Levees Fixed, but City
Still at Risk
October 03, 2005 — By Ted Gregory, Chicago Tribune
NEW ORLEANS — The last of the brown,
festering stew that invaded New Orleans after Hurricanes Katrina and
Rita was being pumped back into the Industrial Canal this weekend.
The breached levees that allowed all that water to rush into the city's
most impoverished and low-lying neighborhoods are fixed. For now.
But two months of hurricane season are ahead, and the temporary fixes
provide New Orleans with less protection than it had before Katrina.
Plans for further levee restoration merely will bring New Orleans the
protection that existed before Katrina, a level that most would contend
came up lacking.
Getting that far will cost taxpayers $1.6 billion.
Going further--protecting New Orleans from another hurricane like
Katrina that packs winds of up to 140 m.p.h.--is a complicated,
multibillion-dollar endeavor that could last decades. And it involves
more than enhancing the earthen, steel and concrete barriers that helped
convert a marshy French settlement into a topographical bowl over the
course of nearly three centuries.
Building taller levees would help. But for starters, that would require
the acquisition of more land for a wider base to accommodate the levees'
height, and years to allow for building the structures in phases to
allow them to naturally settle.
Some U.S. Army Corps of Engineers leaders are urging a look at tidal
gates, retractable floodwalls that would emerge from the levees when a
storm surge threatened. The Corps of Engineers also has pitched a plan
to restore coastal Louisiana, which--with land providing a form of
friction--would slow the nightmarish and powerful churn of hurricanes.
The cost of that plan is estimated at nearly $2 billion.
Regardless of what method engineers come up with, they must contend with
a few natural complications. Most of New Orleans is below sea level, and
it's sinking. In addition, an average of 60 inches of rain falls on the
city every year, about 24 inches more than Chicago receives.
Then there's the human component. Some experts are urging that those
low-lying, waterlogged neighborhoods, home to a population that largely
had nowhere else to live, should be cleared and converted to wetlands
and flood retention areas.
"It's going to be a highly complicated project to sell to people," said
Craig Colten, a geography professor at Louisiana State University and
author of "An Unnatural Metropolis: Wresting New Orleans from Nature,"
published this year.
Other than building the levees to pre-Katrina conditions, no formal
decisions have been made about enhancing New Orleans' hurricane
protection. For now, the Army Corps of Engineers is focusing on cleanup
and restoration. The agency has put together a forensic task force to
examine what failed Aug. 29-30, when Katrina storm surges estimated at
15 feet blew seven breaches in, or simply overtopped levees along the
17th Street, London Avenue and Industrial Canals, three main channels
from Lake Pontchartrain on the city's north side.
Army Col. Duane Gapinski, a West Point graduate based in Rock Island,
Ill., is responsible for ridding the area of surface water and
rebuilding levees to about 10 feet above sea level. He said engineers
have three fundamental theories about what caused the levees to fail,
and three others--one favorite of the media, a conspiracy theory and one
that the engineers like to trot out for fun.
One of the fundamental theories is that the sheer power of the storm
surges in the channels hammered the levees and shoved over the estimated
60 feet of concrete and steel floodwall partially embedded in each earth
levee.
Another theory holds that storm surge water flowed over the floodwall,
cascaded down the other side and scoured the base of the levee, causing
the wall to fall. The third is that downward pressure forced a column of
water through the floor of the canals and the water came up on the other
side. The water then loosened base material from the levees and their
embedded steel "sheet piles," causing the floodwalls to topple.
But Gapinski and other corps officials have been getting questions on
other theories. The media favorite? A runaway barge gashed the
Industrial Canal wall. Gapinski noted that no such gash was found.
Significant scouring on the backside of the levee was.
The conspiracy theory? That New Orleans' leaders orchestrated breaches
that brought water into the impoverished neighborhoods to spare flooding
in the city's white, more exclusive neighborhoods. Brig. Gen. Robert
Crear, overseeing the corps recovery effort in New Orleans, said he has
seen no evidence of that.
And, the joke: Somebody got a snapshot of an alligator swimming along
the breach at the 17th Street Canal. Gapinski and his crew joke that the
critter chewed the gouge through that levee.
That tale may be another twist in the lore of levees, which have been a
part of New Orleans since the French started building them in 1719. Less
than a decade later, a colonial law required all property owners to
build levees along the front of their property.
When Louisiana became a state in 1812, levees extended about 130 miles
on the east bank of the Mississippi from New Orleans, and about 200
miles on the west bank, said Colten, the LSU geography professor.
From that time, levees continued to grow in number and size, typically
after ferocious storms. As they rose and multiplied, so did the chances
of flooding, Colten noted. The levees cut off the Mississippi River's
natural runoff into bayous and other low-lying areas, he added.
Whatever the reason, the result was Gapinski's logistical headache.
Working from 6 a.m. to 11 p.m., in the days after Katrina he ordered
helicopters to drop thousands of giant sandbags--each weighing 3,000 to
7,000 pounds--on the breaches. He directed crews to pump water from
neighborhoods back into the canals.
It succeeded, until Sept. 24, when Hurricane Rita dumped rain on New
Orleans, forcing water over a repaired breach on the Industrial Canal
and reflooding the waterlogged Lower 9th Ward. The repairs and pumping
resumed.
By Wednesday, Gapinski said, more than 95 percent of the water was out
of the metro New Orleans area and still-flooded areas farther south
should be dry by the end of October.
Shoring up repaired breaches is progressing well, Gapinski said. The
goal is to rebuild the levees and floodwalls to 10 feet above sea level
by Dec. 1. Gapinski's successor is to raise them to 14 feet by June, the
start of the next hurricane season.
Gapinski said he expects to complete his mission on time-- as long as
the weather cooperates. "It's going to depend a lot on what storm comes
through," he said. "If we get hit head-on by a Category 3 storm, we're
hosed."
As for whether to boost protection to withstand a Category 5 hurricane,
it depends on spending versus probability of risk, Gapinski said.
The politicians are taking a close look at the issue. On Wednesday, the
House Energy and Water Development Subcommittee met with Army Corps of
Engineers leaders in Washington to discuss how and when New Orleans will
rebuild its water control infrastructure--and how much the government is
willing to spend.
"I'm very concerned that we are going to rush into rebuilding mode, at
the urging of local authorities," said Rep. Mike Simpson (R-Idaho), a
member of the subcommittee, "and put people and taxpayers right back in
harm's way. Not one dime of taxpayer money should be spent to rebuild
infrastructure, or anything else for that matter, in areas that will
remain significantly below sea level and be exposed to massive flooding
again in the future."
Colten, the professor, agreed. He predicted that New Orleans will become
a smaller city. The lowest-lying areas should become open space for
flood retention, Colten said. Higher areas of the city should increase
housing density to hold more people.
"If we can convince these citizens not to battle to go back into harm's
way, they can lead a safer life, a happier life," Colten said. "But we
need to take great care to deal with the human element."
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Source: Knight Ridder/Tribune Business News |