The Great Artesian Basin in Australia covers 23% of the continent and contains 64,900 cubic kilometres of water.
Many years ago it was claimed on a TV science show I saw that some of the water in the basin comes from Papua New Guinea (PNG) via an underground conduit.
Is it true that the Great Artesian Basin in Australia gets some of its water from PNG and how is the water transported from PNG to Australia under the Torres Strait?
Many studies, observations and measurements indicate that a great deal of the water recharges from the eastern highlands (Great Dividing Range). This answer focuses on Governmental reports (including the CSIRO)
According to the CSIRO report Hydrostratigraphy, hydrogeology and system conceptualisation of the Great Artesian Basin (2012), the Great Artsian Basin consists of complex geological and hydrogeological features. This extensive study of the basin indicated no recharge from Papua New Guinea, stating that the recharge areas as being from folded Mesozoic rocks surrounding the basin in the central and southern parts, and Cenozoic aged recharge areas around the Gulf of Carpentaria in the north.
The recharge areas of the Great Artesian Basin are, according to the Australian Government Department of the Environment is mainly from rainfall on the highlands (near to the western margin of the Great Dividing Range) to the east of the Basin (with some from the western margin), as shown in the image below (from the Dept webpage):
Source:after Habermehl and Lau (1997). The shaded patterns broadly represent the recharge area; arrows represent modelled flow lines after Welsh (2000). Dashed lines represent spring clusters updated from Habermehl.
One major observation is that the top of Cape York is indicated as a recharge area, however, the CSIRO report details that this is recharge area is the Coen Inlier, just to the south of the shaded are. Also noted is that there is discharge into the Gulf of Carpentaria in the north - according to the CSIRO, the basin extends into the Gulf of Carpentaria. Although in all 3 reports there is no mention of recharge through the Torres Strait, the most any such discharge could influence, is the part of the basin in the Cape York/Carpentaria area.
A cross-section of a section of the basin is show in the image below (from the Queensland Government WetlandInfo webpage, clearly modelling the recharge areas (for the most part) being from the highlands on the eastern margin of the basin:
Additional References
Habermehl MA and Lau JE 1997, Hydrogeology of the Great Artesian Basin (Map at scale 1:2500000), Australian Geological Survey Organisation, Canberra
Welsh WD 2000, GABFLOW: A steady state groundwater flow model of the Great Artesian Basin, Bureau of Rural Sciences, Canberra.
If you look at early prehistoric Australia. Australia was connected to what is Indoneasia (Papua) and Papua New Guinea. There is a land bridge which the ocean rose over and it still exists today which is called the Torres Strait land bridge. The waters are a maximum of 60 feet in depth. It is not out of the question that GAB was filled up by a PNG aquifer or underground river and became salty from the Australian crust. In the Gulf of Carpentaria there is a shallow lake submerged and what is the Fly river in PNG used to flow south into this shallow lake which is part of the Gulf of Carpentaria sea bed. There is proof already that some water was shared or transferred in the prehistoric past from PNG to Australia when both shared the same land mass called Sahul.
If you look at an average precipitation map of Australia for the last decade or decades you will note that the CSIRO recharge areas are not in high precipitation zones except for the tip of Cape York. The Great Artesian Basin is fossil water and the Australian government has taken measures to shut down open bore holes which have flowed for many decades out of concern that the GAB may run out of water since the recharge rates are negligible.
