The City of Bellevue is in process of developing an Emergency Water Supply Master Plan. The Plan will guide the City's actions to help improve our water system resilience over the coming decades and ultimately reduce impacts to the community from a severe earthquake or other disaster.
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 will require proactive community engagement. Input from Bellevue's community will help to inform both the type of projects the City undertakes and how we prioritize potential improvements.