Flood risk in Europe: a case study with World Bank and EU Commission

Natural hazards such as flooding and earthquakes have a significant economic and social impact on EU Member States, which is expected to increase in some areas in the future due to climate change, population change and economic growth.

And, while the argument for investing in measures to strengthen disaster resilience is strong, a lack of data and analytics about the scale, location, and costs of these risks, amongst other factors, means it’s not always clear which measures are most effective or best value for money in each context.

Analysing EU risk and resilience

The World Bank undertook a technical assistance project with the European Commission’s European Civil Protection agency (DG ECHO) to overcome these barriers and analyse the costs and benefits of investing in disaster risk resilience measures.

To do so, the project needed to model natural hazard risk across all 27 EU Member States, including country level risk analysis.

Both current levels of risk and future risk due to climate change and increased economic growth had to be calculated for the hazards studied: floods, earthquake, wildfires, extreme heat and droughts.

European scale flood modelling: using JBA flood science

Modelling on such a scale, within the tight timelines of the project, required consistent, high quality coverage from models that were already readily available, with minimal development.

JBA’s probabilistic model met the requirements for academic rigour, resolution, cost and availability and so was selected to underpin flood modelling for the study.

Part of our global flood model coverage, first released in 2019 and providing probabilistic modelling worldwide for the first time, our Europe flood modelling combines high resolution flood maps, an extensive set of simulated events, and vulnerability and exposure components to provide high quality flood analysis.

Although we offer our Europe modelling at 5m resolution with bespoke components, the project used our 30m maps and broad-scale components to provide the consistency required, while still ensuring a robust, high resolution analysis.

All of our flood modelling is underpinned by JBA’s modelling engine, FLY Technology, which brings models into being at run-time rather than using pre-built components.

This enables users to change almost all data, analysis settings and methods for unprecedented customisation and model flexibility, which was key for this project.

Flexibility for improved flood analysis

Because JBA’s model for Europe was already available, the project could be focused on generating results for the specific types of exposure that the World Bank required:

  • Residential
  • Commercial
  • Industrial
  • Health
  • Education
  • Effects on the population

Vulnerability functions for residential, commercial and industrial exposure were already available in the modelling.

The flexibility of FLY meant that it was easy to introduce new vulnerability functions into the model for the education and healthcare facilities based on multiple studies in research literature.

It also meant that it was simple to generate an additional set of risk outputs for a 2050 climate scenario. By updating the Europe region of JBA’s Global Flood Event Set, the modelling could represent the change in frequency of flood events caused by future rainfall changes.

Cost-benefit of flood mitigation measures

To demonstrate the benefits of investing in flood resilience, different flood mitigation mechanisms were modelled to provide an indication of the impact that could be expected for widespread implementation.

FLY Technology again showed its flexibility as a tool for adjusting components of the risk calculation to represent the effects of four different mechanisms:

  1. Additional flood defences (modelled as defended areas with an associated level of protection)
  2. Early warning systems (modelled by adjusting the level of damage to account for actions such as temporary defences and removal of household valuables from lower stories)
  3. Property level protection (modelling reduced losses for two urban areas by selecting properties most likely to benefit from protection and modifying their vulnerability)
  4. Nature-based solutions (assessed based on the change in peak flow as a result of environmental changes made)

Results

Results from the probabilistic flood and earthquake modelling show the countries at highest risk of impacts.

In absolute terms, the countries with the largest economies and highest exposure – Germany, France, Italy – display the highest economic impacts from flood.

When looking at economic impacts as a proportion of exposure, Romania, Slovenia, Latvia and Bulgaria are ranked highest.

Figure: Breakdown of average annual flood losses by sector: Top-10 countries (above) and all other countries (below).

Factors influencing the magnitude of flood impacts in different countries include the location and construction of buildings, the scale of existing flood mitigation measures such as flood defences, and the terrain and type of flooding that dominates (e.g. large rivers with broad flood plains compared to narrow, steep sided valleys prone to flash flooding).

For severe flood events with an estimated return period of 1 in 100-years, the country-level impacts were up to 17% of GDP for some countries.

By 2050, increases in the risk from river flooding across EU Member States are estimated to be mostly in the range 10-30%.

Supporting increased flood resilience

The JBA flood risk analysis has contributed to the full economic assessment of the project, which was released in the report Financial Risk and Opportunities to Build Resilience in Europe. Overall conclusions of the economic assessment include:

  • More investment is required in mitigating disasters in Europe
  • Disaster risk financing, such as insurance, can help to limit impacts of disaster on public finances
  • Mitigation measures such as defences, early-warning systems, nature-based solutions, and infrastructure changes can help to reduce the risk

This report will play a vital part in not only highlighting the large-scale financial impact of natural disaster in Europe, but also supporting proposals for increasing mitigation and finance mechanisms throughout the region at government level.

This need is underlined by the July 2021 floods in Central Europe, in which over 200 people lost their lives and thousands more people were affected.

For more information on JBA's global flood modelling capabilities and how it can help you manage your risk, get in touch with the team.

 

Read the full Economics for Disaster Prevention and Preparedness in Europe report and summary highlights.