The Soo Locks have been closed for routine maintenance and repairs. The U.S. Army Corps of Engineers will use the shutdown period, which runs through March 25, to work on the gates and electronics, and also to do structural repairs. With the annual closure, vessel traffic ceases through the Soo Locks for the season. This year during the closure, the Poe Lock will be dewatered. The last vessel to traverse the Poe Lock for the current shipping season was the 1,000 foot freighter Burns Harbor. The ship was up-bound from Burns Harbor, Indiana headed for Superior, Wisconsin for winter lay-up. It passed through on Wednesday. More than 4,500 vessels, carrying up to 80 million tons of cargo, maneuver through the locks each year.