A desalting plant in Arizona that could help boost water supplies in the Colorado River has been restarted for the first time in 14 years. Meanwhile, water officials and environmental groups are exploring how to operate the plant while protecting a nearby wetland.

The 90-day demonstration run, which began March 1 and will end May 31, is intended to test equipment at the $211 million facility, which has been shuttered since 1993, when flooding on the Gila River damaged the plant.

"We need to see if we have problem areas," said Jack Simes, a spokesman for the Bureau of Reclamation's Yuma, Ariz., office.

The long-dormant Yuma, Ariz., desalination plant was brought back into test operations this month after a deal was reached to protect wetlands. Photo courtesy of Bureau of Reclamation.

Water officials have been interested in reopening the plant for years. Treating salty irrigation water and returning it to the Colorado River would allow the United States to meet its treaty obligations to Mexico while keeping more water in U.S. reservoirs upstream. Without the plant -- the world's largest reverse osmosis desalting facility -- the water is too saline to deliver to Mexico. With treatment, that water could be sent south, allowing water mangers to keep about 78,000 acre-feet of Colorado River water in Lake Mead per year, according to estimates by the Central Arizona Project, which distributes the state's share of Colorado River water stored in the reservoir.

But the closure of the plant, about five miles west of Yuma, resulted in an incidental ecological benefit: Highly saline agricultural water that would have been diverted for treatment to the plant has been rerouted into the Colorado River Delta, bypassing the Lower Colorado River and expanding the Cienega de Santa Clara to 40,000 acres.

The wetland has become an important stop for migratory birds and provides crucial habitat for 95 species, including the endangered Yuma clapper rail.

Environmental groups, concerned about the loss of the wetland, had fought the reopening of the plant. Bringing the plant back online would mean that instead of the irrigation runoff it receives now, the wetland would receive only a stream of brine waste from the desalting plant, they claimed.

Impasse resolved

In more recent years, there has been something of a breakthrough in the impasse, with environmentalists working with water officials to figure out how to operate the plant while protecting the wetland. Two years ago, the Yuma Desalting Plant/Cienega de Santa Clara Workgroup presented the Bureau of Reclamation with a set of recommendations that included paying farmers to fallow their fields to provide an alternate source of water for the wetland and improving water conservation on agricultural lands (Land Letter, May 5, 2005).

While the demonstration run is designed to test plant equipment, environmentalists say they support the test and that it is unlikely that the demonstration would have happened without the efforts of the work group.

"Although Reclamation has not committed to following any of those recommendations if they want to operate the plant in the future, I'm optimistic that possible solutions have been defined," said Jennifer Pitt, a senior policy analyst with Environmental Defense. "And because we've shown a way to operate the plant without harming the wetlands, it's unlikely that the wetlands will be compromised."

While Reclamation has not adopted the work group's recommendations, last year the agency negotiated a forbearance agreement with irrigators that allows the use of their water for a fee of $170 per acre-foot.

Simes said that during the test run, the Central Arizona Project and the University or Arizona will study the wetland. While the demonstration run, which will be at 10 percent of capacity, is likely to be too small to determine potential effects on the wetland from a fully operating plant, the study is an important step for learning more about the wetland, said Pat Graham, state director for the Nature Conservancy.