Old Sydney Tank Stream, Picture courtesy of NSW State Library
Everyone is familiar with Sydney CBD but very few actually know about the history buried beneath the city. Still in existence today is the Tank Stream, Sydney's first main source of fresh water supply during the early colonial settlement period.
Once there was a swamp stretching from Hyde Park to Town Hall supplying fresh water into the stream, which flowed 30 metres down a series of waterfalls to modern day Bridge Street before discharging into Sydney Cove (Circular Quay).
You can now appreciate the sloping topography in which the stream once cascaded down towards Circular Quay from Hyde Park.
Old Sydney Cove, Port Jackson - Picture courtesy of the NSW State Library
In 1788, Captain Arthur Philip sailed into Sydney Harbour and found a stream flowing out into Sydney Cove. He declared that it was the 'finest spring water' and made settlement for the colony.
The name 'Tank Stream' came from the excavation of storage tanks in the surrounding sandstone (near Australia Square) to supplement the growing demand for water.
By 1826, the Tank Stream became so polluted it was turned into an open sewer causing an outbreak in water borne diseases. In 1958, the authorities diverted the stream and hid it from public view. Eventually, the whole stream got buried underneath the growing city. In 1930, it became part of the city's stormwater drainage system carrying flows from lower CBD to the harbour.
The Tank Stream was recognised for its state and national significance and was registered on the NSW State Heritage Register in 1999.
The Tank Stream tour was established soon after and is operated by Sydney Water. On the day of the tour, you will see Sydney Water's vehicles parked on Curtin Street opposite Australia Square.
Sydney Water Tank Stream Tour, Curtin Place (outside Australia Square)
The tour guide will take you inside Australia Square's basement into a small chamber where you will view a short video presentation of the history of the Tank Stream. You will then be given a safety briefing and get fitted with a hard hat, boots and a safety harness to help you down the narrow 3 metres-deep shaft.
Once inside the Tank Stream tunnel, you will notice the sandstone block construction with a low arched ceiling (half an average person's height) so, expect to hunch for most part of the tour.
The tunnel itself has an earthy smell and is surprisingly clean, and if you are lucky you will witness the flowing stream and its crystal clear water.
I did this amazing tour in 2010. It is open to the public only twice a year, one in April and either October/November. If you are interested, it is by ballot and it is very popular. Please register your interest via The Historic Houses Trust of NSW