The Stillaguamish River is a river in the northwestern region of the U.S. state of

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. It is mainly composed of two forks, the longer North Fork Stillaguamish () and the South Fork Stillaguamish. The two forks join near Arlington. From there the Stillaguamish River proper flows for to

Puget Sound Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected m ...

. The river's watershed drains part of the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

north of

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Course

The Stillaguamish River is formed from the confluence of the North and South Forks, both of which rise in the Cascades. Between the North and South forks there is a portion of the Mount Baker-Snoqualmie National Forest called the Boulder River Wilderness. The North Fork rises as several branches in a remote area of Skagit County near Finney Peak, approximately 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 () originates from the northern slopes of Del Campo Peak and Morning Star Peak in central Snohomish County, south of Darrington, and flows west and northwest by Silverton, Verlot, and Granite Falls. The two forks unite at Arlington in northwestern Snohomish County. The combined stream flows west before it briefly splits again to encircle the town of Silvana. The Stillaguamish bifurcates at its delta to form Florence Island before entering

. Hatt Slough flows southwest and is now the primary distributary of the Stillaguamish waters into Port Susan, having been diverted in the early twentieth century. The Old Stillaguamish River Channel flows northwest towards

Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico ...

and then Stanwood on an 8 mile meandering course. Near the Camano Island bridge this channel again splits, forming Leque Island, with the South Pass flowing into Port Susan and the West Pass emptying into the southern end of Skagit Bay.

Natural history

The Stillaguamish River and its tributaries are known for their

salmon Salmon () is the common name for several commercially important species of euryhaline ray-finned fish from the family Salmonidae, which are native to tributaries of the North Atlantic (genus '' Salmo'') and North Pacific (genus '' Onco ...

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.

Hydrology

The north fork of the Stillaguamish river level is monitored by gauges operated by the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

(USGS), and river levels can vary by as much as . The river level rises and falls very quickly, with the average north fork flood duration of eight hours. Of the five highest north fork flood levels on record, three have occurred since 2009.

History

Variant names for the Stillaguamish River, according to the USGS, include Tuxpam River, Stoh-luk-whahmpsh River, Stillaquamish River, Steilaguamish River, Stalukahamish River, and other similar spellings. The 2014 Oso landslide occurred on the North Fork of the Stillaguamish.

References

External links