Levees Fixed, but City Still at Risk
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