Halligan Water Supply Project

Fort Collins Utilities designs its water supply system based on the City’s Water Supply and Demand Management Policy.

Over the years, careful planning has provided a water supply system that balances available water supplies with the water needs of Utilities’ water customers. However, the water we have on hand is not enough to meet the needs that come with projected growth within our service area without water restrictions, particularly in times of emergency, prolonged drought, and uncertainties associated with climate change. Without additional storage, Utilities is vulnerable to reductions in water availability and delivery.

Adequate Storage

Utilities’ water storage per customer is low compared to other Front Range water providers. Currently, Utilities owns very little storage (only 7,100 acre-feet at Joe Wright Reservoir). Existing storage facilities are not adequate to keep water supply from times of plenty for times of need (for example, from wet years into drought years). Currently, we have more water rights than we can store, so that water runs downstream unused. 

Over the last decade, Utilities has explored many storage options. Careful planning and analyses have determined that enlarging Halligan Reservoir is the most cost-effective solution that balances environmental enhancements and a secure water supply. 

City of Fort Collins Submits Water Quality Application

In June 2025, the City of Fort Collins submitted a 401 Water Quality Certification application to the Colorado Water Quality Control Division. This process is part of complying with Section 401 of the Clean Water Act and ensures the project meets water quality requirements.

Before submitting the application, the Halligan Project spent several years monitoring and documenting water quality in Halligan Reservoir and the North Fork. The Halligan Project also modeled a variety of scenarios to understand how the project might impact water quality and temperature once the new dam is operational.

The Halligan Project will meet all legal and applicable water quality requirements. Furthermore, project operations, combined with mitigation and enhancement commitments, are expected to provide additional net benefits improving pre-project baseline conditions on the North Fork.

Larimer County Commissioners Approve Permit for Halligan Project

On March 24, 2025, Larimer County’s Board of County Commissioners unanimously voted to approve a 1041 permit for the Halligan Water Supply Project.

The local 1041 permit allows Larimer County to designate conditions on the project before construction. Commissioners approved the Halligan Project permit with 53 conditions covering construction, environmental mitigation, and design review.

Final Environmental Impact Statement Released

On Oct. 23, 2023, the U.S. Army Corps of Engineers published a Notice of Availability for the Halligan Water Supply Project final Environmental Impact Statement in the Federal Register.

Fish and Wildlife Mitigation and Enhancement Plan Released

In 2023, the Colorado Parks and Wildlife Commission and the Colorado Water Conservation Board approved the Fish and Wildlife Mitigation and Enhancement Plan.

The plan follows state law, which requires impacts be mitigated in a way that is ecologically reasonable and maintains a balance between the development of our water resources and the protection of our fish and wildlife.

The City of Fort Collins has a strong stewardship ethic that provides the foundation for the management of current and future water use in the Poudre Basin. That strong ethic has been a driving force throughout the permitting process, guiding decisions around environmental mitigation and benefits. We're also taking into account what the surrounding communities have said and looking at how we can make this the best project to meet our service area needs. 

Any project of this nature has environmental impacts, but the Halligan Project has been designed to minimize impacts to the extent practicable and mitigate or enhance the environment to balance impacts and improvements. Measures are currently being incorporated to minimize the construction footprint and construction activities to reduce impacts on neighbors and wildlife during construction. The City developed a Fish and Wildlife Mitigation and Enhancement Plan that summarizes the various methods Fort Collins plans to use to minimize impacts related to the project and to mitigate impacts and enhance the existing conditions. The City has also committed to improved reservoir operations that provide minimum flows to the North Fork of the Poudre River year-round. Currently, the river often runs dry at various times throughout the year, which stresses fish and other wildlife. The minimum flows planned after the reservoir expansion will reconnect habitat that is currently segmented downstream of the reservoir.

The City is committed to finding ways to minimize project impacts and provide a net benefit to the environment. This commitment, combined with the various permitting processes required for project approval, takes many years, resulting in the lengthy permitting timeline but an overall better project.    

Our focus on stewardship has guided decisions related to the Halligan Project and has gained the project recognition as an “acceptable planned project” by Western Resource Advocates.

North Poudre Irrigation Company (NPIC) owns the water stored in Halligan Reservoir now and operates the existing dam. The City of Fort Collins owns the existing dam and immediate surrounding property.

The dam was built in 1909. This project takes advantage of the opportunity to increase water storage while addressing the needs of the aging dam. The current dam is structurally sound and safe; however, due to its age, it will need repairs in the future, with or without expanding the reservoir.    

The project will more than double Halligan Reservoir’s capacity from approximately 6,400 acre-feet to roughly 14,600 acre-feet. For reference, that’s one-tenth the volume and one-fifth the area of Horsetooth Reservoir. Halligan Reservoir's expanded capacity will provide the City about 8,200 acre-feet of additional water to be used during dry years and prolonged drought to supplement Utilities’ water supply. The City owns enough water rights to fill the enlarged portion of the reservoir without purchasing any additional rights. This water currently flows downstream unused because there is no place to capture and store it for dry years. 

The additional water supply will come from winter and spring runoff during high runoff months. Water will not be diverted for this project during the low-flow months and when water is scarce. As part of the project, the City will release minimum flows from the reservoir year-round, allowing for continual flows on the North Fork where it currently often runs dry. If expanded, the reservoir will be drawn down significantly only during prolonged drought.

Fort Collins is using a smart, multi-faceted approach to water supply through conservation and future planning. 

Water conservation is extremely important. Our customers are encouraged to use less water by creating water-wise landscapes and replacing appliances and fixtures with high-efficiency models, among other strategies. 

Our customers have risen to the challenge and have reduced per-person water use by 35% since 2000. In 2017, all of our customers used less water than in 1985. Quite an accomplishment considering Fort Collins Utilities' service area population increased by more than 50% since then. 

Even with outstanding conservation efforts, Utilities' customers are vulnerable to reductions in water availability and delivery, and conservation alone doesn’t replace the need for the Halligan Water Supply Project. 

This project will provide added protection for our customers from sudden events and emergencies that can impact our water supply at any time – prolonged drought, fires, floods, landslides and infrastructure issues (maintenance and failures), as well as uncertainty around climate change. These could compromise our water supply even with increased conservation and water restrictions. 

Water conservation helps ensure wise use of the water we have, especially during dry, hot summer months when little moisture is available naturally. In recent dry years, this conservation has allowed the City of Fort Collins to keep more water in storage for the coming years and avoid water restrictions when possible. Although conservation helps keep water in storage, our total storage capacity is limited and all the water we conserve cannot be carried over from year to year. At this time, we have more water rights than we can store, so all that water conserved by our customers passes to downstream communities.

Finally, with the Halligan Project, some water can be provided to the river for habitat improvement while water is retained for future water needs.

When the Halligan Water Supply Project is completed, it will have taken years from the official start of permitting (2006) and environmental studies through the end of construction. This doesn’t include the previous decades of pre-permitting studies that were conducted in the 1980s and 1990s.

Fort Collins Utilities last updated the cost estimate for the Halligan Project in 2022 when the 30% design was completed. The project costs, based on information known at that time, were estimated at $308 million. Current information indicates costs will change and grow as the scope is refined and permitting requirements, risks and design are better understood. 

Costs are predominantly influenced by factors outside of the City's control, including the permitting schedule and environmental mitigation requirements. Other unknown factors and risks that may need to be addressed in the future include: 

• Fluctuations in labor and construction rates
• Aspects of design that are not yet complete
• Costs of easements and other access needed for the project

The project cost does not include how much future operations and maintenance will cost. We will continue to refine project costs as permitting and design progress and project uncertainties become more clear. 

Although the cost of water continues to rise in Northern Colorado, the Halligan Project remains the most cost-effective alternative to provide a safe and reliable water supply for Utilities’ current and future customers. We evaluate the cost-effectiveness of the project at each milestone.