Two Forks Detention Dam Reservoir Report
Nearby: Chico Flats Forrest Detention Dam
Last Updated: December 21, 2025
Two Forks Detention Dam, located in Montana along Willow Creek/Milk River, was completed in 1956 with a primary purpose of fire protection, stock, or small fish pond.
°F
°F
mph
Wind
%
Humidity
Summary
Owned by the Bureau of Land Management, this gravity dam stands at 24 feet tall with a hydraulic height of 20 feet and a length of 1319 feet. It has a storage capacity of 90.45 acre-feet and a surface area of 20.1 acres, serving as a key structure for water resource management in the region.
Despite its low hazard potential, the dam's condition assessment is rated as poor, highlighting the need for potential maintenance and improvements. The dam is under federal regulation and inspection by the Bureau of Land Management, ensuring its safe operation and compliance with state permitting and enforcement. With a moderate risk assessment score of 3, there are ongoing efforts to assess and manage any potential risks associated with the dam to safeguard the surrounding community and environment. Water resource and climate enthusiasts can appreciate the significance of Two Forks Detention Dam in balancing water management needs for multiple purposes while prioritizing safety and risk mitigation.
Year Completed |
1956 |
Dam Length |
1319 |
River Or Stream |
WILLOW CK./MILK RIVER |
Primary Dam Type |
Gravity |
Surface Area |
20.1 |
Hydraulic Height |
20 |
Drainage Area |
4.1 |
Nid Storage |
90.45 |
Structural Height |
24 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
24 |
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.
Two Forks Detention Dam