Aquifers could stave off evaporation
Experts say Australia should ‘bank water’ by using aquifers as giant underground storage tanks.
Around a third of the water stored in large above-ground reservoirs evaporates each year, as does as much as half of the supplies in farm dams.
But water banking, or Managed Aquifer Recharge (MAR), could stem that loss.
For example, the Great Artesian Basin — the world’s largest aquifer — covers of 1,700,000 square kilometres and contains more than 65 million gigalitres, according to Queensland Government statistics.
Globally, aquifer reserves are estimated to be at least 30 times larger than the total water volume found in lakes, dams and rivers.
But MAR requires sophisticated and coordinated management of water resources, both below and above ground.
The idea is relatively simple; water is deliberately injected into natural subterranean basins in times of plenty, such as during flooding or the north Australian wet season.
The reserves can then be drawn upon in a measured and managed way when needed.
If the natural systems are augmented with high-tech monitoring systems, water could be taken without the danger of depleting natural groundwater levels.
“It's very convenient,” says Professor Andrew Ross - a member of the National Centre for Groundwater Research and Training.
“Your infiltration points don't take up a lot of land, but you can take water out in quite a distributed area. It's a very stable and reliable source,” he told the ABC.
Many parts of the world (including Australia) are already drawing on groundwater reserves in potentially unsustainable ways, through bores and other access points.
MAR trials have been run in all Australian states over the past few decades, but the techniques have not made a big mark on the nation's water management.
Professor Ross says dry, fire-prone conditions of the past 12 months may inspire authorities to look closer at such schemes.
“It's important to seize the time, to make use now of the increased interest in this concept and really get it going,” he said.
Infrastructure Australia has called on the Australian Government to create a National Water Strategy to emphasise improving water security for Australia's towns and cities.