By Mark Carlisle | Daily Independent (abridged)
Facing an uncertain future with its Colorado River supply, the city of Phoenix could start using backup water supplies as early as January.
There is also a possibility some mandatory water cuts could be implemented in the city as soon as the end of this year. The city plans to bolster water sources through advanced wastewater treatment and is looking at a plan to share water regionally with other Arizona cities.
City council members discussing the issue (on April 28) stressed Phoenix has been preparing for drought for decades and has contingency plans in place. They also highlighted that thanks to conservation efforts, the city uses so much less water per capita today than it did in 1990 that the city’s total water use is about the same despite the population ballooning from under a million to more than 1.6 million.
Backup water sources
With drought causing historically low levels along the Colorado River, the seven basin states that share Colorado River water failed to reach an agreement earlier this year. Now, the U.S. Bureau of Reclamation will announce a decision by this summer on how further cuts to the river’s supply will be shared among states. Those cuts will go into effect at the start of 2027.
Phoenix receives about 40% of its water supply from the Colorado River, with 58% coming from the Salt and Verde rivers and 2% coming from groundwater.
City of Phoenix Water Services staff shared with council that the city’s supply of Colorado River water currently outpaces its demand, but that would no longer be the case with as much as a 25% cut of the city’s Colorado River water. Under the most drastic forecast by the Bureau of Reclamation’s draft environmental impact statement, central Arizona could lose all of its Colorado River water.
Phoenix’s backup water supplies – renewable backups, previously stored water credits and groundwater – could cover demand in scenarios of up to a 75% cut of Phoenix’s Colorado River water supply but not a 100% cut.
Groundwater is the last backup supply the city would tap into, Water Services Director Brandy Kelso told council, because it is not a renewable supply.
Read more (subscriber content)
Some stories may only appear as partial reprints because of publisher restrictions.