In developed countries, why aren't houses too close to rivers built on stilts?

My best guess would be the mass production of housing types.

Actually, in many places in the world, houses in flood zones are built on above-ground “basements.” For some strange reason, that’s not done in the USA…

@incendiary_dan…I’m trying to get it.
@HungryGuy not just in the USA I never see them anywhere except in poorer countries. It sure is strange.

@flo – I think Dan has the reason. In rich countries like the USA, houses (or at least the individual structural elements) are products made in factories like any other product. But in poor countries, they’re built by hand in place brick by brick, and so can be built any way that’s needed.

Thank you both.

Because the Army Corps of Engineers made promises it can’t keep fully endorsed by insurance companies who said coast is clear you do not need flood insurance as you are not in a flood plain.

PLUS you then have these cheap attractive river front properties that with even the best available due diligence you won’t know the full scope of the threat of flooding until you are knee deep in it again thanks to tight lipped past owners and Realtors.

@Cruiser I mean when a person builds a brand new home, they can just build it on stilt, right?

Raised house adjacent to Ohio River About $200,000

@flo Of Course they can….it costs a lot more and those engineering decisions are driven by studies and report made available by the Army Corps of Engineers. They are under pressure to approve habitable waterfront property based on 100 year flood plain studies that are rendered obsolete by over building in the surrounding areas that virtually guarantee floods the experts said would never ever happen. So nobody spends the money.

In San Diego, the condos that were built in the river overflow area were required to have the parking spaces on the first floor, and the apartments above that.

Here along the Sacramento River, some build on mounds, and others put their main floor on the second level, with unused rooms below that.

Here’s one in Virginia Beach that I remember seeing. Several didn’t withstand the various hurricanes, such as Hurricane Floyd, which occurred while I was there in 1999. There are many like that on beaches throughout the U. S.

Thanks everyone.

Local zoning laws have a lot to do with it too. You can’t build a house on the river that blocks the view of the folks that own the houses behind you.

Here in Memphis, there is an affluent neighborhood called Harbor Town that is located on Mud Island. While it is really a peninsula and not an island, it sits on the edge of the mighty Mississippi River and another river that feeds into it.

One would think that these buildings would be built on stilts considering the risk of flooding, like we are currently experiencing.

If I had to take a wild guess, it would be that the risk of flooding is less than that of the tornadoes that pass through the area every year.

In many places, even in the US, houses are built on stilts. It’s not so new or novel. You can see those houses in the Florida Keys and Louisiana bayous without looking too hard.

But away from actual riverine living, people who normally live “on land” next to rivers also need daily transportation. And you can’t drive your car to a stilted garage. If you could, you still couldn’t drive out of the stilted garage into a deeply flooded roadway. So you’d still be stuck, stranded, cut off. That won’t work (people’s livelihoods being what they are in our economy) for the long stretches of time that floods can last, so it’s an option that people don’t want to pursue. Not practical, given the world we decided that we wanted – and set out to build.

Plus, as others have already described, the Army Corps of Engineers has had a two-fold mission: to improve river navigation by more and larger shippers, which means dredging deeper and wider – and straighter – channels, and maintaining optimum flow year-round, plus preventing floods of the riverbank communities with higher levees. Those missions are essentially at odds with each other.

Every time rivers are dredged and made straighter, to aid navigation, that speeds flood waters downstream. So flood stages that used to take longer to develop, giving downstreamers a better chance to get away (and more time – and places – for waters to dissipate into oxbows and sloughs), it makes the downstream effects faster and the water higher when it gets there.