Water supply history
Australia is one of the driest continents on earth. Water has been vital to the survival and prosperity of Sydney since the first days of the new colony. The need to ensure a reliable water supply through times of drought and erratic seasonal rainfalls has driven the development of several complex and innovative water supply schemes.
Sydney's original water supply came from Tank Stream named for the 'tanks' or reservoirs cut into its sides to save water. The stream, which wound its way through the colony before emptying into Sydney Harbour at Circular Quay, degenerated into an open sewer and was abandoned in 1826.
Convict labour then developed Busby's Bore, a four kilometre tunnel leading from the Lachlan Swamps, (now Centennial Park) and ending in the south eastern corner of Hyde Park.
Botany Swamps Scheme
By 1852 drought and increasing population led to the call for a more permanent water supply for Sydney. A third water source, the Botany Swamps Scheme, began operations in late 1859 but within 20 years, the once copious supply of fresh water was depleted.
Upper Nepean Scheme
The innovative Upper Nepean Scheme was Sydney's fourth source of water supply. Completed in 1888, the scheme diverted water from the Cataract, Cordeaux, Avon and Nepean rivers to Prospect Reservoir via 64 kilometres of tunnels, canals and aqueducts known collectively as the Upper Canal.
However, the Upper Nepean Scheme bought only temporary relief to Sydney's water supply woes. The drought of 1901-1902 brought Sydney periously close to a complete water famine. After two Royal Commissions into Sydney's water supply, the authorities agreed that a dam be built on Cataract River. The successive building of Cataract, Cordeaux, Avon and Nepean dams between 1907 and 1935 greatly improved the Upper Nepean Scheme's capacity.
Blue Mountains dams
Further afield, construction of the six dams that serve the Blue Mountains region commenced in 1905 with the construcion of Cascade Dam No. 1 in 1905 - to the building of Greaves Creek Dam in 1942.
Supplying Sydney's south
Meanwhile, a scheme to supply water from the Woronora River to Sutherland and Cronulla in Sydney's south was resurrected. Construction of Woronora Dam began in 1927 and was completed in 1941.
The potential of Warragamba as an important site for a major dam was identified as early as 1845, but plans were deferred during the construction of the Upper Nepean dams. An increasing demand for water, combined with a record drought from 1934 to 1942, forced the development of Warragamba Dam to ensure a reliable water supply. Construction of Warragamba Dam commenced in 1948 and was completed in 1960.
The Shoalhaven Scheme
The plan to develop a water supply system in the Shoalhaven first rose during the end of World War One. It was not until several decades later, in 1968, that the then Water Board consulted the Snowy Mountains Hydro-Electric Authority about the longer term water needs of Sydney and the south coast. There was concern that Warragamba Dam, which had opened only eight years earlier, might prove inadequate to meet Sydney's water supply needs by the mid 1970s.
The advice was to proceed with the Shoalhaven Scheme - situated in the lower Shoalhaven River and Kangaroo Valley areas - on the coastal range above Fitzroy Falls and on the Upper Wingecarribee River. Construction began in 1971 and was carried out by contractors under the supervision of the Snowy Mountains Engineering Corporation. The Scheme was completed in 1977 at a final cost of $128 million.