Forensic Engineering - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 196

The Delta's waterways and peat bogs have been regulated by eleven hundred miles of
levees, which pushed the waters back to reveal acres of rich, peaty soil that is some of
the most productive farmland in the country. An intricate system of pipes, pumps, and
aqueducts siphons freshwater from the Delta south to the Central Valley, the 4 million
residents of the Bay Area, and the 21 million inhabitants of Southern California.
Today, many of these levees are old—some of them, built by Chinese laborers during
the Gold Rush , are over 150 years old—and have grown fragile. “Between 1900 and
1950, we saw two hundred levee failures up there in the Delta,” said Bea. “Heck, they're
leaking right now.”
One day I drove along the brow of the Jones Tract , a curving levee that collapsed on
a sunny day in 2004 for no apparent reason, causing a tremendous flood that resulted
in $100 million worth of damage. The repaired levee I drove along was potholed and
decrepit. On my left, the land had subsided at least thirty feet below the top of the levee;
on my right, the water had risen almost parallel to the road. The water pressure against
the earthen berm beneath me was nearly palpable.
If a large chunk of levee is breached in the Delta, it would set of a cascading effect:
salt water would surge inland, destroying lives and property and tainting freshwater
supplies for millions of people. Unless drastic measures are taken, Bea said, such a fail-
ure is “inevitable.”
To make his point, he enumerated the many similarities between the Delta and
New Orleans. Each is along the outflow of big rivers—the Sacramento and San Joaquin
Rivers in California, and the Mississippi and its tributaries in Louisiana. Both are set
in wide, flat floodplains, on landscapes of soft earth made rich by the silt of regular
flooding. Both are ringed by old, badly maintained, increasingly infirm levees run by
the Corps. Both, he said, “are ticking bombs.”
Bea is not alone in this estimation. Federal flood experts have characterized Sacra-
mento, which sits at the northeastern edge of the Delta, as the most flood-prone city
in the nation. The levees there, which protect about 60 percent of California's fresh-
water, are vulnerable to earthquakes or major storms. Seismologists have predicted a
1-in-3 chance of a “catastrophic” earthquake in the region in the next fifty years. Such
a temblor could liquidate the earthen levees and transform the Delta to an inland sea.
If a major Pacific hurricane caused waves to overtop and collapse the Delta levees, then
California, the eighth-largest economy in the world, would suffer catastrophically, and
so would the nation.
“In terms of total damage, deaths, and cost, a breach in the Delta would be far worse
than what happened to New Orleans,” Bea said. “This is a national problem. We are due
for a megaflood catastrophe.” Yet he might as well be shouting into the wind.