Tiber Dike Reservoir Report

Last Updated: December 6, 2025

Tiber Dike, also known as Tiber Reservoir, is a federal-owned structure located in Liberty, Montana, along the Marias River offstream.


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Summary

Built in 1956 by the Bureau of Reclamation, this earth dam stands at a height of 48 feet and has a total length of 18,850 feet. With a maximum storage capacity of 1,424,478 acre-feet and a normal storage capacity of 967,320 acre-feet, Tiber Dike plays a crucial role in water resource management in the region.

Despite its high hazard potential and risk assessment rating of 2 (high), the condition assessment of Tiber Dike is currently marked as "Not Available." Emergency action plans and risk management measures are also not explicitly stated in the available data. The last inspection of the dam was conducted in August 2020, with a scheduled frequency of one inspection per year. As a key infrastructure project managed by the Bureau of Reclamation, Tiber Dike continues to serve as a critical piece of the water management system in Montana, highlighting the intersection of water resources and climate resilience in the region.

Year Completed

1956

Dam Length

18850

Dam Height

48

River Or Stream

MARIAS RIVER OFFSTREAM

Primary Dam Type

Earth

Surface Area

23805

Hydraulic Height

42

Drainage Area

4393

Nid Storage

1424478

Structural Height

65

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

65
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.