The heart of the problem is a crucial under-river sewerage tunnel renewal project by Urban Utilities.
A complication with the works about 18 months ago means the system is being overwhelmed in heavy rain.
There is no indication when the works will be completed so the outflows can stop.
Adam Bowden from Stop Raw Sewage into Brisbane Rivers and Creeks said residents have a right to expect better.
“We want people to come to Brisbane and see a beautiful [river],” Bowden said.
“If we continue on the path that we’re going, we’re not going to see that.”
According to Dr. Luke Shi from Queensland University of Technology, major rivers like the Brisbane River are capable of managing a certain volume of water.
“But very importantly, we have to bear in mind is what level of interactions we have during that peak flow period,” Shi said.
Brisbane City Council monitors levels of dangerous Enterococci bacteria at points along the river.
A reading of 500 indicates there may be “a significant risk of high levels of illness transmission”.
Readings at Colmslie after the cyclone were more than three times that level when the sewage outflow was at its highest.
However no department will draw the correlation between the two.
