Climate change since the 1990s has drastically reduced the amount of water available in the southern part of the Murray-Darling Basin, according to new research.
- UTS research shows a big decline in the amount of water in the rivers in the southern basin
- The federal government is still committed to meeting environmental water targets through efficiency programs
- Irrigators say the target won’t be met and fear more water buybacks instead
According to the University of Technology Sydney, the height of the Murrumbidgee River has dropped by about 30 per cent during the growing season of April to May.
Report author Milton Speer said there was approximately 300 million litres less water flowing past the regional town of Wagga Wagga each day.
“Our research shows rainfall in April to May has significantly decreased, which, in turn, has caused the net inflows to the Murrumbidgee River catchment in the southern basin to decrease,” Dr Speer said.
“This includes the main dams of Burrinjuck and Blowering in the upper part of the catchment and downstream river heights.”
Inflows will continue to decrease
The Murray-Darling Basin is Australia’s biggest agricultural region, producing almost 40 per cent of the national food supply, and it is home to a range of freshwater wildlife, many of which are under threat.
Dr Speer said changes would be necessary as there was less available water to be shared around.
“The southern Murray-Darling Basin receives most of its water from rain in the cooler months that fill dams, with any overflow spilling into the floodplains.
“Continued drying and warming in Australia will cause water availability to decline even further, deepening the hurt for communities, irrigation businesses, animals and the environment.”
“There will be less and less water, and some hard decisions will need to be made, and that be probably mean less water for irrigation and farming.”
Doubt over water savings targets
The federal Water Minister Keith Pitt has been arguing that the Murray-Darling Basin Plan is on track to meet the 2024 deadline to recover water for the environment.
He is calling on the states to nominate infrastructure projects through the Off-farm Efficiency Program to generate water savings for the environment without taking water from farmers.
“There’s $1.33 billion available to fund projects that generate water savings off-farm through the state-led Off-farm stream that will count towards the 450 gigalitres of water the Basin Plan requires to deliver enhanced environmental outcomes,” Mr Pitt said.
If successful, it would increase the amount of water for the environment by 21 per cent, but there has been very little uptake of this scheme.
“Generating 450 GLs of water savings by 2024 is a tall order – but my commitment is to push as hard as we can to make our irrigation networks as efficient as possible,” he said.
Doubt over water efficiency projects
Despite the massive amount of money on the table, irrigation groups are not willing to give up more water.
Rosalie Auricht, general manager of the Renmark Irrigation Trust, said the Riverland in South Australia had already done its part when it came to water upgrades.
“We have largely piped and closed systems, so we’re delivering at around a 99 per cent delivery efficiency.”
She said the move to pipes saved about 30 per cent of the water needed for delivery and she was disappointed that the on-farm water savings program had been wound down because she felt more savings could be made in that area.
Phil Snowden from Murrumbidgee Irrigation has emphatically rejected the idea of submitting proposals to the off-farm efficiency program.
“Murray Irrigation will not be offering up more water.”
He suggested the Commonwealth Environmental Water Holder focus on delivering smaller amounts of water directly into environmental sites, as that would not require massive flows going down the river to promote flooding events.
Irrigators fear a return to water buybacks
Claire Miller, CEO of the NSW Irrigators Association, does not think the federal government will meet the deadline.
She is deeply concerned that failure to meet the deadline will trigger another round of water buybacks to make up for the shortfall.
She would rather see the federal government extend the deadline, amend the plan and change the modelling.
“All the models that spit out the numbers for recovery are based on 120 years of records, [but] the last 20 years represent a step-change.
“The answer is not to keep on buying back more water for the environment.
“We might need to consider what the rivers look like under a climate change scenario and consider our water sharing on that basis.”
And she is frustrated that new ideas and projects cannot be considered.
“There’s no way for new projects to go into the mix, so we need the Basin Plan to be amended to allow greater flexibility — new knowledge, new ideas, fresh faces.”
The UTS paper, From the 1990s Climate Change has Decreased Cool Season Catchment Precipitation Reducing River Heights in Australia’s Southern Murray-Darling Basin, is published in Nature Portfolio.