Oleary Ranch 1 Reservoir Report
Nearby: Oleary Oleary Ranch 2
Last Updated: December 13, 2025
Oleary Ranch 1 is a privately-owned earth dam located in Dewey, South Dakota, along the TR-MOREAU river.
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Summary
Constructed in 1969 by the Natural Resources Conservation Service, this dam stands at a height of 31 feet and stretches 220 feet in length, providing a storage capacity of 35 acre-feet. With a low hazard potential and a condition assessment of "Not Rated," this dam serves as a crucial water resource infrastructure in the region.
Despite being state regulated and permitted, Oleary Ranch 1 has not undergone recent inspections or assessments. However, its emergency action plan status and risk management measures remain unknown. Being located in a rural area with limited population at risk, the dam's primary purpose and associated structures are unspecified, making it a noteworthy but enigmatic piece of climate resilience infrastructure in the region.
As water resource and climate enthusiasts, the data surrounding Oleary Ranch 1 presents a compelling narrative of a privately-owned dam with a rich history dating back to the late 1960s. Its location along the TR-MOREAU river and its low hazard potential raise questions about its current state of readiness and emergency preparedness, warranting further investigation and attention from regulatory agencies to ensure its continued safety and functionality in the face of changing climate conditions.
Year Completed |
1969 |
Dam Length |
220 |
Dam Height |
31 |
River Or Stream |
TR-MOREAU |
Primary Dam Type |
Earth |
Hydraulic Height |
31 |
Nid Storage |
35 |
Hazard Potential |
Low |
Nid Height |
31 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Moreau R Near Whitehorse Sd
|
35cfs |
Grand R At Little Eagle Sd
|
47cfs |
Moreau R Near Faith Sd
|
14cfs |
Oak Cr Near Wakpala Sd
|
10cfs |
Cheyenne R Near Plainview Sd
|
0cfs |
Cedar Creek Nr Raleigh
|
20cfs |
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.
Oleary Ranch 1