Around half the world's population relies on groundwater to survive. And if you need to find out how much is available, who'll know better than the trees? A simple and scalable technology that monitors trees could solve the problem of groundwater depletion in arid and semi-arid regions.
Faculty of Science, School of Life Sciences
Google Impact Challenge
Australian Research Council Linkage Grant
Mid Coast Water
NSW Office of Water
Australia is the driest inhabited continent in the world. Our fresh water supplies are one of our most precious resources, and as our population increases and commercial use of groundwater grows, this resource is being progressively depleted.
UTS plant physiologist, Professor Derek Eamus, says over-extraction of groundwater is a significant threat to Australia, and the world’s future.
“About 40 per cent of the world is arid and semi-arid and half of the world's population living in these regions is dependent on groundwater,” he says. “Australia has had a groundwater issue for 100 years, but now India and China are facing it too.”
To begin to tackle this problem, Eamus is using trees as the canary in the coal mine. Eamus and his team have developed a sensor-based, early warning system that can assess in real-time how trees respond to the over-extraction of water.
“Our project uses a dendrometer to measure the expansion and contraction of tree stems — that happens every day through transpiration, and even more when groundwater is extracted,” Eamus says. “This technology was originally developed in civil engineering to measure the precise movement of steel beams.”
Eamus’ proposal to make innovative use of this simple and scalable technology was awarded $250 000 in the 2014 Google Impact Challenge Australia and an Australian Research Council Linkage Grant in 2015.
Eamus is partnering with Hunter Water, MidCoast Water and the state government regulator, NSW Office of Water on the project.
The team has identified the first six sites in native forest woodland near Newcastle where groundwater is pumped at a variety of depths, where they are beginning their testing.
“At the same time, we have some control sites where groundwater is too deep, more than 16 metres, so we are confident that trees are not accessing it,” he says.
“We also have exclusion zones, where we stop rain hitting the ground near the tree and instead it hits interception troughs, which pump it 10 metres away. Collars also stop rain running down the tree stem.”
Using the dendrometer that monitors the expansion and contraction of tree stems, the researchers will collect data remotely with data loggers that automatically transmit the information back to their lab. All their equipment is solar-powered.
“We plan to record many variables, including stem growth rate, stable isotope composition of leaves and root responses to changes in depth to groundwater,” Eamus says.
The information gathered will be used by the water supply industry and industry regulators to improve groundwater management.
Over three years, the project will be expanded to protect 20 of the most vulnerable sites in Australia from excessive groundwater use, and develop a system with potential to impact 1.8 billion people living in arid and semi-arid regions around the world.
“We hope to use our demonstrator sites in Australia to roll this out to other arid and semi-arid regions of the world such as India, China and the Middle East,” says Eamus. This could potentially lead to commercialisation.
Designer (tree with water drops): Tui Pritchard
Photograph supplied by Derek Eamus