SEATTLE -- The large and small locks will close to all marine traffic eight hours, 8 a.m. to 4 p.m., May 29 to inspect and close a saltwater drain screen structure.
The structure, immediately upstream of the locks, prevents salmon from entering the locks’ saltwater return intake. Divers will close 10, 10-foot-by-6-foot doors and inspect the 30-by-60 foot curved-front, mesh screen structure. U.S. Army Corps of Engineers officials close the doors and inspect the structure annually before salmon migration season begins mid-June. Divers will perform monthly inspections until the doors are opened mid-September.
The inspections require lock closure to all but emergency vessels on emergency calls. The staff will complete work as quickly and safely as possible. Monthly inspection closures will be posted on the Seattle District’s public web site at http://bit.ly/BoaterInfo and on the locks’ Facebook site at www.facebook.com/chittendenlocks.
The saltwater drain delivers water to a diffuser well beneath the fish ladder to provide flow for fish passage. It was thought fish could sometimes access the diffuser well through the saltwater drain intake, which does not have an exit.
“We closed off some potential well access points and in 2008 installed the screen,” said locks’ fisheries biologist Kaitlin Whitlock. “We continue to research ways to ensure salmon can pass upstream to spawning grounds.”
Another project projected to help with the Corps’ salmon migration environmental stewardship is replacement of the filling culvert valves. Original to the century-old locks, the valve gates open and close, allowing water to flow through the large tunnels to raise and lower levels in the chamber. The new gates will allow flow regulation the old system did not.
The upgrade will require several extended 45-day closures to replace the filling culvert valves. The projected closure dates are:
2019
October 12 through November 30
2020
February 12 through April 2
October 12 through November 30
2021
February 12 through April 2
November 9 through November 24
For more information about activities at the Locks, visit the locks’ web site at http://bit.ly/BallardLocks. Also follow the locks on Facebook and Twitter, http://twitter.com/ChittendenLocks.