Menindee Lakes

Facts and History

The Menindee Lakes system is located on the Darling River about 200 kilometres upstream of its junction with the River Murray at Wentworth. The town of Menindee is next to the lakes and Broken Hill is 110 kilometres north-west.

Menindee Lakes storage comprises four main lakes – Cawndilla, Menindee, Pamamaroo and Wetherell – and several smaller lakes with a combined capacity of 1,731,000 megalitres, three and half times the capacity of Sydney Harbour.

Lake Menindee, the largest of the lakes, is 16 kilometres long and 14 kilometres wide.

Why the lakes were developed

The lakes were originally a series of shallow natural depressions that filled during floods and then drained back into the Darling River. During drought, the lakes would dry up.

In the 1950s and 1960s the NSW Government built a series of weirs, levees and canals to capture and retain floodwaters, and regulate the release of water downstream.

A more reliable source of water was needed for domestic and mining needs in Broken Hill, and for irrigation, stock and domestic use on the lower Darling River.

Farms and orchards producing crops such as grapes, rockmelon, tomatoes and apricots utilise the water for irrigation, and when the lakes’ volume rises above 640,000 megalitres, water can be shared downstream with the River Murray under an agreement between the Australian, NSW, Victorian and South Australian governments.

The lakes are owned by the NSW Government and leased to the Murray Darling Basin Authority.

How the lakes were built

Work began in 1949 on the concrete spillway, weirs, two inlet regulators, four outlet regulators, levees and channels. Major works were completed in 1960, with final completion in 1968.

The main weir on the Darling River raises the water to 12 metres above river bed level and forms Lake Wetherell. Water can then flow under gravity, even during low flow conditions, from Lake Wetherell downstream into Lakes Pamamaroo, Menindee and Cawndilla.

Releases are made from Lake Menindee, Lake Pamamaroo and Lake Wetherell into the Darling River. A gauge downstream of Menindee at weir 32 is used to measure the total release into the lower Darling River. Releases can also be made from Lake Cawndilla for supplying environmental flows along the Great Darling Anabranch.

The lakes have a nominal full supply volume of 1,731,000 megalitres but can be surcharged above this level within certain constraints to a total volume of 2,050,000 megalitres. The combined surface area of the four lakes when full is approximately 457 square kilometres.

The lakes are very shallow and are in a hot, windy and dry area, which means evaporation is very high. The lakes lose on average about 400 gigalitres of water to evaporation every year.