Lee #9 Reservoir Report
Nearby: Vassaus #7 Vassaus #11
Last Updated: December 5, 2025
Lee #9 is a privately owned dam located in Colstrip, Montana, along the Mc Gilvrey Creek.
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Summary
Built in 1963, this earth-type dam stands at 20 feet high and spans 350 feet in length, providing essential functions for fire protection, stock watering, and small fish pond maintenance. With a storage capacity of 77 acre-feet, the dam is regulated by the Montana Department of Natural Resources and Conservation (DNRC) and is inspected regularly to ensure its structural integrity.
Despite being categorized as having a low hazard potential, Lee #9 has not been rated for its current condition. The dam has not undergone any recent modifications, and there is no Emergency Action Plan (EAP) in place. While the dam serves important purposes for the local community, such as providing water for firefighting and livestock, there are no specific risk management measures identified for potential emergencies or incidents. The lack of recent assessments and preparedness plans raises questions about the long-term sustainability and safety of this essential water resource infrastructure.
As water resource and climate enthusiasts continue to monitor and advocate for the sustainable management of dams like Lee #9, it is crucial to ensure that regulatory agencies like the DNRC prioritize regular inspections and assessments to maintain the structural integrity of these critical structures. With the potential impacts of climate change on water resources becoming increasingly evident, it is essential to address any vulnerabilities in dam infrastructure to ensure the safety and security of water sources for both human and environmental needs in the future.
Year Completed |
1963 |
Dam Length |
350 |
Dam Height |
20 |
River Or Stream |
MC GILVREY CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Nid Storage |
77 |
Hazard Potential |
Low |
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.
Lee #9