Pumping raw sewerage into the ocean was the cause of an outbreak of toxic E. coli bacteria that closed Darwin’s beaches four years ago, a university study has found.
The sewerage outfall known locally as the “poo shooter” at Larrakeyah beach, about 2 kilometres from Darwin’s centre, pumped raw sewerage into the ocean for 47 years.
It was pumping about 1.5 billion litres of sewerage a year before it was closed in 2011.
Charles Darwin University professor Karen Gibb led a team of researches gathering and studying water samples from across Darwin.
The team established a link between the sewerage outflow and elevated levels of E. coli at Doctors Gully and Lameroo beaches in the 2010 dry season. That year Darwin was forced to close all its beaches because of the toxic bacteria.
But she said questions still remained about what caused E. coli levels at other beaches to soar.
“In our environment where we have a lot of animals, a lot of things happening, lot of movement of tides and sediment there’ll be a huge amount of E. coli in the system anyway,” she said.
“We should actually be looking at a whole range of other indicators including pathogens to really get a good sense of risk and what actually matters to our recreational waters.
“Rapid Creek is one of several beaches were there was no single source causing the E. coli.
“Researchers say warm temperatures in the Northern Territory, sediment in the water and tidal conditions all impact the quality of the water, especially here at the mouth of the creek.”
‘It was a poonami at the time’
The Labor government in power in 2010 denied any link between elevated levels of E. coli and the sewerage outflow.
But in 2011 it promised to divert sewerage through a network of tunnels and pipelines to a treatment plant at Ludmilla as part of a $67 million program. The ocean outfall closed that year.
Deputy Chief Minister Peter Chandler, who was the Opposition environment minister at the time, said the study vindicated the Country Liberals Party’s campaign to close the poo shooter.
“The previous government said the poo shooter was not at fault for causing the algal bloom at the time,” Mr Chandler said.
“The government of the day said it did not have anything to do with it.
“But we suspected the poo shooter had a lot to do with it.
“This is a poonami of evidence – that was a headline at the time. It was a poonami at the time.”