Global estimation of bankfull river discharge reveals distinct flood recurrences across climate zones
Abstract Bankfull discharge, the maximum flow a river can convey before spilling over its banks, is central to modelling flood risk and understanding river-channel evolution. Global flood inundation models assume a 2-year return period for bankfull conditions, but this assumption remains untested globally. Here we use observations and machine learning to estimate bankfull discharge at ~1-km resolution along a recently developed global river network. We show that the widely used 2-year discharge reasonably approximates bankfull-flow magnitude, but bankfull return periods vary substantially within and across climate zones. Bankfull conditions occur more frequently in tropical and temperate regions (median return periods of 1.5 and 1.8 years; interquartile ranges of 2.5 and 3.2 years, respectively) and less frequently in cold and arid regions (2.8 and 4.3 years; interquartile ranges of 4.8 and 6.0 years). This variation across climate zones provides a basis for improving the representation of channel capacity in global flood models.
Authors
- Ellie Vahidi
- Daniel R. Parsons (ORCID: https://orcid.org/0000-0002-5142-4466)
- Solomon H. Gebrechorkos (ORCID: https://orcid.org/0000-0001-7498-0695)
- Hannah Cloke (ORCID: https://orcid.org/0000-0002-1472-868X)
- Boen Zhang (ORCID: https://orcid.org/0000-0002-4633-3033)
- Helen Griffith (ORCID: https://orcid.org/0000-0003-0755-4519)
- Laurence Hawker (ORCID: https://orcid.org/0000-0002-8317-7084)
- Stephen E. Darby (ORCID: https://orcid.org/0000-0001-8778-4394)
- Louise Slater (ORCID: https://orcid.org/0000-0001-9416-488X)
- Richard Boothroyd (ORCID: https://orcid.org/0000-0001-9742-4229)
- Yinxue Liu (ORCID: https://orcid.org/0000-0002-5250-0184)
- Philip J. Ashworth (ORCID: https://orcid.org/0000-0002-9642-4857)
- Julian Leyland (ORCID: https://orcid.org/0000-0002-3419-9949)
- Jiabo Yin (ORCID: https://orcid.org/0000-0002-2305-8729)
- Marcus Suassuna Santos (ORCID: https://orcid.org/0000-0002-1412-2549)
- Michel Wortmann (ORCID: https://orcid.org/0000-0002-1879-7674)
- Stuart McLelland (ORCID: https://orcid.org/0000-0002-1223-0917)
- Jeffrey Neal (ORCID: https://orcid.org/0000-0001-5793-9594)
- Pauline Delorme
- Greg Sambrook Smith
- Andrew Nicholas
- Bailey Anderson
Institutions
- Loughborough University (GB)
- University of Liverpool (GB)
- European Centre for Medium-Range Weather Forecasts (GB)
- University of Illinois Urbana-Champaign (US)
- University of Hull (GB)
- University of Exeter (GB)
- Broughton Hospital (US)
- ETH Zurich (CH)
- University of Bristol (GB)
- Wuhan University (CN)
- University of Oxford (GB)
- Jeremy Benn Associates (United Kingdom) (GB)
- Serviço Geológico do Brasil - CPRM (BR)
- University of Southampton (GB)
- University of Reading (GB)
- University of Birmingham (GB)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-08-18
- DOI
- https://doi.org/10.1038/s41467-026-76433-3
- Primary Topic
- Flood Risk Assessment and Management
- Type
- article
- Field-Weighted Citation Impact
- 0.00