A Corps of Engineers employee scrapes barnacle buildup along the entire length of the 800-foot-long, 8-foot-wide by 14-foot-tall filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. The Corps of Engineers is mandated to scrape the barnacle buildup once a year to make the large lock safer for juvenile salmon going through it as they migrate out to sea.