Springs

What are GAB springs? 

The GAB springs are long-term pools of water, of varying size and form, frequently found in otherwise dry and inhospitable landscapes. The water discharged from GAB aquifers at springs comes from deep underground from a complex interconnected system of water pathways through porous rocks such as sandstone.  Water discharged at springs today varies in age, but is usually very old, having been recharged thousands to hundreds of thousands of years ago.

How do they work?

In the Triassic, Jurassic, and early Cretaceous periods, much of what is now inland Australia, was below sea level. Sand and finer deposits falling to the sea bed created the layered sedimentary rocks of the Great Artesian Basin(s).  Over time, sandstones formed and the finer sediments transformed into low permeability silt, clay and mud stones. Over geological time these rocks were uplifted forming the continent we know today.  For the last few million years, erosion has exposed sandstone and rainwater has infiltrated the permeable layers forming aquifers. The low permeability rocks act as confining layers, trapping groundwater under pressure and forming what is known as an artesian aquifer. The system of water pathways in the aquifer is complex and barriers such as geological faults can force the water up to the surface, to form an artesian spring or seep. Mound springs form when groundwater rich in dissolved salts discharges for thousands of years, creating mounds of mineral deposits. Other springs discharge warm or hot mineral waters, proving a number of outback thermal springs.

Why are springs important?

These discharge springs create distinctive wetlands with specialised ecological habitats. Because of their remote locations, unique conditions, and continuance over geological time, species have evolved that live only in GAB springs. The springs differ in size and the rate at which groundwater discharges, from small features supporting vegetation with limited open water, to larger shallow pools and the largest discharges at sites like Dalhousie in Witjira National Park, South Australia. The ecosystems supported by the GAB springs are remarkable for their biodiversity. The springs at Edgbaston Reserve in Queensland support over a dozen unique species found nowhere else.

LEARN MORE ABOUT SPRINGS

- Queensland Royal Societies Springs publication

- Lake Eyre Basin Catchment Story 

- Queensland Government Spring monitoring in the Great Artesian Basin

- Submit your photos of Springs

[link to relevant GAB articles in text or here]