Earthquake could imperil L.A.'s water supply

Los Angeles gets 88% of its water from three major aqueducts, flowing from the Colorado River, Owens Valley and the Sacramento-San Joaquin River Delta.

But as they make their way into the region, the aqueducts cross the San Andreas fault a total of 32 times.

Officials have long warned that a massive temblor on the San Andreas could destroy key sections of the aqueducts, cutting off the water supply for more than 22 million people in Southern California.

L.A. officials are for the first time taking concrete steps to address the problem. Making L.A.'s water supply less vulnerable in a huge quake will probably cost billions, and it remains unclear where that money would come from.

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Mayor Eric Garcetti has asked for proposals aimed at better protecting the water supply and developing alternatives in case a quake blocks the aqueducts. The ideas range from strengthening the waterways to developing an emergency supply for firefighters using ocean water and reclaimed water.

Los Angeles is behind the San Francisco Bay Area in this effort.

The East Bay Municipal Utility District has built backup tunnels, stronger pipes and new waterways to ensure water continues flowing from the Sierra Nevada even if one of its three main aqueducts is blocked. The efforts have cost more than $350 million, paid for by water customers, bonds and government grants.

The San Francisco Public Utilities Commission built a new water tunnel under San Francisco Bay and even installed a specially designed pipe that crosses the Hayward fault. The pipe is connected by accordion-like joints that allow it to flex and swing, even as a quake moves the earth in two directions. The projects are part of a $4.8-billion effort funded by a surcharge on water

Compared with other large cities, Los Angeles is critically dependent on water sources far from the city center, said U.S. Geological Survey seismologist Lucy Jones, the mayor's science advisor on earthquake safety.

"We're the first city that's really bet its life on outside water," Jones said. "We have to cross the faults. There's no way to not go over the fault."

Garcetti acknowledged that the high cost of the water projects, along with his proposals to retrofit thousands of vulnerable buildings and preserve access to the Internet after an earthquake, would have a total price tag in the billions. But failing to act now will exact an even greater toll economically after the Big One hits.

Water is "one of L.A.'s greatest earthquake vulnerabilities," Garcetti said. "If it were to take six months to get our water system back … residents and businesses would be forced to relocate for so long that they might never come back."

http://www.latimes.com/local/califor...ry.html#page=1


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