Hurricane Isaac & New Orleans

[Arisia]

And maybe avoid building cities below sealevel in a hurricane zone.

Yeah, some sections are below river level on one side, below lake level on the other... so it's actually a bit more complicated than the example of Holland, too.

 

[TragicMonkey]

Maybe the hurricane will take care of all those vampires in their secret underground HQ there.

 

[Checkmite]

And maybe avoid building cities below sealevel in a hurricane zone.

This kind of advice is functionally worthless. New Orleans is a major city; it can't pack itself into a bunch of train cars and relocate somewhere above sea level.

 

[BenBurch]

While I agree with the sentiment, this is hardly the best example of it.

There are 4 interstates in that area: 10, 12, 55, and 59 (plus I-49 if you can get to Lafayette). During evacuations they enact contraflow on all of them (not 49, I think. No hurricanes when I was at University there). Additional infrastructure past that won't help all that much and would likely be wasted in non-evacuation conditions.

Quinn has it right: people just need to leave early enough. That was the biggest problem with traffic pre-Katrina. The evacuation order and contraflow weren't enabled until it was too late.

Yeah, on reflection, you're right. But one thing would help; If we had more passenger rail we would more ability to send in emergency trains and take people out. As long as this is done before the storm hits of course. The loss of the relief train sent during the storm that destroyed the railway to Key West should show that...

 

[Miss_Kitt]

The other big concern is how slowly this storm is moving. And it's big, so a LOT of water will fall before it's finally out of the area. Also, big storm moving slowly has time to push that storm surge for a long, long time...which guarantees that you'll hit high tide with the water coming in. Ugh.

I love living in low drama Washington...oh, except for the occasional earthquake, but those don't happen every year or five!

 

[SezMe]

The loss of the relief train sent during the storm that destroyed the railway to Key West should show that...

As far as I can tell, the Seaboard Coast Line ends in Miami. Did it ever go further?

 

[Travis]

I should also point out that New Orleans wasn't originally below sea level. What happened was the ground underneath the city has dropped significantly as it has dried out over the centuries. So a city that started out as a slight rise in another wise flat marsh (that was the reason the city was built there) is now actually a bowl with much of it below sea level.

 

[HHellpop]

I should also point out that New Orleans wasn't originally below sea level. What happened was the ground underneath the city has dropped significantly as it has dried out over the centuries. So a city that started out as a slight rise in another wise flat marsh (that was the reason the city was built there) is now actually a bowl with much of it below sea level.

Not exactly correct. Yes, Bienville chose the location because it was naturally high ground, following the curve of the river. This is the "crescent" of the Crescent City.

http://en.wikipedia.org/wiki/Jean-Baptiste_Le_Moyne,_Sieur_de_Bienville#Father_of_New_Orleans

Post-Katrina, many of us called this the "sliver by the river"

To the north, over some swamp land, are several natural ridges that were also high enough for building on. These originally settled locations, while certainly some subsidence has occurred, remain at nearly the same elevation as they were when discovered.

http://www.globalsecurity.org/military/facility/new-orleans-elevation2.htm

The parts of the city that are below sea level have always been below sea level. They are the drained swamplands between the natural levee and the ridges. It is these areas that continue to subside at a higher rate than the surrounding naturally high land, which compounds the "bowl" effect.

Pretty quiet here in town now. Nice to see the intensity forecast downgraded again this morning. Still, we're going to get dumped on heavily, which is the real issue with this storm. The drainage pumps can only handle 1" in the first hour, and .5" every hour after that (never did understand how that works). Last I heard, we're expecting 6"-12" inches....

We'll hold the fort down for you, Quinn!

 

[Jaggy Bunnet]

The drainage pumps can only handle 1" in the first hour, and .5" every hour after that (never did understand how that works).

As someone with no knowledge and basically guessing, assume that for the first hour a significant part of the rainfall is absorbed into the ground/other structures and that the drainage pumps are only dealing with part of the total rainfall. As the ground other structures become saturated a larger part of the total runs off and needs to be dealt with by the drainage pumps?

 

[Sam.I.Am]

Still, we're going to get dumped on heavily, which is the real issue with this storm. The drainage pumps can only handle 1" in the first hour, and .5" every hour after that (never did understand how that works). Last I heard, we're expecting 6"-12" inches....

I'd guess that it's one of the following reasons:

1) It takes about half an hour for the flow from the street drains to reach the pumps and fill the sumps and that the pumps maximum capacity is actually rated at 1/2 inch per hour with 1/2 inches worth of sump reserve capacity acting as a buffer. (For example San Francisco has reserve sump tanks that are 2 miles long, 30 feet wide and 20 feet deep that run under the Great Highway but get overwhelmed after a few hours of hard rain.)

2) The pumps can be run safely at maximum for an hour but then they need to be slowed down or they may fail due to overheating (bearings and seals mostly) or something along those lines. This is also common in power plants where they can run at 110% or more rated power for short periods of time before damage from overheating starts to be a concern.

3) After an hour they start to worry about having problems with storm debris either clogging the intakes or being a concern with it damaging the pumps at higher speeds. Not too likely IMO because the pump bodies and rotors are usually pretty tough but maybe they worry about the seals starting to get damaged or they have to cycle through the pumps to clear out the debris from the intakes which places half of them offline at any given time.

Or maybe a combination of those but I think that I listed them in order of probability.

 

[HHellpop]

Well, those are some great suggestions, and I suspect #'s 1 & 2 from Sam.I.Am are most possible. Makes perfect sense - you can't run the engines at Warp 8 for too long. Thanks!

 

[DGM]

As far as I can tell, the Seaboard Coast Line ends in Miami. Did it ever go further?

I believe this is what he was talking about.

http://en.wikipedia.org/wiki/1935_Labor_Day_hurricane

http://en.wikipedia.org/wiki/Florida_Overseas_Railroad

 

[a_unique_person]

http://flhurricane.com/cyclone/showflat.php?Board=tb2012&Number=93835&view=collapsed&sb=5&fpart=1

It's big, it's moving slowly, and it's going to cause a lot of flooding and storm surge.

 

[WildCat]

Much of Holland is below sea level, and the area is subject to flooding, as in 1953. Maybe we need some Dutch ingenuity.

Tell me about all those hurricanes hitting northern Europe.

 

[Sam.I.Am]

http://flhurricane.com/cyclone/showflat.php?Board=tb2012&Number=93835&view=collapsed&sb=5&fpart=1

It's big, it's moving slowly, and it's going to cause a lot of flooding and storm surge.

A more comprehensive link for Gulf Hurricanes. It can get bogged down when these occur so be a bit patient.

http://www.tropicwx.com/

 

[SezMe]

I believe this is what he was talking about.

http://en.wikipedia.org/wiki/1935_Labor_Day_hurricane

http://en.wikipedia.org/wiki/Florida_Overseas_Railroad

Thanks DGM. Noodling around from those links finally lead to this:

The FEC is possibly best known for building the railroad to Key West, completed in 1912. When the FEC's line from the mainland to Key West was heavily damaged by the Labor Day Hurricane of 1935, the State of Florida purchased the remaining right-of-way and bridges south of Dade County, and they were rebuilt into road bridges for vehicle traffic and became known as the Overseas Highway.

So a train went to Key West before a road did. What an interesting little tidbit of Americana.

 

[OrangeCatz]

Here's a Bourbon Street Cam.

 

[Sam.I.Am]

Thanks DGM. Noodling around from those links finally lead to this:

So a train went to Key West before a road did. What an interesting little tidbit of Americana.

Not really surprising when you think about it, there were very few automobiles back then and you have to figure that the planning stages had to start when there were little to no automobiles available to the general public but travel by rail was at one of its high points around that time with a lot of construction geared towards it. A lot of places that we drive to now that involve a water crossing were done by ferry as little as 60 years ago and we still have ferry systems as a backup in the event of the loss of a major bridge in many locations.

 

[Quinn]

17 hours, ugh, that's what I call a learning experience.

It was part one of a two-part learning experience. The second part happened the next summer when, having learned the first part so well, I got myself ready and out of town as fast as I possibly could for Katrina -- so fast, in fact, that I hardly took anything with me, and ended losing very nearly everything I owned when I got 6 feet of water in my place. So what I've learned is, leave early, but take stuff with you and secure what you leave behind too.

Stay safe, Krul!

 

[HHellpop]

It was part one of a two-part learning experience. The second part happened the next summer when, having learned the first part so well, I got myself ready and out of town as fast as I possibly could for Katrina -- so fast, in fact, that I hardly took anything with me, and ended losing very nearly everything I owned when I got 6 feet of water in my place. So what I've learned is, leave early, but take stuff with you and secure what you leave behind too.

Real sorry to hear about that. At the time, I was luckily living at Tchoupitoulas and Henry Clay - well above sea level. Now I live in Broadmoor, near the intersection of Fountainbleau and Napoleon. Right in the middle of the bowl.

I also took 3 t-shirts, 2 pairs of pants, my dog, and my guitar. I think a lot of us thought we'd be out for 2-3 days, then back home. Yeah, lesson learned the hard way.

Stay safe, Krul!

Will do! I still have power and Internet!! It is whipping out there, but so far, my place seems sound. It's been raining, but not too heavily at once so far, so not too much standing water in the street.

Where are you riding it out? We'll have to have a beer when you get back!