Cedar River - Lake Washington Watershed
The Cedar River - Lake Washington Watershed is the land area in which rainwater drains to Lake Washington and out through the Hiram Chittenden Locks. The Cedar River - Lake Washington watershed includes the Cedar River and its tributaries, May Creek, Coal Creek, Mercer Island, Mercer Slough, Kelsey Creek, Fairweather Creek, Yarrow Creek, Juanita Creek, Forbes Creek, Lyon Creek, McAleer Creek, Thornton Creek, Ravenna Creek and of course, Lake Washington.
The Sammamish Watershed drains into Lake Washington too, and is published on a separate page.; That drainage includes Swamp Creek, North Creek, Bear Creek and Little Bear Creek, Cottage Lake Creek, Evans Creek, Issaquah Creek, Tibbetts Creek and a number of smaller creeks draining to the east and west shores of Lake Sammamish.
Basin Steward Program
Look up watershed experts to get answers to questions and help solve watershed related problems.
Cedar River Council
Public-private community group that promotes the health of the Cedar River Basin, focusing on lower basin issues.
Community service centers
Information about King County's satellite offices including the Black River community center in the Cedar River watershed at Renton. Office address is 900 Oaksdale Ave. S.W., Renton, WA 98055, phone number 206-296-7810. The Covington community service center is located at 27331 172nd Ave. SE, # 116, Covington, WA 98042, phone number 206-296-1387. The Northshore community service center is located at 10808 N.E. 145th St., Bothell, WA 98011, phone number 206-296-9840.
- Cedar River closed: Nine-mile stretch from Maple Valley to Renton
- Cedar River – River Mile 11 (near Cedar Grove Rd)
- Other reported river hazards
Projects in the Cedar River - Lake Washington Watershed
Water and land improvement projects, Cedar River - Lake Washington Watershed
Look up flooding, wastewater treatment and stormwater projects in King County, Washington.
Flooding and hydrology
Cedar River flooding information
Look up real time gage data, flood stage info and learn what it means along the Cedar River.
Cedar River flood level viewer
Interactive map showing flood depths at various flood levels.
Hydrologic gage data map
Look up detailed gaging station data for creeks and rivers in the region.
Surface water management and groundwater
Stormwater runoff pollution and how to reduce it
Tips on how to reduce water pollution from home, yard, car, pets and so forth.
Lake Washington information
This page offers everything we have about the lake, its environment and recreational information.
Henderson/ Martin Luther King combined sewer overflow project
A stormwater storage tunnel project in the Rainier Beach area of South Seattle, designed to keep Lake Washington clean.
Swimming beach data
Find information about levels of bacterial pollution and relative human health risks at swimming beaches on Lake Washington, Lake Sammamish, and other King County lakes.
Stormwater runoff pollution and how to reduce it
Rainstorms rinse the watershed faster when covered by hard surfaces like roofs and roads. Learn how stormwater brings pollution, wastes and sediments into streams, rivers and lakes and how you can keep stormwater clean.
Rivers and streams: ongoing water quality sampling in Lake Washington streams and rivers. Water quality data are available online for:
- Cedar River
- Coal Creek
- Fairweather Creek
- Forbes Creek
- Juanita Creek
- Kelsey Creek
- Lyon Creek
- May Creek
- McAleer Creek
- Thornton Creek
- Yarrow Creek
- Information for creeks draining to Lake Washington from the the Sammamish River are available from the Sammamish Watershed page.
Lakes: statistics and water quality
- Bitter Lake
- Boren Lake
- Lake Desire
- Echo Lake
- Forbes Lake
- Lake Francis
- Green Lake
- Haller Lake
- Lake Kathleen
- Shadow Lake
- Shady Lake
- Spring Lake
- Lake Twelve
- Walsh Lake
- Webster Lake
Lake Weedwatcher Program
Got a small boat? Interested in saving a lake from the horrors of dense weed infestations?
Cedar River - Lake Washington Watershed map
Drainage map displaying streams, lakes, drainage divides, major roads and cities in the area that drains to Lake Washington and out the Hiram M. Chittenden Locks, except for the Sammamish Watershed area. The map is in Acrobat format. File size is 445 Kb.
South King County Groundwater Management Area
Learn about plans to protect the aquifer in the south county area including the Cedar River watershed localities of Renton, Black Diamond, Maple Valley, and areas in between.
Final Adopted May Creek Basin Action Plan
This plan provides regulatory guidance, programs, and projects aimed to reduce the threat of flooding to citizens in the May Creek Basin, to make improvements to effectively handle stormflow while stabilizing stream banks and reducing erosion, to protect and enhance fish and wildlife habitat and water quality in the basin, and to take reasonable steps to prevent existing problems from worsening in the future. May Creek flows into Lake Washington.
Lower Cedar River Basin Planning documents
- Current and Future Conditions Report (13.8 Mb Acrobat pdf), April, 1993
- Current and Future Conditions Summary Report (10 Mb Acrobat pdf), October, 1993
- Lower Cedar River Basin and Nonpoint Pollution Action Plan (13.9 Mb Acrobat pdf), July, 1998
- Lower Cedar River Basin Plan summary
An overview of the issues and recommendations in the Basin Plan
Urbanization of Aquatic Systems: Degradation Thresholds, Stormwater Detection and the Limits of Mitigation (Acrobat pdf, external)
King County study concluding that "approximately 10 percent effective impervious area in a watershed typically yields demonstrable, and probably irreversible, loss of aquatic-system function."
For salmon viewing and fishing access, please refer to the recreation and appreciation section below.
WRIA 8 salmon recovery - Lake Washington, Cedar River, and Sammamish
Multi-jurisdictional site provides news and data about the recovery of threatened salmon species in the Sammamish, Lake Washington, and Cedar River drainage area and provides an overview of the planning process, scientific information, and meeting records.
Story Map: Salmon Recovery in the Lake Washington/Cedar/Sammamish Watershed (WRIA 8)
Map of efforts to restore habitat for Chinook salmon, representing a variety of habitat types within the WRIA 8 administrative area.
Greening your Shoreline
References and recipes for lakeshore property owners on Lake Washington and Lake Sammamish to use to improve shorelines for people and salmon.
- Final WRIA 8 chinook salmon conservation plan
Cedar River, Sammamish, Lake Washington
- Chinook Conservation Plan Implementation Progress Report, 2011
State of the Chinook salmon populations, the watershed, and efforts to implement the WRIA 8 Chinook Conservation Plan during the first five years (2005-2010).
- WRIA 8 Land Cover Change Analysis, 2011 (2.3 Mb Acrobat pdf)
- Known freshwater distribution of salmon and trout
Draft maps showing chinook, coho, cutthroat trout, kokanee, sockeye, and steelhead distribution in the greater Lake Washington watershed (WRIA 8), based on the collective personal knowledge of resource professionals and data gathered from published and unpublished databases.
Salmon Watcher monitoring sites map
See the sites in Sammamish Watershed and consider volunteering to be a Salmon Watcher next fall.
- King County watersheds map
- Lakes in King County, Washington
- Puget Sound marine topics
- King County environment
- Dept. of Natural Resources and Parks
- Water and Land Resources Division
- Wastewater Treatment Division
- Parks and Recreation Division
News and announcements
Sign up for Cedar River news:
Nov. 11, 2017
External article, The News Tribune
Company wants to dig 90,000 tons of coal per year at currently idled King County mine
Cedar River Cleanup (Acrobat pdf)
Saturday, May 20 8 a.m. to 12:30 p.m.
Limpieza del Río Cedar (Acrobat pdf)
Sábado, 20 de mayo de 2017, de 8:00 a. m. a 12:30 p. m.
¡Necesitamos su ayuda para limpiar el Río Cedar!
Dec. 1, 2016
External article, Bothell Reporter
Searching for the little red fish in local streams
Jun. 21, 2016
External article, Seattle Times
Regional council warns 5 King County towns they’re growing too fast
May 26, 2016
External article, KOMO News
Renton to dredge Cedar River in hopes to prevent major flooding