Ninetynine Island Reservoir Below Cherokee Falls Reservoir Report

Last Updated: December 5, 2025

Ninetynine Island Reservoir is a man-made lake located below Cherokee Falls in South Carolina.


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Summary

The reservoir was constructed in the early 1900s to provide hydroelectric power to the surrounding area. The hydrology of Ninetynine Island Reservoir is primarily fed by the Broad River, which flows into the lake from the north. The lake also receives water from several smaller tributaries, as well as from snowpack melt during the winter months. The lake serves as a water source for agricultural irrigation and recreational activities such as fishing, boating, and swimming. The surrounding area is rich in history and culture, with several museums and historic sites in the vicinity. Overall, Ninetynine Island Reservoir is an important resource for the community, providing both economic and recreational benefits.

Reservoir Details

Elevation Of Reservoir Water Surface Above Datum, Ft 24hr Change -0.08%
Percent of Normal 100%
Minimum 94.73 ft
2017-11-01
Maximum 109.5 ft
2022-12-28
Average 100 ft
Dam_Height 72
Drainage_Area 1550
Year_Completed 1909
Nid_Storage 2300
Structural_Height 72
River_Or_Stream Broad
Foundations Rock
Surface_Area 350
Hazard_Potential High
Dam_Length 1568
Primary_Dam_Type Concrete
Nid_Height 72
       
Seasonal Comparison
Elevation Of Reservoir Water Surface Above Datum, Ft Levels

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.