Excess water flowed through the streets of an affluent Mornington Peninsula neighborhood for weeks before a catastrophic landslide destroyed a luxury holiday home, an inquiry has heard.
The January 14 disaster, which led to the collapse of the multimillion-dollar property, also resulted in severe injuries to a council worker and forced multiple evacuations. The event raised serious concerns about the safety of nearby homes.
Residents in eight hillside properties are still awaiting clearance to return. Geotechnical experts, local residents, and authorities are scheduled to testify at an inquiry that started today in Melbourne.
During the opening address, counsel assisting Mark Costello highlighted one line of investigation: whether a significant water leak might have saturated the escarpment beneath the homes.
“From mid-November, local residents noticed excess water in the streets above Penny Lane [where the house was destroyed],” Costello explained.
“The water, we’ve been told, surged through the stormwater drainage system.”
“It broke through the roads, cracked the asphalt, created potholes, and flowed down the streets. It soaked the nature strips and leaked into the curbs.”
A “constant flow” of water was also seen coming from a section of the escarpment affected by a smaller landslide roughly a week before the larger event that destroyed the house. When two residents investigated, they traced the issue to a water main that appeared to have saturated the area before it was repaired in early January, Costello added.
He told the inquiry that the residents approached the Mornington Peninsula Shire council and South East Water, but received what he termed “insubstantial responses.”
Five lines of inquiry are being examined
The “burst water main theory” is one of five areas the Board of Inquiry will explore to determine the cause of the January disaster and how to prevent a similar event in the future.
Other water-related causes under consideration include the adequacy of the area’s stormwater infrastructure and the presence of natural underground springs. The impact of building works, such as the installation of a retaining wall on an uphill property and vegetation removal, is also being scrutinized. Property owners claimed that vegetation removal was limited to dead plants and minor trimming at the request of a neighbor.
“We have not reached any conclusions regarding whether any of these factors contributed to the landslide,” Costello stated.
“However, these issues may have played a role in creating conditions that could have facilitated the landslide, even if they weren’t directly causal.”
In 1952, eight homes were destroyed in a landslide triggered by heavy rainfall about two kilometers from the McCrae site, the inquiry was told.
Before two smaller landslides occurred near the site in November 2022—following 80 millimeters of rain, the heaviest recorded in a single day in more than a decade—three homes were evacuated.
A week before the major landslide in January, a smaller event caused significant damage to the home that would later be destroyed while two residents were inside.
Despite this history, the inquiry learned that the area was not subject to an erosion management overlay, a planning tool that could impose stricter development regulations in areas prone to erosion.
Led by senior lawyer Renee Enbom, the inquiry has reviewed numerous documents, examined over 30 submissions, and visited the affected region and its residents.
Ms. Enbom expressed her commitment to delivering the findings swiftly.
“It is time to find the answers to the crucial questions being asked by the McCrae community,” she said.
“I am determined to provide recommendations as quickly as possible to help prevent or mitigate the risk of another landslide.”
The hearing is set to continue over the coming weeks.
