Mesa leverages tribal exchange and new reuse pipeline to mitigate Colorado River cuts

Mesa leverages tribal exchange and new reuse pipeline to mitigate Colorado River cutsWith federal operating guidelines for the Colorado River expiring, Mesa officials outlined a portfolio strategy that relies on a cost-effective exchange mechanism and the imminent commissioning of the Central Mesa Reuse Pipeline.

Mesa is preparing for potential 2027 cuts to Central Arizona Project (CAP) allocations as the Draft Environmental Impact Statement (EIS) is reviewed.

The city will activate the Central Mesa Reuse Pipeline in late February or early March 2026 to increase reclaimed water deliveries to the Gila River Indian Community.

The tribal exchange allows Mesa to procure priority water at $85 per acre-foot, significantly lower than the $365 per acre-foot rate for standard municipal CAP water.

Mesa holds 557,000 acre-feet of long-term storage credits, representing approximately 10 years of demand for its Colorado River-dependent zones.

The City of Mesa is fortifying its water supply portfolio against looming shortages on the Colorado River by expanding its partnership with the Gila River Indian Community (GRIC) and commissioning major infrastructure to support it. During a February 12, 2026, study session, retiring Water Resources Director Chris Hassert briefed the City Council on the implications of the expiring 2007 Colorado River operating guidelines. With a new Draft Environmental Impact Statement (EIS) proposing cuts to the Central Arizona Project (CAP), Mesa is focusing on the resilience of its eastern and southern service zones, which rely heavily on Colorado River water. A cornerstone of the city's strategy is a 5-to-4 water exchange agreement with the GRIC. Rooted in the 2004 Gila River Indian Community Water Rights Settlement Act, which secured the Community’s priority CAP allocation, this partnership model has operated effectively for nearly two decades. Under the arrangement, Mesa delivers reclaimed water to the community for agricultural use and receives the community's Colorado River water in return. Hassert noted that the Central Mesa Reuse Pipeline is scheduled to come online by early March 2026. This infrastructure will allow the city to increase the volume of water received through the exchange from the current 8,000 acre-feet per year to approximately 16,000 or 17,000 acre-feet. The agreement allows for a maximum exchange of up to 23,520 acre-feet annually. The exchange offers significant financial advantages. Hassert reported that the cost for the exchange water—comprised mainly of energy pumping charges—is currently $85 per acre-foot. In contrast, standard Municipal and Industrial (M&I) CAP water costs $365 per acre-foot. "By increasing how much water we get through that exchange is a big deal when it comes to reducing our budget," Hassert said. The city's organic demand in the CAP-reliant zones is approximately 58,000 acre-feet per year, exceeding its base M&I and lease allocations of roughly 53,000 acre-feet. The exchange water bridges this gap. Additionally, Mesa has access to "New Conservation Space" (NCS) water stored behind Roosevelt Dam, providing a sustainable yield of 12,500 acre-feet annually, and maintains 557,000 acre-feet of long-term storage credits—enough to cover roughly a decade of demand in the affected zones. Looking further ahead, the city is exploring a "septic to sewer" conversion program. The master plan identified approximately 3 million gallons per day currently discharged into septic fields that could be captured, treated, and added to the reuse system. This could generate an additional 3,500 acre-feet of reclaimed water annually. Assistant Director Jesse Haywood presented modeling showing that even with a hypothetical 20% cut to M&I allocations, Mesa could meet projected demand through build-out by utilizing its NCS water and groundwater allowances without immediately depleting long-term storage credits. The city has invested approximately $250 million in the Central Mesa Reuse Pipeline and expansions at the Signal Butte Water Treatment Plant to support these initiatives.