SAULT STE. MARIE, Mich. (AP) — The Soo Locks in Sault Ste. Marie are shutting down to marine traffic to allow the U.S. Army Corps of Engineers to perform critical maintenance.

Sault Ste Marie, Mi located in Chippewa County on the Canada-US border, The Soo Locks date back to the mid-1800s. 90% of the United States Iron Ore move thru the Soo Locks. Boats are lifted the 21-Foot difference between Lake Superior & Lake Huron. You may notice the bridge to Canada has no vehicles on it due to the border being closed by covid 19

READ MORE: Here Is The Top 'Should I...' Question Googled In Michigan In 2021, AT&T Reports

The locks on the St. Marys River between Lake Superior and Lake Huron are expected to be closed from Saturday to March 25, according to the Army Corps of Engineers.

The complex consists of several locks that raise and lower vessels between Superior and Huron, which have a 23-foot elevation difference.

READ MORE: GM Secures Tax Abatement For Proposed $1.3B Orion Assembly Plant Investment

Each year, the Army Corps of Engineers uses the winter months for maintenance. Work this winter is expected to include hydraulic steel structure inspections, pier inspections, preventive maintenance on electrical and mechanical systems, structural repairs, and seal replacement.

“It is a difficult time in terms of weather to complete this work, but it keeps this important national infrastructure project operating during shipping season,” Soo Area Engineer Kevin Sprague said.

More than 4,500 vessels, carrying up to 80 million tons of cargo on the Great Lakes, use the locks each year.

MORE NEWS: Chief White Says 'There's Reason To Believe' Remains Found In Detroit Belong to Missing Mother Latima Warren

© 2021 Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.