Yuma Desalting Plant Could Boost US Water Supply To Mexico During The Drought

September 20, 2013

The severe drought that hit the Southwest 14 years ago is expected to continue to bring down water levels on the Colorado River. 

plant Two large storage tanks at the Yuma Desalting Plant stand a few stories above ground. (Photo by Steve Shadley-KJZZ)

Federal and state officials said a water shortage is possible for millions of people in Arizona and other states by 2016. A rarely used desalting plant in Yuma could start sending water to Mexico in an effort to keep U.S. reservoirs full. The Yuma Desalting Plant is located along the state line between Arizona and California on the sandy banks of the Colorado River. 

One of the first things you will notice at the plant is the loud hum of the water filtering equipment. Charles McCaughey has been a mechanical engineer at the plant for nine years. He is standing at the front entrance of the building near a canal where you can see the river on the other side of a chain link fence. 

“The water flows from the canal which is on the other side of the levy right here, and that’s the Colorado River levy, and from here it's pumped from these pumps right here up to the very large vessels on the hill,"  said McCaughey. "And they hold over 4 million gallons of water, and that’s where we do our softening."

It is a 60 acre industrial landscape in the middle of the desert with miles of pipes running in all directions. Many pipes are filled with delicate plastic membranes that remove salt and other impurities from the water through reverse osmosis. 

“The problem with reverse osmosis is it’s not the low hanging fruit, it’s the more high hanging fruit. It’s expensive,” said McCaughey.

It takes a lot of electricity to run the filtration system, and that is what drives up the costs. Construction on the plant was completed 20 years ago. It had a final price tag of $250 million, and despite the big investment the plant has only operated twice since it was finished in the early 1990s, but if the plant had to operate right now, the technology would have to be updated for a cost of more than $20 million.   

Anne Castle is assistant water and science secretary with the U.S. Department of Interior. 

“It was recently tested two years ago for a year of operation and created about 30,000 acre feet of water that wouldn’t otherwise have been in the system," said Castle.

She defends the plant even though it cost taxpayers hundreds of millions of dollars and has not seen a lot of action. Castle said the U.S. is also obligated to keep the plant ready to operate under a 70-year-old water treaty with Mexico. When the river cannot fill a Mexican wetland near the Sea of Cortez, then the U.S. must send water south of the border. 

“So, we are looking at a very significant restoration of the riparian ecosystem around the Colorado River Delta,” said Castle.

She said the Yuma Desalting Plant is beneficial to water users in Arizona too. By sending the treated salt-free water to Mexico, the Bureau of Reclamation is able to store more water in Lakes Powell and Mead in northern Arizona, which are now both only half full. 

“It’s one of the arrows in our quiver in dealing with this drought situation,” Castle said.

The plant is one option. She said stepped up conservation efforts and additional water storage also may go into effect if the area does not receive a lot of rain and snow soon. Elston Grubaugh is general manager of the Wellton-Mohawk Irrigation District near Yuma.

“We are all concerned about the drought on the Colorado River,” said Grubaugh.

The farm rich area supplies all of the groundwater that the plant uses. The water has high salt content because of the type of soil here, and salinity is a natural byproduct of irrigating lettuce and other crops harvested in this valley. Grubaugh said right now there is enough water to supplement Mexico. 

  “If that drought continues then we could be in trouble. That’s not going to be a good situation, and that’s something we hope to avoid,” Grubaugh said.

Arizona has asked the federal government to process more water at the plant. Tom Buschatzke is with the Arizona Department of Water Resources.

"There’s no silver bullet, there’s no one solution. We are going to have to cobble together a lot of small things, maybe like the Yuma Desalting Plant, along with other things to make the system more sustainable and resilient,” Buschatzke said.

He said Mexico recently agreed to accept lower water deliveries from the Colorado River if the severe drought continues, but Buschatzke said when the region receives a lot of rain and snow, Mexico will be allowed to take more water from the U.S. whether it comes from the desalting plant or not.