Coast Guard Admiral Tours Chickamauga Lock

The U.S. Coast Guard’s incoming assistant commandant toured Chickamauga Lock to see where physical expansion of concrete causes structural deficiencies, and observe how ongoing excavation of the riverbed is making way for construction of a new navigation lock to improve access to the upper reaches of the Tennessee River Basin.

Vice Adm. Charles Ray, deputy commandant for Operations, began the day as reviewing officer for the Armed Forces Day Parade in downtown Chattanooga, which highlighted the U.S.

Coast Guard. After saluting the area’s vets, he met with U.S. Army Corps of Engineers Nashville District and Tennessee Valley Authority officials at the lock, which is located at Tennessee River mile 471.

“I took this opportunity to meet with the Corps of Engineers because the movement of commerce is a really important mission for the Coast Guard,” Vice Adm. Ray said.

The Chickamauga Lock Replacement Project is the fourth highest priority inland navigation project in the Corps of Engineers. The Nashville District is constructing the new 110-foot by 600-foot lock to replace the existing 60-foot by 360-foot lock, which is owned by TVA, but operated and maintained by the Corps of Engineers. The existing lock is experiencing concrete growth caused by a reaction between the alkali in the cement and the aggregate. Even with significant maintenance efforts, this expansion threatens the lock’s structural integrity and limits its lifespan.

Tommy Long, Nashville District’s resident engineer for the project, accompanied the admiral to a vantage point on the dam to show him where the Corps of Engineers is blasting daily to remove 100,000 cubic yards of rock from the riverbed. There have been about 130 blasts so far with about a third of the excavation work completed.

“I updated the admiral on past construction and ongoing excavation work, and talked about the cooperation we had with the Coast Guard years ago with the coffer dam,” Mr. Long said. “We also discussed the funding issues that have slowed down construction in previous years, and recent efforts to get the project on track with a good path forward.”

Approximately one million tons of commodities lock through the existing lock annually, but the long term forecast for the larger replacement lock is upwards of four million tons per year. Once completed, the new lock will improve locking efficiency and is estimated to generate $48.3 million in average annual benefits to the nation.

The existing lock passes only one barge per lockage, but the new lock will be capable of passing nine barges per lockage, resulting in an 80 percent reduction in commercial transit times. About 3,000 recreational vessels also pass through annually, the most of any lock on the Tennessee River.

There are 318 miles of navigable waterway upstream of Chickamauga Lock used to transport materials to and from industries, TVA facilities and the Department of Energy at Oak Ridge. The concrete aggregate problem could eventually result in the closure of the existing lock, which would land lock the upper reaches of the waterway if the new lock is not yet completed.

Lockmaster Cory Richardson said the admiral seemed interested in the concrete growth, the monitoring systems for the old lock, and the process of blasting out the bedrock for the new lock.

“I showed him the concrete cracking on the old lock, the inverted pendulum system we use to monitor lock wall movement, and the lower lock gates,” Mr. Richardson said.

The admiral said the Coast Guard’s partnership with the Corps of Engineers is important and visits like this help him understand the project and how it affects navigation, so he can advocate if necessary.

Lt. Col. Cullen Jones, Nashville District commander, said he talked with the admiral about the critical nature of the lock replacement and necessity to replace it as quickly as possible considering how it will speed navigation, improve economic development opportunities, and enhance national security along the Tennessee River.

“Across the entire Great Lakes and Ohio River Division, the partnership we have with the Coast Guard on the water and providing them critical engineering services continues to grow and is strengthened by leader engagements such as this visit,” Lt. Col. Jones said.

He added that he really valued the interaction with Admiral Ray given how the district and Coast Guard routinely coordinate to improve emergency readiness in the Cumberland and Tennessee River Basins.