Flooding – not only a matter of experts – Opinion Article

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In Europe, we are facing increasing flood risks under the influence of climate change. During the summer of 2021, the Netherlands, Germany, and Belgium experienced severe flood events due to heavy rainfall, resulting in significant damage and even casualties in Germany and Belgium. Due to climate change, such events are more likely to occur in the future.

Traditionally, in the Netherlands, mainly experts are involved in managing flood risks. This includes hydrologists and modelers accustomed to working with complex modelling software, calculating various flood scenarios, and visualizing them in a way that aligns with their knowledge and expertise. The emphasis here is on scientific accuracy rather than the visual aspects of flood information. For a long time, making flood risks and information understandable beyond a small group of experts has not been a focus point in the Netherlands.


Changing audience

However, this has changed over the last decade. Climate change and its associated risks should not only concern experts; everyone should be involved. This is especially true for flood risks, which can affect many people in the Netherlands, as almost 27% of its surface is located below sea level. Over the last decade, we have seen that improving the accessibility of flood information has different benefits.

First of all, it is important to prepare people for a potential flood event and make sure that they know what to do should such an event occur. In this way, the damage and especially the amount of casualties in case of a flood event will decrease. Furthermore, under the pressure of climate change, we need to take measures to protect our living environment. These measures can, in some cases, have a significant impact on the immediate surroundings. This includes, for example, inconvenience due to construction work, as well as the demolition of buildings to make room for improved flood defenses and dikes. To create support for these measures, it is important to involve people and inform them about the risks.   

In the Netherlands, there has been much more attention on this in recent years. An example is the website overstroomik.nl, where everyone can enter their address and see how high the water can rise, what that means in terms of accessibility to water, energy, and internet, and how they should prepare for it. While these websites are a very positive development, they are mainly focused on actionable perspectives rather than understanding the risks. Many of these initiatives do not provide or offer limited insight into the causes of a flood and the extent to which, for example, severity may vary and change in the future due to climate change. Furthermore, flood maps are generally projected in 2D and offer little insight in terms of what a flooding actually means and looks like on the ground.


Ambitions within the IMPETUS-project

Within the IMPETUS project, we believe that besides focusing on actionable perspectives, it is important to improve the accessibility of information on the causes of flooding as well. We want to make flood risks tangible and understandable for everyone. Therefore, within this project, we focus on visualizing floods in 3D. The final goal of the project is to unlock different flood scenarios, calculated with high-level expert hydrodynamic software, in a Google Street view-like environment where you can see the water rise against the buildings. Such a Google Street view-like environment is often referred to as a digital twin and is currently being developed in an increasing number of locations. In this way we can make the high-level model simulations that are normally only used by experts accessible to everyone. This could include architects, municipal policymakers in spatial planning, or simply residents of a particular area.


Technical challenges

As one can imagine, there are different (technical) challenges involved in realizing this ambition. These challenges can be summarized in two categories. The first challenge is the need to be able to simulate different types of flooding and convert the modelling results into a format that can be ‘translated’ to a 3D visualization. Secondly, an online 3D environment is needed representing the physical environment including terrain, buildings and other objects like bridges and trees.


Flood modelling

Depending on the location to which this innovation is applied, the possible causes of a flood event can be very different. For example, in the areas of the Netherlands that are located below sea level, there is always a risk that a sea dike breaches and cause the hinterland to flood. However, flooding can also be caused by high river levels (that overtop the river dikes) or by heavy precipitation. Often, flooding occurs due to a combination of these causes. In order to capture all these causes, you need a modelling software package that incorporates all the relevant processes.

For the digital modeling of floods within the IMPETUS project, we use the 3Di software. This hydrodynamic software is based on the latest mathematical insights and can simulate the motion of water in processes such as dike breaches, rainfall run-off, infiltration, overland flow, sewerage flow, river flow, and around obstacles such as bridges, buildings, and culverts, ultimately to simulate floods. More information on the 3Di software can be found here.

In addition to this simulation software, within the IMPETUS project we developed a new result format for the model simulation results. This new format is called ‘3D-tiles’, and enables you to visualize the simulation results in 3D. The 3D-tiles are developed according to the OGC-standards. These standards are the basis for many digital geospatial developments, including different digital 3D environments. Since the 3D-tiles are developed based on these standards, it is possible to visualize the simulation results in different 3D environments.


Digital modeling of the physical environment

For the modeling of the physical environment, data of all obstacles is required, including photorealistic textures of the buildings. This data is required to create the online, Google Street View-like environment, to which the flood scenarios can later be added. Within the IMPETUS-project, we work together with different organizations that already work with such an online environment and try to link to these.

In the end, within the IMPETUS project we hope to realize an online, 3D-environment in which flood simulations can be easily visualized. Such an online environment should be easy-to-use and easy-to-understand, such that important information of flood risks is accessible to everyone!

You can download the article by clicking here.


High temperatures

Record-breaking summertime temperatures have been recorded in the Netherlands in recent years. With global temperatures rising, such extreme weather events will occur more often, and for longer periods. Prolonged high temperatures, with warm nights as well as hot days, can cause heat stress* and related health issues, particularly among city populations.

*Heat stress occurs when the human body cannot get rid of excess heat and can impact wellbeing through conditions such as heat stroke, exhaustion, cramps and rashes.

"We want to enable municipality decision makers who are working on spatial developments to identify heat stress 'hot spots' and cool areas, analyse the future effects of climate change, and model the effect of different heat stress-reducing measures. The tool must provide them with an easy starting point to integrate heat stress risks in their projects."


Despite the cooling effect of the sea in the region of Zeeland, the growing risk of heat stress has become a concern.

Elderly and other vulnerable people are more impacted by the effects of prolonged heat, which can cause headaches, dizziness, insomnia and other health issues – even death. Excess temperatures also affect general comfort and liveability of cities. Water quality can be reduced, both for drinking and swimming, and infrastructure can be affected. Buildings and concrete surfaces trap heat, potentially leading to damage, and release it during the night, keeping temperatures warm.

During heat waves, it is important that everyone has access to a cool and comfortable place. Appropriate spatial planning can help to decrease and deal with heat stress. Environmental factors like water bodies, trees, and shade have a major impact on stress caused by high temperatures. Therefore, planting trees, removing concrete surfaces, creating green roofs and cool spaces can improve our comfort and health. The IMPETUS Atlantic team is developing a digital tool to support regional decision making for city planning to address these needs.


Flood risk

By 2050, sea-level within this region is predicted to rise by 15-40 cm, with more frequent extreme weather and more (severe) storms triggered by climate change. These changes will exacerbate the natural risk of flooding in the IMPETUS ‘Atlantic’ region, because it is surrounded by rivers and the sea, and is below sea level.

*Risk takes into account two aspects; the chance that an event will occur and the negative impact of such an event once it occurs. When there is a low chance that an event will occur, but its impacts are huge, the risk is still significant.

“In the Netherlands, an extensive system of dikes protects us against sea and river flooding. We have always put our faith in this defence and focused almost solely on flood prevention. However, pressure on our system will increase with climate change and rising sea levels. To adapt and maintain a safe living environment, we should develop other safety measures, like more robust spatial planning and contingency plans."


Rotterdam city, is located in Rijnmond – ‘mouth of the Rhine’. The Rhine river flows through this densely populated area and characterises the region. Protections such as sea dikes and storm surge barriers have been constructed to protect the region, but flooding still occurs.

People living in the city are accustomed to seeing smaller floods. The changing climate affects the interplay between rainfall, river levels and sea storms, increasing the flooding risk. Water levels could rise by a few metres, even in populated areas, with potentially massive impacts. 

Mitigation measures such as storm surge barriers reduce the chance that high water reaches the city, but to minimise the impact of floods when they do occur, adaptation strategies are also needed. A city that can adapt to be safe from floods must be carefully designed. How best to design such an adaptive city?

Critical infrastructure, such as hospitals and evacuation routes, must be accessible at all times. Planning how to best protect them, homes and lives is complex. Flood water behaves in a complex way and flood risks show strong spatial variations. The IMPETUS Atlantic team is developing a digital tool to support regional decision making for adaptive city planning. 


Energy and waste water

To become climate-neutral by 2050, climate mitigation* efforts are crucial in our strategy for how to deal with climate change. Reducing our energy consumption is a significant mitigation step. In the Netherlands, 15% of energy is consumed in the Rijnmond area around the port of Rotterdam, in large part by a major petrochemical industry cluster.

*Climate mitigation encompasses measures such as technologies, processes, or practices that reduce carbon emissions or enhance the sinks of greenhouse gases.


The Rotterdam port petrochemical industry cluster is Europe’s largest. It consumes 70% of the Rijnmond region’s energy. A large part of this energy is wasted (64%, 203 petajoules). More than half of that energy is lost with wastewater. In addition, most energy processes within these industries rely on fossil fuels, which has a significant impact on the climate.

Energy use must be minimised and fossil fuels should be replaced by renewable sources if climate change is to be mitigated. Electrification of processes opens up the possibility to use more renewable energy and can greatly impact decarbonisation. Recovering wasted heat would significantly reduce energy consumption and is a first step towards a more circular industry. 

Supporting industries in a transition towards climate-neutrality depends on identifying how best to reduce their carbon footprint without sacrificing production or performance. The IMPETUS Atlantic team is creating a digital tool that supports decision making about pathways towards an effective energy transition for EU industry.