The City of Bellevue declared an emergency in 2023 and completed an emergency project (Phase 1) in June 2024 to address public safety at the Lakemont Boulevard crossing of Coal Creek. The failing culvert under Lakemont Boulevard placed the roadway at risk of failure. As a result, a new bridge was constructed over Coal Creek to ensure the stability of Lakemont Boulevard. The current project (Phase 2) addresses non-emergency culvert removal and stream restoration.
Why This Project is Needed
To complete the emergency work (Phase 1), various permits were obtained. In particular, a Washington State Department of Fish and Wildlife (WDFW) Hydraulic Permit Approval (HPA) was issued to perform the emergency work. The terms and conditions of the HPA identified that the Coal Creek culvert must be replaced with a fish passable design after Phase 1 is completed. This project, Phase 2, will remove the existing 60” diameter failed culvert and restore Coal Creek to meet this obligation.
Project Location
This project is located at Lakemont Boulevard crossing Coal Creek, adjacent to the Red Town Trailhead of Cougar Mountain Regional Wildland Park.
Project Funding
The project is funded through City resources identified in the Capital Improvement Plan (CIP) Budget for Infrastructure Rehabilitation.
Project Phases
Phase 1: The corrugated metal pipe carrying Coal Creek deteriorated. Additionally, storm events exacerbated embankment settlement around the culvert, creating a road safety hazard from pavement deformation. A new bridge was constructed (Oct. 2023 - June 2024) spanning the creek to provide greater structural stability to the roadway by placing its foundation outside of the influence of the culvert.
Phase 2: Restore the natural channel and improve fish passage and habitat in Coal Creek through the proposed bridge meeting the per guidance and requirements from the Washington State Department of Fish and Wildlife (DFDW).
- Phase 2.1: Must-Do Cost Effectiveness Analysis – Currently underway and includes the identification of alternatives to restore Coal Creek as the existing 60-inch culvert resides on an old mine shaft cap.
- Phase 2.2: Design – Once a preferred alternative is selected, design and permitting is expected to proceed following WDFW fish passage guidelines.
- Phase 2.3: Construction – The final phase will involve removing the existing 60-inch failed culvert and restoring Coal Creek to a more natural condition.
Project Solutions (Alternatives)
Due to the complexity of the proximity of the existing mine shaft cap under the 60-inch culvert, alternatives are still being evaluated. Ongoing updates will be provided.
Project Timeline
- Phase 1: Bridge construction started Oct. 24, 2023.
- Phase 1: Bridge construction completed June 2024.
- Phase 2: Must-Do Cost Effectiveness Analysis, Q1 2025 - Q4 2025
- Phase 2: Design and Permitting, Q1 2026 – Q2 2027
- Phase 2: Construction, Q3 2027 – Q2 2028
Opportunities for Public Input
A community open house will be scheduled for Q3 2025 to provide a project update on alternatives being considered and answer any questions.
