Formed millions of years ago and hidden from sight, Australia's precious underground water is becoming a new battleground in the fight for water.

As surface water becomes more scarce and more expensive the value of groundwater is increasing.

And big corporations are among those trying to cash in on it.

In farming country just north of Shepparton in northern Victoria, multi-million dollar agricultural investment corporation goFarm is buying up properties all over the district.

Documents obtained by the ABC from The Weekly Times show the company wants to control at least half of the Katunga Deep Lead Aquifer, an important groundwater resource for local farmers.

There is no limit to how much water one company can control and the acquisition of large volumes of groundwater licences has many concerned the resource isn't being adequately protected.

Big corporations are looking to cash in on Katunga's water supply. ( ABC News: Peter Healy )

Family farms sell up

It comes as tensions across the country are erupting over the skyrocketing price of water and anger over water mismanagement, exacerbated by the ongoing drought.

Farmers at Katunga in the Goulburn Valley, who are desperate to get out, struggled to sell their land until the arrival of corporate investors with deep pockets and a plan to control water.

Yarroweyah farmer Bill Jones sold his farm along with the surface and Katunga bore water rights to goFarm in January.

"To me, I couldn't see a future," Mr Jones said.

"Drought's caused a lot of it, but total mismanagement and total utilisation of the water is basically what happened."

Bill Jones is happy to be out of the dairy industry but fears for the future of his community. ( ABC News: Jess Davis )

The immense pressure on the dairy industry and the water crisis impacting across the country has resulted in a mass exodus of family farmers from this region.

Many locals, including stock agent Sam Nelson, are worried.

"There's certainly no transparency about what's going on and it's making the area inaccessible for the person who wants to come and be a genuine primary producer," he said.

"What concerns me is what's driving them — is it to buy the water to secure the water, so it becomes less available to others?"

Sam Nelson has sold 10,000-plus dairy cows in less than a year for people leaving the industry. ( ABC News: Jess Davis )

Who owns the water?

GoFarm is an Australian-owned agricultural investment manager, with investments in almonds, irrigated crops and vineyards.

The company is using its Akuna Trust to buy property with access to the Katunga aquifer and aims to invest more than $100 million in developable land with 'below-the-ground water assets'.

They say they want to create a 'scarcity premium' when it comes to groundwater.

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As of February, the Akuna Trust owned more than 17 per cent of the Katunga deep lead aquifer and 3,000 hectares of land.

In a statement to the ABC, goFarm said it planned to move to high-margin, high-value produce.

"Our investment in the district and intended strategy for our properties will result in the irrigation water being retained and productively used," goFarm said.

"To us, this inevitably means fruit and nut crops."

An industry downturn and high water prices have led to an exodus of dairy farmers in Victoria. ( ABC News: Jess Davis )

Tree nuts such as almonds have expanded rapidly in recent years, with an estimated 12,000 hectares of new trees planted between 2016 and 2018.

It's a much more lucrative industry than dairy, but also a significant drain on water resources, and irrigators are concerned about the long-term sustainability of the cash crop.

Thousands of years to replenish

Over the past 10 years, farmers in this area have only used about half of the groundwater allocation, but as big companies like goFarm move in, it's likely that will increase.

Scientists are concerned that regulations and management plans aren't sufficiently set up to protect groundwater.

Records show the Katunga groundwater levels have been declining since the 1990s.

RMIT hydrogeologist Matthew Currell said the long-term impacts of increasing water usage might not be known for decades.

"Most of the aquifer is not able to receive immediate recharge when it rains," Associate Professor Currell said.

"The sort of time scales for replenishment of water in that system is in the thousands of years, even up to tens of thousands of years."

While management plans adapt year on year, depending on the amount of water taken out, Associate Professor Currell said a rapid change could result in long-lasting damage.

"The rules haven't been created, they're not designed for situations where very, very large licence holders can use a dominant position essentially to squeeze other water users in the area."

Immense industry pressure and the water crisis have resulted in family farmers leaving. ( ABC News: Jess Davis )

Community unrest

The lack of transparency and fears of corporate control in the region are stirring up anxieties among locals at Katunga.

Water policy expert Rebecca Nelson, from the University of Melbourne Law School, said communities could be left in the dark about what was going on beneath their feet.

"For a critical resource that people rely on during drought and that will become even more important in the future — a critical resource that's hidden — arguably there's need for a bit more transparency there," she said.

"I think were the community to be involved more deeply with water management, one would hope that that would give the community confidence that the resource is being managed sustainably."

In Victoria, regulations governing groundwater mean there is no easy way to find out who owns water and what they are doing with it.

Water is the talk of the town in northern Victoria. ( ABC News: Jess Davis )

Local water authority Goulburn Murray Water told the ABC it was 'unable to release individual licence details due to commercial privacy reasons'.

"That's the way they [goFarm] like it, so that nobody knows what's going on; it's just the way they work, they're a private company," said former farmer Bill Jones.

GoFarm did not address the ABC's questions relating to concerns about transparency and one company controlling so much of the aquifer.

Policy lagging behind

Anger over water prices has led to crisis meetings along the Murray-Darling Basin. ( ABC Landline: Tim Lee )

State member for Shepparton Suzzana Sheed said not a day went by that she did not hear about the issue.

"What's happening in our communities is really concerning, not just to me but to everyone. There's almost a feeling of helplessness sometimes around what water policy has done," she said.

"There are issues that we don't know and understand probably sufficiently about groundwater yet."

The Victorian Government announced a review of water transparency last month.

In a statement to the ABC, a government spokesman said the review would include groundwater markets to ensure community and water sector confidence.

"There is a rigorous process in place for the ongoing monitoring of groundwater levels across the state to ensure we are balancing the needs of the environment, domestic and stock users, irrigated agriculture, commercial users and urban communities."