Upper Lone Tree Reservoir Report

Last Updated: December 5, 2025

Upper Lone Tree, located in Fremont County, Colorado, is a privately owned earth dam constructed in 1895 for irrigation purposes along Fourmile Creek.


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Summary

With a height of 17 feet and a length of 1190 feet, this dam has a storage capacity of 74 acre-feet, serving multiple functions including fire protection, stock water, and recreation. Despite its low hazard potential and satisfactory condition assessment, the dam poses a high risk due to its age and design, making regular inspections crucial to ensuring its safety and functionality.

Managed by the Colorado Division of Water Resources, Upper Lone Tree is subject to state regulation, permitting, and enforcement to maintain its integrity and compliance with safety standards. The dam's location in Canon City, just 2 miles from the city center, underscores its importance in providing water resources for agricultural irrigation and local community needs. With a maximum discharge capacity of 176 cubic feet per second and a surface area of 8 acres, the dam plays a vital role in water management in the region.

As a key structure in the Albuquerque District of the US Army Corps of Engineers, Upper Lone Tree stands as a testament to historic water management practices in Colorado. With a focus on sustainable water use and climate resilience, enthusiasts and stakeholders in water resources and climate change can appreciate the significance of this dam in supporting local agriculture, recreation, and environmental conservation efforts in the area.

Year Completed

1895

Dam Length

1190

Dam Height

17

River Or Stream

FOURMILE CREEK-OS

Primary Dam Type

Earth

Surface Area

8

Hydraulic Height

17

Nid Storage

74

Structural Height

17

Hazard Potential

Low

Nid Height

17
       
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.