Unveiling Earth’s floodplains: a new tool that provides global topographic datasets

2019-01-23

A new paper on the Nature’s journal Scientific Data describes the first high-resolution global map of Earth’s floodplains developed by an international team of four water scientists, including Giuliano Di Baldassarre professor of hydrology at the Department of Earth Sciences at Uppsala University, and director of the Centre of Natural Hazards and Disaster Science, CNDS.

Fluvial landscape resources are of paramount importance for human development and socio-economic growth. Identifying the boundary of floodplains (areas that can potentially be flooded) is a crucial step in planning measures for flood risk reduction. Floodplain zoning is usually performed using complex hydrodynamic models, but modeling results can vary widely as they are affected by many sources of uncertainty especially in data-poor areas. With the increased availability of remote sensing technologies, however, scientists now have access to high resolution datasets with images and quantitative data on Earth’s landscape morphologies, soil and land properties at the global scale.

In this new paper, floodplain boundaries are identified capturing their unique morphology and landscape pattern implementing a fast geospatial processing tool of global topographic dataset. The geomorphic floodplain zoning tool, GFPLAIN, is freely released sharing the opportunity with scientists and professional around the globe to replicate the experiment and process regional topographic datasets producing consistent floodplain zoning in seconds or minutes at the continental scale.

Giuliano Di Baldassarre says that “despite the requirement of a limited amount of input data, the hydrogeomorphic approach is based on consolidated theories (13-16), and it is able to identify areas that can be potentially flooded, providing results comparable to the ones derived with standard approaches. Hence, we conclude that the hydrogeomorphic approach allows to easily detect floodplains, and it is therefore a useful tool for a variety of socio-economic analyses at large or global scale. Given the ease of its application, this method is an essential complement to standard event-based approaches for flood hazard mapping, especially in data-poor areas.”

“Progress made in remote sensing has truly revolutionized our capacity to monitor the Earth. Since floodplains are so important to population centers, economic activities and transportation, it is indeed critical to be able to identify their extents. With this new view of Earth's floodplains, we can now characterize the human footprint on these globally-significant environments.”

says Enrique R. Vivoni, co-author of the paper and professor at the Arizona State University (USA).

“Observing any aerial image of fluvial corridors, one can clearly distinguish floodplain boundaries, for their unique shapes and colors. These unique floodplain properties are linked to water driven erosion and deposition processes, mainly associated to historical flood events, that give shape to fluvial landforms. We found and exploit the principle that global topographic datasets implicitly contain the floodplain extent information and we released the first global geomorphic model of Earth’s floodplain together with a easy to use tool that both researchers and professional can use for their floodplain mapping projects.“ says Fernando Nardi, leading author of the paper and director of the Water Resources Research and Documentation Centre (WARREDOC) at University for Foreigners of Perugia (Italy).

The results of this research, that shares the 250m resolution dataset of global floodplains as Open Data, provide novel opportunities across diverse earth, environmental and social sciences, for advancing towards more sustainable and safer management and better understanding of complex floodplain-urban interactions, especially in data poor river basins struggling with growing human pressures.

For more information, please contact:

Giuliano Di Baldassarre, Department of Earth Sciences, Uppsala University

(giuliano.dibaldassarre-at-geo.uu.se)

Read the full article:

Fernando Nardi, Antonio Annis, Giuliano Di Baldassarre, Enrique R. Vivoni, Salvatore Grimaldi, GFPLAIN250m, a global high-resolution dataset of Earth’s floodplains, Scientific Data, 6, 180309.

Link: https://www.nature.com/articles/sdata2018309


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