Nolichucky Dam Gate Replacement Project

The Tennessee Valley Authority (TVA) has issued a final Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) to replace the spillway gate on the Nolichucky Dam in Green County, Tennessee.  TVA has chosen Alternative B2 – Replace the Existing Gate and No Dredging in the Nolichucky Reservoir as it’s preferred alternative.

The Nolichucky Dam is a decommissioned hydroelectric facility owned and maintained by TVA. The dam was originally constructed in 1913 as a hydropower facility by the Tennessee Eastern Electric Company to provide power to the surrounding areas. TVA acquired the facility in 1945.

The Nolichucky Dam is a concrete, gravity overflow structure containing two primary water barrier structures – the non-overflow section and the spillway section. In 1972, a 25-foot-wide by 10-foot-high vertical lift gate was constructed in the overflow spillway to permit limited drawdowns of the reservoir. In 1995, the gate opening was sealed with a reinforced concrete bulkhead upstream of the gate. Electrical power and the gate motor were removed at that time.

In the current condition, there is no active means of controlling the reservoir’s water level. TVA considered alternatives to replace the spillway gate to support management of reservoir levels and perform dam safety inspections or investigations within the spillway portion of the dam to support the operation and maintenance of the TVA Reservoir System.

Over time, sediment has built up on the upstream side of the dam. Along with replacing the gate, TVA evaluated options to manage the sediment to support replacement of the gate including: dredging and removal of built up sediment on the upstream side of the dam coupled with land application of the dredged material on-site, or placement of small stone and rip-rap upstream of the dam in the reservoir and on shoreline to control sediment. Based on the results of a sediment transport study, it was determined that the large deposit of sediment built up in the reservoir would not be mobilized by the replacement and normal operation of the spillway gate.

On July 3, 2018, TVA released a draft EA of the proposed spillway gate replacement project for public comment.  The comment period closed on August 3, 2018.  TVA considered the public’s input in finalizing the EA and addresses the comments received the final assessment.