EARTHQUAKE / THE LONG ROAD BACK : Troubled Water : How the earthquake affected the Southland’s water system

What Happened:

1. The shaking and buckling caused havoc with the steel and concrete pipes and the aqueducts operated by the Los Angeles Department of Water and Power.

2. The Los Angeles Aqueduct, which brings water from the Owens Valley, broke just south of Soledad Canyon. The flow of water was quickly transferred to a second aqueduct, but engineers soon found that it too was leaking badly and shut it down.

3. A 10-foot section of the Metropolitan Water District’s major importation pipeline was severed at the Joseph Jensen Water Filtration Plant in Granada Hills. That precluded the MWD from bringing water from Northern California until early Thursday morning, when repairs were completed.

The DWP repaired damage to its second aqueduct early Thursday, but when water began to pour through, additional leaks were discovered and officials were forced to shut it down again. Repairs on both aqueducts could take up to a week to complete. The aqueducts are only part of the DWP’s problems. Of the five major trunk lines that serve the northwest San Fernando Valley area, only three are operating. Upward of 4,000 additional breaks in local mains have been reported and officials fear that as water service is restored, still more leaks in the system will be discovered. As of Friday, about 20,000 customers in some areas of the Valley, including Granada Hills and higher elevations of the Santa Monica Mountains and West Hills, were still without water.

Limited Service

Temblors can break underground sewage pipes as well as potable water mains. If water pressure drops--from high demands fighting fires or because of restricted incoming supplies--sewage can seep into the water lines.

Areas facing possible contamination include:

Limited: The northwest San Fernando Valley north of Devonshire Street and west of DeSoto Avenue, where service is slowly being restored.

Intermittent: Residents between DeSoto and Balboa Boulevard and north of the Foothill Freeway (Interstate 210) between the Golden State Freeway (Interstate 5) and Hubbard Avenue where there is currently intermittent service.

Suspect: Customers in the area west of Fairfax Avenue and south of Sunset Boulevard had been under the boil-water advisory until it was lifted Friday morning after tests showed there was no contamination. The order remained in effect for residents of the San Fernando Valley and the Santa Monica Mountains north of Sunset Boulevard--including the communities of Bel Air, Beverly Glen, Mount Olympus, Hollywood Hills and Pacific Palisades.

What Is Being Done

More than 400 DWP workers are in the San Fernando Valley fixing breaks in the water system. DWP crews are being supplemented by crews from Orange County, Long Beach, San Diego, Las Vegas and Northern California.

Work is continuing on the aqueducts, trunk lines, mains and at a series of damaged water tanks that serve higher elevations in the west Valley area. The Los Angeles Fire Department is assisting the DWP in pumping water to higher elevations in the North West Valley above Devonshire.

Some MWD water is being routed through the DWP’s pipeline network, and water from the State Water Project is now being filtered and processed by a repaired DWP plant in Sylmar.

The DWP is utilizing the seven- to 10-day supply of water it has stored in area reservoirs, and officials have begun pumping ground water from the San Fernando Valley aquifer to supplement the supply.

Most of the 20,000 residents currently without water should have service restored within a week.

How to Treat Contaminated Water

If you suspect your water is polluted, strain through paper towels or like material and boil vigorously for five minutes. This will usually make it safe from harmful bacterial contamination. Or you may purify the water by adding the chemicals shown in this table.

Amount of water: 1 quart

Amount of chlorine bleach to add to clear water: 2 drops

Amount of chlorine bleach to add to cloudy water: 4 drops

Amount of tincture of Iodine 2% to add to clear water: 3 drops

Amount of tincture of Iodine 2% to add to cloudy water: 6 drops

*

Amount of water: 1 gallon

Amount of chlorine bleach to add to clear water: 8 drops

Amount of chlorine bleach to add to cloudy water: 16 drops

Amount of tincture of Iodine 2% to add to clear water: 12 drops

Amount of tincture of Iodine 2% to add to cloudy water: 24 drops

*

Amount of water: 5 gallons

Amount of chlorine bleach to add to clear water: 1/2 teaspoon

Amount of chlorine bleach to add to cloudy water: 1 teaspoon

Amount of tincture of Iodine 2% to add to clear water: 3/4 teaspoon

Amount of tincture of Iodine 2% to add to cloudy water: 1 1/2 teaspoons

The Hidden Threat

Because of the close proximity of sewage and water lines under streets, there can be a cross-contamination after breaks caused by earthquakes. Officials are uncertain how much, if any, contamination has occurred until they can survey breaks throughout the system.

Graphics by MICHAEL HALL. Research by FREDERICK M. MUIR / Los Angeles Times