THE 2013 floods have caused massive Mary River erosion and now threaten environmental catastrophe at Hervey Bay, it was claimed in Gympie this week.
"It could be another Gladstone Harbour," Tin Can Bay fisherman and former industry environmental adviser, Joe McLeod, said yesterday.
He said he was alarmed at the state of sections of river bank near Gympie, where many tonnes of soil had gone.
Sections of river bank near Albert Park and Kidd Bridge in Gympie were "as bad as '92" when river bank slumping had caused "catastrophic damage to marine life in Hervey Bay and the Great Sandy Straits," he said.
Silt washed into the ocean had prevented light penetration and killed seagrass, starving the dugongs that fed on it. Dugong populations had been all but wiped out.
This year's double flood had hit at a time when "the environment was still healing after the similar 1992 event".
"This sort of damage is very slow to heal. It could be another Gladstone Harbour," Mr McLeod said.
"We might expect significant dugong die-offs."
Mr McLeod's comments were strongly backed Mary River Catchment Co-ordinating Committee scientist, Steve Burgess, who said the damage was widespread "from Kenilworth upwards and down to Tiaro, especially in areas without riverine tree protection".
"It's like armour for the soil," he said of streamside trees and river bed timbers, often dismissed as snags.
"Major slumping has been reported at Moy Pocket, Skyring Creek, Traveston Crossing, Gympie and Tiaro."
The problem was not so much flooding as unanchored soil on cleared river banks.
"That's what a flood plain does, it floods," he said.
"The slumping is also an effect of streamside management. I'm hoping to suggest some ideas which should be considered among changes to the Water and Vegetation Act.
"There's a reason for green zones in streamside vegetation areas. Even river bed snags have their role in holding the river bottom in place."
- Major river bank slumping from Kenilworth to Tiaro
- Potential 'Gladstone Harbour' effect on Hervey Bay
- Dugong catastrophe 'probable'
- Streamside clearing a factor
- Farmers hurt by loss of land