Majority of global river flow sustained by groundwater

Jiaxin Xie, Xiaomang Liu*, Scott Jasechko, Wouter R. Berghuijs, Kaiwen Wang, Changming Liu, Markus Reichstein, Martin Jung, Sujan Koirala

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

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Abstract

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—is essential for assessing fluvial nutrient cycling and contaminant transport. However, the global baseflow index remains highly uncertain, with current Earth system model simulations ranging from 12% to 94%. Here we estimate the global baseflow index to be 59% ± 7% based on an emergent constraint approach, which integrates 50 Earth system models with baseflow indices derived from streamflow observations in 15,567 basins. Our observational constraint indicates that at least 21% ± 3% of precipitation recharges groundwater, which is approximately double the figure reported in the Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change. Thus, our research suggests a more active role of groundwater in the global water cycle than most Earth system models currently simulate. We present evidence that the considerable disagreement in simulated baseflow stems from unrealistic and varied model representations of infiltration, aquifer structure and groundwater dynamics. These processes should be prioritized so that models can capture active groundwater–river connections.

Original languageEnglish
Pages (from-to)770-777
Number of pages8
JournalNature Geoscience
Volume17
Issue number8
Early online date19 Jul 2024
DOIs
Publication statusPublished - Aug 2024

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© The Author(s), under exclusive licence to Springer Nature Limited 2024.

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