Yuma desalination plant restarted for pilot run

Representatives from the US Department of the Interior and three municipal water agencies gathered on 28 April 2010 to launch a one-year pilot run of the Bureau of Reclamation’s Yuma Desalting Plant.

The Yuma plant is one of the largest brackish-water reverse-osmosis desalination plants in the USA, and was originally built to treat agricultural drainage from the Wellton-Mohawk Irrigation & Drainage District. The saline drainage water would otherwise have raised the salinity of the Colorado river to an unacceptable level as it crossed the national border into Mexico.

Though largely complete by 1991, the plant was mothballed in 1993 following damage to the canal feeding the plant, when other methods were found to keep the salinity levels in the Colorado down. Drought in the Lower Colorado basin led to reexamination of the Yuma plant in the last decade (see D&WR cover feature February/March 2007)

The Yuma pilot run actually started on 3 May 2010. The purpose of the pilot run is to operate the plant at one-third capacity for a period of one year to gather critical information about its capability to be used in the future to reliably produce water that could be used for a multitude of purposes.

Under the partnership, the Metropolitan Water District of Southern California (MWD), Central Arizona Water Conservation District (CAWCD) and Southern Nevada Water Authority (SNWA) are funding nearly US$ 14 million of the pilot run’s estimated US$ 23.2 million cost. In return, each agency will receive credit in the water stored in Lake Mead through a water conservation mechanism known as “Intentionally Created Surplus”. The amount of storage credits each agency receives will be proportionate to its funding contribution.

In total, about 21,700 acre-feet (26.8 million m³) of desalted water will be produced during the pilot run. This water will be combined with 7,300 acre-feet (9 million m³) of untreated irrigation drainage water and the total amount will be discharged into the Colorado River and included in treaty deliveries to Mexico.

The pilot run will allow retention of about 30,000 acre-feet (37 million m³) of water in Lake Mead that otherwise would have been released as part of required deliveries to Mexico.

“As the Colorado River Basin drought continues, these projects will be critical in conserving supplies for future use, while helping urban Southern California effectively manage its Colorado River deliveries,” said Angel Santiago, a vice chairman of board of directors of the MWD. “The partnership that has developed among SNWA, CAWCD and MWD, along with support from Reclamation to fund projects like these, will also be key in meeting the region’s long-term water needs.”

The ceremony also celebrated the construction of the Drop 2 Storage Reservoir Project about 30 miles west of Yuma, which is about 97% complete.