Engineers: Major Tennessee dam at "high likelihood" of failure

By ANNE PAINE Staff Writer - THE TENNESSEAN

A huge dam on the Cumberland River upstream of Nashville has a "very high likelihood" of breaking and flooding within five years if the lake behind it isn't lowered and repair work isn't done, according to a panel of engineers.

Wolf Creek Dam, the aging, leaking concrete-and-earth barrier that forms Kentucky's Lake Cumberland, is "critically near failure condition," the independent engineers reported to the federal government. Their report was made public Tuesday by the federal agency that runs the dam.

More than $3.4 billion in damage could be done if the dam broke and sent torrents of water down the Cumberland.

If Wolf Creek Dam failed, much of downtown Nashville would be flooded. Parts of the city and communities all along the river, such as Gallatin, would be hit with water, mud and the debris of houses, vehicles and anything else picked up along the way.

Mary Lynn Gillingham, whose Madison home is along the Cumberland River, is among those who read the report Tuesday and thinks the federal government needs to do more to protect those downstream.

Recalling how the spring rains in 1975 brought 6 feet of water into her house and flooded the homes of many other Nashvillians, Gillingham said she was "really disturbed" that the water level in Lake Cumberland isn't being lowered even further to relieve the stress on the dam.

Corps says fixes in works

The U.S. Army Corps of Engineers, which runs the dam, began millions of dollars' worth of emergency repair work earlier this year to shore up the 55-year-old structure. The Corps has also let millions of gallons of water flow out of the dam and into the river to lower the lake's water level ? a move that marinas and other businesses in that part of Kentucky have fought.

Because of those initial steps, key fixes that were called for in the report released Tuesday are already being worked on, Corps officials said.

"Many of the findings and recommendations are already being acted upon," Steve Stockton, the Corps' deputy director of civil works, said in a teleconference Tuesday.

According to the report, the dam, which was built to control flooding and bring electricity to rural Kentucky, effectively has come to the end of its useful life. And while the dam could fail in five years if something isn't done, fixing it may take seven years.

Panel says action urgent

Pictures in the report show where large wet spots have formed on the ground ? a sign that water from the lake is seeping past the dam. A chart shows that 37 wet spots were found in 2004.

The report was done by a panel of six engineers who were called in by the Corps for independent advice on the aging dam in the wake of the disaster in New Orleans after Hurricane Katrina.

Lake Cumberland will remain 40 feet below its usual summer level, as the Corps tries to keep pressure off the dam. However, the report said the level should be dropped an additional 40-50 feet.

The panel of independent engineers has backed off that. Keith Ferguson, an Colorado engineer who was vice chairman of the group, said the panel is "comfortable" with the existing water level. And Eric Halprin, a Corps official, said a lower water level would cut off public water supplies for 200,000 people.

Along with lowering the lake level, the Corps is well into the process of drilling down to find openings in the limestone below the dam and filling them with a concrete-like mix. Corps spokes man Bill Peoples said workers will meet the panel's May 30 deadline to finish filling in the most critical areas.

"The Panel cannot overemphasize the urgency of this action," combined with dropping the water level, according to the report.

Dam nearly failed in '68

This is not the first time Wolf Creek Dam has been in trouble. It was close to failure in 1968. The structure was completed in the early 1950s using techniques that were then standard for building over limestone foundations.

Those foundations tend to be riddled with holes through which water moves, wearing away more limestone and making cracks and holes larger.

The Corps filled in holes, much as it is doing today, and in the 1970s a wall was installed in two sections as part of the dam to stop water movement.

The walls, limited by technology at the time and "economic constraints," weren't large enough, and water has made its way around, according to the report.

More than $300 million in rehab work using better techniques and a larger wall is planned now and the situation is under much closer scrutiny, officials say.

Still, the panel says another dam, one more appropriate for the limestone terrain, may have to be built to replace this one.

A study on that could take up to three months, but won't interfere with current work.