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USACE announces faster drawdown of Lake Washington lake levels

Published Sept. 3, 2020

Seattle District, U.S. Army Corps of Engineers’ officials have announced Lake Washington elevation reductions in preparation for the Suquamish Tribal fishing season and Corps Emergency Scour Repair project that begins September 13 and 15, respectively. The drawdown has begun and the projected lake level should reach 20.25 ft. by September 12.

The Suquamish Tribe commercial net fishers will be exercising their reserved Treaty right to fish in and around the waters of Shilshole Bay and the Lake Washington Ship Canal.  Treaty commercial fishing could begin as early as Sunday, September 13th and continue through October, with the most active period occurring during the month of September.  Fishing nets can be deployed during night-time hours, but are mostly deployed during the day-time hours. Boaters should be alert for nets strung along the surface of the water with small white corks and flanked by larger, often orange to red-colored floating buoys.  Boaters are asked to use caution and patience when navigating the area during his time.

The Corps plans to maintain a spill buffer until late October, in an effort to not interrupt tribal fishing and to allow the contractor to safely complete the repairs.  

The Emergency Scour Repair Project will correct concrete erosion near the Hiram M. Chittenden Locks fish ladder, which was first observed in a 2019 survey. The damage worsened in February 2020, after a historic inflow event, caused by back-to-back winter rainfall events that resulted in free-flow spilling at the Locks.

Lake residents and users will notice a faster drawdown than typical years to prepare for the repair project, which will occur near the Locks’ spill gates. Corps officials are recommending floating homeowners, others with floating structures and vessels moored on lakes Washington and Union and along the Ship Canal to prepare for a faster rate of lowering water levels.

“Typically, the lake elevation lowers gradually throughout the summer and early fall due to normal water use at the Locks. However, this summer the lake elevation has remained higher than normal due to cooler weather and healthy inflows,” said USACE regulator Eric Zimdars. “The upcoming activities at the Locks have necessitated the action to draft the elevation down at this time.”

The goal in drawing down the lake levels is to create a buffer for when the rain returns to our region and allow the Seattle District’s Water Management section enough lead time to coordinate with the contractors to move their equipment and the Tribes to remove their fishing nets before a spill occurs.

“By drafting down the lake to 20.25 ft, we project that our need to spill will be greatly reduced,” said Zimdars. “The ideal situation is completion of the repair project and the Tribal fishing season without having to open our spillgates.”

The scour repair work is slated to run from September 15th to October 15th. During the project residents in the area of the Locks may hear construction noise during the evening hours.

Individuals who wish to monitor Lake Washington lake levels can visit https://www.nwd-wc.usace.army.mil/nws/hh/www/index.html.


Contact
Dallas Edwards
(206) 764-6958
dallas.d.edwards@usace.army.mil

Release no. 20-115