Funding source: Australian Research Council, Santos, Arrow Energy, QGC

Australia, like many other water-limited regions of the world, has a dynamic hydrology cycle that sustains ecosystems, cities, and economic developments which derive benefits from the environment, such as agriculture and mining.

The natural partitioning of water between the atmosphere, aquifers and the surface varies enormously across the Australian landscape and, until very recently, has suffered minimal impact from human modification. In the last two centuries, however, human intervention has accelerated the rate of environmental change and generated new demands on water resources at all levels.

Australia’s diverse climate is characterised by extreme rainfall and prolonged droughts. Population growth has increased demands on agriculture and stretched reliable access to good quality water. The extraction of coal, gas, and minerals from underground reserves also has the potential to leave a water cycle legacy we don’t yet fully understand.

Water remains central to the future of ecosystems and humanity, and understanding how water is partitioned in the landscape is one of the most exciting scientific and management challenges happening in the physical and environmental sciences right now. UQ researchers are pioneering studies into this portioning process and what this means for what the water available to the atmosphere, the land surface, vegetation, and groundwater. They are also looking at how agriculture, mining and climate change may disrupt the cycle.

Using a combination of field monitoring and measurements, data compilation, statistical analysis, and modelling, Dr Joshua Larsen and his team are forming a better conceptual picture of Australia’s hydrology cycle and its sensitivity to change.

“One project we’re working on is looking at the natural rates at which landscapes can recharge water to aquifers,” said Professor Larsen.

“This is critical for understanding the potential long term impacts of coal seam gas extraction, for example, which draws groundwater down in the process.

“This industry and others will extract vast amounts of groundwater over the coming decade, adding cities-worth of more water to the surface part of the cycle.

“How this will be transmitted through the rest of the cycle, and how the groundwater systems will recover, remain large and very important unknowns.

“We are also looking at the beginning of streams, and how these headwater locations set the broad template for the water quality and quantity available to rivers, aquifers, and ecosystems downstream.

“It’s critical to try and understand as many pieces of the puzzle possible,” Dr Larsen said.

How Australia responds to the impacts on water partitioning from changing land use and climate conditions is being watched with interest by regions such as northern India and China, parts of the US, Africa and South America.  These nations face similar sustainability demands on the quantity and quality of freshwater from expanding agriculture and industry.