The feds have decided that the Upper St. Anthony Lock in Minneapolis will reopen with ice-out this year until a congressionally mandated closure date of June 10.

The U.S. Army Corps of Engineers announced its decision Wednesday. Col. Dan Koprowski said that reopening the lock for an expected two and one-half months would give river shippers additional time to stockpile materials. That follows one of the shortest navigation seasons ever recorded by the corps on the upper river in 2014.

“We fully recognize that this decision will be applauded by some and criticized by others,” Koprowski said in a statement.

The chief beneficiary of that decision is likely to be Aggregate Industries, which operates a sand and gravel yard about two miles above the lock at St. Anthony Falls. It ships those materials from its quarries on Grey Cloud Island, and they are used in concert with other nearby companies to supply concrete and other building materials to the Minneapolis area market. Another beneficiary is Northern Metals, which collects metal at its upper riverfront scrapyard for shipment to southern mills by river or rail.

A coalition of groups opposing the spread of invasive carp up the Mississippi River advocated for closing the lock permanently with the closure of shipping for the winter. They say the upper lock is the last barrier acting as a defense against carp.

Congress mandated the closing by June 10, citing the carp threat.  But the corps said it concluded that the risk for the short period this spring was minimal compared to the benefit to businesses.

The reopening will occur in the spring, when flows down the river are generally high, making it harder for carp to move upstream. But those same flows can also hamper navigation; last spring the corps closed its three locks in Minneapolis when the current hit 40,000 cubic feet per second.

When the upper lock closes, the corps will cut locking hours at the Lower St. Anthony Lock and Lock No. 1 (Ford) from 19 hours to 10 hours daily.       

(Photo: A barge locked through the upper falls in 1968.)