California's Katrina Moment?

As if we didn't need more reminders of the fragility of California's water supply, a disturbing report released earlier this month by the U.S. Geological Survey warned that we could be hit by mega storms that could overwhelm the state's flood protection system and leave millions of Californians without access to clean water. 

Clean water is the lifeblood of modern society.   None of the incredible scientific advances of the 20th century has affected human health as profoundly as the availability of clean water.  We drink it, we bathe in it and we use it to clean and cook our food.   Here in California, we take clean water for granted but its' continued availability could soon become a serious public health issue.

The report was based on a computer simulation conducted by a team of over 100 scientists, engineers and emergency planners.  And it underscored just how vulnerable California's fresh water system-a serpentine network of levees, flood gates, ditches, canals, dams, pumps and storm surge barriers-is to collapse from the powerful storms that could become more frequent and powerful due to global warming.

The researchers based their computer models on an extreme weather event that occurred in 1861, when a storm system that lasted forty-five days turned the Sacramento Valley into "in inland sea" and flooding was so severe that the state Capitol had to be moved from Sacramento to San Francisco.  Scientists believe storms of this magnitude-which formerly occurred once every 100 or 200 years-could become more common as the planet heats up.

Coastal cities-Los Angeles, San Francisco and San Diego-would be most vulnerable to damage from floodwaters from overflowing rivers.  Relentless downpours could also flood vast swaths of fertile farmland as far east as Stockton, completely submerging 300 miles of the Central Valley, destroying crops, killing livestock and wiping out infrastructure.    

Mega storms could also overwhelm the state's flood protection system, according to the report.  The failure of a large number of levees could cause devastating floods that could engulf more than half a million acres of farmland, and deprive residents of Los Angeles and the Bay Area of access to a major source of their water for months, or even years.

In particular, the levees that protect the Sacramento-San Joaquin Delta, a verdant estuary just south of Sacramento, are probably the most vulnerable because they are not capable of handling such a pounding. The Delta is the cornerstone of the state's fresh-water system.  That water is channeled through hundreds of miles of canals and pipelines, supplying two-thirds of the state's water, quenching the thirst of 23 million Southern Californians and irrigating farms in the San Joaquin Valley that grow much of the country's grapes, almonds, cotton, tomatoes, apricots and asparagus.

While they researchers don't think the threat is imminent, the report was meant as a warning to disaster planners.  Could floods of this magnitude truly happen here?  We need look no further than Pakistan and Australia for the answer.