Aurora wants to build system's largest reservoir in Park County

The state's water plan projects a major gap in water supply by 2050. In order to meet future water demands in growing cities like Aurora, there must be aggressive conservation, water reuse and water storage. Projects like Wild Horse Reservoir are being planned to help meet that need.

The proposed Wild Horse Reservoir would be built near Hartsel in Park County, about six miles west of Spinney Reservoir. It would used by the City of Aurora as a storage reservoir, whose existing water rights from the Arkansas and Colorado rivers will be the source of water. No new rights or decrees are being pursued for the project.

Greg Baker, Deputy Director for Internal/External Relations at Aurora Water, says maintaining sustainable water supplies through reservoir storage allows Aurora to use the water it owns when it needs it.

Wild Horse would be the largest reservoir in Aurora's system.

"We can serve three to four households with one acre-foot of water. If you multiply that by 93,000 acre-feet, you're talking about almost 400,000 households that could be served out of this," said Baker.

Water from Wild Horse would be transported from a pipeline running east to Spinney Reservoir. From there, water enters the South Platte River and pipelines to the city's water treatment facilities.

"By splitting this out, we can actually put our Arkansas, Colorado water into Wild Horse. Spinney will be for our South Platte water. It makes it much easier to manage this in wet years especially," said Baker. "We're simply taking water we already have and we're better managing it."

Two-thirds of the land needed to build the reservoir has already been acquired. Most of the property needed for construction is privately owned and undeveloped. Several small parcels are owned by the U.S. Bureau of Land Management.

According to Park County, the reservoir will bring economic benefits to the region. In addition to the financial benefits of construction, there is potential for additional recreational and commercial opportunities.

Baker says initial studies show no jurisdictional wetlands or endangered species at the site.

"That's what makes Wild Horse an excellent project for us because there are very little environmental impacts," said Baker. The reservoir would be 'off-channel', so they won't have to dam rivers or streams.

Baker adds the benefit of storing water at a higher elevation reduces evaporation, minimizes spills and reduces waste.

Gary Wockner, founder of Save the Colorado, told CBS News Colorado, "We have concerns, but we are waiting to see permit documents before we take a position. We don't yet know what impact the project would have on the Arkansas or Colorado rivers, which will trigger our level of interest."

The current cost of the project is estimated to be $600 million to $800 million. According to Aurora Water, it would be split between development (tap) fees and water rates. Baker says most of the project would be funded by development fees, which are based on projected water use, to ensure growth pays for itself.

"We're looking at a population going up 40% in the next 20 years. We need to be acquiring water. We need to be acquiring storage. We need to be looking for innovative ways in which to bring water to the community," said Baker. "If we don't have the water to meet that growth, we're going to constrain that ability to grow as a city."

Aurora Water is still in the pre-permitting phase of the project. The target completion date is late 2020s.