Marlo Johnson Reservoir Report
Nearby: Morris Jensen Jenson Dam
Last Updated: December 6, 2025
Marlo Johnson is a private dam located in Perkins, South Dakota, with a low hazard potential and a height of 24 feet.
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Summary
Constructed in 1958, this earth dam serves the primary purpose of water resource management along the TR South Grand River. Managed by the South Dakota Department of Environment and Natural Resources, Marlo Johnson is regulated, permitted, inspected, and enforced by state agencies to ensure its safety and compliance with water resource and climate regulations.
With a storage capacity of 67 acre-feet and a normal storage level of 40 acre-feet, Marlo Johnson plays a crucial role in managing water levels and discharge rates in the region. Although its condition assessment is currently not rated, the dam has not undergone any recent modifications and is deemed to have a low hazard potential. The structure is designed and overseen by the Natural Resources Conservation Service, showcasing a collaborative effort between federal and state entities to safeguard water resources and mitigate climate-related risks in the area. Water resource and climate enthusiasts will find Marlo Johnson to be a significant infrastructure contributing to sustainable water management practices in South Dakota.
Year Completed |
1958 |
Dam Length |
300 |
Dam Height |
24 |
River Or Stream |
TR SOUTH GRAND RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
24 |
Nid Storage |
67 |
Hazard Potential |
Low |
Nid Height |
24 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Marlo Johnson