By Rachel Eddie
Flood mapping for Melbourne’s inner-western suburbs was so outdated that it was irrelevant when more than 500 homes were inundated last year, and resulted in “substantially dangerous” warnings for the 1000 residents ultimately evacuated, a parliamentary inquiry has heard.
On a day when Melbourne Water managing director Nerina Di Lorenzo was asked why she still had a job at the authority after its role in the October 2022 floods, three councils in the Maribyrnong catchment gave evidence that outdated flood maps hampered the emergency response.
Melbourne Water managing director Nerina Di Lorenzo at the hearing on Wednesday.Credit: Luis Enrique Ascui
Moonee Valley Mayor Pierce Tyson told the upper house inquiry on Wednesday the decision by Melbourne Water to issue a moderate flood warning for part of the catchment was “substantially dangerous” for residents who went to bed on October 13 believing they were safe before a major flood warning overnight.
The first time many residents in Maribyrnong learnt they should evacuate was via text messages sent by the State Emergency Service between 4am and 6am.
Under questioning on Wednesday, Di Lorenzo was forced to defend her position at the authority, which also drew criticism for the lack of independence of a separate review into the flood commissioned by Melbourne Water.
“We do not shy away from the fact that there’ll be things to learn, and no agency should ever do that,” Di Lorenzo said. “So that’s absolutely what I’m focused on. And you know, I was in the role of [managing director] for nine months when the flood hit. I’ve got to tell you that this has been a key focus for me, and we are chasing down the facts.”
Victoria Racing Club chief executive Steve Rosich.Credit: Luis Ascui
The inquiry, established by the Coalition, Greens and crossbench after extensive reporting in The Age, also probed the controversial flood wall around Flemington Racecourse.
Victoria Racing Club chief executive Steve Rosich on Wednesday repeatedly declined to be drawn into debate at the inquiry about whether the 2.4-metre-high wall pushed floodwater into neighbouring homes.
“That’s for the experts to determine,” Rosich said. He said it served its purpose, by keeping the racecourse mostly safe from flooding.
Melbourne Water said it had no evidence the wall – built in 2007 with the approval of the then-Labor planning minister against the wishes of three local councils – exacerbated flooding for neighbouring homes and businesses. Further modelling will be released in April.
Representatives from three councils overseeing the catchment – City of Melbourne, City of Maribyrnong and City of Moonee Valley – that were devastated by last year’s floods all raised concerns at the inquiry about the wall.
City of Melbourne general manager of planning Evan Counsel said: “The anecdotal evidence of what occurred on the day, and the imagery, is quite stark and quite compelling.”
Maribyrnong planning director Laura-Jo Mellan and Tyson said flood mapping should be updated as quickly as possible to reflect changes to drains or roads that may affect water flows.
Tyson said: “Ideally, you’d have a system where emergency services in the [State Emergency Service] actually rely on that mapping, where it was completely irrelevant for our SES during the event.”
Counsel said much more frequent modelling at a broader scale was needed to take in the catchment rather than the boundary of each local government. He said this should be updated every five years at an absolute minimum.
The councils argued door knocks and an air siren could be necessary in future to ensure residents were alerted to any risks.
The report of a review into the floods commissioned by Melbourne Water was released last Friday.
That review was criticised from the outset because of a perceived lack of independence and its limited scope.
Victoria SES Volunteers Association president Faye Bendrups gives evidence on Wednesday.Credit: Luis Ascui
The initial chair of the review, Nick Wimbush, was forced to quit in February after The Age revealed his previous role in planning changes that allowed new developments in areas that flooded.
The water authority has committed to implementing all the recommendations.
Victoria SES Volunteers Association president Faye Bendrups agreed that updated catchment-wide flood mapping would be more useful than those broken up by each municipality.
“All the different councils and requirements and needs of all the different areas should be coordinated into one plan for the whole of catchment. The river is not going to flood in one part of it and then not the other,” Bendrups said.
Di Lorenzo last week said that since the October floods, Melbourne Water had begun providing new flood modelling for every river catchment in Melbourne by the end of 2026, including climate change impacts projected to the year 2100.
John Woodland, head of waterways and catchment services for the south-east at Melbourne Water, told the inquiry the authority had sophisticated models and its forecast modelling was constantly updated.
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