Having endured droughts and floods, residents in outback NSW are dealing with the stench and clean up of millions of rotting fish as authorities work to protect drinking water.
Emergency crews face a logistical nightmare removing millions of dead fish from the Darling-Baaka River, after the worst mass death in living memory.
Huge clusters of dead fish have been found at Menindee and Pooncarie, in the state's far west, as floodwaters receded and the region was hit by repeated heatwaves in recent weeks.
The fish kills were likely caused by low levels of dissolved oxygen in the water, known as blackwater hypoxia, exacerbated by the extreme conditions.
Authorities believe it is worse than the mass deaths during the height of the drought in 2019, when water flows were low or non-existent.
An Emergency Operations Centre was set up at Menindee on Saturday and specialist contractors will be sent in to remove as many fish as possible, police said.
Assistant Commissioner Brett Greentree said it was a priority to protect the water supply at Menindee and other communities along the river.
"I'm not making promises that all the millions of fish will be removed by contractors because that is a logistical nightmare and I need to be honest with the community of Menindee," Mr Greentree told reporters in Dubbo on Monday.
Monitoring shows the drinking supply through the Menindee treatment plant is high quality.
The Central Darling Shire Council is carting water to households who rely on river water.
It will also arrange the disposal of the fish, approved by the NSW Environmental Protection Agency.
Mr Greentree hoped the removal operation could start as soon as possible.
"The Menindee community have had a real tough time of late when you look at the floods and now this as well," he said.
"So it's really important that we mobilise efficiently and as quickly as we can to do what we can to resolve this, but this is really a challenge against Mother Nature in many ways."
A community town hall meeting will be held in Menindee on Tuesday to keep residents updated.
"I can only appreciate and acknowledge the hardship," Mr Greentree said.
"The smell is something for the poor residents to put up with and it's really difficult after they've gone through a period of drought and then the floods.
"They've had a really tough time.
"That is one of the reasons why we want to move this into gear very quickly, and get some respite for the town as soon as we can.
"Unfortunately, we need to be really honest. It's not a quick fix, where we can do it in 24 hours."
State and federal agencies are continuing to monitor risks to fish health.
Timing, size and location of water releases from the Menindee Lakes into the lower Darling-Baaka River may be used to maintain the water quality.
