Tennessee River locking operations keep America's economy in ship shape

U.S. Army Corps of Engineers, Nashville District
Story by David Wheeler

Date: 10.25.2011
Posted: 10.25.2011 17:23
News ID: 79004
Tennessee River locking operations keep America's economy in ship shape

NASHVILLE, Tenn. – There are nine locks on the Tennessee River that the Nashville District operates, but there are four that are crucial to day-to-day commerce of the United States in Northern Alabama and Southwest Tennessee. Operators at the Pickwick, Wilson, Wheeler and Guntersville Locks move tons of cargo through their locks on a daily basis.

The Nashville District operates and maintains 1,175 commercially navigable river miles, which is almost 10 percent of 12,000 total miles nationwide that the U.S. Army Corps of Engineers maintains.

The Tennessee-Cumberland Rivers System is a major part of the nationwide network of waterways. The Tennessee River is joined with the Cumberland by the Ohio River and the Barkley Canal. These two waterways are operated as a unit. They link communities and industry in the Tennessee River Valleys with our nationwide system of waterways and ports.

Jim Davis, Nashville District operations manager, said the ports along the Tennessee River support industry and the Decatur, Ala., port is among the busiest. The cargo traffic makes the navigation mission for the district very important to the nation, he said.

“The ports handle everything from chemicals and grain to rocket components for use in the nation’s space program,” Davis said. “Waterways transportation benefits the environment. It reduces fuel consumption, air pollution, wear and tear on highways and bridges, and make the roads safer by keeping more trucks off the highways. The locks and the cargo that passes thru provide employment for hundreds of people. I have worked on the river a long time and have seen everything lock thru from canoes to ocean going vessels.”

Inland waterway transportation of freight is considered the safest, least polluting, and most cost efficient of all freight transportation in the United States. Waterway transportation of freight is more than twice as energy efficient as rail transportation and eight times as efficient as truck transportation.

In addition to commerce a number of privately owned boats move through the locks enjoying the fantastic recreational advantages of the Tennessee River.

“Within the last year, we have moved approximately 20,000 waterborne crafts and more than 34 million tons of cargo through our locks,” said Donnie Damron, lock master at Pickwick lock. “Our locks are open for use by recreational and commercial vessels 24 hours a day, seven days a week, and 365 days a year.”

A principal value of the inland waterways is their ability to efficiently convey large volumes of bulk commodities moving long distances. Towboats push barges lashed together to form a "tow." A 15-barge tow is common on the larger rivers with locks, such as the Tennessee River.

"The Pickwick Lock is the largest of the four operated here in this region. Our main lock is 110 feet wide by 1000 feet long," said Damron. "The norm is 110 feet by 600 feet in length." The extra length allows Damron and his team to move larger tows through, which reduces the number of lockages. A process where the tug literally has to disconnect a number of the attached barges from their tow; set those barges aside and move the maximum allowable amount through the lock, once those barges are moved through the lock the towboat returns back to the top and moves the remainder through the lock.

Such tows are an extremely efficient mode of transportation, moving about 22,500 tons of cargo as a single unit. A single 15-barge tow is equivalent to about 225 railroad cars or 870 tractor-trailer trucks. If the cargo transported on the inland waterways each year had to be moved by another mode, it would take an additional 6.3 million rail cars or 25.2 million trucks to carry the load.

Most freight consists of dry bulk cargo and is carried aboard barges known as hoppers. This includes freight such as coal, finished steel or its ingredients, grain, sand or gravel, or similar materials. Petroleum products, which account for about 40 percent of the inland waterways cargo, are carried in tank barges. The largest ocean-going tank barges used on the Gulf and Atlantic Intracoastal Waterways can carry as many as 3 million barrels of oil at full capacity.