Mountain Supply # 9 Reservoir Report

Last Updated: December 5, 2025

Mountain Supply # 9, located in Larimer, Colorado, is a privately owned irrigation dam completed in 1907 on the N.


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Summary

Fork Cache La Poudre River. This Earth dam stands at a height of 24 feet and has a maximum storage capacity of 413 acre-feet on its 57-acre surface area. With a low hazard potential and a satisfactory condition assessment as of August 2020, this dam plays a crucial role in water resource management in the region.

Managed by the Colorado Department of Water Resources, Mountain Supply # 9 serves the primary purpose of irrigation, supporting agricultural activities in the area. With a spillway width of 200 feet and a maximum discharge capacity of 14,200 cubic feet per second, this dam ensures controlled water release during peak flow events. Despite its age, regular inspections are conducted, with the last one taking place in August 2020, ensuring its continued safe operation for the community.

Located just 6 miles from Fort Collins, Mountain Supply # 9 is not only a vital water supply structure but also a part of the rich history of water resource management in Colorado. With a moderate risk assessment rating, this dam highlights the importance of ongoing monitoring and maintenance practices to ensure its long-term functionality and safety for both the environment and the surrounding community.

Year Completed

1907

Dam Length

400

Dam Height

24

River Or Stream

N. FORK CACHE LA POUDRE

Primary Dam Type

Earth

Surface Area

57

Hydraulic Height

24

Nid Storage

413

Structural Height

24

Hazard Potential

Low

Foundations

Soil

Nid Height

24
       
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.