Case study How geoscience can improve water resilience for regional communities
Published:9 February 2022
In central Australia, groundwater is often the only source of water for communities, agriculture and industry.
Variable rainfall and high evaporation mean that groundwater supplies are vulnerable and there can be quality issues, such as naturally occurring high levels of salts, nitrate, fluoride, uranium, iron and arsenic.
As part of the Exploring for the Future program (2016-20), Geoscience Australia undertook geoscientific and hydrogeological investigations in the Southern Stuart Corridor (spanning 89,000 km2 in central Australia between Alice Springs and Tennant Creek) to better understand groundwater aquifers (rock layers that can store groundwater). The aim of the project was to support more reliable water supplies for communities and future agricultural use in the region.
Geoscience Australia’s investigations involved acquiring data using a range of techniques that can help picture how groundwater moves and is stored underground, such as airborne electromagnetic (AEM) surveys, drilling new monitoring bores, surface and downhole geophysical surveys, groundwater level measurements, and geochemical analysis of water samples.
On ground field surveys, such as hydrochemistry analyses, provide a direct assessment of water quality as well as allowing inferences to be drawn on how groundwater moves through the system
Southern Stuart Corridor AEM data highlights the variations of electrical conductivity in the subsurface geology. Coupled with on ground investigations, this airborne data provides insights to the regional understanding of groundwater systems. This data is available from the Geoscience Australia’s Exploring for the Future Data Discovery Portal
Using data to make informed local water management decisions
By combining the different types of information from these techniques, scientists and resource managers now have a better understanding of where and how fast the aquifers recharge as well as the places where it might be possible to store water in aquifers for future use (managed aquifer recharge). The project also improved the understanding of the geological systems (rock layers and faults) that hold groundwater and the interconnections between them.
In the Alice Springs region, which houses the largest population in central Australia of 26,000, groundwater supplying the town is mainly from aquifers within the Amadeus Basin about 10 km south of town. Data acquired by Geoscience Australia and the associated hydrogeological (water flow) model will inform local water management decisions about the size of the groundwater resource, where groundwater recharge occurs, and potential methods for increasing groundwater supply through managed aquifer recharge.
In the Tennant Creek region, stretching across 323,000 km2 with a population of 3,252, the Geoscience Australia study identified potential new groundwater supplies and developed an improved geological model of the borefields and sedimentary basins that will enable water agencies to better plan and manage Tennant Creek’s water supply.
In addition, in the Engawala region (about 200 km northeast of Alice Springs), field data identified a range of possible drilling targets, which could be used by the community as a water supply, if needed. The data has been used by the Northern Territory Power and Water Corporation to help identify drilling targets with the goal of improving water security for the Engawala community.
This study is one example, showing how a better understanding of the geology of an area can help improve water supply management, especially in areas dependant on groundwater supplies.
Reference
S.D. Hostetler, E.E. Slatter, A.A. McPherson, K.P. Tan, D.J. McInnes, J.D.H. Wischusen, J.H. Ellis. 2020. “A multidisciplinary geoscientific approach to support water resilience in communities in central Australia.” Geoscience Australia, Canberra.
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