Environmental advocates have won a legal challenge against the federal government and mining giant Adani, over its proposed water use at its coal mine in central Queensland.

The Australian Conservative Foundation (ACF) took the Environment Minister to the Federal Court last year, arguing it made an “error of law” when it assessed the planned North Galilee Water Scheme in 2019.

The scheme proposed creating a water pipeline, pump station infrastructure and the expansion of an existing dam catchment, which would then pump water to Adani’s Carmichael mining project.

Lawyers for ACF argued the department should have applied the “water trigger” provision, which falls under the Commonwealth environment protection legislation when assessing the planned scheme.

The trigger weighs up the impacts of coal seam gas and large coal mining developments on rivers.

‘A big plumping project’

During a hearing last October, Neil Williams SC, argued the water extraction was associated with coal mining activity, and therefore the minister should have considered all adverse impacts the action would have.

Stephen Lloyd SC, who is acting for Adani Infrastructure, said because the company was a subsidiary of Adani Mining, its actions should be treated separately.

Mr Lloyd also referred to it as a “big plumbing project”, which does not seek approval to take water.

The proposed scheme would pump water to Adani’s Carmichael mine in Queensland’s Galilee Basin. Photo: ABC/Twitter/Adani Australia

“We are extracting water to be supplied to a coal miner … [mining is] not part of my client’s actions,” Mr Lloyd told the court.

On Tuesday, a Federal Court judge ruled in favour of ACF, granting a judicial review of the minister’s decision to bypass the legislation.

In her published reasons, Justice Melissa Perry said the minister’s delegate erred in his construction of definitions of sections of the relevant act and therefore “fell into legal error”.

“Contrary to the delegates view, an action will involve a large coal mining development for the purposes of the water trigger controlling provisions if the action is so closely associated with the mining of coal as to be integral to it,” she said.

Justice Perry also ordered the defendants pay the environmental group’s legal costs.

‘A great win’ for water protection

In a statement, the ACF chief executive officer Kelly O’Shanassy said it was a “great win” for the protection of water.

“It’s a win for regional communities and farmers who depend on reliable flows of river water in our drought-prone landscape,” she said.

Ms O’Shanassy said the judgement would set a “new precedent”.

“This decision will apply to other potential water sources for the Carmichael mine,” she said.

“We expect the federal government to properly apply the law.”

A spokeswoman for Bravus Mining and Resources, formerly Adani, said it would carefully consider the judgement.