Halligan Reservoir Report

Last Updated: December 5, 2025

Halligan, also known as North Poudre #16, is a local government-owned dam located in Larimer County, Colorado.


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Summary

Completed in 1970, this arch-type structure stands at a height of 78 feet and has a hydraulic height of 78 feet. With a storage capacity of 9,312 acre-feet and a drainage area of 349 square miles, Halligan primarily serves the purpose of irrigation along the North Fork Cache La Poudre River.

Despite its fair condition assessment as of October 2020, Halligan poses a high hazard potential, which warrants regular inspections and maintenance. The dam's spillway type is uncontrolled, with a width of 110 feet, and it has a maximum discharge capacity of 10,000 cubic feet per second. Additionally, the risk assessment for Halligan is moderate, indicating a level 3 risk level that necessitates ongoing monitoring and risk management measures.

Located in Fort Collins, Halligan plays a crucial role in water resource management in the region. With its significant storage capacity and vital purpose of irrigation, the dam serves as a key infrastructure for agricultural activities and water supply. As climate change continues to impact water resources, understanding and ensuring the safety and functionality of structures like Halligan is essential for sustaining water availability and resilience in the face of changing environmental conditions.

Year Completed

1970

Dam Length

360

Dam Height

78

River Or Stream

N FORK CACHE LA POUDRE

Primary Dam Type

Arch

Surface Area

253

Hydraulic Height

78

Drainage Area

349

Nid Storage

9312

Structural Height

95

Hazard Potential

High

Nid Height

95
       
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.