Holt Lock and Dam, Cottondale, Ala., is expected to remain closed for approximately three to five months as the U.S. Army Corps of Engineers Mobile District implements repairs to the structure’s monolith. The Corps closed down the structure on June 22 as a safety precaution after increased cracks and leaks were discovered in the lock’s infrastructure.
Since the closure of the lock and dam, the Mobile District has worked closely with industry to develop both a short-term and long-term repair plan. Replacing the bulkhead of the Lock will be done in the short term, which will take three-to-five months.
For the long-term repair solution, the district will install anchors in the lock and dam to reduce pressure to the monolith bulkhead. However, the timeline for this solution has not been determined.
The timeline of three-to-five months is due to the manufacture time required to construct the 18'x36' steel enforced bulkhead that would reinforce the monolith to allow the lock to safely operate.
Ashely Ward, Holt Lock and Dam supervisor, said he started noticing changes to the dam in May when they were finishing work on repairing the Demopolis Lock and Dam, and those concerns led to the closure of Holt Lock and Dam.
“We started noticing some new cracks forming in the basement machinery room and on top of the lock wall in early May and had some increased leakage into our gallery sumps,” Ward said. “This led to increased monitoring and getting engineering involved to start looking at the cause and solutions for a repair. After more stability analysis studies were run, the decision was made to close the lock.”
The Holt Lock and Dam opened for navigation in 1966, meaning the lock has been used for 58 years. It is part of the district’s aging infrastructure, which includes its locks and dams, most of which were built in the 1950s and ’60s.
The Mobile District is evaluating the lock and assessing the full extent of the damage. After those evaluations, a plan for repairing and reopening the lock to traffic will be developed.
In May, the District completed the repair of the Demopolis Lock and Dam in Demopolis, Ala., which suffered damage to the Upper Miter Sill.
The lessons learned from the breach at Demopolis are helping the district assess how to repair Holt Lock and Dam.
“Demopolis showed us how fast something can fail without warning, and luckily, Holt started to show signs that something was moving and was able to be closed before the damage occurred,” Ward said. “We learned how critical communication around the team is with keeping all of the onsite investigations moving along with Engineering developing the repair plan and keeping transparent communication with our waterway users to keep everyone informed of the lock’s status.”
