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Since March of 2005, we have attempted to keep fall, winter and early spring lake levels from extreme rises. The seepage problems are made worse during continual high lake levels, therefore, maintaining lower lake elevations is necessary until we get a permanent remedy in place. We have also attempted to operate the lake on the low end of our normal annual operating band. During construction, however, we plan to target Center Hill Lake levels between elevation 630 feet above mean sea level (msl) in the summer and no lower than elevation 618 msl during the late fall and early winter.

Center Hill Dam Safety Rehabilitation Project

Currently, four issues are relevant:

Center Hill Dam Aerial Photo1)     The main dam foundation remediation work, grouting and cutoff wall, is complete and significant project risk has been reduced.  Saddle dam work has begun.

2)     Center Hill Lake levels will remain lowered throughout 2017 as the Corps completes the foundation work for the saddle dam concrete berm.

3)     With major risk addressed, the Nashville District will begin a study to evaluate potential risk with main dam spillway gate operability issues, during extreme flood events, to determine if rehabilitation and/or replacement is needed.

4)     As conditions permit, the tentative plan is to raise the Center Hill Lake level an increment of 5 to 10 feet for the summer of 2018, dependent upon berm foundation completion, environmental commitments, and results of the gate study. 

Current status of the dam fix

Center Hill Dam Seepage Rehabilitation Project Work PlatformThe U.S. Army Corps of Engineers Nashville District is implementing a plan to address serious foundation seepage issues at Center Hill Dam.  The purpose of the ongoing construction is to ensure the long term reliability of the dam. The total project rehabilitation began in 2008 and is scheduled to be completed in 2019. Two of three large construction contracts comprising the foundation repair plan are completed and the third is underway.  The first two major contracts addressed the earthen embankment of the main dam and the left rim (to the southwest of the dam). Grout, a flowable concrete mix, was placed into the foundation rock beneath and beside the dam from 2008 to 2010 to fill solution features, to gather information about the rock, and to prepare the foundation for construction of a deep foundation barrier wall. The barrier wall was constructed 2012 to 2105.  An approximate 2.5-foot thick concrete wall was constructed into the earthen embankment up to 310 feet of depth from the top of the dam.  The wall is a permanent long term seepage barrier.  The third major construction contract was awarded in June 2016.  A concrete berm will be constructed to protect the earthen saddle dam.  The saddle dam fills a low area in the topography just east of the main dam to hold the lake.  The concrete reinforcing berm foundation work is underway.  The berm will be built downstream of the saddle dam through 2019.  Throughout construction we continue to closely monitor the dam.

Lake levels throughout construction

 

Maintaining lower lake elevations is necessary to keep high pressures off the dam embankments during construction and also to facilitate lowering the lake in the event of an emergency.  The project will be reassessed when enough of the construction is complete to lower risk, estimated late 2018.  At that time we will determine the appropriate lake levels for the future.  We anticipate lake levels will return to normal.   

During construction, the Corps has targeted Center Hill Lake levels between elevation 630 feet above mean sea level (msl) in the summer and no lower than elevation 618 msl during the late fall and early winter.  These elevations are approximately fifteen to twenty feet lower than preconstruction lake operating levels.  The chosen levels are the result of an Environmental Impact Statement (EIS) developed in 2007 and included consideration of safety concerns, potential impact to project purposes, and the views of the State of Tennessee, other federal agencies, affected stakeholders, and the public. The goal of the EIS was to identify an alternative that balanced the safety of the downstream human and natural environment against the reduction of project benefits from water supply, water quality, recreation, navigation, and hydropower.

Emergency action and information

Although not anticipated, there are events that could cause the Corps to lower the lake as an emergency action. Also, your County Emergency Managers have maps of areas which could flood if Center Hill Dam were to fail. The Corps has an aggressive Dam Safety program to constantly monitor all of our dams in the Cumberland River system and Center Hill is being monitored constantly. The Corps will use news articles, websites, and public meetings to keep the public informed of the dam’s condition and of progress of the foundation remedy throughout construction.

Accurate and timely information is critical to the effective resolution of many issues associated with Corps of Engineers projects. This web site has been established to provide information you need to stay informed. The site will be updated, based on the needs of our site visitors. Please let us know what you need. Please share this site with others interested in this project.