Long-term variability in hydrological droughts and floods in Sub-Saharan Africa: New Perspectives from a 65-year daily streamflow dataset

Job Ekolu, Bastien Dieppois, Moussa Sidibe, Jonathan Eden, Yves Tramblay, Gabriele Villarini, Dhais Pena-Angulo, Gil Mahé, Jean-Emmanuel Paturel, Charles Onyutha, Marco Van De Wiel

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
11 Downloads (Pure)

Abstract

Understanding hydrological variability is of crucial importance for water resource management in sub-Saharan Africa (SSA). While existing studies typically focus on individual river basins, and suffer from incomplete records, this study provides a new perspective of trends and variability in hydrological flood and drought characteristics (frequency, duration, and intensity) across the entire SSA. This is achieved by: i) creating a 65-year long, complete daily streamflow dataset consisting of over 600 gauging stations; ii) quantifying changes in flood and drought characteristics between 1950 and 2014; iii) evaluating how decadal variability influences historical trends. Results of daily streamflow reconstructions using random forests provide satisfactory performance over most of SSA, except for parts of southern Africa. Using change-point and trend analyses, we identify three periods that characterise historical variations affecting hydrological extremes in western and central Africa, and some parts of southern Africa: i) the 1950s–60s and after the 1980s–90s, when floods (droughts) tend to be more (less) intense, more (less) frequent and more (less) persistent; and ii) the 1970s–80s, when floods (droughts) are less (more) intense, less (more) frequent and less (more) persistent. Finally, we reveal significant decadal variations in all flood and drought characteristics, which explain aperiodic increasing and decreasing trends. This stresses the importance of considering multiple time-periods when analysing recent trends, as previous assessments may have been unrepresentative of long-term changes.
Original languageEnglish
Article number128359
Number of pages17
JournalJournal of Hydrology
Volume613
Issue numberPart A
Early online date22 Aug 2022
DOIs
Publication statusPublished - Oct 2022

Bibliographical note

© 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license

Funder


Funding Information: J.E, B.D, and J.M.E thankfully acknowledge the support from Coventry University, UK, and resources offered by the Centre for Agroecology Water and Resilience (CAWR). In addition, B.D., Y.T, and J.E would like to thank the British Council and Campus-France for their financial support (Alliance Programme 2021; Grant N°: 814426699). In addition, D.P-A would like to thank the Make Our Planet Great Again programme funded by the Ministry of Europe and Foreign Affairs (Reference: mopga-postdoc-3-9989352314). Y.T and G.V acknowledge support by the Thomas Jefferson Fund of the Embassy of France in the United States and the FACE Foundation. Funding Information: The research leading to these results received funding from the Coventry University Trailblazer PhD studentship scheme, and the Alliance Programme 2021 (Grant N°: 814426699), cofounded by the British Council and Campus-France. Publisher Copyright: © 2022 The Author(s)

Keywords

  • Daily streamflow
  • Decadal to multidecadal variability
  • Gap-filling
  • Hydrological drought and floods
  • Sub-Saharan Africa
  • Trend

ASJC Scopus subject areas

  • Water Science and Technology

Fingerprint

Dive into the research topics of 'Long-term variability in hydrological droughts and floods in Sub-Saharan Africa: New Perspectives from a 65-year daily streamflow dataset'. Together they form a unique fingerprint.

Cite this