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Barrier Wall - Feb. 14, 2014

First Bite - July 11, 2012

Drilling - March 14, 2012

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Center Hill Safety Rehabilitation Project Updates

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Center Hill Dam rehabilitation continues with barrier wall installation

LANCASTER, Tenn. (Feb. 14, 2014) - The U.S. Army Corps of Engineers Nashville District’s ongoing foundation rehabilitation project at Center Hill Dam is making progress as work crews continue to drill deep into the main dam earthen embankment to install a subsurface concrete wall. The current efforts are the second of three major contracts from 2008 to 2017 that comprise ongoing efforts to rehabilitate Center Hill Dam.

According to construction resident engineer Bill Debruyn, the problems stem from the karst limestone foundation and from the standard foundation preparation practices of the early 1940’s. The foundations of the two large earthen embankments, the main dam and a smaller saddle dam, are the focus of the multi-year project. The goal is to prevent foundation seepage from potentially harming the embankments.

Today’s technology makes it possible for work crews to make the necessary repairs deep in the foundation.

“Construction is going very well and the weather is cooperating with no major delays,” said Debruyn.

Despite the arrival of cold weather and bone-chilling temperatures, workers from the Bauer Foundation Corporation are making strides at the project site located in Lancaster, Tenn., on the Caney Fork River.

According to Debruyn, an encasement concrete wall, the first major structure, is near completion. The encasement wall is made of 10’x6’ overlapping rectangular columns into the earthen portion of the dam down to the rock foundation.

“Bauer is using custom built state-of-the-art equipment to excavate vertical columns, held open with continuously circulating slurry mix,” said Debruyn. Made primarily of clay and water the slurry not only supports the hole but transports the cuttings to the surface for removal. The slurry in each encasement wall column is then replaced with concrete. The columns overlap to form a long continuous concrete wall which protects the earthen embankment while the smaller and deeper barrier wall is similarly constructed.

“Beginning in March the barrier wall will be built through the encasement wall up to three hundred feet below the top of the dam through the karst rock ending in the solid rock layers,” said Center Hill project manager Linda Adcock.

Adcock said the barrier wall is a permanent seepage barrier and is planned to be completed in the summer of 2015.

A report is undergoing final approvals to implement the best repair plan for the earthen saddle dam. A concrete berm is planned downstream of the saddle dam from 2015 to 2017 as the final major rehabilitation phase of construction.

The Corps currently manages Center Hill Lake levels targeting a summer high of 630 feet above mean sea level and a winter pool of about 620 feet; however, day to day lake levels are highly dependent on the weather. These target elevations are 10-15 feet lower than normal and are part of risk management until the repairs are complete in late 2017.

Center Hill Dam is one of the multipurpose projects that make up the Corps of Engineers’ system for development of the water resources of the Cumberland River Basin. This system is an important part of a larger plan of development for the Ohio and Mississippi Rivers. The dam controls the runoff from a drainage area of 2,174 square miles.

As a major unit in the system, Center Hill Dam and Lake function to control the floodwaters of the Caney Fork River and contribute to the reduction of flood levels at municipal, industrial and agricultural areas along the Cumberland, lower Ohio and Mississippi Rivers.

Highway 96/141 which routes traffic over Center Hill Dam is a heavily traveled road and is now restricted to one lane. The restriction is required to support the construction on the project and installation of the foundation barrier wall. During the two-year duration of construction at the site, one lane of Highway 96 will be closed and an automated traffic control system will safely manage vehicles across the dam. Debruyn said the maximum expected wait time is five minutes.

To read more on Center Hill Dam, the seepage problem, the fix and project updates visit the Nashville District webpage at http://www.lrn.usace.army.mil/CenterHill. For more information about the U.S. Army Corps of Engineers Nashville District, visit the district’s website at www.lrn.usace.army.mil, on Facebook for updates at http://www.facebook.com/nashvillecorps and http://www.facebook.com/centerhilllake, and on Twitter at http://www.twitter.com/nashvillecorps.

 

U.S. Army Corps of Engineers awards Center Hill Dam barrier wall construction contract

NASHVILLE, Tenn. (Sept. 22, 2011) — The U.S. Army Corps of Engineers, Nashville District announced today the award of a $106 million contract to Bauer Foundation Corporation to install a barrier wall at Center Hill Dam, which was officially awarded late yesterday.

To see the Federal Business Opportunities contract award announcement for this project click here.

"This important construction will provide a barrier to protect the earthen portion of the main dam from seepage problems. The barrier will significantly improve the long-term reliability of the dam and public safety" said Project Manager Linda Adcock.

Most of the construction will be accomplished below ground and requires specialized equipment as well as close monitoring.

The main components of work are:

• Enlarge a work surface along the upstream (lake) side of the main dam earthen embankment

• Construct approximately 200,000 square feet of concrete panels and columns in two phases through the embankment extending downward 120 feet into foundation rock to form a minimum 2-foot thick continuous barrier wall

Highway 96 across the dam is planned to remain open, as well as Long Branch Campground downstream of the dam, throughout the two and one-half year contract. The Center Hill Dam has been identified by the Army Corps of Engineers as a high risk dam due to foundation seepage. A 2008-2010 grouting contract was an important first step to reduce the seepage and to prepare the foundation for construction of the barrier wall.

"We are currently studying the appropriate improvements for the saddle dam, a smaller earthen dam northeast of the main dam" Adcock said.

The saddle dam work will be the third large contract. A final small contract will be required for site restoration.

In December 2010, the first important phase of the rehabilitation, foundation grouting, was completed. IN this three-year construction contract, more than 50 miles of drilling of small holes was completed in order to pump over 1.5 million gallons of grout (which is a concrete mixture) into the rock foundation to make it stronger. Water moving through the foundation has been decreased and the dam is safer now than before the work was done.

The process of selecting a contractor is currently underway for the next contract to construct a concrete barrier wall from the top of the dam 300 feet down through the earthen embankment and into the rock foundation. This is highly specialized work to safely and effectively construct this barrier wall. We antici-pate awarding this construction contract in September 2011 and equipment to begin arriving near the end of the year. The contract will continue until mid 2014.

News

Center Hill Dam rehabilitation continues with barrier wall installation

LANCASTER, Tenn. (Feb. 14, 2014) - The U.S. Army Corps of Engineers Nashville District’s ongoing foundation rehabilitation project at Center Hill Dam is making progress as work crews continue to drill deep into the main dam earthen embankment to install a subsurface concrete wall. The current efforts are the second of three major contracts from 2008 to 2017 that comprise ongoing efforts to rehabilitate Center Hill Dam.

Corps environmental assessment underway at Center Hill Dam

LANCASTER, Tenn. (Oct. 9, 2012)  - The U.S. Army Corps of Engineers Nashville District’s ongoing major rehabilitation project at Center Hill Dam recently passed an important milestone with the completion of an environmental assessment public and agency review period for the project’s next phase located below the saddle dam.

Construction begins with ‘first bite’ on foundation barrier wall at Center Hill Dam

LANCASTER, Tenn. (July 11, 2012) – The “first bite” of a $106 million drilling project to stabilize the earthen portion of the Center Hill Dam with a barrier wall was taken today by the U.S. Army Corps of Engineers Nashville District and its contractor, Bauer Foundation Corporation, as the auger of a giant drill rig turned up the first dirt to the cheers of spectators.

Black visits Center Hill Dam Foundation Remediation Project

LANCASTER, Tenn.  (May 3, 2012) – U.S. Rep. Diane Black visited Center Hill Dam today to see firsthand the ongoing foundation remediation project and to receive updates from U.S. Army Corps of Engineers Nashville District personnel overseeing the work.

Exploratory drilling brings out benefits of partnership between districts

SILVER POINT, Tenn. (March 14, 2012) – A drill rig crew from the U.S. Army Corps of Engineers Baltimore District extracted core samples here today that are being closely examined by Nashville District geologists at Center Hill Lake near what is known as the Saddle Dam. However, the exploratory drilling is revealing more than just the condition of rock formations; it’s also bringing out the benefits of the two districts partnering together to explore the movement of water seepage through the karst geology in the area.