The spectacular transformation of Lake Eyre as captured by the Landsat 8 satellite.

It's one of the great desert water systems of the world. Spanning three states and a territory, the Lake Eyre basin is a marvel.



But it's also one of the driest parts of the country. On the rare occasion when flood waters make their way to such barren areas the results are spectacular.

While many tourists flock to central Australia to see the sight of water flowing through the desert rivers and arriving at Lake Eyre, or Kati Thanda as it's known by the land's traditional owners, some of the best views of this natural wonder are to be had from space.



Piecing together months' worth of satellite imagery, we tracked flood waters for hundreds of kilometres on its journey from the Top End to the lowest natural point of Australia: Lake Eyre.

Queensland South Australia Diamantina River Goyder Lagoon Birdsville Warburton River Lake Eyre Georgina River

Even from space, the lake's salt plains are hard to miss.

A white tint in the otherwise brown, arid landscape of central Australia. Even from here you can get an idea of just how dry this region normally is.

Zoom in all the way to near the head of the Diamantina river in remote south west Queensland, and you can see just how arid things were in January this year.

"Large parts of south west Queensland had been very dry for a very long period of time," said Andrew Preece, a senior hydrologist at the Bureau of Meteorology.

But for those along the river that all started to change in March.

The brown scars near the confluence of the Georgina River and Eyre Creek were transformed after rain drenched the remote area across southern Queensland.

It was a similar story over on the Diamantina River.

Dried up riverbeds were replaced with lush green waterways.

The transformation near the source of the flood happened quickly, but as the water moved further south on its journey to Lake Eyre — about 15 metres below sea level — the spread of the water started to slow.

That's because the path to South Australia is quite flat, according to Richard Kingsford, a Lake Eyre expert and director of the Centre for Ecosystem Science at the University of New South Wales.

"It's also extensive. We're talking about hundreds of square kilometres and it's moving out in all different directions," Professor Kingsford said.

"The first flood high up in the catchment will come fast but as it spreads out over the floodplains it slows down and then it's priming the system as it fills the floodplains and water holes."

We can see one of these vast floodplains off the Diamantina River.

When these images were captured by US Geological Survey's Landsat 8 satellite in April, the floodwater was reaching its peak at Birdsville — a remote community on the edge of the Simpson Desert.

That flood peak reached a height of 5.98 metres on April 9, according to the Bureau of Meteorology (BOM). A reading the weather bureau classes as just below the moderate flood level, raising hopes further downstream that water would make its way to Lake Eyre.

More than a month after the rain first fell, the water crossed the border into South Australia and began pouring into Goyder Lagoon — a vast wetland 100 kilometres long and 30 kilometres wide. This is the end of the road for both the Diamantina River and Eyre Creek.

As water returns to areas like Goyder Lagoon, so does life. The boom in vegetation brings with it an explosion of wildlife.

"These systems go through this resting phase when it's really, really dry," Professor Kingsford explained. "Everything that's aquatic hangs out in these waterholes, some of which are perennial, and when the floods come everything starts moving."



Aquatic life like fish and turtles living in the deep waterholes feed on the freshly germinated vegetation and breed. Tiny crustacean eggs in the sediment hatch.

"The water birds [also] know it's on and they come from all different parts of Australia and feed from these very productive floodplains and many of them will breed as well."

After the wetland fills, the flood water begins snaking its way down the Warburton River — its final descent towards Lake Eyre.

Then on May 15, about two months after the first rains in Queensland, water started flowing into the lake.

A remarkable sight, when you consider the average yearly rainfall in this area is a little over 100 millimetres. Sydney gets that amount of rain in February alone, on average.

The latest shot from June showed the water spreading even further into the lake.

By blending the parts of colour imagery with frequencies beyond the visible light spectrum captured by Landsat 8, we get a much a better sense of the change that has occurred here.

While Lake Eyre isn't expected to fill this time around, parts of the system have been primed for the next big flood. More importantly, it's brought life to the region.

"I just love that country because it's so defined both in its ecology and its people around these rhythms of the river," Professor Kingsford said.

"They've been in such a dry period for so long that for them it's just a huge bonus. It injects so much to their livelihood because a lot of them graze cattle, the traditional owners like to get out onto the river system and importantly tourists are really valuing the experiences they get in these places."





Credits:

Reporting: Mark Doman

Development: Ri Liu and Nathanael Scott