Thompson No 1 Reservoir Report

Last Updated: December 5, 2025

Thompson No 1, located in Mesa County, Colorado, is a privately owned earth dam constructed in 1953 for irrigation purposes.


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Summary

Standing at a height of 32 feet with a hydraulic height of 34 feet, the dam has a storage capacity of 393 acre-feet and serves the Tr-Little Dolores River watershed. With a spillway width of 100 feet and a maximum discharge of 2937 cubic feet per second, the dam's hazard potential is rated as low, making it a crucial structure for water resource management in the area.

Managed by the USDA NRCS, Thompson No 1 plays a vital role in providing water for agricultural activities in the region. Despite its moderate risk assessment, the dam's condition assessment is currently not available, emphasizing the importance of regular inspections and maintenance to ensure its long-term functionality and safety. With its strategic location in Grand Junction and close proximity to the Omaha District, Thompson No 1 stands as a key infrastructure contributing to the water security and climate resilience of the surrounding communities.

As a significant component of the local water management system, Thompson No 1 highlights the intricate interplay between human infrastructure and natural resources in sustaining agricultural livelihoods and ecosystem health in Colorado. With its historical significance dating back to the 1950s and its continued relevance in modern water management practices, this dam serves as a testament to the ongoing efforts to balance water needs, environmental protection, and climate adaptation in the face of changing conditions.

Year Completed

1953

Dam Length

1220

Dam Height

32

River Or Stream

Tr-Little Dolores River

Primary Dam Type

Earth

Hydraulic Height

34

Drainage Area

15.9

Nid Storage

393

Structural Height

34

Hazard Potential

Low

Nid Height

34
       
Seasonal Comparison

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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.