Mentioned in a New York Times article.
February 27, 2008
There Will Be Floods
By ALEX PRUD’HOMME
LAST month, a 30-foot section of levee ruptured in Fernley, Nev. While the cause of the breach, which swamped 450 homes and forced dozens of people to evacuate, is unknown, anyone familiar with the drowning of New Orleans by Hurricane Katrina will tell you this: Levees fail.
Indeed, there are more than 100 antiquated earthen berms across the country in danger of collapsing. What happened in Nevada is a harbinger of a much larger problem nationwide.
In Texas City, Tex., for instance, levees protect 50,000 residents and $6 billion worth of property, including almost 5 percent of the nation’s oil-refining capacity. Imagine the consequences, in this day of $100-a-barrel oil, if those defenses fail.
Even more vulnerable are the 1,100 miles of levees in the Sacramento-San Joaquin River Delta, north of San Francisco. Cobbled together 150 years ago to provide farmland, they are now part of an intricate, fragile system that supplies fresh water to California, the eighth-largest economy in the world.
On a recent visit, I noticed that the water had risen nearly to the top of the levee on one side, while the land had subsided at least 30 feet below on the other side. The water pressure against the decrepit berm was palpable. Should the levee crack, be overtopped by a storm or liquefied by an earthquake, saltwater will surge inland, destroying lives, perhaps flooding Sacramento and paralyzing California.
A year ago the United States Army Corps of Engineers, which builds and maintains many of these levees, admitted that 122 are at risk of failure. California, with 37 at-risk levees, and Washington State, with 19, are the worst off. But the list includes levees near Albuquerque, Detroit, Hartford, Honolulu, Los Angeles, Omaha and Washington.
These levees were designed poorly and built of whatever material was close at hand — clay, soft soil, sand mixed with seashells. Tree roots, shifting stones and rodents weaken them further. The land the berms are built on often subsides, while the waters they restrain constantly probe for weak spots.