Halligan Reservoir is an existing reservoir on the North Fork of the Poudre River. The North Poudre Irrigation Company (NPIC) owns the current water stored in the reservoir and the City of Fort Collins owns the existing dam and immediate surrounding property.

The current 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 increase Halligan Reservoir’s capacity from approximately 6,400 acre-feet to roughly 14,500 acre-feet (for reference, that’s 1/10th the volume and 1/5th the area of Horsetooth Reservoir). Approximately 8,200 acre-feet of additional water will belong to the City and be used during dry years and prolonged drought to supplement Fort Collins 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 the 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. 

The City 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.

Additionally, with so many water supply projects across Colorado right now, we have the advantage of being able to use the lessons learned from other organizations who are in or recently completed permitting. We're taking into account what the surrounding communities have said and looking at how we can make this the best project to meet our community's needs. 

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