The Valley Creek at NE 20th Street Flood Control Project is an important flood reduction effort by the City of Bellevue and is high on the City’s Capital Improvements Projects list due to frequent flooding of NE 21st Street at Valley Creek. As part of a larger mitigation plan, the City of Bellevue Utilities Department replaced and upsized the existing culvert at NE 21st Street and removed accumulated sediment and vegetation overgrowth in 2023 under the Valley Creek Culvert Replacement and Stream Restoration Project. This work helped restore the creek channel, convey flows during large storms, and improve fish passage. The culvert project at 21st Street has been completed, and efforts are now focusing on the culvert located at NE 20th Street.
Why this project is needed
The Flood control work that was done on NE 21st Street reduces but does not prevent future potential road flooding along NE 21st Street east of Valley Creek or in Valley Creek north of 21st Street. This Valley Creek at NE 20th Street Flood Control project will provide additional reductions in flood levels and frequency or risk of road flooding during large storms.
Project Location
The project is situated in the BelRed area; Valley Creek flows beneath NE 20th Street, west of 140th Avenue NE, near Highland Park. The existing culvert is downstream from some of the recent culvert upgrades at NE 21st Street and is key to allowing water to continue along the creek.
Project Funding
The King County Flood Control District provided funding for this project. The remaining funds will be provided by the City of Bellevue Stormwater Utility.
Project Approach and Timeline
The project will be completed in three phases:
- Phase 1: Alternative Analysis – This phase is now complete. It included studying the problem and exploring possible solutions. Consultants evaluated the condition of the creek and culvert, conducted surveys, and modeled the stream’s flow to identify the best way to reduce flooding and reduce future maintenance needs.
- Phase 2: Design and Permitting – Following solution selection, the next step is to design how the solution will be implemented, making sure to address traffic, environmental, regulatory, and public safety concerns. This phase is expected to be complete by late 2029.
- Phase 3: Construction – The final phase will involve replacing the culvert based on the selected alternative. The City will ensure that the work is completed with minimal disruption to the surrounding area. This phase is expected to be complete by late 2031
Selected Alternative
A 19-foot wide by 50-foot long 4-sided Box Culvert with regrading of the stream profile to correct the slope of the stream has been selected as the preferred alternative
Project Benefits
The project will benefit both the environment and the community:
- Flood prevention: By improving the flow of water through the culvert, the project will help reduce the risk of flooding during heavy rain, protecting nearby businesses and streets.
- Improved fish passage: Upsizing the culvert will help resident fish and salmon access critical spawning and rearing habitat through a more natural habitat.
- Improved Natural Stream Process and Habitat: Improving natural stream processes (i.e., sediment transport), enhancing riparian and floodplain habitats.
- Supporting regional goals: The project aligns with broader environmental efforts to restore salmon populations and improve the health of local waterways.
Opportunities for Public Input
The City of Bellevue values the community's input on this project. There will be several opportunities to provide feedback in the next phase of the project. During the construction phase, Residents will be notified in advance of any road closures or construction impacts, and the City will work to minimize disruptions. Your input is essential in helping the City balance the needs of the environment with the daily lives of residents.
