Rain could spell disaster for fire-ravaged region
ALTHOUGH the entire region is in desperate need of decent rainfall, environmental science experts say anything more than a drizzle could result in more devastation in the Pioneer Valley.
CQU Professor Steve Turton is a lecturer of environmental geography.
He said the Eungella Range area had a history of being a road that was prone to landslips despite the dense rainforest cover.
"Naturally, the road is very steep and when big rain events occur ... there is huge rainfall in that area," Mr Turton said.
Mr Turton described the barrage of extreme weather to hit the region recently as a "double whammy" with bad timing.
He said the impact of Cyclone Debbie, drought, extreme heat and the recent fires would all contribute to the likelihood of landslides and erosion.
And he said it had happened at the worst time, the beginning of the rainy season.
"The first rain event probably won't cause a landslip because the land is bone dry.
"That will cause slipstream impacts, it will wash off all the ash and loose sediment that will run into streams," Mr Turton said.
"A lot of ash and material will come down, which is not good for fish.
"What could lead to landslip would be a bit later in the wet season when the soil is recharged (becomes full of water).
"A big rain event will come down in February. There will be a high risk of land slipping because there is no vegetation cover and all the ingredients are there."
UQ researcher Dr Bradd Whitt specialises in agricultural landscapes and environmental change.
With a similar perspective to Mr Turton's, Dr Whitt said a small amount of rain would be "ideal" for the area.
But if a significant amount of rain fell in the area, Mr Whitt said the additional water would cause sediment to "shift".
This shift could have varying consequences on the ecosystem depending on the severity of the rain.
"If you burn a landscape on a large scale and the grass and trees are gone, heavy rain will hit straight into the soil," Dr Whitt said.
"The ideal reality is some smaller rainstorms, an inch here or there. But you will probably end up with six inches of rain in three days.
"If you have flatter country, when the rain falls, even with heavy rain things don't run off quickly.
"But in any undulating or in rocky mountainous location, things move very quickly."
Ultimately, Dr Whitt said the risk depended on the way the rain fell.
"It depends on the situation ... if (water) soaked in (was) followed (with) heavy rains, then it is the danger of mass movement," he said.
"The risk of landslides is higher once the water gets into the soils."
Bureau of Meteorology's Adam Blazak said scattered storms could hit areas of the Valley with 25-30mm of rain expected to hit the region in coming days.
"The 25mm could fall in half-an-hour, there is that chance of localised flash flooding and run-off," he said.
A cyclone adds to this risk.