Reclamation to conduct Yuma Desalting Plant Pilot Run

Collaborative effort with Lower Basin entities will test plants capabilities, conserve Colorado River water

Media Contact: Jennifer McCloskey , (928) 343-8123
Robert Walsh (, (702) 293-8421

For Release: November 09, 2009

Lorri Gray-Lee, Regional Director of the Bureau of Reclamation's Lower Colorado Region, today announced Reclamation's decision to conduct a pilot run of the Yuma Desalting Plant in collaboration with three water agencies from California, Nevada, and Arizona. A May 2010 start date is planned.

"Drought, population growth, and the continuing need for water in the Southwest have increased the demand on the Colorado River," said Gray-Lee. "This collaborative undertaking is one more example of the on-going State-Federal partnership effort to address the drought's impacts, conserve and stretch the river's water supply, and identify and secure additional supplies."

The Metropolitan Water District of Southern California, the Southern Nevada Water Authority, and the Central Arizona Project will provide about $14 million of the pilot run's estimated $23.2 million cost.

"It would be very difficult for Reclamation to do a pilot run of the desalting plant without the funding and other support provided by these agencies," Gray-Lee said. "That support allows Reclamation to operate the plant under the real-time conditions that are critical to obtaining the information necessary to help determine its operational readiness and long-term capabilities."

The pilot run will provide information about the plant's capability to reliably produce water that could be used for a multitude of purposes. About 21,700 acre-feet of desalted water will be produced. This water will be combined with 7,300 acre-feet of untreated irrigation drainage water and the total amount - 29,000 acre-feet - will be discharged into the Colorado River and included in Treaty deliveries to Mexico. This will reduce water releases from Lake Mead to help meet the Treaty obligations by an equal amount, conserving water in Lake Mead and augmenting the river's overall water supply.

The state agencies will receive a water storage credit of one acre-foot of water in Lake Mead for each acre-foot of water conserved by the pilot run. The amount of storage credits each agency receives will be proportionate to its funding contribution.

As a result of bi-national consultations conducted with Mexico through the International Boundary and Water Commission regarding the pilot run, the United States, Mexico and a bi-national coalition of non-governmental organizations have each committed to arrange for the conveyance of 10,000 acre-feet of water to the Cienega de Santa Clara wetlands in Mexico. The MWD, SNWA and CAP also will contribute funding for a comprehensive environmental monitoring program for the wetland that will begin prior to and conclude following the pilot run.

Construction of the YDP was authorized by the Colorado River Basin Salinity Control Act of 1974. Its purpose was to desalt irrigation drainage water flows from the Wellton-Mohawk Irrigation and Drainage District so a portion of that water could be included in Treaty-required deliveries of Colorado River water to Mexico. Since 1977, this drainage water has been conveyed from the District to the Cienega, bypassing the desalting plant.

The plant, five miles west of Yuma, Ariz., was essentially completed in 1992. Initial operational testing was conducted at about one-third capacity until early 1993, when it was stopped after flooding on the Gila River damaged a portion of the irrigation drainage canal. Since then, the plant has only operated for a three month demonstration run in 2007 at about ten percent of capacity.

Reclamation is not at this time proposing to operate the plant beyond the pilot run. "Any decision about the plant's future will be made after the pilot run is completed or terminated, and will be subject to and based upon appropriate compliance with Federal law," Gray-Lee said.

Note: An Environmental Assessment, Funding Agreement, Joint Report concerning U.S.-Mexico joint cooperative actions, and other documentation related to this action is available on Reclamation's web site at

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