Gustav: Testing the Levees in New Orleans

Almost exactly three years after Hurricane Katrina pummeled New Orleans, another tempest is bearing down on the city. Hurricane Gustav grew into a Category 4 monster on Saturday, with 150-mile-per-hour winds that lacerated the western end of Cuba. The storm, which caused scores of deaths in the Caribbean, was expected to weaken before striking the Gulf Coast, most likely west of New Orleans. On Saturday, city leaders ordered a mandatory evacuation, and residents streamed out of the Big Easy in cars, buses and trains. "You need to be scared," New Orleans Mayor Ray Nagin said. "You need to get your butts moving out of New Orleans right now." The storm is also having a political impact. Republicans, haunted by memories of the response to Katrina, are weighing whether to shorten or delay their convention in Minnesota, President George W. Bush and Vice President Dick Cheney have canceled appearances there—and Sen. John McCain and his new running mate, Alaska Gov. Sarah Palin, are expected to stop in Mississippi on Sunday to check on hurricane preparations. In New Orleans, $2 billion worth of upgrades to the city's levees and floodgates have bolstered its defenses, but the city is still unprepared for a so-called 100-year storm—the sort expected to occur only once per century. To learn more about the city's ability to handle another hurricane, NEWSWEEK's Catharine Skipp spoke with Stevan Spencer, executive director of the New Orleans Levee District and chief engineer for the district during Katrina. Excerpts:

NEWSEEK: Were there lessons from Katrina that changed the way the levees are managed?
SPENCER:
At the time there were only a couple of projects that hadn't been done before Katrina and they wouldn't have made a difference, like frontal protection of the pumping stations. However, there are three new pumping stations along the lakefront.

What preparations are underway right now?
Basically we are closing the floodgates. There are 126 in the system and 60 are open for railways and roadways and such. We've closed about 20 so far and by Sunday we will have the other 40 closed so there will be a continuous wall of protection from 15 to 20 feet high around the city. Basically they will finish up closing the floodgates, then ride it out here.

Where is the potential for the most vulnerability?
Everything has been repaired and rebuilt to pre-Katrina levels. It's not at 100-year flood event levels.

Was Katrina a 100-year flood event?
Katrina was a 300-year-plus event. But Gustav shouldn't push in as much as Katrina. This time the West Bank will be the most vulnerable. Rita was more like this as far as wind direction. Like then, water may overtop the levee and flood lower-lying areas like Gretna and Harvey [Louisiana]. There are some monster walls being built along the Harvey Canal--15-foot big, tall T walls--but that still has a ways to go. We have added another three feet by sandbagging about 300 feet of earthen levee on the West Bank, raising it from 12 1/2 feet to over 15 feet.

What will your people be doing during and after the storm?
Our people--Orleans Levee District police and surveyors--will be out monitoring the levees until the winds reach 35 miles per hour sustained. Then after that we will remotely monitor the canal gates by computer. If there is a monster spike in the river gauges--that blows away the gauge--we know that might be a surge. The Army Corps of Engineers will be manning the pumping stations on the lake and will close them if they see a storm surge coming. They still will have the ability to pump the water in the canals filling from the city pumps. We will have mechanics here to fix any breakdowns. After the storm goes through we will be out opening the railroad and roadway floodgates so people can come back into the city.

During Katrina communication was a problem. How are you coordinating with other agencies?
We are having multiple conference calls daily with the other levee districts, DOTD [Louisiana Department of Transportation and Development] and the Army Corps of Engineers. Also we have our police at the EOC [New Orleans Emergency Operations Center].

What will prevent the problems that happened from Hurricane Katrina?
We are better than before Katrina--we've raised the levees and strengthened or replaced the floodwalls. That should help prevent what happened before but we are not at the 300- or 500-year flood mark. When we have a surge buffer on the Chef Menteur and Rigolets passes [the passes between Lake Borgne and Lake Pontchartrain], that structure will give us 500-year flood protection.

Could you please explain the mechanics of the drainage and pumping stations?
It's simple. Whatever falls inside the floodwalls is pumped into the lake or another body of water, through the canals. I'm not sure of the rate but the pumps start pumping a number of inches an hour and the rate slows some as they keep pumping.

Can the floodwalls and gates prevent flooding from a storm surge? How well should the current levee system be able to handle a Category 3 or Cat 4 storm?
A Cat 4 storm from the right direction could cause the surge to overtop the walls. A Cat 5 from another direction may not. There are so many variables to consider. The Corps of Engineers have been running models for days but all we can do is close the flood gates. There are no low spots in the levee so we are going to hunker down and wait for it to pass and then open the floodgates and start inspecting.

Do you expect flooding?
The way it looks now, we don't expect any. Last time, the surge caused the damage. This time it looks like rain will cause any flooding, not overtopping the levees.

What role will tides play?
Lake Pontchartrain has some tide swing but Monday we will be in a 'switching' tide. The tides vary from three-tenths to 2 feet. On Monday we will be in the low tide range so that should absorb a lot of the rain.

Was there one breach during Katrina that played a larger role in the flooding than the others?
The ones on the 17th Street and London canals may have been responsible for as much as 50 percent of the flooding. This time the control structure at the lakefronts should change that. They can see the surges and activate the station while allowing the sluice gates to continue to drain water from the canals.