The national media watchdog has found the ABC breached its own impartiality rules during a Four Corners program last year on the $5.6 billion Murray Darling Basin Plan called "Cash Splash".
The National Farmers Federation first lodged a complaint about the program through the ABC's own review channels.
When the broadcaster's independent complaint handling unit dismissed the complaint the NFF took its grievances to the Australian Communications and Media Authority.
It told ACMA the program had made no attempt to inform viewers that farmers were contractually required to transfer existing water licences to the Government for the environment in return for the grant funding.
The program had reported on the contentious issue of whether water infrastructure schemes funded under the Murray-Darling Basin Plan were providing value for taxpayer money and saving water.
An investigation by ACMA found that while it was acceptable for Four Corners to present critical commentary, the program did not present sufficient information from other relevant perspectives to enable viewers to make up their own minds about the schemes.
The national broadcaster has rejected the findings and is standing by the Four Corners team and the program.
In a detailed statement the ABC said Four Corners had spoken with dozens of people from every side of the story to gather evidence about the operation of the scheme, including a large number of former and current government insiders, farmers, irrigation engineers, earthworks contractors, senior business people in the agriculture industry, investors, water trading brokers, irrigation corporation insiders, current and former politicians, investigators, economists and scientists.
Most had declined to be interviewed on camera due to what they described as the insular nature of the industry, its close connections with bureaucracy and a culture of silence and fear within government, the irrigation industry and farming communities, the ABC statement said.
IN OTHER NEWS:
"We respectfully disagree with the ACMA's finding that the program lacked impartiality and that it should have referenced information already on the public record, or sought alternative viewpoints, when the relevant government representatives - who could have provided evidence and not just an opinion - declined to participate.
"The ABC believes this decision risks suppressing investigative or 'accountability' journalism through a distorted application of the standards under the (ABC) code (of practice)."
Meanwhile, ACMA said it had assessed impartiality by considering whether the program met obligations in the ABC code of practice 2019.
ACMA chair Nerida O'Loughlin said the ABC had failed to meet the standards in its code.
"The ABC's code of practice requires producers of ABC programs to present and report on issues in an impartial manner and this Four Corners report fell short of that," Ms O'Loughlin said.
"Although the producers of the program explored legitimate criticisms, Four Corners had a responsibility to acknowledge other perspectives on the matter of contention in a meaningful way."
The high level of public interest and debate about the recovery of environmental water under the basin plan increased the need for due impartiality in the program.
The investigation found the program omitted key information about the operation of the schemes which prevented viewers from coming to an informed understanding of the criticisms aired.
"Australian audiences expect the ABC to give proper treatment to differing perspectives when exploring controversial issues. Unfortunately, on this occasion, this did not occur."
NFF chief executive Tony Mahar said while the finding was vindication of the federation's concerns, the fact remained that hundreds of thousands of Australians had viewed the episode of Four Corners (which is still available on iview), and had as a result been misled.
"This finding has taken 12 months to get and many people have unfortunately moved on with a badly jaundiced view of the issue.
"To a mere lay person, a core tenet of journalism is presenting two sides of the story. In this case, our taxpayer funded, national broadcaster has failed miserably.
"Disturbingly, by not being impartial and by unduly favouring one perspective, the ABC has called into question the integrity and the motives of farmers who accessed the now-complete grants program.
"It's simply not good enough and the ABC needs to be held to account for the angst caused in rural and regional communities as a result.
"Remarkably a very similar finding was made about Insiders and The Drum in the Blackburn Review, made public by the Australia Senate only last week. When added to the findings in relation to another episode of Four Corners, Pumped, in 2017, a trend emerges.
"These programs are flagship and have a higher obligation to get it right but are failing,"
"We hope ACMA's findings will serve as a very strong reminder, of the ABC's obligation on behalf of all Australians to go above and beyond to present the whole story.
"We look forward to an official acknowledgement by Four Corners of ACMA's findings."