Northern Territory aquifer faces rapid decline visible from space
The Cambrian Limestone Aquifer (CLA), a vast network of groundwater that sustains rivers, communities, farms, and ecosystems across the NT, has been in decline since 2014. The aquifer's lowest recorded storage levels occurred in 2021, the final year of the study.
Researchers analyzed data spanning two decades (2002-2022), combining bore monitoring by the Bureau of Meteorology with satellite observations. This included data from NASA's GRACE mission, which tracks groundwater changes by detecting variations in Earth's gravity.
"This is the first time such methods have been applied to the NT," said lead researcher Dr Christopher Ndehedehe from Griffith's Australian Rivers Institute.
Between 2002 and 2013, CLA levels were relatively stable. However, from 2011 to 2022, the study recorded a marked drop in groundwater and surface features like springs and wetlands. The sharpest declines followed the 2013 approval of major irrigation licences near Mataranka and coincide with fracking developments in the Beetaloo Basin that also rely on the aquifer.
Recovery times after dry periods have also worsened, rising from under five months in 2014 to more than 15 months by 2021. Notably, this decline happened during a decade with fewer severe droughts than the one before.
"This research used multiple, independent sources of data, and shows that there is a serious risk of over-depletion of one of Australia's most important aquifer systems if water extraction rates continue to increase," said co-author Professor Matthew Currell of the Australian Rivers Institute.
Dr Ndehedehe added, "We need improved water regulation, and our findings highlight how satellite-based monitoring can fill critical data gaps to better inform water management strategies."
Research Report:Tracking freshwater depletion in Northern Australia: A multi-satellite approach'
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