The Warragamba River had two important advantages as a site for a major dam. It had a large catchment area and the river flowed through a long and narrow gorge. The government could build a tall and narrow dam that could impound a vast amount of water.
Its potential was identified as early as 1845, but plans were deferred while the Upper Nepean dams were built between 1907 and 1935. An increasing demand for water from the expanding population, and a record drought from 1934 to 1942, forced the the government to develop Warragamba Dam to ensure a reliable water supply.
Constructed between 1948 and 1960, Warragamba Dam was a major engineering feat of the mid 20th Century. Workers removed more than 2,300,000 tonnes of sandstone from the site.
Concrete was mixed on site using 305,000 tonnes of cement and 2,500,000 tonnes of sand and gravel.
The dam was built in a series of interlocking concrete blocks. A system of overhead cableways lifting 18 tonne buckets was used to place the concrete.
Ice was mixed with the concrete to control the heat generated by the setting concrete and to prevent cracks forming. One of the first pre-
Warragamba Dam was designed as Sydney's main water storage dam -
Warragamba Dam is not a flood mitigation dam and can only mitigate floods to a limited extent. If partly empty before any flood, it can store the incoming floodwaters. When full, it slows the release of floodwaters into downstream areas. In the 1961 flood -
Heavy rain falling in the catchment area can overfill the dam. The dam gates begin to open gradually when the water reaches 80 millimetres above the full storage level by first the central drum gate gradually opening automatically, and if water continues rising, the four radial gates start opening at 23 centimetres above full storage level. The progressive gates help control the flow of water. They are rarely opened manually.
The dam forms Lake Burragorang and is filled by run-
Between 1987 and 1989 the dam wall was raised by 5 metres and strengthened using post-
To protect the dam in times of extreme floods in the catchment area, an auxiliary spillway was built on the east bank of the dam. This was completed in June 2002.
Distance & direction from Sydney: 70 Klms E
Farnsworth Avenue, Warragamba
Tel: 1300 722 468
Height: 142 metres
Length: 351 metres
Thickness at base: 104 metres
Width of central spillway: 94.5 metres
Volume of concrete: 3 million tonnes
Width of auxiliary spillway (at mouth): 190 metres
Length of auxiliary spillway: 700 metres
Capacity: 2,031,000 megalitres
Area: 75 square kilometres
Length of lake: 52 kilometres
Length of foreshores: 354 kilometres
Maximum depth: 105 metres
Area: 9,051 square kilometres
Average annual rainfall: 840 millimetres