The City of Bellevue’s "Lake Lines" are a portion of the wastewater system located along the shorelines of Lake Washington and Lake Sammamish. Approximately 15 miles of the lake lines run along the Lake Washington shoreline, connected to 15 pump stations and eight flush stations. These sewer pipes are either underwater or on land adjacent to the lake.
Most of the Lake Washington lake line was constructed in the 1950s and '60s to prevent raw sewage from being discharged into the lake. Half a century later, the line now serves more than 1,000 community members in Bellevue and neighboring communities. However, the pipes that constitute the line are aging, and their location creates challenges for repair and replacement.
Why lake line plan is needed
Without advance planning, the lake line will begin to fail, potentially causing loss of service to residents and risk to the sensitive lake environment. Bellevue Utilities is developing a management plan for the repair, replacement, and maintenance of the system that will lay groundwork for future design and construction projects. The plan will help ensure we can continue to provide safe and reliable sewer service to the community and protect public health and the delicate Lake Washington ecosystem.
Potential Solutions
Potential solutions could take place in the lake, on land and on individual properties. It is important to note that different areas of the system will have different selected alternatives. There will not be one alternative selected for the entire lake line.
Alternative 1: In water
For pipes below the ordinary high-water line of Lake Washington, potential solutions could include monitoring the condition of the lines or repairing or replacing them. Methods could include installing gravity sewer lines via open-cut trenchless (below-ground drilling) construction or trenchless rehabilitation via cured-in-place pipe, spiral wound pipe, slip lining, pipe bursting or other, emerging technologies.
Alternative 2: On shore
For pipes generally near homes and the shoreline, above the ordinary high-water line of Lake Washington, potential solutions could include monitoring the condition of existing lines or repairing or replacing them. Methods could include installing new gravity sewer lines via open-cut trenchless construction or a vacuum sewer system.
Alternative 3 - Upland
For portions of the conveyance system upland of homes and within the general vicinity of the public right of way, potential solutions could include monitoring the condition of existing lines, repairing existing lines or replacement of lines. Methods could include installing a new gravity sewer line via open-cut trenchless construction or installing a new grinder pump or vacuum sewer.
What to Expect
The project team is reviewing information about the lake line system to develop strategies for future repair, replacement or maintenance. The lake line will be divided into sections for analysis and planning. Some sections may not require work; others will require repair, replacement or maintenance.
The city will prepare an environmental impact statement, in accordance with the State Environmental Policy Act, for each strategy, while developing the management plan.
The development of the lake line management plan will prepare for future design and construction projects. The purpose of the plan is to develop and document a long-term approach for rehabilitation or replacement of the lake lines, including financial and policy components, and will incorporate mitigation recommendations from the environmental impact statement into the plan.
Project location
This project is located in Lake Washington adjacent to the waterfronts of the following areas (identified on map below):
- Bellevue
- Medina
- Hunts Point
- Yarrow Point
- Beaux Arts Village
- Small portion of unincorporated King County
Timeline
- 2020-22: Project planning
- June 2022: Environmental impact statement scoping
- July-August 2022: EIS scoping comment period, management plan outreach
- September-January 2022: Management plan prioritization and alternatives development
- September 2022-February 2023: Prepare draft EIS
- February 2023: Comment period for draft EIS
- January-June 2023: Identify preferred alternative for management plan, with outreach
- March-September 2023: Prepare final EIS
- November 2023: Present management plan and EIS
Public engagement
The city will use multiple channels to communicate important information and updates throughout the project, including this page, mailed notices, online public meetings and possible in-person meetings. You can subscribe for email or text updates.
Bellevue Utilities is committed to providing up-to-date project information throughout the project and EIS process. As the project continues, we look forward to your comments and feedback.
- Environmental Impact Statement Open House: For information about the EIS. For questions about the EIS, please contact Reilly Pittman (LakeLineEIS@bellevuewa.gov or 425-452-4350).
- Management Plan Comments: Residents and affected property owners are invited to weigh in on the management plan via an online survey. Project manager Angela Chung (LkWaLakeLine@bellevuewa.gov, 425-452-4320) will also take questions about the plan.