The study, published in Geophysical Research Letters, demonstrates that this not only provides insights into the history of the Meuse but also helps to better assess future risks. Moreover, the method can be applied to rivers worldwide.
‘Barcode’
In the millimeter-thick sand layers deposited between 3,500 years ago and the 19th century, the researchers discovered a kind of “barcode” of more and fewer floods. This code shows that the Meuse follows a recurring trend of about seven to ten years in which certain years have a higher probability of flooding, as well as longer cycles of about 300 years. Strikingly, these patterns correspond to fluctuations in the so-called North Atlantic Oscillation—a climate system that influences weather patterns and storms in Western Europe.
According to the researchers, this is important news. “We see that the flood patterns of the Meuse have been strongly linked to weather conditions over the North Atlantic Ocean for thousands of years,” says VU geoscientist and co-researcher Willem Toonen. “This means that climate change can have major consequences for the river, also in the future.”
As the likelihood of flooding increases due to global warming, knowledge of such patterns is crucial. Flood records are often too short or incomplete to properly recognize these kinds of trends. By using ancient river deposits, which serve as natural archives, scientists can look much further back in time and better understand which factors are important for determining flood risks. This natural baseline and system knowledge are essential for assessing what the future may look like.
Photo: Former Earth Sciences student Sanne Rip, with the help of Kees Kasse and Hessel Woolderinksteken, takes a research drill core - by Nina van Leeuwen
