B. Oleary Reservoir Report
Nearby: Oleary Oleary Ranch 1
Last Updated: December 12, 2025
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Summary
Oleary, a privately owned dam located in Dewey, South Dakota, stands as a testament to water resource management in the region. Constructed in 1945, this earth dam spans 500 feet in length and reaches a height of 18 feet, with a storage capacity of 54 acre-feet. The dam regulates the flow of the TR MOREAU river, providing essential water management functions for the area.
Managed by the South Dakota Department of Environment and Natural Resources (DENR), B. Oleary is classified as a low hazard potential structure with a condition assessment of "Not Rated." While the dam has not been inspected recently, it is equipped with state-regulated permitting, inspection, and enforcement measures to ensure its safe operation. Despite its age, B. Oleary continues to fulfill its intended purpose, contributing to the overall water resource management efforts in the region.
With its historical significance and ongoing role in water management, B. Oleary serves as a noteworthy example of sustainable infrastructure in South Dakota. As climate change impacts water resources worldwide, structures like B. Oleary play a vital role in mitigating risks and ensuring water security for communities. Enthusiasts of water resources and climate resilience can appreciate B. Oleary's importance in the broader context of sustainable water management practices.
Year Completed |
1945 |
Dam Length |
500 |
Dam Height |
18 |
River Or Stream |
TR MOREAU |
Primary Dam Type |
Earth |
Hydraulic Height |
18 |
Nid Storage |
54 |
Hazard Potential |
Low |
Nid Height |
18 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Moreau R Near Whitehorse Sd
|
35cfs |
Grand R At Little Eagle Sd
|
47cfs |
Oak Cr Near Wakpala Sd
|
10cfs |
Moreau R Near Faith Sd
|
14cfs |
Cedar Creek Nr Raleigh
|
20cfs |
Cannonball River Nr Raleigh
|
40cfs |
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.
B. Oleary