Environmental statements; availability, etc.: Columbia Dam and Reservoir Project, TN; unfinished dam structure stabilization,

[Federal Register: May 27, 1999 (Volume 64, Number 102)]

[Notices]

[Page 28856-28857]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr27my99-115]

TENNESSEE VALLEY AUTHORITY

Stabilization of Unfinished Dam Structure of The Columbia Dam and Reservoir Project

AGENCY: Tennessee Valley Authority (TVA).

ACTION: Issuance of record of decision.

SUMMARY: This notice is provided in accordance with the Council on Environmental Quality's regulations (40 CFR 1500 to 1508) and TVA's implementing procedures. TVA has decided to implement the dam site stabilization Option 2 identified in its Final Environmental Impact Statement (EIS), Use Of Lands Acquired For The Columbia Dam Component Of The Duck River Project. The Final EIS was made available to the public in April 1999. A Notice of Availability of the Final EIS was published in the Federal Register on April 16, 1999.

The Final EIS also analyzed various uses of the property acquired for the Columbia Project. TVA has not yet made a final decision on the use of these properties, but expects to decide this soon. When the land use decision is made, another Record of Decision will be issued. Although the dam structure is located on project property, stabilizing the existing dam structure will have no effect on the land use decision. TVA has determined that the two actions are independent of each other.

FOR FURTHER INFORMATION CONTACT: Linda B. Oxendine, Senior NEPA Specialist, Environmental Management, Tennessee Valley Authority, 400 West Summit Hill Drive, WT 8C, Knoxville, Tennessee 37902-1499; telephone (423) 632-3440 or e-mail lboxendine@tva.gov.

SUPPLEMENTARY INFORMATION: In 1968, TVA proposed the Duck River Project that involved the construction of two dams and reservoirs on the Duck River in middle Tennessee, south of Nashville. As proposed, one dam was to be built at River Mile 248 near Normandy and the other at River Mile 136 near Columbia. Congress began appropriating money for the Duck River Project in December 1969. Construction of Normandy Dam and Reservoir began in June 1972 and was completed in 1976. Construction of the Columbia Dam and Reservoir was begun in August 1973 but was halted in 1983 because of the potential to jeopardize the continued existence of several endangered mussel species within the Duck River.

In 1995, after efforts to transplant endangered mussels to other stream reaches failed, TVA decided the Columbia Dam Project could not be completed. Accordingly, TVA proposed to address future use of the lands acquired for the project and what should be done about the unfinished dam structure.

The Columbia Project lands are located in the Duck River watershed between the city of Columbia (on the west) and U.S. Route 431, Lewisburg-Franklin Pike (on the east), in Maury County, Tennessee. The reach of the Duck River included in this study extends from approximately River Mile 130, in Columbia, upstream to River Mile 165, at Carpenters Bridge, 3 kilometers (2 air miles) west of U.S. Route 431.

When construction of Columbia Dam was halted in 1983, the Columbia Project was about 45 percent complete. The concrete portion of the dam was about 90 percent complete and the earth-filled section was about 60 percent complete. The river had been diverted through a 600-meter (2000-foot) long constructed channel located along the east side of the work site (the diversion channel) and a dike had been built to keep normal stream flow out of the construction site. Approximately 46 percent of the land required for the reservoir (5200 of 11,140 hectares

[12,800 of 27,500 acres] ) had been acquired, and approximately half of the 72 kilometers (45 miles) of roads affected by the reservoir had been relocated.

On February 25, 1995, TVA issued a Notice of Intent to prepare an EIS on alternatives for use of lands acquired for the Columbia Project. The Tennessee Duck River Development Agency, the U.S. Army Corps of Engineers, and the U.S. Fish and Wildlife Service decided to cooperate in the preparation of this EIS. A public scoping meeting was held at Culleoka School near the Project site on April 18, 1995. The Notice of Availability of the Draft EIS was published on January 6, 1997. The public and interested agencies were invited to submit written comments on the draft or to attend a public meeting on January 27, 1997 at Columbia Senior High School.

TVA received a total of 2,890 separate sets of comments which included input from over 4,600 individuals, three federal agencies, four state agencies, six identified county and local governmental agencies, and over 20 other organizations. The comments indicated that most people and agencies want the Columbia Project lands to be available for a variety of public uses and little or none of this land used for industrial, commercial, or residential development. Only 43 comments were received about the existing dam structure and what should be done about it. Comments were mixed, but most supported implementation of Option 2, stabilization of the dam with a lower profile. The Notice of Availability of the Final EIS was published on April 16, 1999.

[[Page 28857]]

Alternatives Considered

To address the effects of the existing dam structure, construction dike, and diversion channel on the river and its flow, three dam site stabilization options were evaluated. Under Option 1--Maintain Current Status of the Dam Structures, TVA would remove or minimize possible safety and environmental hazards on and around the dam and diversion channel site. Under Option 2--Stabilize Existing Flood Profile, TVA would modify the existing concrete and earthen components of the dam to stabilize the present control on flood flows. The concrete and earthen portions of the dam would be demolished and reshaped at a lower elevation to maintain existing upstream flood elevations and preserve downstream flood benefits. Under Option 3--Restore Original Hydraulic Conditions, TVA would remove enough of the concrete and earthen structures at the dam site to reestablish pre-construction hydraulic conditions along this part of the river. Option 2 was identified as TVA's preferred alternative.

Decision

TVA has decided to implement Option 2 because this would stabilize flood elevations at their current levels, address public safety concerns, and avoid substantial additional construction in the river. Option 1 would not address public safety concerns as effectively as Option 2. Under Option 1, the existing dam structure would be left largely intact and in place and have a continuing effect on the visual setting of the area. Option 3 would fully address public safety concerns and return the river to its pre-construction hydraulic level, but completely removing the dam structure would increase downstream flood elevations and have required considerable more work in the river with associated environmental impacts.

Environmentally Preferable Alternative

Except for aesthetic impacts, TVA has concluded that Option 1 is the environmentally preferred alternative because it would minimize potential adverse impacts to the pond and fringe wetlands which exist adjacent to the concrete part of the dam. However, Option 2 would more effectively address public safety concerns at the dam site. Under Option 2, the shape and height of the modified dam would also have less of a visual impact on the landscape. Although Option 2 could involve some work in the river, TVA has determined that the potential environmental impacts of Option 2 will be insignificant.

Environmental Mitigation

Standard construction, demolition, and best management practices would be followed in all aspects of the dam stabilization project to minimize noise, erosion, dust, and other potential impacts. Disturbed areas will be seeded and planted with native vegetation to help stabilize the site and to promote the re-establishment of the natural ecosystem.

Dated: May 17, 1999. Ruben O. Hernandez, Acting Executive Vice President, River System Operations and Environment.

[FR Doc. 99-13534Filed5-26-99; 8:45 am]

BILLING CODE 8120-08-U