In the heart of Australia, a vast, hidden resource sustains industries and communities: the Great Artesian Basin (GAB), one of the world’s largest confined aquifer systems. Understanding the health of this water source is crucial, especially for sectors like energy that rely heavily on it. A recent study published in Water Resources Research, the English translation of ‘Water Resources Research’, led by Dr. P. Castellazzi from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Environment in Urrbrae, South Australia, sheds new light on the groundwater storage changes in the GAB.
The research, which used two innovative methods to assess groundwater storage changes, reveals that despite significant depletion in the 20th century, the GAB has remained mostly stable from 2002 to 2022. This stability is a positive sign for industries that depend on this water source, including the energy sector, which uses groundwater for various processes, from drilling to power generation.
One of the methods used in the study involves the Gravity Recovery and Climate Experiment (GRACE) satellites. These satellites measure changes in Earth’s gravity field, which can be used to estimate changes in groundwater mass. “GRACE data provides a unique perspective on groundwater storage changes,” Castellazzi explains. “It allows us to look at the big picture, tracking changes over large areas and long periods.”
The other method used in the study is the groundwater budget approach. This method calculates storage change as the residual of fluxes in and out of the GAB. While both methods have their strengths, they also have their limitations. For instance, the GRACE data might overestimate increases in the GAB by attributing changes in overlying aquifers to the GAB. On the other hand, the groundwater budget approach might underestimate storage increase due to not accounting for flood recharge.
The study also found an increase in groundwater storage in the Surat sub-basin, a major recharge area. This increase is attributed to large recharge events during the study period and storage recovery following rehabilitation of free-flowing bores. This finding is particularly relevant for the energy sector, as the Surat Basin is a significant area for coal seam gas development.
The research highlights the importance of using multiple methods to assess groundwater storage changes. It also underscores the need for continued monitoring and management of the GAB to ensure its sustainability. As Castellazzi notes, “Understanding the dynamics of groundwater storage is crucial for sustainable water management. This is especially true for large, confined aquifer systems like the GAB, which play a vital role in sustaining human settlements and industries.”
This study could shape future developments in the field by encouraging a more integrated approach to groundwater management. By combining satellite data with traditional groundwater budget methods, water managers can gain a more comprehensive understanding of groundwater storage changes. This could lead to more effective water management strategies, benefiting industries like energy that rely on this vital resource.
Moreover, the research could spur further investigation into the dynamics of groundwater storage in other large, confined aquifer systems around the world. As water scarcity becomes an increasingly pressing issue, understanding and managing these hidden water resources will be more important than ever. The energy sector, in particular, will need to adapt its water management practices to ensure its operations are sustainable and resilient in the face of changing water availability.