Melbourne Water says it is focused on managing flood risks around a recently-inundated retirement village in Bangholme.
Answers had been initially in short supply from authorities after Willow Lodge was flooded by overflow from a nearby retention pond on Tuesday 16 July.
Star Journal enquired with Melbourne Water, Department of Transport and Planning, and Greater Dandenong Council but each blamed the other for an apparent backflow issue at a nearby floodgate.
The village of more than 500 residents is on floodplains between the banks of Eumemmerring Creek and Eastern Contour Drain, and downstream from a Melbourne Water retarding basin.
The complex is surrounded by a ring of flood-protection levees as well as a retention pond.
Melbourne Water regional manager Dan Besley said “local residents should feel confident (that) flood risks are being managed”.
“Melbourne Water is working with relevant authorities to ensure this issue remains a focus.
“The flood gate and local drain near Willow Lodge are managed by other agencies, however we are in communication with the local council, who have confirmed they are also following up with VicRoads.”
The flood gate at Frankston Dandenong Road is believed to be managed by the Department of Transport and Planning.
Last week, Melbourne Water confirmed that the flood occurred due to the flood gate failing to close during heavy rainfall. It was likely stuck open due to debris.
As a result, water from a Melbourne Water main drain backflowed into a local drain.
A private drainage pump station at the Willow Lodge retention pond, which was designed to divert water into the main drain further downstream, was unable to cope with the backflow.
A week earlier, Greater Dandenong councillor Rhonda Garad raised the alarm on behalf of Willow Lodge residents on the proposed rezoning of paddocks at 250 Fernside Drive for industrial development.
At a 8 July council meeting, Cr Garad said the site was within the “Bangholme retarding basin” – a “critical” flood mitigation measure to protect residents at Willow Lodge retirement village as well as suburbs downstream.
According to a council report, Melbourne Water has stated it doesn’t have any objection to the rezoning on the basis of flood risk, “subject to conditions”.
Councillors sought a costings report on getting independent advice on the flood impact.
Bangholme flood researcher Alan Hood warns of frantic future evacuations at Willow Lodge if floods equivalent to several in the past 100 years were repeated.
At those levels, a rampaging Dandenong Creek would spread about 1.7 kilometres wide, would “roof gutter height” at Hammond Road and would “slam over” the Eumemmering Creek northern levee bank towards Willow Lodge.
“The people of Willow Lodge would need to be evacuated. But there would be no vehicular access from north or south… helicopters can’t do it fast enough.”
