Katrina vs. Tsunami - I'm skeptical.

[jmercer]

Personally, I think they'd be better off either abandoning the city or rebuilding it in such a way that it's flood-resistant.

In example, there's absolutely no reason that building's have to constructed with the main floor (or basement!) at ground level. Many homes on the ocean on Long Island are built on pilings that elevate the homes 15 to 20 feet above ground level. While this is hardly proof against a catagory 4 hurricane, it does protect them from the occasional catagory 3 and lower - while letting the incoming surf stream harmlessly between the pilings.

Now, New Orleans doesn't get hit directly by surf. (Or if it does, then they should bloody well go with plan A - abandonment!) So flood waters - while powerful - won't be a direct storm surge so much as a powerful spill from the levee.

Constructing an elevated city with buildings designed to permit free-flow of flood water would be an intelligent approach; simply rebuilding the city and counting on bigger, better levee's and pumps is the easy way out. Easy, at least, until a Catagory 5 strikes.

 

[kevin]

Now, New Orleans doesn't get hit directly by surf. (Or if it does, then they should bloody well go with plan A - abandonment!) So flood waters - while powerful - won't be a direct storm surge so much as a powerful spill from the levee.

Might as well tell the Netherlands to abandon their entire country then....

New Orleans does not currently get hit by surf, however because of the channelization of the mississippi no sediments are deposited in the delta area (they are now flushed into the Guf). Because of this Louisana has been losing land to the ocean at a steady rate. This has moved the coastline closer to NO and may have worsened this event. Once a hurricane moves on land it loses power, with less land between the ocean and NO the hurricane retained much of it's power.

By the way, the levees broke on the lake side. The lake dumped into New Orleans. What you are seeing in the city is a "levee spill" not storm surge.

 

[jmercer]

Now, New Orleans doesn't get hit directly by surf. (Or if it does, then they should bloody well go with plan A - abandonment!) So flood waters - while powerful - won't be a direct storm surge so much as a powerful spill from the levee.

Might as well tell the Netherlands to abandon their entire country then....

The Netherlands doesn't exist next to a warm-water body that supports and enhances a storm's potency on an annual basis.

New Orleans does not currently get hit by surf, however because of the channelization of the mississippi no sediments are deposited in the delta area (they are now flushed into the Guf). Because of this Louisana has been losing land to the ocean at a steady rate. This has moved the coastline closer to NO and may have worsened this event. Once a hurricane moves on land it loses power, with less land between the ocean and NO the hurricane retained much of it's power.

I know. Which is why I say they should either abandon or rebuild with flooding as a planned occurance.

By the way, the levees broke on the lake side. The lake dumped into New Orleans. What you are seeing in the city is a "levee spill" not storm surge.

I know, which is why I said "Now, New Orleans doesn't get hit directly by surf. (Or if it does, then they should bloody well go with plan A - abandonment!) So flood waters - while powerful - won't be a direct storm surge so much as a powerful spill from the levee."

I grew up in an area directly subject to storm surge and surf - and one that is occasionally visited by hurricanes - even Catagory 4 storms. Part of my education growing up was seeing pictures and getting lectures on the history of Long Island and hurricanes - in fact, the name of my high school football team was "The Hurricanes". Since I grew up on the ocean, weather has always been a fascinating and important topic for me...

Interestingly enough, the Wall Street Journal reported today that there were actually three spills into New Orleans; 2 from levee's and one from a canal who's side had been rammed by a barge. That's the issue with levee's and walls; once breached, you're doomed. That's why they should build the city with the expectation of flooding rather than the hope that it won't happen.

 

[Psi Baba]

Just a few questions:

How long was it after the hurricane hit that the levees failed?

What was the delay between the event and the actual flooding?

I know Lisa made a response to this question as well, but I was attempting to answer this question in another thread and came up this information:

According to CNN.com's timeline of the hurricane

August 29
• 4 a.m.: Hurricane Katrina is downgraded to a strong Category 4 storm.
• 7 a.m.: Katrina makes landfall on the Louisiana coast between Grand Isle and the mouth of the Mississippi River.
• 11a.m. Katrina makes another landfall near the Louisiana-Mississippi state line with 125 mph winds. The storm's daylong rampage claims lives and ravages property in Louisiana, Mississippi and Alabama, where coastal areas remained under several feet of water.
• Two major flood-control levees are breached, and the National Weather Service reports "total structural failure" in parts of New Orleans. A section of the roof of the Louisiana Superdome, where 10,000 people are taking refuge, opens. Many are feared dead in flooded neighborhoods still under as much as 20 feet of water.

In a different article:
http://www.cnn.com/2005/WEATHER/08/31/katrina.levees/index.html

The National Weather Service reported a breach along the Industrial Canal levee at Tennessee Street, in southeast New Orleans, on Monday. Local reports later said the levee was overtopped, not breached, but the Corps of Engineers reported it Tuesday afternoon as having been breached.

This article in the Star Tribune, timestamped August 29, 10:33 pm, refers to levees being breached.
http://www.startribune.com/stories/535/5585674.html

So landfall was recorded in the early morning hours of Monday the 29th, and the first levee breaches occured no later than Monday evening, possibly even earlier. At least two of the three breaches occurred the same day the hurricane made landfall.

 

[Zep]

Given that only a small part of NO has actually been flooded, and that it is going to be rebuilt, I would be recommending that any low-lying area should be built up above the lake/shore level at a minimum. Then there would be no further use for the levees (save ongoing money maintaining them and pumping), and there would be one less future danger (flooding) NO would be likely to face. Raising most types of houses, or moving them aside temporarily, is not particularly difficult nor frightfully expensive.

 

[davefoc]

I think the coming Katrina commission is going to place most of the blame on the Mayor and the Governor, with some on FEMA's tardiness.

Ah, such a pleasant notion. The government cares about the truth and is interested enough in finding out what went wrong so much that it will establish an independent commission to investigate the problems of the Katrina response in an honest non-partisan way.

I don't know exactly where a government like that exists but it certainly isn't like ours. The Bush administration has dug their heals in. No independent commission. Instead we're going to get the Bush led investigation. Of course we can all trust the Bush administration to investigate themselves fairly and provide an unbiased view of the problems, but if we don't trust the Bush administration surely we can trust the legislature to investigate in a fair and unbiased way the problems with the response. The congressman wouldn't just spit out a bunch of partisan jabs without really investigating the issue would they? Oh wait that's what they just did.

So don't hold your breath waiting for a Katrina commision that cares much about the truth.