Big Lake (Toole) Reservoir Report
Nearby: Alkali (Toole) Him
Last Updated: January 12, 2026
Big Lake in Toole, Montana, is a privately owned reservoir primarily used for irrigation purposes.
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Summary
The earth dam, completed in 1907, stands at a height of 9.1 meters and has a storage capacity of 143 acre-feet. Situated along Fred George and Pete Creek, this reservoir covers approximately 31.5 acres and serves as a vital water resource in the region.
Managed by the Montana Department of Natural Resources and Conservation (DNRC), Big Lake has been deemed to have a low hazard potential with a condition assessment that is currently not rated. Despite its age, the dam has undergone state inspection, permitting, and enforcement to ensure its safety and compliance with regulations. While there are no associated structures and the last inspection date is unknown, the reservoir continues to play a crucial role in providing water for agricultural needs in the area.
With its location in Toole County and the surrounding Montana landscape, Big Lake serves as a testament to the importance of water resources in sustaining agriculture and ecosystems in the region. Climate enthusiasts and water resource experts can appreciate the historical significance and ongoing management efforts of this reservoir in supporting the local community's irrigation needs and contributing to the overall water infrastructure in Montana.
Year Completed |
1907 |
Dam Length |
20 |
Dam Height |
9.1 |
River Or Stream |
FRED GEORGE & PETE CREEK |
Primary Dam Type |
Earth |
Surface Area |
31.5 |
Hydraulic Height |
9.1 |
Nid Storage |
143 |
Hazard Potential |
Low |
Nid Height |
9 |
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.
Big Lake (Toole)