[Federal Register Volume 72, Number 37 (Monday, February 26, 2007)]
[Notices]
[Pages 8358-8359]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 07-853]


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DEPARTMENT OF DEFENSE

Department of the Army; Corps of Engineers


Intent To Prepare a Draft Environmental Impact Statement To 
Address Operational Changes at Center Hill Dam, Center Hill Lake, 
DeKalb County, TN, That Could Affect Pool Elevations

AGENCY: Department of the Army, U.S. Army Corps of Engineers, DoD.

ACTION: Notice.

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SUMMARY: The Corps of Engineers (Corps) is preparing a Draft 
Environmental Impact Statement (DEIS) to address operational changes at 
Center Hill Dam that could affect pool elevations. Center Hill Dam 
impounds Center Hill Lake in central Tennessee. The DEIS is necessary 
to provide National Environmental Policy Act (NEPA) compliance to 
address changes that could include, but are not limited to water 
quality, aquatic, riparian, and terrestrial habitat, recreation, water 
supply, flood storage, economics, hydropower production, and safety as 
a result of operating Center Hill Lake below normal pool elevations for 
extended periods of time. Several engineering studies have identified a 
heightened level of risk at Center Hill Dam due to increasing seepage 
problems under and around the dam. Since March 2005, the Corps has 
attempted to keep fall, winter and early spring lake levels from 
extreme rises due to high inflow. Seepage problems are made worse 
during continual high lake levels. As a result, the Corps plans to 
maintain lower lake levels, but still within the operations curve, to 
reduce pressure on the dam foundation, abutments, and rim walls until a 
permanent remedy is in place. A major grouting project to address the 
dam seepage is scheduled for the fall of 2007, followed by installation 
of a cutoff wall through the earthen portions of the dam and adjoining 
rim walls. Although not anticipated, the Corps may have to lower the 
lake pool significantly below the operating pool should seepage 
conditions worsen, or new information determine this action is 
necessary to reduce risk. This notice serves to initiate the NEPA 
process. The Corps plans to prepare and circulate a DEIS which serves 
to cover possible impacts due to extreme changes in lake levels that 
could occur during the repair of the dam's foundation and abutments.

DATES: Written comments concerning issues to be considered in preparing 
the DEIS, must be received by the Corps of Engineers on or before March 
28, 2007.

ADDRESSES: Written comments on issues to be considered in the DEIS 
shall be mailed to: Joy Broach, Project Planning Branch, Nashville 
District Corps of Engineers, P.O. Box 1070 (PM-P), Nashville, TN 37202-
1070. Comments may also be e-mailed to: 
[email protected].

FOR FURTHER INFORMATION CONTACT: For additional information concerning 
the notice, please contact Joy Broach, Environmental Team, (615) 736-
7956, Linda Adcock, Center Hill Dam Seepage Major Rehabilitation 
Project Manager, (615) 736-5940, or Public Affairs Office, (615) 736-
7161.

SUPPLEMENTARY INFORMATION:
    1. Center Hill Dam was designed in the 1930s, constructed in the 
1940s, and impounded in the early 1950s. The dam was built on karst 
geology using accepted engineering practices of the day. Since the 
1960s, seepage flows through the dam's right abutment and left rim wall 
have been monitored, and recently became a concern with increased 
seepage and development of turbid flows through springs below the left 
rim wall. Signs of seepage increase through the main dam and saddle dam 
foundations have also been noted. A formal risk assessment is currently 
being conducted to determine if a need exists to significantly alter 
lake levels outside the normal operations curve to reduce risk to 
people and property.
    2. A comprehensive plan for repairs has been approved; however, 
these repairs will take a number of years to implement. Until the 
repairs are sufficiently complete, the Corps has determined that it is 
in the public's interest to operate Center Hill Lake at the lower range 
of the operations curve. Many rehabilitation alternatives were 
considered and potential impacts analyzed and are discussed in the 
following NEPA documents: Proposed Center Hill Dam Seepage 
Rehabilitation, Environmental Assessment, July 2005; and Proposed 
Center Hill Dam Seepage Rehabilitation, Environmental Assessment 
Supplement 1, March 2006. These documents have been included by 
reference. No significant environmental and economic consequences are 
anticipated under current dam repair plans; however,

[[Page 8359]]

some water intakes and boat ramps may need to be extended for safe 
operation.
    3. Though not expected, the Corps recognizes that if seepage 
conditions worsen, or new information determines that the lake 
elevations should be significantly changed to ensure the public's 
health, safety, and welfare; then the following resources could be 
significantly impacted:
    (1) The cold-water fisheries both in the lake and tailwater;
    (2) Water quality throughout the Caney Fork River and downstream in 
the Cumberland River;
    (3) Federally listed threatened and endangered species;
    (4) Designated uses of the waterway including fish and aquatic 
life, livestock watering and wildlife, irrigation;
    (5) And economics including electric power production, municipal 
and industrial water supply, recreation, navigation, flood damage 
reduction, and disruption to communities, jobs, and other related 
factors.
    4. Current Actions to Reduce Risk. Several actions have already 
been taken to reduce the risk. Prior to 2005, spring rains were 
captured in the reservoir to maximize downstream flood protection and 
hydropower generation. Beginning in March 2005, the pool was managed 
more aggressively to reduce inflow peaks and adhere more closely to the 
prescribed guide curves. In 2006, continuous surveillance was initiated 
at the dam. This involves providing patrols to monitor the dam, known 
seepage and trouble spots, and downstream areas. Currently, the Corps 
is conducting exploratory drilling to assess the limestone rock 
condition and key access points for future grouting activities. 
Additional coordination and exercises have been held with state and 
local emergency management agencies. These agencies will be provided 
flood inundation maps to help coordinate emergency evacuation planning. 
The Corps has improved its emergency notification procedures, increased 
instrumentation in, on, and around the dam, and conducted numerous 
public meetings to advise the public of problems with the dam.
    5. A DEIS will be undertaken to review current actions taken and to 
consider other possible alternatives to reduce stress on the dam.
    6. This notice serves to solicit comments from the public; Federal, 
State and local agencies and officials; Indian Tribes; and other 
interested parties in order to consider and evaluate impacts of these 
proposed activities. Any comments received by the agency will be 
considered in determining future operations. In the decision-making 
process, comments are used to assess impacts on public health and 
safety, endangered species, historic properties, water quality, water 
supply and conservation, economics, aesthetics, wetlands, flood 
hazards, floodplain values, land use, navigation, shore erosion and 
accretion, recreation, energy needs, food and fiber production, mineral 
needs, considerations of property ownership, general environmental 
effects, and in general, the needs and welfare of the people.
    7. Activities proposed that may require a review under the 
guidelines promulgated by the Administrator, Environmental Protection 
Agency (EPA), under authority of Section 404(b)(1) of the Clean Water 
Act (40 CFR part 230) include fill placement for water intake 
extensions, boat ramp extensions, and other mitigation actions.
    8. Other Federal, State, and local approvals that may be required 
for proposed work are as follows:
    a. Section 401 water quality certification from the Tennessee 
Department of Environment and Conservation.
    b. Coordination with the U.S. Fish and Wildlife Service for the 
Endangered Species Act and Fish and Wildlife Coordination Act.
    c. Coordination with the Tennessee Wildlife Resources Agency.
    d. Coordination with the State Historic Preservation Officer and 
President's Advisory Council on Historic Preservation.
    9. Significant issues to be analyzed in the DEIS include impacts to 
fisheries, tailwater mussel resources, water quality, flood control, 
recreation, navigation, water supply, electric power production, 
economics, and community development. The U.S. Fish and Wildlife 
Service has agreed to be a Cooperating Agency on the DEIS. A DEIS 
should be available in June 2007.
    10. Public Meetings: At present, no public meetings have been 
scheduled to scope for potential issues to be evaluated in the DEIS. 
Requests for public meetings should be directed to Mr. William Peoples, 
Chief, Public Affairs Office, U.S. Army Corps of Engineers, Nashville 
District, Nashville, TN, 37202-1070. Mr. Peoples may be reached by 
telephone at (615) 736-7834.

Brenda S. Bowen,
Army Federal Register Liaison Officer.
[FR Doc. 07-853 Filed 2-23-07; 8:45 am]
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