By Steven Schauer, Deputy Executive Director

The fourth Sunday of every September is World Rivers Day, a day to celebrate the world’s waterways. Originating in 2005, World Rivers Day highlights the importance of our rivers, increasing public awareness to inspire the stewardship needed to protect and preserve all rivers around the world. This year, the King County Flood Control District is encouraging you to honor not only the rivers of the world, but also the rivers of King County on this annual day of recognition.

The Rivers of King County

King County is home to several river watersheds that carry water flows from the Cascade Mountains to Puget Sound. The rivers that make up these watersheds pass through forested, agricultural, and highly urbanized areas. This Sunday, September 27, is the special day set aside to honor and protect local rivers like the Cedar, Green & Duwamish, Sammamish, Snoqualmie, South Fork Skykomish, and White. All these rivers are essential lifelines that shape our communities, nourish ecosystems, and support salmon and other wildlife.

Cedar River

Flows from various creeks in the Cascade foothills form the Chester Morse Lake and Masonry Pool, behind the Masonry Dam (aka Cedar River Dam), which was constructed in 1914. Its upper watershed is protected and managed to provide drinking water to more than a million residents in the greater Seattle area. The dam is still operated by the City of Seattle, providing hydroelectric power to the city. Today, the Cedar River begins below the dam, flowing from the Cascades into Lake Washington in the city of Renton. More than 60,000 people live in and around the Cedar River in the communities of Maple Valley, Ravensdale, and Renton.

At Landsburg, about 18% of the river’s flow is diverted for Seattle’s drinking water. The remaining water continues its journey to Lake Washington and eventually the Puget Sound. This watershed supports important salmon recovery efforts (WRIA 8), flood risk reduction infrastructure, water quality monitoring, and community watershed stewardship.

Green & Duwamish Rivers

The Green River begins in far southeast King County, near Blowout Mountain deep in the Cascade Mountain Range. Traveling through the Cascades, gathering flows from numerous creeks and tributaries, the Green River fills the Howard A. Hanson Reservoir. Beyond the Howard A. Hanson Dam, which is operated by the U.S. Army Corps of Engineers, the watershed features extensive flood risk reduction infrastructure, water quality sampling sites, salmon recovery efforts (WRIA 9), pollution remediation efforts (including Superfund cleanup), and recreation along the Green River Trail and other natural areas.

The Green River flows through parts of Auburn, Kent, Renton, SeaTac, Tukwila, and unincorporated King County. The river is home to a diverse community of nearly 30,000 residents and serves as a major economic engine for Washington, contributing one-eighth of Washington State’s Gross Domestic Product. The Green River also supports valuable farmland, life-saving medical facilities, cherished parks, vibrant community centers, natural habitats crucial to salmon populations, and key transportation routes connecting people and goods.

In the City of Tukwila, the Green River flows into the Duwamish River, which in turn flows through the City of Seattle, ending in the Puget Sound at Elliott Bay. The Duwamish River is Seattle’s only river. It flows past the South Seattle neighborhoods of Georgetown and South Park, and through Seattle’s industrial core. Unfortunately, because of its industrial history, the last five miles of the Duwamish River towards Elliott Bay is considered one of the most polluted rivers in the nation. The U.S. Environmental Protection Agency (EPA) declared the Lower Duwamish Waterway a Superfund Site in 2001, which requires the nation’s most toxic sites to be identified and cleaned up.

Sammamish River

The Sammamish River Watershed includes land draining to Lake Sammamish (like Issaquah Creek), Bear Creek, and the Sammamish River, which empties into Lake Washington in the city of Kenmore.  Lake Sammamish and the Sammamish River supports diverse wildlife, recreational opportunities, and urban communities, including Issaquah, Sammamish, Redmond, Woodinville, Bothell, and Kenmore as well as unincorporated areas of King County.

The watershed is home to important flood risk reduction infrastructure (especially for Issaquah Creek and the Sammamish River), rich surface water management and pollution monitoring networks, and Lake Sammamish water quality sampling. Salmon conservation (WRIA 8) is also a central focus of this watershed.

Snoqualmie River

Covering the largely rural eastern portion of King County, the Snoqualmie River is made up of flows from off the Cascade Mountains. The Snoqualmie Valley is home to the iconic Snoqualmie Falls and is an important agricultural region in King County known for farming, logging, and natural beauty. The area includes flood risk reduction infrastructure together with robust flood monitoring and the Snoqualmie Fish, Farm & Flood initiative, habitat restoration, salmon recovery (WRIA 7), and natural asset preservation along trails and open lands.

The Snoqualmie River is also known for being prone to flooding. For planning purposes, the river is sometimes divided into two reaches separated by the iconic Snoqualmie Falls. Above the falls is the Upper Snoqualmie River, which includes the North Fork Snoqualmie River, Middle Fork Snoqualmie River, and South Fork Snoqualmie River. The cities of North Bend and Snoqualmie are in the Upper Snoqualmie River reach.

The Lower Snoqualmie River begins below the falls and ends at the county line between King County and Snohomish County, where the river continues until its convergence with the Snohomish River. (It’s the Snohomish River that finishes the journey to the Puget Sound.) The Lower Snoqualmie River reach flows past the rural town of Fall City and the cities of Carnation and Duval. It also receives additional flow from tributaries like the Raging and Tolt rivers.

South Fork Skykomish River

The South Fork Skykomish River is in the far northeast corner of King County. From the confluence of the Tye and Foss rivers, the South Fork Skykomish River is formed about 13 river miles upstream of the county line between King and Snohomish counties. It is a relatively unpolluted and free-flowing river running through the incorporated town of Skykomish and unincorporated communities of Grotto and Baring. The Miller River is a tributary of the South Fork Skykomish River a short distance downstream from Skykomish. The State of Washington has designated many portions of the South Fork Skykomish as scenic.

The South Fork Skykomish River is in an isolated area of King County serviced only by Hwy 2, the east-west thoroughfare traveling through Stevens Pass. Fun fact: from anywhere else in King County, the only way to visit the South Fork Skykomish River is to first leave King County. As the South Fork Skykomish River continues through Snohomish County, it meets with the North Fork Skykomish River, becoming the Skykomish River, near the town of Index. Where the Skykomish River meets the Snoqualmie River is the beginning of the Snohomish River, which empties into Puget Sound at Port Gardner in Everett.

White River

Glacier melt from Mount Rainier, combined with melting snow and rainfall from the surrounding area, creates the White River. The heavy sediment in the water from the melting glaciers gives the river its milky white color, which is where it gets the name White River. In total, the White River flows 68 miles and is part of a watershed spanning 494 square miles. It supports multiple salmon species, as well as elk, bears, eagles, and more. Within King County, the White River features flood risk reduction infrastructure, flood detection systems, sediment and stormwater management, and recreation opportunities.

Beginning in Pierce County, the White River becomes the county line boundary between Pierce and King counties where the Greenwater River joins the White River. Mud Mountain Dam, a short distance southeast of Buckley, was built on the White River by the U.S. Army Corps of Engineers in 1948, and it provides flood risk management protection on the White and Puyallup river. The White River flows through the Muckleshoot Reservation. It flows through King County and the cities of Auburn and Pacific before returning to Pierce County, where it eventually joins the Puyallup River near the City of Sumner. The Puyallup River enters the Puget Sound in the City of Tacoma.

How to Celebrate World Rivers Day

The King County Flood Control District is committed to the long-term health of area rivers by investing in flood risk reduction, habitat restoration, and community resiliency. On September 27, and throughout the year, there are many meaningful ways for you to celebrate the rivers of King County.

• Learn how you can Be Flood Ready and understand your flood risk.
• Join or organize river clean-ups or shoreline stewardship days, working with local groups and the King County Basin Steward Program to remove litter and invasive plants.
• Explore rivers responsibly by paddling on King County’s many rivers or utilizing the parks and trails along the Cedar, Green, and Sammamish rivers and the Snoqualmie Valley and Foothills trails.
• Learn about salmon recovery by reading about the KCFCD’s Cooperative Watershed Management Grant Program and how we support of WRIAs 7, 8, 9, and 10.
• Check out the Salmon Seeson page to find out where you can view salmon this fall.
• Post to social media your river stories and photos with #WorldRiversDay and #kcflooddistrict to inspire awareness.