DANA, which has flooded the province of Valencia with more than 200 deaths so far and has become Spain’s worst disaster this century, raises more questions than answers. Asked whether it was normal for it to take this long (currently more than eight days in the peninsula region), AEMET explained that this was something “exceptional”. But to the question of whether this will be a part of our lives from time to time, the answer seems to be yes. So there is one place that made the region impregnable to floods, far beyond what was predicted in the 70s: Vienna.

Global floods and exception. Before DANA in Valencia there were many residential areas recently affected by floods. Florida, Nigeria, India and other parts of Europe are some of them. Increase in the frequency and intensity of precipitation due to climate change and exceeding the capacity of the existing infrastructure.

However, one spot resisted harsh weather conditions. The city of Vienna stands out as an example of flood resilience, thanks to decades of planning and engineering. Not to go too far, Austria experienced serious flooding from Storm Boris a few weeks ago, but Vienna only suffered minimal damage to its metro system. The secret: a pioneering system that allows managing a flow equivalent to a “5,000-year flood.”

Inside the story. The protection of the city, which could not be spared from floods in September because it was on high land, was based on a political decision taken in the 1960s. donauinsel or Danube Island, a 21-kilometer artificial island in the Danube River. Completed in 1969, this artificial landmass forms a type of dam and control (and drainage) channel that directs water and protects the city from the large-scale floods that occurred in 1501 or 1954.

operation donauinsel. The new Danube fills when the floodgates open before a flood, allowing the Danube to handle high flows without overflowing. This system was truly put to the test in 2013, successfully demonstrating its effectiveness and significantly reducing the impact of flooding in the last storm.

Risks of suburban development and “Bodenversiegelung”. The Guardian reported a few weeks ago that recent rains have also revealed a “b” aspect: development risks in sensitive areas. In Tullnerfeld, west of Vienna, where a train station was built in 2012, many detached houses were built on flood-prone land.

Bodenversiegelung or “soil insulation”, which involves covering green areas with concrete or cement for urban development, further exacerbates the problem of flooding in surrounding areas. In other words, the magnificent system created around the city revealed the problem that spreads all over the world: Urbanization in risky areas increases the risk and cost of future floods.

Levee effect. Moreover, Vienna faces additional challenges due to this urbanization in former floodplain areas. Let’s imagine that these natural areas absorbed most of the water in previous floods, but are now occupied by houses and crops. This increases the risk of flooding, known as the “levee effect”: feeling protected, people settle near rivers, increasing the long-term risk and damage in the event of flooding.

Political challenge. No doubt, wherever it is, it’s just another problem to deal with. The Vienna experience also raises political questions. Moreover, the Donauinsel project initially faced opposition from the Austrian People’s Party (ÖVP), which argued that there were more urgent needs than looking into the future and possible climate changes.

Although this vision has changed greatly in local politics, there is still a view against it. The far right at the party and national level continues to oppose climate action measures; This reflects a global problem where a lack of political will sometimes prevents the implementation of necessary solutions.

Improving investment and forecasts. Another of the steps preferred by the government. Austria has increased its investment in flood measures, spending around 60 million euros a year. This strategy includes regular drills to establish mobile walls and an advanced forecasting system that allows for adequate preparation and a significant reduction in damage. In fact, accurate forecasts have helped the country predict the risk of flooding and plan evacuations in recent years.

Adapt to climate change. Today this seems clearer than ever, but as climate change intensifies storms in Europe, preparation is essential. Warmer seas, such as the Mediterranean, fuel these storms, causing more intense rainfall, as in Boris and now DANA in Spain. There is also another fact to consider: Disproportionate warming between the North Pole and the equator causes the amount of precipitation to shift northward. Conclusion? For example, devastating floods in Western Europe in 2021 have already killed more than 200 people, underlining the need to further improve disaster prevention.

The Vienna example therefore shows that building resilient infrastructure is important, although it is only the beginning in the fight against possible natural disasters. In 2023, a team of European scientists analyzing historic megafloods found that 95.5% could be predicted based on previous events in other comparable locations in Europe.

The planning and foresight shown by the European city can serve as a shuttle model for other cities to strengthen their resilience in the face of increasingly extreme and unpredictable climatic conditions.

Image | EU Civil Protection, Karl Gruber

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