Agate Flat Dam Reservoir Report
Nearby: Homestead Retention Dam Schwartz
Last Updated: December 6, 2025
Agate Flat Dam, located in Prairie, Montana, is a gravity dam managed by the Bureau of Land Management.
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Summary
It stands at a hydraulic height of 27 feet and a structural height of 32 feet, with a length of 1331 feet. The dam has a storage capacity of 183.5 acre-feet, with a normal storage capacity of 41.96 acre-feet. While it has a low hazard potential, its condition assessment is rated as satisfactory.
The dam, constructed by the Bureau of Land Management, serves the primary purpose of water storage. It features an uncontrolled spillway with a width of 3 feet and is associated with an unnamed drainage. The risk assessment for Agate Flat Dam is moderate, indicating a need for ongoing monitoring and management measures. The last inspection took place in September 2018, with a scheduled inspection frequency of 5 years.
For water resource and climate enthusiasts, Agate Flat Dam presents an intriguing case study in dam management and risk assessment. Its location in Montana, along with its design features and storage capacity, make it a valuable asset for the management of water resources in the region. Continued monitoring and maintenance will be essential to ensure the dam's continued safety and functionality in the face of evolving climate conditions.
Dam Length |
1331 |
River Or Stream |
UNNAMED DRAINAGE |
Primary Dam Type |
Gravity |
Surface Area |
27 |
Hydraulic Height |
27 |
Drainage Area |
7 |
Nid Storage |
183.5 |
Structural Height |
32 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
32 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Redwater River At Circle Mt
|
1cfs |
Yellowstone River At Glendive Mt
|
6000cfs |
Nelson Creek Near Van Norman Mt
|
33cfs |
Yellowstone River At Miles City Mt
|
8100cfs |
Powder River Near Locate Mt
|
231cfs |
Tongue River At Miles City Mt
|
263cfs |
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.
Agate Flat Dam