Hyrum Reservoir Reservoir Report

Last Updated: December 5, 2025

Hyrum Reservoir is located in Cache County in Utah and was constructed in 1935 as part of the Civilian Conservation Corps program.


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Summary

The reservoir has a capacity of 14,000 acre-feet and is primarily used for irrigation purposes in the Cache Valley. The hydrology of the reservoir is primarily fed by the Little Bear River, which is a tributary of the Bear River. The Little Bear River is a snowmelt-dominated stream and the reservoir receives a significant amount of its water supply from snowpack in the surrounding mountains. The reservoir is also popular for recreational activities such as fishing, boating, and camping, and is stocked with rainbow trout, bluegill, and channel catfish. Additionally, the reservoir supports several agricultural activities, including the cultivation of hay, barley, and corn.

Reservoir Details

Storage 24hr Change 1.99%
Percent of Normal 47%
Minimum 48.01 acre-ft
1994-09-24
Maximum 16,240.0 acre-ft
1986-05-31
Average 9,057 acre-ft
Nid_Height 18
Hydraulic_Height 6
Year_Completed 1935
Dam_Height 18
Hazard_Potential High
Structural_Height 18
Primary_Dam_Type Earth
River_Or_Stream LITTLE BEAR RIVER
Foundations Rock
Surface_Area 480
Nid_Storage 18685
Dam_Length 850
       
Seasonal Comparison
Storage Levels
Storage Levels
Pool Elevation Levels
Total Release Levels
Inflow Levels

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.