In Apr. 19 issue, Russell County News

"Fixing the 5736-ft.-long Wolf Creek Dam in Kentucky is one of the highest priorities for the Army Corps of Engineers. Although every dam suffers a degree of seepage, Wolf Creek's limestone foundation has been dissolving at an alarming rate, a problem that was initially detected in 1968–16 years after construction was completed. When the problem was detected again in 2005, the Corps lowered Lake Cumberland and began an ambitious repair effort. But despite the ongoing construction work, the danger of collapse hasn't been significantly reduced, and probably won't be for years–the earliest possible completion date for the work is in 2012. Until then, downstream communities, including Nashville, Tenn. remain at risk." –from Popular Mechanics, May 2008

A May 2008 Popular Mechanics article addressing aging infrastructure mischaracterizes the seepage issues at Wolf Creek Dam, the U.S. Army Corps of Engineers Nashville District stated this week.

The piece, titled “10 Pieces of U.S. Infrastructure We Must Fix Now,” correctly notes Wolf Creek Dam in Russell County, as “one of the highest priorities for the Army Corps of Engineers.” The article, however, presents misconceptions of the nature of the seepage and the reduction of risk through the current repair effort.

Popular Mechanics mistakenly claims the “limestone foundation is dissolving at an alarming rate.” “The limestone is not dissolving at an alarming rate,” states Jody Stanton, Chief Geologist of the Nashville District.

According to Stanton, the cracks and caves in the limestone foundation have developed over many thousands of years and are preexisting. HE said the current seepage problem at Wolf Creek is due to water moving through those cracks and caves and washing out the clay which fills those preexisting cavities.

The article further suggests seepage at Wolf Creek Dam was not detected until 2005.

As Stanton explains, the seepage increase is being inferred from trends in instrumentation data, collected over a period of many years.

The aggressive repair work, Stanton states, “was initiated in anticipation of worsening conditions and the possibility that, undetected, more serious situations exist, not a sudden realization in 2005.”

The drawdown of Lake Cumberland in 2005 was implemented to reduce risk while construction is completed, he added.

Popular Mechanics is also in error in stating grouting operations at the project have not significantly reduced the danger of collapse, he explained. Wolf Creek Dam is stable, and instrumentation shows the foundation is improving every day, according to the Corps.

Grout is being pumped into the foundation, and according to Stanton, the “work is producing demonstrable improvements in the foundation conditions and the dam’s performance,” Stanton said.

Construction work will likely continue into 2012, as Popular Mechanics correctly states, in order to bring Wolf Creek Dam to an acceptable level of risk. However, interim risk reduction measures such as grouting and lowering Lake Cumberland have already greatly reduced the risk of a dam failure.

Stanton reminds that risk is inherent in relying on any structure, and that “managing that risk and keeping it to a tolerable level is an ongoing focus for any responsible society.”

An editor for Popular Mechanics assured a Corps spokesperson today they intended no harm with the article and were attempting to characterize the problem accurately.

The magazine welcomed a letter of clarification from the Corps, to be printed in the July issue.