The Upper Nepean Scheme

The Upper Nepean Scheme


The Upper Canal during its construction.

It's remarkable that so little is known by Sydneysiders about such an important piece of infrastructure that once saved Sydney from drought and continues to supply water more than a century later.

The vision for the Upper Nepean Scheme was simple yet far-sighted: collect water on the Southern Highlands where it rains frequently and heavily, and transfer that water to Sydney to provide a reliable supply.

The solution that was completed in 1888 was ingenious: two weirs on the Upper Nepean rivers collect water which is sent by gravity along a series of tunnels, canals and aqueducts to a large reservoir in Sydney's west, from where it flows by gravity to the city and suburbs.

The Upper Canal

The Upper Canal today.

To get the full story read the following pages:

The Upper Nepean scheme was the first time in Australia that water would be collected far away from a city, transported by canals and pipelines, and stored in a major dam. It would also require no energy - water would simply flow by gravity.

It was a scheme of many firsts in Australian engineering and water supply history and in the commemorative publication available for download below we celebrate the remarkable achievements of those who planned, designed and built the scheme.

Barely a decade after its completion in 1888, Sydney ran dangerously low on water during the Federation drought in 1901-02.  Fortunately, the scheme's original design lent itself to progressive expansion. As Sydney's population grew from 296,000 in 1888 to nearly 1.5 million in 1939, four new dams were built on the Upper Nepean to supplement the scheme's supply.

But still today, the Upper Nepean Scheme continues to supply 20 to 40 per cent of Sydney's water.

Water continues to flow along the Upper Canal to Sydney, just as it did 130 years ago. Prospect Reservoir remains an important part of the water supply system.  And the engineers and workers who designed, built and maintained the scheme over the past 130 years continue to deserve our thanks for a job well done.

A scheme of firsts:

  • The Upper Nepean Scheme - Sydney becomes first Australian city to harvest water far from the city and transfer it by canals and pipelines, and store it in a major dam.
  • Upper Canal - unique example of nineteenth century hydraulic engineering in Australia, using canal building techniques often at very small grades, relying only on gravity.
  • Prospect Reservoir - Australia's first earth fill and rock embankment dam, and still one of the largest.


Sunday 03 July
2,614,900 ML
2,618,706 ML
8,668 ML
1,239 ML
89,916 ML
Sunday 03 July