The pronounced seasonality of global groundwater recharge

Scott Jasechko*, S. Jean Birks, Tom Gleeson, Yoshihide Wada, Peter J. Fawcett, Zachary D. Sharp, Jeffrey J. McDonnell, Jeffrey M. Welker

*Corresponding author for this work

Research output: Contribution to journalArticle

94 Citations (Scopus)

Abstract

Groundwater recharged by meteoric water supports human life by providing two billion people with drinking water and by supplying 40% of cropland irrigation. While annual groundwater recharge rates are reported in many studies, fewer studies have explicitly quantified intra-annual (i.e., seasonal) differences in groundwater recharge. Understanding seasonal differences in the fraction of precipitation that recharges aquifers is important for predicting annual recharge groundwater rates under changing seasonal precipitation and evapotranspiration regimes in a warming climate, for accurately interpreting isotopic proxies in paleoclimate records, and for understanding linkages between ecosystem productivity and groundwater recharge. Here we determine seasonal differences in the groundwater recharge ratio, defined here as the ratio of groundwater recharge to precipitation, at 54 globally distributed locations on the basis of 18O/16O and 2H/1H ratios in precipitation and groundwater. Our analysis shows that arid and temperate climates have wintertime groundwater recharge ratios that are consistently higher than summertime groundwater recharge ratios, while tropical groundwater recharge ratios are at a maximum during the wet season. The isotope-based recharge ratio seasonality is consistent with monthly outputs from a global hydrological model (PCR-GLOBWB) for most, but not all locations. The pronounced seasonality in groundwater recharge ratios shown in this study signifies that, from the point of view of predicting future groundwater recharge rates, a unit change in winter (temperate and arid regions) or wet season (tropics) precipitation will result in a greater change to the annual groundwater recharge rate than the same unit change to summer or dry season precipitation.

Original languageEnglish
Pages (from-to)8845-8867
Number of pages23
JournalWater Resources Research
Volume50
Issue number11
Early online date18 Nov 2014
DOIs
Publication statusPublished - Nov 2014

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Keywords

  • deuterium
  • groundwater
  • hydrology
  • oxygen-18
  • recharge
  • stable isotope

ASJC Scopus subject areas

  • Water Science and Technology

Cite this

Jasechko, S., Birks, S. J., Gleeson, T., Wada, Y., Fawcett, P. J., Sharp, Z. D., ... Welker, J. M. (2014). The pronounced seasonality of global groundwater recharge. Water Resources Research, 50(11), 8845-8867. https://doi.org/10.1002/2014WR015809