Learning from disaster

Seven years ago Germans watched in disbelief when floodwaters, almost within hours, washed away streets and whole villages in the eastern state of Saxony; the result of heavy rainfalls on a magnitude not seen in generations.

Up until that summer, Germans were sure that natural disasters only happened in distant parts of the globe. But that attitude changed as thousands of people in Saxony, neighboring parts of Poland and the Czech Republic were struck by disaster themselves, and lost everything.

When the first shock had subsided, the big clean-up started. Lots of money was poured not only into reconstruction, but also into flood protection measures, including the building of many new levees. And it did not stop there. In 2007 the European Union passed a new set of guidelines that member states are expected to implement soon.

Step one, according to Volker Meyer from the Helmholtz Center for Environmental Research in Leipzig, is to draw up maps depicting the local risk of flooding. Only on that basis can they then work out what measures to take to reduce that risk.

Evaluating risk is a challenge

Brussels expects this risk appraisal to be complete by 2011. Risk-maps already exist for some areas such as Leipzig. The city is laced with many small rivers and streams, only few of which are still in their original state.

Time and again the city has reclaimed land from riverbeds in order to have enough space for all of its half million inhabitants - a practice that greatly contributes to the risk of flooding. It is man-made risks like these that Volker Meyer and his colleague Dagmar Haase seek to minimize.

The two researchers have run computer-simulations of heavy flooding as it might occur every 50, 100, 200 or possibly only every 500 years. The results are several maps with various numbers of red spots depicting potential economic risks, i.e. the cost of reconstruction in the wake of a flood in a given area.

However, that alone cannot be enough, insists Meyer, who had spoken to those affected by the 2002 floods. "Many of them said that the damage to their homes was not even the worst part of their experience. It was the stress of the whole situation that really got to them."

Researchers seek input from affected groups

But is it possible to measure stress only in financial terms? This is the difficult part of assessing risk and disaster impact admitted Dagmar Haase. For the moment her and Meyer's recommendations only cover economic data.

"Money is easily counted, negotiated, understood. But when Leipzig city's forest ranger tells me that local eco-systems - forests, meadows etc. - need time to recover, then this is hard to express in measurable criteria", said Haase, "and so people don't account for it and in fact it gets forgotten."

The researchers in Leipzig want to focus on precisely these important aspects that are so difficult to capture. Their goal is to include in their assessment many groups of people in various places, who could potentially be affected by new floods in all sorts of different ways: Hospitals and local businesses, children and pensioners, culture and nature are all represented by different colors in the simulations.

To implement this in the real-world, the researchers seek input from each of those potentially affected groups. "We ask them 'What do you actually consider important? What type of risk concerns you most?' ", explained Meyer. "This then helps us to weigh and rank different types of risk."

Disasters help research

EU-member states have until 2013 to produce high water risk maps. These are supposed to contain information about the number of people potentially affected by flooding as well as potential environmental damage.

Two years later management-plans are expected to be complete to provide concrete measures to reduce risks such as preventing the construction if new housing in areas prone to flooding. All this may also help to keep alive the memory of events in 2002 - not only for scientists like Meyer and Haase.

"I would never say that flooding is necessary to establish or further research", said Haase. "But it is true that events like these help us to understand better that we do live in a natural environment, which at any time is capable of turning upside down all man-made systems."

Author: Christian Forberg (rri)

Editor: Mark Mattox