SAMMAMISH RIVER

The 'Sammamish River' (also known as 'Sammamish Slough') flows through north King County, Washington, draining Lake Sammamish into Lake Washington. Along its course, the Sammamish River flows through Redmond, Woodinville, Bothell, and Kenmore.

Contents

Geography

Course Modifications

Recreation

External links

Geography

The Sammamish River basin includes Lake Sammamish, four major tributaries, and several smaller drainages that enter along the length of the river before it discharges to Lake Washington. The total basin drainage area covers approximately 626 km² (242 mi²), including the surface of Lake Sammamish. Big Bear Creek is the largest of the four major tributaries that feed the river followed by Little Bear Creek, North Creek, and Swamp Creek. There is also a significant amount of more diffuse drainage, primarily originating from the hills and valley to the west of the river.

Course Modifications

The Sammamish River of the early 1800s has been extensively modified as a result of various human efforts to use the channel for navigation, to utilize the floodplain for agriculture, and to reduce flooding in the Sammamish River valley and Lake Sammamish. Prior to major hydrologic modifications that began in the early 1900s, the river was wider and deeper and generally flowed more slowly due to a relatively small difference in elevation between Lake Sammamish and Lake Washington. Prior to these modifications, the river was known as Squak Slough and was navigable over its entire length by shallow-draft steamers and was used to float logs and coal barges from Lake Sammamish to Lake Washington.
Although early drainage and navigation improvement efforts likely affected the form and function of the river, the most significant modifications occurred as a result of two largely federal-funded navigation and flood control projects. The first major change occurred as a result of the reduction in the mean level and seasonal elevation range of Lake Washington in 1916 as part of the development of the Lake Washington Ship Canal and Lock system, which officially opened June 16, 1917. This effectively increased the elevation difference between Lake Sammamish and Lake Washington and increased the flow rate of the river.

The second major change resulted from a King County/ACOE channel dredging, straightening project completed in November 1964 that included construction of a weir at the Lake Sammamish outlet. This project practically eliminated flooding in the Sammamish River valley and reduced maximum flood elevations and seasonal water surface elevations in Lake Sammamish. The weir was modified in 1998 to improve passage for anadromous salmon during low flow.

Recreation

The Sammamish River Trail is a paved bicycle and walking trail that runs along the river, from Marymoor Park in Redmond, to Bothell, where it connects to the Burke-Gilman Trail to Seattle.

External links

★ Sammamish River Watershed