A leading Victorian water broker says permanent changes to the Goulburn-Murray River intervalley trading rules will have an impact on both allocation and entitlement markets.
Bendigo-based H20X Business Development manager Craig Feuerherdt said the interim rules were being "cemented" into the Victorian Water Act.
"It is a significant decline in the volume of water that moves out of the Goulburn and - more importantly - into the Murray," Mr Feuerherdt said.
"In the last few years, we have had upwards of 200GL being able to be transferred out, in the dry years it's been up to 400GL.
"Let's say it's halving it - that just creates more demand stress, in the Murray."
The state government made temporary trading rules permanent, from July 1, after concerns about bank erosion in the Goulburn.
But it comes as it is getting harder to get water through the Barmah Choke, on the Murray River.
The Goulburn is below the Choke.
Under the permanent rules, the Goulburn Intervalley Trade (IVT) will reset on July 1, every year, irrespective of the balance on June 30.
In a fact sheet, H20X said there would be three explicit trade openings during the season.
- On July 1, 85GL, which H20X regarded as a conservative volume of trade opportunities.
- In mid-October and mid-December, volumes of 0-55GL will be available, dependent on actual water use in the Torrumbarry irrigation district.
- Trade remains capped between December 16 and June 30.
H20X found the larger trade volumes, in fewer announcements, would allow more participants to trade.
The rules also maximised trade opportunity, each season.
"This, in turn, maintains flexibility in river operations without unnecessarily restricting trade," the broker found.
Trade was also based on real water usage in the Torrumbarry district, providing flexibility in drier seasons.
Mr Feuerherdt said when it was dry, less water was available from NSW.
"Supply constraints (through the Choke), now these trading constraints, will create another pinch in the market," he said.
"When water was trading in the Murray at $1000 a megalitre a few years ago, the Goulburn was maybe $300-400/ML cheaper.
'You are going to see massive variances there - the price differential will be way larger."
He said the decision could be "spun any way you want.
"Yes, we are looking after the lower Goulburn, yes we are protecting Goulburn irrigators from extreme prices, because there will be more water, but we are throwing the Murray irrigators to the wolves, basically," he said.
In its fact sheet, H20X said the opening balance, on July 1, had always been hotly contested.
"The 40GL available on July 1, 2021, was taken up in 20 minutes," the fact sheet said.
But Victorian Farmers Federation Water Council chair and Murrabit irrigator Andrew Leahy said the new rules were a compromise.
"From a VFF point of view, we have members, downstream, in Lower Murray, who are pretty keen to have it opened up," Mr Leahy said.
"We have members in the Goulburn area, who are pretty keen to shut it up, and the environment who are pretty keen to lower the flows in the river.
"Everyone has taken a little bit of a hit, it's been a compromise on a river that's been degraded by running too much water down it."
Mr Leahy said there would be more water locked into zone 1a, the Goulburn, Pyramid Hill, Boort and Rochester district.
"If you are a seller, you are probably not that pleased," he said.
"Overall I think it's okay, I'm not saying it's good, but I am not jumping for joy."
Meanwhile, there's been relief for irrigators in the Numurkah area, who feared hundreds of thousands of dollars of infrastructure upgrades were in jeopardy if proposed changes to water take on the Lower Broken Creek went ahead.
Read more: Further talks on Broken Creek tag system
The current rules have been left as they were,with an an exemption for tagged water use restrictions for the creek, while trade and water use behaviours are monitored over the next four years.
It was a decision welcomed by Kaarimba dairy farmer Mark Bryant who was part of the Department of Environment, Land, Water and Planning consultative group, formed to find solutions.
"I would have said it was as much because of COVID that they couldn't get out and have discussions on the Creek, really," Mr Bryant said.
"I think it was in a bit of a "too hard" basket and they needed a bit more time to resolve it.
"Irrigators were saying "how are you going to grow your farm, if they authorities keep changing the rules every year."
He agreed certainty around water access was paramount.