One earthquake could cut off 70% of California's water supply

(NaturalNews) What do you get when you cross a record-setting drought with an earthquake? This question was recently asked on NPR, and it isn't a pleasant visual. The devastation to the precarious water supply caused by a 7.8 magnitude quake on the San Andreas Fault could sever all four aqueducts at once, cutting off more than 70 percent of the water sustaining Southern California. This is a real threat and not some doomsday prediction. This means that an estimated 18 to 22 million people are just one major earthquake away from being completely cut off from their water supply.

Pat Abbott, a professor of geology at San Diego State University, explains that much of California's water supply crosses over one of the earth's most active fault systems. This situation has many engineers scrambling to put backup plans into place in the event that this occurs. And the reality is that most of Southern California's water travels through the aqueduct system in the northern part of the state. The concern escalating is that those systems run directly over the San Andreas Fault.

Learning from the past

When we review the 1857 Fort Tejon earthquake where the land shifted a full 30 feet in 2 minutes, it isn't hard to visual the structural damage to the aqueduct system this situation would bring. Getting to the broken aqueducts and making the repairs could take a very long time, leaving most of the residents with no water for their homes or businesses.

Pre-planning costs for this scenario are expensive, and having the ability to actually carry them out is another story. Finding alternate solutions like man-made lakes, additional water storage units and additions to the San Vicente Dam are among the discussions taking place.

"It's a really concerning issue for the city of Los Angeles," said Craig Davis, an engineer with the LA Department of Water and Power, which oversees the LA aqueduct. Additionally, studies reveal that it would take a year or more to rebuild the aqueducts, with loses estimated at $53 billion. The challenge lies in the fact that you can't avoid the fault when bringing water from the north. So Davis and other engineers and water officials are searching for viable solutions before it happens.

Possible solutions

Engineers need to give this challenge a fresh perspective and redesign for long-term drought survival. Although the LA aqueduct crosses the San Andreas Fault in an underground tunnel which would shift and crumble in a big quake, complete service disruption could be avoided by installing a high-density polyethylene pipe that could survive the force, according to Davis. "You can almost collapse this pipe in its entirety and still get water through this, and there are some examples of ductile pipes in similar types of fault rupture events in Turkey that actually did this," Davis said.

LA Water and Power proposes that this type of pipe be placed in the existing tunnel to keep some water flowing should there be a major quake. It's similar to what the San Francisco Bay Area did after its 1989 earthquake. Abby Figueroa of the East Bay Municipal Utility District says engineers placed a reinforced pipe on sliding cradles inside a tunnel. "And we made it so that the pipeline could shift with the movement of the earth and that way it would minimize any damage," she said.

So you might ask, who gets to pay for this kind of solution? That project was funded by a surcharge added to local water bills, and this is what might just have to happen to fund the proposed $10 million upgrade.

Sources:

http://www.nbcsandiego.com

http://www.npr.org

http://www.mwdfacts.com