Apr. 23—The Wilson Dam lock-gate repair project has been delayed, and local industries will have to continue contending with massive barge backlogs until the lock is fixed in early July.
The U.S. Army Corps of Engineers on Tuesday said in a press release that the schedule shift is due to a combination of weather delays, technical challenges and the sequencing of critical tasks.
The release says these factors have resulted in a three-week delay beyond an earlier mid-June estimate.
However, the Corps has completed the process of jacking both main chamber gates, exposing the cracked pintle assemblies that need to be replaced.
Heavy rains in late March elevated water levels in the Tennessee River downstream of Wilson Dam where the Corps installed a caisson, a watertight chamber used in underwater construction.
Evacuation procedures are initiated when water levels get too high so personnel and equipment can be removed in advance of any potential overtopping.
“The tailwater at Wilson Dam nearly crested the caisson several times over the last few weeks,” said Brian Mangrum, chief of the Technical Support Branch at the Corps’ Nashville District. “Because of this, we exhausted the adverse weather days we had built into our estimated timeline.”
Jeremy Nails, president of the Morgan County Economic Development Association, called the delay “definitely unfortunate, but you can’t predict the weather or other obstacles that might come up.”
Nails said dam repairs are affecting local industries’ inbound and outbound shipping on the river.
“At this point, the Corps and TVA are doing the best they can because they know how important this is to our economy,” Nails said. “I hate to hear that the schedule has been pushed back, but some things are unavoidable, especially when the dam requires a lot of the parts to be fabricated.”
Cline Jones, executive director of the Tennessee River Valley Association/Tennessee-Cumberland Waterways Council, in March said 300 barges and tows were in line waiting to get through the smaller auxiliary lock, the only one functioning while the main lock is under repair.
He said when operational, a 15-barge tow can be locked through the main Wilson Lock in 2 1/2 hours. Only one barge at a time can pass through the 100-year-old auxiliary lock and each one takes about 1 1/2 hours, so a 15-barge tow can take more than 20 hours.
“Repairing Wilson Lock is a national priority for the Corps, and we are moving as quickly as we can to get it up and running again,” Mangrum said. “However, the safety of our employees and anyone who uses the lock will always come first.”
Working through last weekend, crews at the lock jacked both land and river side gates on Sunday, exposing the damaged pintle assemblies so they can be replaced. Each gate weighs approximately 650 tons and is lifted using a series of hydraulic jacks.
“Addressing the challenges that come with maintaining infrastructure is never easy, but this team is working day and night to accomplish it,” said Lt. Col. Robert Green, commander of the Corps.
— bayne.hughes@decaturdaily.com or 256-340-2432