Moon Lake Reservoir Report

Last Updated: December 4, 2025

Moon Lake, located in Duchesne, Utah, is a Federal-owned reservoir operated by the Bureau of Reclamation for irrigation purposes.


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Summary

Completed in 1937, this Earth dam stands at a height of 101 feet and has a storage capacity of 49,500 acre-feet. The reservoir covers a surface area of 773 acres and is fed by the Lake Fork River, with a maximum discharge capacity of 10,000 cubic feet per second.

With a high hazard potential and very high risk assessment, Moon Lake is closely monitored by the Bureau of Reclamation for safety and maintenance. The spillway, equipped with controlled gates, has a width of 48 feet to manage water flow during peak periods. Despite its age, the dam's condition assessment is currently listed as not available, highlighting the importance of regular inspections and risk management measures to ensure the safety of the surrounding area.

While Moon Lake primarily serves as an irrigation water source, it also offers recreational opportunities for visitors to enjoy its scenic beauty and outdoor activities. As a key water resource in Utah, this reservoir plays a vital role in supporting agricultural activities in the region and underscores the importance of sustainable water management practices in the face of changing climate conditions.

Year Completed

1937

Dam Length

1108

Dam Height

101

River Or Stream

LAKE FORK RIVER

Primary Dam Type

Earth

Surface Area

773

Hydraulic Height

71

Drainage Area

110

Nid Storage

49500

Structural Height

101

Hazard Potential

High

Foundations

Rock

Nid Height

101
       
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.