Whidby Structnot Ratede 20 Reservoir Report
Nearby: Prokop Dam Sd Noname 147
Last Updated: December 6, 2025
Whidby Structure 20, located in South Dakota along the TR-White River, is a private earth dam with a height of 24 feet and a length of 400 feet.
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Summary
Completed in 1966, this structure has a storage capacity of 128 acre-feet and a maximum discharge of 1050 cubic feet per second. Despite its significant hazard potential, the condition of Whidby Structure 20 is currently not rated, and it is regulated and inspected by the state's Department of Environment and Natural Resources.
Owned privately and designed by the Natural Resources Conservation Service, Whidby Structure 20 plays a vital role in water resource management in Jackson County, South Dakota. While its emergency action plan status and risk assessment details are not provided in the available data, the structure's importance in flood control and water supply for the area cannot be overstated. With its location within the St. Paul District of the US Army Corps of Engineers, Whidby Structure 20 stands as a key component in the region's overall water infrastructure.
As a crucial component of the local water management system, Whidby Structure 20 serves as a critical piece of infrastructure in South Dakota's efforts to mitigate flood risks and ensure water availability for various purposes. With its state-regulated status, inspection protocols, and significant hazard potential, this structure highlights the ongoing challenges and importance of maintaining and monitoring water resources in the face of changing climate conditions. For water resource and climate enthusiasts, Whidby Structure 20 represents a case study in the intersection of infrastructure, regulation, and environmental stewardship.
Year Completed |
1966 |
Dam Length |
400 |
Dam Height |
24 |
River Or Stream |
TR-WHITE RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
24 |
Nid Storage |
128 |
Hazard Potential |
Significant |
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.
Whidby Structnot Ratede 20