Global Recharge Data Set Indicates Strengthened Groundwater Connection to Surface Fluxes. Issue 23 (29th November 2022)

• Record Type: Journal Article
• Authors: Berghuijs, Wouter R.; Luijendijk, Elco; Moeck, Christian; van der Velde, Ype; Allen, Scott T.
• Is Part Of: Geophysical research letters. Volume 49:Issue 23(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-29
• Subjects: groundwater -- aridity -- climate -- water cycle -- global models -- recharge; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL099010
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Groundwater is an invaluable global resource, but its long‐term viability as a resource for consumption, agriculture, and ecosystems depends on precipitation recharging aquifers. How much precipitation recharges groundwaters varies enormously across Earth's surface, yet recharge rates often remain uncertain. Here we use a global synthesis of field‐estimated recharge across six continents to show that globally recharge first‐order follows a simple function of climatic aridity. We use this relationship to estimate long‐term recharge in energy‐limited systems outside of permafrost regions. Our aridity‐based recharge estimates are consistent with the global field data but, on average, double previous estimates of global models. Our higher recharge estimates are likely caused by preferential groundwater recharge and discharge occurring at grid scales finer than global models. The higher recharge estimates suggest that more groundwater contributes to evapotranspiration and streamflow than previously represented by global hydrological models and global water cycle diagrams. Plain Language Summary: Groundwater is an essential resource for societies and ecosystems. The rate at which rainfall and snow replenish groundwater storage is important as it dictates the upper limit of sustainable groundwater use. Here we use measurements of groundwater recharge to show how climate determines groundwater recharge rates. Measured recharge rates, on average, strongly exceed those of models. This suggests there is more recharge globally than currently acknowledged. Consequently, also more groundwater recharge must get back to Earth's surface via river flow or water use of vegetation. Key Points: A global recharge data set indicates that climate strongly shapes the fraction of precipitation that will recharge groundwaters This recharge data set indicates more recharge globally than existing global hydrological models suggest Thus, more groundwater must contribute to evaporation and streamflow than represented by current global models and water cycle diagrams