IRVINE : Water Treatment Plan to Be Studied

A vast pool of underground water in eastern Irvine, long undrinkable because of contamination from farming and industry, could be flowing through household taps next year if a $25-million treatment program is approved next month.

The filtered ground water could supply Irvine with up to 15% of its water, reducing its reliance on imported water.

Under a proposal to be considered next month by the Orange County Water District board of directors, the county would drill six to nine new wells near Irvine Center Drive and Sand Canyon Avenue and build a treatment facility to process up to 2.2 billion gallons of water a year. The board of the Irvine Ranch Water District, which supplies water to Irvine, will be considering an agreement to operate the facility and buy the water.

Besides reducing dependence on imported water, the project will also benefit the region by cleaning up contaminated ground water, Orange County Water District spokesman Jim Van Haun said. The ground water, which is migrating to the west and threatens to contaminate existing water supplies, contains high levels of salts, nitrates, selenium and trichloroethylene, an industrial solvent, Van Haun said.

Years of watering and fertilizing agricultural land caused the salts and nitrates to seep into the water table, Van Haun said. Selenium, a naturally occurring chemical, has been found in the water at a level considered too high for safe drinking, he added.

Trichloroethylene, an industrial solvent suspected of causing cancer, may have come from the nearby El Toro Marine Corps Air Station, Van Haun said, but the Marine Corps has said thechemical probably came from several industrial sources in the area.

The Orange County Water District built a $1.1-million treatment system last year near Irvine Center Drive and Jeffrey Road to treat the contaminated water, but the stream of trichloroethylene-tainted ground water is still spreading away from the El Toro base.

The chemical could spread to safe wells in the years to come if left untreated, Van Haun said. A 1984 study recommended that the area’s ground water be treated to prevent it from contaminating other water supplies.

If the new plan is approved, the Irvine water district will blend the treated well water with imported water and water from its wells in Santa Ana. The district now imports about half of its water.

Most of the money for the project will come from a $19.3-million low-interest state loan to the Orange County Water District, Van Haun said. Selling the water to the Irvine Ranch Water District should eventually pay for the cost of the wells and treatment system, he said.

If both water districts approve the project next month, construction could begin some time next year, Van Haun said. The site of the treatment plant has yet to be determined.