On May 8, 2026, the U.S. Army Corps of Engineers Nashville District terminated its lock chamber construction contract with Shimmick Construction Company, Inc. at the Chickamauga Lock Replacement Project on the Tennessee River in Chattanooga, Tennessee. It was the latest setback in a project that began in 2004, has consumed more than $569 million, and is still targeting completion in 2028 — nearly a quarter century after it started.

According to USACE's official announcement on DVIDS, the Nashville District is now "exploring all contracting options" to complete remaining lock chamber construction while maintaining the overall project timeline. The agency's stated goal remains delivering an operational navigation lock in 2028.

What Is Being Built — and Why It Matters

The new Chickamauga Lock will be 600 feet long and 110 feet wide, replacing the original 1940-era structure that measures just 360 feet by 60 feet. When complete, the new lock will handle nine jumbo barges per lockage — compared to just one in the current lock — delivering an 80% increase in navigation efficiency for commercial tows moving commodities up and down 318 miles of upstream Tennessee River waterway.

The total risk-based project cost now stands at $954.4 million at FY2023 price levels, according to USACE's Great Lakes and Ohio River Division project page. Through December 2024, approximately $569 million had been expended. The remaining work is significant.

Even before the Shimmick termination, the project had a complex multi-contract structure. In February 2026, USACE awarded the final contract — the Approach Wall and Decommissioning Contract — to C.J. Mahan Construction Company LLC of Urbancrest, Ohio, for a base contract of $192,143,924.90. That contract covers downstream approach walls, dam breaching to connect the upstream approach to the new lock, and removing the cofferdam once the new lock is operational. Under that contract, navigation traffic will transition to the new lock.

"We are proud to award this contract for this important navigation infrastructure project," said Lt. Col. Guillermo Guandique, Nashville District commander, in the February announcement. "The entire USACE team managing this project is ready to work with our contract partner and move the project to the finish line."

With the Shimmick termination, USACE now must re-procure the lock chamber work — a process that adds uncertainty to the 2028 target and will require a new contractor to pick up work that, as of February 2026, was approximately 76% complete.

A System Under Strain

The Chickamauga situation is severe, but it is not isolated. The U.S. inland waterway system — 12,000 miles of navigable waterways moving approximately 600 million tons of cargo annually — relies on locks and dams that are, in many cases, well past their designed service lives.

According to Waterways Council, Inc., the advocacy organization representing the inland marine transportation industry, active USACE construction projects underway include:

Kentucky Lock Addition Project (Tennessee River, Grand Rivers, Kentucky): A new 1,200-foot by 110-foot lock chamber is under construction by Thalle Construction under a $380 million contract for downstream monoliths, estimated for completion in May 2027. The overall Kentucky Lock project — which began more than 25 years ago — is now forecast to complete in the 2031 timeframe, with the new lock chamber operational in 2029-2030. The project is tracking at approximately 297% cost overrun against original estimates, according to Marine Link's January 2026 analysis.

Mississippi River Lock and Dam 25 (Upper Mississippi, Missouri/Illinois): A new 1,200-foot lock received $732 million through the FY22 Bipartisan Infrastructure Law. Additional funding of approximately $1.53 billion has been identified as needed to fully fund construction based on cost certifications through June 2023, per USACE's Rock Island District.

Montgomery Locks and Dam (Upper Ohio River, Pennsylvania): Active construction of lock replacement under the IIJA program. Also active: Monongahela River Locks 2-3-4 replacements, Illinois Waterway LaGrange Lock, McClellan-Kerr Arkansas River Navigation System Three Rivers Project, and others.

Funding Structure and Ongoing Challenges

Inland waterways construction projects are cost-shared between the federal general fund (65%) and the Inland Waterways Trust Fund (IWTF) (35%), which is capitalized by a 29-cent-per-gallon tax on diesel fuel used by commercial towboats. The IIJA provided $2.5 billion for seven inland waterways projects — a significant boost — but the program has historically been chronically underfunded relative to need.

According to the National Waterways Conference's February 2026 federal spotlight, FY2026 appropriations signed January 23, 2026, provided approximately $400 million for inland navigation construction — funding described as critical to keeping ongoing modernization projects on schedule. But that remains well below what a full, accelerated modernization program would require.

The USACE's own December 2025 transportation update for the Illinois DOT, obtained from the agency's public materials, lists seven active Construction Important to Shipping (CIS) projects, noting that zero non-routine packages to address backlog were funded in the FY2026 President's Budget — reflecting the depth of the maintenance gap beyond the active major construction program.

The Bigger Picture

For the construction industry, America's inland waterways represent one of the most durable long-cycle infrastructure programs in the country. Each of the major locks under construction involves multi-year concrete-intensive work, massive fabricated gate components, specialized cofferdam construction, and complex marine logistics — demanding specialty contractors and a skilled workforce with limited redundancy.

The Chickamauga contractor termination, while a setback for the project, also underscores how rare and specialized the pool of contractors capable of executing this class of work actually is. Finding a qualified contractor to complete the remaining 24% of a partially built lock chamber — with specific concrete formulations, embedded hardware, and tight tolerances already established — is not a routine procurement exercise.

USACE's goal of an operational Chickamauga lock in 2028 remains the agency's stated target. Whether re-procurement and contractor mobilization can meet that timeline will become clearer over the summer as the Corps advances its contracting strategy.

Sources

https://www.dvidshub.net/news/564829/usace-terminates-chickamauga-lock-chamber-contract
https://www.lrd.usace.army.mil/News/News-Releases/Display/Article/4406806/usace-awards-chickamauga-lock-replacement-projects-final-contract/
https://www.lrd.usace.army.mil/Missions/Projects/Article/3812399/chickamauga-lock-replacement-project/
https://www.workboat.com/army-corps-cancels-chickamauga-lock-chamber-contract
https://www.wkms.org/business-economy/2024-11-18/construction-of-massive-kentucky-lock-addition-project-hits-milestone-after-nearly-25-years
https://www.marinelink.com/news/inland-waterways-infrastructure-time-534748
https://www.mvr.usace.army.mil/about/offices/programs-and-project-management/district-projects/projects/article/3927566/navigation-and-ecosystem-sustainability-program-nesp-lock-and-dam-25-new-1200-f/
https://waterways.org/5016-2/