Clennon Reservoir Report

Last Updated: December 5, 2025

Clennon, located in Weld County, Colorado, is a privately-owned irrigation dam built in 1879 on the St.


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Summary

Vrain Creek-OS. Standing at a height of 14 feet, with a hydraulic height of 10 feet, and a length of 2000 feet, this earth dam serves the primary purpose of irrigation. With a storage capacity of 147 acre-feet, Clennon plays a significant role in managing water resources in the area.

Despite its age, Clennon is rated as being in satisfactory condition, with a significant hazard potential due to its uncontrolled spillway type. Regular inspections are conducted on this dam, with the last assessment done in November 2019. The risk assessment for Clennon is moderate, with a DSAC (Dam Safety Action Classification) of 3, indicating a need for ongoing risk management measures to ensure the safety and integrity of the structure.

Enthusiasts of water resources and climate will find Clennon to be a fascinating example of historical water infrastructure in Colorado. Its role in irrigation and water management, combined with its unique design features and risk assessment, make it a noteworthy site for those interested in the intersection of water resources and engineering.

Year Completed

1879

Dam Length

2000

Dam Height

14

River Or Stream

ST. VRAIN CREEK-OS

Primary Dam Type

Earth

Surface Area

17

Hydraulic Height

10

Nid Storage

147

Structural Height

14

Hazard Potential

Significant

Nid Height

14
       
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.