Summit - Main Dam Reservoir Report

Last Updated: December 5, 2025

Summit - Main Dam, located in Dolores, Colorado, is a privately owned structure primarily used for irrigation purposes along the Lost Canyon Creek.


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Summary

Built in 1905, this earth dam stands at a height of 42 feet and stretches over 7,270 feet in length. With a maximum storage capacity of 7,050 acre-feet and a normal storage of 5,954 acre-feet, this dam plays a crucial role in water resource management in the region.

Despite being classified as a high hazard potential structure, Summit - Main Dam is currently assessed to be in fair condition as of October 2020. The dam features an uncontrolled spillway with a width of 40 feet and a slide gate for outlet control. It is subject to regular inspections, with a frequency of one inspection per year to ensure its structural integrity and safety. The risk assessment for this dam is moderate, indicating the importance of ongoing monitoring and risk management measures.

In addition to its irrigation function, Summit - Main Dam also serves as a fish and wildlife pond for recreational purposes. Situated in Montezuma County, this dam stands as a testament to early 20th-century water resource development in Colorado. As climate change impacts water availability and quality in the region, structures like Summit - Main Dam will continue to play a vital role in sustaining agriculture, wildlife, and recreational activities in the area.

Year Completed

1905

Dam Length

7270

Dam Height

42

River Or Stream

LOST CANYON CREEK-TR

Primary Dam Type

Earth

Surface Area

402

Hydraulic Height

42

Drainage Area

2

Nid Storage

7050

Structural Height

42

Outlet Gates

Slide (sluice gate) - 1

Hazard Potential

High

Nid Height

42
       
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.