The Halligan Water Supply Project will enlarge the existing Halligan Reservoir, providing Fort Collins Utilities with approximately 8,200 acre-feet of additional water storage. The project will provide water to current and future Utilities water customers. It will also provide increased reliability and resiliency to help protect against reductions in water availability and delivery caused by prolonged drought and emergencies. 

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An acre-foot of water is the volume of water that would fill an acre of land to a depth of one foot. This unit of measurement originated with farming practices long ago. It equals about 326,000 gallons, or enough to meet the annual water needs of three to four single-family urban households.

Halligan Reservoir is located on the North Fork of the Cache la Poudre River about 25 miles northwest of Fort Collins, near Livermore, in the foothills above Cherokee Park.

Yes. Fort Collins Utilities’ current water supplies and storage are not enough to meet the needs that come with projected growth within the Utilities service area, particularly in times of prolonged drought and emergencies. There are also uncertainties and vulnerabilities associated with climate change that will adversely impact water supplies.

Utilities uses water from Horsetooth Reservoir and the Poudre River. Utilities already owns the rights to water on the Poudre River that it currently cannot store or efficiently use. Enlarging Halligan Reservoir will allow Utilities to store this water, provide additional flows to the North Fork of the Poudre River (restoring the often-disconnected habitat), and provide increased and needed flexibility and reliability to our water supplies. Careful planning and analysis have determined that enlarging Halligan Reservoir is the most cost-effective and environmentally friendly solution to providing for these needs.

The proposed size of the Halligan Reservoir enlargement was determined through detailed modeling using a 50-year planning horizon. The goal was to have the enlargement be big enough to meet Fort Collins Utilities’ anticipated needs through 2065, without creating a larger-than-necessary reservoir, resulting in additional environmental impacts.

Without additional water storage, Fort Collins Utilities would eventually not have enough water supplies and storage for future customers. Without the Halligan Project, Utilities would need to find another storage project and/or ways to meet future water needs that would likely be much more expensive and not provide the environmental benefits to the North Fork that the Halligan Water Supply Project will. 

Without additional water storage, existing residents and businesses in Utilities’ service area would have access to less water during prolonged drought and emergencies. This is because our region's semi-arid climate means the amount of water available from month to month and year to year varies, especially during dry years and drought. Storage allows Utilities to retime water supplies from times of surplus to times of need.

Many alternatives to the Halligan Reservoir enlargement have been evaluated over the last decades and are detailed in the final Environmental Impact Statement that the U.S. Army Corps of Engineers prepared. They include: 

• Enlargement of the proposed Glade Reservoir
• Acquiring other existing agricultural reservoirs near Wellington
• Expansion and/or development of new gravel pit reservoirs along the Poudre River
• No-action

The alternatives studied to date are likely to provide a less certain water supply, raise various legal issues, and be more expensive and/or less sustainable. 

The U.S. Army Corps of Engineers will select one alternative to issue a permit, which may or may not be the Halligan Reservoir enlargement.

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• Fort Collins Utilities’ water customers will benefit from having a larger and more reliable water supply. 
• The North Poudre Irrigation Company will benefit by having the 114+ year old Halligan Dam replaced. 
• The North Fork of the Poudre River, including the fish and wildlife that live there, will benefit from additional year-round water flow in the river, as will landowners along the river, such as The Nature Conservancy.
• The region will benefit from having more secure water supplies.

Currently, Halligan Reservoir is 253 acres (surface area) and 6,400 acre-feet (volume). The expanded Halligan Reservoir will be about 391 acres and approximately 14,600 acre-feet at full capacity. For comparison, the water from Horsetooth Reservoir could fill up to 10 enlarged Halligan Reservoirs.

Water supply projects in the United States can take decades from the beginning of permitting to the end of construction. Fort Collins Utilities began the permitting process in 2006, and the reservoir cannot be enlarged until all permits are obtained. The key permit will be issued by the U.S. Army Corps of Engineers (Corps), though there are other federal, state, and local agencies that also issue important permits. The length of time needed to obtain all permits is uncertain and driven by the permitting agencies.

Once the Corps has issued its permit, the schedule for design and construction of the project will be more certain. Final design and construction will take several years.

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After the Halligan Water Supply Project is complete, Fort Collins Utilities will operate the dam and have full control of the water that is kept in the enlarged portion of the reservoir (about 8,200 acre-feet). The North Poudre Irrigation Company will continue to use the existing portion of the reservoir (about 6,400 acre-feet) for irrigation in Northern Colorado. 

Utilities will release water from the enlarged portion of Halligan Reservoir to the North Fork of the Poudre River just below the dam. Some releases will be made to improve stream flows year-round in the North Fork, though Utilities will generally keep its portion of the enlarged reservoir mostly full unless Utilities needs to use the water. 

Utilities’ Halligan Reservoir water will flow about 24 miles downstream to the confluence with the mainstem of Poudre River in Gateway Natural Area. Utilities pulls water from the main stem of Poudre River about a quarter-mile upstream of the confluence. This means the water from Halligan Reservoir cannot be physically diverted into the pipeline and sent to Utilities’ water treatment plant. Instead of building new infrastructure, Utilities will divert water at the intake pipeline and release the same amount from Halligan Reservoir. In water law, this is often called an “exchange”.

The Halligan Water Supply Project and the Northern Integrated Supply Project (NISP) are two separate projects. The Halligan Project is proposed by the City of Fort Collins (through Fort Collins Utilities) and includes expanding an existing reservoir near Livermore on the North Fork of the Poudre River. NISP is sponsored by Northern Water on behalf of 15 northern Front Range water providers, some of which surround Utilities' water service area, including the Fort Collins-Loveland Water District, which provides treated water to portions of south Fort Collins. NISP includes Glade Reservoir, which can be confused with Halligan Reservoir because it is also located northwest of Fort Collins. NISP is approximately 20 times larger than the Halligan Project.

Other regional projects include the Moffat Collection System Project (Gross Reservoir Expansion Project) and the Windy Gap Project (Chimney Hollow Reservoir).

The Halligan Water Supply Project will benefit both current and future customers and the cost of the project will be paid through a mix of funding sources including development fees, excess water use surcharges, and water rates. Fort Collins Utilities is also pursuing other funding opportunities such as grants and low-cost loans.

Based on current information, the total project costs are estimated at $308 million. The total cost includes permitting, land acquisition, mitigation, design and construction as well as contingencies to address unknown factors and risks that may need to be addressed in the future like fluctuations in labor and construction rates and aspects of design that are not yet finalized. The current cost estimate does not include the cost of future operations and maintenance, or costs related to monitoring project impacts.

The project will provide water at a cost of about $39,000 per acre-foot of firm yield. This is significantly less than equivalent costs for other regional projects and alternatives for Utilities.

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Yes. Without increased water storage, such as an enlarged Halligan Reservoir, Fort Collins Utilities would eventually not have enough water supplies and storage for future customers. Also, current and future Utilities water customers could be vulnerable to interruptions in water availability and delivery during prolonged drought or emergencies like forest fires or infrastructure failures.

The cost of water continues to rise in Northern Colorado, but the Halligan Water Supply Project remains the most cost-effective alternative to meet the future demand of Utilities water customers and provide increased reliability. Other water supplies and water storage projects in Colorado cost more when compared on a unit-cost basis. Utilities regularly evaluates the cost at milestones to determine the most cost-effective solution for our needs.

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The City of Fort Collins has a strong stewardship ethic that provides the foundation for the management of its current and future water use.

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.

All environmental impacts associated with the project, positive and negative, are thoroughly evaluated as part of the federal permitting process. Impacts are further evaluated through the state and county permitting processes. Appropriate avoidance and mitigation of negative impacts will be required. The environmental impacts are disclosed in the final Environmental Impact Statement (EIS).

The Halligan Project is smaller in scale and will make every effort to minimize environmental impacts, primarily through enlargement of an existing reservoir rather than constructing a new one.

Additionally, Fort Collins Utilities has 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 flows planned after the reservoir expansion will reconnect habitat that is currently segmented downstream of the reservoir.

Most of the negative environmental impacts will occur along the existing Halligan Reservoir shoreline and upstream of the reservoir along a ¾-mile stretch of the North Fork of the Poudre River. These areas will be newly inundated from the reservoir expansion. Other negative impacts will be temporary and related to construction.

Each impact has been thoroughly evaluated and included in the final EIS. In 2023, the Colorado Parks and Wildlife Commission and the Colorado Water Conservation Board approved the Fish and Wildlife Mitigation and Enhancement Plan. It requires impacts to be mitigated in a way that is ecologically reasonable and maintains a balance between the development of our water resources and the protection of fish and wildlife.

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Fort Collins Utilities has developed ways to mitigate impacts from enlarging Halligan Reservoir, as well as enhance the current conditions in the area around the reservoir. Utilities presents these plans in the Fish and Wildlife Mitigation and Enhancement Plan (FWMEP) and the Conceptual Mitigation Plan.

Some example measures that are included in the FWMEP and Conceptual Mitigation Plan are:

• North Fork Habitat Improvement
• Inundated Wetlands and Riparian Resources 
• Fish Habitat Improvement
• Cultural and Paleontological Resources 
• Wildlife and Special Status Species 
• Water Quality
• Air Quality
• Other Construction Impacts

Fort Collins Utilities has a comprehensive strategy to meet our current and future customers’ needs. Expanding Halligan Reservoir is one important tool in that strategy. Other tools include water efficiency and conservation efforts. To meet the challenges of a warmer and more populous future, we need to pursue solutions that include storage and water conservation.

​Water conservation is an important tool and Fort Collins Utilities has a robust program. Utilities remains committed to pursuing and developing water conservation strategies. However, as we have learned through detailed analyses, like our Water Supply Vulnerability Study, water conservation will simply not sufficiently stretch Utilities’ water supplies enough to meet the needs associated with projected growth within the Utilities service area through 2065.

Water Conservation alone will also not provide for increased reliability in Utilities water supplies for emergencies and drought. Nor will conservation alone adequately address the uncertainties and vulnerabilities associated with climate change that will adversely impact water supplies.

Learn more about the City of Fort Collins’ conservation efforts and what you can do to help.

Halligan Reservoir cannot be expanded until all permits are obtained. The key permit is a Section 404 permit under the federal Clean Water Act (404 Permit). The ultimate decision on this permit is the responsibility of the U.S. Army Corps of Engineers (Corps). The issuance of the permit is the final step in the federal National Environmental Policy Act permitting process.

The Corps has worked with other federal, state, and local agencies to evaluate multiple water storage alternatives and the impacts of each alternative on the environment and community. This data is collected and compiled in the final Environmental Impact Statement (EIS). Based on results from this permitting process, the Corps will select which water storage alternative to issue a permit.

The final EIS is part of that evaluation process. In 2025, the final EIS will be supplemented with a water quality certification. Shortly thereafter, the Corps is expected to issue a 404 Permit to conclude the federal permitting process. Once all permits and approvals are in place, and the dam design is complete, construction can begin.

In addition, the project requires permits from other government entities like the State of Colorado and Larimer County.

Many different agencies are involved, and their level of involvement depends on how they are related to the project. Some agencies are landowners around the project, such as the Bureau of Land Management and Colorado Parks and Wildlife. Others require a separate study or permit prior to construction, such as Larimer County and the Colorado Department of Health and Environment. These agencies are known as "cooperating agencies" with the U.S. Army Corps of Engineers throughout the permitting process.

Fort Collins Utilities entered the federal permitting process in 2006 and hopes to receive a final permit decision in 2026. The U.S. Army Corps of Engineers and other permitting agencies dictate the permitting schedule. Utilities has very little control over how long each process takes. Since 2000, water supply projects often require 20 years of permitting processes.

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