Groundwater in Australia: Occurrence and Management Issues

Groundwater is one of Australia’s most important natural resources and is the only source of water available for many regions, supplying urban areas, agriculture, industry and mining developments. The economic value to the economy is estimated to be $A34 billion. Groundwater also sustains ecosystems, through baseflow discharges to surface water and artesian spring discharges. Groundwater is found in both sedimentary and fractured rock aquifers, with most groundwater extraction occurring from the higher yielding sedimentary aquifers including unconsolidated Quaternary alluvial sediments, consolidated sandstones and limestones in large sedimentary basins. Low salinity groundwater is generally found in higher rainfall areas around the southern coastal areas. In the arid interior, high evaporation results in salinities up to 100,000 mg/L. Deeper confined aquifers may contain older low salinity groundwaters recharged thousands of years ago. Groundwater resources have been rapidly developed over the past 40 years. Current extraction is about 5000 GL/year with 70% used for irrigation whereas in France, 60% of the total extraction of 34,000 GL/year was used for public water supplies. Early management intervention has resulted in only 2% of Australia’s management areas being over-exploited. Future challenges for groundwater management in Australia include potential impacts of climate change, impacts of mining and declining government funding.