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Finding of No Significant Impact

Adoption of Environmental Assessment prepared by the U.S. Army Corps of Engineers

Section 26a approvals for Tennessee State Route 13 proposed wetland impacts, channel relocation, culvert extension, and bridge construction at Duck River mile 24.6, Humphreys County, Tennessee

Proposed Action and Need
Alternatives
Public and Intergovernmental Review
Impacts Assessment
TVA Review
Mitigation
Conclusion and Findings

Proposed action and need

On September 7, 2001, the Tennessee Department of Transportation (TDOT) submitted to the Tennessee Valley Authority (TVA) and the United States Army Corps of Engineers (USACE) a joint application for channel relocation, culvert extension, and bridge construction across the Duck River at River Mile 24.6. These proposed activities are associated with the construction improvements for Tennessee State Route (SR) 13 in Humphreys County, Tennessee. The purpose of the proposed action would be to replace an old, deteriorating bridge and its approaches with a new structure for public safety. A Section 26a approval would be needed for the following actions:

  • Bridge construction at Duck River Mile 24.6. The proposed work at this site would involve the discharge of dredged or fill material associated with constructing a new bridge adjacent to the existing bridge on the west side. Two piers would be constructed below the ordinary high-water mark. The existing bridge would be completely removed after construction of the new bridge.
  • Box culvert extension on an unnamed tributary (Mile 0.3), to the Duck River at Mile 24.4L. The proposed work would involve extending an existing 77-foot box culvert by an additional 75 feet.

Under the terms of a Memorandum of Understanding between TVA and the Department of the Army, dated August 12, 1985, TVA served as a cooperating agency in the preparation of the USACE Environmental Assessment. TVA commented on a draft of the USACE EA. The proposed bridge replacement and box culvert extension require approval under Section 26a of the TVA Act. Because of the presence of wetlands and National Register of Historic Places (NRHP) cultural resources, the agencies decided that an EA would allow a better understanding of the impacts of this proposal. TVA has determined that the impacts of its Section 26a approvals for the improvements on SR 13 over the Duck River in Humphreys County are adequately assessed in the USACE EA and FONSI of October 2, 2002. TVA adopts this EA as its own based upon independent review of the project.

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Alternatives

The USACE EA evaluates the environmental consequences of three alternatives, No Action, the Applicant’s Proposed Action, and the Applicant’s Proposed Action with Additional Modifications and/or Special Conditions. Under No Action, the new bridge would not likely be constructed. Under the Applicant’s Proposed Action, the highway would be constructed. Under the Applicant’s Proposed Action with Additional Modifications and/or Special Conditions, measures to mitigate impacts to wetlands and the aquatic environment would be added to the DA and TVA permit. These measures primarily include:

  • Performing construction activities in wetlands and unnamed tributaries in the dry or low flow conditions.
  • Properly stabilizing the new channel prior to flow diversion.
  • Purchasing wetland credits at the Coffee County Wetland Bank.
  • Revegetating temporary wetland impacts.
  • Constructing instream piers in the dry within cofferdams.
  • Assuring that instream construction activities including construction of cofferdams and construction pad will not occur during the pygmy madtom (Noturus stanauli) spawning season.
  • Removing the old bridge in such a way as to not allow large pieces to fall into the river.
  • Complying with all the mitigation measures in the Memorandum of Agreement (MOA) between the Federal Highway Administration (FHWA) and the Tennessee State Historic Preservation Officer (SHPO). TDOT, TDEC, Chickasaw Nation, and Muskogee (Creek) Nations are concurring parties on this MOA.
  • Implementing erosion and sedimentation control measures.

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Public and Intergovernmental Review

USACE, TVA, and the state of Tennessee issued Joint Public Notice 01-91 announcing the project on December 3, 2001. Comments were received in response to the notice by state and federal agencies. These included comments from the United States Fish and Wildlife Service (USFWS) and the THC.

The USFWS expressed concerns regarding potential impacts to the pygmy madtom. In order to minimize the potential impacts, the USFWS recommended special conditions for the DA/TVA permit. The USACE included these as special conditions in their permit, and these are also listed in the mitigation section of this FONSI.

THC stated that the project as proposed in the public notice may adversely affect properties that are eligible for listing in the NRHP. An MOA was prepared to stipulate mitigation measures needed for two prehistoric archaeological sites eligible for the NRHP which cannot be avoided.

The Tennessee Department of Environment and Conservation issued the certification required under Section 401 of the Clean Water Act on July 16, 2002. USACE issued a DA permit pursuant to Section 404 of the Clean Water Act on October 22, 2002.

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Impacts Assessment

There would be temporary impacts on water quality and air quality from construction activities. Impacts to recreation, aesthetics, and from project noise would be minimal. Less than 1 acre (0.25 acre) of wetlands would be permanently filled, with mitigation occurring through purchases from the Coffee County Wetland Mitigation Bank. An additional 0.24 acre of wetlands would be temporarily impacted. As mitigation for these temporary impacts, TDOT would seed the area and return it to the original elevations. Native wetland tree species would be planted in order to return it to a forested wetland.

The USFWS concurred with a not likely to adversely affect finding for the bald eagle (Haliaeetus leucocephalus), pink mucket (Lampsilis abrupta), orange-footed pearlymussel (Plethobasus cooperianus), and rough pigtoe (Pleurobema plenum). They also concurred with a “not likely to adversely affect” determination for the pygmy madtom provided specific measures were incorporated into the project plan. These are listed in the mitigation section of this FONSI and in the USACE EA and permit.

The existing bridge was determined not to be eligible and two archaeological sites in the footprint of the new bridge were determined to be eligible for the NRHP, but an MOA between the FHWA and the Tennessee State Historic Preservation Officer regarding Mitigation of Adverse Effects for the State Route 13 Bridge Replacement Project was executed on August 12, 2002, pursuant to Section 106 of the National Historic Preservation Act. The MOA describes measures that will ensure that the impacts on historic properties will be taken into account during archeological excavation and recovery.

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TVA Review

TVA independently reviewed the impacts assessed in the USACE EA and confirmed its findings. TVA concurs with the USACE’s finding that there is no practicable alternative to routing the highway across the floodplain of the Duck River because the bridge replacement could not be constructed without crossing the floodplain, and it would be costly to move the highway to another location. TVA concurred that impacts to aquatic resources would be minimized through the use of standard Best Management Practices, and the USFWS recommended special conditions for water quality protection. Although the TVA Regional Natural Heritage Project database records for Humphreys County indicated that several state-listed threatened and endangered plant species are known from the county, no recorded state-listed threatened or endangered plants were noted within a mile of the project. The potential of this project to impact these species adversely is low.

TVA has determined that the proposed mitigation in the Coffee County Wetland Mitigation Bank is appropriate because there are no suitable on-site mitigation areas. On-site mitigation for the loss of 0.24 acre of palustrine-forested wetlands was considered by USACE. USACE determined that the Wetland Mitigation Bank was the best option for in-kind mitigation, with the Coffee County Bank being the closet bank to the site. The filling in Wetland “A” would not affect the springhead, which is the hydrologic input for Wetland “C,” because the highway separates the two wetlands. Wetland soils in the temporarily impacted wetland area would be preserved and replanted with trees. For seeding of wetland areas, native species have been specified. TVA is not aware of other nearby projects with the potential to cumulatively affect wetlands and the Duck River. The SR 13 bridge project is the only highway construction project in the area listed in the State Transportation Improvement Program. Because of the policy requirement that there be no net loss of wetland and stream functions and values, the incremental impact of this project when combined with other actions would not be significant. All future actions would continue to be subject to the “no net loss” requirement.

In order to fulfill Section 106 compliance obligations of the National Historic Preservation Act, TVA requested to be included as a concurring party on the MOA. TVA signed as a concurring party on January 9, 2003.

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Mitigation

This FONSI is contingent upon successful implementation of Best Management Practices for erosion and sediment control, the debiting of 1.0 acre of credit from the Coffee County Wetland Mitigation Bank to offset permanent wetland impacts at a 4:1 ratio, and on-site mitigation for temporary impacts to 0.24 acre. The applicant will replant the temporarily impacted area with native wetland tree species in order to offset the impacts adequately. Also, as recommended by the USFWS to reduce the effects to the pygmy madtom, the following special conditions will be added to the TVA permit:

  • No in-stream work will occur from April 15 to July 15, which is the spawning period of the pygmy madtom.
  • In-stream piers will be constructed in the dry within cofferdams. Construction of the cofferdams will not occur from April 15 to July 15 (the pygmy madtom spawning season). Once the cofferdams are in place, construction of the piers may proceed.
  • If suspended sediment is visible in the water inside the cofferdams, it will not be pumped out immediately. Sediment will be allowed to settle, and the water will be pumped out slowly so as not to resuspend the sediment.
  • If an in-stream construction pad is needed, it will not be constructed from April 15 to July 15 (the pygmy madtom spawning season). The pad will be constructed of large, clean rock, and it will not be constructed more than one-third of the way across the river channel. Upon completion of bridge construction, the construction pad will be removed. Rock will be removed to no more than 1 foot from the river bottom.
  • The existing bridge will be removed in such a way as to not allow large pieces to fall into the river. Beams, cross members, braces, and other large structures will be carefully removed and hauled to appropriate disposal areas. Existing bridge piers at the river’s edge will be carefully broken into pieces that can be loaded and hauled away.
  • The applicant will comply with all stipulations of the Memorandum of Agreement between the Federal Highway Administration and the Tennessee Historic Preservation Officer, regarding Mitigation of Adverse Effects for the State Route 13 Bridge Replacement Project.

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Conclusion and Findings

For compliance with Executive Order 11988, culverts, bridges, the grading, and fill associated with the bridge approach are considered to be repetitive actions in the floodplain for which there is no practicable alternative. The proposed wetland mitigation in the Coffee County Wetland Mitigation Bank is appropriate because there are no suitable on-site mitigation areas. TVA concurs that the special conditions recommended by the USFWS would adequately mitigate the effects to the pygmy madtom. TVA is a concurring party on the MOA (August 12, 2002) between THC and the FHWA, which certified that Section 106 of the National Historic Preservation Act compliance obligations have been met.

TVA has concluded that with the inclusion of standard Section 26a approval conditions, the mitigation measures previously identified that will be included as special conditions in the Section 26a approval, and the commitments contained in the USACE EA, the EA is adequate and the impacts on the environment and agency comments have been adequately addressed. TVA has decided to adopt the USACE EA. It is attached and incorporated by reference.

Based on the EA, we conclude that the Section 26a approvals for the replacement of the SR 13 bridge replacement across the Duck River in Humphreys County would not be a major federal action significantly affecting the environment. Accordingly, an Environmental Impact Statement is not required. This FONSI is contingent upon successful implementation of TVA Standard Conditions (5a-e and 6a-i) and the mitigation measures previously identified.

Original signed by:
Jon M. Loney
Manager, NEPA Administration
Environmental Policy and Planning
Tennessee Valley Authority

Date: January 15, 2003

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