Wannamakers Upper Dam Reservoir Report
Nearby: Crider Pond Dam Otts Pond Dam
Last Updated: December 14, 2025
Wannamakers Upper Dam, also known as the Rupert Ray Johnson Dam, is a private dam located in Calhoun, South Carolina, along the TR-Little Beaver Creek.
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Summary
Completed in 1970, this earth dam stands at a height of 31 feet and stretches 550 feet in length, providing a storage capacity of 90 acre-feet for recreational purposes. Despite its primary purpose being recreational, this dam has a high hazard potential and is currently assessed as being in poor condition as of November 2020.
Situated within the Savannah District, Wannamakers Upper Dam is regulated by the South Carolina Department of Health and Environmental Control (SC DHEC). Although the dam is under state jurisdiction and regularly inspected, with the last assessment conducted in November 2020, its risk assessment is considered moderate. The dam does not feature controlled spillways, locks, or outlet gates, highlighting the importance of monitoring and maintenance to ensure the safety of the surrounding area and water resources in the event of an emergency.
For water resource and climate enthusiasts, Wannamakers Upper Dam presents an intriguing case study of a privately owned structure with significant recreational value but also notable safety concerns. With its location in a high-risk area and a history dating back to the 1970s, the dam serves as a reminder of the importance of ongoing monitoring, risk assessment, and potential management measures to safeguard both the dam itself and the downstream environment. As efforts continue to ensure the dam's integrity and functionality, its unique characteristics and regulatory oversight offer valuable insights into the intersection of water resource management and public safety.
Year Completed |
1970 |
Dam Length |
550 |
Dam Height |
31 |
River Or Stream |
TR-LITTLE BEAVER CREEK |
Primary Dam Type |
Earth |
Surface Area |
6 |
Nid Storage |
90 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
31 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
North Fork Edisto River At Orangeburg
|
581cfs |
Wateree R. Bl Eastover
|
2400cfs |
Gills Creek At Columbia
|
37cfs |
Congaree River At Columbia
|
3140cfs |
Smith Branch At North Main St At Columbia
|
3cfs |
Saluda River Near Columbia
|
907cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Wannamakers Upper Dam