Germany’s Ahr river will experience severe flooding in 2021
dpa Picture Alliance / Alamy Stock Photo
It may allow us to better predict which rivers are at risk of extreme flooding, even if they have never caused severe flooding before.
It’s hard to predict extreme floods like Germany’s devastating floods in 2021, which killed at least 196 people, said Stefano Basso of the Norwegian Water Research Institute in Oslo. Typically, researchers know that a river is prone to extreme flooding only if it has experienced extreme flooding in the past. “You have to wait for something bad to happen for this method to work,” says Basso.
To find other ways to predict extreme flood risk, Basso and his colleagues analyzed runoff and flood data from 101 rivers in Germany and the United States going back at least 30 years.
They divided the flood into two groups. Small in scale, what you would expect on that river, and extreme. The second group consisted of floods that were 20 to 35 times he greater than the normal floods of a particular river.
Researchers investigated the characteristics of rivers that experienced these extreme floods. These include factors such as the magnitude and frequency of rainfall and the rate at which water flows into the river from surrounding areas.
From this analysis, the researchers came up with two parameters that appear to explain whether rivers are capable of causing extreme flooding. How much rain a river receives and how much water evaporates from its area.
Basso and his colleagues then analyzed data from 2,519 rivers in Germany and the United States going back at least 10 years, and used these two parameters to determine whether rivers could cause extreme flooding. I decided what
They identified several rivers in Germany and the United States that have not experienced extreme flooding but are considered at risk of flooding. In Germany, it includes the Remus River in Baden-Württemberg and the Wernitz and Wils rivers in Bavaria. In the United States, rivers at risk of extreme flooding include the Barron Fork of the Illinois River and the Cowpasture River in Virginia. The team is now using the model to predict which rivers in the UK are at risk of extreme flooding.
Basso says being able to predict extreme floods is important. Because authorities are often unprepared, it is these floods in urban areas that cause the most damage.
“Hydrologists have long known that the most catastrophic floods are produced by different physical processes than smaller ‘normal’ floods, but the beauty of this study is that these It’s the first time we’ve identified places that are likely to experience flooding. His Paul Bates from the University of Bristol (UK) said:
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