Editor’s pickConsidered a fairly common occurrence, flooding is one of the world’s most dangerous natural disasters

28-08-2017

The Grand Canyon in Arizona, United States (U.S.), is one of the seven natural wonders of the world. Yet it is also a testimony to the destruction and erosive power of water. Image credit: National Park Foundation

Rare is the place where one need not worry about flooding – after all, any place touched by rain is a vulnerable area, though rainfall is hardly the only driving factor behind floods, according to National Geographic.

Floods are when there is an oversupply of water that covers land that is usually dry. While this can happen in numerous ways, the most common incident is when streams, lakes, or rivers swell and overflow their banks. And factors behind this natural hazard can range from a damaged dam, excessive rainfall, or perhaps even ice melting too rapidly due to rising global temperatures, leading to the water spreading over the surrounding land, known as a floodplain. On the other hand, when a coastal area floods due to a squall or tsunami, when the sea surges onto land, it is coastal flooding.

While the majority of floods happen slowly, taking hours or perhaps even days to develop, and residents of the area have time to brace themselves or evacuate, flash floods can be quickly produced, almost instantly turning a bubbling creak into an extremely dangerous wall of water, clearing everything standing in its way.

And according to the World Health Organisation (WHO), drowning is the leading cause of deaths in both coastal flooding and flash floods.

But the truth is that moving water is a destructive force with almost endless power. Erosion, after all, is due to moving water, and while it has given us magnificent wonders such as the Grand Canyon in Arizona, United States (U.S.), one of the seven natural wonders of the world, structures not equipped to hold up against that strength pose no match. Entire bridges, cars, trees, and even houses have been known to be uprooted by that fearsome power and carried off, to be unceremoniously dumped further down.

Even in the U.S., where flood mitigation and prediction is one of the most advanced in the world, floods still manage to wreck an estimated US$6 billion worth of damage and kill around 140 people annually. In China, over the past century, millions have died in the Yellow River valley, where some of the worst floods in the world has happened.

According to the Organisation for Economic Cooperation and Development, coastal flooding by itself is responsible for approximately US$3 trillion in damages around the world.

And when the floodwaters finally recede and residents can return to pick up the pieces, areas that had been affected by the floods are regularly buried in mud and silt which may contain hazardous materials that range from untreated sewage to sharp debris, among others. Because everything is soaked in water, dangerous mould and algae can quickly engulf entire structures. Waterborne diseases such as cholera and typhoid may flare up. All of this before considering that those affected by the floods may be cut off from power, electricity, and clean potable water.

However, flooding has been taking place for millions of years. Areas such as the Nile River valley in Egypt and the Tigris-Euphrates in ancient Mesopotamia were historically rich due to their agriculture and trade for millennia due to the floods leaving nutritious silt deposits behind them – the floods and their accompanying rituals were even woven into their ancient religions.

But in the present time, wide-ranging efforts are being made to mitigate, and possibly even redirect floods, have culminated in some of the most visionary engineering efforts ever before seen, such as the immense dams and dikes the Netherlands boasts. Additionally, cutting-edge computer modelling allows disaster authorities to forecast when and where floods will occur, and their level of severity, all with amazing accuracy.

But flooding, as is with all natural disasters, cannot be stopped, but only prepared for.

 

Sources: National Geographic, Organisation for Economic Cooperation and Development, World Health Organisation