As U.S. Army Corps of Engineers’ flood fighters were supporting local communities in Skagit, Whatcom and Snohomish counties over the weekend, Seattle District water managers were busy regulating flows at five dams to reduce downstream flood risk.
“Seattle District’s Reservoir Control Center worked 24-hour operations over the weekend to monitor and regulate Howard Hanson, Mud Mountain, Upper Baker, Ross and Wynoochee dams,” said Western Washington Senior Water Manager Jon Moen.
The Corps owns and operates Howard Hanson and Mud Mountain dams and directs operations of the utility-owned projects during flood events per established agreements.
The Corps began regulating City of Aberdeen-owned Wynoochee Dam early February 1. During peak operations the inflows to the dam were above 8,000 cubic feet per second (cfs) and Corps water managers were holding back nearly this entire amount, releasing only 200 cfs. Corps officials returned control to Tacoma Public Utilities, which operates the dam for the city, afternoon February 3.
In the Skagit River basin, the Corps took control of the Upper Baker and Ross dams early February 1. During peak inflows, Corps officials held back about 19,000 cfs at both dams.
“Holding back these flows helped reduce downstream Skagit River flows at Concrete, Washington, from about 114,000 cfs to 78,000 cfs. This is equivalent to a river stage reduction at Concrete of over five feet,” said Moen.
Operations were returned to Puget Sound Energy-owned Upper Baker Dam and Seattle City Light-owned Ross Dam February 2.
At Howard Hanson Dam, Green River inflows rose above 10,000 cfs and Corps water managers held back over 4,000 cfs during the event’s peak. Mud Mountain Dam inflows for the White River were above 9,500 cfs and managers targeted releases below 6,000 cfs.
“Public safety is our number one priority and our next concern is reducing the reservoir pools,” said Moen. “You’ll continue to see elevated outflows as we reduce pools to make reservoir space as we anticipate potential flooding later this week.”
The National Weather Service issues Flood Watches and Warnings.
Reservoir data from Corps reservoirs are available on line at:
Public Law 84-99 enables the Corps to assist state and local authorities in flood fight activities and cost share in the repair of flood protection structures. The purpose is to prevent loss of life and minimize property damage associated with severe weather.
Private citizens seeking sandbags should contact their local cities or counties.