Stephan Mission Reservoir Report
Nearby: Ambrose Stephen Mission
Last Updated: December 13, 2025
Stephan Mission, located in South Dakota along the West Fork Elm Creek, serves as a vital water supply source for the local community.
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Summary
Constructed in 1937, this earth dam stands at a height of 19 feet and spans a length of 625 feet, with a storage capacity of 288 acre-feet. Its primary purpose includes providing water for fire protection, livestock, and small fish ponds, in addition to meeting the water supply needs of the region.
Managed by the Tribal Government, Stephan Mission has a low hazard potential and is currently rated as "Not Rated" in terms of its condition assessment. While it is not regulated by the state and does not have a state jurisdiction, the dam plays a crucial role in ensuring water availability for various purposes. With a maximum discharge capacity of 875 cubic feet per second, this structure contributes to the overall water management efforts in the area.
Despite not being under the purview of a regulatory agency, Stephan Mission continues to fulfill its intended functions effectively. As a significant water resource in Hyde County, South Dakota, this dam underscores the importance of sustainable water infrastructure for supporting community needs and climate resilience in the region.
Year Completed |
1937 |
Dam Length |
625 |
Dam Height |
19 |
River Or Stream |
WEST FORK ELM CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
19 |
Nid Storage |
288 |
Structural Height |
19 |
Hazard Potential |
Low |
Nid Height |
19 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
White R Near Oacoma Sd
|
105cfs |
Bad R Near Fort Pierre Sd
|
7cfs |
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.
Stephan Mission