Learning to Go With the Flow

Just 11 years after the "flood of the century" devastated parts of Upper and Lower Austria, Austrians once again felt the full destructive impact of a river system bloated to record levels. At the beginning of June at Korneuburg on Vienna’s western edge, the Danube reached a height of 7.93m with 10,600 cubic metres flowing per second – faster even than in 2002.

All along the great river and its many tributaries, Austrian fire brigades and teams of volunteers raced against time to fortify the banks with sandbags.

In Upper Austria 200 houses were flooded in the town of Schärding. Five hundred people were evacuated. Schools were closed. When the waters finally receded, riverside communities were left contemplating metre-thick slurries of mud, inundated cellars and ruined irreplaceable mementos.

Many homes near the rivers had been unable to secure insurance against flooding, and there were tears of desperation in front of running television cameras. The economics research group EcoAustria estimated that the damage would amount to €2.2 billion.

A flood is, of course, a natural disaster but the catastrophe, says Ulrich Eichelmann of the conservation group Riverwatch, was also partly man-made.

"We have to give more space to the rivers," he says, complaining that Austria’s rivers have become "straitjacketed". Engineering projects to control them have meant that when intensive rainfall hits, their flow is more destructive than ever in history. "The flood wave is becoming faster and faster. If you have a home in the way, you have less time to prepare. In Austria the flood wave is three times faster than it was in the 1950s."

This is partly because the riverine forests that used to line most European waterways have been heavily depleted. According to Eichelmann, only 4 per cent of Austria’s rivers are fully intact. Elsewhere, banks have been reinforced with concrete and boulders, preventing the natural meandering. The Danube has lost 90 per cent of its original flood plains.

On the one hand, this has created farmland, industry and housing in areas once prone to seasonal flooding and has also meant "green" energy for Austria in the form of 5,000 hydro-electric projects that harness the power of the current. But for Eichelmann the extent of the technical engineering has been folly:

"You cannot totally control the rivers. It’s like putting a human being in a corset so tight that they can’t breathe. At one point they will start doing crazy things."

When the rains come, a "corseted river" can’t spread out sideways. Instead, it burrows down, creating a faster flow, which can prove devastating when downfalls are heavy.

But where the floodplains have been left intact, the damage has been limited. The wooded wetlands of the Lobau near Hainburg on Vienna’s eastern side, for example, absorb water during times of heavy rain and, this June, played an important role in slowing the flood wave before it reached Slovakia’s capital, Bratislava. In drier times, these wetlands provide a haven for biodiversity and a popular leisure oasis for hikers, cyclists and canoeists while replenishing ground water storage, thus guaranteeing the quality of drinking water.

Eichelmann describes this as a "win-win" situation and would like to see more land in vulnerable areas returned to nature. But is that realistic? "It’s a matter of political will," he says. "If the government needs land to build a new motorway they manage to purchase it."

Not all engineering projects to control the river are bad. The Neue Donau, an artificial canal constructed in the 1970s, which created as a side effect the popular recreation centre on the Donau Insel, has proved a highly successful project. Despite the record flow of the Danube, Austria’s capital, historically plagued by "natural" floods, came through once again largely unscathed. The only significant damage was to the entertainment centres of the Copa Cagrana. "We have to have technical flood control in the villages and urban areas," concedes Eichelmann, "but elsewhere we have to allow the river to reclaim part of the countryside."

Eichelmann is backed up by the World Wide Fund for Nature (WWF) who, in a recent study, have estimated that 84,000 hectares of land near rivers should be restored to nature.

"For every Euro spent on technical measures to protect settlements from floods, we need to spend a Euro on freeing the rivers from their corsets," says the conservation group’s river expert Christoph Walder. He’s calling on a new federal action plan that promotes ecological flood defences. "If the rivers could flow more freely, we could dramatically reduce the potential for damage of the next flood."

Eichelmann is pessimistic about the prospects of an official rethink. In the past 60 years, 4,000 square kilometres of natural flood plains were taken away from the rivers, an area the size of Burgenland. After the shock of 2002, which caused over €4 billion of damage, the conservationists called for this process to be reversed, but instead a further 400 square kilometres of natural flood plains were removed.

Now, as climate change heralds the potential of ever more cases of "extreme weather", the question is whether Austria’s politicians, still counting the costs of the recent flooding, can afford to ignore the advice of the conservationists any longer.