Aurora Water selected a new proposed project site for a new reservoir, which will go in Park County to help the city plan for future growth and water needs.

The Wild Horse Reservoir project is Aurora Water’s proposal to build an off-channel reservoir near Hartsel in Park County to ensure reliable water supply into the future as Aurora grows, according to the project website.

In a year of record low snowpack, conversations about future water needs across Colorado are front and center for water officials, and Colorado as a whole anticipates needing about 400,000 acre-feet, or more than 130 billion gallons, of new water storage in the next 20 years, according to Aurora Water’s assistant general manager, Sarah Young.

An acre-foot is the amount of water needed to cover one acre of land with one foot of water.

Without a new reservoir, Aurora Water anticipates dipping into its emergency water reserves by 2045, Young said.

While Aurora Water has invested a lot in water conservation, water storage is the final tool to reliably meet water needs, Young added. Wild Horse Reservoir is intended to meet the city’s water needs reliably through 2075.

Currently, Aurora Water is in the planning and pre-permitting phase of the project. As part of the National Environmental Policy Act process, the Bureau of Land Management identified several alternative reservoir locations for review.

There are more than 20 options for reservoir locations, and officials narrowed them down to four alternatives for detailed analysis.

After reviewing the alternative locations, officials shifted the proposed project site from an original location to the Wild Horse South Reservoir site, which has advantages over the original site, Young said.

Both locations sit southwest of the existing Spinney Mountain Reservoir. The original location is a few miles south of Hartsel, between Spinney Mountain Reservoir and Antero Reservoir.

The new proposed alternative, Wild Horse South Reservoir, is another few miles south of the first location.

Putting Wild Horse Reservoir in the new proposed location would not require pumping water, Young said. It would also only require one dam instead of the three dams required for the initial project site.

“One of the riskiest parts about building a project is not only the dam embankments, but also the subsurface foundation, so it decreases construction risks substantially to only have one dam,” Young said.

Water officials chose the Park County area for its proximity to the Otero pipeline and because it sits near Aurora’s existing Colorado and Arkansas River water rights, according to Young.

The location is off-channel, meaning it would not require dams blocking existing rivers, Young said.

“In general, when people think about reservoirs, they think environmentally terrible, and I think a lot of that has to do with reservoirs that dam large rivers,” Young said. “Being off-channel, there’s not significant streamflow impacts.”

There are also no threatened or endangered species on the entire site, Young added.

At high elevation in Park County, the reservoir would lose less water to evaporation than if it sat lower, she added.

Park County residents would benefit from the project as well, Young said. The new reservoir would add recreational opportunities to the area, create new jobs and job training, provide short- and long-term economic benefits from construction, recreation and tourism, and create a new wildlife habitat to complement existing grasslands, she said.

Aurora Water officials will share updates with the Park County community in two upcoming meetings. The first is a virtual presentation on Feb. 25 at 7 p.m. Those interested in tuning in can register on the project website.

The second event is a “lunch and learn” in-person on Feb. 27 from 12 p.m. to 2 p.m. at the Hartsel Fire Station, 131 Elm St.

The permitting process is underway, and Aurora Water officials don’t know how long that process will take. Once permitting is complete, it would take about five years to build the reservoir, and several years to fill it, Young said. The total project cost will be more than $1 billion, she said.

“Making sure we have a thorough and robust permitting process is important and we would be very happy to have the storage available as soon as we can, especially when we are in a situation with the snow pack like we are this year,” Young said.

More information about the project is available on the Wild Horse Reservoir website.