Quantifying human alterations of floodplains across the world's major river basins

Floodplains provide essential ecosystem services; however, the loss of natural floodplains and floodplain functions caused by human alterations increases flood risks and leads to massive loss of life and property. A comprehensive, global-scale analysis is essential for preparing and implementing mitigation and adaptation strategies against increasing flood risks. To achieve this goal, we developed the first-ever spatially explicit estimates of irreversible land use changes (and hence, the human alterations) along the world's floodplains during the recent 27 years (1992-2019) at 250-m resolution. We used three input data sources for this analysis: (i) the GFPLAIN250m global floodplain extent dataset developed by Nard et al. (2019), (ii) the European Space Agency’s Climate Change Initiative (ESA-CCI) annual remotely sensed global land use products, and (iii) the Global Runoff Data Centre (GRDC) Major River Basins of the World dataset. Our results reveal a significant loss of natural floodplains worldwide, with more than 460,000 sq. km of agricultural expansion and 140,000 sq. km of new urban areas between 1992 and 2019. This dataset offers critical new insights into how floodplains are being destroyed, which will help decision-makers to reinforce strategies to conserve and restore floodplain functions and habitat.