Porcupine Reservoir Report

Last Updated: December 5, 2025

Porcupine is a privately owned dam located in Cache, Utah, along the East Fork Little Bear River.


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Summary

Built in 1962 for irrigation purposes, the earth dam stands at a structural height of 181 feet and has a hydraulic height of 167 feet. With a storage capacity of 15,000 acre-feet, Porcupine plays a crucial role in water management in the region, particularly for agricultural activities.

Managed by the Utah Division of Water Rights, Porcupine is subject to state regulations and inspections to ensure its safety and integrity. With a high hazard potential, regular assessments are conducted to maintain the dam's satisfactory condition. The dam's last inspection was in May 2020, with an inspection frequency of once per year. Despite the potential risks associated with the dam, emergency preparedness measures such as an Emergency Action Plan (EAP) are yet to be prepared or updated.

Located in a picturesque setting in Avon, Utah, Porcupine serves as a vital water resource for the surrounding area. As climate change continues to impact water availability and usage patterns, dams like Porcupine play a crucial role in managing and distributing water resources effectively. Understanding the importance of maintaining and regulating such infrastructure is essential for ensuring the sustainability and resilience of water systems in the face of changing climate conditions.

Year Completed

1962

Dam Length

665

River Or Stream

EAST FK LITTLE BEAR RIVER

Primary Dam Type

Earth

Hydraulic Height

167

Drainage Area

72

Nid Storage

15000

Structural Height

181

Hazard Potential

High

Nid Height

181
       
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.