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Flood forecasting: what next?

Easing rainfall today will start to bring some relief to flood-hit parts of eastern Australia – not immediately in many areas – and the focus will turn to improving our flood forecasting and readiness capabilities.

Australians used to rely on historical flood gauges – sometimes just a painted stick in the water – and a critical eye on the clouds to judge how river waters would rise.

Now, the Bureau of Meteorology works with a range of agencies to forecast water levels, to give severe weather warnings, and seasonal forecasts. The BOM uses satellite observations, radar images, the Internet of Things, and inflows of information from dam operators and so on to piece the picture together.

It uses data from the Himawari-8, a geostationary satellite, which orbits along with the Earth’s rotation so it points at the same place. It also uses polar orbiting satellites, which stay in orbit as the Earth rotates, and pick up more data on each pass. You can learn more about the BOM’s satellite use here.

Coverage can be patchy, and reliant on other nation’s satellites, and so some people still rely on those river gauges for flood forecasting.

But new space technologies are on the way that will mean better flood monitoring and warning systems, as well as better ways of assessing flood damage and of keeping communication channels open.

The SmartSat CRC, a consortium of industry and universities, is the backbone of Australia’s developing space industry. Chief executive officer Professor Andy Koronios says for now, Australia doesn’t have a lot of space assets for flood forecasting, but he says there are many things that will be possible as the right capabilities are developed – including new satellites that are in the pipeline.

He says Geoscience Australia uses some satellite data to do modelling, and water quality monitoring the SmartSat CRC is doing with CSIRO is useful for warnings about contamination and so on. The CSIRO Centre for Earth Observation has also bought time on the UK’s Nova-SAR1 satellite for rapid spatial mapping during natural disasters.

Director of the centre Dr Alex Held says data from NovaSAR-1 would be used to analyse the current floods.

“The data from the satellite can be used in assessing the impact of disasters such as floods – comparing the ‘before’ and ‘after’ images – to infrastructure such as bridges, roads and powerlines as well as agricultural land, coasts and natural environments,” he says.

“Flood damage assessment of the current flood event in eastern Australia is possible as we have ‘before’ images, and will have images captured during and after the floods.”

“There’s a lot that can be done,” Koronios says of building future capabilities. “Some people are thinking about using radar payloads so instead of normal optical satellites you send a signal down then measure the reflected signal that comes back.”

That relies on a Doppler effect, similar to that used in speed guns, to work out whether it’s looking at vegetation or water.

“The technology is reality now, it’s just the scale. It will be used to warn people to evacuate, to identify the rate of flow of water, the possibility of a particular area being flood, and when it will be flooded,” he says.

“You’ll get some advance warning but also it will be very useful for understanding the extent of the damage, which is important for recovery, for the safety of emergency workers, and to still have communications capabilities.”

The SmartSat CRC has been given about $6 million funding for a satellite project with new technologies, such as advanced imaging technologies, and machine learning to make sense of data from both ground sensors and those on board the satellite.

Data technology developers Inovor Technologies and Myriota are part of the project, with Myriota delivering the payload. It says that from a low Earth orbit that payload will “support data collection from ground-based sensors plus Earth observation imaging via a hyperspectral electro-optical payload”.

“Myriota’s IoT connectivity will support the collection of data about multiple weather events, including rainfall and bushfires – both of which have been impacted by climate change in recent years,” the company says.

“It’s going to be a clever little satellite,” Koronios adds.

To read more science on the NSW floods, check out our recent COSMOS Q&A and this piece from The Conversation.