Twin (Turtle) Lake Reservoir Report
Nearby: Hell Roaring Pablo
Last Updated: December 5, 2025
Twin (Turtle) Lake in Montana, managed by the Bureau of Indian Affairs, is a picturesque body of water fed by a feeder canal.
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Summary
Built in 1932, this Earth dam stands at a structural height of 39 feet and spans 1200 feet in length, providing a storage capacity of 1200 acre-feet. The spillway, a Controlled type, ensures the safe release of excess water.
Despite its age, Twin (Turtle) Lake faces a high hazard potential due to its condition being listed as "Not Available." The Emergency Action Plan (EAP) was last revised in 2015, indicating a need for updated risk assessment and management measures. With a risk assessment rating of "Very High (1)," there is a pressing need for proactive measures to ensure the safety and integrity of this essential water resource.
Enthusiasts of water resources and climate will be drawn to Twin (Turtle) Lake for its historical significance and ecological importance. The lake's location in Lake County, Montana, provides a unique opportunity for research and conservation efforts, highlighting the interconnectedness of water resources and climate dynamics in the region.
Year Completed |
1932 |
Dam Length |
1200 |
River Or Stream |
FEEDER CANAL |
Primary Dam Type |
Earth |
Nid Storage |
1200 |
Structural Height |
39 |
Hazard Potential |
High |
Nid Height |
39 |
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.
Twin (Turtle) Lake
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