Commonwealth Journal

May 2, 2013

Corps no longer has fingers crossed about dam

By BILL MARDIS, Editor Emeritus
Commonwealth Journal

Somerset —

After nine long years of worry, engineers at the U.S. Army Corps of Engineers’ Nashville District say their fingers are no longer crossed.
“I uncrossed my fingers March 6,” said Don Getty, manager of the $594 million Wolf Creek Dam Rehabilitation Project. That was when the last pile was poured to complete a 4,000-foot-long permanent concrete barrier wall through the earthen section of Wolf Creek Dam.
Throughout the long, tedious and sometimes dangerous repair of the dam, engineers qualified every optimistic report with “We’ve got our fingers crossed.” The project was of a scope never done in the world.
Residents of nervous communities along the Cumberland River below the dam were supplied with NOAA radios on which would be broadcast warnings in case of a breach in the dam. At least once, public safety officials were put on alert when drilling caused material movement in the most critical area near where the earthen section of the dam joins the concrete monolith.
Rehabilitation of the dam is finished. Completion of the massive job was celebrated April 19. Wolf Creek Dam is safe and Lake Cumberland remains in our future.
Wolf Creek Dam is still the most monitored dam in the world. However, on-site monitoring has decreased somewhat from 24 hours a day to 20 hours a day, Getty said.
The dam is still monitored electronically around the clock. Getty says about 100 instruments in the dam would alert Nashville District headquarters by telephone and e-mail in case of an abnormal reading.
Wolf Creek Dam has a troubled history. Tensions mounted in 2005 when an independent panel of engineers declared the mile-long structure in high risk of failure. The dam, created atop porous limestone rock, has leaked since the gates were closed in December 1950. 
However, the seepage became increasingly uncontrollable and on August 15, 2005, the Corps announced publicly that a complete rehabilitation of the structure was necessary. 
Lake Cumberland in January 2007 was lowered 40 feet below its normal operational level to ease pressure on the structure and facilitate repairs.
A contract was let in July 2008 to build a concrete barrier wall at least two feet in width and extending 275 feet from a work platform on the upstream side of the dam to about 100 feet into the limestone base. 
The level of Lake Cumberland on January 23 was OK’d to rise 20 feet, beginning the first of April. The water has reached that level, even above, earlier than expected.
Getty said in case of heavy rains, the lake level will be drawn down as downstream conditions permit to maintain the 705-level target. He pointed out the importance of flood-control efforts on both the Cumberland and Tennessee rivers.
The major rehabilitation of Wolf Creek Dam is considered a new dam effect. Corps policy is to allow the lake to return to its normal level in increments, not all at once.
This coming December, and for Summer 2014, the lake will return to its historical operational level at 723 feet, or tree line.