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 Galli’s-Dykstra Feasibility and Repair Project along the Green River.
Protecting Auburn and Enhancing Habitat: Completion of the Galli’s-Dykstra Levee Project
In 2021, the Galli’s-Dykstra Levee Project, in Auburn, was successfully completed to address low areas along the levee. Associated revegetation efforts were completed between 2022 and 2023. The project is a vital investment in community safety and environmental stewardship along the Green River.
Supervisor Pete von Reichbauer, who represents South King County, shared his support for the project: “The Galli’s-Dykstra Project exemplifies the Flood Control District’s commitment to safeguarding our communities while protecting our environment. By raising the levees and addressing low-lying areas, we have reduced the flood risk for homes, businesses, and public infrastructure in Auburn. I am pleased that this project also improves salmon habitats, ensuring that our investments benefit both the community and the natural environment.”
The Galli’s and Dykstra levees are located on the left bank of the Green River, providing flood protection for residential neighborhoods, commercial properties, and agricultural areas in Auburn and unincorporated King County. This project ensures that the levees provide a uniform level of flood risk reduction for the community while incorporating habitat enhancements to benefit salmon and other wildlife.
Project Background
Concerns about low areas along the Galli’s and Dykstra levees first arose in 2013, when the City of Auburn requested an evaluation of levee conditions. The 2019 Green River System-Wide Improvement Framework (SWIF) identified these low spots as an interim flood risk that required corrective action to ensure the levees could safely contain high flows and meet inspection standards.
King County, serving as the KCFCD service provider, launched the Galli’s-Dykstra Feasibility and Repair Project to address these risks. Initial studies identified three low areas along the 1.3-mile stretch of levee:
- Area A: ~1,000 feet near Dykstra Park and adjacent multi-family buildings, requiring up to 2.75 feet of levee height increase.
- Area B: ~600 feet south of Area A, adjacent to single-family homes, requiring up to 1 foot of levee height increase.
- Area C: ~400 feet further south, also adjacent to homes, requiring up to 1 foot of levee height increase.
Project Goals
The Galli’s-Dykstra Project was designed to:
- Eliminate low points along the levees to ensure a consistent level of flood protection.
- Increase flood containment capacity to 12,000 cfs plus three feet of freeboard, protecting against a 100-year flood event.
- Reduce flood risks for homes, businesses, public infrastructure, and farmland in Auburn and unincorporated King County.
- Enhance environmental conditions, including riparian planting of native shrubs and trees to support salmon habitat where space allowed.
Project Details and Benefits
The completed improvements include:
- Raising the levee prism using compacted fill to correct low spots and create a uniform levee crest.
- Re-establishing grass cover on the levee and planting native vegetation to improve habitat.
- Revegetation of an approximately 4-acre parcel along the Green River 1.5 miles downstream of the levee repair location
- Improved public safety, ensuring the levees meet federal inspection standards and can reliably protect the surrounding community.
Construction was completed in phases to minimize disruption to local residents. Area A, near Dykstra Park, was addressed first, followed by Areas B and C, which are adjacent to private homes and required careful coordination to respect property access and views.
Community and Environmental Impact
This project not only reduces flood risk for the Auburn community but also supports salmon recovery efforts in the Green River. By creating a more resilient levee system with opportunities for native vegetation, the KCFCD continues to balance public safety with environmental stewardship. With the completion of the Galli’s-Dykstra Feasibility and Repair Project, the KCFCD reaffirms its commitment to proactive flood risk reduction and sustainable river management for the residents of King County.