Adherents clamoring for more irrigation water for California farms have gained a powerful ally: the sun. It’s helping desalinate brackish water in one important Central California farm community.

An Israeli company has set up its desalination plant on property owned by the 44,000-acre Panoche Water and Drainage District in Firebaugh in western Fresno County. In the pilot phase the unit has cleaned and returned to the distribution system as much as 80 gallons per minute irrigation water of a purer quality than farmers can obtain from their own wells or from district canals. Instead of using conventional power sources the unit relies on solar power.

 

 

The installation is located near an area that collects drainage runoff from several large farms in the water district. It has been standard practice for years for farms in the area to install drainage tiles below ground to allow the irrigation water which both carries and collects crop-damaging salts, boron and other minerals to drain away from crop roots.

The simplest explanation of the cleansing process compares it to boiling water on the kitchen stove. The steam carries the salt and other minerals away, leaving a purified liquid. Instead of a gas or electric burner, a special vegetable oil heated by the magnified rays of the sun does the job at Panoche, utilizing a shiny 525-foot long parabolic collector that looks a little like an inverted wiener-shaped umbrella.

Once the water has been cleansed of damaging salts it is added to canal water the district receives from the San Luis Reservoir and redistributes it to its farmer members.

 

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Operation of the plant for the past year has been considered experimental, but Dennis Falaschi, manager of the water and drainage district, says his members are ready to enter a long-term commitment with manufacturer WaterFX to expand the facility. He expects the larger unit to cleanse and return to the system 300,000 acre feet of water annually.

Relying on the sun to provide the heat needed to purify the salty water puts the Panoche unit in a class separate from any of the dozen and a half desalination plants operating or planned for other California locations. Some operate by forcing brackish sea water through a membrane to which the salt clings. Power requirements for the established facilities are enormous.