California's Katrina Is Coming
Joyce Park stashed this in Silicon Valley
Live in California and feel like you just don't have enough to worry about with the drought, rising sea levels, and earthquakes? Wired is here for you with a new thing: levee breaches in the Delta! Could happen this winter with the El Niño!
Yeah, one more thing to lose sleep about:
The years-long dry spell isn’t what keeps engineers, economists, and state water planners awake at night. No, they worry about the network of levees at the crux of California’s plumbing—a massive freshwater confluence called the Sacramento-San Joaquin River Delta.
Most of the state’s water is drawn from the Delta, protected by levees that pretty much amount to mounds of dirt, even when compared to infrastructure that infamously failed New Orleans during Hurricane Katrina. Hurricanes don’t hit NorCal, but these levees are alarmingly susceptible to disaster. If enough were to breach—in an earthquake perhaps, or severe El Niño storm—sea water from San Francisco Bay could rush in, tainting the water supply serving two-thirds of the state. The worst-case scenario could cause up to three years of severely curtailed water for most Californians.
Even if you’re not a California dreamer, this affects you. Delta water keeps Hollywood in the movie business, Silicon Valley in the tech business, and 750,000 acres of farmland in the business of producing half of America’s veggies, fruits, and nuts. If the levees go, so goes the water for 25 million residents of the world’s seventh largest economy.
The Delta is a singular place, even in California’s varied geography. Most of California’s interior water flows into two river systems—the Sacramento from the north, and the San Joaquin from the south. Where they meet, just east of the San Francisco Bay, they form a muggy tidal marsh with more than 70 inhabited islands. Most of these islands sit below sea level, due to groundwater pumping and natural compaction, and are ringed by tall, earthen levees. “An island in the Delta is really a bowl surrounded by a levee,” says Dave Mraz, chief levee engineer for the state Department of Water Resources. “If that levee goes, then that bowl is filled with water.”
Since 1900, over 160 levees have breached in the Delta. Several breached islands were never reclaimed, and now exist only as levee-top lagoons.
I'm not a big fan of the patch and pray approach.
Climate change poses another risk, because it will bring higher tides and stronger storms. A 2010 paper predicted that by 2100, the storms that interrupt California’s increasingly prolonged droughts will be 110 to 150 percent stronger than today. But like Katrina in New Orleans, higher seas and worse storms only expose structural weaknesses already present in the system. “Saying climate change put the levees at risk would be like saying an iceberg killed more than 1,500 on the Titanic,” says Hamed Hamedifar, a structural engineering consultant for UC Berkeley’s Center for Catastrophic Risk Management.
The worst case scenario would happen during a drought, when freshwater pressure is lowest. Fifty breaches across many islands would flood the Delta with about 1.2 million acre-feet of Pacific Ocean water. Getting the salinity levels back to drinking quality could take years. First, engineers would have to rebuild the levees and pump out the submerged islands. Then, they’d have to wait for enough fresh water to flow through the Delta to flush out the salt. “Normally the Delta will freshen up every winter,” says Mraz, the state engineer. “But if we happen to be in a drought when the breach happens it could take a long time.”
He concedes that a close-enough, strong-enough earthquake would be utterly catastrophic. But he says the risk from stormwater flooding isn’t so bad. While a monster storm could take out numerous levees, the floods themselves would minimize the risk of a Big Gulp, as the Delta will have a surfeit of fresh water. He also points out that the Army Corps, along with state and local agencies, have invested more than $700 million on upgrades since the 1960s to buttress against storm flooding. This includes nearly $275 million from Proposition 1, which voters passed last year.
Critics, however, feel like that amount is nowhere near what’s needed to safeguard the state’s water delivery system. “The US in general has a highly reactive stance relative to risk,” says Bea. Which is his way of saying that most of that money will go to plugging leaks as they are found. “If something floods, we pump it out and patch it, then we return to our enjoyable, productive lives. In essence we’re in this reactive process of fixing the last accident.”
What’s to be done? Bea says the best solution is “strategic withdrawal”: Depopulate the Delta, and route water utilities around it. Depopulation aside, this is close to the solution the state is most actively working toward. The Delta Tunnels would pass below the fraught levees, connecting the pumps at the south end directly to the Sacramento River further upstream.
But this $25 billion fix would take nearly 10 years to build. It might solve the water supply issue, but doesn’t address all the non-water infrastructure, like the railroad tracks, shipping lanes, electrical infrastructure, or the section of state highway that runs along the top of one levee. Not to mention all the people and agriculture in the area. Its many opponents—an unlikely coalition of environmentalists and Delta farmers, who say it would give Southern Californians an even more direct line to Northern California water—have stalled the project for nearly a decade through various legal challenges.
Right now, the only solution in progress is slow, systematic levee maintenance. Or, as Bea puts it: “Patch and pray.” Mraz has a more positive outlook, saying that due to these persistent upgrades, “the levees work better today than they ever have in their life.” That’s California, always dreaming of a better tomorrow.