Environmental Assessment - Tennessee Valley Authority

The third phase is a 24-inch-diameter finished water line crossing the Tennessee River at
TRM 591.6L (see Figure 1). The river crossing is being proposed to replace the former
water line that was on the old US 11 bridge, which was demolished and replaced in 2003.
The new US 11 bridge is not capable of supporting a 24-inch water line. The water line
would be trenched 3 feet deep, down each bank to elevation 721 feet and properly
anchored to the river bottom for the remainder of the crossing. The top of all anchors would
be below 721 feet elevation. The pipe used in the river crossing would consist of Class 250
cement-lined ductile iron ball joint pipe. The pipe is designed to provide a deflection angle
of 15 degrees.
Section 26a of the Tennessee Valley Authority Act, requires that TVA approval be obtained
prior to the construction, operation, or maintenance of a structure or construction activity
affecting navigation, flood control, or public lands. Therefore TVA’s action would be to
make a decision on the Section 26a approval request for the construction of a new 20-MGD
water intake and 48-inch raw water pipeline at the Loudon Utilities WTP and crossing of the
Tennessee River by a 24-inch-diameter water line under Section 26a of the TVA Act. To
address the potential environmental impacts of the proposal, TVA has agreed to be the lead
agency cooperating with the United States Army Corps of Engineers (USACE) in the
preparation of this environmental assessment (EA). USACE’s action would be to approve
the project under Section 10 of the Rivers and Harbors Act and Section 404 of the Clean
Water Act.
Other Environmental Reviews and Documentation
Categorical Exclusion Checklist Number 19649 (TVA 2009b)
On March 13, 2009, TVA completed an environmental review and approved Phase 1 of the
proposed LUB water intake and pipeline project to repair and maintain the existing water
pipeline and intake (see Attachment B).
Section 26a Approval for Tennessee State Route 2 (US 11) Bridge Over the Tennessee
River Environmental Assessment and Finding of No Significant Impact (FONSI) (TVA 2002)
In April 2002, TVA completed an EA and FONSI for the replacement of the US 11 bridge
over the Tennessee River at TRM 591.6 near Loudon, Tennessee. Under the Preferred
Alternative to construct a new bridge, there was the potential to kill or harm individuals of
the endangered pink mucket and orangefoot pimpleback mussels. Commitments and
additional requirements from the United States Fish and Wildlife Service (USFWS) revised
biological opinion (BO) reduced all impacts to the aquatic animals to insignificant levels. In
addition, a memorandum of agreement between the Tennessee State Historic Preservation
Officer (SHPO), the Tennessee Department of Transportation, Federal Highway
Administration, Tennessee Department of Environment and Conservation (TDEC), and the
Eastern Band of the Cherokee Indians ensured the recovery and preservation of any
archaeological information from an archaeological site that would be adversely affected by
the proposed project. The bridge has been successfully constructed with the application of
the conditions and mitigation and is currently in service.
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