- Emergency Water Supply Master Plan
- Attachment 1: Seismic Vulnerability Assessment
- Attachment 2: Emergency Water Supply Planning
- Attachment 3: Public Engagement Survey Report
Why do we need a Master Plan?
Bellevue’s water system and the regional water supplies are vulnerable to natural disasters, particularly earthquakes. Bellevue receives its water from Seattle Public Utilities (SPU), via contract with Cascade Water Alliance. SPU manages the regional drinking water delivery system, while Bellevue Utilities manages the city's local water infrastructure.
In late 2018, SPU issued a Seismic Study report which found that, in the event of a major disaster or earthquake, regional water service may be completely unavailable for 3 weeks, followed by a long recovery period with only partial service for months.
The City of Bellevue recently completed a seismic vulnerability assessment estimating the potential local water supply impacts in Bellevue. Because of the possibility of hundreds of main breaks and the time needed to repair them, the assessment anticipates a long system recovery period following a major event. The figure below demonstrates the long recovery period that might be expected if a Seattle Fault earthquake happened in Bellevue with the existing system.
What will the Master Plan accomplish?
To prepare for these threats to Bellevue's water system and supply, the Master Plan will help the City accomplish the following objectives:
- Identify water system risks and potential impacts to the community
- Establish long-term goals for improved water system performance, and minimum levels of service after an event
- Propose mitigation actions and investment levels to improve resiliency over the next 50-years
Potential improvements may include adding more emergency groundwater wells, constructing a resilient “backbone” of more resilient pipes, adjusting the City’s existing program to replace aging water mains, and other potential improvements.
Developing and approving a plan that can direct Utility investments and serve Bellevue’s long-term community needs requires proactive community engagement. Input from over 1,000 customers during community engagement in late 2021 (summarized in Attachment 3) has helped to inform both the type of projects proposed by the Master Plan, and how the City prioritizes potential improvements. Public review of the entire draft Plan occurred in Nov. 2022 - Feb. 2023 through the State Environmental Policy Act (SEPA) process.