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

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 Rajeeb, assistant professor at the University of Arlington 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.

US 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, the world is at greater risk of flooding than we realized, especially given the impact of human development on floodplains,” said Rajeeb. “In 27 years, between 1992 and 2019, the world has lost a large area of ​​600,000 square kilometers of floodplains due to human disturbances, which include infrastructure development, industry and business building and expansion of agriculture.”

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

“Mapping floodplains of the world is relatively new. While there is a growing awareness of accurately mapping floodplains and understanding flood risk, there has been no attempt 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 parts of the world.”

The study concluded that wetland habitats are at risk and that a third of the total global loss of floodplain wetlands occurred in North America. Rajeeb said the risks to the floodplains are much greater than previously understood. He and his team examined satellite images of floodplain regions 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 a person living on or near a floodplain. 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 disturbing results. For example, we have seen 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 sheds light on this vital habitat that we are losing as well as ways in which we can by reversing this trend.

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

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

Reference: “Human Changes in Global Floodplains 1992-2019” By Adnan Rajib, Qianjin Zeng, Charles R Lin, Heather E. Golden, JR Christensen, Itahusa Izibor and Chris Johnson, 28 July 2023, Available here. scientific data.
DOI: 10.1038/s41597-023-02382-x