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By Chris McKay 20 March 2023 6 min read

An AquaWatch water quality sensor at Lake Tuggeranong, ACT.

On any given weekend thousands of Australians converge on the nation’s rivers, lakes and coastal waters. Whether throwing in a fishing line, paddling a kayak or surfboard, or simply jumping in to cool off, all these activities are dependent on the water being healthy enough to sustain them.

We know this because occasionally the fun is spoiled by unwelcome visitors. Toxic blue-green algal blooms, for example, are common in Australian waters and can have serious impacts on human health and the environment. Coastal dwellers will also be familiar with the debris and sediment that can show up at the beach following heavy rain.

Water quality can also be degraded by agricultural runoff, development of coastal areas, or extreme events like cyclones, floods and bushfires, which are predicted to become more frequent with the changing climate.

By 2030, however, Australians will have access to real-time information about the water quality at their favourite spots, as well as an early warning system for any potential issues. This technology is emerging from CSIRO’s new AquaWatch Australia Mission, an initiative started with Foundation Partner, SmartSat CRC.

“We’re aiming to provide forecasts of water quality 2-3 days into the future,” says Dr Alex Held, who leads AquaWatch. “It will be a weather forecast for water, like the weather app on your phone.”

AquaWatch will be the world’s first continental scale ground-to-space water quality monitoring system.

As well as the benefits for recreation, it will allow environmental managers and Traditional Owners to monitor and manage sites of important ecological and cultural significance. It could allow water managers to shut down intake of town water before a contamination event occurs. Aquaculture businesses could move fish pens or harvest oysters before a toxic algal bloom arrives.

A view of water quality from space

A satellite image of sediment plumes flowing into Keppel Bay, Queensland, following flooding in 2017. Image: European Union. Modified data from Copernicus Sentinel-2, processed with the Sentinel Hub EO Browser.

AquaWatch builds on CSIRO’s track record in Earth observation. That is, using satellites to view Earth from space.

“We can use the vantage point of space to measure water quality across vast scales,” says Dr Held.

“Different chemicals in the water absorb light in different wavelengths, giving them a unique signature, which is detected by sensors on satellites orbiting 600 km above.”

One such chemical signature is that of chlorophyll, a pigment present in algae and plants that photosynthesise, which provides information about the likelihood of algal blooms. There are other signatures for the sediment content of water, or blackwater events, as was demonstrated after the 2022 floods.

The ingenuity behind AquaWatch is that it integrates Earth observation with other science capabilities like in-situ sensing, ecosystem modelling, engineering, data science and artificial intelligence.

Sensing back down on Earth

“Sometimes, right at the moment you are hoping to get a satellite image, a cloud moves into view,” says Dr Nagur Cherukuru, who leads a project setting up pilot sites to demonstrate AquaWatch’s potential.

He’s explaining the importance of AquaWatch’s integrated ground-to-space approach, with the use of sensors down on Earth in combination with satellite data. While the satellites might only pass over a water site every 1-2 weeks, the ground-based sensors can be taking measurements in real-time and in more localised areas, whether it’s cloudy or not.

One of the buoys deployed in an AquaWatch pilot project with an array of sensors onboard. Image: CSIRO, Xiubin Qi
One of the buoys deployed in an AquaWatch pilot project with an array of sensors onboard. Image: CSIRO, Xiubin Qi

Attached to buoys or pylons in the water, networks of sensors are measuring everything from weather, water temperature and currents, to salinity levels and light absorption signatures for oxygen and algae.

The pilot sites where sensors have been installed were specifically chosen for the different water quality challenges they pose.

Keppel Bay in Queensland is one such site, where the mouth of the Fitzroy River flows out adjacent to the Great Barrier Reef. Cyclones and heavy rainfall are also common here.

“There is intensive agriculture in the Fitzroy River catchment, so any extreme rainfall events result in a lot of sediment running off agricultural land into the river and out into the bay,” says Gemma Kerrisk who coordinates the deployment of sensors at this site.

Sediment can block the light that aquatic organisms in the Reef area need to photosynthesise, and the runoff can also contain fertilisers, herbicides and pesticides, which can have complex biological consequences in these ecosystems. AquaWatch will allow for monitoring and management of these impacts and the ability to see the results of any management actions.

A water quality network across Australia

On the other side of the continent other sites have been established for different purposes.

“The aquaculture industry inquired about whether we could offer them advanced notification of algal blooms,” says Dr Xiubin Qi, who has helped implement the AquaWatch concept in South Australia and Western Australia. “That’s one of the main objectives that AquaWatch is aiming to achieve in Spencer Gulf.

“At Cockburn Sound in Western Australia, a container port called Westport is being developed and we have established an Aquawatch pilot site there to provide water quality information before, during, and after the port construction to assess its impact on the environment.”

Dr Cherukuru explains that the data from sensors and satellites will be brought together at a central data integration hub, where it is processed into information that can be used by water managers at each of these sites.

“AquaWatch will provide decision-ready information to water managers in a timely way and a user-friendly format”, he says.

“When there is an extreme event underway, we don’t want them worrying about processing data. We want them to be able to go to our portal and access the information they need straight away.”

An AquaWatch monitoring station deployed near fish pens in Spencer Gulf, South Australia, to support aquaculture water quality monitoring. Image: CSIRO, Xiubin Qi

Stimulating and supporting new industries

At this stage AquaWatch is reliant on data from satellites put into orbit by international space agencies. Australia’s access to this data is the result of partnerships nurtured by people like CSIRO’s Dr Held and Professor Andy Koronius, CEO and Managing Director of SmartSat CRC.

However, it seems set to be an important part of Australia’s nascent space industry.

“AquaWatch will have direct benefits for the development of the Australian space industry, particularly the satellite technology supply chain, from the manufacture of space craft right down to the development of new remote sensors,” says Professor Koronius.

“These are new business opportunities that will stimulate the Australian economy and provide opportunities for export of high-tech sensors and data analysis and modelling technology.”

The continental-scale of AquaWatch will require a mind-boggling number of sensors in Australia alone. One of the sensors being deployed, HydraSpectra, was designed and built in-house by CSIRO after the team discovered that equivalent sensors on the market were too expensive to be viable on the scale of AquaWatch.

“We can’t build them quickly enough at the moment,” says Dr Held. “There’s a real opportunity here for an Australian industry partner who can take our design, improve on it, and manufacture it on a scale that’s more economical.”

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