The U.S. Army Corps of Engineers suspended repair work Wednesday on a critical area of Wolf Creek Dam at Lake Cumberland because sensors picked up movement near the dam's foundation.
The movement is near where grout was being injected around a cave feature below the water's surface, said Project Manager David Hendrix. He said analysis of instruments, drilling and grouting data and the dam's stability could take four to six weeks, and after that, the Corps would decide how and when to proceed with repair work.
Work was halted on a 600-foot "critical area 1" where the earthen embankment meets the concrete dam, but work on non-critical areas will continue, officials said. The dam is 4,400 feet long, and the rehabilitation project is expected to cost $584 million.
The project schedule would have had work on the largest critical part of the dam completed by the 2011 recreational season, Hendrix said.
"With these delays, that's highly unlikely," he said.
The Corps decided in 2007 to lower the water level in Lake Cumberland from about 720 feet to less than 680 feet.
The lake's operation and water levels are expected to be unchanged by Wednesday's work suspension, Corps officials said.
"You know, safety has to be the No. 1 priority," said J.D. Hamilton, owner of Lee's Ford Resort Marina and president of the Lake Cumberland Association. "There's plenty of water to recreate on. If they're not going to lower any more ... I think people have gotten used to it."
Hamilton said delays in the project are a worry, but tourism is still healthy on the lake.
Wolf Creek Dam was built in terrain that has caves and voids in the rock under the earthen part of the mile-long structure. Water is seeping through, creating a risk of failure.
The Corps started emergency repairs in 2007, injecting grout into the foundation of the dam to stem leaks. That has helped the structural integrity, and the dam is safer now than it was, agency officials have said.
However, the grout didn't work in the area where the earthen and concrete sections of the dam meet.
A contractor is in the early stages of a $341 million project to build a massive concrete wall inside the earthen part of the dam, deep into the rock foundation, to cut off leaks.