U.S. Army Corps of Engineers officials advise boaters to expect earlier high water levels

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

Water managers are responding to this year’s snow drought conditions by filling Lake Washington nearly a month early, with full refill expected on May 1. Per Washington State Department of Ecology,

On April 8, 2026, Ecology issued a drought declaration for all watersheds in the state due to low snowpack and multiple years of precipitation deficits. This is the state’s fourth consecutive drought declaration – a record under the current drought framework established in 1989. https://ecology.wa.gov/water-shorelines/water-supply/water-availability/statewide-conditions/drought-response

The lake level is under additional stress this year because the Hiram M. Chittenden Locks’ large lock is limited to full lockages only until a damaged area of the lock wall is repaired, requiring greater water usage. Filling early will help the Lake Washington Ship Canal support navigation through spring and summer with as few restrictions as possible despite these difficulties.

"Targeting earlier refill guarantees the lake will reach its normal full elevation target of 22 feet," said Kyle Comanor, Seattle District's western Washington senior water manager. "Refilling the lake to this elevation will help meet increased summer use, providing water necessary for fish passage, navigation and salinity control."

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 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 the maximum target elevation through June and July.

More information on Lake Washington's status is available on the Seattle District Reservoir Control Center website.

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