Water treatment plant to meet needs long into future

NORTHERN COLORADO — The water treatment plant planned for Northern Colorado intended to serve three cities and a water district will meet treatment needs long into the future, in some cases until full community buildout.

The plant, to be built by the Cobb Lake Regional Water Treatment Authority, is a joint effort of the Fort Collins-Loveland Water District and the towns of Windsor, Severance and Eaton. The partners will use it to primarily treat their shares of water coming from the Northern Integrated Supply Project, or NISP, which is a water development project led by the Northern Colorado Water Conservancy District and 15 partners in Northern Colorado. NISP will deliver 13 billion gallons of water and store it in two new reservoirs — Glade north of Fort Collins and Galeton northeast of Ault.

While NISP has received most of its permits, it is the subject of a lawsuit intended to delay or prevent its construction. The Cobb Lake group, however, decided to proceed with building a treatment facility and time its completion to match when water might be available, said Chris Pletcher, general manager of the Fort Collins-Loveland Water District and chairman of the Cobb Lake water authority board. The participants in the project are equal partners with equal votes, but costs will be allocated based upon usage.

The plant will treat 10,000 acre feet of water once built. There are 326,000 gallons in an acre foot.

The need for the treatment plant became evident even without the NISP factor in the equation.

“We treat our water at the Soldier Canyon project,” Pletcher said, which also handles some treatment for the North Weld County Water District and East Larimer County Water District, or ELCO. “That meets our needs now, but that plant won’t take us all the way there (to build out of the district). It’s limited by real estate and capacity. 

“We would have to increase pipe sizes of every pipe coming (out of Soldier Canyon) through Fort Collins if we were to treat everything at Soldier Canyon.” The Soldier Canyon plant is east of Horsetooth Reservoir. 

The Fort Collins-Loveland district is “only about 40% built out. We have room to grow — mostly on the east side of the district. There’s a tremendous amount of growth interest in that area. Having a new source (of treated water) on the east side of the district will be very helpful,” he said.

The district has 20,000 “billing account” customers and services about 65,000 people. Pletcher expects the district to serve between 130,000 and 150,000 people as the population continues to grow. 

The district also provides water to commercial customers, which use more water per billing account, but commercial use still pales in comparison to residential water use, he said. About 19,000 of the district’s 20,000 customers are residential.

“The new plant will meet our needs for 50 or 60 years,” Pletcher said. “Water supply will need to grow with us; we don’t have all the water we’ll need yet.”

Like the water district, the other partners in the treatment plant see the facility as critical to supplying the needs of future customers.

The plant will meet Windsor’s needs through its buildout. “This is the last piece of their puzzle,” Pletcher said.

Eaton town officials said that the Cobb Lake plant “has the ability to treat the town’s anticipated future water needs and fill the gap between anticipated local growth and future capacity with our current wholesaler.”

Severance officials said, “It will meet our remaining needs at full build-out.”

So with future needs unmet, the partners decided to join forces to build something that would meet all their needs.

“The logical step seemed to be to locate a plant where we have a new source of supply,” Pletcher said. They had a few criteria:

• It needed to be near the NISP pipeline, to avoid having to build additional pipelines.
• It needed to be near the network of ditches, so that the communities could tap into ditch water if needed in the future.
• It needed to be centrally located for delivery of the water.
• And it needed to be on a site that had some elevation, so that surface tanks could feed supply lines using gravity.

“Those things narrowed it to that location fairly quickly,” Pletcher said.

Contrary to some thinking, Cobb Lake itself will have no part in the operation. It just happens to be nearby. It won’t be used to store the partners’ NISP water.

Water will be brought to the site by pipeline, be treated and placed in on-site, ground-level tanks, and then fed out by lateral pipelines to the member communities for storage near where it will be consumed. 

Method of treatment has yet to be determined. A filter plant, such as Soldier Canyon, might be the most cost effective, but the partners are studying how to achieve the best quality for customers.

“We’re building for capacity — population growth or quantity — but also for quality,” Pletcher said. “The authority will consider the quality of the water from NISP and also state health department regulations, which change. 

“We want to match what we get from Soldier Canyon, so it all tastes the same,” he said.

“Treatment requirements are changing all the time. We need to address the hardness of the water, and emerging contaminants such as PFAS, and the rules haven’t been written yet for those.”

PFAS are polyfluoroalkyl substances, chemicals used to make fluoropolymer coatings and products that resist heat, oil, stains, grease, and water.

Designers also are considering how to handle pharmaceuticals in the water and reserve space for treating other emerging contaminants. Some contaminants in the past were not detectable but now are starting to show up in water. “Even rainwater can contain some,” he said. “Being at the top of the watershed is the best place to be for water quality but “things in the river from animals, and now chemicals in the air and from wildfires, have to be considered.”

The next step for the authority is design of the plant, with construction planned to begin in 2026 or 2027. Water treatment will begin in 2030 or perhaps as late as 2032, depending on availability of the NISP water.

The authority has begun to think about staffing for the plant. “We anticipate we’ll have trouble finding people,” Pletcher said. The partners are considering internship opportunities, and “investing in people to grow their careers.”

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