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Is New Orleans Safe? BP and the 5th Anniversary of Katrina

Posted: 08/27/10 02:19 AM ET

The BP oil spill has one silver lining: It brought attention to the national importance of the Gulf of Mexico, and it will provide some resources to fix its problems. But the issue goes beyond the spill. The fifth anniversary of Hurricane Katrina reminds us of an even more basic question about the region. The question: Is New Orleans safe? If it isn't, at stake could be not only domestic energy production but an inland port system stretching from Pittsburgh to Tulsa.

To answer the question, one needs to know what has been done, how one defines "safe," and what needs to be done.

First, federal, state and local governments committed roughly $14 billion to protect the city against a so-called "100-year flood." Last month the final construction contract for that work was signed. But how safe will that make New Orleans?

The fact is, the 100-year standard, used throughout the United States, is the lowest such standard in the developed world. It is also dangerously misleading terminology. As the Midwest learned in 1993 and 2008, "100-year protection" does not mean an area is safe for 100 years. A "100-year flood" is simply one with a 1% chance of striking in any single year. Over a longer period of time, those odds go up. Over the life of a 30-year mortgage, there is a 26% chance a flood will hit that exceeds the protection. Over the course of a century, there is actually a better than 60% chance that a storm surge will strike that will overtop the protection. What happens then?

In that event, if the system around New Orleans holds, it will function much like the walls of a bathtub, with water pouring over the top. For a peak hurricane storm surge, that overtopping will last only for a few hours. That would create a problem -- flooding in low areas that pumps can empty in a few days. But if the walls breach, as happened in Katrina -- when design flaws made flood walls collapse even when not overtopped -- the ocean will keep pouring into the city even after the storm passes. This happened in Katrina. A second such catastrophe might well kill the city.

So, will the system hold next time? The US Army Corps of Engineers is confident that the new system will survive and continue to function up to and beyond the storm surge of a so-called 500-year flood, one with a 0.2% chance of hitting in any given year and a 12.5% chance of hitting over the course of a century. A 500-year event would flood the lowest parts of the city to a considerable depth, but it would not be catastrophic. (At its worst, where it hit the Gulf Coast, Katrina's storm surge was equivalent to a 400-year event, although the surge that flooded most of New Orleans was less than a 100-year event; again, poor design of the flood walls led to the disaster. The Corps of Engineers designed the flood walls that failed, but there was no review of the work. This time the design and construction has been reviewed by numerous groups inside and outside the Corps, and it should function as designed.)

Still, storms arise greater than even the 500-year standard. Holland protects itself against a 10,000-year storm. How can New Orleans' protection be increased? And-- the elephant in the room-- can the city survive rising sea levels?

First, 10,000-year protection is probably not attainable. Holland can do it only because North Sea storms are far less powerful than Gulf storms. In New Orleans it would be too expensive, and may not be achievable, even with unlimited funds. But that does not mean nothing more can be done. The protection system around New Orleans must be made resilient enough to survive at least a 1,000-year event -- not to fully protect the city, just to prevent the free entry of the ocean into it. Again, this represents the difference between a problem and a catastrophe, the difference between no lives lost and thousands lost.

Second, the coast must be restored. This both a national need and a national responsibility. In the last sixty years, 2,300 square miles of Louisiana have melted into the ocean. That's an area larger than Delaware. If you put Delaware between New Orleans and the sea, the city wouldn't need any levees. And the erosion continues.

What's caused it? A combination of factors. Few people realize that six massive dams built in Montana, North Dakota, and South Dakota to provide flood protection, irrigation, and hydro-electric power have deprived Louisiana of one-third of all the sediment the Mississippi River used to carry. The loss of that sediment has been a major cause of coastal erosion. The shipping and energy industries are other major contributors. The federal government dug large shipping channels, which allowed salt water intrusion and killed marsh, while the oil and gas industry dug 10,000 miles of canals through the marsh, every inch of which also brought salt water in. The BP spill will cause further erosion as oil-covered marsh dies, although it is not yet clear how much loss will result.

This lost land used to serve as a buffer against storms in two ways. It absorbed some storm surge -- for every linear mile over which the surge traveled, its height is reduced from four inches to a foot. More importantly, it cuts down on wave energy. This is enormously important: protection against a 100-year storm surge actually provides complete protection against the "still-water" elevation of a 500-year storm as well.

Finally, restoring the coast will itself help protect the city against sea level rise. The marsh is alive. If given fresh water and sediment from the river, it will adjust, rising with sea level. From this perspective, New Orleans is actually better able to deal with sea level rise that places like New York, built on rock.

Third, the city itself needs to change the way it deals with water inside the levees. This issue is rarely discussed, and the previous mayor, Ray Nagin, completely ignored it. Much could be done, and more is involved than simply raising homes several feet. For example, using permeable pavement -- instead of having all rain water run off -- could minimize further sinking of the land, and might even raise the elevation of parts of the city. Such issues could be turned to the city's advantage. Cities around the world all face rising sea level. Developing water-related technologies could become a green gold mine.

Where will the money come from? As far as what happens inside the levees, the city should be responsible. But as for the coast, BP is responsible for restoring damaged areas; money for that should provide necessary start-up capital. In addition, the EPA can impose up to a $4,300
fine on each of 4.9 million barrels, and that fine should be directed to helping the entire Gulf Coast.

There is also another potential source. Since the 1920s, national policy has recognized that oil and gas production comes at a price. To "relieve social or economic impacts occasioned by" this production, the federal government gives inland states 50% of revenues from such activities on federal land. Last year Wyoming alone received $1.3 billion from this source.

Louisiana has suffered immense damage from oil and gas production on off-shore federal land, and the federal government has received $165 billion in off-shore drilling revenues. Yet until 2006, the federal government gave Louisiana nothing. After Katrina, Congress did give
Alabama, Mississippi, Louisiana and Texas, the Gulf states that allow off-shore drilling, a 37.5% share of revenue from new off-shore wells. Louisiana passed a state constitutional amendment requiring all this money to go to coastal restoration or flood protection. But it capped the total at $500 million divided by those four states and delayed any substantial money until 2017; this year Louisiana will get only $400,000 from this source. Congress should treat all states the same and lift the cap, cancel the delay, equalize the revenue share, and give it on existing wells, not just new ones.

Do it now. The time to fix the Gulf Coast is now.