Helen Mccollough Dam Reservoir Report
Last Updated: December 14, 2025
Helen Mccollough Dam, located in Williamsburg, South Carolina, was completed in 1960 and stands at a height of 18 feet with a length of 630 feet.
°F
°F
mph
Wind
%
Humidity
Summary
The dam primarily serves a recreational purpose, offering a storage capacity of 73 acre-feet and a normal storage of 29 acre-feet. Situated on the TR-OX SWAMP river/stream, this earth dam with a buttress core type has been regulated, permitted, inspected, and enforced by the South Carolina Department of Health and Environmental Control (SC DHEC).
Despite its low hazard potential, the dam's condition assessment was reported as poor during its last inspection in November 2017. With an inspection frequency of 5 years, there is a need for improved maintenance and potentially a condition assessment update to ensure the safety and integrity of the structure. Furthermore, the dam lacks emergency action preparedness, inundation maps, and risk assessment measures, highlighting areas for improvement in emergency response planning and risk management.
For water resource and climate enthusiasts, Helen Mccollough Dam presents an opportunity for further study and advocacy for proper maintenance, monitoring, and emergency preparedness. As a privately owned structure under state regulation, there is a need for collaboration between the owner, regulatory agencies, and the community to address the poor condition assessment and implement necessary risk management measures. By enhancing the safety and resilience of the dam, its recreational benefits can be sustained while mitigating potential hazards and ensuring the protection of downstream areas.
Year Completed |
1960 |
Dam Length |
630 |
Dam Height |
18 |
River Or Stream |
TR-OX SWAMP |
Primary Dam Type |
Earth |
Surface Area |
12 |
Nid Storage |
73 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
18 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Black River At Kingstree
|
1280cfs |
Santee River Nr Jamestown
|
1170cfs |
Santee River Near Pineville
|
676cfs |
Lake Moultrie Tailrace Canal At Moncks Corner
|
9370cfs |
Turkey Creek Near Maryville
|
2cfs |
Pee Dee River At Hwy 701 Nr Bucksport
|
8500cfs |
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.
Helen Mccollough Dam