Mesa, Arizona, building water reuse pipeline in water rights deal

Facing strained water supplies and rapid population growth, the City of Mesa, Arizona, is taking action to increase its supply and maximize its use of recycled water.

Mesa, located in the eastern Phoenix metropolitan area, averages 9.29 inches of rain per year. The city recently began construction of a 10.5-mile pipeline to provide the nearby Gila River Indian Community with recycled water for agricultural use – in exchange for gaining access to a portion of the community’s Colorado River water rights. 

The exchange draws on a 15-year-old agreement Mesa made with the Gila River Indian Community, which says that for every 10 gallons of recycled water Mesa provides the Gila River Indian Community, the city has the right to eight gallons of Colorado River water the following year. 

The agreement allows the city to provide just under 30,000-acre feet of recycled water, which would return just shy of 25,000-acre feet of Colorado River water. Currently, Mesa is delivering 10,000-acre feet. The pipeline will double the amount of recycled water the Gila River Indian Community receives and allow the city to naturally grow into the remaining amount permitted under the agreement. (Pictured above from left, Chris Hassert; a map of the future pipeline; construction underway.)

The Gila River Indian Community owns acres of unused farmlands, which it leases to local farmers when agricultural-use water supplies allow.

“The more water they have available, the more land they can rent or lease and the more revenue they get,” said Chris Hassert, water resources director for the City of Mesa Water Resource Department. “They’re not giving up anything on the water side other than just letting us use some of their water rights that they weren’t using.”

The pipeline, called the Central Mesa Reuse Pipeline, is expected to be completed in 2025. 

“What this is doing is bolstering our surface water supplies for that part of Mesa that relies on the Colorado River water. The more we bolster the surface water supplies, the less we have to rely on groundwater,” Hassert said. “In the mid-1980s, Mesa relied on over 70% groundwater for our customers, and now we’re down to single digits and we want to keep that figure in single digits.”

In addition to bolstering the city’s valuable groundwater supplies, the pipeline will maximize Mesa’s use of its recycled water. Currently, some of that water flows into the Salt River.

“I would say one of the big attributes of this project is to make 100% beneficial use of our recycled water to make sure that none of our reuse water or recycled water is wasted,” Hassert said.

In the early 2000s, Arizona mandated that all metropolitan areas develop a water shortage management plan to improve resiliency. The four-stage plan provides a menu of actions cities can take to conserve water.