As of June 6, the floods in Austria, Germany, Slovakia and the Czech Republic had killed at least 16 people, and damages were so severe that some said they could exceed the more than €21.1 billion cost of the historic 2002 floods in the region.
The Elbe River crested at 8.75 metres in Dresden and was expected to reach 11 metres in the northern Czech Republic, while in Passau, in southern Germany, the Danube crested at 12.89 metres on 4 June, the highest level in roughly 500 years. News footage showed how the torrents had broken through walls of sand bags, flooding cities, destroying property, and leaving thousands homeless and livelihoods ruined.
Floods have always been a risk for communities living alongside rivers, but recent years have brought several serious floods to Central Europe alone: Germany, the Czech Republic and Poland were hit in 2007, in 2009 and again in 2010.
Other countries have also seen major losses – including, last month, Norway, where rapid snowmelt and heavy rains combined to cause massive floods and mudslides in the central region of the country. It was the worst disaster since floods in 1995 that cost an estimated 1.8 billion NOK (€236 million).
Climate change may increase these risks, says SEI Research Fellow Åse Johannessen, who specializes in disaster risk reduction – but human choices are an even greater factor. “We have developed these river basins for centuries, and that has altered the water flows to increase flood risk,” she says.
Living with floods
Johannessen is one of several SEI researchers exploring ways to reduce flood disaster risks in urban areas – both in Europe, and in the developing world. For example, she has looked at how Kristianstad, Sweden’s most flood-exposed city, has begun to move away from trying to keep floodwaters out at all cost, to “living with floods”. The idea is to find ways to minimize the risk of catastrophic failures by allowing floods in some areas and adjusting land use to reduce exposure.
A major SEI project funded by the Swedish Civil Contingency Agency, WASH and Rescue, focuses on how floods affect cities’ critical water and sanitation infrastructure, creating significant health problems – for example, when sewage or floodwaters contaminate drinking-water supplies. Relatively simple technological solutions, such as site-raised sanitation systems, can address those risks.
“These floods are a clear reminder that we need to take urban resilience seriously in the coming years,” Johannessen says. “We know that these extreme weather events can and do occur, so we need to plan properly.” In many places, she adds, the solution is not going to be to build bigger and stronger embankments, “but to try to get to the bottom of the underlying risks”.
Many cities have lost wetlands and other natural buffers, for example, she says, so they may need to give up some productive land to restore them. And instead of creating a false sense of security behind massive barriers that could still break, with catastrophic results, they may need to accept some flooding and learn to deal with it.
Solutions at the river basin level
In addition to investments in sustainable and effective systems in urban areas, investments are also needed upstream in river basins to improve buffers and infiltration capacity. Upstream urbanization increases the hard surface cover, which alters the hydrology and geomorphology of runoff, causing channeling and more and faster runoff to downstream areas.
These changes are difficult and require political will, SEI researchers acknowledge, but the costs to communities in terms of lives lost, disease, disrupted livelihoods and destroyed property are powerful motivators. Some flood-risk reduction strategies may also have co-benefits, such as improved water quality; the recently completed Baltic COMPASS project explored how measures such as restoring wetlands could support both water quality and flood risk management.
The role of insurance
SEI Research Associate Gregor Vulturius, meanwhile, has examined the role of the insurance industry in making communities more resilient to extreme floods. Not only do insurance payouts help people recover from flood damage, he notes, but insurers can play a key role in identifying flood risks and disseminating knowledge. For example, the German Insurance Association (GDV) has launched a web- based tool that homeowners in Saxony can use to evaluate their properties’ flood exposure.
Insurers can also incentivize risk mitigation, Vulturius says – but it’s unclear how often they do. In Denmark, some discount insurance premiums in exchange for the installation of flood-proofing measures. But in Germany, many insurers simply stopped covering properties in the areas flooded in 2002, or increased premiums significantly.
“It is a great challenge for policy-makers to ensure that widespread protection against natural hazards prevails, independent of the availability and affordability of insurance coverage,” Vulturius says.