A key part of a bold plan to transform an old mine site into a "temple to the natural world" on Victoria's coast is being questioned over its environmental sustainability.
Aluminium company Alcoa, which used to run the former open-cut coal mine in Anglesea, is set to hand over the site to UK-based social enterprise The Eden Project by 2024.
The company wants to create an environmental tourist attraction that celebrates the four elements, calling it "a love-child between the world's greatest science centre and the greatest gallery of your imagination".
The concept includes creating a 100-hectare lake from the mine pit, which Alcoa must have half-filled by Eden's deadline of 2024.
The total capacity of the pit is about 17 gigalitres (GL), more than 7,000 Olympic-sized swimming pools. It will also need another 1 GL per year to top it up due to evaporation.
Alcoa wants to source the water from an aquifer beneath Anglesea, but locals fear the way it's being done could be doing irreparable harm to the coastal town's precious ecosystem.
John McKenzie used to work as an environmental researcher for the government undertaking ecological fish surveys of the river, including the waterway's bream, gudgeons, flounder, and gobies.
"It was a magnificent system, they're all gone, they're all gone because of the acidity," Mr McKenzie said.
"We classified the river in the 70s as being one of the primary bream spawning rivers on the whole coastline, that’s how good it was, there were millions of small bream in the river."
Now, it makes him sad just to look at the river.
"Anyone with any involvement in the river couldn't help but feel ashamed of the river the way it is," he said.
Pumping going on for decades
Alcoa has been pulling water from the Upper Eastern View Formation aquifer beneath Anglesea since it first began running the mine in 1969.
It needed the water to cool down its mining equipment.
During that time, it also released about 1.5 GL back into the river system, to help increase the river's flow and balance the river's pH, or acidity levels.
In 2016, after the mine closed, the pumping of the aquifer stopped but so did the release of water back into the river.
A few years later, in 2019, pH levels in the river plummeted and have never recovered, creating a long-term environment uninhabitable for most fish species.
Streams and creeks have dried out, exposing sediment that ends up in the river usually after heavy rain, creating an acidic environment.
But exactly how much of that is attributable to the changes at the mine is a point of dispute.
Local group Friends of the Anglesea River and University of Melbourne geochemical environmental professor Ralf Haese believe the decades of pumping have reduced the flow of the river system that feeds the Anglesea River.
Alcoa declined multiple requests for an interview but issued a statement pointing to historical studies by the Department of Environment, Land, Water and Planning (DELWP) and the Corangamite Catchment Management Authority (CCMA) that point to climate change and the characteristics of the local catchment as reasons for why the Anglesea River has remained acidic.
"The river's catchments are well documented as being impacted by naturally occurring acid sulphate soil conditions," Alcoa manager Warren Sharp said.
Southern Rural Water is responsible for Alcoa's pumping licence. Its general manager Hugh Christie said there was "no direct linkage through the historic[al] evidence … of the acidity being caused by the pumping of the groundwater by Alcoa".
Friends of the Anglesea River founding member Dick O'Hanlon has been keeping a close eye on the river for a decade.
He said Barwon Water bore monitoring data showed that when pumping stopped in 2015, the aquifer's water levels recovered by about 40 metres in two years.
He said those levels dropped again by 20 metres just months after pumping resumed last year.
"The [acidity] happened very suddenly and it's not all that unusual to see the river go acidic but it normally goes back quite quickly, and it's stayed acidic since that day in 2019," he said.
Group wants rehabilitation tested
The local group is adamant it is not "anti Alcoa", but wants to see pumping stopped to allow the aquifer to refill, to check if that helps the river system recover.
"What we're really wanting to see is an Anglesea River rehabilitation plan that all of the regulators come together and identify and offer their expertise and bring together a plan that we can see the life of the river brought back brought back into its former glory," group member Janine Strachan said.
Professor Haese wrote a discussion paper on the issue detailing how the aquifer levels dropped over the 46 years Alcoa pumped from it and significantly reduced the flow of water in the surrounding ecosystem.
"The groundwater level was lowered quite significantly by 60 metres ... we now think that this lowering of the groundwater level is also affecting the local and regional swamps associated with the creeks and the catchment further upstream from the township," Professor Haese said.
"Alcoa has fully complied with the regulator, it was well known that the water extraction would lead to a lowering of the groundwater level.
"I think what was not expected is the lowering of the groundwater level has led to very severe environmental consequences."
While Professor Haese conceded he could not prove this was what happened, he believed if the aquifer was left alone to replenish, the river system would recover and fish life would return.
He also said the pumping tests being done by Alcoa were not in the correct location.
"What we are concerned about is the much shallower aquifer system that is the most important for supporting the swamps around the creeks," he said.
The group and Professor Haese have asked DELWP and South Rural Water multiple times to provide feedback on the discussion paper.
Professor Haese also said the environmental studies Alcoa references to support its stance the aquifer's levels were not connected to the river system, were outdated and did not take into account the drop in the groundwater level that continued for about a decade after those studies were published.
"Since then, the water level of the [aquifer] dropped by another 7 metres," Professor Haese said.
Abundant wetland destroyed after aquifer pumped
Locals also fear what is happening to the Anglesea River is reminiscent of the destructive pumping of water from an aquifer in south-west Victoria.
In 2019, Barwon Water was ordered by the state government to abandon plans to pump more groundwater from the Barwon Downs bore field due to major environmental damage.
Locals had been fighting for more than a decade to have the pumping stopped after noticing extreme acidity levels in rivers and swamps.
They raised $200,000 to fund independent research to prove Barwon Water's actions were wreaking havoc on the environment, leading the state government to order Barwon Water to discontinue water extraction and carry out a remediation plan.
Anglesea residents believe the Anglesea River is suffering from the same problem.
Alcoa says aquifer only option
The river group said they understood Alcoa must rehabilitate the site but wanted the water to come from the Black Rock reclamation plant in Connewarre, 35 kilometres away.
Barwon Water paid $85,000 for a report looking at potential options for using water from the plant. It found there were multiple options available but Alcoa said it would cost them up to $30 million.
Alcoa said water from the aquifer was the only option to meet the deadline of The Eden Project.
A spokesperson from The Eden Project said it was committed to filling the mine pit in an "environmentally sustainable way" but said allowing the pit to fill naturally with rainwater and groundwater infiltration would take more than 50 years "and rule out any possibility of Eden Project Anglesea".
Alcoa's current pumping test licence expires in April. An independent regulatory group will assess its findings and decide if the company should be allowed a licence to pull the 17 GL it needs to fill the pit if the company chooses to pursue that option.
