Groundwater isotopic record in southwest Australia: links to recharge variations and climatic conditions
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Date
2018-12-10
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Publisher
Australiasian Quaternary Association Inc.
Abstract
Groundwater resources are a reliable and important source of water. Considering most large
groundwater basins can contain ‘old’ groundwater where extraction exceeds groundwater recharge,
knowledge of the past conditions and timing under which groundwater was recharged is needed to
sustainably manage groundwater resources. Applying isotopic tools to groundwater contained in
regional aquifer systems can provide low-resolution information on recharge intensity, recharge
source and past climatic conditions for the region. Furthermore, an understanding of how
groundwater recharge and climate have been connected in the past can be used to inform climate
adaptation strategies for sustaining groundwater resources during climate change.
Large regional groundwater systems, contained within the Perth Basin in southwest Australia were
investigated in this study to provide information on groundwater recharge and climate over the past
35,000 years. Regional scale databases containing groundwater age and isotopic records are not
commonly developed in Australia and are generally more site specific. Therefore, this Perth Basin
database provides a unique opportunity to study and interpret a low-resolution palaeo-archive of
groundwater recharge for southwest Australia. Groundwater ages (14CDIC) and stable O isotopes of
water (δ18O) from two regional groundwater systems within the Perth Basin have been collated and
groundwater ages calculated. The trends δ18O over time in the regional groundwater data are
consistent with the groundwater flow line data supporting our hypothesis that groundwater δ18O is
a proxy for palaeo-recharge. The Southern Perth Basin groundwater isotope record is interpreted to
be a low resolution archive of recharge driven by changes in the relative intensity of past rainfall and
recharge thresholds. This long-term stable isotopic recharge record provides a greater
understanding of groundwater palaeo-recharge, as well as how recharge and climate have been
connected in the past. © Author(s)
Description
Keywords
Ground water, Climates, Water, Water reservoirs, Isotopes, Australia, Western Australia, Groundwater recharge
Citation
Priestley, S. (2018). Groundwater isotopic record in southwest Australia: links to recharge variations and climatic conditions. Paper presented at AQUA Biennial Conference, Canberra, 10-14 December 2018. (pp. 53). https://aqua.org.au/wp-content/uploads/2019/10/AQUA-2018-Program.pdf