Bear Creek Dam Leakage Resolution Project, Franklin County, AL, 52596-52598 [E7-18146]

Agencies

• Tennessee Valley Authority

[Federal Register Volume 72, Number 178 (Friday, September 14, 2007)]
[Notices]
[Pages 52596-52598]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-18146]


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TENNESSEE VALLEY AUTHORITY


Bear Creek Dam Leakage Resolution Project, Franklin County, AL

AGENCY: Tennessee Valley Authority (TVA).

ACTION: Issuance of Record of Decision.

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SUMMARY: This notice is provided in accordance with the Council on 
Environmental Quality's regulations (40 CFR parts 1500 to 1508) and 
TVA's procedures implementing the National

[[Page 52597]]

Environmental Policy Act. TVA has decided to implement Alternative 2--
Modify Dam and Maintain Summer Pool Level of 576 Feet, the preferred 
alternative identified in its Final Environmental Impact Statement 
(EIS), Bear Creek Dam Leakage Resolution Project.

FOR FURTHER INFORMATION CONTACT: Charles P. Nicholson, NEPA Policy 
Program Manager, Environmental Stewardship and Policy, Tennessee Valley 
Authority, 400 West Summit Hill Drive, WT 11B, Knoxville, Tennessee 
37902-1401; telephone (865) 632-3582 or e-mail cpnicholson@tva.gov.

SUPPLEMENTARY INFORMATION: TVA completed Bear Creek Dam in 1969 at mile 
74.6 on Bear Creek in Franklin County, Alabama. The dam and associated 
reservoir are part of the Bear Creek Project authorized for the 
purposes of flood control, recreation, and economic development, 
including water supply. Excessive leakage of water has occurred through 
the foundation of Bear Creek Dam since its completion and this 
increases the risk of dam failure. TVA has unsuccessfully attempted 
repairs on several occasions. The most recent of these repair efforts 
was in 2004-2005; after TVA refilled the reservoir to its normal summer 
pool level of 576 feet above sea level, excessive leakage continued. 
Since then, TVA has operated the reservoir at a reduced summer pool 
level of 568 feet as a precautionary measure to reduce the leakage and 
provide a greater margin for flood management. However, following 
periods of heavy rainfall, the reservoir level can rise, and the risk 
of dam failure increases. TVA prepared this EIS to evaluate 
alternatives for a long-term solution to the problem of excessive 
leakage through Bear Creek Dam.
    TVA published a Notice of Intent to prepare this EIS in the Federal 
Register on June 2, 2006. A public scoping meeting was held on June 20, 
2006 and attended by about 150 people. Scoping comments were received 
from two federal agencies, four state agencies, and several 
individuals. The Notice of Availability of the Draft EIS was published 
in the Federal Register on June 1, 2007. TVA held a public meeting on 
the Draft EIS on June 26, 2007 and accepted comments through July 16, 
2007. Comments on the Draft EIS were received from three federal 
agencies, one state agency, three local public water suppliers, and 
three individuals. The Notice of Availability of the Final EIS was 
published in the Federal Register on August 10, 2007.

Alternatives Considered

TVA identified four alternatives in the EIS

    Under Alternative 1, the No Action Alternative, TVA would not 
implement a long-term solution to the leakage problem and would attempt 
to operate the dam at the originally-intended summer pool level of 576 
feet. Normal winter pool would remain at 565 feet. Under this 
alternative, TVA would implement new seasonal minimum flows from the 
dam as recommended by the U.S. Fish and Wildlife Service to improve 
habitat conditions for endangered species in Bear Creek downstream of 
the dam. Adoption of Alternative 1 would not remedy the leakage 
problem, and the dam would be at risk of failure, which would cause 
downstream flood damage. Although this alternative differs from the 
current interim operating regime, it better represents the historic 
baseline conditions.
    Under Alternative 2, Modify Dam and Maintain Summer Pool Level of 
576 Feet, TVA would repair or rebuild the dam in place or immediately 
downstream and restore the normal summer pool to 576 feet. TVA would 
also implement the new seasonal minimum flows described above for 
Alternative 1 and raise the normal winter pool by one foot to 566 feet. 
The existing roadway across the dam would be returned to service 
following dam repairs. Three sub-alternatives are considered under this 
alternative. Alternative 2a is the construction of a roller-compacted 
concrete structure at the downstream edge of the existing dam. This 
structure would be keyed into the bedrock, and a cutoff wall would be 
installed beneath the structure to prevent seepage. Alternative 2b is 
the placement of additional earth fill on the downstream dam face and 
the installation of a cutoff wall into bedrock on the downstream side 
of the dam. Alternative 2c is the installation of a cutoff wall into 
bedrock on the upstream dam face.
    Under Alternative 3, Lower Dam and Maintain Summer Pool Level of 
565 Feet, the existing dam would be partially removed and stabilized. A 
grout curtain or cutoff wall would be installed within the dam and into 
the underlying bedrock to prevent seepage under the dam. The existing 
roadway across the dam would be rebuilt. The reservoir pool level would 
be maintained at approximately 565 feet throughout the year.
    Under Alternative 4, Remove Dam and Restore Former Creek Channel, 
TVA would remove Bear Creek Dam and the reservoir would be eliminated. 
The former creek channel would be dredged of excess sediment to 
facilitate water flow. A bridge would be built to replace the existing 
roadway over the dam.

Comments on the Final EIS

    The U.S. Environmental Protection Agency (EPA) commented on the 
final EIS. Their comments focused on potential effects to wetlands and 
sought clarification of responses to previous EPA comments on the draft 
EIS. Due to favorable hydrologic conditions, approximately 77 acres of 
scrub-shrub, emergent, and aquatic bed wetlands have developed at 
various locations around the reservoir fringe at the interim summer 
pool elevation of 568 feet. None of these wetlands is forested. The 
forested wetlands on Bear Creek Reservoir are confined to the heads of 
coves where tributary streams enter the reservoir. The hydrology of 
these areas depends on the tributary streams, and the forested wetlands 
are generally unaffected by fluctuation in the reservoir level. 
Forested/scrub-shrub wetlands also occur on flats associated with 
Island Branch and further upstream. Based on the size of trees present, 
these wetlands have persisted in this location for over 20 years and 
would not be inundated when the reservoir is refilled. No forested 
wetlands would be affected adversely under Alternatives 1 and 2. 
Forested wetlands have not developed in the drawdown zone between 
elevation 576 feet (normal summer pool) and 565 (normal winter pool) 
because tree growth is inhibited by extended inundation during the 
growing season.
    Because they perform only minor wetland functions due to their 
fringe nature and because traditionally accepted hydric soil 
characteristics are not present, TVA does not consider these wetlands 
to be jurisdictional wetlands in accordance with the Clean Water Act. 
Accordingly, no compensatory mitigation is required to offset their 
loss.
    Bear Creek Reservoir is narrow with fairly steep, rocky banks and 
few areas of overbank. Fringe wetlands are likely to become 
reestablished along parts of the normal (576 foot) summer shoreline, 
particularly in bottomland areas associated with tributaries, if the 
reservoir were refilled under Alternative 1 or 2. Shoreline steepness 
and the presence of adequate soil substrate are the primary factors 
affecting wetland development at the current 568-foot summer pool level 
and at the 576-foot normal summer pool elevation under Alternatives 1 
and 2. Competition from exotic plants or animal life does not

[[Page 52598]]

appear to present any barrier to wetland establishment.
    Much of the Bear Creek Reservoir shoreline has eroded since the 
reservoir was filled in 1969, and rock outcrops and bluffs are common 
along the shoreline. No critically eroding shoreline has been 
identified. At the 576-foot elevation, shoreline vegetation present 
prior to the 2005 emergency drawdown has not decreased. Refilling the 
reservoir under Alternatives 1 and 2 is not expected to cause 
additional erosion. Thus, establishment of shoreline buffers to prevent 
erosion is neither feasible nor necessary.
    Returning the reservoir to its original full summer pool is 
expected to result in water quality conditions virtually identical to 
the pre-2005 conditions. Most of the shoreline surrounding Bear Creek 
Reservoir is undeveloped and forested. Runoff from upland areas enters 
the reservoir primarily via tributary streams. The degree of upland 
runoff filtered by wetlands is dependent on those wetlands present in 
coves and associated with streams. These areas have not been affected 
dramatically by changes in reservoir levels. Historically, low levels 
of dissolved oxygen have occurred in the deeper portions of the 
reservoir. Currently there are no plans to improve dissolved oxygen. 
However, TVA will continue to monitor water quality on Bear Creek 
Reservoir and would take remedial measures as necessary.

Decision

    TVA has decided to implement Alternative 2, Modify Dam and Maintain 
Summer Pool Level of 576 Feet. Under this alternative, the original 
project objectives of flood control, recreation, economic development, 
and water supply would be met. The new seasonal minimum flows would 
improve conditions for endangered species downstream of the dam, and 
the one-foot increase in the winter pool level would improve operating 
conditions for the public water supply intake and treatment plant on 
the reservoir.
    Three alternative methods of repairing the dam are identified in 
the EIS. TVA has selected Alternative 2a, the construction of a roller-
compacted concrete structure at the downstream edge of the existing 
dam.

Environmentally Preferred Alternative

    Alternative 2--Modify Dam and Maintain Summer Pool Level of 576 
Feet is the environmentally preferred alternative. Implementation of 
this alternative would afford a stable water supply source for the 
Franklin County Water Service Authority and would restore water-based 
recreational opportunities on Bear Creek Reservoir. Repair of the dam 
under this alternative would provide increased flood protection to 
downstream areas compared to the other alternatives. Operation of the 
dam under Alternative 2 to provide target minimum flows would provide 
improved water quality for three federally listed mussel species known 
to occur downstream of Bear Creek Dam.
    The potential environmental consequences of implementing any of the 
three Alternative 2 repair methods are similar. However, Alternative 
2a--Roller-Compacted Concrete Structure is preferable to the other two 
methods in that it would most likely provide the best long-term 
solution to the leakage problems. It would provide protection against 
the probable maximum flood. The need for future construction 
disturbance would be reduced under Alternative 2a.

Mitigation

    Standard construction best management practices would be followed 
in all aspects of the proposed repairs and construction to avoid or 
minimize adverse environmental impacts. TVA would ensure that all 
necessary permits are obtained from the appropriate regulatory agencies 
and that permit requirements are met. TVA would ensure that all site 
operations adhere to the requirements in each permit and would employ 
all necessary actions to minimize environmental impacts. The following 
non-routine measures would be implemented to reduce the potential for 
adverse environmental effects:
     Construction buffers would be delineated around any caves 
within one-fourth mile of a construction area. The buffer for caves 
would be 200 feet. Within this buffer, vegetation would not be cleared, 
and vehicles or equipment would be restricted to existing roads.
     TVA would increase patrols and monitoring of cultural 
resources within the reservoir drawdown area until conditions are 
stabilized or protected.
     Archaeological surveys as required by the Memorandum of 
Agreement between TVA and the Alabama State Historic Preservation 
Officer will be conducted, and mitigation will be performed on any 
sites or resources determined to be eligible for inclusion on the 
National Register of Historic Places in accordance with the terms of 
the Memorandum of Agreement.

    Dated: September 10, 2007.
Janet C. Herrin,
Senior Vice President, River Operations.
 [FR Doc. E7-18146 Filed 9-13-07; 8:45 am]
BILLING CODE 8120-08-P