You asked: Where will Avimor get its water from?

By Margaret Carmel; BoiseDev

The entrance of Avimor off of Highway 55. Photo: Margaret Carmel/BoiseDev

Police, fire, and emergency medical services aren’t the only essentials a developer needs to sort out when building a subdivision in the Boise foothills.

Avimor, a growing community spanning the Ada, Boise, and Gem county lines, hopes to build nearly 10,000 homes by its completion in the coming decades. Along with the necessary road improvements, businesses, a community center, and the homes themselves, developer Dan Richter also has to build a water system to serve the homes along Highway 55. Between the combination of wells, surface water rights on the property dating back over a century, and a boost from Suez, Richter says nearly the entire project will be served by water in the ground beneath the property with extra leftover.

“We do have the wells in Avimor and the water rights in Avimor to support all of our growth,” Richter told Eagle City Council in November at a special meeting about the possible economic impacts of annexation.

Where does the water come from now?

Avimor’s first batch of homes earned approval from Ada County in 2007.

Since then, 659 homes have been constructed, and another 59 are under construction. By the time that phase is complete, 839 homes will go up on what used to be foothills ranch land. Boise County approved another 1,700 homes on its side of the line last year. Construction on that phase has not begun yet due to the impending question of whether or not the City of Eagle will choose to annex the community into city limits and gain land-use control over the project or leave it to Ada County.

Richter expects to apply with Eagle soon.

The original plan was to serve this first crop of homes with well water, but exploratory drilling found high arsenic levels in the Sandy Hill Aquifer not suitable for drinking. Richter said the aquifer in this area sits in a granite bowl beneath the surface, isolating the naturally occurring arsenic from other water sources.

To solve the problem, the Idaho Public Utilities Commission allowed water company Suez to pipe water up from the Treasure Valley and serve the 839 homes from its system. The commission required Avimor to pay the cost of building the water main up to the development. In addition to the Suez pipes, Avimor has surface water rights from two creeks on the property and the ranch homestead, which it uses to irrigate open spaces.

What’s next?

Richter hopes for the project to use groundwater in all of its remaining phases.

So far, Avimor has obtained water rights from the Idaho Department of Water Resources to pump 5 cubic feet per second, or a maximum of 3.2 million gallons per day, out of wells to serve its property. Richter said Avimor purchased an application for another five CFS from a third party, but that has not yet been approved. He said this could be filed once Avimor uses all of the first water right and has demonstrated its need for the second one. He estimates the entire 9,700 home project only needs six CFS total. Under an agreement with IDWR and the City of Eagle, these water rights will go to the city if the land is annexed.

A big reason why Richter said Avimor doesn’t need much water for its homes is due to the construction of the project. Houses are limited in how much grass they can have. The rest of the landscaping is xeriscaped with low-water usage drip irrigation, and each home is equipped with water-efficient appliances and water heaters.

“I came from 26 years in Arizona where you learned to conserve water because it was much, much more expensive,” Richter told BoiseDev in an interview. “If you wanted to irrigate your grass, it was an extra $200 or $300 a month. We’ve brought that kind of thoughtfulness about water conservation to this project.”

Avimor also has a water recycling permit from the Idaho Department of Environmental Quality. This allows the community to treat the effluent from its wastewater treatment plant and reuse it for irrigation in its parks, conserving the amount of water it needs to pump up from the aquifer. Richter also hopes to set up a system where this recycled water can get additional treatment, pumped down into the Sandy Hill Aquifer, stored there over the winter, and reused later for irrigation once the season turns. But, this aquifer storage and recovery system have not been approved yet by DEQ or IDWR.

Richter said that Avimor would need to show that the aquifer level is rising to earn approval to pump the water back out. He expects to get a permit for the reuse sometime this year, but the application is still pending.

Enter: The City of Eagle

The rules for how Avimor can use its water change a little bit if the development is annexed into the City of Eagle.

Under Eagle City code, if Avimor is annexed into city limits, it will be required to turn over its wells, pipes, and other water infrastructure system elements to the city to connect to its municipal water system. This includes Avimor’s water rights, which could be up to 10 CFS if the second water right application is approved.

Special kinds of water rights are available to municipal governments, particularly cities, allowing water to be used for more purposes and in more flexible locations due to expected growth and change over time. By giving the rights over to the City of Eagle, they can be changed so water pumped from wells at Avimor can be used anywhere within the city’s service area. This also works in reverse, meaning any water from the city can be pumped up to source Avimor.

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