Lake Levels Won’t Be Raised By July 4th

By Bill Mardis, Commonwealth Journal, Somerset, Ky.

Jun. 25–SOMERSET — The initial grout curtain in troubled Wolf Creek Dam is nearing completion but the chances of a significant change in the level of Lake Cumberland in time for the Fourth of July weekend are next to none.

Firstly, the U.S. Army Corps of Engineers at this point has made no decision to raise the lake level. Secondly, even if such a decision were made, typical summer weather conditions would make it next to impossible to flush much water into the lake during the few short days before summer’s biggest holiday. The National Weather Service predicts a daily chance of showers and thunderstorms from midweek through the weekend and again next week, but no major rain events are in the picture.

Ed Evans, chief of public affairs for the Corps, tends to agree with that assessment. He emphasized that ” … weather is the only thing that will change the lake level.”

Corps officials have said repeatedly that the lake level will be evaluated when the initial grout curtain is completed. Accelerated grouting (pumping liquid concrete into the dam to fill cavities) has been under way for the past year and a half since the lake was lowered more than 40 feet to ease pressure on Wolf Creek Dam. The dam was classified in high risk of failure because of uncontrolled seepage through its base of limestone karst.

“We’re very close to closing the initial grout line,” Evans said Tuesday. “It’s nearing completion but not complete,” he said. The first grout curtain is one of two to be pumped into the earthen section of the dam on both sides of a planned concrete diaphragm wall.

Evans said engineers are currently looking at the grout line and other factors, apparently meaning pressure-reading devices in the dam. Corps officials have emphasized that safety is Factor No. 1 in determining the lake level. They have said time and time again during the grouting process that instrumentation indicates the dam is getting safer by the day.

The Corps Web site, last updated June 3, said the initial grout line was 87 percent complete. Evans said that’s the last completion percentage he has heard.

Corps engineers also are evaluating proposals to insert the diaphragm. David Hendrix, project manager at the U.S. Army Corps of Engineers’ Nashville District Office, told the Commonwealth Journal late last year that specifications of the new wall will have a minimum requirement of at least two feet thick. Its depth in the bedrock will range to more than 100 feet, depending on the formation of the rock.

The new diaphragm will be 4,200 feet long and extend 300 feet through the earthen section of the dam into the bedrock. The depth of the wall will vary but will be about 75 feet deeper that the wall inserted in the 1970s to halt more serious seepage discovered in the late 1960s.

The earthen section of Wolf Creek Dam is 3,940 feet long. The remaining 1,796 feet are concrete. A contract to insert the new diaphragm is expected to be let in mid-July, Corps officials said.

There is some feeling locally that raising the lake level after the July 4 holiday may be put on a back burner since traditionally the lake gradually gets lower during the dog days of late summer leading to the Labor Day weekend.

In response, Evans said ” … it won’t be put on the back burner” because engineers will continue the evaluation process. However, Evans said logic dictates it would be difficult to attain a significant rise in the lake because of late summer weather conditions.

The lake is currently 681 feet above sea level and falling slowly. This is 42 feet below pool stage and 44 feet under the tree line.

The lake at pool stage averages 90 feet deep, so at current levels the water is still about 50 feet deep. The lake covers more than 50,000 acres at pool stage and at current levels it spreads over about 37,000 acres, the third largest body of water in Kentucky.

The highest the lake has been so far this year is 695.30 at 10 p.m. April 13. Its lowest level since repairs on the dam got under way was 680.25 at 11 p.m. December 31.

The level of the lake has been lower. It dropped to 677.80 on February 9, 1977 while the original diaphragm wall was being inserted. The all-time low was 673.01 on January 1, 1954 during a severe drought four years after the lake was impounded.

The all-time high level of the lake was 751.70 at 2 a.m. May 13, 1984. The water covered picnic and camping areas at Waitsboro Recreation Area and Pulaski County Park, among other places. At current levels Pulaski County Park is high and dry.

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