Corps water managers take flood control management of three dams

Published Nov. 22, 2017

SEATTLE – U.S. Army Corps of Engineers water managers from the Seattle District’s Reservoir Control Center are regulating flows for Wynoochee, Ross and Upper Baker Dams.

The engineers began regulating the flows for the Western Washington dams November 21 at Wynoochee and November 22 at Upper Baker and Ross. Corps operation of these utility-owned projects occurs during flood events per established protocols.

The Corps began regulating flows from the Tacoma Public Utilities-owned Wynoochee Dam in the afternoon and cut outflows to 3,500 cubic feet per second (cfs) while inflows to the dam reached 10,000 cfs. This operation keep river flows below flood stage at the official forecast location near Montesano, Washington.

Operations at Seattle City Light-owned Ross Dam and Puget Sound Energy-owned Upper Baker dam have helped to reduce downstream flows on the Skagit River by about 25,000 cfs, equivalent to a downstream river stage reduction at Concrete, Washington, of about 3.5 feet.

In addition to flood risk reduction operations in the Skagit and Wynoochee basins, the Corps owns and operates Mud Mountain and Howard Hanson dams in the White/Puyallup and Green/Duwamish basins for flood risk reduction.

Built by the Corps on the White River in the 1940s, Mud Mountain Dam currently reduces flood risk to homes and businesses of about 400,000 people.

The Corps completed building Howard A. Hanson Dam in 1961 near the Green River’s headwaters in King County. With major flooding under control, the Green River Valley has become attractive to industry, raising its economic worth substantially.

Seattle District water managers work in the Water Management Section and are responsible for monitoring and regulating several Puget Sound region rivers. This requires a complex computer network to collect data from multiple locations and gages every hour. For more information or to view data, visit

Bill Dowell

Release no. 17-056