Managing the risks of flooding in Europe
“The timing of this workshop couldn’t be more important,” Elisabeth Lipiatou, head of unit for environment and climate change at DG-Research who chaired the event, told the Oct. 10 gathering of scientists in Brussels. “Floods are becoming more frequent, and our climate change models predict they will become more severe. We’ve got to put a maximum effort into forecasting, impact analysis and risk management,” she said.
As illustrated by the floods of summer 2005 and previous years, dramatic inundations are on the rise in Europe, with devastating impacts on human life, the economy and environment. The massive flooding of Germany and Poland in 2002, for example, was the worst since 1845 – and scientists predict this is only the beginning of the trend as climate change accelerates.
The workshop examined newly completed and on-going flood research projects supported by the EU’s Fifth and Sixth Framework Programmes. Participants also reviewed where future research should be heading.
The flood research challenges are daunting, to say the least. Europe has thousands of levees, dams and canal systems, some very old and built with rubble, whose structural integrity must be better analysed. Continental weather patterns are changing in subtle and still misunderstood ways due to climate change. Increasing urbanisation of the landscape means that floods now pick up and ‘churn’ manmade objects along their leading edge in deadly fashion, as Asia’s December 2004 tsunami so tragically demonstrated. Finally, vast quantities of hydrological and meteorological data await integration into harmonised modelling across the EU.
Nature will take its course, but will policy follow?
Flooding is on the rise not only due to climate change, however. The relentless canalisation of streams and waterways of the last 100 years has combined with urban exploitation of natural flood plains and marshlands to raise the stakes. Ground-absorption rates have declined, while run-off from melted snow and precipitation finds fewer and fewer natural channels. The result is increasing incidence of flash flooding at the local level and catastrophic-sized flooding regionally.
This trend has evoked a strong sense of realism within Europe’s flood research community about the merits of flood-risk management versus flood prevention.
“People in Europe generally believe they are well protected against severe flooding but there is no way to assure 100-percent protection against that,” Prof. M. Borga of Italy’s University of Padova told workshop participants. “Floods are getting more extreme, yet awareness among decision-makers and the broad public is not adequate,” said Borga, representative of the FP5 project MITCH, which oversaw a network of research institutes and public authorities regarding floods and other natural disasters.
Political awareness of the problem is growing in EU circles, however, and has caught the attention of the European Parliament. In a September 8 resolution on natural disasters, for instance, MEPs recommended the creation of a European observatory to track the effects of climate change – flooding, drought, desertification, etc. – and called on the Commission to increase research resources for flood prevention in order to produce as soon as possible “a coherent energy and transport policy in the area of risk prevention.”
The European Commission services are currently developing an EU floods directive, which will create obligations for Member States to manage risks of floods to people, property and environment. The idea is to implement concerted, coordinated action at river-basin level and in coastal zones to reduce the risks of floods.
EU flood research: the state of play so farBy no means has the Commission been sitting on its hands, though. Many flood research projects funded by the EU’s Fifth Framework Programme are completed or nearly so, while those financed by FP6 are fully underway. Moreover, DG Research aims to step up flood-risk research in the forthcoming Seventh programme as the latter’s budget is finalised, hopefully by the end of this year.
Workshop participants reviewed the results of a rich variety of FP5 projects, ranging from development of a prototype pan-European flood forecasting system, known as EFFS, to the EURAINSAT project. The latter’s satellite observation techniques studied the physics of clouds to integrate them into precipitation-forecasting models.
One particularly intriguing FP5 project, known as IMPACT, used ground-penetrating radar to analyse structural weaknesses in centuries-old dams and levees, and how these structures crumble once they’ve been breached.
“We’re learning that a lot of sediment is carried by the front wave of a breached structure, which slows down its propagation,” said IMPACT project representative P. Samuels of the UK-based hydraulics research and consulting firm, HR Wallingford. “But it also causes more destruction due to its density. There’s a lot of new R&D needed to refine sediment modelling,” he added.
The workshop also examined on-going flood research and the FP6 project known as FLOODsite. As an Integrated Project, it is the EU’s largest single flood research effort so far, with a total budget of €14 million of which €10 million is EU money. Also coordinated by HR Wallingford, the FLOODsite comprises a team of 36 institutes that are investigating four key areas of flood impact:
- the movement of sediment;
- the mechanics of embankment breaching;
- simulation of catastrophic inundation of valleys and urban areas;
- integrated use of geophysical techniques to assess flood defence embankments.
Noting that Europe “now leads the world in flood research,” Samuels said the project’s overall goal is to create an integrated approach for reducing uncertainty in predicting extreme flood conditions across the EU.
What lies ahead?
Workshop participants floated a number of ideas for future flood research in the EU’s next Framework Programme. These clustered around two themes: how to improve research tools and databases for predicting and managing floods, and those related to ‘pressures on the environment’, which refers to the broader causal relationship between climate change and flooding.
Though Europe has made good progress under FP5 and FP6 in analysing historical and real-time information on floods, participants said more work is needed such as development of European databases on extreme flooding tied to other natural hazards and their human, social and environmental impacts, for example. They identified many potential priorities for FP7, including the study of:
- sediment/debris generation and propagation in extreme floods;
- probabilistic real-time risk forecasting of multi-hazard events;
- feasible extreme flood-management options;
- non-intrusive technologies to measure infrastructure defences against floods;
- the performance of storm sewerage systems under intense rainfall or wave over-topping;
- the fate of flood-borne pollutants and pathogens in urban settings.
As for future priorities related to ‘pressures on the environment’, these ranged from modelling issues to research supporting the notion that interactions between the atmosphere, land surface, ice and oceans must be approached and studied in an integrated way.
“There is a wealth of meteorological data available but it is not being fully exploited, particularly regarding the physics and behaviour of clouds,” said workshop participant and coordinator of the EURAINSAT project, V. Levizzani, who works at the Institute of Atmospheric Sciences and Climate of Italy’s National Research Council. “I would argue for more investigation of cloud modelling capabilities, including ice cloud content, and more research into land-atmospheric interactions in climate models, especially regarding the role of vegetation covers,” he said.
Indeed, developing accurate modelling techniques will be crucial, said Z. Kundzewicz, a researcher with Poland’s Academy of Sciences at Poznan and representative of the FP5 Project known as MICE (Modelling the Impact of Climate Extremes).
“Higher and more intense precipitation has already been observed in many areas of Europe and this trend is expected to strengthen in the future,” he told the workshop. MICE’s study of the projected climate of 2070-2099 reveals a reduction of intense rainfall over southern Europe and an increase over the continent’s northern region, for example.
“Even though climate models are bound with high uncertainty, one needs to frame the possible futures,” Kundzewicz observed.
Other climate-related research priorities identified by participants included:
- new databases to integrate information on past events and Earth observation data;
- the direct impact of greenhouse gas concentrations on hydrological extreme events;
- the mechanisms that trigger extreme events;
- new models to study uncertainty and predict flood impact.