For the second time since work began on building a replacement lock at the Chickamauga Dam in Chattanooga 12 years ago, a concrete batch plant has been erected along the Tennessee River to produce the tons of concrete needed to build the new chamber walls for a new and larger lock.
After heavy rains delayed work on the $758 million lock replacement project this winter, AECom contractors are again busy preparing a conveyor system to transport the concrete into the giant 600-foot by 110-foot lock chamber erected next to the existing smaller lock which is suffering from "concrete growth" in its aggregate makeup.
"You should soon start seeing some tower cranes put on the site in the next couple of months to help bring some large pieces in place for the construction of the concrete chamber walls," said Lt. Col. Cullen Jones, commander of the Nashville district of the Army Corps of Engineers. "The heavy rains did stall some of our work for a few weeks, but the good news is that we are now working with AECom (the contractor for the next $240 million phase of the project) to identify both risks and opportunities to help us get this project done quicker, on budget and with high quality."
Jones said some equipment used by the Corps at the Olmsted Lock and Dam on the Ohio River was able to be brought to the Chickamauga Lock project to help expedite the work.
Adam Walker, project manager for the Chickamauga Lock, said a 1,000-foot conveyor system to bring the concrete from the batch plant to the lock site should be in place and in operation by this summer.
"There will be three tower cranes on site — two within the coffer dam and one on the land side — to get all the equipment in the Chamber and support the building of the concrete walls," he said.
The replacement lock project, one of Chattanooga's biggest construction projects, is designed to improve river transportation and flow on the upper third of the Tennessee River by allowing riverboats to lock through the Chickamauga Lock with multiple barges at one time. Currently, boat operators have to move each barge separately through the smaller, existing lock, which was built nearly 80 years ago.
Within the new lock being built beneath the dam, a major excavation project was completed just before record rainfalls forced the Tennessee Valley Authority to open up most of the spillways at the Chickamauga Dam and raise the Tennessee River by 12 feet above its normal level for nearly a month.
Heeter GeoTechnical, which completed its excavation work on Feb. 1, dug down as much as 35 feet in the river bottom to remove more than 100,000 cubic yards of rock prepare the lock site beneath the dam.
The higher river and heavy rain filled the coffer dam, where crews have removed more than 100,000 cubic yards of dirt and rock to dig down 35 feet to the riverbed.
The rains are the latest delay in the Chickamauga Lock replacement efforts by the Corps of Engineers, which began a decade and a half ago and, due to funding delays and construction complications, has more than doubled in cost. Walker said the Corps has already spent more than $250 million on site preparation, road rerouting and construction of the coffer dam.
Contractors for the Corps previously erected a batch concrete plant near the lock project, but that plant was later relocated when funding from Congress for the Chickamauga Lock stalled and most of the money available for new locks and dams was spent for the Olmsted Lock and Dam in Ohio.
In the current fiscal year, the Corps has allocated $89.7 million for the Chickamauga project so the Corps exercised four more options on the next phases of the project in late March, Walker said.
Although no money for the Chickamauga Lock was included in President Donald Trump's original budget plan a year ago, Congress ultimately allocated the extra funding for the Chickamauga Lock this year, and the Corps estimates efficient funding next year for the replacement lock at Chickamauga could be as much as $104.3 million.
President Trump redirected $1 billion from the Corps of Engineers budget last month for border security along the Mexican-U.S. border under his emergency declaration. But the Inland Waterways Users Fund, which is jointly funded by taxpayers and the barge industry through diesel taxes and is used to fund projects like the Chickmauga Lock, was not affected by the redirection of funds under Trump's emergency order.
"None of the U.S. Army Corps of Engineers' Civil Works appropriations have been redirected for border barrier purposes," Gene Pawlik, a public affairs officer for the U.S. Army Corps of Engineers in Washington D.C., said Tuesday.
With adequate funding, the new Chickamauga lock could be finished by 2024, Jones said.
Email Dave Flessner at email@example.com or at 757-6340.