Hyrum Dike Reservoir Report

Last Updated: December 5, 2025

Hyrum Dike, located in Cache County, Utah, along the Little Bear River, is a federal-owned structure managed by the Bureau of Reclamation.


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Summary

Completed in 1935, this earth dam stands at 18 feet high and serves primarily for irrigation purposes, with a storage capacity of 18,685 acre-feet. Stretching 850 feet in length and covering a surface area of 480 acres, Hyrum Dike plays a crucial role in water supply management in the region.

Notable for its high hazard potential, Hyrum Dike lacks a spillway and is categorized as a high-risk structure. Despite its age, the condition assessment of the dam is currently not available, raising concerns about its long-term resilience. With the last inspection conducted in August 2020 and a designated inspection frequency of one year, the structure is closely monitored by the Bureau of Reclamation to ensure public safety and water resource sustainability.

As climate change poses new challenges to water resource management, the importance of structures like Hyrum Dike in regulating water flow and providing essential irrigation services cannot be overstated. With ongoing risk assessments and emergency action planning, efforts are being made to mitigate potential hazards and safeguard the surrounding communities. Hyrum Dike stands as a testament to the intricate balance between human infrastructure and natural resources, highlighting the critical role of water management in the face of a changing climate.

Year Completed

1935

Dam Length

850

Dam Height

18

River Or Stream

LITTLE BEAR RIVER

Primary Dam Type

Earth

Surface Area

480

Hydraulic Height

6

Nid Storage

18685

Structural Height

18

Hazard Potential

High

Foundations

Rock

Nid Height

18
       
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.