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‘It’s quite unstable’, says expert of McCrae landslide site once known as Spring Hill

By Adam Carey

On Monday, Bronwyn Borghesi was in the clifftop garden of her McCrae home, surveying the Port Phillip Bay coastline below and admiring her “best bean crop ever”.

By Tuesday morning, the Borghesis’ homegrown veggie crop was at the bottom of the cliff, buried under tonnes of sodden earth that had just collapsed onto Nick and Kellie Moran’s three-storey house below.

Gerry and Bronwyn Borghesi at the bottom of the hill where a landslide destroyed the home below theirs.

Gerry and Bronwyn Borghesi at the bottom of the hill where a landslide destroyed the home below theirs.Credit: Simon Schluter

Bronwyn and Gerry Borghesi bought their home in 2014, but it has stood atop the cliff for almost a century. They have never at any stage feared it might be on unstable ground.

“Our house was built 90 years ago, further back from the cliff than most of the other houses in this area,” Bronwyn says.

“It was the only house on the whole cliff so [the builders] picked the prime position … We feel the old girl’s been there through a lot of things and hasn’t shown any signs of movement.”

But the clifftop section of the Borghesis’ property has suffered three landslips since November 2022, culminating in Tuesday’s terrifying collapse, when the Morans’ house was destroyed, another three houses were damaged and a council worker was injured. The landslide forced the indefinite evacuation of almost a dozen homes on the Borghesis’ street and in the lane below.

The landslide in McCrae happened in an area that was previously known as Spring Hill, locals say. The Borghesis’ home is top right.

The landslide in McCrae happened in an area that was previously known as Spring Hill, locals say. The Borghesis’ home is top right.Credit: Joe Armao

The Borghesis live in a part of the Mornington Peninsula that was once known as Spring Hill, locals say, owing to the many natural underground springs that flow from the summit of Arthurs Seat into the bay.

This part of McCrae, though steeply sloping, is heavily urbanised now.

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There are parts of Mornington Peninsula Shire that are covered by an erosion management overlay, a planning safeguard that is meant to “protect areas prone to erosion, landslip or other land degradation processes, by minimising land disturbance and inappropriate development”.

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But there is no such overlay on properties in McCrae, despite its long history of subterranean water flows.

David Kennedy, a professor in physical geography at the University of Melbourne, has spent 20 years studying erosion on Victoria’s coastline and says many of the houses on the McCrae hillside are built on an ancient sea cliff that is prone to erosion.

He says the area will always be vulnerable to landslides because the terrain is a mixture of hard granite and softer earth.

“It’s an area that probably shouldn’t be built on because it’s already quite steep, and it’s quite unstable.”

The hill is lined with old gullies where water has flowed towards the bay, Kennedy says. Many gullies would have been built on, forcing natural flows to find a new way to the water.

“So the question then becomes, what change have we done that has turned it from an old cliff and what would have been bush area when we developed it? I would be suspicious that there are old gullies that have been in-filled in that cliff face, and they’re going to funnel more water through.”

The Borghesis are in litigation with the Mornington Peninsula Shire Council, in two separate matters in the Building Appeals Board and the Victorian Civil and Administrative Tribunal.

The couple declined to comment on the litigation but say subterranean water movement was a well-known feature of the neighbourhood for many decades.

They say it is unreasonable to try to pin responsibility for any landslip caused by water movement on one property owner.

“It is beyond comprehension to say we are responsible, and no one has been able to explain it,” Gerry Borghesi says. “Water has run down here for a hundred years. What is the scientific and technically justified basis to say we are accountable?”

The council is investigating the source of the water that led to this week’s landslide, as is South East Water, the water corporation that services the area. Both have so far declined to comment on their investigations. The council also declined to comment on the Borghesis’ litigation.

A McCrae street damaged by underground water before Tuesday’s landslide.

A McCrae street damaged by underground water before Tuesday’s landslide.Credit: Adam Carey

Displaced residents were told at a closed-door meeting on Wednesday that a sinkhole had been located six to seven metres beneath Charlesworth Street, uphill from the landslide. It was being investigated as the potential source of the water movement that caused the landslip.

By Thursday, the investigative teams had dug a large hole in the sinkhole’s location.

Jane, a McCrae resident who did not want to reveal her surname, estimated the hole was about four metres deep. She says she observed water bubbling up from the sinkhole location onto the road in late December and alerted South East Water.

“It wasn’t just seeping. It was bubbling up through the road and coming down the gutters.”

Days later, the road burst open in two places, followed by a minor landslip near the Borghesis’ house in early January and then the major one on Tuesday.

The Morans had already been evacuated when their house was destroyed. A municipal surveyor who was inspecting their property on Tuesday was injured in the landslide and underwent surgery on his leg.

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Original URL: https://www.theage.com.au/national/victoria/it-s-quite-unstable-says-expert-of-mccrae-landslide-site-once-known-as-spring-hill-20250116-p5l4yy.html