The Darling River Action Group Incorporated (DRAG) was formed in 2004 after Broken Hill’s water supply turned salty and foul in 2003 and came very close to drying up. The water came from the Darling River and it became clear to Broken Hill’s citizens that the security of their water supply depends on the health of the Darling River and the Menindee Lakes.
DRAG’s aim is to improve the health of the Darling River in terms of water flow, water quality and riverside environment. The group has members and supporters in Broken Hill, Menindee, Wilcannia, other parts of Australia, as well as a few international members.
DARLING RIVER ISSUES
The Darling River is being starved of water, and it in turn is starving the Murray River of the flows it once delivered. The Darling River has always had periods of no-flow, but now a zero flow is the normal state.
The catchment of the Murray has been in a severe drought, but not so the Darling catchment. Bureau of Meteorology maps show that for the two years between October 2007 and September 2009, rainfall over the whole Darling catchment has ranged from average to very much above average. But water flows down the Darling have dropped right off, and Menindee Lakes are down to much less than 20 percent.
Where has the water gone? Average annual runoff into the rivers of the Darling Basin is about 7,000 gigalitres. In 1960, about 50 gigalitres were extracted for irrigation. By 1990-91, this extraction had increased to 1,400 gigalitres. By 2007, the total annual surface water used in the Darling Basin was about 3,200 gigalitres (State of the Darling Report 2007 – Webb, McKeown & Associates Pty Ltd). Most of this increase in water extraction is due to expansion of the cotton industry. Cotton growers pump water from the rivers and store it in large, shallow dams known as ring tanks. The water sits in these tanks evaporating until the cotton growing season starts. Each summer, cotton fields are flooded several times to saturate the soil. None of that water can be returned to the rivers, because it contains undesirable chemicals and salt.
Some of the chemicals are nitrogen-rich and phosphorus-rich fertilisers. When these enter the rivers they promote algal blooms. In the summer of 1991-2, the Darling River experienced a world record bloom of poisonous blue-green algae, extending 1,000 km from Mungindi to Wilcannia.
Salt is a problem for the entire Murray-Darling Basin. Traces of sea-salt constantly blow into the Murray-Darling Basin dissolved in rain. Salty groundwater from springs empties into the Darling at low water levels. The rain washes salt from the land into the rivers. The only way that this salt can escape from the Basin’s waterways is via the Murray River mouth at Goolwa in South Australia.
With reasonable flows, the Murray River takes 20 million tonnes of salt out to sea each year. Now the Murray River does not even reach the sea without assistance from constant dredging, and all of the salt remains in the Basin. The river system is dying from the bottom up.
There is only one remedy for the problems of the Darling River system – extract less water. There are a number of ways in which this can occur, and some progress has been made.
The Commonwealth Government’s wholesale buyback of water licences from a number of large cotton irrigation properties will make a significant difference when flows occur. Already their buyback of Toorale Station below Bourke allowed about 12 gigalitres extra to flow down the Darling River in the following flow. The purchase of the 240 gigalitre water licence from the Twynam Company will boost this.
More recently there have been proposals to improve the efficiency of existing irrigation works, and hopefully to put some of the saved water back into the rivers.
Water has been purchased to permit a massive bird-breeding event at the Narran Lakes and to help restore the Macquarie Marshes. The NSW Government has prohibited new works designed to collect overland flow.
The Darling River Action Group want to see the Darling River restored to health. For more information see
Darling River Action Group