Public resources (mid-2020)

Phase 2: Public content (due for publication by mid-2020)

The second phase of UQ's GAB project will involve the production of a set of public facing materials including  videos, illustrations, flyers and mythbusting content. We will also be taking the key learnings out on the road next year, to share them with communities who live and depend on the waters of the basin.

Spoiler alert: we can tell you that instead of the Great Artesian Basin, we think it should be called the Great Artesian Basins as it is actually made up of several basins, including the Eromanga, Carpentaria, Surat and Clarence-Moreton basins. Across the vast area covered by the basins (around a fifth of Australia), there are widely varying degrees of interconnectivity across and within the basins.

A quick summary of the Great Artesian Basins

Australia is the driest inhabited continent in the world.

Fortunately, it is also home to the world’s largest artesian underground water source, the Great Artesian Basin, which underlies about a fifth of Australia.

But its waters are finite. Each year, more is used than is replaced.

With an enormous number of Australian industries and communities dependent on continued access to its waters for survival, Australia has been active in rolling out innovative programs to manage its use so it is available for many generations to come.

It is imperative to understand how it works so the extraction of water can be managed in the most sustainable way. This is difficult because all of the action happens underground.

The good news is that our understanding of the basins systems is increasing all the time due to new studies and investigation techniques.
While there is still a lot yet to discovered that could improve our understanding and management of the precious resource, dispelling the huge number of commonly held misconceptions and myths about the basin could lead to important improvements in how it is being used now.

HOW IT WAS FOUND, THEN REALISED IT WAS FINITE

  • In certain places of the Basin, the water comes to the surface naturally and collects in creeks and rivers. In some areas they create a permanent water source. We call these springs and first Australians used these throughout time as a critical source of fresh water. They supported valuable food sources including birds, mammals, reptiles, crustaceans and insects, creating an abundant hunting ground. They were hubs of activity and great cultural importance for first Australians.  
  • The springs of the Great Artesian Basins are home to an array of unique and endangered animals (such as the Endemic Snail (Jardinella sp), and a number of gobi fish species such as the red-finned blue eye) and plants (such as the Salt Pipewort (Eriocaulon carsonii)) that are found nowhere else in the world.
  • Then around 140 years ago, in 1878, a shallow bore sunk near Bourke produced flowing water, which marked the start of commercial extraction.
  • Hundreds of wells quickly became thousands as access to water opened up tracts of Australia’s arid inland.
  • Not realising the resource was finite, the early bores allowed water to gush freely. Water was wasted and evaporated.
  • Within four years there were reports of decreases in groundwater levels and spring flows.
  • Any changes to the water flow or water quality can be detrimental to these ecosystems, and there were reports of changes spreading along the network of bore drains which provided passage for feral animals and prime conditions for exotic plants, changing the landscape and putting pressure on native animals and habitats.
  • These worrying trends continued, then in 1912, within 34 years of the first bore, the States held the first meeting to discuss decreased groundwater flows. This sparked investment in specialised research and the introduction of the first of many management strategies to address the issue.
  • Over the next 100 years, research, improved regulation and management practices, collaboration between the Basin governments and between government and landholders, and has made substantial.  A major focus has been to stop wastage of the groundwater by stopping the uncontrolled flow of bores and removing open drains.     
  • This is of enormous importance to the many industries and communities which rely on the water.

ECONOMIC & SOCIAL IMPORTANCE FOR AUSTRALIA IS HIGH

  • Over the last 140 years, the number of water bores has continued to grow and there are now estimated to be over 50,000 bores across the Great Artesian Basins. A host of farms, industries and towns have grown up across the area opened up by access to this water, and the economic value from agriculture, industry and tourism alone is estimated at a conservative $12.8 billion a year.

COMMON MISCONCEPTIONS LEAD TO SUB OPTIMAL MANAGEMENT

  • The system is complex and there is a large number of myths and misconceptions, which make it difficult for people to determine the best use and management of the resource.

IT’S NOT ONE BASIN, BUT A COMPLEX HUGELY VARYING SYSTEM

  • Even its name is misleading, it should be a plural - Great Artesian Basins - as it is not one basin but several. Starting by correcting this would help to reset our thinking to stop talking about it as one entity – as in reality it is a complex jigsaw of four semi-connected hydrogeological basins.
  • These basins have different characteristics which can help inform how to manage its use. These include the size, depth, flow rates, layers, directions, geology, quality, and hugely varying level of connection and disconnection.

RAINFALL RECHARGES THE BASIN VERY SLOWLY

  • There are only small areas of the basin where rainfall can get down to the aquifers.
  • These areas are called recharge areas, and account for about 4% of the basins’ area.  Furthermore, it is estimated that only 2-3% of rainfall falling on these recharge areas makes it way down to the aquifers.
  • Rainfall outside of these areas does not affect groundwater volumes, but contributes to river flows and soil moisture.

THE WATER MOVES MUCH SLOWER THAN GLACIAL PACE

  • As you would imagine, water moving through rock goes very slowly - at a rate of around just 1 to 5 metres a year - and that’s when it’s moving easily!
  • Some of the water in the Basin is millions of years old.

IT’S NOT A BIG UNDERGROUND LAKE, BUT A HUGELY VARYING SYSTEMS OF CONNECTED AND DISCONNECTED LAYERS

  • The way groundwater is stored in the basins is actually very different to what most people imagine.
  • Most think of it as a large underground lake, but instead of a body of water, think of large layers of porous rock such as sandstone which holds water in tiny spaces between the sand grains.
  • We call this an aquifer – when samples of this layer are brought to the surface they often look like pieces of concrete and it is very hard to imagine how water can flow through this material.
  • These porous rock layers are mixed in with layers of non-porous material, such as clay, which stops the water continuing to seep downwards....
  • There can be many of these layers between the surface and the basement rock of the basin and they don’t neatly stack up on top of each other. This means the flow of the groundwater can change direction, or even almost totally stop due to the barriers.
  • New research shows that in large areas there is little evidence of connection between basins, so we should not expect changes in one location to necessarily spread to the other areas. Other areas have high levels of connection. This is important information in understanding the level of impact that might result from any development in a specific area.

ARTESIAN

  • The majority of the basins is artesian, which means the water is forced up through the bore to the surface by natural pressure, however there are some areas which do not have pressure or enough pressure to reach the surface, and those water bores need to be pumped out by windmills, or diesel, electric or solar pumps.
  • Where water does flow strongly to the surface under pressure, often it comes to the surface nearly boiling and stinking of rotten eggs, yet cooled down, it becomes a life-giving resource in an unforgiving environment.

LARGE WATER SAVING INITIATIVES

  • A large amount of money has been invested in water saving technology.
  • These days a huge amount of water is now conserved by capping the once free-flowing bores, and piping the water to tanks to be stored and used as needed. Between 1999 and 2017 700 bores were capped and 14,000km of drains replaced with piping. This has saved an enormous amount of water (estimated 207,000ML/year) from being wasted or evaporated. This contributes to the sustainable management of the groundwater and limits changes to our unique ecosystems.
  • This program is very expensive to implement and has only been achieved through a combination of government subsidies and landholder contributions.
  • There has also been an increase in metering and monitoring bores over time. This is mandatory for industry, which accounts for 20% of the Basin’s use. The introduction of industry has actually bought with it much new data, which is collected during the extensive impact assessment processes and ongoing monitoring that must be undertaken by any large extraction user.
  • There is no regulatory requirement to monitor the volume of water used for stock and domestic purposes. However, in recent years an increasing number of bore owners have been monitoring the volume of groundwater they extract. Bore owners have installed meters for their own information, or participated in university research projects, or citizen science initiatives, e.g., local monitoring groups established in collaboration with government. Citizen science monitoring initiatives can quickly increase the amount of publicly available bore level data, which can be collated to show performance of sustainability initiatives deployed in the area.  
  • There continues to be improvements in how we can monitor, assess and manage springs and associated health of the ecosystems.

ITS BIG, IMPORTANT & IT TAKES LARGE SCALE COLLABORATION

  • The collective volume of water in these basins has been estimated at around 64,900 million megalitres. That’s enough to fill Sydney Harbour 130,000 times.
  • Groundwater extracted from the basin has allowed an otherwise dry landscape, to become one which has supported a wide array of plant and animal life for millennia, First Australian communities for tens of thousands of years, and more recently several keystone industries, and many regional and semi-regional communities
  • It is an essential component of our unique and diverse ecosystems, our economy and our way of life
  • Australia’s Great Artesian Basins are a tremendous resource, for economic, cultural and environmental purposes.
  • Continued participation by governments, water users and researchers is needed to ensure a sufficient level of science is available.

 

 

 

Lead researcher on the GAB project, Dr Carlos Miraldo Ordens with a copy of the Hydrogeology Journal, which delivered 26 papers for the project's technical audience.  Public resources will be developed during phase two of the project.