Nickajack Dam Reservoir Report

Last Updated: December 5, 2025

Nickajack Dam, located in Marion, Tennessee, along the Tennessee River, is a marvel of engineering that serves multiple essential purposes.


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Summary

Built in 1967 by the Tennessee Valley Authority (TVA), this concrete dam stands at a height of 81 feet and has a hydraulic height of 74 feet. With a storage capacity of 251,600 acre-feet and a maximum discharge of 501,900 cubic feet per second, Nickajack Dam plays a crucial role in hydroelectric power generation, navigation, recreation, and water supply in the region.

The dam's spillway, controlled by a 400-foot wide structure, ensures the safe release of excess water during high-flow periods. Additionally, Nickajack Dam features a single lock with dimensions of 600 feet in length and 110 feet in width, facilitating the passage of vessels through the waterway. Despite its high hazard potential, the dam is regularly inspected by the TVA to ensure its structural integrity and safety.

Nickajack Dam's strategic location in the Tennessee River watershed, combined with its significant storage capacity and multiple functions, underscores its importance in water resource management and climate resilience efforts. As a key component of the TVA's infrastructure, this dam continues to play a vital role in meeting the region's energy needs, supporting navigation activities, providing recreational opportunities, and safeguarding water supplies for local communities.

Years Modified

1992 - Hydraulic, 1992 - Other

Year Completed

1967

Dam Length

3767

Dam Height

81

River Or Stream

TENNESSEE RIVER

Primary Dam Type

Concrete

Surface Area

10200

Length Of Locks

600

Hydraulic Height

74

Drainage Area

21870

Nid Storage

251600

Structural Height

81

Outlet Gates

Tainter (radial)

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

81
       
Seasonal Comparison

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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.