Burst water main possible cause for Penny Lane, McCrae landslide

A burst water main has been identified as a potential factor behind a Mornington Peninsula landslide in which a three storey home was destroyed

Update, Wednesday afternoon: A burst water main has been identified as a potential factor behind a Mornington Peninsula landslide in which a home was destroyed.

Senior counsel assisting the board Mark Costello KC said too much water in the soil was the most likely potential cause being investigated, with a burst main near the Mornington Peninsula Freeway one theory.

“The thesis is that water leaking from a water main located south of the Mornington Peninsula Freeway could have travelled through the storm water system and trenches surrounding local water infrastructure all the way to the escarpment,” he said.

Before and after images of the January 14 McCrae landslide. Picture: Supplied

“Excess water was observed in McCrae both before and after the landslide.

“From mid-November local residents observed excess water near Penny Lane … the water emerged through the roads, it pushed up and cracked the asphalt, it created potholes, flowed down the streets, saturated nature strips and leaked into the kerbs.

“Shortly after the landslide on January 5, water was seen flowing out of the escarpment above the Morans’ property. The flow of water was constant and continued to flow on the day of January 14 and weeks thereafter.”

Inquiries made about the excess water by a group of evacuated residents led them to the water main pipe near the freeway.

“It revealed significant signs of saturation (near the burst main), trees fallen over and sandy top soil had been washed out,” Mr Costello said.

“There does not appear to be any doubt that the water main had burst or that South-East Water had acted to repair on or about New Year’s Eve.”

In the months that followed the repairs the excess water had dried up.

Other “avenues” being explored include building works, vegetation removal, adequacy of stormwater diversion and natural springs.

The inquiry continues.

Earlier, Wednesday morning

Residents impacted by a Mornington Peninsula landslide in which a home was destroyed will give evidence at a public inquiry into the disaster, which the chair hopes to get to the bottom of “quickly”.

The review into the cause of the January 14 McCrae landslide — where a luxury home had its second and third levels knocked over and a council worker was hospitalised after having to jump from the tumbling house — commenced on Wednesday.

The three-storey, four bedroom home, at Penny Lane above Point Nepean Rd owned by Nick and Kellie Moran, fell about 50m from above.

Residents from 19 properties were also forced to evacuate, with many still stuck in limbo and unable to return due to the area becoming part of a growing exclusion zone.

Eight houses still remain off limits to residents.

The home fell about 50m. Picture: Ian Currie

Inquiry chair Renée Enbom KC said she was determined to find answers “quickly”.

“I’m determined to make recommendations as quickly as possible to prevent or mitigate risks of other landslides,” she said.

“Those residents who have not returned home must do so safely.

“This inquiry is not an opportunity for grandstanding or litigation type strategy … it’s about finding answers in the public interest.”

A council worker had to jump from the home as it fell. Picture: Wayne Taylor

Earlier this year council said it expected to spend about $8m on the disaster, costing every Mornington Peninsula resident about $75 each.

More than 30 public submissions for the inquiry were made by residents, some of whom will provide evidence next week about how they were impacted.

Some homes are still off limits, months later. Picture: Ian Currie

The inquiry heard there had been a previous landslip on January 5 as well as two on Viewpoint Rd on November 14 and 15 in 2022.

The January 5 event caused damage to the same home – owned by the Morans – that fell down the cliff nine days later.

The inquiry heard the property sustained structural damage after about 25 tonnes of materials struck the house.

Ms Moran and her daughter were inside the house at the time of the January 5 landslide.

The inquiry heard there had been no rain in the lead up to the January 5 landslide and only “moderate” rainfall in the week before the second.

It comes as about 80mm of rain fell in the area before the 2022 disasters.

Five homes were evacuated after the second 2022 landslide on November 15.

Some residents impacted by the 2022 events have still not been able to return home.

In 1952, a landslide near Anthony’s Nose — about 2km from McCrae — destroyed eight homes which was caused by significant rainfall.

The inquiry will also hear from several witnesses, including engineers and Mornington Shire Council employees.

A final report to be presented to the state government by June 18.

Originally published as Burst water main possible cause for Penny Lane, McCrae landslide