Alcorn Reservoir Report
Nearby: Haivala #2 Sd Noname 132
Last Updated: December 6, 2025
Alcorn is a private dam located in Harding, South Dakota, along the TRIB-S FORK GRAND RIVER.
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Summary
Built in 1951, this earth dam stands at a height of 15 feet and has a length of 1000 feet, providing a storage capacity of 104 acre-feet. Managed by the Natural Resources Conservation Service, Alcorn is regulated by the state agency DENR and undergoes regular inspections, with a low hazard potential and a condition assessment of "Not Rated."
Despite its modest size and low hazard potential, Alcorn plays a crucial role in water resource management in the area. With a normal storage capacity of 84 acre-feet and a maximum discharge of 1470 cubic feet per second, this dam helps control water flow and ensure a stable water supply for the surrounding region. While not currently rated for its condition, the dam's presence highlights the importance of maintaining and monitoring water infrastructure to mitigate potential risks and ensure the safety of communities downstream.
As a part of the Omaha District, Alcorn serves as a reminder of the interconnectedness of water resources and climate resilience. With the potential for future modifications and improvements, this dam represents a key piece of infrastructure in South Dakota's water management strategy, showcasing the ongoing efforts to balance development with environmental conservation and safety considerations.
Year Completed |
1951 |
Dam Length |
1000 |
Dam Height |
15 |
River Or Stream |
TRIB-S FORK GRAND RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Nid Storage |
104 |
Hazard Potential |
Low |
Nid Height |
15 |
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.
Alcorn