Debris in the November 2006 flood is swept under the Route 9 Bridge Measured at Monroe, the Snohomish River has an average annual flow of 9,500 ft³/s). In comparison, the Columbia River, Washington's largest river, has an average flow of about 265,000 cubic feet per second (7,500 m3/s).
Snohomish County has developed thie Snohomish Water Basin Salmon Habitat Conservation Plan to protect the endangered Chinook salmon. Information and documents can be found on the county’s website HERE.
There are 4 cities and 1 town along the Snohomish River: Everett, Snohomish, Monroe, Sultan, Gold Bar and Index. Each of these cities are required to help protect the river through their individual Critical Areas Ordinances and Shoreline Master Programs.
Much of the commercially designated farmland is in the shorelines of both the Snohomish and Stillaguamish River basins. To find a win-win-solution for both protection of farmland and restoration of salmon habitat, the County convened a group from both sides of this important issue to try to find solutions. This group, the Sustainable Lands Strategy, has completed Phase 1 of this process, and have agreed to a non-regulatory framework. That documentataion will be available for public review soon. There will be a Phase II of this process TBA.
The Stillaguamish River: The Stillaguamish River is formed from the confluence of the North and South Forks, both of which rise in the Cascades. The North Fork rises as several branches in a remote area of Skagit County near Finney Peak, approximately 10 miles (16 km) north of Darrington. Collecting many tributary creeks, the river flows south, then west through the foothills along the Skagit-Snohomish county line. Tributaries of the North Fork Stillaguamish River include Boulder River and Deer Creek.
The South Fork (30 miles (48 km)) rises near in central Snohomish County, 20 miles (32 km) south of Darrington, and flows west and northwest by Silverton, Verlot, and Granite Falls.
The Stillaguamish River and its tributaries are known for their salmon runs. Eight salmonid species use the streams for spawning, including chinook, coho, chum, pink, and sockeye salmon, steelhead trout, sea-run cutthroat, and bull trout. There are 4 cities along the Stillaguamish River: Stanwood, Arlington, Granite Falls, and Darrington. These cities are responsible for protection of the river through their Critical Areas Ordinance and Shoreline Master Plans.
Snohomish County has several process for protection of the Stillaguamish River. One is the Flood Hazard Management Plan which can be found HERE.
Another is the Stillaguamish Clean Water District (CWD) Advisory Board. That information can be found HERE. All water bodies in Snohomish County must be protected as part of the Clean Water Act from stormwater runoff. As such, the County has adopted regulations through the National Pollutant Discharge Eliminiation System (NPDES). More information about this can be found HERE.