Big Sand Wash Dam Reservoir Report

Last Updated: December 5, 2025

Big Sand Wash Dam, located in Upalco, Utah, is a privately owned structure regulated by the Utah Division of Water Rights.


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Summary

Constructed in 1968, this earth dam stands at a hydraulic height of 134 feet and a structural height of 142 feet, with a storage capacity of 26,500 acre-feet for irrigation purposes. The dam spans 920 feet in length and is situated on the Big Sand Wash River, with a drainage area of 26.64 square miles.

Managed by the primary owner, the dam has a high hazard potential but is currently assessed to be in satisfactory condition. With a history of state inspection, enforcement, and permitting, the dam has not undergone significant modifications in recent years. Despite its age, the structure continues to serve its purpose efficiently, providing essential water resources for the surrounding area. The dam's location in Duchesne County and its association with CH2MHILL as the designer add to its significance in the water resource management landscape.

Overall, Big Sand Wash Dam is a key infrastructure in Utah's water management system, ensuring the reliable supply of water for irrigation in the region. With its robust construction and regular inspections, the dam stands as a testament to effective engineering and maintenance practices. As water resource and climate enthusiasts, understanding the intricacies of structures like Big Sand Wash Dam is crucial for promoting sustainable water use and conservation efforts in the face of changing climate conditions.

Year Completed

1968

Dam Length

920

River Or Stream

BIG SAND WASH

Primary Dam Type

Earth

Hydraulic Height

134

Drainage Area

26.64

Nid Storage

26500

Structural Height

142

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

142
       
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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.