They hope to understand how water penetrates these stubborn layers deep underground.

“Since fresh water holds the key to Australia’s future population, food and industries, understanding how water penetrates the various layers underground is central to how we look after and manage it,” NCGRT team member Dr Wendy Timms said.

“If we cannot tell if an overlying layer is waterproof, we can’t be sure that drilling for gas or burying hazardous wastes may not contaminate other waters above or around it.

“If we can’t be certain a layer is impermeable, we may not be able to safely store carbon dioxide below it to slow climate change.”

So far the team has measured about 100 samples of rock collected from major basins across the continent from depths of up to 1km to test the rates water can penetrate them.