On rainy days, a heavy flow of thick, orange sludge runs rapidly down a cleared Ballarat development site into the river below.
On days of no rain, a light trickle of sediment continues to flow into the waterway.
It is easy to see the source of the sludge while standing on the banks of the Yarrowee River in the suburb of Brown Hill.
The water runs relatively clear upstream of the 18-hectare Hillview Road residential housing development site, which has been cleared of vegetation.
Step a few metres downstream and you can see the run-off muddying the water, turning it a coffee-like colour and creating soil build-up on plants and the bank.
Concerned residents first noticed the change after heavy rain events in January.
More than six months after the first reports to the Environmental Protection Authority (EPA) and City of Ballarat, they say not much has changed.
Patience running thin
Wattle Flat Pootilla Landcare Group president Anthony Murphy, who can see the development site from his home, said he was fed up with the lack of action.
"The EPA has been working with the developer to improve the situation, but it certainly hasn't fixed it," he said.
"We have been taking photographs, other people have as well.
"It is frustrating. We are still here now, standing by the riverbank, and can see sediment is still flowing into the river.
"It is disappointing after all this time it is still happening."
The EPA and City of Ballarat said they were continuing to investigate the issue.
The developer Gull Group did not respond to the ABC's requests for comment.
A representative from the company previously told media they had complied with EPA remedial notices and introduced measures including sediment dams, mesh fabric fencing and hay bales.
Mr Murphy said more action was urgently needed, as these measures had not stopped the flow of sludge.
"We would like to see clean water coming down the stream," he said.
"We are coming into the wettest part of the year and it is a real concern it could actually get worse."
Loved community area
Friends of the Yarrowee River member Neil Huybregts said he, Mr Murphy and many other community members had worked hard to revegetate, maintain and clean up areas of the Yarrowee River.
The waterway was once treated like a dumping ground in gold mining days but council and community work had resulted in vast improvements.
Mr Huybregts said it was infuriating to see this "step backwards".
"This is just completely unnatural. It is so dense," he said.
"It impacts on the plants and animals that live in the river, the birds, the aquatic life.
"Light can't penetrate, it is getting on the plants, the plants can't grow. It has a big impact on the environment of the river."
Mr Huybregts and Mr Murphy have both raised concerns with the length of the EPA process and council monitoring of developers.
Investigations continue
City of Ballarat development and growth director Natalie Robertson said council had launched an investigation into the matter.
In a statement she said council staff monitored compliance with planning permits to ensure all developers were adhering to the conditions.
When a potential non-compliance is discovered an investigation commences and only resolves when compliance with planning permit conditions is demonstrated and the site is restored to council's satisfaction, she said.
EPA investigations into the Hillview Road site are also continuing.
