Magnuson Number 1 Reservoir Report
Nearby: Dalhke Number 7 Chambliss Number 3
Last Updated: December 13, 2025
Magnuson Number 1, located in Fort Pierre, South Dakota, is a privately owned earth dam that was completed in 1955.
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Summary
With a height of 28 feet and a length of 366 feet, this dam serves the primary purpose of water conservation and flood control along the TR-Bad River. Managed by the Natural Resources Conservation Service, Magnuson Number 1 has a storage capacity of 34 acre-feet and a maximum discharge of 750 cubic feet per second.
Despite being classified as having a low hazard potential, Magnuson Number 1 is regulated by the South Dakota Department of Environment and Natural Resources, with state jurisdiction and permitting in place for inspections and enforcement. The dam has not been rated for its condition assessment, and emergency action plans are not currently prepared or updated. While the dam has not undergone recent modifications, there are no associated structures or locks in place. Overall, Magnuson Number 1 plays a crucial role in water resource management in the region, contributing to the stability and sustainability of the local ecosystem.
Year Completed |
1955 |
Dam Length |
366 |
Dam Height |
28 |
River Or Stream |
TR-BAD RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
28 |
Nid Storage |
34 |
Hazard Potential |
Low |
Nid Height |
28 |
Seasonal Comparison
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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.
Magnuson Number 1