Anderson #1 Reservoir Report

Last Updated: December 5, 2025

Anderson #1 is a significant earth dam located on Kannah Creek in Mesa County, Colorado.


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Summary

Completed in 1963, this dam serves as a crucial water supply structure for the city of Grand Junction. With a height of 26 feet and a storage capacity of 821 acre-feet, Anderson #1 plays a key role in regulating the flow of water in the region.

Maintained and regulated by the Colorado Division of Water Resources, Anderson #1 has been assessed to be in fair condition as of August 2019. Despite its significant hazard potential, the dam has been deemed to meet safety guidelines, with emergency action plans in place. The dam's inspection frequency is set at every two years, ensuring ongoing monitoring and maintenance to mitigate risks and ensure the safety of the surrounding community.

With a high risk assessment rating, Anderson #1 is a critical piece of infrastructure for water management in the area. Its location on Kannah Creek and its role in supplying water to Grand Junction highlight the importance of ongoing monitoring and maintenance to safeguard against potential hazards and ensure the continued reliable operation of this essential water resource structure.

Year Completed

1963

Dam Length

970

Dam Height

26

River Or Stream

KANNAH CREEK

Primary Dam Type

Earth

Surface Area

59

Hydraulic Height

28

Drainage Area

1

Nid Storage

821

Structural Height

29

Outlet Gates

Slide (sluice gate), Uncontrolled

Hazard Potential

Significant

Foundations

Soil

Nid Height

29
       
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.