Hanley Reservoir Report
Nearby: Ed Rath #1 Homer #1
Last Updated: December 5, 2025
Hanley is a private irrigation dam located in Ismay, Montana, along Spring Creek.
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Summary
Completed in 1936, this Earth-type dam stands at a height of 15 feet and has a storage capacity of 579 acre-feet. With a primary purpose of irrigation, Hanley serves as a crucial water resource for agricultural activities in the region.
Managed by the DNRC and regulated by the state of Montana, Hanley Dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. Despite its age, the dam remains a reliable infrastructure for water storage and distribution. With state permitting, inspection, and enforcement in place, Hanley continues to play a vital role in water management for the local community.
Situated in Carter County, Montana, Hanley Dam is under the jurisdiction of Congressional District 00, represented by Greg Gianforte. With its strategic location and historical significance, Hanley stands as a testament to the importance of sustainable water resource management in the face of changing climate patterns. Enthusiasts of water resources and climate resilience can appreciate the role that Hanley plays in supporting agricultural activities and ensuring water security in the region.
Year Completed |
1936 |
Dam Length |
504 |
Dam Height |
15 |
River Or Stream |
SPRING CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Nid Storage |
579 |
Hazard Potential |
Low |
Nid Height |
15 |
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.
Hanley