Sunday, July 24, 2011

Watermark: Practical advice for surviving a flood

Dealing with disasters can be a useful analogy for dealing with life. We try and prevent bad things, but some problems are inevitable. We need to know how to handle when problems do happen. Today we talk about risk management and Kristy has some good advice on what to do if a flood does hit.


Kristy Chandler: I think [risk management] is relevant to all aspects of our lives. The biggest lesson for individuals and communities is to make sure that they do their own risk assessment, and have their own plan in place. And that’s something that’s really being encouraged at the moment in the U.K. because there are just so many [people at risk].  There’s five million properties currently expected to be at risk of different types of flooding, and there’s no way that all of them can be defended and all floods prevented.  There’s a drive for individuals and communities to be aware if they are at risk and come up with their own flood plans.

It’s just being prepared, really. Aware and prepared- that can go to all kinds of aspects of life, doesn’t it? It can be having a fire alarm in your house in case of a fire or insurance if your house was to burn down.  Be aware of the risk and then do something to manage if it was to occur. We’re encouraging community members to have a little flood pack in their cupboard, and if they were to be flooded, they would grab the pack. It might have a blanket and first aid kit in it, and a can of beans, a map showing them where they’re supposed to go. For that kind of thing, we’re really good at fire but we’re just getting there on flooding.

Tom Pagano: That’s an interesting idea, that not all disasters are preventable. You could try to protect yourself but something is always going to slip through, no matter how hard you try.  You could live in a house with iron bars and bullet proof glass but it’s expensive. Besides, you’re not really living a comfortable life in a Kevlar house.

Maybe not the best place for entertaining guests (source)
Original caption: This reinforced concrete safe house is designed to allow someone to control the new hurricane protection gates at the mouth of the 17th Street Canal, even during a hurricane. If it looks like a storm is going to be strong enough to destroy the safe house, the people inside can escape out the back and then the gates can be remotely controlled. Read more

Kristy Chandler: It’s part of the risk-based approach. You can never completely eliminate flood risk because it can always rain more than you expect, and more than you design for.  So you design for something that’s appropriate to the level of consequences. In an area that’s, say, farmland, you may not defend it to a level that’s very high, but a hospital you may want to put extra measures in to make sure it doesn’t flood.

There’s always – even if you do put defenses in– the risk that those defenses will breach.  So, quite often, we’re putting emergency plans in place to respond to flooding if primary defenses fail. That’s another [issue] for flood risk management.

Tom Pagano:  I saw something about this for the Tsunami in Japan. They have natural flood barriers of trees on the shore. The barrier is good for breaking up a medium-sized tsunami. But for something that’s overwhelming, then those trees just become projectiles. Then you have trees rammed into buildings. I’ve seen some astonishing photos.

Japan tsunami damage (source)

Kristy Chandler: The legislation in the U.K. requires you to assess the risk behind defenses.  So even if there is a flood defense against a Tsunami, you need to assess the risk if that was to fail or over-top, and put measures in place to make sure that people would still be safe.

Tom Pagano: Do you have any practical advice for if you’re ever in a flood? Someone asked me the other day if I knew what to do if I had warning of a meter of water in my living room. I’m not sure I know the answer to that… and I’m a hydrologist!

Kristy Chandler: You don’t want ever want to walk through flood water.  One of the very dangerous things is that manhole covers lift, and if you’re swimming or walking through flood water, you can get sucked into the sewer… Obviously, that’s going to be the end for you because there’s no oxygen. [Walking through a flood is] the thing you just don’t want to do. 

If you’ve got a double story house, then you might want to go to the top floor. In Queensland recently they camped on the roof. You would probably want to evacuate the area if you don’t have a double story house, before the flood water hits. And if you can’t evacuate in time, go for the highest point and call someone, if you can.  Try and get some kind of a message to people to come and rescue you.

Not the kind of thing you want to see on the news (source).
Tom: I might add that you should be very cautious about driving through water. You’re never completely sure what’s under the surface and even 6 inches of water can cause problems. If you stall when the exhaust is under water, the car won’t restart until it is towed or pushed out of the water. In Arizona they had what was called the “stupid motorist law”. If you drive into water and get in trouble, you have to pay for the cost of being rescued. The irony, of course, is that whenever there’s a flood, the standard image on the evening news is of cars driving through water. For more driving advice during floods, go to

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