Army Corp: Demopolis Lock should reopen in May

Army Corp of Engineers says they are on track to reopen the Demopolis Lock on the Tombigbee River by the end of May.  

Steven Beams of the Corp said they have removed 1,000 tons of concrete that broke off and fell from the sill to the bottom of the chamber in January, causing water to fill up the lower chamber and prevent the dam to lock. This prompted closure of the lock to boat traffic that uses the Tombigbee to get to Mobile so that crews can make the major repairs needed. 

In weekly conference calls, businesses and industries that use the Tombigbee and Black Warrior Rivers have said they are losing millions of dollars a month while the lock is closed. 

Crews have been working on a five-to-10-year band-aid solution to get the lock reopened, Beams said. 

“We’re doing our best to affect the most substantial repair in the most efficient amount of time,” Beams told the Black Belt News Network. “We know our users need it open, so we are going as fast as efficiently possible and still have a good product.” 

Beams said concrete forms have been installed in the lock chamber and the pouring of new concrete has started as repairs continue. 

The corpwasn’t aware of how serious the debris problem was at first, he said.  

“We had to bring in a big A frame (crane) from New Orleans,” he said. “It’s the same kind of machinery that they’ve got in Baltimore trying to get the (damaged Francis Scott Key) bridge out of the waterway.”  

High waters from the recent rains may slow progress, but Beams said the first concrete pour was last week, a week ahead of schedule. 

“There is about three days between each concrete pour, and there are seven total, so we’ve got about 15 to 20 days of concrete pouring,” Beams said. 

A research group out of Vicksburg, Mississippi, has taken core samples from the original concrete in the debris pile to locate a cause for the collapse. The corp has also performed strength testing on the concrete.  

“Initial opinions are that there is no apparent smoking gun in the debris piles,” Beams said. “So whatever it is is deep down in the concrete somewhere.” 

The repairs being made are being treated as a short-term fix of five to 10 years,” he added, to buy the time needed to get money appropriated by the government for a total replacement. 

Locks are designed to last 50 years, but Demopolis’ lock is 70 years old. 

“So she’s made it a little bit past her expected replacement life,” he said. 

Concrete science has improved, however, so this repair could last longer, Beams said. 

After the repair, there will be periodic checks. In 2027, the Corp of Engineers is scheduled to close the lock to install new lower miter gates. “We’ll have a full dewatering then. That will give us a chance to see how this repair is holding up,” he added.