Natural floodplains are formed where water spreads silt and mud in river valleys.
Being flat, fertile, picturesque, and usually supplied with surface and underground water, they attract farms, orchards, and gardens.
These are inevitably followed by roads, houses, and businesses.
Despite all the planners and their rules, the pressure of people plus a bit of corruption has always resulted in populations clustering on fertile floodplains and deltas beside scenic rivers.
There is no point trying to stop or reverse this tide of history but those who choose to build on floodplains must bear the costs of the occasional flood.
Community groups will always help those stricken by floods but taxpayers and insurers should not be forced to subsidize the insurance and damage costs for those who choose to live in risky places – their choice, their risk, their cost.
Naturally, insurance for the flood-prone property will be expensive or not available – a clear message for those with ears to hear.
More cautious people build on the hills and leave the floodplains for floods, farms, trees, market gardens, and grass. Rational town planning would require sellers and developers to provide accurate flood maps to buyers, and councils should paint flood levels on power poles.
There are few risk-free home sites. Those who build in thick bush or neglect cool-season burn-offs will inevitably suffer from bushfires; those who build on floodplains will be flooded; those who locate near fault zones will be shaken by earthquakes; those who build near the sea risk cyclones, giant waves, and tsunamis; even those who farm the rich volcanic soil near “dormant” volcanoes risk burial under ash and lava.
The old railway engineers quickly learned to build above most flood levels wherever possible. So a useful rule is: don’t build essential infrastructure below the railway lines.
If you choose to locate on a floodplain, be prepared to pay higher insurance costs. And if you build your house there, build it on stilts.
Rather than wasting billions on futile efforts to change the global climate, governments should spend those billions on flood-proofing their railways, bridges, roads, and electricity supply, and building more dams and weirs to conserve water and moderate floods.
Viv Forbes is a geologist who has studied landforms and lived on several farms near creeks and rivers that flood. He and his wife now live on a hill watching the floods draining from the plains and moving towards Ipswich and Brisbane, both river cities.
Real estate developers are the snake-oil salesmen of the modern era, they wait a decade or so after floods to let the news cycle settle and rebuild on those plains. I observed this in the 1993 flood that inundated massive parts of Midwest USA; I lived in Missouri at the time and we moved to Colorado after the waters subsided. I drove across miles and miles of grey wasteland that I thought would never be used again. About 15 years later I returned to visit the region and already new homes and commercial centers were being built on what was once termed “Gumbo Flats”, renamed to Chesterfield Valley. Today, the development is 3x the size and just waiting for the next 500-year flood event to inundate it.
Back in the winter of 1964/65 our area here in Northern California was flooded it starting with a cold front coming from the Arctic and dumping a lot of snow on his a warm front(Pineapple express)turned the Snow into Rain melted off the snow and we were flooded and deemed a Disaster Area our area in Scott Valley in Siskiyou County all the Bridges were washing out and we were isolated for few weeks they brought in stuff by Helicoptor
I refuse to live in a flood zone. Many do live in such zones here in Australia.
Apparently, it is hard to know which areas flood and which don’t.
If only there was a simple way to determine that, like water only running downhill…
Seriously, I know of a house that had serious flood defences built around it. The house was put on the market but did not sell until the defences were removed. Clearly, it was too confronting to potential buyers to have to consider that a house beside a river could ever flood.
What I saw as a feature was determined by the housing market to be a flaw. To be fair, the new owners shall be fine.
For a while…
In Roseburg Oregon in the 1950’s there was an elevation that was considered safe from flooding. My relatives didn’t pay attention to that. What they did use was the elevation of trees that had been deposited along the river bank and make sure they built at a higher level. One year the “safe” elevation was flooded but my relatives were unaffected.
Sensible people. That’s becoming something of a rare commodity these days.