May 13, 2011
How To Adjust To A Flood Plain?
Looking at photos of Mississippi River flooding submerging some mobile homes triggered a thought: What would it cost to build a floatable mobile home? Note that unlike a house boat it would not need to be water-tight at all time.s It could be designed for easy to conversion into something floatable. It could sit on sealed barrels that are anchored to it. Or a set of inflatable cushions could be brought in and inflated under it.
The potential costs of a really big flood triggered these thoughts. A Christian Science Monitor piece about past great floods mentions that a flood as large and lasting as the 1927 Mississippi River flood would cost $160 billion.
A Risk Management Solutions study, published on the 80th anniversary of the flood, estimated that a repeat of the same flood would cause up to $160 billion in damages in modern times.
I wasn't aware that the potential for financial damage is that large. So, short of convincing people to move, what could be done to cut the damage caused by floods? Floatable assets seems an obvious option. Mobile homes are in theory mobile. But it takes time and a truck to tow them to higher ground. Is it practical to try to clear all the mobile homes out of a flood plain when rising waters threaten? Or can floating in place be made to work?
Another idea: Mobile home elevators to lift them up onto steel beams. Imagine all the mobile homes lifted up on steel or aluminum stilts when a flood looks likely. Sound practical?
Update: Another idea: Build dykes just around individual houses. Great pictures at the link.
Anchoring would be an engineering challenge. The Mississippi current is deceptively fast, app. 7 MPH. Floatable buildings would be less tornado resistant.
Personally, I wouldn't live within a 50-year flood plain. For the 100-year range, I think the answer is inexpensive houses, and I'd think you could build 2, 3, for the price of a flood-proof home.
For farms and such the house is not the most valuable stuff. Tractor, implements and non float-able structures, plus you have you have stuff that can't be moved of lifted at all; Water well, sewer, roads all of which will take damage in a flood.
Flood plains flood. It's their nature. That is why they are called flood plains in the first place. You deal with it by land use policy, don't use the land for anything that flooding would be disastrous. Build houses, towns on higher ground. Use the plains for farmland, parks, range. Owing to the sheer size of the plains, you may have to compromise by creating artificial high ground for some farmsteads, towns etc. So they'd turn into islands during the flood, on which you just wait out the flood.
LarryD is correct. I would add that the Mississippi flood plain is valuable agricultural land, but it is not long term worthwhile to try to keep it from flooding. Instead of spending efforts trying to control the Mississippi, we should invest in a canal system to take barges from Cape Girardeau MO down the high bank side of the river (the east) to about Jackson and thence east to Mobile Bay. The river should be allowed to assume its natural course down the basin of the Atchafalaya.
Interesting comments. Big homes? Fuggedaboudit. Smaller homes could be made like houseboats, with a very strong system at the corners to allow flotation but not drifting. Some cost problems would be involved, but "doable"? Yes.
Interesting home construction possibilities. Build it offsite, truck it in, plunk it down on a pad/foundation with water/sewer/power/cable connections as a motor home, anchor it, live. Flood coming? Disconnect, go self-contained.
Alternatively, Jim Walter Homes used to have a design for prefab beach homes involving parking underneath, living on what looked from the outside like a second story. Compact use of land, stay dry up above. JWH is gone now, of course.
Combine the two concepts, you can have a bigger home. Might even look sort of "normal" if artfully done.
I have always had what I thought was an excellent idea regarding flood plains: don't freaking live in them if you can't afford to rebuild. It is utterly beyond me that people think it's a good idea to keep important possessions below even the the 100 year flood plain line. I just don't understand. Really, I don't.
It's as if they aren't even considering the risk/reward tradeoff.
A number of houses in Australia were lifted off their stumps and floated away during our recent floods. Being inside one was extremely dangerous. It should be cheaper and safter to build houses on high stumps or stilts than to make them float. Mind you, some of our stumped and stilted houses had a distinct lean to them after the flood. Making the ground higher before building on it is also an option.
Agreed on the great pictures. Very cool. Thanks for that.
These pictures point toward a different adaptation that I hadn't thought of: Build up permanent small dykes around valuable buildings. Say you are going to farm low lying land. Could be worth it even with occasional floods if the soil is rich enough. So build a farm house and then build a dyke around it.
Large fractions of the human population have assorted cognitive defects that cause them to ignore occasional dangers, miscalculate odds, and make really big mistakes about their impulses and what to do about them.