Saturday, July 12, 2025
  • Privacy Policy
  • Contact
  • Terms & Conditions
Environmental Magazine
Advertisement
  • Home
  • News
  • Climate Change
  • Energy
  • Recycling
  • Air
  • Fossil Fuels
  • Water
No Result
View All Result
Environmental Magazine
  • Home
  • News
  • Climate Change
  • Energy
  • Recycling
  • Air
  • Fossil Fuels
  • Water
No Result
View All Result
Environmental Magazine
No Result
View All Result
Home Water

What causes extreme flooding? German study weighs contributors

March 28, 2024
in Water
A A

According to a recent study by researchers at the Helmholtz Centre for Environmental Research (abbreviated as “UFZ”), the more flood-driving factors there are, the more extreme a flood is.

There are several factors that play an important role in the development of floods: air temperature, soil moisture, snow depth, and the daily precipitation in the days before a flood.

In order to better understand how individual factors contribute, the researchers looked at more than 3,500 river basins worldwide and analysed flood events between 1981 and 2020 for each. The result: precipitation appeared to be the sole determining factor in only around 25% of the almost 125,000 flood events. Soil moisture looked like the decisive factor in just over 10% of cases, and snow melt and air temperature were considered the sole factors in only around 3% of cases. In contrast, 51.6% of cases looked to be caused by at least two factors. At around 23%, the combination of precipitation and soil moisture occurs most frequently.

However, when analysing the data, the UFZ researchers say they discovered that three – or even all four – factors can be jointly responsible for a flood event. For example, temperature, soil moisture, and snow depth were decisive factors in around 5,000 floods whilst all four factors were decisive in around 1,000 flood events. And not only that: “We also showed that flood events become more extreme when more factors are involved”, said Dr Jakob Zscheischler, Head of the UFZ Department.

In the case of one-year floods, 51.6% can be attributed to several factors; in the case of five- and ten-year floods, 70.1% and 71.3% respectively can be attributed to several factors. The more extreme a flood is, the more driving factors there are and the more likely they are to interact in the event generation. This correlation often also applies to individual river basins and is referred to as flood complexity.

According to the researchers, river basins in the northern regions of Europe and America as well as in the Alpine region have a low flood complexity. This is because snow melt is the dominant factor for most floods regardless of the flood magnitude. The same applies to the Amazon basin, where the high soil moisture resulting from the rainy season is often a major cause of floods of varying severity. In Germany, the Havel and the Zusam, a tributary of the Danube in Bavaria, are river basins that have a low flood complexity.

Regions with river basins that have a high flood complexity primarily include eastern Brazil, the Andes, eastern Australia, the Rocky Mountains up to the US west coast, and the western and central European plains. In Germany, this includes the Moselle and the upper reaches of the Elbe. “River basins in these regions generally have several flooding mechanisms”, says Jakob Zscheischler. For example, river basins in the European plains can be affected by flooding caused by the combination of heavy precipitation, active snow melt, and high soil moisture.

However, the complexity of flood processes in a river basin also depends on the climate and land surface conditions in the respective river basin. This is because every river basin has its own special features. Among other things, the researchers looked at the climate moisture index, the soil texture, the forest cover, the size of the river basin, and the river gradient. “In drier regions, the mechanisms that lead to flooding tend to be more heterogeneous. For moderate floods, just a few days of heavy rainfall is usually enough. For extreme floods, it needs to rain longer on already moist soils”, says lead author Dr Shijie Jiang, who now works at the Max Planck Institute for Biogeochemistry in Jena.

The scientists used explainable machine learning for the analysis. “First, we use the potential flood drivers air temperature, soil moisture, and snow depth as well as the weekly precipitation – each day is considered as an individual driving factor – to predict the run-off magnitude and thus the size of the flood”, explains Zscheischler. The researchers then quantified which variables and combinations of variables contributed to the run-off of a particular flood and to which extent. This approach is referred to as explainable machine learning because it uncovers the predictive relationship between flood drivers and run-off during a flood in the trained model. “With this new methodology, we can quantify how many driving factors and combinations thereof are relevant for the occurrence and intensity of floods”, adds Jiang.

The researchers say the findings are expected to help predict future flood events. “Our study will help us better estimate particularly extreme floods”, said Zscheischler. Until now, very extreme floods have been estimated by extrapolating from less extreme floods. However, this is too imprecise because the individual contributing factors could change their influence for different flood magnitudes.

ShareTweetSharePinSendShare

Related Articles

Water

Yorkshire schools SuDS partnership boosts flood resilience

July 8, 2025
Water

Open-source AI models support water quality monitoring

July 8, 2025
Water

Puraffinity and US Army Corps of Engineers partner to advance PFAS remediation technologies

July 8, 2025
Water

Improving predictions of flood severity, place and time with AI

July 4, 2025
Water

Over half of Thames Water’s sewage works struggling to meet demand

July 2, 2025
Water

Clean Shipping Alliance criticises move to restrict use of scrubbers in ports

July 2, 2025

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Recommended

Atmospheric sulphur dioxide levels hit historic high in Scotland following Icelandic volcanic eruption

June 12, 2024

Oil Industry Asks Trump to Repeal Major Climate Policies

November 13, 2024

Don't miss it

Energy

What Risks Texas’ Grid Faces

July 11, 2025
Activism

California Congressman Vows to Challenge Trump’s ‘Big Ugly Bill’

July 11, 2025
Energy

Brazil’s Last Asbestos Miners Are Switching To Rare Earth Minerals. Can They Offer a Brighter Future?

July 11, 2025
Activism

Despite Catastrophic Flooding, Drought Persists in Parts of Central Texas

July 10, 2025
Energy

It Just Got Easier to Build Nuclear Power Plants in Wisconsin

July 10, 2025
News

Water stored in dams has caused a shift in Earth’s magnetic poles

July 10, 2025
Environmental Magazine

Environmental Magazine, Latest News, Opinions, Analysis Environmental Magazine. Follow us for more news about Enviroment and climate change from all around the world.

Learn more

Sections

  • Activism
  • Air
  • Climate Change
  • Energy
  • Fossil Fuels
  • News
  • Uncategorized
  • Water

Topics

Activism Air Climate Change Energy Fossil Fuels News Uncategorized Water

Recent News

What Risks Texas’ Grid Faces

July 11, 2025

California Congressman Vows to Challenge Trump’s ‘Big Ugly Bill’

July 11, 2025

© 2023 Environmental Magazine. All rights reserved.

No Result
View All Result
  • Home
  • News
  • Climate Change
  • Energy
  • Recycling
  • Air
  • Fossil Fuels
  • Water

© 2023 Environmental Magazine. All rights reserved.

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.