On Thursday, the White House asked for another $1.5 billion to rebuild New Orleans' levee system, roughly doubling the federal commitment. Following a background report, Donald Powell, the federal coordinator for Gulf Coast recovery, explains how the added funds will be used to strengthen the levee system.

MARGARET WARNER: The Bush administration's pledge to rebuild the city's levee system with double the money originally promised was quickly endorsed by New Orleans Mayor Ray Nagin.

At the White House today, the mayor said the new plan should reassure former residents that it's safe for them to return to rebuild their lives.

MAYOR RAY NAGIN: I want to say to all New Orleanians, to all businesses: It's time for you to come home. It's time for you to come back to The Big Easy.

We now have the commitment and the funding for hurricane protection at a level that we have never had before. These levees will be as high as 17 feet in some areas. We've never had that.

These levees will be fortified with rock and concrete. We've never had that before. This system will have a pumping station, or pumping stations that are near the lake and that have the backup systems that we only dreamed about.

This commitment, this action today, says come home to New Orleans.

MARGARET WARNER: And with me now to explain what today's announcement will mean for the safety of New Orleans is Donald Powell, the federal coordinator for Gulf Coast Recovery and Rebuilding. He's also chairman of the Federal Deposit Insurance Corporation. And he made the announcement today at the White House.

And Mr. Powell, welcome.

DONALD POWELL: Thank you.

MARGARET WARNER: All right, what are you going to be able to do for the extra money that was announced today in terms of rebuilding the levees?

DONALD POWELL: Well, this is the second phase, Margaret, of the president's initiative to rebuild the levees stronger and better. And the second phase includes, as the mayor outlined a moment ago, it includes three areas.

First of all, it includes closing the three internal canals. And it also includes arming the existing canals with concrete and stone to make them much, much stronger.

And the third component is, is rebuilding pumping stations at the mouth of the canals where the water will flow back into the lake.

One thing I might add also is there are $250 million committed to restoration of wetlands. And there is a long-term study part of that, that the commitment is in excess of $4.5 million to study the entire hurricane protection agenda.

MARGARET WARNER: So if you were talking to the people in Betty Ann's piece and they were wondering how safe will New Orleans be next June when hurricane season begins, what would you tell them? How much will have been done?

DONALD POWELL: Next June the target is to do the first three components of the president's initiative which will cost about a $1.5 billion. And that includes assessing the deficit in the design and construction and repairing those -- at the same time repairing the breaches of the levee system; and more important, is bringing the height of the levee systems back to pre-Katrina design. That's very important.

MARGARET WARNER: So in layman's terms will it be basically at pre-Katrina levels?

DONALD POWELL: By June 1; that's the target date.

MARGARET WARNER: But not able to withstand a Katrina-style hurricane?

DONALD POWELL: Well, hopefully within two years with the second phase of what was asked for today by the president and the commitment that within two years it will.

MARGARET WARNER: Explain one of the elements of the new -- of the new money today. I think most people can understand arming the -- armoring the levees or whatever, and new pumping systems. But when you talk about closing these three interior canals in the city, what will that do?

DONALD POWELL: Well, that will again enable the water not to be in the canals and overlap. That was part of the flooding. So with the pumping stations all the water with them being closed, all the water will not flow into the canals and there will be a gate and a pumping station that will flow the water back to the lake.

MARGARET WARNER: So when you all today at the White House were saying that it wouldn't prevent all flooding, but catastrophic flooding, how would you prevent catastrophic flooding?

DONALD POWELL: Well, that's really the second phase of it. And it is really part of the first phase. First of all, the levees will be higher than they have ever before and, again, they will have the armoring, which will make them much, much stronger and not susceptible to breach.

And then also when we close the canals the water will not flow in there and the pumping stations will get it back out.

MARGARET WARNER: Now the -- as you know, Louisiana officials originally had wanted the federal government to commit to building a system that would guard against the most catastrophic kind of hurricane, a Category Five.

Yet today despite many questions to all of you at the White House you were not willing to commit yourself to a Category Four or a Category Five, why not?

DONALD POWELL: That is what this study is about. This study is going to look at the entire hurricane protection, which will include more than just levees, and will answer the question that you just posed: Should we do something different? Should we increase the height? Should we do something different with the canals. The pumping stations, and more important, how do we address the wetland areas?

So this study should be completed within a year-to-year and a half and we'll answer that question.

MARGARET WARNER: Well, Mayor Nagin said today the science doesn't really exist now to know what to do in terms of going to a Category Five. Is that right?

DONALD POWELL: You know, I am not sure but again, this study will answer that question. This study will seek to the resources of the best scientists in the world that deal with this particular issue. And I think we should be governed by that science and I know we will be governed by science.

MARGARET WARNER: All right. So just to recap, by next June what you are saying is at least you will be back to pre-Katrina levels with some improvement?

DONALD POWELL: That's true.

MARGARET WARNER: And by the end of year two you would definitely be able to withstand a Katrina-strength hurricane?

DONALD POWELL: That's true. The levees will be better and stronger than they have ever been in the history of New Orleans.

MARGARET WARNER: Now the question is: You said the Army Corps of Engineers is going to be in charge of this.

DONALD POWELL: Right.

MARGARET WARNER: Who is the federal government is going to oversee their work and the contractors they hire -- because as you know a lot of the outside experts who looked at what happened said in the end the waters didn't come over those levees; those levees structurally failed; they leaked and they crumbled?

DONALD POWELL: Well, there's oversight by the United States Congress and then also the --

MARGARET WARNER: But I mean the congressman, with all due respect, they aren't down there; they aren't structural engineers.

DONALD POWELL: I understand, but they have IG's; they have an inspector general that will look at the scope of the work, make sure there is no fraud or waste involved in that.

MARGARET WARNER: I mean, if you were talking to these former New Orleans residents, what else could you tell them to give them confidence that the same outfit that brought them the levees that didn't withstand the hurricane really are equipped to do it right this time?

DONALD POWELL: Well, some of that was -- some of that was as a result of deterioration in the levees because of settling and some other erosion and then maintenance perhaps was not as good as it should have been during that period of time too.

But I have lots of confidence in the Corps. I think the Corps represents some of the best engineers that we have in America.

MARGARET WARNER: But is your office adding any kind of extra, I hate to say layer because it just sounds like more bureaucracy, but element of oversight, of scrutiny on this very essential question?

DONALD POWELL: No, that is not what we are about. We do not serve in that capacity.

MARGARET WARNER: So it's up to the Army Corps of Engineers?

DONALD POWELL: Right.

MARGARET WARNER: One point today in answer to a question you said, and I want to get the exact quote, you said that the federal government is committed to building the best levee system known in the world.

Now we've talked to a lot of engineers. And the example they always use is the Netherlands, which back in the 50s realized their whole country would be swamped unless they did something.

Their test, their standard is they built a system they say can withstand a storm that comes along once every 10,000 years. Is that what you are committing to?

DONALD POWELL: I'm not sure that we can ever build a levee system that will deal with Mother Nature. But we can go from past experiences. And we can do the best with the science and the technology that we have.

And that's what the corps is doing. The corps is committed to doing that. And again this levee system will be better and stronger than we've ever had in the history of New Orleans.

MARGARET WARNER: And the money announced today, which is $3 billion total, how far will that get you? Does that get you to next June, or does it take you through the second year?

DONALD POWELL: It takes you through the second year.

MARGARET WARNER: All right, thank you very much, Mr. Powell. Thanks for being with us.

DONALD POWELL: Thank you.