Wasson Reservoir Report

Last Updated: December 5, 2025

Wasson, also known as Mountain Supply #22, is a privately owned dam located in Larimer County, Colorado, near the city of Wellington.


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Summary

Completed in 1965, this earth-type dam stands at a height of 23 feet and has a maximum storage capacity of 371 acre-feet. Its primary purpose is irrigation, serving the Cache La Poudre River-TR watershed with a normal storage capacity of 231 acre-feet.

The dam has a low hazard potential and is in satisfactory condition, as of the last inspection in August 2019. It has an uncontrolled spillway with a width of 25 feet and a maximum discharge rate of 526 cubic feet per second. While it is regulated and inspected by the Colorado Division of Water Resources, Wasson does not have a designated Emergency Action Plan in place. The risk assessment for the dam is moderate, with a rating of 3 out of 5.

Located in a scenic area close to the Cache La Poudre River, Wasson serves as a vital water resource for irrigation purposes in the region. Its historical significance and operational efficiency make it a noteworthy structure for water resource and climate enthusiasts to study and appreciate in the context of Colorado's water management practices.

Year Completed

1965

Dam Length

880

Dam Height

15

River Or Stream

CACHE LA POUDRE RIVER-TR

Primary Dam Type

Earth

Surface Area

35

Hydraulic Height

15

Drainage Area

1

Nid Storage

371

Structural Height

23

Hazard Potential

Low

Nid Height

23
       
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.