The push to make Melbourne’s waterway swimmable despite E.coli concerns

The Yarra Riverkeepers Association now describes the river as “polluted with rubbish and urban waste”, noting that water quality in some areas has fallen well below accepted standards for safe swimming.

Janet Bolitho, president of the Riverkeepers Association, says it is “absolutely” possible for the more urban parts of the river to be as healthy as its upper reaches.

“Fifty years ago the Yarra was thought of as a joke – people said it was brown and dirty,” he says.

“Well, it’s not like that anymore. It’s much better than before. We need a next-generation replacement for buoyancy.”

The association is part of a growing worldwide movement to restore urban rivers to something close to their pre-industrial state.

From the Seine in Paris to the Thames in London, Swimmable Cities movement Led by Melburnian Matt Sykes, he fought for the right to clean and healthy urban waterways for everyone to enjoy.

The Floatable Cities Alliance, which includes nearly 200 organizations in 35 countries, grew after global attention turned to efforts to rehabilitate the Seine River during the Paris Olympics.

There is a Wurundjeri saying: Burndap Birrarung burndap umarkoo, meaning “What’s good for the Yarra is good for everyone.”

Sykes says: “It comes down to this [Wurundjeri] wisdom, that is: we know that these things are connected. “So the healthier the waterways are, the healthier we will be.”

Policymakers and activists trying to improve the health of the Yarra face two challenges, and they come from the same source: rainwater.

Without trash traps and “river gardens” (cultivated depressions that collect runoff and trash), rain falling on city streets carries trash and pollution into streams and rivers.

The Environment Protection Authority and Melbourne Water are measuring another drift to swimming across much of the Yarra: E.coli, the bacteria that indicates the presence of faecal pollution (mostly caused by animal faeces entering the river rather than sewage pollution).

Analysis of water samples taken over 12 years shows that E. coli levels at Kew were, on average, almost three times the recommended safe swimming threshold of 260 organisms per 100ml of water.

The agencies are testing at four water sections along the Yarra’s urban route: Warrandyte, Healesville, Launching Place and Kew. Kew consistently measures the highest E.coli concentrations of these four drugs.

But levels are marked by tides. E.coli values ​​are higher a few days after heavy downpours as rainwater washes the city’s filth into the tributaries of the Yarra and the river.

Analysis of test results shows that the highest average E.coli readings along the river occur during the warmer months when people are more likely to swim in the Yarra.

Across 12 years of data, an average of 781.09 organisms per 100 ml were recorded in January; these were the highest mean E.coli values, followed by December with 634.69 organisms per 100 ml. Both readings were much higher than the safe floating threshold of 260 organisms per 100 ml.

The cleanest section of the river was at Warrandyte, where an average of 283.43 organisms per 100ml of water was recorded (although these results were inflated by several weeks of heavy rain pushing the average upward).

Two environmental scientists from Monash University, who have spent years studying microbial levels in the river, have challenged the Yarra’s bad reputation and say it is relatively healthy for an urban river.

Senior research fellow in planetary health, Dr. Rebekah Henry says the overall health of the river as an urban system has been pretty consistent over the years.

“We use these fecal indicators because they give us an idea of ​​estimated risk. But they’re a conservative estimate of public health risk… they’re guidelines,” he says.

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Henry said tests of Yarra River water during COVID-19 lockdowns showed microbial levels remained relatively stable, a result he described as “good news”.

“No one was going out… And what was interesting was that the quality of the river remained pretty much the same throughout this period, which means what was happening in that dynamic [river] system, whether we’re outside or not, [there was] This is consistency. “I think that’s actually the good news here.”

His colleague Professor Perran Cook, who specializes in the biochemistry of aquatic environments, agrees.

“When you consider the health of the Yarra, given the size of the city, and also the geography it sits on the estuary, I don’t think you’ll find better examples of rivers in a city in terms of water quality,” he says.

“There is agriculture, there is urbanization. [And yet] You can swim in the upper parts, other than that [after] “Rainfall is too high.”

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