Jensen Reservoir Report

Last Updated: December 5, 2025

Jensen, also known as Cold Sore, is a privately owned irrigation dam located in Mesa, Colorado.


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Summary

Completed in 1913, this Earth type dam stands at 7 feet high and spans 126 feet in length, with a storage capacity of 110 acre-feet. Situated on Cottonwood Creek-OS, Jensen serves the crucial purpose of irrigation, supporting agricultural activities in the region.

Despite its age, Jensen has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. The last inspection of the dam was conducted in August 1993, with a moderate risk assessment score of 3. While it is state-regulated and undergoes regular inspections, its emergency action plan status, inundation maps, and risk management measures are currently undocumented, suggesting areas for potential improvement in terms of safety and preparedness.

Water resource and climate enthusiasts will be intrigued by Jensen's historical significance as an irrigation structure in Colorado. Its location in Molina, along with its design and operational details, provide valuable insight into the importance of dams for water management and agriculture in the region. As efforts continue to assess and manage risks associated with aging infrastructure like Jensen, there is a clear need for ongoing maintenance and monitoring to ensure the safety and reliability of this vital water resource.

Year Completed

1913

Dam Length

126

Dam Height

7

River Or Stream

COTTONWOOD CREEK-OS

Primary Dam Type

Earth

Surface Area

20

Hydraulic Height

7

Nid Storage

110

Structural Height

7

Hazard Potential

Low

Nid Height

7
       
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.