Oakland, Calif.-based Shimmick Construction is the prime contractor to build the new 110-ft.-by-600-ft. lock chamber on the Tennessee River below the Chickamauga Dam. (Shimmick Construction photo)
A project to build a larger replacement lock at the Chickamauga Dam, first envisioned almost two decades ago, was projected at the time to cost less than $300 million and provide a quicker and more reliable water passageway on the Tennessee River near Chattanooga by 2020.
But with congressional funding delays, pandemic-related problems with supplies and labor, and "concrete growth" in the existing lock chamber, the expense of one of Chattanooga's costliest building projects has jumped more than threefold and been delayed by nearly a decade from the original projections.
The Chattanooga Times Free Press reported April 29 that the U.S. Army Corps of Engineers (USACE) told the Inland Waterways User Board (IWUB) earlier in the month that it estimates the total cost of replacing Chickamauga Lock has swelled to $954.4 million, up from the previous estimate of $757 million.
Although the USACE earlier said the project was fully funded, completing the new lock is now projected to need more money in future years from the Inland Waterways Trust Fund (IWTF), which pays for all lock and dam projects in the United States.
In a presentation to the IWUB meeting on April 13 in Pittsburgh, Pa., Kevin Jasper, the project manager of the new Chickamauga Lock, explained that the construction of the replacement lock "is significantly behind" the original projected completion in November, and efforts to speed the work have been unsuccessful.
Oakland, Calif.-based Shimmick Construction is the prime contractor to build the new 110-ft.-by-600-ft. lock chamber on the Tennessee River below the Chickamauga Dam. The new and bigger lock will replace the smaller lock that was built when the dam was first completed in 1940. When finished, the replacement lock will be able to handle nine times as many barges at one time to help speed river shipments in the region.
But Shimmick officials said the cost of their original $240 million project should be increased and more time given for completion due to delays and costs caused by COVID-19, material inflation, tight labor markets and supply delivery challenges.
Last year, the contractor requested an added $96.3 million and 590 days to complete its work, according to Stephanie Hall, deputy district engineer for the USACE's Nashville engineering district.
"The increased cost for the project is a combination of several factors to include recent project delays, changes in site conditions, design enhancements, and the overall inflation factor associated with labor and material in today's economy," noted Jasper, the interim project office chief of USACE's Nashville District, in a statement.
He added that Shimmick expects to complete its work in August 2025, and the USACE projects the overall project will be completed in either 2028 or 2029.
"An additional $237 million is required to fully fund the project," Jasper told the IWUB. "Current market conditions, extended project duration and increased inflationary rates will have impacts on required cost to complete the project."
Although work continues on the lock project, the USACE decided against distributing any new funds for more building contracts in the current fiscal year while it reassessed its cost and completion schedule, the Chattanooga news source noted.
Earlier this year, Jasper, in a statement, assured those using the Chickamauga Lock, "The lack of funding this year will not impact ongoing work on the replacement lock."
Replacement to Overcome ‘Poor Geology'
According to the Times Free Press, he noted the new lock is required due to problems with "concrete growth" in the current 83-year-old lock, "which threatens the stability and operability of the existing lock."
The upstream approach wall above the dam, originally planned to be completed by May 2024, is only 12 percent completed. "Poor geology" has required revisions to planned foundation elevations, and the contractor has submitted a cost adjustment for redesign of the drill shafts.
To build the new replacement lock, Shimmick is excavating 9,900 cu. yds. of rock, demolishing approximately 3,600 cu. yds. of existing reinforced concrete spillway, and installing 43 reinforced concrete drilled shafts, the Times Free Press reported.
The project also includes the construction of a new operations building and gate control shelters, the installation of electrical and mechanical systems to support the lock and operations building, and the operation and maintenance of the automated instrumentation system and dry commissioning of the lock.
The conveyor system Shimmick developed delivers concrete overland and over the existing lock to prevent any disruptions to lock operations.
"We are exceptionally proud to work on this important project for the U.S. Army Corps of Engineers — a project that will benefit the region now and for years to come — and are dedicated to delivering quality work that aligns with our commitment to providing the absolute best service and support to the communities we serve," Shimmick spokeswoman Clara Marshall said in a statement.
Better Lock Means More Efficient River Transport
The Tennessee Valley Authority (TVA), which was created in 1933 to harness the power and navigation of the Tennessee River, originally built the Chickamauga Dam and Lock using nearby rock aggregate that has since developed some structural problems.
The Chickamauga Dam remains a TVA project, but the Chickamauga Lock is maintained and operated by the USACE and is funded with both congressional appropriations and the proceeds from diesel taxes paid by river barges on America's inland waterways.
About 1 million tons of freight a year is moved through the gateway, and the new lock is projected to reduce commercial transit times by 80 percent, according to the USACE. The Chickamauga Lock also is the most active lock on the Tennessee River for recreational vessels, with more than 3,500 boat lockages each year.
Cline Jones, the executive director of the Tennessee River Valley Association, said the barge industry was "surprised" by the size of the cost increases for the Chickamauga Lock replacement. But Jones, who has advocated for the new lock for more than a decade, insists the investment will pay off.
"This is certainly a worthwhile project with over 319 miles of navigable river above the Chick Lock, including major facilities in Oak Ridge and nuclear plants at Sequoyah and Watts Bar that depend upon the river," Jones said in an April 27 phone interview with the Chattanooga newspaper. "Some products can only be moved by water, and they can't be shipped by rail or highway. This is still very important to this region and to the country."
He added that a bigger lock will help accommodate more and faster shipments of goods on the important Tennessee River inland waterway, one of the most efficient means of transporting heavy commodities and equipment in the country.
The USACE projects the lock helps keep up to 150,000 trucks off nearby Interstate 75 and lowers the transportation costs for many regional companies.
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