U S A Reservoir Report
Nearby: A. Mosiman W. Day
Last Updated: December 11, 2025
U S A, also known as Winkler Dam, is a federal-owned structure located in South Dakota along the TRIB MEDICINE KNOLL CREEK.
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Summary
Built in 1938, this earth dam stands at a height of 26 feet and stretches 690 feet in length, with a storage capacity of 624 acre-feet. Despite its low hazard potential, the dam has not been rated for its current condition.
Managed by the St. Paul District of the US Army Corps of Engineers, U S A serves as a crucial water resource for the region, providing irrigation and flood control benefits. With a maximum discharge capacity of 3,570 cubic feet per second, the dam plays a vital role in water management in Sully County, South Dakota. However, it is notable that the dam is not regulated by the state and does not have a formal inspection, enforcement, or permitting process in place.
Given its historical significance and importance for local water infrastructure, U S A represents a key piece of the region's water management system. As water resource and climate enthusiasts continue to monitor and advocate for sustainable water practices, understanding the role and condition of structures like U S A will be essential in ensuring the resilience and safety of water resources in South Dakota and beyond.
Year Completed |
1938 |
Dam Length |
690 |
Dam Height |
26 |
River Or Stream |
TRIB MEDICINE KNOLL CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
26 |
Nid Storage |
624 |
Hazard Potential |
Low |
Nid Height |
26 |
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.
U S A