Army Corps to raise Lake Washington to summer elevation a bit early

Published May 1, 2015

The U.S. Army Corps of Engineers will raise lakes Washington and Union to the target summer elevation a couple weeks earlier than normal due to extremely low inflows to Lake Washington.

The lake is currently at elevation 21.9 feet, which is typical for early May and consistent with normal annual operation. However, given the extreme low water supply situation (no mountain snow pack, dry recent conditions), the Corps intends to complete refill to an elevation of 22 feet in the next week or two instead of the June 1 date typically targeted.

The Army Corps needs to fill to 22 feet now to ensure that the lakes can reach that elevation.

“If we wait until late May, there probably won't be sufficient lake inflow to get us to elevation 22 feet,” said Ken Brettmann, senior water manager with the Seattle District, U.S. Army Corps of Engineers.  “In a very poor water supply year like this one, getting the lake to 22 feet is extremely important, as every inch of water in the 2-foot operating band will be needed to operate the locks for fish passage, lockages, and managing water quality concerns this year given current and expected future low lake inflows.”

The official lake level is measured at the Locks. Lake Washington levels may vary due to the natural gradient between the lake and the locks or wind that can push the lake levels up for short durations. Depending on conditions, the lake may remain at full pool through June and July.  

Vessel owners should closely monitor lake elevations and adjust mooring lines as necessary.

More information on Lake Washington’s status is available on the Corps’ Seattle District Reservoir Control Center website at

Public Affairs Office

Release no. 15-014