Space satellites might hold the key to better Murray-Darling Basin monitoring

Posted 16 October 2017

Satellites
Satellites could offer a solution to many of Australia’s water management challenges, with one leading researcher claiming the cost of technology would be covered by the benefits it would bring to the Murray-Darling Basin (MDB) alone. 

Director of the Australian Centre for Space Engineering Research, Andrew Dempster, assessed the potential for synthetic aperture radar (SAR) to aid water management in the MDB through soil moisture detection. He found an improvement of non-irrigated agriculture of only 0.3% would cover the cost of two satellites.

Dempster said that although building satellites big enough to garner detailed imagery is expensive, the payoff could be huge.  

“It’s got to be big and it’s got to be powerful, and this makes satellites expensive. We did a quick calculation and it came out to be about $800 million for the two satellites and the ground segment to operate those satellites,” Dempster said. 

“That sounds like a lot of money, but if it improves non-irrigated agriculture by 0.3%, the satellite pays for itself if you treat it like infrastructure.” 

“The good news is that because you control the illumination, it can work at night and it can see through clouds and smoke due to the low frequency. It’s pretty much an all-weather, 24-hours-a-day operation.”

Dempster said that low-frequency signal satellites are capable of measuring topsoil moisture, offering a range of different water management applications – including the potential to monitor and regulate irrigation application in the Murray-Darling Basin.  

“We went for l-band [frequency], which is about 1.4 gigahertz, and that signal can penetrate about 5cm into the topsoil,” he said.

“The signals that are transmitted and received can have vertical and horizontal polarisation. This means they can be used to collect information about soil moisture – the dielectric constant of the ground and how it changes if it is wet.”

And while the cost of powerful satellites would be covered by the benefit of applying them to the Murray-Darling Basin alone, there are a whole range of applications available to justify the initial expenditure. 

“You could justify the expenditure of the satellite if you just look at irrigated agriculture and Murray-Darling Basin water management, but you could keep going,” he said. 

“There are lots of things that can be achieved with satellites. It just depends on what you are looking for. The technology is already being applied internationally. It’s already been done. It’s not risky.”

And with the federal government announcing it will create a national space agency, Dempster said it’s important that real pathways are found to solve Australia’s challenges in cost-effective ways. 

“Because we don't have a space agency, we have no one looking at solving these problems using these types of solutions,” Dempster said. 

“The government has announced we are going to have a space agency but they haven't given us any details. The potential problem is that the agency that they end up implementing is not structured such that it can solve these sorts of problems. 

“What we don't want is box full of bureaucrats. We want technical people looking to solve Australian problems with Australian solutions.”
 
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