Ambrose Reservoir Report
Nearby: Stephan Mission Stephen Mission
Last Updated: December 13, 2025
Ambrose is a federal recreational dam located in South Dakota, specifically in Hyde County.
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Summary
Built in 1935, this Earth-type dam stands at a structural height of 25 feet and spans 800 feet along the West Fork Elm Creek. Managed by the Bureau of Indian Affairs, Ambrose provides a storage capacity of 500 acre-feet for recreational purposes. Despite being classified as having a high hazard potential, the condition assessment of the dam is currently listed as "Not Available".
Owned, funded, designed, and regulated by the Bureau of Indian Affairs, Ambrose serves as a vital water resource for the community of Stephan. The dam is situated within the DOI BIA's jurisdiction and is not subject to state regulation, permitting, or inspection. Although the last inspection date was in 2012, with an inspection frequency of 5 years, the Emergency Action Plan status and risk assessment information for Ambrose are currently unavailable.
As an integral part of the St. Paul District's water infrastructure, Ambrose stands as a testament to the intersection of water resource management and recreational activities in the region. Climate and water resource enthusiasts are drawn to the unique features of this dam, which not only provides recreational opportunities but also serves as a crucial component of the local ecosystem.
Year Completed |
1935 |
Dam Length |
800 |
River Or Stream |
WEST FORK ELM CREEK |
Primary Dam Type |
Earth |
Nid Storage |
500 |
Structural Height |
25 |
Hazard Potential |
High |
Nid Height |
25 |
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.
Ambrose