Jlwannamaker Dam 1 Reservoir Report
Nearby: Jlwannamaker Dam 2 Buyck Pond Dam
Last Updated: December 6, 2025
Jlwannamaker Dam 1, located in Calhoun, South Carolina, is a privately owned structure that serves primarily for recreational purposes.
°F
°F
mph
Wind
%
Humidity
Summary
Built in 1930, this earth dam stands at 26 feet tall and spans 360 feet in length, with a storage capacity of 54 acre-feet. Despite its low hazard potential, the dam is currently assessed to be in poor condition as of the last inspection in 2017.
Managed by the South Carolina Department of Health and Environmental Control, Jlwannamaker Dam 1 overlooks the Speigner Branch and is under state jurisdiction, with permitting, inspection, and enforcement processes in place. The dam's uncontrolled spillway and buttress core type contribute to its moderate risk level, calling for potential risk management measures to ensure its safety and stability. With a risk assessment score of 3, it is important for water resource and climate enthusiasts to monitor the condition of this dam for any necessary maintenance or improvements in the future.
Year Completed |
1930 |
Dam Length |
360 |
Dam Height |
26 |
River Or Stream |
SPEIGNER BRANCH |
Primary Dam Type |
Earth |
Surface Area |
5 |
Nid Storage |
54 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Wateree R. Bl Eastover
|
2400cfs |
North Fork Edisto River At Orangeburg
|
950cfs |
Gills Creek At Columbia
|
76cfs |
Congaree River At Columbia
|
4580cfs |
Smith Branch At North Main St At Columbia
|
9cfs |
Saluda River Near Columbia
|
770cfs |
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.
Jlwannamaker Dam 1