Ground water, particularly from the Great Artesian Basin (GAB), is critical to the health of ecological communities and the viability of the pastoral, mining and tourism industries in the South Australian Arid Lands region. In the future, there will be increasing demands on the GAB due to the projected growth in mining, petroleum, and geothermal industries and how we all manage this resource will be critical.
About the GAB
The GAB is one of the largest ground water basins in the world, covering 22% of the Australian continent with an estimated water storage volume of 64,900,000,000 mega litres (ML). Taking in the north-east part of South Australia, most of Queensland, the south east corner of the Northern Territory and northern New South Wales, the GAB supplies essential water for pastoralism, urban and rural communities, and industries such as mining and tourism. Much of the artesian water in the GAB is stored under pressure. Water extractions can decrease this pressure and therefore, reduce water flow to springs and consequently impact on flora and fauna populations but ground water naturally discharges from the Basin via diffuse upward leakage and spring discharge.
Managing the GAB
- The SA Arid Lands NRM Board/National Water Commission project 'Allocating water and maintaining springs in the GAB' project researched the complex interactions between surface water and ground water resources, examined artesian pressure dynamics and studied the culturally significant natural springs that are unique in the SA Arid Lands. In addition, the location of all springs in the western margin of the GAB have been mapped for the first time and their condition in terms of flow rates and surrounding ecosystems has been recorded.
The Project reports (below) will inform the revision of the Far North Prescribed Well Area Water Allocation Plan.
- The GAB Coordinating Committee provides advice from community organisations and agencies to Ministers on efficient, effective and sustainable whole-of-resource management, and coordinates activity between stakeholders.
- In 1999 Australian and State Governments began a 15-year program known as the GAB Sustainability Initiative to cap free-flowing bores and replace open drains with pipes. As this program heads towards completion, it had achieved by mid-2013 the capping of over 1,143 wells, the removal of more than 24,843 kilometres of bore drains that have been replaced by around 27,000 kilometres of piping. This has resulted in an annual water saving of 191,862 mega litres.
- The National Partnership Agreement on Coal Seam Gas and Large Coal Mining Development was established by the Australian Government in 2011 to strengthen the regulation of coal seam gas and large coal mining developments that may have significant impacts on water resources. Fieldwork undertaken by the Department of Environment, Water and Natural Resources will inform our scientific understanding of the surface and ground water resources associated with coal bearing basins in the SA Arid Lands region.
The GAB springs are points of natural discharge of water from the aquifers of the GAB with evidence of discharge dating back two million years. Many of these springs are known as ‘mound springs’ because of the characteristic mounds associated with them. The mounds have been formed by mineralised material coming to the surface with the ancient water. The permanent nature of spring discharge and considerable changes to climate during this time has meant that the springs are home to unique flora and fauna. The significant GAB spring ecosystems are listed as endangered under the Environment Protection and Biodiversity Conservation Act 1999.
There are almost 5000 individual spring vents in 169 spring groups within the South Australian part of the GAB. The largest group is the Dalhousie complex, where more than 60 springs are located. Most springs are not mound springs but are small ‘soaks’ in the ground. Visitors to the SA Arid Lands region can witness and experience these springs at the Wabma Kadarbu Mound Springs Conservation Park
and the Witjira National Park
or can join the Friends of Parks volunteers
who work on a variety of projects within the parks. Travelling along the Oodnadatta track follows some of the GAB springs and has been a water survival path followed by Aboriginal people, explorers, and desert animals alike. Many of the GAB springs have great significance for local Aboriginal people whose ancestors not only relied on them as watering points but they also held sacred sites for important ceremonies and represented many spiritual accounts passed down through generations.
Managing the GAB Springs
In some areas of the region, artificial wetlands were created from free-flowing bores drilled into the Great Artesian Basin. Some of these wetlands are over a 100 years old and support a variety of plants and animals, including those species that depend on water in the arid zone. Since 1999 the Great Artesian Basin Sustainability Initiative
has been implemented to control free-flowing wells to protect the access to the groundwater resource for all users, including groundwater dependent ecosystems. Those artificial wetlands that remain, all have different purposes and are valued by the local community and visitors to the region. The bore-fed wetlands are wetlands that contribute to the social, recreational and amenity value of the SA Arid Lands region, especially along the Oodnadatta and Birdsville tracks where visitors to the region can experience these unique places.
Springs occur naturally where underground water (groundwater) discharges to the surface, or where the natural or modified topography of a watercourse, wetland or lake intersects the underground water table. In addition to the Great Artesian Basin springs, the region is also dotted with other springs that are permanent or semi-permanent in nature.