Tomahawk Dam Reservoir Report

Last Updated: December 13, 2025

Tomahawk Dam, located in Barnes County, North Dakota, is a Federal-owned structure managed by the Fish and Wildlife Service.


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Summary

Built in 1936, this earth dam stands at a height of 11 feet and spans 500 feet in length, creating a fish and wildlife pond for conservation purposes. The dam has a normal storage capacity of 369 acre-feet and a drainage area of 103.5 square miles, providing critical habitat for the local ecosystem.

Over the years, Tomahawk Dam has undergone several modifications to enhance its structural and hydraulic integrity, with the most recent upgrades in 2012. Despite being classified as having a low hazard potential, the dam's condition assessment in 2013 rated it as poor. With a moderate risk level assigned, it is crucial for ongoing risk management measures to be implemented to ensure the safety and longevity of this vital water resource infrastructure.

As enthusiasts of water resources and climate change, understanding the importance of maintaining and evaluating structures like Tomahawk Dam is essential in safeguarding our environment and wildlife habitats. With regular inspections and risk assessments, coupled with proactive management strategies, we can work towards preserving these valuable assets for future generations to come.

Years Modified

1952 - Structural, 1954 - Structural, 1979 - Hydraulic, 1979 - Structural, 2012 - Hydraulic, 2012 - Structural

Year Completed

1936

Dam Length

500

Dam Height

11

River Or Stream

Sheyenne-TR

Primary Dam Type

Earth

Surface Area

77

Hydraulic Height

11

Drainage Area

103.5

Nid Storage

761

Structural Height

11

Hazard Potential

Low

Nid Height

11
       
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.