Crescent Lake #2 Reservoir Report

Last Updated: December 5, 2025

Located in Garfield County, Colorado, Crescent Lake #2, also known as Mackinaw Lake, is a privately owned earth dam constructed in 1940 primarily for irrigation purposes.


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Summary

With a height of 9 feet and a length of 305 feet, this dam has a storage capacity of 213 acre-feet and serves as a crucial water resource for the surrounding area. The dam is regulated by the Colorado Department of Water Resources, ensuring proper inspection, permitting, and enforcement to maintain its integrity.

Not only does Crescent Lake #2 provide irrigation water, but it also offers recreational opportunities for visitors to enjoy its 12-acre surface area. Despite having a low hazard potential and moderate risk assessment, the dam has not been rated for its condition as of the last inspection in July 1986. While emergency action plans and risk management measures are not currently in place, the dam's location on the South Fork Derby Creek adds to its importance in the local water resource management system.

As climate change continues to impact water resources, Crescent Lake #2 stands as a vital infrastructure for both agricultural and recreational purposes in the region. With its historical significance dating back to the mid-20th century, efforts to ensure the dam's safety and sustainability will be essential in the face of evolving environmental challenges.

Year Completed

1940

Dam Length

305

Dam Height

9

River Or Stream

S FORK DERBY CR

Primary Dam Type

Earth

Surface Area

12

Hydraulic Height

9

Drainage Area

1

Nid Storage

213

Structural Height

9

Hazard Potential

Low

Nid Height

9
       
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.