Comparing flood forecasting and early warning systems in the Benelux+ region

Of course. I am a Postdoctoral Researcher focused on early-warning systems and anticipatory action for floods and droughts. Within the JCAR ATRACE programme, I lead the comparative study on Flood Forecasting and Early Warning Systems (FFEWSs) in the Benelux + region.

At the Institute for Environmental Studies (IVM), we model floods and the effect of adaptation options, such as nature-based solutions like retention ponds and reforestation and forecast-based actions such as placing flood barriers. My work involves forecasting floods and simulating processes using computer models, enhancing our ability to issue timely warnings and improve response strategies.

IVM is an interdisciplinary institute, integrating insights from climate, hydrology, individual behaviour, and policy. Our aim is to bridge the gap between natural processes and societal impacts, ultimately fostering better preparedness and interventions against floods and droughts.

We did a comparative study of early warning systems for flooding across the Benelux countries and Germany’s federal states of North Rhine-Westphalia and Rhineland-Palatinate. While much existing research tends to concentrate on forecasting, our study takes an innovative approach by examining the entire warning-response chain. We aim to understand how early warnings translate into effective actions and identify the gaps that exist in this process. To gather insights, we conducted interviews with forecasters and crisis responders to assess the operational effectiveness of these systems across the different countries.

Exactly. Crisis responders need specific insights, such as whether their fire station will be affected and if they can still access areas for emergencies. A two-meter water level poses different risks than three meters; if sandbags are only placed up to two meters, they will be useless at three.

Additionally, responders want insight into which hospitals and roads will likely be flooded. Information on the expected impacts of rising water levels is essential for their planning. Currently, Flanders has made strides in forecasting flood extent and depth, but clear thresholds for issuing warnings are still lacking. Overall, moving towards impact-based forecasting is vital. Crisis managers emphasise that this type of information is critical for their operations. However, forecast specialists highlight the challenges in providing such detailed insights.

What really drove us to do this research was to test how well those operation systems function in different countries and consequently trigger a response. Here in the Netherlands, for example, we see that flood warnings do not always reach the population, partially due to the lack of a central organisation streamlining information into one clear message. We see communication fragmentation- we have the KNMI, which gives the meteorological warnings, the water boards, which give the small river warnings and Rijkswaterstaat for the large rivers. Adding to this, people can get warnings on the news and access information from the water board website. This leads to municipalities using different sources of information, which can make it hard to get a clear picture. We observed the same in the other countries and regions covered in the research. It would be interesting to follow up on these communication gaps in flood warnings by mapping out the different flows of communication in more detail.

For me, the main message is that there is a lot of potential to learn from each other as neighbouring countries, because the approaches are quite different.

From the interviews we carried out we found out that crisis managers and emergency responders need this information to improve their operations. Moreover, IBF has the potential to improve the relationship between forecasters and stakeholders in times of crisis. IBF practices require collaboration and cooperation between many disciplines, beyond just the forecasters, but including emergency services, local governments, critical sectors (e.g. transport) and citizens themselves. Beyond improving the value of forecasts, this provides a unique opportunity to build trust between those different organisations.

On the citizen response side, our hypothesis is that the specific impact information offered by IBF leads to quicker action. For people, warnings become more serious when flood maps are included, rather than just receiving a warning like "heavy rain expected; flooding may occur in your area."

When people receive a warning message along with a predicted flood map showing that their homes are at risk, they are more likely to take the danger seriously. Although the connection between this communication method and action is still being studied, data suggests that people respond more urgently when impacts are clearly communicated. This understanding is crucial for effective emergency preparation.

It is also important to note that all countries in our study now have cell phone broadcasting for alerts, which helps communicate warnings to the mass population effectively. Unlike sirens, mobile alerts can include specific advice on what actions to take, like evacuating or using sandbags. This makes them a crucial tool for public safety during floods.

I believe the JCAR ATRACE programme stands out due to its unique transboundary bottom-up approach, which distinguishes it from typical EU projects. The project’s is defined by stakeholders in countries sharing river systems: policy makers and researchers have jointly defined research questions that serve policy. Strong outreach efforts helped me significantly; people often recognised JCAR ATRACE, making it easier to secure interviews. I had no trouble engaging with over ten organisations willing to discuss their work, largely thanks to JCAR's extensive network across numerous countries. Our collaboration as a large group of authors also facilitated support and contributions across the board.

This study has proven that the close collaboration between researchers, practitioners and policymakers is essential and that our cooperation is the only way we can provide realistic and useful scientific results. We want to again thank you for this.