Nothing's Easy for New Orleans Flood Control 

By JON NORDHEIMER

NEW ORLEANS — Caught between the Mississippi and the long shoreline of Lake Pontchartrain, this low-lying city has long depended on levees and luck. 

Now engineers say those are not enough to protect New Orleans, much of it below sea level, from a devastating flood that could threaten it if a storm surge from a powerful hurricane out of the Gulf of Mexico propelled a wall of water into the lake and the city. 

That event could place vast sections under 20 feet or more of water, engineers and scientists say, with worst-case computer predictions showing death tolls in the tens of thousands with many more people trapped by high water that has no natural drainage outlets. 

"There's no way to minimize the amount of devastation that could take place under such circumstances," warned Walter S. Maestri, director of emergency management of Jefferson Parish, a suburban region with 455,000 residents on the city's western and southern sides. 

Perhaps the surest protection is building up the coastal marshes that lie between New Orleans and the sea and that have been eroding at high rates. But restoration will require time, a huge effort and prohibitive sums of money, perhaps $14 billion, according to a study by a panel from federal and state agencies, universities and business. 

Engineers are considering other ways to protect the heart of the city and provide an island of refuge in the French Quarter and government centers. Though such approaches are less expensive, they come with their own problems. One plan involves walling off an area to keep out water. But where would the wall be built and who would benefit from it?  

Many residents give little thought to such matters, counting on the knowledge that New Orleans has escaped hurricane disaster in the past. 

The most nervous people are those paid to worry about such things, like Dr. Joseph N. Suhayda, director of the Louisiana Water Resources Research Institute at Louisiana State University. Like other coastal researchers, he has been using the latest geological and meteorological data to refine computer models of how different storms would damage the city. 

On a bright spring day with fair skies and no trace of the sultry air that will dominate the weather in the months ahead, Dr. Suhayda and a few colleagues drove city streets 1,000 yards from levees that hold back Lake Pontchartrain. 

At New York Avenue, near the lakefront campus of the University of New Orleans, the car stopped, and the engineer walked over and unfolded a wood measuring stick to its 25-foot length. He planted one end on the pavement and raised it until it was vertical. The other end poked into the sky well above a corner light pole, but it was still well beneath the level of a concrete wall that rose on top of a grassy slope 100 feet away. 

"Behind that," Dr. Suhayda said, indicating the wall, "is a canal that runs into Lake Pontchartrain. Its surface is roughly about the same as the lake's surface." 

In a hypothetical situation projected by his computers, Dr. Suhayda continued, a slow-moving Category 4 hurricane, with winds up to 155 miles an hour, or a Category 5 hurricane with even stronger winds could leave water 30 feet deep on this neighborhood street, which is more than five feet below sea level. Though Category 5 hurricanes are very rare, Camille in 1969 devastated Pass Christian, Miss., just 50 miles east of New Orleans, and killed scores of residents with winds that exceeded 200 miles an hour and a 35-foot storm surge. 

In most areas vulnerable to hurricanes, the water would drain away quickly. That is not the case here.

So city planners and engineers continue to work on ways to improve an evacuation plan for the 1.3 million residents in the metropolitan region and to soften a storm's blow. Most long-term projects intended to blunt a hurricane involve slowing the loss of marshlands. One method calls for additional control gates to let the Mississippi pour sediment-rich water into surrounding lands, a process that would eventually raise or at least maintain their elevation. 

Other proposals are to rebuild eroded offshore barrier islands, erect a wall of levees across much of the lower delta, plug the dredged containership channel that gives the Gulf of Mexico waters easy access to the vulnerable eastern shore of Lake Pontchartrain and help defend that shore with higher flood gates. 

Perhaps the most unconventional is the "community haven" concept advanced by Dr. Suhayda and others in the belief that radical remedies may be necessary to soften a knockout punch by nature. More theory than an organized campaign, it envisions a two-story-high wall with flood gates at crucial intersections to seal off the southern part of the city from a bend in the river at the French Quarter to another one eight miles west. 

If the rest of the city flooded, Dr. Suhayda said, the "island" between the wall and the river's levees could become a refuge for thousands of residents fleeing their homes, as well as preserving the cultural and government center. 

But obtaining the money on the scale needed is far tougher than devising plans, especially if some skeptics dismiss the worst-case predictions as scare tactics to help finance university research or for further environmental intrusions on the coast. 

Researchers, though, say they are not making up the city's potential peril, which arises from geology and history. As tight as a pimento in an olive, most of New Orleans is stuffed between the Mississippi and the lake, and it is settling as fast as the rest of the delta or faster, said Dr. Roy Dokka, a geologist at Louisiana State. 

Although much agonizing has gone into problems of the river, and its metaphoric temperaments have become part of songs and folklore, it is the 300-square-mile lake that troubles him, Dr. Dokka said. 

As New Orleans grew as a seaport, petrochemical hub, tourist destination and cultural phenomenon, neighboring marshes were drained and the levee system expanded to keep the water out of new suburbs and industrial parks, hastening the drying that led to sinking, and making a bad situation even worse. 

Matthew P. D'Agostino for The New York Times

Back