Armstrong Irr. Dam Reservoir Report
Nearby: Sd Noname 285 Sd Noname 286
Last Updated: December 5, 2025
Armstrong Irrigation Dam, located in Haakon County, South Dakota, is a private-owned structure that serves as a critical water resource for the region.
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Summary
Completed in 1974, the earth-type dam stands at a height of 21 feet and has a storage capacity of 125 acre-feet, with a normal storage level of 65 acre-feet. The dam is situated on a tributary of Plum Creek and is regulated by the South Dakota Department of Environment and Natural Resources.
Despite its low hazard potential, the dam's condition assessment is currently not rated, highlighting the need for regular inspections and maintenance to ensure its structural integrity. The dam does not have an Emergency Action Plan (EAP) in place, raising concerns about emergency preparedness and response in the event of a potential failure. With a maximum discharge capacity of 1028 cubic feet per second, it is crucial for the dam to undergo regular monitoring and risk assessment to mitigate any potential threats to downstream communities and the environment.
In addition to providing irrigation water for agricultural purposes, Armstrong Irrigation Dam plays a crucial role in water management and conservation efforts in the region. As a key infrastructure project designed by the Natural Resources Conservation Service, the dam contributes to the overall sustainability of water resources in South Dakota. With its strategic location and historical significance, Armstrong Irrigation Dam remains a vital component of the state's water infrastructure network.
Year Completed |
1974 |
Dam Length |
568 |
Dam Height |
21 |
River Or Stream |
TRIB. PLUM CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
21 |
Nid Storage |
125 |
Hazard Potential |
Low |
Nid Height |
21 |
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.
Armstrong Irr. Dam