Little Moreau #3 Reservoir Report
Nearby: Little Moreau #1 Vern Long
Last Updated: December 13, 2025
Little Moreau #3 is a state-regulated earth dam located in Dewey, South Dakota, along a tributary of the Little Moreau River.
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Summary
Constructed in 1960, this dam stands at a height of 18 feet and has a storage capacity of 72 acre-feet. With a low hazard potential and a condition assessment that is currently not rated, this dam serves as a vital water resource management structure for the region.
Owned and regulated by the South Dakota Department of Agriculture and Natural Resources, Little Moreau #3 undergoes regular inspections every three years to ensure its safety and functionality. The dam's emergency action plan status, risk assessment, and risk management measures are currently not available, indicating a potential area for improvement in terms of disaster preparedness and mitigation. Despite its modest size and low hazard potential, the dam plays a crucial role in water storage and flood control efforts in the region.
For water resource and climate enthusiasts, Little Moreau #3 presents an intriguing case study in state-level dam management and infrastructure resilience. As climate change continues to impact water resources and weather patterns, the maintenance and monitoring of structures like Little Moreau #3 will be essential in ensuring the safety and sustainability of water systems in South Dakota and beyond.
Year Completed |
1960 |
Dam Length |
300 |
Dam Height |
18 |
River Or Stream |
TRIB. LITTLE MOREAU RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
18 |
Nid Storage |
72 |
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.
Little Moreau #3