In other words, if a severe hurricane struck, the city's
flooding and abandonment was not what would happen if the
plan failed. It was the plan.
New Orleans is built between a lake, a river, and the
Gulf of Mexico, and it is lower than the surrounding waters.
It was kept dry by an extensive system of levees and pumps.
That system was itself contributing to the slow subsidence
of the city.
The levee system was largely designed in the early 1960s.
By the standards of their day, the levees were built
conservatively, but within certain constraints. In
particular, they were built to withstand a Category 3
Hurricanes come in two jumbo sizes: Category 4 and, most
severe but rarest, Category 5. A storm of either magnitude
could deliver a surge that would overtop or breach the
levees. The city would be flooded, to depths as great as 20
feet. It would become a lake. Much of it would be destroyed,
and many people would die.
of this was well known. Press accounts and public officials
have been quite open about it for years. "Evacuation is the
only way to protect New Orleanians,"
reported the Philadelphia Inquirer last year.
It quoted Terry C. Tullier, the New Orleans director of
emergency preparedness, as saying, "It's only a matter of
time." Col. Peter Rowan, the commander of the New Orleans
District of the Army Corps of Engineers, told the
Inquirer that the city was "at the mercy of chance for
the foreseeable future." Media coverage was rife with such
What could be done? "It's possible to protect New Orleans
from a Category 5 hurricane," Al Naomi, a senior project
manager with the Corps, told the Inquirer. "To do nothing is
tantamount to negligence." In that interview, he estimated
that hurricane-proofing the levees and building floodgates
at the mouth of Lake Pontchartrain might cost $1 billion and
take 20 years. In other interviews, Naomi estimated the cost
at $2 billion to $2.5 billion and said the project could be
completed in three to five years.
"The point is to eliminate that storm-surge threat with
one of these plans," Naomi told Riverside, a Corps of
Engineers magazine. "The philosophy of what we do during a
hurricane would change. We could spend more time protecting
our homes and less time trying to get out of the city in
these desperate evacuations."
reports the Chicago Tribune, Congress
authorized the Army Corps to conduct a $12 million study to
determine the cost of protecting New Orleans. But the study
was not set to get under way until 2006, and it has so far
received funding of only $100,000 to $200,000. "It was not
clear why the study has taken so long to begin," the
Tribune reported. Meanwhile, Congress and the White
House consistently and sharply cut requests for
Katrina came ashore as a Category 4 storm. The levees
failed and the city, only partially evacuated, was swamped.
"The intensity of this storm simply exceeded the design
capacity of this levee," Lt. Gen. Carl Strock, the commander
of the Corps of Engineers,
told reporters on September 2.
Told so barely, the tale suggests shocking imprudence.
But hindsight is 20/20. Remember, the odds of a Category 4
or 5 hurricane hitting New Orleans any given year were
small. Strock told reporters, "We figured we had a 200- or
300-year level of protection. That means that an event that
we were protecting from might be exceeded every 200 or 300
years. So we had an assurance that, 99.5 percent, this would
be OK. We, unfortunately, have had that 0.5 percent activity
Remember, too, that reinforcing the levees was a
multibillion-dollar project. An ancillary project to restore
the protective marshes of the Mississippi Delta, which would
have reduced the force of storm surges reaching the city,
would cost something like $14 billion over three decades.
For that kind of money, there are always competing
priorities, some of them urgent.
The question, then, is not whether the failure to improve
New Orleans's flood protection was a mistake in
hindsight—obviously, it was—but whether it was a reasonable
choice in foresight, based on the probable odds and costs as
they appeared at the time.
Weighing low-probability, high-cost events is, as it
happens, something economists and engineers know a bit
about. W. Kip Viscusi, an economist at Harvard Law School
and the editor of the
Journal of Risk and Uncertainty, points out that
the Corps of Engineers was among the first to develop and
apply what has become a common cost-benefit template.
Using the more cautious of Strock's figures, assume the
odds are that a storm surge would overtop or breach the
existing New Orleans levees once every 200 years. This
seems, if anything, optimistic, given that Category 4 storms
hit the city in 1915 and 1947; that a Category 5 storm
(Camille) narrowly missed in 1969; and that the devastating
Katrina itself was not a direct hit. Still, assume it.
Assume also that officials could reasonably expect the
city's inundation, abandonment, and partial destruction to
cost, ballpark, $200 billion in direct and indirect economic
In any given year, then, figure that the expected
economic cost of the swamping of New Orleans is $1 billion
(divide the $200 billion cost over 200 years). A $2 billion
levee project could be expected to pay for itself,
probabilistically speaking, in two years; a $14 billion
Delta restoration project, in 14 years.
But wait. New Orleans's 200-year flood might take place a
century from now instead of right away (remember, this
analysis is from a pre-Katrina standpoint), and money lost
in the future matters less to us than money lost today. At
an interest rate of 3 percent, Viscusi says, the present
value of averting $1 billion in expected annual damage
forever is $33 billion; at 5 percent, $20 billion; at 10
percent, $10 billion. Any of those numbers is higher than
the estimated cost of hurricane-proofing the levees, and all
but the smallest are higher than restoring the Delta.
Now, recall that those calculations reflect only tangible
monetary cost. They do not account for inconvenience, pain
and trauma, lives uprooted, and, above all, lives lost. Even
a superbly organized evacuation would leave thousands of
people behind. Moving nursing home patients, emptying
hospitals, and losing control of the streets are dangerous
at best. To all of which, add the psychic and cultural blow
of leaving one of the country's most historic cities an
Strock told reporters that decisions about the levees
were based on "whether it's worth the cost to the benefit,
and then striking the right level of protection." Unless one
uses very optimistic assessments of hurricane odds and
economic costs, and also places a low value on human costs,
New Orleans did not strike the right level of protection.
Even in foresight, Naomi's characterization of New Orleans's
vulnerability as "tantamount to negligence" appears
justified. A far larger flood-prevention program should have
been under way.
"This was not a close call," Viscusi says. "It's a
no-brainer that you do this."
The immediate problem is to identify and bury the dead,
tend to the refugees, and decide whether and how to rebuild.
("Whatever rebuilding is done in New Orleans, nothing very
fancy should go there," says Richard A. Posner, a federal
appeals court judge and the author of last year's book
Catastrophe: Risk and Response.) After that should
come a revision of America's disaster strategy no less
sweeping than the post-9/11 revision of America's security
For example, Congress should create an independent
Disaster Review Board to perform and publish an annual
inventory of catastrophic vulnerabilities, highlighting in
red all the places where, as in New Orleans, more prevention
or mitigation makes sense. The board should prioritize
spending and send an overall disaster budget to Congress
every year for an up-or-down vote, forcing politicians to
confront the issue. If population centers lie over the San
Andreas Fault, in the shadow of Mount Rainier (an active
volcano that could devastate the Seattle area), or on the
floodplains of the Mississippi, the disaster board should be
able to propose protecting them, requiring them to protect
themselves, or encouraging them to move.
If there is another New Orleans out there, the public
should know about it and should have to think about it.
Katrina should change American habits of mind forever.