Melbourne sewer construction, 1890s

Roderick Smith

'It’s incredible': The old engineering wonder buried beneath Melbourne 9 July 2018.

The crane groans and shudders as it hauls up the cage from the depths of a deep black hole not far from the banks of the Yarra River.

Eventually, the grimy faces of workmen appear.

"What does it smell like?" one of the onlookers gathered around edge of the hole asks.

"Like shit," they reply together.

Workers are excavating one of Melbourne's first ever sewerage systems. Pictured are Brad Newman and Shane Newman from John Holland KBR. Photo: Darrian Traynor Spotlights are pushed over the edges of the huge manhole, providing a view of the depths.

The light plays off brick walls which are stained black. Small pipes jut out of the walls on all sides, adding their trickles to the flood of human waste that rushes like a river 13 metres below.

This duct, in Spotswood, was built as a key upgrade to Melbourne’s first sewer system around 1930. It was made by unskilled workmen who dug into the city's swamp with spades and dodged deadly methane explosions.

It has performed flawlessly for the last century. When maintenance workers chain-sawed it open last month they discovered it was in almost-perfect condition.

"It’s incredible. It’s a marvel of engineering," says Tom Ryan, who manages the project for Melbourne Water.

A 1892 map of Melbourne's sewers. Most of the infrastructure remains in place. Photo: Melbourne Water / Supplied.

Modern Melbourne’s skyscrapers are built on an old engineering wonder, buried deep in the soil. More than 400 kilometres of pipe, much of it built by hand more than 100 years ago, sits under the surface, connecting millions of homes.

Before it was built, Melburnians had no choice but to dump their raw sewage in the streets, and the city was choked with lethal typhoid.

This image, taken sometime between 1893 and 1897 of a sewer pipe nearby, shows the original brick construction methods. Photo: Melbourne Water / Supplied But sometimes the old ways are better. In the 1960s, sewer construction methods changed from brick to modern concrete. "We found ironically the earlier sewers built in brick are standing up better than the later ones built in concrete," says Mr Ryan.

And the pipes were built with heaps of extra capacity, so despite Melbourne’s population growing from perhaps half a million to 4.9 million, producing about 900 million litres of excrement a day, the sewers are far from choked.

In fact, this duct has only been opened so crews can inspect and reline the channels with plastic pipe to protect them from any future damage. It's part of a huge Melbourne Water project to reline more than 100 kilometres of the city's sewers.

This image shows the 12-tonne gates - known as penstocks - and below, the rushing torrent of sewerage. Photo: Darrian Traynor About 20 per cent of the city’s sewage flows through this 13-metre black hole. Back when it was built, huge steam engines would have been connected here to move the 12-tonne steel sewer gates that control flow.

But that system fell apart years ago and now they are permanently locked open.

The workers will cut them out with a super-high-pressure 'water laser' before removing them.

Building a sewer network by hand and steam-power was a dirty, dangerous job.  Photo: Melbourne Water / Supplied When this duct was built, the workmen managed to blow one of the huge gates right off. Bacteria love sewers, consuming faeces and releasing methane and other flammable gases. "They had no gas detectors back in the day, and they did not fully understand the consequences of these gases," says Mr Ryan.

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Methane apparently built up behind one of the gates, and a naked flame – a candle, maybe – ignited it, blowing the 12-tonne gate right off. Miraculously, nobody was hurt.

After the lining is done, the workmen will close up the duct again.

All going as it should, they won’t need to open it again for another 100 years.


* And some in this country would have you believe that the expense undertaken to creat this marvel is little more than intergenerational theft.

* Amazing. Looks similar to those built in Paris and London, but we hear less of our sewage system, even though it is a great engineering feat.

* Once we had Governments and organisations like the Board of Works that actually planed for the future. Today leadership in Victoria and Asutralia is rife with mediocrity. Could not plan the proverbial booze up in a brewery. Soon we will  be faced with elections where we will be asked to select which group of mediocre candidates we want to run Victoria and Australia further into the ground.

* Back in those days, things were built to work, and built to work long into the future; cost was secondary. These days, cost is primary; things are built to the bare minimum standard that will work, and only for as long as any mandated warranty.

* The longevity of Melbourne's sewers is pretty good, but remember that the mother of all sewers, Rome's cloaca maxima, is still going strong after more than 2000 years! Now that is future proofing.

* A reminder of the enormous benefits to human health and welfare that have been brought to us by engineering.

* Is this the work that's being done along Douglas Pde Newport/Willi. for the past few months?

* Amazing foresight! We can't even build a freeway these days without it being choked to the sh*t after 5 years.

* Back in the day engineering works were built to LAST unlike today build / demolish / build / demolish all for profit greed and political point scoring.

[LRRSA 'Light Railways' has had a good article on the railways used to support the original construction.  In later years, railways were used for the construction of new main-trunk sewers, with depots at East Malvern and Laverton].

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