News: Nashville District completes Wolf Creek Dam barrier wall
Story by Leon Roberts
JAMESTOWN, Ky. – Construction workers placed concrete for the last pile today, which completes the underground barrier wall and paves the way for raising the Lake Cumberland pool level. It is the last of 1,197 piles that are approximately four feet in diameter and extend 275 feet from near the top of the dam into bedrock below the foundation of the 4,000-foot-long embankment of Wolf Creek Dam.
After a successful review period, the district plans to raise Lake Cumberland in increments. The initial one will target an operating zone between elevations 700 and 705 feet or about 20 feet higher than the current range of elevation 680 to 685.
According to Bernie Kearns, materials engineering technician, more than 170 cubic yards of concrete went into the last pile and altogether the Corps placed nearly 300,000 cubic yards of concrete in building the entire barrier wall and work platform.
“That’s enough to build a sidewalk 4- or 5-feet wide from here to Washington, D.C.,” Kearns said. “That’s a lot of concrete. It’s hard to imagine.”
December 2013 is the original completion date for the barrier wall. As the project proceeded toward completion, the Corps and the contractor, Treviicos-Soletanche Joint Venture, improved efficiencies and work processes, all the while keeping job safety requirements at the forefront. As a result the Corps completed the barrier wall installation nine months ahead of schedule.
John Schnebelen, Nashville District safety officer at the project site, said to date the men and women on the construction site have accumulated more than 1.2 million hours without a lost-time accident.
“Everything just gets slowed down significantly when you have accidents on the job site,” Schnebelen said. “When you talk about production you talk about productivity and safety – they both go hand in hand.”
Wolf Creek Dam is on the Cumberland River in south central Kentucky. The lake’s huge water storage capability provides downstream communities with important flood risk reduction, and additional water resources supporting commercial navigation, water supply, water quality, hydropower, and environmental benefits.
Lake Cumberland is the largest reservoir east of the Mississippi and the ninth largest in the United States. It impounds 6,089,000 acre-feet at its maximum pool elevation of 760.
Since January 2007, the Corps has operated the reservoir at its current lower level to reduce water pressure against the dam and its limestone foundation. The barrier wall is designed to stop seepage through the karst limestone geology in the foundation of the earthen embankment section of the dam.
Bill DeBruyn, resident engineer for the Wolf Creek Dam Foundation Remediation Project, said everyone in the region is celebrating the completion of the barrier wall, which reduces the risk of a dam failure and makes communities downstream more safe.
“The main purpose of this project was to cut off the flow through the rock structure in the foundation of the dam. And by the completion of this wall we should be able to, provided we have the concurrence of the Risk Management Center, start raising the lake incrementally,” DeBruyn said.
He commended the Corps team and the contractor for working together safely to get ahead of the construction schedule and ultimately reaching this completion milestone.
“We’ve had a very good safety record – I think we’ve had two years without a lost-time injury … we’ve gained several months on the schedule right here at the very end,” DeBruyn said.
Initial planning efforts for the repair action commenced in 2004. Corps officials approved a major rehabilitation report that authorized the construction features in 2005. The $594-million project includes a significant cost-share requirement with the Southeast Power Administration, which is contributing $327 million toward the project.
Several other contracts have been completed as part of the overall project. The Corps made improvements to parking and the boat ramp at Halcomb’s Landing to accommodate logistics requirement near the work platform in 2007. Initial grouting took place from September 2006 to November 2008 and another contract took care of drilling and grouting in the dam’s plaza and gallery from August 2011 to November 2012.
A ceremonial concrete placement and public completion ceremony is scheduled at the Wolf Creek Dam work platform 10 a.m. April 19, 2013.
The public is invited to celebrate the project’s completion with the Corps, its contractor Treviicos-Soletanche Joint Venture, and other local, state and national officials expected at this event. More information will follow as the event approaches to include parking information and the agenda.