Burrinjuck Dam

Facts and History

Burrinjuck Dam is situated near the headwaters of the Murrumbidgee River in the Great Dividing Range. It is about 55 kilometres south-west of Yass, and about 330 kilometres south-west of Sydney.

Burrinjuck Dam is the main water storage for the Murrumbidgee Irrigation Scheme, a 660,000 hectare area in the Riverina irrigated with a series of weirs, canals and holding ponds. The dam has a capacity of 1,026,000 megalitres, twice the volume of Sydney Harbour.

The name Burrinjuck comes from the Aboriginal words ‘booren yiack’, meaning precipitous mountain. The dam is appropriately named as it lies between the Barren Jack and Black Andrew mountains.

Why the dam was built

In 1891 the Murrumbidgee Valley was identified as being ideal for irrigation development. After devastating droughts in 1901-02, the NSW Parliament approved the establishment of the Murrumbidgee Irrigation Area Scheme to control and divert the flow of local river systems for the purpose of food production.

Burrinjuck was the first major dam built for irrigation in NSW. When construction began in 1909, it was the fourth largest dam in the world. Construction delays due to World War I meant the original design was not completed until 1928.

Burrinjuck releases water for irrigation of crops in the Murrumbidgee Irrigation Area, including cotton and fruit and vegetables, as well as pastures for sheep and cattle.

In addition to irrigated agriculture, the dam provides water for town supplies, industry and domestic requirements, environmental flows, flood mitigation and recreation, and a 28 megawatt hydroelectric power station using irrigation releases, environmental flows and flood mitigation.

How the dam was built

Burrinjuck Dam was built in a narrow gorge on the Murrumbidgee River. The steep gorge required the erection of a cableway across the spillway face to ferry workers and materials from one side to the other. Building materials were delivered to the site by a wood-burning locomotive travelling on a narrow gauge railway line built for the project, connecting the construction site to the main southern line at Goondah, south of Yass, 42 kilometres away.

Burrinjuck is a mass gravity dam which holds back water by using its own weight. The wall was built using cyclopean masonry with giant concrete blocks fitted into an irregular pattern. Granite quarried on the site was mixed with sand barged from up river and cement transported by rail. Each block contains a giant granite boulder, weighing on average four to five tons.

Work started in 1909 but was not completed for 20 years due to World War I and labour shortages. Hundreds of workers lived on-site at ‘Burrinjuck City’ in barracks provided for single men. They used steam engines and manual labour to build the massive wall.

Following a big flood in 1925 that sent water pouring more than a metre over the wall, it became clear the height of the wall and size of the spillways had to be increased. These enlargement works continued for another 20 years between 1937 and 1956, again interrupted by war.

Later improvements

To meet modern dam safety standards and increase dam safety in the event of extreme flooding, between 1986 and 1994 the wall was strengthened by post-tensioned anchors, the dam’s spillways were upgraded and the wall was raised by 13.4 metres to its current height of 92.4 metres.