Floodplain management: reducing flood risks and restoring healthy ecosystems

The floodplain is the area next to a river bed which is more or less frequently covered with water in times of high water discharges from adjacent rivers. Wetland is one type of floodplain. By retaining water, floodplains can buffer the effects of heavy rainfall and in this way protect economic activities and communities further downstream from flood damage. However, many former natural floodplains are under increased pressure from urban sprawl, infrastructure developments and agriculture. In Europe, up to 90% of floodplains have been lost during the past centuries or are no longer able to serve as functioning natural ecosystems providing flood risk reduction and habitats favouring a high biodiversity.

The EEA report ‘Flood risks and environmental vulnerability — Exploring the synergies between floodplain restoration, water policies and thematic policies’ draws upon information published in the European flood impact database which covers floods reported between 1980 and 2010. The report highlights the benefits of an integrated approach to flood risk management and argues that a coordinated implementation of EU legislation, such as the Water Framework Directive (WFD), the Birds and Habitats Directives and the Floods Directive through coherent measures and actions, would enhance the effectiveness of the policies.

The restoration of healthy ecosystems, for example through the Natura 2000 networks, is often a very effective way of preventing and mitigating floods. Even when 'hard' flood defences, such as dykes, are necessary to protect communities, those measures should be complemented with long-term nature-based solutions such as floodplain restoration. By 'greening the grey' and making a network of green infrastructures, the necessary protection levels can be combined with a minimum loss of habitats and a good preservation of ecosystem services.

Other key findings

• Between 1980 and 2010, 37 European countries registered 3,563 floods in total. The highest number of floods was reported for 2010 (321 floods), when 27 countries were affected. This number is associated with the 'Central European floods', which occurred across several Central European countries during May and June 2010.

• Based on reporting from nine countries, the report maps the share of population living in floodplain areas. Among those countries, Italy has the largest population living in flood-prone areas (6.7 million people, 11% of the population) whereas Hungary has the highest relative share of people living in such areas (1.8 million, 18% of the population).

• Annual flood losses can be expected to increase fivefold by 2050 and up to 17‑fold by 2080. The major share of this increase (70–90%) is estimated to be attributable to socio‑economic development as the economic value of the assets in floodplains increases, and the remainder (10–30%) to climate change.

• Future extreme floods are likely to be the cost drivers for the adaptation of infrastructure. Ecosystem-based adaptation, nature-based solutions and green infrastructure are, in many cases, key in ensuring a cost-effective approach to an uncertain scenario by delaying or avoiding lock-ins to classic infrastructure-building water management. The report also notes that although strategies for flood risk management require measures that are specific to the local circumstances, using a river basin approach avoids passing on negative consequences further downstream.