Gmg Reservoir Report
Last Updated: December 5, 2025
Gmg is a private water resource located in Cascade, Montana, with a primary purpose of providing fire protection, stock water, and serving as a small fish pond.
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Summary
Completed in 1960, this earth dam stands at a height of 20 feet and has a storage capacity of 62 acre-feet. Situated along the Dry Fork Little Muddy Creek, Gmg plays a crucial role in water management and conservation efforts in the area.
Managed by the Montana Department of Natural Resources and Conservation (DNRC), Gmg is regulated, inspected, and enforced to ensure its safe operation. With a low hazard potential and a current condition assessment of "Not Rated," this water resource is a valuable asset for the local community. While the dam has not been modified in recent years, it continues to serve its intended purposes effectively.
Despite not being rated, Gmg poses a low risk and does not currently have an Emergency Action Plan (EAP) in place. However, it meets state permitting and inspection requirements, indicating a commitment to ensuring the safety and functionality of the structure. As climate change impacts water resources, Gmg serves as a vital component in the overall water management strategy for the region, highlighting the importance of sustainable infrastructure in the face of evolving environmental challenges.
Year Completed |
1960 |
Dam Length |
300 |
Dam Height |
20 |
River Or Stream |
DRY FORK LITTLE MUDDY CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Nid Storage |
62 |
Hazard Potential |
Low |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Sun River Near Vaughn Mt
|
2680cfs |
Muddy Creek At Vaughn Mt
|
86cfs |
Sun River At Simms Mt
|
1620cfs |
Missouri River At Cascade Mt
|
3090cfs |
Missouri River Near Ulm Mt
|
3160cfs |
Lake Creek Near Power Mt
|
30cfs |
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.
Gmg