Fort Peck Dam Reservoir Report

Last Updated: December 19, 2025

Fort Peck Dam, located in Montana on the Missouri River, is a critical structure managed by the US Army Corps of Engineers for flood risk reduction, hydroelectric power generation, irrigation, navigation, and recreation.


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Summary

Completed in 1940, the dam stands at a structural height of 256 feet and has a storage capacity of 19 million acre-feet. Despite its reliable flood reduction capabilities, the dam faces a high hazard potential due to the risk of overtopping during extreme flood events.

USACE continuously assesses and implements risk management measures to ensure the safety and integrity of Fort Peck Dam. Ongoing actions include regular monitoring, maintenance, and collaboration with local emergency management agencies to enhance preparedness and public awareness of flood risks. Following the 2011 flooding, additional drains and instrumentation were installed, and repairs were made to the spillway to improve resilience during future flood events.

Communities downstream of Fort Peck Dam are advised to stay informed about National Weather Service flood forecasts and have evacuation plans in place for potential flood impacts. It is crucial for residents to understand the risks associated with living near a major dam and take proactive measures to reduce individual risks during flood events. For more information on water management in the Missouri River basin and the USACE Dam Safety Program, visit their official websites.

Year Completed

1940

Dam Length

21026

River Or Stream

MISSOURI RIVER

Primary Dam Type

Earth

Surface Area

93000

Hydraulic Height

220

Drainage Area

57725

Nid Storage

19100000

Structural Height

256

Outlet Gates

Vertical Lift - 0

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

256
       
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.