[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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