By BILL MARDIS, Editor Emeritus
Commonwealth Journal
Somerset —
Cracks do exist in the U.S. 127 surface atop Wolf Creek Dam and the separations are getting wider. However, the U.S. Army Corps of Engineers emphasized Friday that no new cracks have developed in the roadway.Some news organizations apparently misunderstood the situation and reported new cracks in the road. This is inaccurate; the Corps is monitoring existing cracks, not new cracks, Corps officials said Friday.
The story in the Commonwealth Journal (Wednesday, June 23) about the widening cracks atop the dam was based on responses by Allison Jarrett, public affairs specialist for the Corps, to questions submitted by the Commonwealth Journal about conditions at the dam. Jarrett emphasized the story in the Somerset newspaper was absolutely accurate ... but it was “picked up” by some other news organizations and “new cracks” were added, she said.In a clarification sent to news organizations Friday the Corps said recent reports that new cracks have suddenly appeared on the roadway over Wolf Creek Dam are inaccurate. The Corps has been monitoring these cracks for several years, and widening of the cracks was one of the reasons work was suspended in March in the 600-foot section of the dam nearest the concrete embankment.
“We observed several months ago that some of these cracks had widened about one-half inch to an inch since the beginning of the year,” explained Mike Zoccola, chief of Civil Design for the Corps’ Nashville District. “This movement and other small changes in instrumentation readings prompted the partial work suspension in March.“As a precautionary measure, we have suspended construction in Critical Area 1 while we evaluate the most recent monitoring and instrumentation data,” stated Barney Davis, chief of Engineering and Construction Division for the Nashville District, in a March 10 news release from the Corps. Critical Area 1 is the portion of the dam where the earthen embankment ties into the concrete section and has been the major source of seepage during the history of the dam’s operation.
“This evaluation continues with a focus on the cracks in the roadway over the dam. The purpose of the evaluation at this point is to determine what is causing those cracks to widen,” said Zoccola. “They could be caused by something as innocuous as weather or temperature, or possibly changes in lake levels, or they could be indicative of deeper shifting of the embankment.”Zoccola emphasized that the dam is not in imminent danger.”We’re being overly cautious,” he said. “We are installing more instruments and taking the time to confirm the movements are not signs of deeper shifting of the embankment before we proceed with our construction efforts.”
The evaluation and testing will also show more conclusively whether construction work in Critical Area 1 was contributing to the movement. Results of the tests are expected in August, at which time the Corps will be able to determine the appropriate way to proceed with treating, or fixing Critical Area 1.“We want to ensure that our treatment methods are effective and that we can safely install the remainder of the concrete barrier wall,” said Davis.
Jarrett told the Commonwealth Journal Tuesday that the suspension of work in the 600-foot critical area has been extended at least until August. Although engineers are not 100 percent sure, Jarrett said it is “highly likely” that the problems will push back the projected December 2012 completion date of the rehabilitation project.She also said there are no plans to lower the current level of Lake Cumberland. The lake has been held about 40 feet below normal since January 2007 to ease pressure on the troubled dam and facilitate repairs.
A concrete diaphragm wall, longer and deeper than a similar wall installed in the 1970s, is currently being inserted in the 4,000-foot earthen section of the dam. Major rehabilitation of the structure is being done after an outside panel of experts declared the dam in high risk of failure.
