Homogenization and polarization of the seasonal water discharge of global rivers in response to climatic and anthropogenic effects

Yuanfang Chai, Yao Yue*, Lin Zhang, Chiyuan Miao, Alistair G.L. Borthwick, Boyuan Zhu, Yitian Li, A. J. Dolman

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

We investigate global trends in seasonal water discharge using data from 5668 hydrological stations in catchments whose total drainage area accounts for 2/3 of the Earth's total land area. Homogenization of water discharge, which occurs when the gap in water discharge between dry and flood seasons shrinks significantly, affects catchments occupying 2/5 of the total land area, and is mainly concentrated in Eurasia and North America. By contrast, polarization of water discharge, associated with widening of the gap in water discharge between dry and flood seasons, occurs in catchments covering 1/6 of the land area, most notably in the Amazon Basin and river basins in West Africa. Considering the major climatic and anthropogenic controlling factors, i.e. precipitation (P), evaporation (E), glacial runoff (G), and dam operations (D), the world's river basins are classified as P, DEP, GEP, and EP types. Contributions from each controlling factor to either the homogenization or polarization of the seasonal water discharge for each type of river have been analyzed. We found that homogenization of discharge is dominated by dam operations in GDEP and DEP river basins (contributing 48% and 64%) and by homogenized precipitation in GEP and EP river basins. Evaporation and precipitation are primary factors behind the polarization of discharge, contributing 56% and 41%. This study provides a basis for a possible decision tool for controlling drought/flood disasters and for assessing and preventing ecological damage in endangered regions.

Original languageEnglish
Article number136062
Pages (from-to)1-10
Number of pages10
JournalScience of the Total Environment
Volume709
Early online date18 Dec 2019
DOIs
Publication statusPublished - 20 Mar 2020

Keywords

  • Dam operations
  • Evaporation
  • Glacial runoff
  • Global trends
  • Precipitation
  • Seasonal runoff

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