Olson No. 2 Reservoir Report
Nearby: Olson No. 1 Rada No. 2
Last Updated: December 8, 2025
Olson No.
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Summary
2 is a privately owned dam located in Mellette, South Dakota, along a tributary of the Big White River. Constructed in 1966 by the Natural Resources Conservation Service, this earth dam stands at 28 feet high with a length of 155 feet, providing a storage capacity of 17 acre-feet. With a maximum discharge capability of 650 cubic feet per second, this low-hazard dam serves important regulatory functions in the state, as it is subject to inspection, permitting, and enforcement by the South Dakota Department of Environment and Natural Resources.
While the condition assessment of Olson No. 2 is currently listed as "Not Rated," the dam's emergency action plan status and risk assessment details are not available. Despite these gaps in information, the dam's low hazard potential suggests that it poses minimal risk to downstream communities. As water resource and climate enthusiasts, understanding the regulatory oversight and operational features of dams like Olson No. 2 is crucial for ensuring the safety and sustainability of our water infrastructure in the face of changing environmental conditions.
Year Completed |
1966 |
Dam Length |
155 |
Dam Height |
28 |
River Or Stream |
TRIB OF BIG WHITE OFF STREAM |
Primary Dam Type |
Earth |
Hydraulic Height |
28 |
Nid Storage |
17 |
Hazard Potential |
Low |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Olson No. 2