Bar Island Detention Dam Reservoir Report
Last Updated: December 5, 2025
Bar Island Detention Dam, located in Phillips County, Montana, serves as a crucial flood risk reduction structure along the Rock Creek and Missouri River.
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Summary
Constructed in 1967 by the Bureau of Land Management, this gravity dam stands at a structural height of 44 feet and has a hydraulic height of 37 feet. With a storage capacity of 484.38 acre-feet and a surface area of 27.6 acres, the dam plays a significant role in managing water flow and mitigating potential flood hazards in the region.
Despite its importance in safeguarding the surrounding areas from flooding, Bar Island Detention Dam is rated as having a low hazard potential with a poor condition assessment. The dam, primarily funded, designed, and regulated by the Bureau of Land Management, is in need of inspection and maintenance to ensure its continued effectiveness in flood risk reduction. With a moderate risk assessment rating, it is imperative that necessary risk management measures be implemented to uphold the dam's structural integrity and functionality for the protection of the local community and environment.
As water resource and climate enthusiasts monitor the state of Bar Island Detention Dam, it is crucial for federal agencies and stakeholders to prioritize its inspection and maintenance. By addressing the dam's condition and implementing appropriate risk management measures, the structure can continue to play a vital role in flood risk reduction for Phillips County and the surrounding areas along the Rock Creek and Missouri River. The collaboration between the Bureau of Land Management and other relevant agencies is essential in ensuring the long-term resilience of this important water infrastructure.
Year Completed |
1967 |
Dam Length |
597 |
River Or Stream |
ROCK CK./MISSOURI RIVER |
Primary Dam Type |
Gravity |
Surface Area |
27.6 |
Hydraulic Height |
37 |
Drainage Area |
13.2 |
Nid Storage |
484.38 |
Structural Height |
44 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
44 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Missouri River Near Landusky Mt
|
9100cfs |
Peoples Creek Near Hays Mt
|
4cfs |
Milk River Near Dodson Mt
|
68cfs |
Judith River Nr Mouth
|
368cfs |
Milk River Near Harlem Mt
|
69cfs |
Milk River At Malta Mt
|
0cfs |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
James Kipp Recreation Area - UMRBNM
|
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JAMES KIPP RECREATION AREA
|
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James Kipp
|
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Montana Gulch
|
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MONTANA GULCH CAMPGROUND
|
Bar Island Detention Dam