Thirty-six years and $150 million after it was authorized by Congress, the Yuma desalination plant cranks up Monday for a test run.
The plant will capture very salty irrigation runoff and convert it to potable water to send to Mexico to meet U.S. treaty obligations. Without it, the U.S. has to send more Colorado River water to Mexico from Lake Mead, an important but drought-plagued source of drinking water for Tucson and Phoenix.
Southwestern states have been pushing the U.S. for years to start up the long-shut desalination plant.
However, because it costs so much to run - $23 million for the 12-month test - it's still far from clear the plant will ever operate full bore.
The U.S. Bureau of Reclamation thinks it might even be cheaper and smarter to pay farmers in the Yuma area not to grow crops. The Colorado River water they now use could then go to Mexico, reducing the need for the expensive desalination.
It's the latest chapter in the long, tangled history of the Yuma Desalting Plant, whose backers call it part of the solution for the drought in the Colorado River basin.
But as a plant that has sat idle most of its 18 years and will cost four times as much to operate as the Central Arizona Project, it's also been called a white elephant.
Starting Monday, the plant will operate at 30 percent of capacity during 12 of the next 18 months.
The test will let officials clearly understand the plant's operating costs and how much additional investment they'll have to make in the plant. It will operate with a lot of aging equipment.
Arizona water officials believe that the federal government should operate the plant permanently and that the time for evaluating other alternatives is over, said Chuck Cullum, a senior policy analyst for the Central Arizona Project, which brings drinking water to Phoenix and Tucson from the river.
"We're in a drought. Let's conserve water" in Lake Mead, Cullum said. The lake is on the Arizona-Nevada border; the water is brought to Southern Arizona by the CAP canal system.
But he added, "We need to start making the difficult decisions about how we are going to move forward if the plant is not going to operate."
In what officials call unprecedented state-federal cooperation, the governments of Arizona, California and Nevada are combining to pay $14 million of the $23 million. In return, they'll get rights to a proportionate share of the water that will be stored In Lake Mead and not be released downriver to Mexico.
At full blast, the plant could produce 78,000 acre feet of water annually. That's enough to supply nearly 250,000 families for a year.
Arizona officials say the plant is needed in part because the Colorado River will run short someday.
The decade ending in 2009 was the hottest and driest decade on record in the seven-state Colorado River Basin. Runoff into the Colorado is expected to peak this spring at only 66 percent of normal flow into Lake Powell.
The plant's estimated operating cost is $484 per acre-foot, compared to about $120 an acre-foot to deliver CAP water. The plant's acre-foot cost could drop if it runs full blast because of the savings of running it on a larger scale.
Cullum acknowledged that the bureau has been very cooperative in exploring alternatives and has been caught in the middle of conflicting pressures.
Karl Flessa, a University of Arizona researcher who will work on a study monitoring the desalination plant's environmental effects, said his hunch is that officials could save the amount of water the plant would produce with conservation measures in farms and cities. Water is also needed to supply the region's few remaining wetlands, he said.
"In Western water, the focus until recently has been on increasing our supply," said Flessa, head of UA's Geosciences Department. "Now, we need to take a look at the demand side."
One problem the bureau may have in permanently running the plant is that it doesn't usually receive the kind of large budget increases that would be needed plus sizable investments to replace aging equipment, said Jennifer McCloskey, manager of the bureau's Yuma office.
A few years ago, before the economic bust started, "I would have been a little bit more optimistic" about the plant's long-term future, McCloskey said.
If authorities go the route of taking farmland out of production, however, the experience to date suggests that it won't be the whole solution.
In four years, the bureau has saved 20,000 acre-feet of water by paying $90 to $170 an acre-foot to farmers near Yuma and in Southern California.
After sending letters to all major farmers in that area, "We've gotten some takers, but not a lot … not as much as I would have anticipated at the start of the program," said Steve Hvinden, an operations director for the bureau.
Contact reporter Tony Davis at 806-7746 or firstname.lastname@example.org; follow him on Twitter at tonydavis987