Jensen Number 5 Reservoir Report
Nearby: Jensen Number 7 Jensen No. 6
Last Updated: December 8, 2025
Jensen Number 5 is a privately owned earth dam located in Mellette, South Dakota, along the TR Cottonwood Offstream river.
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Summary
Constructed in 1972 by the Natural Resources Conservation Service, this dam stands at 28 feet high and spans 530 feet in length, with a storage capacity of 28 acre-feet. Despite being state-regulated and inspected, its hazard potential is rated as low, and its condition assessment remains unrated.
Managed by the St. Paul District of the US Army Corps of Engineers, Jensen Number 5 plays a crucial role in water resource management within the region. With a maximum discharge capacity of 562 cubic feet per second, this dam serves to mitigate flooding and maintain water levels for agricultural and environmental purposes. Although its emergency action plan status and risk assessment details are currently unavailable, the dam continues to uphold its structural integrity and operational effectiveness.
As a significant infrastructure asset in South Dakota, Jensen Number 5 underscores the importance of sustainable water resource management in the face of changing climate conditions. With its low hazard potential and historical significance, this earth dam stands as a testament to the collaborative efforts of private owners and federal agencies in safeguarding water resources for future generations.
Year Completed |
1972 |
Dam Length |
530 |
Dam Height |
28 |
River Or Stream |
TR COTTONWOOD OFFSTREAM |
Primary Dam Type |
Earth |
Hydraulic Height |
28 |
Nid Storage |
28 |
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.
Jensen Number 5