Linking climate to groundwater recharge – the view from underground
Presented by: Professor Andy Baker, UNSW
Produced by: IAH NSW
Date: Tuesday 11 March 2025
Time: 17:30 for an 18:00 start
Where: WSP Office – Level 27
Online: Teams link
Abstract
Australia’s National Groundwater Recharge Observing System (NGROS) is monitoring water movement from the surface to the groundwater by deploying drip water counters in underground spaces such as caves, tunnels and mines (Baker et al 2024). The results from the first two years of monitoring in southern and eastern Australia has identified the rainfall recharge thresholds needed for this ‘deep drainage’ or ‘potential recharge’ water to reach our fractured rock monitoring sites at locations that include Byaduk (VIC), Naracoorte (SA), Wombeyan (NSW) and Capricorn Caves (QLD). In these water-limited environments, the thresholds are typically greater than ~10 mm of rain over 48 hours in winter months and cooler climates and can reach over ~20 mm of rain in summer months and warmer climates (Priestley et al., 2025). These thresholds lead to a relatively small number of rainfall events each year that have sufficient magnitude to generate groundwater recharge. This leads us to consider how the number of groundwater recharge events in fractured rock environments relate to climate drivers such as El Niño and the Indian Ocean Dipole, and how we can use cave stalagmites as records of past groundwater recharge. A new five-year Australian Research Council funded project which has just commenced and that is addressing these questions is introduced.
Baker, A., et al. 2024. An underground drip water monitoring network to characterize rainfall recharge of groundwater at different geologies, environments, and climates across Australia, Geosci. Instrum. Method. Data Syst., 13, 117–129, https://doi.org/10.5194/gi-13-117-2024, 2024.
Priestley et al. 2025. Groundwater recharge of fractured rock aquifers in SE Australia is episodic and controlled by season and rainfall amount. Preprint available at https://essopenarchive.org/1252406
Bio
Andy Baker is a UNSW Sydney academic and Australian Research Council Laureate Fellow.
His research aims to generate new knowledge that is only possible by combining the analysis of cave stalagmites, underground hydrological monitoring, and climate hydrological modelling to identify when this replenishment occurred in the past, present, and future.
His research will use caves and cave stalagmites to define the role of climate phenomena such as El Niño and La Niña, and the Indian Ocean Dipole in the replenishment of groundwater.
This work will help identify where groundwater can be sustainably used for water supply and industrial use in the future and to mitigate the impacts of prolonged droughts that are predicted as result of climate change.
Andy has a number of PhD positions available for research on this topic, and can be found at About – Andy Baker
