Video: Last shipping freighter of the season on the Great Lakes comes to port

The shipping season on the Great Lakes has officially come to a close for the winter.

The Soo Locks in Sault Ste. Marie will be closed until March 25 for "critical maintenance" on the lock structures, the U.S. Army Corp of Engineers announced this week.

This year during the closure, the Poe Lock will be drained, officials said. A variety of other maintenance projects will be done in preparation for it to reopen in March.

"The Soo Locks are vital as a single point of passage for shipping from the upper to lower Great Lakes," Lt. Col. Greg Turner, district engineer, said in a statement. "Maintaining our existing infrastructure and building the new lock are keys to providing a resilient link in the Great Lakes navigation system now in the decades to come."

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Corps officials said the MacArthur Lock has repairs partially completed to the gate operating machinery. Additional work taking place includes inspection of gate anchorages, electronics updates and operating shelter maintenance.

Work on the Poe Lock includes gate structural repairs, gate anchorage link replacement, gate stressing checks, gate tieback installation, repairs to concrete gate sills, emptying valve and valve machinery repairs, electronics updates and debris removal from the drainage system. The Poe Lock will also undergo a formal periodic inspection, officials said.

The MacArthur Lock is 80 feet wide and 800 feet long while the Poe Lock is 110 feet wide and 1,200 feet long, allowing 1,000-foot freighters to pass through the 21 feet to and from Lake Superior and Lake Huron around the St. Mary's River Rapids between Michigan and the Canadian province of Ontario.