2010 Metro Mitigation Plan

Through the Corps of Engineers dam safety inspection program, seepage concerns associated
with a karst foundation were identified at the project. In 2005, a Major Rehabilitation Report
was completed and approved at US Army Corps of Engineers headquarters which called for a
long term rehabilitation of the project to include a grout curtain and concrete diaphragm wall
to run the entire length of the earthen embankment and upstream of the right most concrete
monoliths. The first phase of the construction project began in March 2006 and is estimated
to be completed in October 2012 at an estimate cost of $584 million dollars. To insure the
safety of the dam of those living in the downstream communities an interim pool restriction at
the project was put into place in January 2007 that targets a pool elevation of 680 ft for
operation of the reservoir.
Center Hill Dam
Center Hill Dam is located at river mile 26.6 of the
Caney Fork River above its confluence with the
Cumberland River at river mile 309.2. The reservoir
is located in Dekalb, Putnam, and White Counties in
Tennessee. The dam impounds a reservoir that is 64
miles long and has 415 miles of shoreline. During
flood conditions Center Hill Dam has the capability
of storing , 2,092,000 acre-ft of water. The reservoir
contains 18,220 acres of surface area at a normal
summer pool elevation of 648 ft., and 23,060 acres
of surface area at a flood control storage elevation of
760 ft.
Figure 4-4c. Center Hill Dam
Dam
Through the Corps of Engineers dam safety inspection program, concerns associated with a
karst limestone foundation were identified at the dam. In 2006, a Major Rehabilitation Report
was completed and approved at US Army Corps of Engineers headquarters which called for a
long term rehabilitation of the project to include modern concrete cutoff walls through the
embankment and into the foundations and grouting beneath the entire dam and along both
sides of the dam. The construction project, began in 2008, and is expected to be completed in
2014 at a cost of $249 million.
Dam Failure Flooding
Dam failure flooding can occur as the result of partial or complete collapse of an
impoundment. Dam failures are often the result of prolonged rainfall and flooding or, during
very dry conditions, erosion. The primary danger associated with a dam failure is the swift
flooding of those properties immediately downstream of the dam.
In Tennessee, there are more than 1,200 dams and, fortunately, significant dam failures occur
on an average of less than once every 40 years. There are large dams within the state,
including those operated by the Tennessee Valley Authority and the U. S. Army Corps of
Engineers. These dams serve to produce electrical power for the state, control flooding, and
to provide recreational opportunities to the state's citizens and its visitors. Dam failures are an
Metropolitan Nashville - Davidson County
Hazard Identification
Multi-Hazard Mitigation Plan Page 4-11
April 2010