Desalination of WA dam water provides irrigation relief

Posted 24 January 2017

Wellington DamThe Western Australian government has committed $37 million to help fund an innovative solution to a long standing salinity problem in the 185 GL Wellington Dam, boosting agriculture in the region and providing a new source of potable water.

A key part of the project is the diversion of high salinity water from the Collie River which will be desalinated and sold for high value potable use, providing the essential economic viability of the project.

WA Premier Colin Barnett said the resulting lower salinity Collie River water will flow into the Wellington dam and from there to irrigators through a gravity fed pipeline system.

"Taking that salt water away from Wellington Dam will mean that quite quickly, over two or three years – maybe a little longer – the salinity level in the dam will drop by more than 50%," he said.

The Wellington Dam, which is the state’s second largest water reservoir, has been decreasingly used by irrigators in the Collie River Irrigation District.  Myalup Irrigated Agriculture Precinct growers have similar problems with water quality and also supply. 

The salinity has been detrimental to the economic success of the agricultural industry in the areas, said Water Minister Mia Davies. 

The salinity effects of the water that feeds the irrigation district of Collie River are cumulatively so severe that less than 20% of the currently irrigable area of 15, 245 hectares are used productively.

"Farmers in that region are just not choosing to irrigate, or they are restricting to low-value crops."

The desalination plant would be developed under the Myalup-Wellington Water for Food project and would, once operational, sell a minimum of 10 GL a year for potable purposes.

The Western Australian government is looking for further funding in order to cover the total costs of the project, Davies said. 

"The estimated cost of the Collie Water proposal is $380 million and will require funding from the private sector and the Commonwealth Government,” she said. 

This article was amended on 3 February 2017 with assistance from Harvey Water.