Home > Research > Publications & Outputs > Global Changes in 20-Year, 50-Year, and 100-Yea...

Electronic data

  • 2020GL091824

    Rights statement: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

    Final published version, 4.86 MB, PDF document

    Available under license: CC BY: Creative Commons Attribution 4.0 International License


Text available via DOI:

View graph of relations

Global Changes in 20-Year, 50-Year, and 100-Year River Floods

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • L. Slater
  • G. Villarini
  • S. Archfield
  • D. Faulkner
  • R. Lamb
  • A. Khouakhi
  • J. Yin
Article numbere2020GL091824
<mark>Journal publication date</mark>28/03/2021
<mark>Journal</mark>Geophysical Research Letters
Issue number6
Number of pages10
Publication StatusPublished
Early online date18/03/21
<mark>Original language</mark>English


Abstract Concepts like the 100-year flood event can be misleading if they are not updated to reflect significant changes over time. Here, we model observed annual maximum daily streamflow using a nonstationary approach to provide the first global picture of changes in: (a) the magnitudes of the 20-, 50-, and 100-year floods (i.e., flows of a given exceedance probability in each year); (b) the return periods of the 20-, 50-, and 100-year floods, as assessed in 1970 (i.e., flows of a fixed magnitude); and (c) corresponding flood probabilities. Empirically, we find the 20-/50-year floods have mostly increased in temperate climate zones, but decreased in arid, tropical, polar, and cold zones. In contrast, 100-year floods have mostly decreased in arid/temperate zones and exhibit mixed trends in cold zones, but results are influenced by the small number of stations with long records, and highlight the need for continued updating of hazard assessments.