Flooding is the most common of all natural disasters, and there is growing consensus that the frequency and number of people at risk from floods will increase. Global megatrends, including climate change, population growth and urbanisation profoundly exacerbate the frequency, intensity and impact of flooding. The OECD estimates that the number of people at risk will increase from 1.2 to 1.6 billion people between now and 2050. This will represent around 20% of the world population. In 2016, 23.5 million people were displaced because of weather-related disasters, of which the majority were associated with floods or storms. In between 1998 and 2017, floods accounted for close to one-quarter of global economic losses due to natural disasters.

Social, economic and environmental losses due to floods relate to both infrastructure and governance challenges. The increase of such losses in the recent past is not only due to more frequent and extreme floods, but also because of inadequate water and land use planning, as well as unsustainable infrastructure and technical solutions for managing floods. The report acknowledges that “hybrid” solutions, combining green and grey infrastructure measures are needed to address floods. Therefore, careful analyses should be conducted to evaluate the range of available options and design flood management schemes that combine natural, infrastructural and policy instruments in the most effective way.

Adaptation to flood risk requires a diversified approach from structural flood protection measures, early warning systems to nature-based solutions, social protection and risk financing instruments. The correct mix of measures varies from place to place, subject to levels of risk, funding, and political will, therefore, one size-fits-all approach cannot be applied. It will be increasingly important to evaluate choices with strengthened comprehensive, integrated and participatory multilevel governance approaches across foresight, mitigation, preparedness, response and recovery stages of flood management.

The report argues that improved flood governance greatly enhances the design, implementation and impact of flood-related policies and management measures. It stresses the importance of involving stakeholders in flood governance decision-making and increasing policy coordination, especially between water, land and climate change management. Four years after the adoption of the OECD Principles on Water Governance and in the framework of the implementation strategy developed under the OECD Water Governance Initiative, this report applies the 12 OECD Principles to analyse a compilation of 27 specific cases of flood management from around the world (one case focuses on transboundary strategic plan for flood management; nine cases concern national policy and/or programmes; five cases describe the governance arrangements for the day-to-day management of floods in specific locations; three cases present state/provincial flood management plans; three cases look at specific flood events; and six cases concern research projects, at the national or basin level). The report also builds on the guidance from the Recommendation of the 2014 OECD Council on the Governance of Critical Risks and its high relevance to floods.

The report suggests a Checklist with self-assessment questions to support flood management decision making. The Checklist intends to encourage stakeholder dialogue and peer learning, help understand better how flood governance systems are performing at local, basin and national level, and guide decisions at all levels. The Checklist primarily targets decision makers and practitioners directly responsible for flood management from the local to the national level, and is expected to be of relevance to risk managers and the broader range of water constituencies and stakeholders.

The report was approved by the Regional Development Policy Committee through written procedure on 4 June 2019, under the COTE CFE/RDPC/WGI(2019)3.

End of the section -- go next on the menu bar