Flooding – does it really have to be such a big problem?
Throughout history villages, towns, military encampments (and the cities and metropolises of today they have turned into) were – without fail – built near, around, on or technically under (igloo anyone?) water. This is not a coincidence. The human race has always gravitated towards this precious liquid – building our settlements near a well, spring, stream, river, lake or the majestic seas, always staying close to the element our bodies are mostly made of – and the element we need for pretty much everything we do.
The dawn of civilisation famously occurred in ancient Mesopotamia (its name meaning “between two rivers” in Greek), a region between the great Tigris and Euphrates rivers in what we now call the Middle East. These lands – made fertile by the annual flooding that deposited tons of nutrient-rich silt from the rivers onto the surrounding lands – provided the inhabitants with all they needed for a comfortable life, giving them the time and freedom to create a civilization. And create they did.
The wheel was invented there, animals were domesticated for the first time in history, the origins of agriculture were developed. We can thank the eastern plains for wine and beer, first developed by the ancient Mesopotamians. These people believed that water was the “first principle”, that from which all else flowed. How right they were.
Even today, the greatest cities on Earth stand by the water. Ancient Egypt evolved thanks to the power of the Nile. Paris was built around the Seine, the city originating on two islets in the river. During the recent fire that ravaged the church, the Notre Dame cathedral was saved with water pumped from the river. Vienna, Bratislava, Budapest, Belgrade – all metropolises on the mighty Danube. London sits atop the Thames. New York at the mouth of the Hudson river, right by the sea. Rome on the Tiber. Frankfurt on the Main. Many great cities stand proudly on the shores of the world´s seas. Barcelona by the Mediterranean, Sydney by the Pacific, Lisbon by the Atlantic Ocean – the list is long.
Whether or not we are aware of it, our lives revolve around water. Every single one of us needs it to survive. We need to drink it, irrigate our crops with it, cook with it, give it to our livestock, make energy out of it or with its help, swim in it, sail on it, fish in it, relax near it, transport goods over it… All the while – despite its importance – most of us treat it as an infinite, readily available and harmless resource. As with most of Mother Nature´s gifts, some of us don’t even realise how destructive it can be.
One of the more dangerous forms water can take, when it gets somewhere it shouldn’t be, is flooding. Massive amounts of water cover land that is normally dry, having escaped or been released from its normal confines – be it a lake, river, creek or the sea (natural causes); a reservoir, canal or dam (man-made). Floods are some of the globally most common and dangerous hazards. For example, out of all the natural disasters that plague the United States, floods cause by far the most death and destruction.
There is no question that extreme weather has become a reality. Just over the past decade, water has flooded large parts of Germany, Austria, France, Canada and the United States –to name but a few countries. Floods happen when it rains excessively in land areas, when dams or levees rupture, when snow or ice melt rapidly; even when beavers position their dams in an inopportune place. In coastal regions, the sea can surge inland under the influence of a large storm or a tsunami.
The ABC of floods
Many factors (including, but not limited to the melting of glaciers and sea ice) are contributing to a rise in sea levels, putting more and more places – such as the iconic city of Venice – at risk of flooding. The unique capital of Northern Italy’s Veneto region is a place that is already experiencing serious flooding four times a year.
Floods can occur due to many reasons, be it heavy rain or snowstorms, unfortunate topography, tidal influences, melting glaciers or rising sea levels. There are many different types of floods. Flash floods occur after heavy rainfall, the rapid melting of snow and ice or when dams burst. Large amounts of water sweep the land in a matter of minutes, wreaking havoc to all in its path. When it rains more heavily than usual, cities and villages are not able to deal with the increased amount of water if there are no preventative measures in place.
Part what causes exacerbated rainfall is climate change. It is increasing the risk of flooding by causing extreme weather events and the rise of sea levels. The climatic change brings about a higher mean air temperature, which causes the formation of massive, intense hurricanes. Hurricanes are huge storms that can last for days, move slowly and deposit incredible amounts of rain onto the Earth, cause massive floods and obliterate entire towns. A recent and quite famous example is Katrina, the costliest storm in U.S. history – a fierce, Category 5 hurricane that decimated and massively flooded the city of New Orleans and the coastal region of the state of Louisiana, causing many deaths and millions of dollars in damages, as well as halving the city’s population.
Atmospheric rivers are powerful rainstorms that form over large bodies of water, such as the Pacific Ocean. Water evaporates from the warm ocean surface and fizzes into the atmosphere. The wet air, stacked with vapor and cloud droplets then travels towards land, meandering through the atmosphere – reminiscent of a river hovering in the sky – and discharges its water load upon impact, in the form of rain or snow. Atmospheric rivers can occur on all 7 continents and of course – they cause flooding. So, a warmer mean air temperature means the air will be wetter. It will become a very suitable host environment for the formation of atmospheric rivers.
When the flood ends and the water recedes, flooded areas are left devastated – covered in mud, sand, clay or any other material the briskly flowing water has deposited. Debris, pesticides, overflowing sewers, mould – water-soaked landscapes and structures often become health hazards and may lead to the outbreak of diseases like typhoid, cholera and hepatitis A. This all sounds quite bad, as if massive floods are inevitable and life around water is mostly hopeless. But actually, there is much that can be done to control or even prevent flooding. We must only look at the problem from a different perspective, as the Dutch have done for decades.
Delta Works – A very successful experiment
The Dutch are the world´s go-to water management experts. 26% percent of their country is situated below sea level. To make matters even more complicated, a further 50% percent of the territory is less than 1 metre above sea level. The terrain on which today’s Holland lies was a true delta 2000 years ago, a place fully dominated by water, filled with wetlands and rivers – not to mention the huge part of the country that was subsequently reclaimed from the sea, thus enlarging the territory.
For centuries, the Netherlands has been dealing with flooding and elevated water levels by developing innovative water management techniques. Windmills were an early technological advancement that the Dutch used to drain swampy areas by pumping out water with the help of wind energy. The 20th century was a turning point for Dutch water management. In 1953 the North Sea, agitated by a heavy storm and aided by a high spring tide, flooded an enormous land area – striking the Netherlands, Belgium, England and Scotland. The water rose 5.6 meters above the mean sea level. The existing maritime defences were overwhelmed, and massive flooding ensued. Realising that such a “once-in-a-century” storm will certainly happen again, the Dutch set about constructing a complex and impressive defense system.
The Delta Works project consists of a series of dams, dykes, levees and storm surge barriers in South Holland and Zeeland. It purposefully considerably shortened the Dutch coastline, greatly reducing the number of dikes that would have had to be raised to protect the land. The American Society of Civil Engineers has even declared it one of the Seven Wonders of the Modern World, hailing this system as one of the greatest civil engineering achievements of the 20th century. The Delta Plan is a nationwide programme that sees many people work together in harmony – the national government, provincial authorities, principal authorities and water boards all collaborate to maintain this system of defence from the North Sea.
Dutch dams – Unspeakable feats of hydraulic engineering
An impressive modern example of Dutch water engineering is the Maeslantkering, a storm surge barrier on the Nieuwe Waterweg in the south of the country – and one of the largest moving structures in the world. This impressive machine is meant to protect the port city of Rotterdam from being flooded by the waters of the North Sea, as most of the city lies up to 6 meters below sea level. Two large arms, each as long as the Eiffel Tower is tall, are positioned on each side of the waterway. They can close off the canal by floating into position and then being submerged, filled with water and turned into a massive barrier that sinks due to the additional weight. After the external water levels return to normal, the water is pumped out of the pontoons and the barrier can be opened. Everything is computer-controlled and makes a prime example of the Dutch mastery of hydraulic engineering. It is a giant, wonderful, impressive technological marvel, a true feat of the mind.
Another barrier that is hard to wrap the mind around is the nine-kilometer-long Oosterscheldekering, a special dam that connects several Zeeland islands. It is an internationally renowned flood protection project, as the dam is usually open – not something most dams are known for. If the dam were closed, the water behind it would lose its salinity, resulting in the disappearance of salt-water fish and marine plants. To avoid this problem, the barrier can instead be closed in the event of an emergency. The moveable part of the dam is almost 3 kilometres long, featuring three sluice gate openings.
This dam stands on 65 concrete pillars. It features 42 steel doors, each of them 42 meters wide. The life-saving barrier was designed to last more than 200 hundred years and was also declared one of the Seven Wonders of the Modern World. It is operated manually, with an electronic security system acting as a backup. Before the doors can be shut, the water must rise to at least 2 meters above regular sea level. The dam has been fully closed 27 times since its inauguration in 1986, the last time being in January 2018. It protects hundreds of thousands of people against high water that could submerge the land.
The Dutch people really know how to handle water, even making Dutchman Henk Ovink the world’s first Special Envoy for International Water Affairs. This position enables Mr. Ovink to share Dutch water management expertise with the world. He now works as an advisor to many governments, helping the US government rebuild the New York and New Jersey region after it was decimated by a hurricane a few years ago. We could all learn a thing or two from Holland, a country so cool, it managed to claim land back from the sea. Even Poseidon would be impressed.