Billionaire’s bid to build a lake in six weeks spirals into 18-month-long headache

Billionaire Mike Cannon-Brookes has long been known among Kangaloon’s genteel farming set as a staunch environmentalist and a good neighbour, the sort of local who only wants to maintain the peace and serenity of the Southern Highlands.

So it was no doubt all the more surprising for a couple of his nearest neighbours to discover that the months of noisy disruption, earthworks, and contaminated water overflows spoiling their water reservoirs and dams were coming from one of Cannon-Brookes’ farms.

The property owned by Australia’s richest environmentalist is not only under investigation by Wingecarribee Shire Council, but he has been put on notice by WaterNSW that the run-off into the Stony Gully tributary is within a legislatively protected and sensitive area in the water catchment for Nepean Dam, which feeds Greater Sydney’s major supply dams.

As neighbours lament the impact on their water reservoirs, as well as the lack of any town water supplies to this part of Kangaloon, a spokesman for Cannon-Brookes said his management team had engaged directly with neighbours to ensure all remediation will be done to a high standard.

While the spokesman said Cannon-Brookes was not aware of the planned works – or subsequent need for remediation – until recently, neighbours first heard about it in 2023 when a then-representative from the 58-hectare property, Catherine Manuel, revealed plans for a small lake with a wildlife island sanctuary in the middle.

It would be a six-week job, completed in time for Christmas 2023.

Mike Cannon-Brookes is the co-founder and chief executive of NASDAQ-listed software giant Atlassian.Credit: Louis Trerise

If the lake sounded like an expensive folly, it didn’t start as such. According to earthmoving contractor John Rodwell, the lake and island were initially part of a mitigation effort following the previous year’s record rainfalls that blew out one of the dams and left dam walls slipping.

“That area around Sugarloaf Mountain is basically sitting on an extinct volcano, and the land is all slipping,” Rodwell said. “In my experience, you need to talk to the landowners about these things.

“I wish I could have talked to Mike [Cannon-Brookes] directly, but it’s a bit like Chinese whispers; there are so many people with their fingers in the pie.”

But as Rodwell’s excavation work got under way, the solution soon became the bigger problem.

Rodwell said they had planned to move the dam up the hill. “But then we found the slip was worse than we’d thought, and I had drained half of it by the time the locals weighed in.”

As work progressed, more heavy machinery rolled onto the farm. At its peak the on-site inventory included a 30-tonne excavator rock breaker, two long-reach excavators for the mud, two heavy-duty mining dump trucks, as well as graders and rollers.

“The crazy thing about it is we’d already had two geotechnicians out, and we knew what we needed to do, but then WaterNSW and the neighbours got involved,” Rodwell said.

WaterNSW first inspected the site last November, about the same time new contractors replaced Rodwell.

Manuel is also no longer involved, having been sacked from her official role as chief financial officer of the family company Cannon-Brookes Collective last November for serious misconduct.

Malemy at Kangaloon as it was in 2021 when bought by Mike Cannon-Brookes for $8 million.Credit: Domain

Following another inspection from WaterNSW in February, an erosion and sediment control specialist has been advising on the remediation of the site. A spokesman for WaterNSW confirmed that action has been subsequently taken.

Meanwhile, work at the farm, known as Malemy, has turned from dam building to remediation and is spearheaded by the new management of the Cannon-Brookes family company led by chief executive Casey Taylor and chief financial officer Faris Cosic.

Remediation is expected to be completed later this year, said a spokesman for the Cannon-Brookes family office.

Neighbours have declined to comment publicly given concerns it might jeopardise the rectification work, but locals familiar with the site say even Cannon-Brookes’ new management has expressed shock at the extent of the damage. Manuel declined to comment for this story.

For outsiders, the extent of the damage remains visible from Orfords Road, and Google Earth reveals that the once-lush green pastureland of a few years ago is now a muddy mess of trenches and gorges.

While the challenges faced in relation to the Kangaloon property were taking place behind the scenes, Mike and Annie Cannon-Brookes’ increasingly messy separation after 13 years of marriage has been making headlines. The carve-up of their estimated combined fortune of $24.4 billion is yet to be revealed.

The estranged couple’s greater property portfolio, stretching from their $100 million estate in Point Piper to Dunk Island in Far North Queensland, has become the stuff of legend among property watchers. It totals more than $312 million based on purchase prices alone.

The cattle farm Malemy offered Cannon-Brookes more than just lush green pastures. Its southernmost boundary is a stone’s throw from Rosehill Farm, which, according to corporate records, is the registered home of Annie Cannon-Brookes.

Malemy’s purchase in late 2021 for $8 million made it one of 16 properties in the Southern Highlands acquired by the family interests since late 2016, totalling more than $116 million.

Cannon-Brookes, co-founder of the NASDAQ-listed software giant Atlassian with Scott Farquhar, remains predominantly based in the Southern Highlands at his Greyladyes Farm on Mount Gibraltar in Mittagong.

The Kangaloon land snafu comes at an awkward time for the climate-conscious billionaire.

Cannon-Brookes’ private investment company, Grok Ventures, is best known for the SunCable mega-project, which aims to build the world’s largest solar and battery complex and link it to Darwin and Singapore.

Among Grok’s other major investments is Brighte, a finance business that offers consumers affordable access to solar panels and batteries, and Cannon-Brookes’ $600 million investment in AGL Energy, which has enabled him to force the company away from fossil fuels to focus on green energy technologies.

More recently, Cannon-Brookes purchased an $80 million Bombardier 7500 private jet.

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