Dam Safety
Dam Safety Program overview
Seattle Public Utilities (SPU) owns and operates a portfolio of dams to provide drinking water and drainage benefits to our region. SPU is dedicated to ensuring that all our dams are designed, constructed, operated, and maintained with your utmost safety in mind. SPU continually inspects, evaluates, and documents the design, construction, operation, maintenance, rehabilitation, and emergency preparedness for each dam. SPU has developed and implement a Dam Safety Program to reduce the likelihood and consequences of a dam failure.
The mission of the SPU Dam Safety Program is to ensure safe operation of the dams, appurtenances, reservoirs, and the Cedar Moraine embankment owned by SPU.
The program goals are to:
- Comply with strict federal and state regulatory requirements.
- Inspect, monitor, maintain and operate the dams to minimize the chances of loss of water supply or flooding downstream, and prevent these conditions from developing if possible.
- Respond to dam emergencies by using rehearsed emergency action plans and other tools.
- Develop emergency action plans in partnership with other agencies.
- Ensure that the Tolt Dam and Lake Youngs Dam Failure Warning Systems are being operated and maintained appropriately.
- Plan and invest in state-of-the-art surveillance and monitoring equipment to ensure safe dam operations, which allows the City to respond to emergency conditions.
Dam monitoring and emergency action plans
SPU has comprehensive dam safety, monitoring and surveillance equipment in place. Scientific instruments are installed to continuously monitor dam performance by measuring reservoir levels, groundwater within dams, and stream flows. Operation crews perform daily visual inspections on all dams and report unusual conditions and high instrument readings to dam engineers. Federal and state regulators work with our SPU staff to perform annual inspections to ensure safe operating conditions.
All our dams meet current engineering standards and are in compliance with state and federal regulations.
SPU has developed emergency action plans for our high hazard potential dam facilities. These plans are updated periodically, in partnership with local emergency management agencies, King County, the National Weather Service, and state and federal dam regulators.
For more information about SPU’s Dam Safety Program, contact Andre Ball, Dam Safety Supervisor at andre.ball@seattle.gov.
For emergency related questions, please contact your local emergency management agencies.
Related links
City of Seattle sites
- Cedar River Watershed (Seattle Public Utilities)
- Cedar Falls Hydroelectric Project (Seattle City Light)
- Lake Youngs Reservoir (Seattle Public Utilities)
- Tolt River Watershed (Seattle Public Utilities)
- Tolt Dam (Seattle Public Utilities)
- South Fork Tolt Hydroelectric Project (Seattle City Light)
- Tolt Dam Early Warning System (Seattle Public Utilities)