Expanding Halligan Reservoir will help provide a reliable water supply for current and future generations of City of Fort Collins’ water customers who are vulnerable to reductions in water availability and delivery, due to prolonged drought and emergencies, such as fires, floods, landslides and infrastructure failures, as well as uncertainties around climate change.

The Halligan Water Supply Project will enhance flows on the North Fork of the Poudre River downstream of the Halligan Dam, leading to fishery and habitat improvements and restoration. The City of Fort Collins has committed to improved reservoir operations that will provide and maintain minimum flows to the North Fork year-round. Currently, the river often runs dry, which stresses fish and other wildlife habitats.

Alternative storage options require added pipes, pumping and treatment, creating increased greenhouse gas emissions and ultimately do not align with the City of Fort Collins' sustainability goals. The Halligan Reservoir expansion will inundate approximately 138 additional acres of land and about 391 acres when complete. After enlargement, Halligan Reservoir will be one-tenth the volume of Horsetooth Reservoir and one-fifth the area.

The project is the most cost-effective option to meet Fort Collins Utilities' water storage and supply needs.

The final Environmental Impact Statement (EIS) provides a comparison of costs for all the water storage alternatives considered and was released in October 2023.

The latest cost estimate for the project is $308 million, assuming construction is finished by 2027. This equates to about $37,500 per acre-foot of storage, which is significantly less than equivalent costs for other regional projects and alternatives for the City.