Lessons Learned from Katrina: How Can Engineers Apply Them for the Future?

[Moonbear]

I just wonder why they don't think about those underwater city project?
because no matter what the government do, another hurricane will still come, the place will be flood again... the best thing to do is to build underground or under water city...

Can you expand on what you mean by this?

At the least, it seems some of those houses, if rebuilt in the same locations, should be put up on stilts as houses are in other coastal/flood-prone areas. (For an example, see the pictures on this site: http://www.amazingplans.com/beach_pilings_style_house_plans.html )

 

[Andre]

Sorry that I did not scrutinize this thead about what has been said but I think I have some fresh information comparing the Dutch way of fighting the sea with the sad fate of N.O.

Dutch water engineers are on side now and their first impression was: a disaster waiting to happen. The Levees were designed to withstand a cat 3 storm, with a mean life of 30 years worth of weather extremities . The Dutch dams are designed to hold up for ...10.000 years. Yes of course there are no cat 5 hurricanes here in the Netherlands but the 1953 flood combining a westery orkan of 12 beaufort with highest tide caused a major disaster. So it took some 30 years to complete the most powerful defence against the sea. Have a look

A New Orleans Levee:

http://gpc.edu/~pgore/myphotos/neworlen/levee1.gif

http://gpc.edu/~pgore/geology/geo101/hydro2.htm

compared to the Dutch "Deltawerken":

http://www.coachdriver.com/countryinfo/netherlands/image/grevelingen.jpg

resisting the pressure of water is not about the height of the levee but it width. You need at least 100 yards or something not the mere ten yards in N.O. That will simply be washed away.

In America everything is bigger and better, is the standard saying in Holland. However this is not about the pumps. The Dutch engineers were shocked about the size and capacity of the pumps designed to balance the water levels. Dwarfs compared to what is installed here. No wonder that it proves to be quite difficult if not impossible to get the area dry again.

So what caused the Katrina disaster? The buildings in N.O seem to have withstand the wind forces quite well, but their feed are wet. Why were the levees quite chanceless against a cat 4-5 storm? Poor politics? I fear the the worst but if the same greenies that shout "climate change" now also had prevented the levees from being upgraded in the past, to preserve nature, then we are sure that mankind is digging it's own grave.

Furthermore I'm convinced that our "deltawerken" would have resisted Katrina with flying colors.

 

[Astronuc]

Shortcuts alleged in building levees
USATODAY.com

WASHINGTON - Several of the levees that flooded New Orleans may have been built with shoddy materials or by contractors who took shortcuts to save money, an investigator told Congress Wednesday. About a dozen people, including engineers and contractors, made the allegations of poor workmanship in recent weeks to investigators probing the levee failures, said Raymond Seed, the head of a National Science Foundation team examining the levees.

Preliminary report - http://hsgac.senate.gov/_files/Katrina/Preliminary_Report.pdf

from - http://news.yahoo.com/fc/US/Hurricane_Katrina/ (Nov 3, 2005)

About a dozen people, including engineers and contractors, made the allegations of poor workmanship in recent weeks to investigators probing the levee failures, said Raymond Seed, the head of a National Science Foundation team examining the levees.

Seed would not identify the tipsters and he cautioned that the allegations may ultimately have nothing to do with the levee disaster that led to hundreds of deaths. But he said that investigators are taking the tips seriously and intend to turn them over to federal officials.

"What makes us nervous is we're hearing multiple accounts," Seed said after testifying before the Senate Homeland Security Committee. The National Science Foundation, which gave Seed a grant to investigate the levees, is an independent federal agency charged with promoting science and the nation's welfare.

The complaints focus on two canals where levees topped with flood walls were built in stages over the past 15 years. One of the claims is that contractors used steel sheets - which were driven into the levees to prevent water seepage - that were shorter than what was called for in designs. If true, that could have made the levees weak and prone to failure.
Other tipsters complained that inferior materials, such as porous soil, were used to construct the levees.

Robert Bea, another University of California, Berkeley professor working with Seed, said in an interview that he talked on the phone with two women who said they had specific information from their late husbands on construction shortcuts taken on the levees. Seed said other investigators received similar complaints.

He wants the Army Corps of Engineers, which oversaw design and construction of the levees, to dig up portions of them to make sure they were built properly.

A preliminary report issued Wednesday by Seed's group and an American Society of Civil Engineers team said key levee failures on the canals near Lake Pontchartrain in New Orleans occurred because water oozed beneath the steel sheets and pushed aside the soft delta soil.

The levees were supposed to be able to withstand water heights seen in Hurricane Katrina, which hit Aug. 29. Investigators have not pinpointed whether designs were inadequate or the levees were built improperly.
Seed was joined by the heads of three other groups investigating the levee failures. The investigators raised questions about poor federal and local oversight of the levees, steadily decreasing budgets for the Army Corps of Engineers and decades of safety compromises.

http://en.wikipedia.org/wiki/Levee_..._in_New_Orleans_(following_hurricane_Katrina)

 

[Astronuc]

I fear the the worst but if the same greenies that shout "climate change" now also had prevented the levees from being upgraded in the past, to preserve nature, then we are sure that mankind is digging it's own grave.

Greenies had nothing to do with poor quality of the levees - they were most built before the environmental movement took off. Rather, corruption and greed on the part of some in government and some in the construction industry, and also the insufficient funding from the government (again due to politics)

Furthermore I'm convinced that our "deltawerken" would have resisted Katrina with flying colors.

I would agree with that.