Steffen Dam Reservoir Report
Nearby: Waterbnot Ratedy Dam Bnot Ratedke
Last Updated: December 13, 2025
Steffen Dam, located in Gregory, South Dakota, is a privately owned earth dam completed in 2007 on the TR NIOBRARA RIVER.
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Summary
With a height of 24 feet and a length of 450 feet, this dam has a storage capacity of 103 acre-feet and a maximum discharge of 675 cubic feet per second. The dam is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is inspected, permitted, and enforced by state agencies to ensure its safety and compliance with regulations.
Although Steffen Dam is classified as having low hazard potential and is currently rated as "Not Rated" in terms of condition assessment, the risk assessment for the dam is moderate. Emergency action plans (EAP) and inundation maps are not currently prepared or updated for the dam, which may present challenges in the event of an emergency. Despite these potential risks, the dam remains a crucial infrastructure for water resource management in the area, providing storage for irrigation, recreation, and flood control purposes.
The designer of Steffen Dam was KONECHNE ENG., and the dam is situated within the St. Paul District of the US Army Corps of Engineers. While the dam serves as a vital water resource structure, its management and maintenance are essential to ensure its continued functionality and safety for the surrounding community and environment. Enthusiasts of water resources and climate change should monitor updates on Steffen Dam to understand its impact on local water management and resilience efforts in South Dakota.
Year Completed |
2007 |
Dam Length |
450 |
Dam Height |
24 |
River Or Stream |
TR NIOBRARA RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
24 |
Drainage Area |
1 |
Nid Storage |
103 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
24 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Platte Creek Near Platte
|
3cfs |
Keya Paha R At Wewela Sd
|
54cfs |
Niobrara River At Mariaville
|
1530cfs |
Long Pine Creek Near Riverview
|
188cfs |
Keya Paha R Near Keyapaha Sd
|
33cfs |
White R Near Oacoma Sd
|
105cfs |
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.
Steffen Dam