By Steven Schauer, Deputy Executive Director and King County Staff
The King County Flood Control District (KCFCD) has been working diligently since its creation in 2007 to safeguard our communities from flooding. The KCFCD, in collaboration with King County as service provider, has spearheaded over 370 capital projects aimed at mitigating the risk of levee and revetment failures. These projects, along with the operation and maintenance of over 500 flood protection facilities, cover 118 linear miles and approximately 800 acres of land crucial for flood mitigation.
While the KCFCD’s weekly blog typically shares information about new and ongoing projects, each month, we will shine a spotlight on a completed project that is quietly doing its job to safeguard our community against the threat of flooding. The project we’re covering this month is the Tolt Pipeline Protection Project near Duvall.
Tolt Pipeline Protection Project
Nestled in the picturesque Snoqualmie River Basin, the Tolt Pipeline Protection Project stands as a testament to the KCFCD’s commitment to protecting life, property, and essential infrastructure while preserving our natural environment. Constructed in 2018, this project addresses a critical need: safeguarding Seattle Public Utilities’ Tolt River water supply pipelines and adjacent farmlands from the ever-present threat of bank erosion and channel migration.
“The vital Tolt Pipeline Protection Project not only ensures a reliable water supply for Seattle Public Utilities (SPU) but also protects the interests and well-being of all District 3 residents,” said Sarah Perry, KCFCD’s Vice Chair and Supervisor for District 3. “The collaboration and dedication demonstrated by staff from the District, King County, and SPU was exemplary. Their hard work and commitment have safeguarded crucial infrastructure and enhanced our community’s resilience. I am very grateful to the Snoqualmie Indian Tribe, the landowners, and the many stakeholders who were also engaged for their unwavering efforts in bringing this project to fruition.”
A Vital Lifeline for the Region
The Tolt Pipeline, a crucial conduit for approximately 30% of SPU’s water supply, serves a wide array of communities, including Bellevue, Bothell, Redmond, and Seattle. With such a significant portion of the region’s water supply at stake, the importance of this project cannot be overstated.
Project Goals and Objectives
At its core, the Tolt Pipeline Protection Project aims to:
- Protect the Tolt River Water Supply Pipeline: By reconstructing approximately 1,200 feet of the Winkelman Revetment on the north side of the Snoqualmie River, the project ensures the pipeline remains shielded from the river’s erosive forces.
- Minimize Long-term Maintenance: The design and construction focus on durability and sustainability, reducing the need for frequent repairs and associated costs.
- Enhance Aquatic Habitat and Agricultural Land: Beyond infrastructure protection, the project seeks to benefit the surrounding ecosystem and farmland, aligning with the KCFCD’s multibenefit approach to flood mitigation projects and the broader goals of the King County Flood Hazard Management Plan.
Innovative Engineering and Environmental Stewardship
Construction crews placed 760 large boulders and log structures along the river to reinforce the bank, effectively combating erosion and river migration. Additionally, a collapsed culvert at Deer Creek was replaced and upgraded with a floodgate to ensure fish passage is unimpeded, enhancing local aquatic habitats. Native trees and shrubs were planted along the riverbank, not only providing extra stability but also contributing to the local ecosystem’s health and resilience. Endangered Species Act (ESA) listed Chinook salmon are among the beneficiaries of improved aquatic habitat conditions and fish passage resulting from the project.
Community Collaboration and Future Outlook
This project exemplified the collaborative spirit between KCFCD, King County, SPU, Tribes, local landowners, and environmental organizations and agencies. The design phase incorporated feedback from various interested parties, ensuring that the project met regulatory requirements and community needs.
With funding provided by the KCFCD, the project’s budget was approximately $10.2 million. This essential project is a reminder of the intricate balance between infrastructure development and environmental preservation. The Tolt Pipeline Protection Project is more than a construction endeavor; it is a promise to our communities, reducing flood and erosion risks, ensuring a reliable water supply and a thriving natural habitat for generations to come.