Farmers have rallied in the major fruit and vegetable producing centre of Shepparton as Labor and the Greens signed a new deal to keep the Murray-Darling Basin Plan afloat.
As dozens of tractors rolled through the regional Victorian town's main street, news of the deal spread from Canberra.
"Water will come out of these communities both decreasing production and hurting the communities," National Farmers' Federation president David Jochinke told AAP from Shepparton.
Changes to the Murray-Darling Basin Plan are being considered by the Senate after confirmation water recovery targets, to return water to the environment, wouldn't be met.
In a deal announced between the Greens and Labor on Monday, 450 gigalitres of water will be recovered by 2027.
Amendments also include an independent audit of water throughout the basin, and $100 million in funding for the Aboriginal Water Entitlement Program.
Holding a "keep farmers farming" placard at the rally, Mr Jochinke said the deal, which includes water buybacks, would devastate communities.
Buybacks allow the government to buy the farmers' water allocation, with the water then taken away from agriculture production.
"We are not happy that they are going to a trigger that will destroy communities," Mr Jochinke said.
"Once water has left the community, that is jobs, that is people, that is towns ... this is just a political decision."
Tony Marwood, acting chair of the Murray River Group of Councils said, said many people were "disgusted" by the deal.
"People cannot believe that there has been no consultation with rural communities," Councillor Marwood said.
Claire Miller from the NSW Irrigators' Council said the deal was "extremely disappointing."
"The government is ignoring the overwhelming opposition to its bill and more buybacks from across the basin," she said.
"Communities know exactly what more buybacks mean ... it means more job losses, it means more small businesses closing down in their main street."
Several leading Australian scientists have backed the plan.
For the past decade, Ross Thompson from the University of Canberra has studied Murray Darling river flows as part of government-funded research on how much environmental water is needed to ensure a healthy river system.
"Purchasing water is the only effective way to ensure that sufficient water is made available to meet the environmental needs of the basin in a timely way," Professor Thompson said.
Jamie Pittock from the Australian National University and the Wentworth Group of Concerned Scientists said the deal was a good start to get the Murray Darling Basin Plan back on track.
"I would like to have seen the government go a little further, for example, there's no direct action here to address the loss of water due to climate change."
He said there was no proof regional communities would lose out.
"The evidence that water buybacks will kill communities simply doesn't exist," Professor Pittock said.
Economics professor Quentin Grafton from the Australian National University also backed the deal.
The government is still negotiating with other crossbenchers to get the numbers needed for the bill to clear the upper house this week.
