Arizona mulls piping in water from Mexico as Colorado River continues decline

Arizona’s top water authority is mulling a plan to pump water from a desalination plant by the Sea of Cortez, in a bid to lessen the state’s reliance on the Colorado River.

The plan, pitched by Israeli water treatment company IDE Technologies, would involve a binational effort led by Arizona and the Mexican state of Sonora to build the desalination plant and canals to pump water into Arizona and two Sonoran cities.

Arizona’s Water Infrastructure Finance Authority this week resolved to move ahead with the nascent plan, which still has to clear regulatory hurdles at the state, local and federal levels in both Mexico and the United States.

If constructed, the desalination plant would be placed on the Sea of Cortez coast near Puerto Peñasco, a resort town on the Sonoran panhandle that’s long attracted Arizonan tourism.

The main canal from the plant would shoot north through Organ Pipe Cactus National Monument toward Arizona’s main population center surrounding Phoenix, according to a report by AZ Central.

A secondary route would pump water south from the plant to Hermosillo, Sonora’s capital, and a third canal or pipeline stemming from the main line would send water to the border city of Nogales, Sonora.

The plan would supply up to 1 million acre feet of water for purchase to Arizona, according to the IDE pitch. One acre foot is roughly the amount of water necessary to provide water to two households for one year.

Arizona’s fast-growing population has contributed to water shortages in the Southwest, as the overtaxed Colorado River struggles to supply its seven basin states and Mexico.

The Colorado River stopped reaching the ocean regularly in the 1960s, after completion of the Glen Canyon Dam. In the spring of 2014, U.S. and Mexican authorities released a “pulse flow” of water due to earthquake damage to a Mexican irrigation system, allowing the river to reach its natural destination for a few weeks.

But climate change and population growth have increased pressure on the river, forcing Southwestern states to look for other sources of water.

Still, the desalination project could face tough regulatory hurdles, in part because of its environmental impact.

Building through the Organ Pipe National Monument is one challenge, as is the issue of disposing of the concentrated brine that’s a natural byproduct of desalination. 

And according to the AZ Central report, the project could face political headwinds, as it competes with other conservation and infrastructure projects for a $1.4 billion tranche set aside for the water crisis by outgoing Gov. Doug Ducey.

While Arizona’s water options are limited, political opposition to a desalination project could also be flamed by the high relative cost of desalinated seawater.