Water: what if there is sometimes too much of it?

We must manage water differently, given the current triple planetary crisis . That includes adapting to a changing climate. Several researchers at the Faculty of Science and Engineering are working on models to get a better grip on such changes, and to be able to make predictions. After all, a changing climate affects all sorts of things, from energy and food supplies to natural disasters such as floods.

FSE Science Newsroom | Text Charlotte Vlek | Images Leoni von Ristok

‘One of the main issues we are working on is safety,’ reports environmental scientist Winnie Leenes. ‘Sometimes, that concerns floods, such as the terrible floods of 2022 in Pakistan. But it’s also about the things we need for a certain quality of life: for renewable energy, we rely on the weather, but what if the weather changes? And what happens, for example, to our food and electricity supplies in periods of drought?’

The meltwater of the Himalayas

A PhD student of Leenes is working on the impact of climate change on the meltwater of the Himalayas. ‘Due to rising temperatures, the meltwater comes down earlier than before,’ Leenes explains. ‘And that affects agriculture in that region. Precipitation also changed: there is more rain and less snow.’

In the crop-growing season, farmers at the foot of the mountain range strongly depend on the snowmelt from higher up, but by the time they need it, it has already melted and flowed away. Essentially, the water comes too early in the season, in the form of rain and meltwater, and then no water remains for other periods. Leenes: ‘And that is unfavourable for the food supply in that area.’  

Wave-like natural disasters

Applied mathematician Julian Koellermeier is also working on safety, and particularly on natural disasters that take the form of waves, such as tsunamis, floods, and avalanches. ‘With rising sea levels, protection against potential water disasters has become more important than ever,’ Koellermeier explains.

Imagine a period of heavy rain: rivers swell and move this excess water downstream. Koellermeier: ‘A model that predicts the movement of this flowing water could easily take about a month to reach a solution.’ If you are working through a hypothetical scenario to determine how high your dikes should be, one month of calculations may suffice. But in the case of an acute natural disaster, you need the outcome within a minute or two: you want to know if, and when, this heavy rain will lead to high water spilling over the dikes.

Mathematicians have been working on these kinds of problems about fluid dynamics for hundreds of years, which has resulted in all kinds of theories and models. But a lot of these models were developed for specific applications to limit their complexity. ‘For instance, there are models for deeper waters like oceans,’ Koellermeier explains, ‘and models for shallow waters like rivers and coastlines.’ But one model that is accurate in all cases? That would take too much time to compute.

And what can we do?

Nonetheless, Koellermeier is going to take up the challenge of developing a so-called hierarchy of models that can deal with all types of surface waves. This means he and his group will develop a range of models that can be used to choose the desired accuracy and speed per situation. ‘What we want to know is how fast the wave propagates and how high it is. You can then use different models for deep and shallow water, for fast calculations and more accurate calculations, and all of these will be integrated in one software system.’ That way, a user can simply choose between fast and less accurate calculations or slow and very precise ones.  

Koellermeier advocates for more awareness of possible water disasters, while Leenes collaborates with PhD students from countries where climate adaptation is most urgent, so that they can take their knowledge back home. And what about our readers at home? Do consider the advice from earlier in this series on water research: take good care of your clothes, use less electricity, and let rainwater drain away in your garden.

On Friday 21 March 2025, the Wubbo Ockels School for Energy and Climate will organize an event on climate adaptation and water , one of the key focus areas of the School. The main questions of the day are: How can we emphasize the urgency and opportunities of climate adaptation regionally and internationally, and how can new forms of communication help us in this?

Sign up here!

This news article is the fourth and final one in a series on water research at the Faculty of Science and Engineering at the University of Groningen.

Read the other articles in this series here: