a series of actions and projects that have a federal interest and are supported by a local entity willing to provide the necessary items of local cooperation. There is a strong, united effort by federal, state, and local agencies as well as the Skokomish Indian Tribe for restoration of the Skokomish River Basin. Mason County and the Skokomish Indian Tribe are the cost-sharing, non-federal sponsors of the feasibility study.

Recommended Plan:

A recommended restoration plan was selected that includes a levee removal, a side channel reconnection, wetland restoration at two sites, and placement of large woody debris. The total area of the proposed sites included in the recommended plan is approximately 277 acres.

Projects included in the recommended plan are:

  • Confluence Levee Removal
  • Upstream Large Woody Debris Installation
  • Wetland Restoration at River Mile 9
  • Wetland Restoration at Grange
  • Side Channel Reconnection

Final Feasibility Report and Environmental Impact Statement

The U.S. Army Corps of Engineers has finalized the Feasibility Report and Environmental Impact Statement for the Skokomish River Basin Ecosystem Restoration Project.  The Chief's Report was signed December 14, 2015.  The Record of Decision was signed on April 18, 2016.

About the Skokomish River

The Skokomish River Basin is located on Hood Canal, a natural fjord-like arm of the Puget Sound and water of national significance. The Skokomish River is the largest source of freshwater to Hood Canal as it flows into Annas Bay and of critical importance in the overall health of Hood Canal. Environmental degradation can be seen throughout the Skokomish River Basin including a loss of natural ecosystem structures, functions, and processes necessary to support critical fish and wildlife habitat. The degradation of riverine and estuarine habitat has resulted in the listing of four anadromous fish species under the Endangered Species Act (ESA) (Chinook salmon, chum salmon, steelhead, and bull trout) that utilize the river as their primary habitat. The impaired ecosystem has adversely affected riverine, wetland and estuarine habitats that are critical to these and other listed species.