Johnson Lake Dam Reservoir Report
Last Updated: December 15, 2025
Johnson Lake Dam, located in Aiken, South Carolina, is a privately owned structure that serves multiple purposes, including recreation and other activities.
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Summary
Completed in 1958, this earth dam stands at a height of 15 feet and spans a length of 525 feet, with a storage capacity of 99 acre-feet. The dam is situated on Bradley Mill Branch and is regulated by the South Carolina Department of Health and Environmental Control (DHEC).
Despite being classified as having a low hazard potential, the dam's condition assessment was rated as poor during its last inspection in August 2017. The inspection frequency is set at every five years, highlighting the need for regular monitoring and maintenance to ensure the safety and integrity of the structure. With a history of modification and a designated emergency action plan, Johnson Lake Dam remains a vital component of water resource management in the area.
As an enthusiast of water resources and climate, the Johnson Lake Dam presents an intriguing case study in dam management and maintenance. Its history, design characteristics, and current condition offer valuable insights into the challenges and responsibilities associated with ensuring the safety and functionality of essential infrastructure in the face of changing environmental conditions.
Year Completed |
1958 |
Dam Length |
525 |
Dam Height |
15 |
River Or Stream |
BRADLEY MILL BRANCH |
Primary Dam Type |
Earth |
Surface Area |
20 |
Nid Storage |
99 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
15 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Mctier Creek (Rd 209) Near Monetta
|
10cfs |
Augusta Canal Nr Augusta (Upper)
|
1850cfs |
Savannah River At Augusta
|
3140cfs |
Butler Creek Below 7th Avenue
|
7cfs |
Stevens Creek Near Modoc
|
61cfs |
Spirit Creek At Us 1
|
10cfs |
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.
Johnson Lake Dam