A barge operator believes it has found a sunken barge in the Ohio River near Pittsburgh, one of 26 that broke loose and floated away during weekend flooding, company officials said Tuesday.

Crews used sonar to locate an object in a stretch of river north of the city, which Campbell Transportation Company Inc. said it presumes to be its missing barge.

The river remained closed to maritime traffic while the company worked to salvage the runaway barges.

Cmdr. Justin Jolley, of the U.S. Coast Guard’s marine safety unit in Pittsburgh, said Tuesday that once the object in the river is confirmed to be the missing barge, “we’re hopeful we can reduce the security zone to that area and allow traffic to resume.”

Seventeen of the barges are secure and under control, while seven remain positioned against the Emsworth Locks and Dam and one is pinned against the Dashields Locks and Dam, the company said.

“We are actively developing a recovery plan for all affected vessels, which will be implemented when safe for the recovery workers, barges and the public,” said Gary Statler, the company's senior vice president for river operations.

Jolley said the company began retrieving barges pinned against the Emsworth dam on Tuesday morning.

The Coast Guard is investigating how the barges got loose from their moorings late Friday, striking a bridge and smashing a pair of marinas. All but three of the barges were loaded with coal, fertilizer and other dry cargo. Statler said the barges broke loose “under high water conditions on the rivers, resulting in strong currents due to flooding in the area.”

Water levels on the Ohio rose very rapidly last week and then fell just as rapidly, said Matt Brown, chief of the Allegheny County Department of Emergency Services. Barge owners are well aware of the risk of high water and must constantly adjust the ropes that hold their vessels in place, he said Tuesday.

"Most of the mariners are very proactive," Brown said. “It's not very often this happens, but we know that’s when the biggest threat level is. That’s the time they’ve really got to watch, hour by hour, because you’ve got to make adjustments."

No injuries were reported.

An inspection of the Sewickley Bridge revealed no significant damage, and the bridge was reopened to traffic on Saturday,

Campbell, of Canonsburg, Pennsylvania, owns and manages more than 1,100 barges and moves about 60 million tons of dry and liquid cargo each year, according to its website.

The barge mishap took place more than two weeks after Baltimore’s Francis Scott Key Bridge collapsed after it was hit by a wayward cargo ship, killing six construction workers who plunged to their deaths.