A final environmental report for Fort Collins' Halligan Reservoir expansion is out

A final environmental impact statement for Fort Collins' proposed Halligan Reservoir expansion is out, and now the public has about a month to weigh in on it.

The Halligan Reservoir project north of Fort Collins would expand the reservoir from 6,400 acre-feet to 14,600 acre-feet to help the city meet its projected water demands through 2065.

The reservoir stores water from the Poudre River, which makes up half of Fort Collins Utilities' water supply.

"The project will provide added space to store Utilities’ water rights, enabling a more robust, resilient, and reliable water supply for Utilities’ current and future customers," according to a news release from Fort Collins Utilities.

The project would require excavation and would discharge dredged or fill material into the North Fork of the Cache la Poudre River and adjacent wetlands, so it requires approval from the U.S. Army Corps of Engineers under the federal Clean Water Act.

Since a draft environmental impact study, or EIS, came out in 2019, the city has modified its plans to address some challenges in meeting guidelines for dam safety and construction.

Rather than raising the height of the current dam by about 25 feet, it now plans to build a replacement dam that is 26 feet higher than the current dam. It would be located about 200 feet downstream.

The existing dam, which is more than 110 years old, would be either partially or fully removed.

"This modified dam placement addresses the dam safety challenges and allows the existing dam to act as a coffer dam during construction, which would improve Fort Collins’ ability to manage water and sediment during construction while reducing the need to lower reservoir water levels during construction," a news release from the U.S. Army Corps of Engineers said.

This would increase the reservoir surface area from 253 acres to 391 acres, the corps said.

"The modified dam placement would not change how the Halligan Project is operated or the associated indirect effects on hydrology-related resources but would slightly change the construction footprint and associated direct effects on land-based resources," the news release said.

Utilities' news release touted local environmental benefits, including:

• restoring flows to the North Fork of the Cache la Poudre River

• improving aquatic habitat on the North Fork between Halligan and Milton Seaman Reservoirs

• providing improved fish passage on the North Fork and elsewhere.

"Overall, the project will provide measures that reduce, mitigate, or improve effects on wildlife, the environment, and neighboring residents," the news release said.

Gary Wockner, executive director of Save the Poudre, said his group hasn't taken a formal position on the project, but he said in an interview Wednesday that it is unneeded, and at more than $300 million, it's a waste of ratepayers' money.

"This is not only a bad water project, but it’s extremely fiscally irresponsible," Wockner said. "It’s the single largest capital project that the city would ever engage in, and it’s not even needed.'

He said the EIS evaluated a "no-action alternative" that can get the city about 90% of the way toward meeting its needs.

That alternative involves adjusting operations at Joe Wright Reservoir, acquiring additional North Poudre Irrigation Co. shares that come with a storage component and instituting more frequent drought restrictions.

Wockner said the city could do a lot more good with a water conservation program. For example, he suggested investing more money in a cash for grass program that gives people money to replace their lawns with low-water landscaping.

These programs are wildly popular in places like Las Vegas and Los Angeles, could save hundreds of thousands of acre-feet of water and cost probably one-tenth as much as the Halligan project, he said.

The EIS, however, says the no-action alternative doesn't meet the city's purpose and need: Even with water restrictions, the city would still be 600 acre-feet short of storage in a 1-in-50-year drought. That storage is crucial in case of an emergency, such as failure of a raw water line or intake at Horsetooth Reservoir, the EIS stated.

Comments on the final EIS will be accepted through Nov. 22. Find the report at www.nwo.usace.army.mil/Missions/Regulatory-Program/Colorado/EIS-Halligan/. You can submit comments in writing to: Cody Wheeler, Halligan Project EIS Project Manager, at NWO.HalliganEIS@usace.army.mil.

A record of decision by the U.S. Army Corps of Engineers can't happen until the city submits an application for water quality certification under the Clean Water Act and it is evaluated by the Colorado Department of Health and Environment.

In a May work session, when City Council got an update about the city's water supply, Utilities Director of Water Jason Graham said the city has sufficient water rights but one of the lowest capacities for water storage along the Front Range.

The Halligan project will likely get the city to where it needs to be to support anticipated population growth, Graham said.

But with concerns growing about the reliability of receiving water from the Colorado River — which feeds into Horsetooth Reservoir and accounts for about 50% of the city's water supply — staff asked council if they were comfortable with staff negotiating with Northern Water about potentially storing some of the city's water in its planned Glade Reservoir. Council was split on the idea.

More: Here's where Fort Collins stands on water storage and supply

About the Halligan Reservoir project

• Construction could start in 2026. The permitting process has been ongoing since 2006.

• It is located about 25 miles northwest of Fort Collins on the North Fork of the Cache la Poudre River.

• It's projected to cost $308 million.

• This project is not subject the city's new 1041 regulations, but it will have to go through Larimer County's 1041 permit process, which the county adopted in 2008.

• Halligan Reservoir's expansion would add 8,200 acre-feet of water storage for Fort Collins Utilities and would be filled with water from the Poudre River.

• Find a project overview on the city's website: fcgov.com/halligan/.

Coloradoan reporter Sady Swanson contributed to this report.

This article originally appeared on Fort Collins Coloradoan: Final EIS for Fort Collins' Halligan Reservoir expansion is out