Dam In Distress
Published 12:00 am Saturday, June 7, 2008
GREENUP, Ky. — They’re really not as big as the Titanic. But there is something just as intimidating about looking at the miter gates at the Greenup Locks and Dam.
All that massive steel looks invincible, but it’s not, especially when it’s in use 24-7.
That’s because the steel in the gates at Greenup is no different than steel is your car. It is subject to those stresses known as wear and tear.
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“Through fatigue things start to wear out from time to time,” explains Mike Keathley of the Huntington, W.Va., District of the U.S. Army Corps of Engineers. “Every time you cycle those gates, they are subject to stresses. … After a number of cycles things start to crack. The steel corrodes. You experience problems. The emergency closures because of failed equipment on those locks, that’s an economic impact. At Greenup basically you shut the river down.”
Locks and dams
Looking down from the perspective of a riverbank, something like the beautiful Ohio may seem as deep as an ocean because the bottom cannot be seen.
But riverbeds are a notorious hodgepodge of uneven terrain with undulating degrees of slope. As the amount of precipitation varies during the different seasons, a river can have significant changes in depth.
That’s where the dams come in because without a system of dams a river could at places be too shallow for navigation.
However, with the dams come the need for the addition of locks, which allow boats to be lifted or lowered from one depth in the river or pool level to another. A lock is simply a concrete box with two miter gates at either end where the water level is raised or lowered to allow the vessel to move through the dam system.
There are 275 lock chambers on U.S. waterways operated by the Corps. Usually, they come in two sizes — 600 feet or 1,200 feet long.
At Greenup, which began operation in 1962, the smaller lock is used as an auxiliary; commercial towboats and barges usually go through the larger one, ideally in a single trip.
However, if that larger lock can’t be used, the auxiliary is called into play. But because it is half the size, that means a towboat with several barges attached often must be broken apart and moved through the locks in several trips. Then after all the barges have gone through, they must be recoupled before the tow can continue on its way.
“Trying to process through that auxiliary chamber is only half as efficient as the main chamber,” Keathley said.
In other words, a towboat with 15 barges could go through the larger lock chamber in about 45 minutes. But when it has to be broken up, it can take between two and three hours to get back into the waterway.
In November 2003 the main lock at Greenup had to be shut down for seven weeks to repair damage to its miter gates. The economic impact of that roughly two-month shut down to the navigational industry has been estimated at $13 million, Keathley said.
That figure comes from computing the hourly cost of operating tows and barges.
“Every hour he is sitting on the river is multiplied by all the towing companies,” Keathley said.
However, there is more. That figure doesn’t include hidden costs that come from the delays customers expecting a shipment on time must face. An example would be if a power plant is expecting a delivery of coal finds the shipment is held up because of a slowdown at the locks.
“Most power plants maintain a very small surplus of coal. It’s delivered on an as-needed basis,” Keathley said. “(Then) they have to find an alternate means.”
Project to expand
The Corps has in the works a project to expand the auxiliary lock at Greenup so these kinds of costly bottlenecks are eliminated.
The plan first is to enlarge the auxiliary chamber to double its current size to 1,200 feet. Then the miter gates of the larger lock will undergo extensive restoration.
“The sequence is to continue operating the main chamber while we expand the auxiliary to 1,200 feet,” he said. “Once the 1,200 feet is completed, we’ll divert the traffic to the recently expanded one while repairs are made to the miter gates.”
Currently, the project is in the design phase with the earliest possible starting date to be 2013 depending on when funding is received.
The expected price tag for the extension and the gate rehabilitation is to hit $240 million over a serious of phases over a seven-to-10 year period from start to finish.
Partial funding for the beginning phases has recently come from Rep. Charlie Wilson, who has already secured $492,000.
“This project is vitally important for the transportation of coal,” Wilson said. “It plays an integral part in insuring safe and efficient transportation and commerce along the river.”