Colstrip Evaporation Pond Dam Reservoir Report
Last Updated: December 5, 2025
Located in Colstrip, Montana, the Colstrip Evaporation Pond Dam stands as a vital structure managing water resources in the area.
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Summary
Built in 1976, this earth dam towers at a height of 88 feet with a hydraulic height of 70 feet, providing a maximum storage capacity of 3834 acre-feet. The dam serves the primary purpose of water retention and disposal, contributing to the management of the TR-East Fork Armells Creek.
Regulated by the Montana Department of Environmental Quality, the Colstrip Evaporation Pond Dam poses a high hazard potential but maintains a satisfactory condition as of the last assessment in 2015. With a surface area of 35 acres and a drainage area of 0.54 square miles, this critical infrastructure plays a crucial role in water management in the region. The dam's inspection frequency and emergency protocols remain undisclosed, highlighting the importance of ongoing monitoring and maintenance to ensure its continued safety and functionality.
As a key component of water resource management in the area, the Colstrip Evaporation Pond Dam plays a crucial role in flood control and water storage. With its strategic location and significant storage capacity, this earth dam serves as a critical piece of infrastructure in the region, highlighting the importance of ongoing regulatory oversight and maintenance to ensure its continued effectiveness and safety for the surrounding community and environment.
Year Completed |
1976 |
Dam Length |
1840 |
Dam Height |
88 |
River Or Stream |
TR-EAST FORK ARMELLS CREEK |
Primary Dam Type |
Earth |
Surface Area |
35 |
Hydraulic Height |
70 |
Drainage Area |
0.54 |
Nid Storage |
3834 |
Hazard Potential |
High |
Nid Height |
88 |
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.
Colstrip Evaporation Pond Dam