Traditional owners travel to Darwin as fight over aquifer reaches NT Supreme Court

A legal stoush over a controversial plan that could have profound implications for water allocation in the Northern Territory has reached the Supreme Court.

Lands, Planning and Environment Minister Joshua Burgoyne signed the Mataranka Water Allocation Plan, which came into effect last year.

It allows for up to 62,000 megalitres to be extracted from the Tindal Limestone Aquifer each year for the next 10 years, mostly for irrigated agriculture.

The aquifer feeds into the iconic Mataranka hot springs and Roper River — which are among the Top End's most famous tourism destinations — and is also a vital lifeline for thousands of Aboriginal people living in remote communities along the waterway.

It also supports cattle stations and, since around 2014, a nascent irrigated crop-farming industry.

Water licences had been granted prior to the plan's establishment but since it came into effect an additional 10,000-megalitre licence — to support irrigation on a new cotton, melon, mango and hay farm around Larrimah — was granted.

Before the plan was signed, existing water licence holders in the area reported only taking about 15,000 megalitres each year.

Environmentalists and Aboriginal communities are protesting the Mataranka Water Allocation Plan, but the horticultural industry has slammed their legal challenge over fears it could create investment uncertainty.

Dozens of Aboriginal people from Roper River communities travelled to Darwin, joined by Kirsty Howey of the Environment Centre NT, to watch the court proceedings on Tuesday.

"This plan is reckless, it's dangerous and it allocates far too much water from an ancient and fragile system," Dr Howey said outside court before the hearing.

"The Environment Centre is proud to be standing with communities from the Roper River, with communities from across the Northern Territory, who are saying enough is enough.

"Our water is too precious and our government should protect it."

Annabelle Daylight, a Mangarrayi woman from Jilkminggan, said it was important to ensure the next generation had access to the vital natural resource.

"It's our future — our future, our ancestors' and our great, great-grandkids'," she said.

"That's why we are fighting for our water."

Cecilia Lake, another Mangarrayi woman, said locals were "worried about our water".

"We don't want to move out of our community," she said. 

"We want to be there for the future."

Locals claim even current water extraction levels are degrading their springs and creeks, but the NT government disagrees.

The Department of Lands, Planning and Environment has consistently argued the 62,000-megalitre plan is a sustainable and conservative measure that will protect the Roper River, a claim it said was backed by data.

Adam Gaston, another Jilkminggan resident, said he wanted to see a decision that created "positive outcomes for our country".

"Save our water and our people," he said.

Complex questions of law

Both sides have agreed that the NT Supreme Court dispute centres on technical matters of law and process.

As the plaintiff, Environment Centre NT wants the plan to be axed because it was not made in accordance with the NT's Water Act.

It argued Mr Burgoyne was responsible for allocating enough resources to maintain groundwater-dependent ecosystems such as Mataranka's unique palm forests around the hot springs.

But the plan he signed only allocated a very small amount of the 62,000 megalitres — 30 megalitres — for the environment.

The Mataranka Water Allocation Plan, however, goes on to describe that figure as "nominal" and says the "majority of water is already retained in the environment".

In other words the rest of the water in the system goes to the environment by default — but a lawyer representing the Environment Centre NT, Peter Willis SC, said that was not good enough.

"That water is left unprotected, uncontrolled, at the mercy of licensing decisions down the track," the barrister said.

But the defence argued Mr Burgoyne's plan had already "substantially achieved" the objective of protecting ecosystems.

His barrister, Lachlan Spargo-Peattie, said the 62,000 megalitres outlined in the plan was "conservative" and argued the minister had acted within his discretion in approving it.

Justice Jenny Blokland will consider the evidence given at Tuesday's hearing, as well as substantial volumes of written material.

Her decision is expected to take some time.

Environment Centre NT said a win in the case could have substantial flow-on effects for other water plans in the territory.

Ms Howey said even if the case failed, advocates would continue protesting against increasing extraction from the aquifer.