A paper by Andrew Ross, a researcher at the National Centre for Groundwater Research and Training in Adelaide, recommends that Australia should prepare for dry times by ‘banking’ its water underground when rainfall is plentiful,

Mr Ross says that water banking offers a way to "waterproof" Australia’s major urban centres. The known capacity of aquifers to store additional water below Perth, Adelaide and Melbourne could meet the needs of 2.5 million people – and may be far larger.

The water could come from dam spills, floodwater, recycled stormwater and wastewater, irrigation drainage and water entitlement sales.

Using aquifers would avoid the high engineering and environmental cost of building dams as well as loss of water from evaporation – which can be more than a third of surface water each year.

Water banking is used in Orange County, California, where around 300 gigalitres a year – enough for 2.3 million people – is stored underground.

The Burdekin region of Queensland is already storing about 45 gigalitres for use in agriculture and horticulture.