Casey Kuhn/KJZZ

Canals bring water from the Colorado, Salt, and Verde Rivers into the Valley of the Sun.

Gilbert is one step closer to securing a new water supply for the town.

Town Council last month approved a 100-year water lease with the San Carlos Apache Tribe for 5,925 acre feet of water annually.

“Long-term water leases are valuable both for assurance for our residents that they have enough supplies in the current time as well as for the future,” said Gilbert Water Resources Manager Eric Braun.

Braun estimates the new water allotment will increase the town’s water portfolio by up to 8 percent.

An acre-foot refers to the amount of water it would take to cover an acre of land in one foot of water — about 325,851 gallons of water. That’s enough for a family of four to have water for a year.

Gilbert gets its water from a variety of sources — about one-half from the Central Arizona Project, one-third from the Salt and Verde River watershed and smaller amounts of ground and reclaimed water.

“Gilbert is required to have 100 years' water supply for any new development in hand prior to that development actually occurring,” Braun said. That’s part of Arizona’s Water Management Act.

The San Carlos Apache Tribe receives 46,525 acre-feet of water from the Central Arizona Project as part of a settlement.

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The deal was first brokered in 2010, but federal agencies delayed the lease until now. Though the tribe and the town have signed off, the lease won’t be final until the Bureau of Reclamation approves it.

Gilbert’s lease with the tribe will be subordinate to two existing water deals in times of shortage.

“In the time of shortage, Gilbert will take the brunt of those shortages,” Braun said.

Part of the lease agreement is that Gilbert cannot use the water for golf courses or mining.

‘Water for tribes is viewed a little bit differently than most other folks for tribes,” Braun said. “They view water physically, but also kind of spiritually... We respect that and we understand that.”

If the Bureau of Reclamation approves the deal before October, Gilbert will start receiving water from the San Carlos Apache allotment next year.