“The world is at greater risk of flooding than we realized” – revealing the shocking extent of human impact on global floodplains

A new study provides the first global assessment of human-induced changes to natural floodplains, highlights significant loss over 27 years, and offers insights for restoring and conserving these vital ecosystems. Collaborative efforts, using satellite data and geospatial analyses, underscore the urgent need for informed development strategies to mitigate flood risks and preserve biodiversity hotspots in these regions.

New research reveals human devastation of global floodplains

A study conducted by a hydrologist from the University of Texas at Arlington, published in the journal Scientific dataProvides an unprecedented global assessment of human impact on natural floodplains. This research can inform future development strategies, with the goal of rehabilitating and protecting essential floodplain ecosystems, which are essential for wildlife, water purity, and reducing flood risks to people.

Adnan Rajib, an assistant professor at Arlington University in the Department of Civil Engineering, was the lead author of the study. Doctoral student Qianjin Cheng played an important role in developing the research.

U.S. Environmental Protection Agency (EPA) scientists Charles Lane, Heather Golden, and Jay Christensen; Ituhausa Isibor of Texas A&M University-Kingsville; Chris Johnson of The Nature Conservancy collaborated on the study. The work was funded by NASA And the National Science Foundation.

“The bottom line is that the world is at greater risk of flooding than we realized, especially given the impact of human development on floodplains,” Rajib said. “In 27 years, between 1992 and 2019, the world has lost a whopping 600,000 square kilometers of floodplains due to human disturbances, which include infrastructure development, industry and business construction and expansion of agriculture.”

The team used satellite remote sensing data and geospatial analyzes to study 520 of the world’s major river basins, discovering previously unknown spatial patterns and trends of human floodplain changes.

“Mapping the world’s floodplains is relatively new. While there is a growing awareness to accurately map floodplains and understand flood risks, there has been no attempt to “To map human disturbances in those floodplains on a global scale.” “This has been done in smaller areas around the world, certainly in the United States and Europe, but not in data-poor areas of the world.”

The study concluded that wetland habitats are at risk and that one-third of the total global loss of floodplain wetlands occurred in North America. Rajib said that the extent of the risks on floodplains is much greater than previously understood. He and his team examined satellite images of floodplain areas taken over the past 27 years.

“We wanted to look at floodplains at the neighborhood level,” Cheng said. “We wanted to see the impact of development on someone who lives on or near floodplains. Some of the changes in these images are good, such as when trees are planted or parks are built. But many of the images reveal troubling results. For example, we saw a significant increase In developing parking lots or constructing buildings without allowing sufficient rainwater runoff.

“Floodplains around the world are biodiversity hotspots that also provide a wide range of ecosystem services to people,” said Johnson, a co-author of the paper. “We hope this study will shed light on this vital habitat we are losing as well as the ways in which we can By reversing this trend.

This study should give planners a vital tool for reducing flood risks to people, said Melanie Sattler, chair and professor of the Department of Civil Engineering.

“Rajib’s work can serve as our lens to help guide future development in order to reduce flood vulnerability in a changing climate,” Sattler said. “In some cases, we hope this study will help us correct the mistakes we made through previous development decisions.”

Reference: “Anthropogenic Changes in Global Floodplains 1992-2019” by Adnan Rajib, Qianjin Zheng, Charles R. Lin, Heather E. Golden, J.R. Christensen, Ituhausa I. Ezibor and Chris Johnson, 28 July 2023, Scientific data.
doi: 10.1038/s41597-023-02382-x