The importance of including compound events in the implementation of the Floods Directive

Water is a vital natural resource and, as such, an integral part of our environment and climate system. Excessive water exposure during flood conditions and water scarcity during droughts pose fundamental risks to life and weaken socio-economic resilience. Present-day water management in many sectors has to be able to cope with extreme hydrological conditions.

The phenomenon known as compound flooding, caused by the coincident occurrence of multiple flood drivers such as high precipitation events, storm surges or high runoff rates, has caused some of the most destructive flooding in Europe. To date, however, the compounding nature of multiple drivers has not been given sufficient consideration in current flood hazard and risk scenarios developed, for example, in the context of the European Floods Directive. This may lead to a biased assessment of flood risk, both for current and future climate conditions.

adelphi has compiled this policy brief based on the outcomes of the research project IMPREX. The brief elaborates on the importance of including compound events in the implementation of the Floods Directive. IMPREX not only provides evidence on why proper consideration of compound events is much needed in this context, but also shows how compound events can be incorporated into flood statistics, enabling better preparation and protection from some of the most destructive floods ever seen.

The policy brief concludes with concrete policy recommendations:

• Improve the understanding of compound flood events and the correlation between drivers through research.
• Raise awareness of compound events with policy and decision makers and strengthen related management capacities.
• Include compound events in the European policy framework for flood risk management.

Further policy recommendations from this project:

• Policy Brief: Probabilistic Approaches for Improved Flood Risk Assessment and Management under consideration of uncertainties
• Policy Brief: Towards successful implementation of preventive drought risk management in Europe
• Position Paper: Towards more action-oriented research and climate services – Lessons learned from IMPREX

Fact sheets:

• Innovative approaches for flood risk assessment
• Hydrometeorological predictions for the hydropower sector – potential economic benefits
• Improved forecasting and risk management for the water transport sector
• Urban water supply systems
• Drought preparedness, mitigation and management – innovative approaches for the agricultural sector
• Europe's global water risk

Comprehensive brochure:

• Improving Predictions and Management of Hydrological Extremes – Synthesized results for policy and decision makers