Oswarld Number 2 Reservoir Report
Nearby: Oswald No. 1 Jarl No.1
Last Updated: December 8, 2025
Oswarld Number 2 is a privately owned dam located in Mellette, South Dakota, along a tributary of Cotton Wood Creek.
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Summary
Built in 1964, the earth dam stands at a height of 27 feet and has a storage capacity of 90 acre-feet. With a maximum discharge of 2250 cubic feet per second, the dam serves the primary purpose of water resource management and flood control in the area.
Managed by the Natural Resources Conservation Service, Oswarld Number 2 is regulated by the South Dakota Department of Environment and Natural Resources, with state jurisdiction and permitting in place. Despite being rated as having a low hazard potential, the dam's condition has not been formally assessed. It is important for water resource and climate enthusiasts to monitor the maintenance and inspection of dams like Oswarld Number 2 to ensure the safety and functionality of these critical infrastructure assets in the face of changing environmental conditions.
Overall, Oswarld Number 2 plays a vital role in water management and flood control efforts in the region, highlighting the importance of proper regulation and oversight for infrastructure projects. As climate change continues to impact water resources, it is essential for stakeholders to stay informed and engaged in the preservation and sustainable management of these valuable assets for the benefit of both communities and the environment.
Year Completed |
1964 |
Dam Length |
860 |
Dam Height |
27 |
River Or Stream |
TRIB OF COTTON WOOD CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
27 |
Nid Storage |
90 |
Hazard Potential |
Low |
Nid Height |
27 |
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.
Oswarld Number 2