Flood risk is expected to increase in the future. Sea-level rise, more frequent peaks in river discharges and extreme weather events pose a challenge to decision makers dealing with flood risk management. It has been increasingly acknowledged in recent years that to enable integrated flood risk management and increase global flood resilience, future collaboration between different research disciplines and practitioners is important, as well as the development of supporting methodologies.
Dealing with flood risk and uncertainty in sea-level rise
Step-by-step investments in flood risk management and starting with low-regret measures are ways to remain flexible while keeping options open for the future when conditions are likely to change and require adjustment. However, the integration of flood safety with economic interests and other challenges is not straightforward (Storyline: Spatial adaptation in deltas). For instance, questions are raised such as whether and under which conditions it is acceptable to plan and protect new neighbourhoods in areas far below sea level or prohibit urbanisation in areas of increasing flood exposure (‘proactive spatial planning’). Future research can contribute to dealing with flood risk by exploring resistance capacities of employed measures, early warning signals of their failure and possibilities to implement innovative flood risk management approaches in the legal system.
The inconvenient truth
In the long term, current existing and planned flood risk protection measures will probably not be sufficient or desirable considering the recent IPCC projections with a likely range of global mean sea-level rise of 0.5 to 1.0 m in 2100 depending on global warming (Storyline: The future of our deltas). The report also states that 2 m in 2100 and 5 m in 2150 cannot be ruled out. Alternative measures need to be considered. With rising sea levels, failure of a dike will have an increasingly large impact on delta populations thereby raising the question of liability for potential damage.
It is increasingly evident that the shrinking solution space for adaptation in low-lying coastal areas calls for long-term dynamic pathways planning now
Marjolijn Haasnoot, associate professor of water management and climate adaptation, notes, "It is increasingly evident that the shrinking solution space for adaptation in low-lying coastal areas calls for long-term dynamic pathways planning now to inform sustainable investments on the near-term (Storyline: Pathways of delta development)". To prevent future flood catastrophes, we need to start thinking about alternative forms of flood risk management and consider managed retreat as an option to adapt to sea-level rise.
Research into this solution space should include both technical, legal and governance approaches. Postdoctoral researchers Haomiao Du and Annisa Triyanti argue, “In particular, greater attention should be paid to legal and governance perspectives in the inter- and transdisciplinary research into solution space for adaptation. Main legal and governance considerations include the understanding of the contextual dynamics and reflexivity of legal and governance systems, an effort to diversify the compatible methodologies (e.g. to involve stakeholders at an early stage, qualitative judgment in the process) and broad applications of the normative principles of legitimacy, transparency, accountability, equity and distributive justice to measure the appropriateness of a certain adaptation strategy”.
Distribution of costs and benefits
Flood risk management is expensive and therefore opens a debate about the fair distribution of public finances and people who directly benefit from the employed measures. In the future, the expense of flood protection measures will increase e.g. due to extra compensation costs for land-use limitations adjacent to these employed measures. Moreover, preparations of a potential managed retreat, e.g. to create human infrastructure in the retreat area, require financial means from which only a part of the population would benefit. This raises questions concerning financial resources as well as the distribution of responsibilities, burdens and benefits.
Coupling of objectives
During the development of an area in densely populated deltas, many different interests must be combined. The coupling of flood safety to other objectives, such as housing, nature, the energy and agricultural transition and the prevention of droughts (Storyline: Drought in deltas), is therefore challenging. This requires collaboration between different research disciplines and practitioners to explore potential synergies between these objectives, both technically and legally.
How can we reconcile rigid legal regulations, that provide the necessary certainty to make a society function in a reliable way, with often very dynamic, nature-based solutions?
For instance, by indicating possibilities and preconditions that the law offers, legal practitioners can help to co-develop creative solutions. Marleen van Rijswick, professor of European and Dutch water law, notes, "How can we reconcile rigid legal regulations, that provide the necessary certainty to make a society function in a reliable way, with often very dynamic, nature-based solutions?". Moreover, distributing responsibilities between different stakeholders and achieving sound collaboration and real synergy remains a major challenge.
A large potential of sustainable flood risk management lies in the adaptivity of citizens. Raising awareness and transferring responsibility to citizens represents a major future challenge. Tools such as FLOODLABEL, informing homeowners about their individual flood risks, can contribute to minimizing damage from waterlogging. Additionally, raising flood risk awareness of young people is an objective which should start in school.