Physical effects of Katrina

[Boerseun]

Without being callous or anything, I thought of opening this thread to discuss the physical effects of Katrina. Of course everybody here are sympathetic towards the victims and their family, but I want to limit this to physical issues.

 

To start off with - what would be the long-term effects of skyscrapers having their foundations flooded? Would they eventually start sinking, or warping? Would they have to inspect every building?

 

I'm sure there are lots of other issues that nobody thought of yet - this is the place to raise 'em and discuss 'em.

[Dark Mind]

There are skyscrapers in Mississippi and Louisiana? :lol:

 

Anyway... I'm not sure that would be that big of an issue, most building are constructed to withstand most types of natural disaster. I believe something of concern should be the standing water and bacteria that are now flooding the streets (Most areas are under sea level :) ). That's gonna take some work to get rid of. I predict it will be a month to a month and a half before the area is ready to be lived in again :).

[Tormod]

I am concerned with the environmental effects of Katrina. And if it's only on of several to come, I hope we will see some data which correlates the current events to changes in global weather so that we can find out whether this is related to man-made changes or not.

[Dark Mind]

I believe that the changes will have to be "man made", all that standing water isn't going to evaporate over night, or even in a month :lol:.

[Qfwfq]

what would be the long-term effects of skyscrapers having their foundations flooded? Would they eventually start sinking, or warping? Would they have to inspect every building?

It depends on the ground the foundations are set into. In some floods, buildings have had their foundations destabilized by the water wearing the dirt from under the foundations.

[Boerseun]

In reply to Tormod's post:

 

As far as I understand it, New Orleans was built on a natural wetland/swamp system, that's why it's lower than sea level.

 

In other words, if the whole area flooded, it's a natural occurence. The tragedy is that humans have tried to control the environment and keep water out of what should actually be a swamp. And now we are faced with the results of poor planning.

 

The actual environmental disaster here would be petroleum products floating out of underground tanks, at fuel stations, for example. Bacteria and such that would thrive on spoilt products at flooded supermarkets, in flooded kitchens, etc. would be a transient problem - at some stage their food would be used up and the bacteria would die off. But poisonous chemicals would permeate the ground and cause a monumental disaster for years to come. And I guess the flooded sewage system can't be any fun to live with, either.

 

I've never been to New Orleans - are the houses there mostly brick, wood, or what? And what's it flooded with - river water from the Mississippi, or sea water? Seawater should also increase the salinity of the soil, making it virtually impossible to create gardens in the years to come, whilst river water would actually fertilize it (ignoring the chemicals for a bit).

 

I'm sure that also the roads' foundations weren't designed to withstand prolonged submergence, so in the near future potholes will be an everyday sight.

[Qfwfq]

New Orleans was built on a natural wetland/swamp system, that's why it's lower than sea level.

 

In other words, if the whole area flooded, it's a natural occurence. The tragedy is that humans have tried to control the environment and keep water out of what should actually be a swamp. And now we are faced with the results of poor planning.

Not all that unusual, look at the Netherlands. The worst thing seems to have been the way the situation was handled.

 

Seawater should also increase the salinity of the soil, making it virtually impossible to create gardens in the years to come, whilst river water would actually fertilize it (ignoring the chemicals for a bit).

Depends on how long it remains flooded and whether the water is pumped away or let evaporate. Anyway I think it was freshwater.

[C1ay]

It depends on the ground the foundations are set into.

New Orleans has actually been steadily sinking over the years.

[Qfwfq]

What's the subsidence due to? Hydrogeological equilibrium, plate motion or what?

[C1ay]

New Orleans sits atop a delta made of unconsolidated material that has washed down the Mississippi River.

[Qfwfq]

I'd say that increases the risk of foundations being scoured, if water current has been penetrating around them.

[infamous]

It's possible that the greatest tragedy is yet to come. When we've been fortunate enough to have overcome the social devastation and the possibility for the spread of disease I hope we don,t forget why all this happened. If nothing is done about illconcieved system of levies and low lying areas, to allow the residents to reoccupy the city in the same condition it was in before Katrina hit would be a tragic mistake.

[C1ay]

If nothing is done about illconcieved system of levies and low lying areas, to allow the residents to reoccupy the city in the same condition it was in before Katrina hit would be a tragic mistake. [/font]

Yes. New Orleans is a vital port that connects the U.S. to the world through the Mississippi river. It is a port needed by the U.S. but it reflects the worst of american engineering on a grand scale. I think it might make more sense to widen and deepen the river up to Baton Rouge and turn it into the needed port. Compared to the construction of the Panama Canal this would seem like a small task. We have the ability and the technology, now we just need to use sane engineering requirements.

[Southtown]

Yes. New Orleans is a vital port that connects the U.S. to the world through the Mississippi river. It is a port needed by the U.S. but it reflects the worst of american engineering on a grand scale. I think it might make more sense to widen and deepen the river up to Baton Rouge and turn it into the needed port. Compared to the construction of the Panama Canal this would seem like a small task. We have the ability and the technology, now we just need to use sane engineering requirements.

Dittos. Panama or no, moving the New New Orleans (like that?) up the river would probably be no harder than a rebuild in its current locale, but immeasurably more intelligent.

[Turtle]

As far as I understand it, New Orleans was built on a natural wetland/swamp system, that's why it's lower than sea level.

 

In other words, if the whole area flooded, it's a natural occurence. The tragedy is that humans have tried to control the environment and keep water out of what should actually be a swamp. And now we are faced with the results of poor planning.

 

I've never been to New Orleans - are the houses there mostly brick, wood, or what? And what's it flooded with - river water from the Mississippi, or sea water? Seawater should also increase the salinity of the soil, making it virtually impossible to create gardens in the years to come, whilst river water would actually fertilize it (ignoring the chemicals for a bit).

 

I'm sure that also the roads' foundations weren't designed to withstand prolonged submergence, so in the near future potholes will be an everyday sight.

 

___The broken dikes which flooded most of the city held back Lake Ponchatrain(sp), a salwater lake.

___Poor planning is an understatement. I recall reading about sinking New Orleans in National Geographic decades ago. Good money after bad! Make whatever engineering requirement for river navigation & abandon the rest. The environmental disaster IS the city; get rid of it & let the delta exist as a delta. :lol:

[Buffy]

Well, once upon a long time ago, NO was above water, but what man did was try to "tame" the Mississippi (meatheads! :lol: ) and in order to do so had to build levees. The upshot is that to control it, they had to *raise* the level of the river and the lake *above* where NO was situated.

 

To read an *excellent* treatment of the topic of trying to control that amazing river from the Master of Geology, John McPhee, check out The Control of Nature http://www.amazon.com/exec/obidos/tg/detail/-/0374522596...

 

Cheers,

Buffy

[Buffy]

I think it might make more sense to widen and deepen the river up to Baton Rouge and turn it into the needed port. Compared to the construction of the Panama Canal this would seem like a small task.

Also see Control of Nature for a discussion of some of these issues. "Widening and deepening" is not really an option unless you're really prepared to take out the entire southern part of Louisiana, and I'm sure the developers who want the land that the geologists will tell you has to be left wetland to keep any of it navigable, won't let that happen. The river is already way above its natural level hundreds of miles up stream, and none of that is sustainable over time. You're going to actually be much better off with the major port closer to the mouth of the river, leave lots of delta space and let a lot of the upstream river silt up and forget trying to ship stuff up the river. Its easier and cheaper to put it on trains....

 

Course that means rebuilding NO and trashing Baton Rouge....hmmm, think *that* will happen? :lol:

 

Cheers,

Buffy