Spun Reservoir Report
Nearby: Webb #1 Dry Fork Fairhaven #1
Last Updated: December 5, 2025
Spun is a privately owned earth dam located in Cascade County, Montana, specifically in the city of ULM.
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Summary
Completed in 1960, this dam serves a primary purpose of water supply, with a storage capacity of 248 acre-feet and a normal storage level of 53 acre-feet. Situated on the TR-MISSOURI RIVER, Spun stands at a height of 15 feet and spans 80 feet in length. It is regulated and inspected by the Montana Department of Natural Resources and Conservation (DNRC), ensuring compliance and safety for its significant hazard potential.
The dam's location in a state-regulated jurisdiction, with enforcement and permitting mechanisms in place, highlights the commitment to maintaining its integrity and functionality. Despite being designated as "Not Rated" in terms of condition assessment, Spun remains an essential infrastructure for water resource management in the area. As part of the Walla Walla District, it reflects the collaboration between local and federal agencies to ensure proper operation and oversight, contributing to water security and climate resilience in the region.
For water resource and climate enthusiasts, Spun presents a case study in the intersection of infrastructure, regulation, and environmental stewardship. Its presence on the Missouri River, within the broader context of water management in Montana, underscores the interconnectedness of human-made structures and natural systems. As discussions around water scarcity and climate change intensify, understanding the role of dams like Spun becomes crucial in navigating the complex challenges and opportunities facing water resources in the 21st century.
Year Completed |
1960 |
Dam Length |
80 |
Dam Height |
15 |
River Or Stream |
TR-MISSOURI RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Nid Storage |
248 |
Hazard Potential |
Significant |
Nid Height |
15 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Missouri River At Cascade Mt
|
3110cfs |
Sun River At Simms Mt
|
1620cfs |
Sun River Near Vaughn Mt
|
2680cfs |
Muddy Creek At Vaughn Mt
|
86cfs |
Missouri River Near Ulm Mt
|
3150cfs |
Dearborn River Near Craig Mt
|
40cfs |
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.
Spun