On a late October afternoon in 2022, a 15-minute burst of torrential rain coated Lilydale in 75mm of water. Main Street was transformed into a river as waves of water rushed through the doors of businesses.
Yarra Valley Smokery owner Alex Tsao estimates the flood cost about $10,000 in ruined stock. It was the third time his business had been inundated in 10 years.
University of Melbourne professor of urban ecohydrology Tim Fletcher says increasingly intense rainfall means events like Lilydale’s 2022 deluge are likely to become more common, and that Melbourne’s current drainage system is not equipped to cope.
“Flooding will get more frequent if we don't spend money to upgrade,” he said. “There’s a really clear increase in those rainfall intensities as the climate gets warmer.”
What’s the cost? Infrastructure Victoria says extreme weather events cost the Victorian economy an average $2.7 billion a year between 2006 and 2016. The 2022 floods caused $3.5 billion in insured losses.
Heavy rain makes Tsao and his staff “tentative”, with reports of rain often prompting him to return and sandbag the business.
🗣️ “That sort of trauma will always be there because you want to make sure that you catch it early,” he said.
What can be done? Across Melbourne, local councils manage 25,000km of drains and street gutters, while Melbourne Water is responsible for 1,400km of regional drains.
Intense rainfall events often lead to stormwater overflow, while weather shifts and urban growth has added to stress on the system.
Melbourne Water says bringing all drainage assets up to date would be “too costly and disruptive”, so high-risk areas are prioritised for upgrades.
Infrastructure Victoria says the state’s flood data is “outdated and unreliable” and has recommended the government update flood maps and planning schemes.
Paying for pipes: In Knox, replacing all council stormwater assets — including more than 1,150km of pipes and 39,673 drainage pits — would cost an estimated $292 million.
Yarra Ranges Council’s Anita Curnow said the council spends more than $2 million a year on maintenance and cleaning.
Balancing spending: Fletcher acknowledged “you can't guarantee there'll never be any flooding anywhere at a reasonable cost”, but said “there does need to be an investment to manage the level of risk to an acceptable risk”.
He said beyond investing in new infrastructure, another potential solution was improving how the current infrastructure controls the flow of water.
Essentially, separate drainage assets, such as household rainwater tanks, council-owned storages, urban lakes and wetlands can be controlled in real-time to retain and release water into other parts of the network and avoid overwhelming ageing infrastructure.
Holding on: For business owners like Tsao, there is only so much an individual business can do.
🗣️ “We hope for the best, but it’s hard to predict the future,” he said. “We’ll do what we can to mitigate but if it happens, we just need to roll with it.”