25 October 2018

Predicting drought can now be done reliably two months in advance

Researchers of Utrecht University can predict drought in the Netherlands two months in advance. This enables us to take early measures to reduce the influence of drought. In new research brought on by the continuing drought, drought expert Niko Wanders shows that by using new models, we can take measures to protect ourselves from drought earlier.

Laag water aan de Waalkade. Foto: Tim Hahn
Extremely low water at the Waalkade in Nijmegen. Photo by: Tim Hahn.

How do we predict drought?

Even though the summer is over, we are still in a period of drought. The Rhine is at an all-time low and it is exceptionally dry. By looking at the amount of water that is available in Germany and Switzerland, we can look up to two months ahead and indicate how dry it is going to be. The question is now no longer IF we can predict drought, but how we are going to use these predictions.

Betrouwbaarheid voorspelling Rijnafvoer
The reliability of drought predictions shown on a month-to month basis. Left axis: the number of weeks in advance. The horizontal axis: the months of the year. The darker the colour, the more reliable the prediction is.

Holding on to water to limit damage

The findings by hydrologist Niko Wanders of Utrecht University in collaboration with scientists from Germany, the US and the United Kingdom can be used to better distribute the water in the Netherlands ahead of time. For instance, additional water can be stored in polders and in the IJsselmeer, or water can be kept in the higher areas by not letting it flow into the sea early on. Drinking-water companies and managers of nature reserves can also use these predictions to prevent future drought problems. Wanders can make these predictions, thanks to a model that has been developed by Utrecht University.

Drought predictions have now become so reliable that we can take measures to reduce the effects of droughts.

Besides a weather forecast, a drought forecast as well

Just like the weather forecast, Wanders hopes that drought forecasts will be used by water managers in the Netherlands every day in the near future. “For the Rhine, we can make reliable forecasts by means of information from Germany and Switzerland,” he explains. “The sea temperature can be used for that as well, even though it's difficult to predict the weather more than fourteen days in advance. By looking at how much water there is in the soil and how warm the sea is, we can estimate whether more or less water is going to flow through the Rhine in the upcoming months. We are seeing that these predictions have now become so reliable that we can also take measures to reduce the effects of droughts.”

Drought damage

Does that mean we will never be bothered by drought again? “That will not be the case, unfortunately, but every little bit gets us closer to hoping that we'll be less troubled by drought in the future,” Wanders concludes. “These predictions can help us to minimise the consequences of droughts.”

Droogte bij Lobith
The current level of the Rhine (black), compared to the average (blue) and extremely dry years (red).