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Aging locks on Tennessee River get poor grades

Aging locks on Tennessee River get poor grades

Posted: Wednesday, May 20, 2009 8:01 pm
By: AP


CHATTANOOGA (AP) — If things go right, it takes four or five days for Mark Mayfield’s tow boats to push barges of salt, gypsum or grain for chicken feed from Cairo, Ill., to Chattanooga, about 511 miles.

If things go wrong, as they occasionally do with the 50-, 60- and 70-year-old locks on the Tennessee River, the delivery time can double, Mayfield said.

“The chickens might be hungry,” he said.

Mayfield, the general manager for Paducah, Ky.-based Tennessee Valley Towing, said some of the locks, which allow vessels to pass through dams, were built when ships were smaller. In today’s world, that means modern tow boats must break up their loads and push one barge at a time through the system.

“It just takes forever if you have to do it one boat at a time,” he said.

Some of Mayfield’s daily obstacles were highlighted in the recent Infrastructure Report Card put out by the Tennessee section of the American Society of Civil Engineers.

The report gave Tennessee’s navigable waterways a C- grade. Without “near-term solutions” to overhaul the river transportation system, “waterborne commerce will struggle to survive,” the report states.

The group cited aging infrastructure, unscheduled closures, inadequate lock capacity, increased demand and inadequate funding as key factors for the grade, which took into account locks and channels on portions of the Tennessee, Cumberland and Mississippi rivers.

“They’re all at or beyond their design life,” said Charles Smith, an ASCE member who helped compile the waterways portion of the report.

Chickamauga, Nickajack and Watts Bar locks received grades of D, B, and C, respectively, in the report.

“I would say that’s a pretty fair assessment,” said Jeff Ross, chief of the Corps’ navigation branch for the Nashville district.

Some of the data used for the report’s navigable waters assessment came from government reports compiled before the Corps of Engineers began a $374 million project to build a new, larger lock chamber in the Chickamauga Dam.

The report cites the ongoing lock replacement, and state and federal officials hope the new lock, expected to open in 2013 or 2014, will improve future assessments.

Chickamauga’s original lock was the state’s second oldest lock, completed in 1940. Pickwick Lock, Tennessee’s oldest, saw a larger lock installed in 1980.

The average age of the locks is more than 53 years, and most were built with an expected lifespan of 50 years.

The report states that 34.6 million tons of freight passed through the locks in 2002, and waterborne freight is expected to increase to 57.5 million tons by 2035.

“As our infrastructure ages … something’s got to be done,” said Monica Sartain, an ASCE member who helped assemble the report.

While the Tennessee Valley Authority maintains the dams, the locks are managed by the Army Corps of Engineers. Ross said the Chickamauga Dam probably brought down the whole system’s score, calling it “the worst I have.”

The dam’s lock chamber measures 60 feet by 360 feet, which “doesn’t cut it anymore,” Mayfield said. Traffic can back up as barges are pushed through individually, he said. The backups cost clients about $400 an hour to pay his crew, not to mention the effects they have on production schedules, he said. 

“It’s no different than going from two lanes down to one lane on the interstate and everyone has to get in line to squeeze through,” he said.

Additionally, a chemical reaction — known as alkali aggregate reaction — between the river water and the rock in the lock walls has caused the walls to expand and shift, causing mechanical problems with the lock doors, Ross explained.

He said the Chickamauga lock is under an “aggressive” inspection and maintenance program.

Smith said his group compiled the report to raise awareness of infrastructure deficiencies, and its members agreed that locks are easy for people to overlook.

“It’s one of those things that, while it’s working, you don’t really think about it, but if it wasn’t, you’d feel it,” he said.


Information from: Chattanooga Times Free Press,
Published in The Messenger 5.19.09

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