Lake will be back to normal next December
August 28, 2012 Share

Lake will be back to normal next December

Lake Cumberland will return to normal operational levels in stages when the Wolf Creek Dam Rehabilitation Project is complete in December 2013.
 
The lake will be raised in increments and each stage will be monitored, said Don Getty, manager of the $594 million repair project. The water will begin to rise when the final secant piles (50-inch overlapping holes filled with concrete) are in place and the concrete matured. “This (maturation of the final piers) shouldn’t take more than a week or so,” said Getty.
 
One thing apparently is for sure. The lake level won’t be elevated until the permanent barrier wall is in place.
 
“There is a possibility the lake won’t be at normal pool stage by Summer 2014, but it certainly will be higher than it is now,” Getty said. However, with sufficient rainfall and no issues evolving from the monitoring process, the lake could be at normal operational levels at that time, he remarked.
 
Increments – how many feet the lake will be raised for each monitoring process – have not been established at this point,” Getty said. In times past, when the Corps talked about raising the lake level, it was 10 feet at a time, but this apparently won’t necessarily apply when dam repairs are done.
 
The project manager emphasized Mother Nature will play a big role. He said normal rainfall should be sufficient to get the lake back to pool stage by the Summer 2014 recreational season. However, if there is less than normal rainfall, the lake won’t rise that rapidly.
 
An assessment of the barrier wall being formed is currently under way “ … and we hope to have that finished by the time the rehabilitation is complete,” said Getty. “Bad assessments could slow the process, but quality control issues are excellent at this point,” he added. 
 
Getty said the permanent concrete barrier wall is 80 percent complete. The permanent wall will consist of about 1,218 secant piles to protect the 4,000-foot-long earthen section of the dam. 
 
The 50-inch-diameter holes to be filled with concrete are drilled 275 feet deep from the work platform on the upstream side to the dam to about 100 feet into the limestone bedrock beneath the dam. Drilling is done through an already-installed protective concrete embankment wall to keep vibrations from adversely affecting the earthen dam.
 
Lake Cumberland has been kept about 40 feet below normal since January 2007 to ease pressure on the dam and facilitate the rehabilitation project. An outside panel of experts in 2005 declared Wolf Creek Dam in “high risk” of failure because of uncontrolled seepage.
 
Corps engineers have said the rehabilitation project now under way will permanently fix Wolf Creek Dam, plagued with seepage since the gates were initially closed in December 1950. More serious leaks, including sinkholes developing in the electrical grid area below the dam, occurred during the late 1960s. A concrete barrier wall, not long enough and not deep enough, was installed during the 1970s. 
 
The initial wall, about 40-50 feet on the downstream side of the wall being installed, remains in the dam. The new wall, along with the initial wall and the protective concrete embankment wall, effectively means the earthen section of the dam will be bolstered by three concrete walls.

By BILL MARDIS,
Editor Emeritus
Commonwealth Journal

 

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