Mincoff #2 Reservoir Report
Nearby: Magnesia Mincoff Reservoir #1
Last Updated: December 6, 2025
Mincoff #2 is a privately owned earth dam located in Cohagen, Montana, along the North Phillips Creek.
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Summary
Built in 1950 by the USDA NRCS, this dam serves multiple purposes including fire protection, stock, and small fish pond management. With a height of 20 feet and a length of 594 feet, this dam has a storage capacity of 317 acre-feet and a drainage area of 5.35 square miles.
Despite being regulated and inspected by the Montana Department of Natural Resources Conservation (DNRC), Mincoff #2 is classified as having a significant hazard potential and a moderate risk level. With a spillway type of 'Uncontrolled' and a maximum discharge of 650 cubic feet per second, this dam poses potential risks to the surrounding area in the event of a breach. However, the condition assessment of Mincoff #2 is currently marked as 'Not Rated', indicating a need for further evaluation and potential risk management measures.
Located in Congressional District 00, Montana, Mincoff #2 is under the jurisdiction of the Omaha District of the US Army Corps of Engineers. With its strategic location and crucial role in water resource management, this dam serves as a vital infrastructure for the local community while also highlighting the importance of proper maintenance and monitoring in the face of changing climate conditions.
Year Completed |
1950 |
Dam Length |
594 |
Dam Height |
20 |
River Or Stream |
NORTH PHILLIPS CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Drainage Area |
5.35 |
Nid Storage |
317 |
Hazard Potential |
Significant |
Nid Height |
20 |
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.
Mincoff #2