Hoffman Dam Reservoir Report
Nearby: Walt Hoffman No.1 Geigle Dam
Last Updated: December 6, 2025
Hoffman Dam, located in Pennington, South Dakota, is a privately owned earth dam built in 1940 with a height of 20 feet and a length of 360 feet.
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Summary
The dam serves the primary purpose of water storage for the TR-CHEYENNE river system, providing a normal storage capacity of 90 acre-feet and a maximum storage capacity of 230 acre-feet. With a low hazard potential and a condition assessment of "Not Rated," Hoffman Dam plays a crucial role in managing water resources in the region.
Managed by the South Dakota Department of Environmental and Natural Resources (DENR), Hoffman Dam is regulated, permitted, inspected, and enforced by state agencies to ensure its safety and functionality. Despite not being rated for condition assessment, the dam has a solid history of operations and maintenance, with no major modifications or incidents reported. With a maximum discharge capacity of 1800 cubic feet per second, Hoffman Dam is equipped to handle significant water flow during periods of high precipitation or flooding events.
Although lacking in some detailed information such as emergency action plans and risk assessments, Hoffman Dam remains a key infrastructure for water resource management in the region. As climate change continues to impact water availability and extreme weather events, the importance of well-maintained dams like Hoffman Dam becomes increasingly evident. The dam's location within the St. Paul District and its role in the Cheyenne river system highlight its significance in sustaining water resources for the surrounding communities and ecosystems.
Year Completed |
1940 |
Dam Length |
360 |
Dam Height |
20 |
River Or Stream |
TR-CHEYENNE |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Nid Storage |
230 |
Hazard Potential |
Low |
Nid Height |
20 |
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.
Hoffman Dam