Floodwaters heading to Kati Thanda-Lake Eyre are expected to partially fill the lake within weeks, but the water's journey has left devastation in its wake.

Key points: Queensland's floodwaters are expected to begin filling Kati Thanda-Lake Eyre in late March

Queensland's floodwaters are expected to begin filling Kati Thanda-Lake Eyre in late March It is not known how much water the lake will receive

It is not known how much water the lake will receive If significant inflows fill the lake it will attract a variety of birdlife, which will breed on the lake's islands

The Bureau of Meteorology (BOM) is forecasting floodwaters will soon arrive in the Warburton river system and then move into the lake, which was officially given the dual name of Kati Thanda-Lake Eyre in 2012.

"Heavy rain during early February across the upper part of the Diamantina catchment in Queensland resulted in major flooding," the BOM said.

"River levels continue to rise in the Diamantina River from the South Australia border and into the Goyder Lagoon.

"Flood impacts such as inundation of floodplains, cutting of minor roads and impact to graziers are expected.

Floodwaters near Birdsville are starting to make their way to Kati Thanda-Lake Eyre. ( Supplied: C. Ellis )

"It will take a few weeks for the water to move through the Goyder Lagoon and reach the Warburton River which flows into Kati Thanda–Lake Eyre.

"The amount of water which makes its way further downstream is uncertain, but the lake will receive some water with inflows possibly starting later in March."

The SA Department of Planning, Transport and Infrastructure has already closed several outback roads following the flood event.

Parts of the unsealed Birdsville Track are closed due to flooding, while the Cordillo Downs Road is also closed.

The flood plains of Goyder's Lagoon, north of Kati Thanda-Lake Eyre, during times of flood in September 2009. ( ABC News )

The breadth of wildlife

Kati Thanda-Lake Eyre is an ephemeral water source, meaning it only occasionally has water in it.

Wildlife zoologist Greg Johnston from Flinders University said birds and fish from Queensland made their way to Kati Thanda-Lake Eyre during flood events.

Pelicans will arrive at Kati Thanda-Lake Eyre when the water partially fills the lake. ( ABC News: Gary-Jon Lysaght )

"These flows into the lake are regular, they occur in most years, it's just a matter of the magnitude," he said.

Professor Johnston said water birds such as ducks, swans and pelicans that lived in Queensland's Channel Country arrived at Kati Thanda-Lake Eyre during the flood events.

"When there's enough water to get down to Lake Eyre they follow the rivers — almost like outback highways," he said.

"If there's enough water in Lake Eyre giving them nice safe islands to breed, where they can't be predated by dingoes and foxes, then they'll end up at Lake Eyre.

"Lake Eyre's a salt lake and you need a heck of a lot of fresh water to get down there in order for freshwater fish to survive.

Floodwaters from Queensland will travel through the Warburton river before arriving in Kati Thanda-Lake Eyre. ( ABC News: Gary-Jon Lysaght )

"It takes a little while for the hard-baked salt to actually percolate and dissolve up into the water."

Professor Johnston said that while a bulk of pelicans would leave Kati Thanda-Lake Eyre and set up new populations across the country, "quite a few" would return to the Channel Country.

Not every animal likes the water

Professor Johnston said there were animals endemic to Kati Thanda-Lake Eyre that found it difficult to survive during flood events.

"They're adapted to the normal situation, which is bone-dry salt crust," he said.

"There are beetles and lizards and all sorts of spiders. There's a scorpion there that is only found on Lake Eyre.

"When it floods it's hard times for them.

"They generally hole up in little bubbles in their burrows under the salt or they get washed up onto the beach and have a bit of a hard time for a few months."

Small beetles and lizards live at Kati Thanda-Lake Eyre when it is dry. ( ABC News: Gary-Jon Lysaght )

The heartbreak of flooding

Outback publican Trevor Wright owns Wrightsair, a charter flight company which operates over Kati Thanda-Lake Eyre from William Creek — one of Australia's smallest towns.

While he acknowledged the potential tourist interest the floodwaters would have when they reached Kati Thanda-Lake Eyre, he said the water's devastating impact could not be overlooked.

"The people that have been affected by this horrific rain event, we really need to be mindful of that," he said.

"What they're going through financially and psychologically — that has to be taken to the forefront of things.

William Creek publican Trevor Wright said the heartbreak of floods cannot be forgotten. ( ABC News: Gary-Jon Lysaght )

"When it gets to the lake, with the amount of media coverage this event has had, there's definitely an interest around Australia in it."

Mr Wright said tourist companies like Wrightsair should not be seen to take advantage of the floodwaters, because of their destruction.

"I think it'll be good for SA, but it would be better if it wasn't at Queensland's expense."

Up to half a million cattle are expected to have died as floodwaters moved through the Diamantina into Queensland's Channel Country.

In a recent visit to flood-ravaged outback Queensland Prime Minister Scott Morrison said it could take years to repair the state's cattle industry.