The Yuma Desalting Plant is one of the largest reverse osmosis facilities in the world, and one of the least used. A new $19 billion House bill from Arizona Congressman Andy Biggs would direct the Interior Department to restore it to operational status within 180 days, putting a decades-old question back on the table: is it worth running?
What the plant was built to do
Congress authorised the plant under the Colorado River Basin Salinity Control Act of 1974, and construction was completed in 1992 for roughly $250 million, according to Bureau of Reclamation records. Its job is to treat salty drainage pumped from the Wellton-Mohawk Irrigation and Drainage District so the water can be counted toward US deliveries to Mexico under the 1944 treaty. Every acre-foot of treated water that counts toward Mexico’s share is an acre-foot that does not have to come out of Lake Mead.
A plant that has rarely run
Reclamation’s own history describes a plant that has never operated as designed. After a short early run at one-third capacity, flooding in 1993 damaged the drain that supplies its feed water. Since then it has run only in limited campaigns: a 90-day demonstration at one-tenth capacity in 2007 and a 328-day pilot at one-third capacity in 2010 and 2011. Reclamation says the plant has been maintained but largely left idle because river supplies were healthy enough that the water was not needed.
Meanwhile, since 1977 the drainage has bypassed the plant through a 53-mile canal to the Ciénega de Santa Clara in Mexico, where it created a wetland of roughly 12,000 acres. That accidental habitat is the heart of the modern dispute.
The case for and against a restart
Supporters, including Arizona Republican legislative leaders backing the Biggs bill, argue that with the Colorado River shrinking and the Lower Basin facing cuts of 1.25 million acre-feet a year, every source of new or recovered water matters. The bill would authorise $1 billion for the plant’s restoration, operation, modernisation and expansion. Our full report on the Biggs bill covers its other desalination provisions.
Critics point to cost and environmental trade-offs. KJZZ reported in March that upgrading the plant would cost tens of millions of dollars and running it many millions more, and that restarting it could disrupt the Ciénega de Santa Clara, which is now a protected area, potentially creating legal issues. Audubon has long argued that reopening the plant is too expensive and too damaging to a wetland that supports birds, including the Yuma Ridgway’s rail.
What is still unanswered
The bill’s 180-day deadline is aggressive for a facility that has sat mostly idle for more than three decades, and the coverage reviewed does not detail how the plant would be refurbished, staffed and powered on that timeline, or who would bear ongoing operating costs. The plant also treats brackish agricultural drainage rather than seawater, so it addresses a different problem from the coastal projects Arizona is studying, such as the Sea of Cortez proposal and the Rosarito plant awarded to Cox Energy in Baja California. What Yuma offers is treaty accounting: a way to deliver Mexico’s water without drawing on Lake Mead.
Sources: US Bureau of Reclamation, KJZZ, Audubon, The Gila Herald and KTAR News.