Lost Calf Detention Dam Reservoir Report
Nearby: Helen B Dent Dam Helen B
Last Updated: December 5, 2025
Lost Calf Detention Dam, located in Carter, Montana, was completed in 1966 by the Bureau of Land Management for fire protection, stock, and as a small fish pond.
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Summary
The gravity dam stands at a structural height of 31 feet with a hydraulic height of 27 feet, spanning 1824 feet in length and holding a storage capacity of 653 acre-feet. Situated on the Boxelder Creek/Little Missouri River, the dam serves as a crucial resource for water management in the area.
Despite its low hazard potential, the dam's condition assessment currently stands as unsatisfactory, prompting a moderate risk assessment. Although the dam has not been modified in recent years, the Bureau of Land Management conducts inspections every five years to monitor its safety and structural integrity. With a spillway type of uncontrolled and a spillway width of 3 feet, the Lost Calf Detention Dam remains an essential structure for water resource management in the region, ensuring adequate water supply for various purposes while mitigating potential risks.
Year Completed |
1966 |
Dam Length |
1824 |
River Or Stream |
BOXELDER CK./LITTLE MISSOURI R |
Primary Dam Type |
Gravity |
Surface Area |
83.72 |
Hydraulic Height |
27 |
Nid Storage |
653 |
Structural Height |
31 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
31 |
Seasonal Comparison
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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.
Lost Calf Detention Dam