Hett No.1 Reservoir Report
Nearby: Hett No.2 Gilbert No.2
Last Updated: December 6, 2025
Hett No.1 is a privately owned earth dam located in Harding, South Dakota, along the TR-South Fork Grand River.
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Summary
Built in 1958, this dam stands at a height of 13 feet and has a storage capacity of 60 acre-feet. Despite its low hazard potential, the dam is state-regulated and regularly inspected by the South Dakota Department of Environment and Natural Resources to ensure its safety and compliance with regulatory standards.
Managed by the Natural Resources Conservation Service, Hett No.1 plays a crucial role in water resource management and flood control in the region. With a maximum discharge capacity of 250 cubic feet per second, the dam serves to protect downstream areas from potential flooding events. While its structural condition is currently rated as "Not Rated," the dam's emergency action plan status and risk assessment measures are yet to be determined, highlighting the importance of ongoing monitoring and assessment to safeguard against any unforeseen risks or emergencies.
Situated within the jurisdiction of the Omaha District of the US Army Corps of Engineers, Hett No.1 serves as an important infrastructure for water resource enthusiasts and climate advocates alike. As the dam continues to play a vital role in water storage and flood protection in the region, its ongoing maintenance and regulatory oversight ensure the safety and integrity of this essential water resource structure for the community and environment it serves.
Year Completed |
1958 |
Dam Length |
550 |
Dam Height |
13 |
River Or Stream |
TR-SOUTH FORK GRAND RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
13 |
Nid Storage |
60 |
Hazard Potential |
Low |
Nid Height |
13 |
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.
Hett No.1