One of New South Wales' main inland rivers is being choked with woody logs and other floating debris after unprecedented flooding.
Several large rafts made of wood and other debris are blocking parts of the Macquarie River in the state's west, leaving residents concerned about erosion or even a diversion of the river itself.
Simon Cant lives on the river.
He said the Bulla Bulla anabranch to the west of the Macquarie was a concern.
In a more-than-moderate flow, the anabranch spills and falls into two creeks, and never returns to the Macquarie.
He said the water "cuts across to the Barwon River at Brewarrina, depriving the Ramsar-listed Macquarie Marshes of that water" and potentially threatening the iconic ecosystem.
With the logjams restricting the Macquarie's flow, the concern is that even more water will be diverted down these branches, changing its course.
Logjams like these are a natural phenomena on rivers, often after flooding.
Large woody debris can be important ecosystems in rivers, playing a role in providing fish habitat for breeding.
But with the unprecedented rain and flooding in the region, there are now seven such large blockages on the river.
'A big mess'
Bron Powell, the project manager of the Central Murray Darling Basin branch of OzFish, has kayaked on the Macquarie to look at the large rafts collected there.
She said the seven go almost all the way across the river, but water can still flow underneath.
"So many plastic bottles, chemical drums, fridges, tyres ... it's a big mess," Ms Powell said.
She said the logjam was causing the banks to erode because the water was forced around the blockage.
"A massive section of riverbank has been gouged out," she said, eating into farmers' land.
It's not the first time the town of Warren has had a large logjam.
Back in 2016, Warren had it behind its hospital.
Ms Powell said the council pushed it downstream.
"The drought obviously exacerbated that, a lot more trees would have died ... and with the floods last year, a lot more debris would have built up as well," she said.
'Fish don't like dark tunnels'
It's not just the presence of wood, but the type of wood that seems to be the problem.
Mr Cant said willow logs are creating many of the blockages.
"Native timbers sink and create fish habitat, willows float and then bind together to form rafts bridging from one bank to the other," he said.
And there are concerns for fish passage, as these large woody blockages could be impeding light from reaching significant stretches of water.
Ms Powell said the longest raft is about 130-metres long, with thick vegetation growing on it since it has been there for months.
"Fish don't really like swimming up dark passageways, it spooks them out," she said.
An EPA spokesperson said it has been responding to concerns about debris in the Macquarie River north of Warren and has engaged an independent expert and a multi-agency group to consider the risk and impacts of the blockages.
The advice into whether the river's flow is likely to be restricted is under review and the EPA will issue an update at the end of February.
