Interesting Facts About the Great Artesian Basin
A long, long time ago the ocean covered much of Australia. At some point, between 100 and 250 million years ago, tectonic plates shifted, forming the Great Artesian Basin. It is an area covering almost one-fourth of Australia. It is one of the largest and deepest geologic basins holding fresh water in the world, covering some 660,000 square miles and having a depth of 9,800 feet at some points.
About two million years ago, the ocean level dropped enough that only water in the basin and the still-flowing rivers surrounding it, were left. The rivers brought stones and pebbles and then the rivers dried up, leaving a sediment on the top of the water above the basin, which solidified into sandstone and rock. This sealed the water remaining in the basin. It became essentially an unknown sea under the desert Australian outback .
Here and there, water comes out naturally from the basin through mound springs. These range in temperature from 86 to 212 degrees Fahrenheit. These are popular bathing spots where people come to “take the healing waters.” Some of the water is salty, bearing traces of its oceanic origin. It is the perceived healing properties of it blend of minerals bathers seek.
Fresh water under the desert Australian outback
Although Aboriginal tribes have been settling around the hot springs for over 20,000 years, it was only fairly recently that the basin was discovered as a source of water that could be tapped and used by much of Australia’s population. In 1878, a shallow bore was sunk near Bourke, NSW. It produced flowing water. At some places where bores have been sunk, the water, under pressure, has shot into the air thirty meters or 100 feet.
The Great Artesian Basin opened up thousands of square miles, previously uninhabitable. In addition to domestic usage its water became an important supply for irrigation and livestock. To tap the water, wells are drilled to a rock layer that opens and allows the water to escape. The pressure of the water often allows its removal without pumping. Open human-made taps spewing the fresh water are endemic across Australia.
However, it was noticed as early as the early 1900s that the volume and pressure was diminishing due to the increasing number of free-flowing bores drilled .
The site of destruction and pollution
One hundred and fifty years of mismanagement are allowing the basin to be drained without anyone making use of the water that is spouting. No one knows exactly how much water is left and as with many issues environmental, where denial seems the simplest solution, many are claiming that it is a renewable resource, rather than a basin of water trapped by geologic forces, which will run dry when it is used up.
In further ignorance of the value and need of the water for human consumption, mining is allowed through the aquifer. The many chemicals used in the process of hydraulic fracturing and their long-term impact on aquifers and the agriculture and people supported by them is unknown .
Fracking fluid is a toxic brew of multiple chemicals. The composition of most fracking chemicals remains protected from disclosure through various “trade secret” exemptions under state or federal laws. Still scientists analyzing fracked fluid have identified volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene and xylene. All of these pose significant dangers to human health and welfare .
In 2011, a popular television show called ABC Four Corners highlighted concerns about chemical pollution in the Basin water as a result of coal seam gas extraction. In one incident reported in the program, the Queensland Gas Company had fracked its Myrtle 3 well connecting the Springbok aquifer to the coal seam below in 2009. A local farmer was concerned that the process may have released a potentially toxic chemical into the Basin. The gas company admitted the incident, but “did not alert authorities or nearby water users about the problem until thirteen months after the incident .”
Why is mining allowed?
According to the Great Artesian Basin Protection group, there is big money at stake. Governments receive a substantial amount of revenue from mining, and mines are huge users of the basin’s water.
The government has an incentive to spread the comforting myth that the basin is recharging from rainwater rather than expose a decision that will deplete the basin from future human domestic use in favor of a short-sighted lucrative deal.
In some instances, artesian bores and some springs have ceased to flow. This is clear evidence of depleting the resource and has also been the driver for learning more about how the Basin works and how it might respond to future conditions.
The contradictory story of the Great Artesian Basin
In what one might argue is a contradiction to its premise that the basin is recharging from rainwater, the government introduced the Great Artesian Basin Sustainability Initiative in 1999, whereby bore-owners were offered government assistance to cap uncontrolled bores and the replace open bore drains with piped water reticulation systems.
The Australian government’s website devoted to the Great Artesian Basin is as romantic as it is self-contradictory. Here is a quote taken directly:
“It is flowing, ever flowing,” crowed bush poet Banjo Paterson in 1896 in his “Song of the Artesian Water.” The tremendously and endlessly gushing waters of early bores even convinced some that the supply was ‘inexhaustible’. In a way they were right. The Great Artesian Basin will not run dry. 120 years of exploitation having used up less than 0.1 per cent of the water stored. But what declines is water pressure. When water flows from a bore, there is less pressure available to push water out of the aquifer downstream. Even before the start of the twentieth century, only a decade into the bore water boom, declining flows dashed hopes of an inexhaustible supply. In 1912, the first of many interstate conferences was called to consider remedies .
A problem on top of the problem of agreeing on whether groundwater modeling scenarios can be relied upon to predict whether the basin is being replenished by rainwater or not, is that the separate state governments are in charge of their own water. Consequently, there are continuing disputes between the national and state governments and between separate state governments about development and protection of national water resources.