Photo: Tobias Bauer/UNU
The seemingly never-ending rain at the end of May 2013 and in the first days of June has swollen rivers in southern and eastern Germany, as well as in the neighbouring Czech Republic and Poland. Eleven years after the centennial flood in 2002, the people of Dresden once again had to fight the rising waters of the Elbe river. With the record levels of 2002 being reached or surpassed, Dresden is among the affected towns that seem to have benefited from the lessons learned. Others were unfortunately not as prepared. The town of Grimma for example, had a half-finished wall, started in 2007 and then delayed, that could have prevented a second drenching in just over a decade. Instead, the town was among those that were flooded again.
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The City of Dresden and the Free State of Saxony have achieved considerable improvements in flood prevention and flood risk management since the centennial flood of 2002. But the flood of June 2013 once again highlights the risk of floods and other extreme climate-related events, and showcases the strengths and weaknesses of the implemented mitigation and adaptation measures.
Prof. Dr. Christian Bernhofer, Director of the Institute of Hydrology and Meteorology and Vice-Dean of the Faculty for Environmental Sciences at the Technische Universität Dresden (TUD), who is a member of the working group of UNU-FLORES and TUD, highlights the most important differences in managing the two floods in 2002 and 2013:
“Keeping in mind that the floods of 2002 and 2013 are different, as the Elbe flood will peak probably below 9 meters this year while in 2002, the peak of the flood was at 9.40 meters. Dresden was hit twice in 2002: first by the Weißeritz, a tributary to the Elbe, with already severe damage and then by the Elbe itself.””
“Altogether, there are three distinct improvements this year: First, the official communication regarding the flood has been better, quicker and more effective. Second, both new mobile and stationary protection walls have been used effectively to protect large parts of Dresden. Third, in the Weißeritz catchment there was less rain, there was more retention available and there were proper run-off pathways, avoiding severe consequences for Dresden. Nevertheless, other areas in Saxony or in Germany have been much more affected in 2013 than in 2002, highlighting that there is no complete protection, but a need to live with floods.”
Developing management options for extreme events such as floods and droughts, considering conditions of global change, is part of the mandate of the UNU Institute for Integrated Management of Material Fluxes and of Resources (UNU-FLORES). As one of the newest institutes of the UN University, founded in Dresden in December 2012, UNU-FLORES will, in close cooperation with colleagues from TU Dresden, other regional partners and its international research network, contribute to the further improvement of management strategies, emphasizing the need for an integrated approach.
The close linkage of water management with soil and land-use management as well as with waste management is already considered to some extent in current management strategies within Saxony. However, the current flood again highlights the need for integrated management strategies at the system (or watershed) level. Building or improving dams and water barriers is just one aspect and needs to be integrated in a suite of measures considering maintenance/rebuilding water-retention capacities, appropriate land-use management to prevent erosion, controlled flooding of certain areas, and others.
Prof. Reza Ardakanian, founding director of UNU-FLORES and an expert in water resources management, stresses the need for up-to-date water management:
“We see here in Dresden what good water management strategies can achieve, especially in areas prone to floodwater. But we also know that whatever is done, there is room for improvement. Here at UNU-FLORES, we work closely with our partners in Dresden and around the world to fine-tune and integrate such strategies into comprehensive environmental resources management strategies.”
A specific role of UNU-FLORES will be to transfer the locally acquired expertise, knowledge and successful management strategies to the international level, in particular adapting them to conditions in developing countries. Flood risk management as one aspect of climate change adaptation is an integral part of science and action for sustainable development. This notion has already been put forward in a keynote lecture of Prof. Ardakanian during the conference “Climate Change and Regional Adaption” (CCRR-2013), which was held in Dresden in late May.
The peak of the floodwaters on the river Elbe reached Dresden last Thursday. Residents and emergency crews worked around the clock to fight the floods, which spared the historic centre but engulfed wide areas of the Saxony capital.
Meanwhile, some 23,000 people were forced to leave their homes in the east German city of Magdeburg after the flood-swollen Elbe burst a dam. Further downstream, a levee at Fischbeck, west of Berlin, was breached, prompting officials to evacuate 10 villages in the area. Although floodwaters here were reported to be receding, parts of the country further north remain on high alert.
When the waters finally recede, the true extent of the damage caused by the centennial flood in Dresden will become visible. This will demonstrate which parts of the flood management and prevention have proven successful, where improvements are necessary, and what can be learned from Dresden for other flood-prone areas around the world.