SEATTLE -- U.S. Army Corps of Engineers officials began Lake Washington’s annual summer refill operations Feb. 15.
Vessel owners should closely monitor lake elevations and adjust mooring lines as necessary.
Water managers are targeting a typical annual refill of Lake Washington to an elevation of 22 feet this spring. Fill rates and target elevations may vary through May based on changing conditions.
Achieving full refill is especially important this year due to the low snowpack in the Cedar and Sammamish River basins, so USACE is currently aiming to be full by April 1, earlier than typical. Refilling the lake to 22 feet will help meet increased summer water use, provide water necessary for fish passage, navigation, and salinity control.
Private and commercial maritime interests along the Lake Washington Ship Canal and in Lakes Washington and Union should expect a gradual rise from the winter level of 20 feet until the 22-foot target refill elevation is reached around April 1.
The official lake level is measured at the Locks. The 22-foot target elevation is referenced to the local project datum, equivalent to 18.75 feet referenced to the North American Vertical Datum of 1988.
Lake Washington and Lake Union levels may vary due to the natural gradient between Lake Washington and the Locks or wind that can push the lake levels up for short durations. Depending on conditions, the lake may remain at the maximum target elevation through July.
More information on Lake Washington’s status is available on the USACE Seattle District Reservoir Control Center website.
For more information about activities at the Locks, visit our public website and/or follow us on Facebook.
Release no. 26-004