U.S. Army Corps of Engineers officials advise private and commercial interests along Lake Washington Ship Canal and in Lakes Washington and Union to expect earlier high water than in previous years.
Vessel owners should closely monitor lake elevations and adjust mooring as necessary.
Water managers are responding to the February 18 – June 18 closure of the small lock by filling Lake Washington nearly a month early with full refill expected in early May. With the small lock out of commission for repairs, all vessel traffic is through the large lock, which uses considerably more water. To support navigation with as few restrictions as possible, water managers are storing as much water upstream as allowed.
"Targeting earlier refill makes it much more likely that 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.
For more information about activities at the Locks, visit our public website or follow us on Facebook and X.
Release no. 25-006