Warragamba Dam is the primary water source for the Australian city of Sydney, New South Wales. It also connects with the Hawkesbury River and Nepean River. It is approximately 65 kilometres (40 mi) to the west of Sydney on the Warragamba River, a tributary of the Hawkesbury River, and impounds Lake Burragorang.
The Warragamba River flows through a gorge that varies in width from 300 metres (980 ft) to 600 metres (2,000 ft), and is 100 metres (330 ft) in depth. This gorge opens out, at the upper end, into a large valley, the Burragorang Valley. This river configuration allows a relatively short but high dam wall in the gorge to impound a vast quantity of water.