Sedimentary rocks (Great Artesian Basin)

Sedimentary rocks (Great Artesian Basin) – Springs and Spring Ecosystems

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The following information is correct as of 2006. Newer information on springs and spring ecosystems including GAB springs is available.

What are springs?

See FAQ page for general definition and information.

What are mound springs?

While the term mound springs is often used to describe GAB springs[4], mound springs is a loose definition encompassing a subset of all springs (GAB and non-GAB springs) which have the distinctive mound form.

Several processes may contribute to the development of mound springs:

• sand and other particles, transported by Aeolian processes, accumulate on the saturated surface of a spring;
• cemented travertine, originating from the chemical precipitation of calcium carbonate, is transported from the subsoil to the surface by groundwater and accumulates at the site of groundwater discharge;
• clay soils, saturated with groundwater at a spring, expand
• the cycle of vegetation growth and subsequent breakdown around a spring results in the development of peat layers.

Why do springs need protection?

Springs have significant environmental, economic and social values. In the Queensland GAB, the number of active springs has declined by almost 40 percent since 1900. This has had a significant impact on land quality, production values and the unique plants and animals that inhabit these wetlands. Some of these plants and animals may not be found anywhere else in Australia or the world and may be protected under legislation.

Springs are the subject of some legislative protection in Queensland including under the:

• Nature Conservation Act 1992 (presence of NCA protected species identified in database)

• Vegetation Management Act 1999

• Lands Act 1994

• Petroleum Act 1923

• Water Act 2000.

Some species that occur in springs and the spring community itself are also listed under the Commonwealth legislation Environmental Protection and Biodiversity Conservation Act (EPBC). Information on this legislation and the species and communities it seeks to protect can be accessed at www.ea.gov.au/biodiversity/threatened/index.html

Queensland Springs—distribution and assessment

The Queensland Springs database presents data from a survey of springs conducted between 1995 and 2002 for some areas of the Great Artesian Basin in Queensland (excluding Cape York Peninsula). It also includes data from other areas that is substantially incomplete. The database includes the locations of springs and their flow status (active or inactive). The presence of plant species listed as rare, vulnerable or endangered under the Nature Conservation and Other Legislation Amendment Regulation (No. 1) 2000 is also included.

Spring wetlands in seasonally arid Queensland

Seven springs in seasonally arid Queensland, including those outside the Great Artesian Basin, were listed as distinct regional ecosystems by Sattler and Williams[7] (1.10.6; 2.10.8; 4.3.22; 5.3.23; 6.3.23; 10.10.6; 11.3.22). Fensham, Fairfax and Sharpe[3] investigated the floristic variation within the spring wetlands of seasonally arid Queensland, using survey information from both Great Artesian Basin springs and permanent springs associated with other aquifers. It indicated that the regional ecosystem framework provides a satisfactory means of classifying springs. The study indicated that the flora of springs of the Great Artesian Basin aquifers are distinct from other springs in seasonally arid Queensland, but that all have substantial conservation values. The value of the springs as cultural sites, particularly for aboriginal communities, is also very high. In September 2003, an additional seven regional ecosystems (1.11.5; 2.3.39; 6.7.18; 9.8.8; 9.10.2; 10.3.31; 11.10.14) were recognised and included in the Vegetation Management Act 1999 regulation, and are described in the Regional Ecosystem Description Database.

Ecological value and conservation issues for the Great Artesian Basin springs

The springs of the Great Artesian Basin provide habitat for a number of endemic plants, as well as fish, snails and other invertebrates[5]. Fensham and Fairfax[1] described results from a comprehensive ground survey of the spring wetlands associated with the Great Artesian Basin in Queensland. That study confirmed and extended previous findings from South Australia[6] regarding the significance of the biological values of the springs emanating from the Great Artesian Basin. The conservation values of Great Artesian Basin springs have been ranked on the basis of their endemic plant populations and the habitat they provide for isolated populations of plant species[2].

The water pressure in the Great Artesian Basin has declined substantially because of the extraction of water from bores, putting the long-term sustainability of the resource at risk. This has serious implications for both the agricultural and mining sectors that use the Great Artesian Basin. A large amount of public money is being spent on rehabilitating bores with the aim of restoring aquifer pressure. Spring flows have also declined, particularly in discharge areas, and preservation of their natural values is highlighted as an important justification for the rehabilitation program (Great Artesian Basin Consultative Council 2000).

What are current threats to Great Artesian Basin spring wetlands?

The current threats are:

• reduced spring flows resulting from uncontrolled extraction of groundwater
• decreased water quality
• spring modification (such as excavation and dredging)
• inappropriate grazing and fire management
• destruction by feral pigs, goats and horses
• displacement of native vegetation by weeds and exotic pastures
• displacement of rare native fish by the exotic fish Gambusia.

Key recommendations

Key recommendations are as follows:

• negotiate conservation outcomes with land managers
• carefully control groundwater extraction to ensure impacts on groundwater flows to springs do not compromise the natural values of spring wetlands
• realise opportunities to increase spring flows in line with the historical flow rates, where possible
• improve knowledge of hydrogeology as it relates to springs
• complete bore capping including bores that may be reactivated with pressure restoration
• develop a monitoring program for changes in spring flows
• provide intensive management including the threat of Gambusia at key spring sites.

What can be done to protect the spring wetlands?

For more information, download the spring wetlands management profile or the Great Artesian Basin resource operations plan.

Queensland Springs Database
Download Queensland Springs (2006) and v4 metadata

Please contact us by email: Queensland.Herbarium♲science.dsitia.qld.gov.au
Telephone: (07) 3896 9325 fax: (07) 3896 9624

References

1. ^ Fairfax R.J. & Fensham R.J. (2003), 'Great Artesian Basin springs in southern Queensland 1911-2000', Memoirs of the Queensland Museum, vol. 49, pp. 285-293, Queensland Museum.
2. ^ Fensham, RJ & Price, RJ (2004), 'Ranking spring wetlands in the Great Artesian Basin of Australia using endemicity and isolation of plant species', Biological Conservation. [online], vol. 119, no. 1, pp. 41-50, Elsevier. Available at: Scopus.
3. ^ Fensham, RJ, Fairfax, RJ & Sharpe, PR (2004), 'Spring wetlands in seasonally arid Queensland: floristics, environmental relations, classification and conservation values.', Australian Journal of Botany. [online], vol. 50, pp. 583-583-595. Available at: http://www.southwestnrm.org.au/sites/default/files/uploads/ihub/class.pdf.
4. ^ Fensham, RJ & Fairfax, RJ (2005), Great Artesian Basin Water Resource Plan. Ecological Assessment of GAB springs in Queensland. Report for the Department of Natural Resources and Mines, Queensland Environmental Protection Agency.
5. ^ Ponder W.F. (2003), 'Endemic aquatic macro-invertebrates of artesian springs of the Great Artesian Basin - progress and future directions', Records of the South Australian Museum. Monograph Series, vol. 7, pp. 101-110, South Australian Museum.
6. ^ Ponder, WF (1995), 'Mound spring snails of the Australian Great Artesian Basin', The conservation biology of molluscs, pp. 13-18, IUCN: Gland, Switzerland, ed. E.A. Kay.
7. ^ Sattler, P & Williams, R (1999), The conservation status of Queensland bioregional ecosystems, Environmental Protection Agency, Brisbane.

Last updated: 19 May 2015