South Holston Dam - Bent Branch Auxiliary Spillway Reservoir Report

Last Updated: December 5, 2025

South Holston Dam - Bent Branch Auxiliary Spillway is a vital structure located in Bluff City, Tennessee, along the South Fork Holston River.


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Summary

Built in 1950 by the Tennessee Valley Authority, this concrete dam with a multi-arch core serves the primary purpose of flood risk reduction. With a structural height of 9 feet and a length of 300 feet, the dam plays a crucial role in managing water levels and protecting the surrounding areas from potential flooding.

The Bent Branch Auxiliary Spillway features an uncontrolled spillway type with a width of 300 feet, allowing for a maximum discharge of 43,200 cubic feet per second. While it has a high hazard potential, the risk assessment for this structure is moderate. The dam is not state-regulated and is solely owned, funded, designed, constructed, regulated, inspected, and operated by the Tennessee Valley Authority, highlighting the agency's comprehensive involvement in its management and maintenance.

Despite limited data on storage capacity and condition assessment, the South Holston Dam - Bent Branch Auxiliary Spillway continues to play a crucial role in safeguarding the local community and environment from potential flood risks. With regular inspections and emergency action planning in place, this structure stands as a testament to effective water resource management and climate resilience efforts in the region.

Year Completed

1950

Dam Length

300

River Or Stream

SOUTH FORK HOLSTON RIVER

Primary Dam Type

Concrete

Structural Height

9

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Rock

Nid Height

9
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.