Published: March 25, 2008 03:31 pm            

Dam's "troublesome spots" hold up decision on lake levels

Monticello — Two "really troublesome" areas in seepage-plagued Wolf Creek Dam are

requiring a "lot of extra work" and have delayed a decision on the level of

Lake Cumberland this summer.

Barney Davis, chief of the Engineering and Construction Division at the

United States Army Corps of Engineers' Nashville District, declined to

project when the lake level will be determined for the upcoming tourist

season.

However, Davis did say that "... we're not talking about months ... it

will happen quickly." Speculation that the lake level would be raised 10

feet this summer was triggered late last year in a news release from

Congressman Hal Rogers, R-Somerset.

Rogers' office announced that the level would be 690 feet above sea

level‹10 feet above the target 680‹for the 2008 tourist season.

The Corps' Nashville District, however, quickly refuted this assumption,

saying no decision had been made on the lake level. They said then, and now,

that a process would begin to determine the 2008 level when the upstream

grout line is complete.

An accelerated grouting program has been underway at the dam since

January 2007. The lake was lowered 40 feet at that time to ease pressure on

Wolf Creek Dam, classified by a panel of experts as being in high risk of

failure.

Davis, during an interview with the Common-wealth Journal, reiterated

that the Corps has a process for determining the lake level based on

"completing structural improvements and behavior of the project." Corps

engineers emphasize that the foundation of the dam is stable and improving

every day.

The first step in this process to determine the lake level begins with

completion of the upstream grout line, Davis said. "Based on the geology of

the area, we don't know how many holes we will have to drill until we get

there," Davis noted. He said the problem spots in the earthen part of the

dam are about 400 feet from the concrete section and about the midway point

of the earthen structure near the curve in the road.

Davis described the areas as "really troublesome." These problems have

pushed back completion of the upstream grout curtain. Curtains of grout, a

soupy concrete mixture pumped under pressure to fill cavities in the dam,

are planned both upstream and downstream of a diaphragm wall to be inserted

in the dam. It will be the second concrete wall, longer and deeper than a

diaphragm inserted during the 1970s.

Contractually, the upstream grout curtain was to be completed February

21. "We didn't make it," said Davis, obviously because of the troublesome

spots.

Heavy rains in the Cumberland River Basin have muddied upper reaches of

the lake and raised the level nearly 10 feet above the 680-foot target

during this phase of the rehabilitation. Water is being released through the

dam at a rate of 13,740 cubic feet per second.

Wolf Creek Dam has been plagued with seepage almost since its

impoundment in 1951. Sinkholes developed in the vicinity of the electrical

grid below the dam in the late 1960s and muddy water was observed in the

tailrace. The problem then, engineers say, was much worse that the current

seepage problem, first announced in August 2005.

The rehabilitation program currently underway is scheduled to take up to

seven years at an estimated cost of $309 million.

        

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