Endangered turtles use Australian-first Rookwood Weir bypass

Australia Broadcast Center

22-05-2025

At first glance a series of concrete slides alongside the Rookwood Weir near Rockhampton in central Queensland may not seem like a feat of engineering.
But it is a key piece of infrastructure that has become ground zero for a national experiment looking to balance environmental conservation alongside industrial progress.
The slides work as a turtle bypass, or ladder, for several species including two that are endangered — the Fitzroy River turtle and the white-throated snapping turtle.
Sunwater executive general manager of operations Colin Bendall said the ladder was an Australian first.
"It's a substantial structure to give the turtles the capacity to get around a quite large wall in the middle of the river," Mr Bendall said.
The weir opened to much fanfare at the end of 2023 and was described by the then-state government as the biggest weir built in Australia since World War II.
Mr Bendall said while the weir itself cost almost $569 million, $4 million of that was spent on the turtle bypass and fish lock.
Some of the features include resting pools between the ramps, as well as shade and protection for the turtles to ensure they are not targets for predators while crossing.
Spanning more than 172 metres in length, the slopes are set at a 45-degree angle with textured aggregate to help the turtles climb.
Mr Bendall said while it took time for local fauna to adapt to new structures in a river system, there was evidence of turtles using the ladder in the 18 months since construction finished.
It is definitely known that a Fitzroy River turtle crossed through the passage in mid May.
But the company could not determine the exact number, despite using cameras and sound monitoring equipment.
"They mainly travel at night, and they're a bit sensitive to infrared, so it makes it a little bit difficult to catch them," Mr Bendall said.
Whether or not the passage is used is something Col Limpus will be watching with keen interest from afar.
Now retired, Dr Limpus has been researching turtles for decades and founded the Mon Repos Turtle Rookery on the Bundaberg coast.
He was also involved in developing an early prototype for the turtle ladder.
He said when research showed turtles walked along the bottom of a river or climbed near-vertical faces to get through strong currents, rather than swim, the idea for the turtle bypass was born.
He helped design one for the Tartus Weir before government funding for the project was withdrawn.
"That concept I believe has been picked up for Rookwood … but it's never been demonstrated that it actually works," Dr Limpus said.
During planning for the weir there was concern from environmental groups around the impact on the endangered turtle species, especially the possible inundation of their nests.
The ladder, and Sunwater's turtle monitoring programs, were in part a response to concerns raised in submissions to the company's Environmental Impact Statement.
According to Central Queensland University PHD student Kymberly Robinson both the Fitzroy River turtle and the white-throated snapping turtle were struggling with aging populations, specific nesting requirements, and predators.
"Almost 100 per cent of the [Fitzroy River turtle's] eggs are destroyed by different predators before they get a chance to go in the water," Ms Robinson said.
Both species can also cloacal ventilate, also known as breathing through their bottoms.
Before the weir was established Mr Bendall said Sunwater had been using sound monitoring to track more than 100 turtles in a 30-kilometre stretch of the river.
"We're also monitoring things like feral cats and pigs to make sure that they're not having an impact on [turtle] nesting zones," he said.
The research will be given to state and federal agencies for future projects.