Fred Hutchinson James Delmage Ross Dixy Lee Ray George W. Bush Hazel Wolf Henry M Jackson Warren G. Magnuson Home
Search Encyclopedia
Advanced Search
Home About Us Contact Us Education Bookstore Tourism Advanced Search
7072 essays now available      
Donation system not supported by Safari     Donate Subscribe


Cyberpedias Cyberpedias
Timeline Essays Timeline Essays
People's Histories People's Histories

Selected Collections
Cities & Towns Cities & Towns
County Thumbnails Counties
Biographies Biographies
Interactive Cybertours Interactive Cybertours
Slide Shows Slideshows
Public Ports Public Ports
Audio & Video Audio & Video

Research Shortcuts

Map Searches
Alphabetical Search
Timeline Date Search
Topic Search


Book of the Fortnight
Audio/Video Enhanced
History Bookshelf
Klondike Gold Rush Database
Duvall Newspaper Index
Wellington Scrapbook

More History

Washington FAQs
Washington Milestones
Honor Rolls
Columbia Basin
Walla Walla
Roads & Rails

Cyberpedia Library

< Browse to Previous Essay | Browse to Next Essay >

Cedar River Watershed (King County) -- Environmental Overview Essay 2486 : Printer-Friendly Format

The Cedar River watershed has been in use as Seattle’s main water supply since 1901. This has resulted in many changes to the land, water, forests, and animal habitats within the 91,400-acre environment.

Locations and Description

The Cedar River watershed, located in the eastern central portion of King County, is nearly 24 miles long, and roughly 10 miles wide. Total acreage of the watershed is approximately 91,400 acres. Mountain crests in the Cascade Range form the eastern boundary of the system, and the Cedar River flows westward through the center.

The lower region of the Cedar River watershed, east of Maple Valley, houses the headworks of the water system. The Landsburg headworks is at the westernmost boundary of the watershed, where the Cedar River continues downstream to Lake Washington, 13 miles to the northwest. Pipelines lead from Landsburg to Seattle.

The upper region of the Cedar River watershed is home to Chester Morse Lake (originally Cedar Lake). The original lake surface was 1,530 feet above sea level, but when the river was dammed in 1900, the elevation was raised to 1,560 feet. Chester Morse Lake is more than four miles long, and is primarily fed from the east by the north and south forks of the Cedar River, and from the south by the Rex River.

Water Flow

Most of the watershed lying below an elevation of 1,600 feet consists of a porous glacial deposit (moraine) that is quite deep. A large amount of mountain rainfall flows into Chester Morse Lake, although many streams flowing from the mountains disappear into the ground. Eventually this underground water forms springs in the moraine and is vented back into the river system. The deep moraine provides a natural filtration system, and the Cedar River watershed is only one of six major drinking-water systems in the country that requires no specially fabricated filtration.

Excess water seeping through the glacial moraine partially vents into the Snoqualmie River watershed to the north. The remainder of the water seeps into the Cedar River and Rattlesnake Lake, located near Cedar Falls. When Rattlesnake Lake rises too high, water is diverted into a drainage ditch leading into the Snoqualmie River to the north.

Terrain and Vegetation

Nearby mountains on the eastern border of the watershed are up to 5,500 feet high. Hills rise sharply from stream valleys below and in extreme elevations consist of cliffs and broken rocks leading to the mountain crests. The mountaintops are of solid rock and contain little or no vegetation.

In 1899, when the City took ownership of most of the watershed, nearly 3,000 acres of timber had already been removed near Landsburg. Logging operations were still active, and several sawmills operated nearby. Before logging, most of the lower vegetation was old growth forest consisting of Douglas Fir and a small amount of spruce and cedar.

Evidence exists that a large fire swept through higher elevations (above 1,600 feet) between the years 1,650 and 1,675. This destroyed almost all of the upper timber then standing, except for about 2,000 acres along the Rex River. By 1900, the upper forest was a little over 250 years old and consisted of Doug-fir and hemlock, with a small amount of cedar, spruce, and fir.

Forestation and Regulation

Between 1900 and 1924, little care was given to the watershed’s forest. Timber removal denuded the hillsides. Nearly 30,000 acres of forest were removed, most of it haphazardly, leading to fire hazards and destruction of second-growth potential. Prior to 1924, attempts at reforestation occurred, but frequent fires, spread in part due to careless logging operations, destroyed almost all replantings. Also, most logging camps and sawmills within the watershed had atrocious sanitary conditions, which added to the environmental destruction.

In 1924, the City hired Dean Winkenwerder of the University College of Forestry to come up with a plan relating to the removal and replanting of local timber. Following Winkenwerder’s report, the City hired a forester on a permanent basis. The first forester was Allen Thompson. Logging continued, but methods of operation, sanitary conditions, and fire precautions were regulated and strengthened. Nevertheless, by the year 2000, less than 17 percent of the old growth forest remains, although a large portion of the watershed is thick with 80-year-old second-growth forest.

In 1962, landowners signed the Cedar River Watershed Cooperative Agreement, which set up a process of land transfers that resulted in Seattle's complete ownership of its watershed lands. This led to further procedures for fire protection and public access control. In 1996, the USDA Forest Service ceded its watershed land to the City, which gave Seattle final and sole ownership of the entire watershed.


Erosion caused by deforestation has led to problems with animal habitat. The watershed is home to 81 species of animals and fish, with fish being the most harmed over the last century. Still, land erosion has had a noticeable effect on the deer, bird, amphibian, and other animal populations within the district.

Only in the latter part of the twentieth century have concerted efforts been made to bolster runs of sockeye, coho, and chinook salmon and rainbow, cutthroat, and steelhead trout. In 1999, the City of Seattle created a 50-year watershed plan that includes a salmon hatchery, spawning channels, salmonid habitats, and fish ladders to improve the fish population.

As the twenty-first century begins, efforts are underway to restore and preserve the natural environment within the City's watershed, without affecting the delivery of potable water to hundreds of thousands of King County inhabitants. Needless to say, this delicate balance of life will continue to be fine-tuned for many years to come.

Mary McWilliams, Seattle Water Department History 1854-1954 (City of Seattle: Dogwood Press, 1955), 177-182; City of Seattle Cedar River Habitat Conservation Plan (; J. Martin McComber “Seattle Unveils Plan to Conserve Cedar Watershed,” The Seattle Times, December 10, 1998, (; Additional information provided by Friends of the Cedar River Watershed (

< Browse to Previous Essay | Browse to Next Essay >

Related Topics: Environment | Washington Rivers |

Licensing: This essay is licensed under a Creative Commons license that encourages reproduction with attribution. Credit should be given to both and to the author, and sources must be included with any reproduction. Click the icon for more info. Please note that this Creative Commons license applies to text only, and not to images. For more information regarding individual photos or images, please contact the source noted in the image credit.
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License

Major Support for Provided By: The State of Washington | Patsy Bullitt Collins | Paul G. Allen Family Foundation | Museum Of History & Industry | 4Culture (King County Lodging Tax Revenue) | City of Seattle | City of Bellevue | City of Tacoma | King County | The Peach Foundation | Microsoft Corporation, Other Public and Private Sponsors and Visitors Like You

This essay made possible by:
Rivers in Time Project:
King County
Seattle Public Utilties
Seattle City Light

Cedar Lake, 1930s

Landsburg intake under construction, 1899
Courtesy Seattle Municipal Archives

Burning pile of refuse, near Camp I, at the west side of Cedar Lake, December 5, 1929
Courtesy Seattle Municipal Archives

Rattlesnake Lake, March 2000
Courtesy History Ink

Dense forest in the Cedar River Watershed, 2000
Photo by Heather MacIntosh

Home About Us Contact Us Education Bookstore Tourism Advanced Search is the first online encyclopedia of local and state history created expressly for the Internet. (SM) is a free public and educational resource produced by History Ink, a 501 (c) (3) tax-exempt corporation.
Contact us by phone at 206.447.8140, by mail at Historylink, 1411 4th Ave. Suite 803, Seattle WA 98101 or email