“Significant downpours” on the rise: How can the Yarra Ranges prepare for increased flash flooding?

On October 25, 2022, in the space of an hour and a half, Lilydale’s Main Street was transformed from a relatively quiet retail thoroughfare into a torrent of water as close to 75 millimetres of rain fell in a short period of time.

However, this incident was far from the only flooding event local residents have experienced recently.

To gain a clearer picture of the future flood risk facing the region, Yarra Ranges Council is joining with Melbourne Water to update 12 flood maps across the area.

How and why are heavy rainfall and flooding becoming more frequent and regular?

According to the State Government’s 2024 Climate Science Report, with each degree the Earth warms, the atmosphere can hold about seven percent more water vapour, leading to more moisture in the air and more extreme weather patterns.

Environment Victoria reports global warming – and humanity’s dependence on fossil fuels – directly causes this extra water to be created and stored.

As extreme weather events become more frequent, the existing infrastructure of much of our community will need to be upgraded. Lilydale is just one example where a suburb is no longer best designed to cope with an event like flash flooding.

What has been the response from local emergency services?

Lilydale State Emergency Service (SES) unit controller Shaun Caulfield said Lilydale and the broader Yarra Ranges area had experienced more frequent significant rainfall events recently.

“We have seen an increase in the frequency of flooding events in the last five to 10 years, but we’re also seeing a change, generally, in our weather patterns and weather cycles,” he told the Eastern Melburnian.

“We get significant downpours in a short period of time which obviously overwhelms the existing infrastructure.”

Caulfield said he and other local SES unit staff members and volunteers were “very interested” to see what the outcomes of the review will be.

“The majority of Lilydale is sitting on infrastructure that was designed 30 years ago or more and it would have been designed on both the science and the information that they had at that time,” he said.

“Obviously, Melbourne Water has seen that it’s the time to review that in light of what we know in relation to climate science and weather science.”

How are Lilydale locals being impacted?

In November 2023, Lilydale locals launched the Lilydale Flood Watch Facebook page, which now has more than 1,500 members.

A founder of the page told the Eastern Melburnian they had been living in the region for 25 years and things had only gotten worse over the past five to 10 years, with any rainfall event causing them concern.

What more can be done?

An Insurance Council of Australia (ICA) spokesperson told the Eastern Melburnian reducing risk should be a key priority in helping to cut down on insurance costs for homeowners in areas of high flood risk.

“The ICA is calling for a major uplift in flood defence infrastructure and is working with all levels of government to reduce climate-related risks,” the spokesperson said.

Earlier this year, the ICA called on the federal government to invest over $30 billion to better prepare the country for incoming flooding – a weather event it declared was Australia’s “costliest extreme weather type.”

What will the new mapping achieve?

As part of the Greater Melbourne Flood Information Program, Melbourne Water is working with local councils to update flood maps, with information used to plan for infrastructure, new housing developments and emergencies.

Locals wanting to have their say on how flooding has recently impacted their neighbourhood can do so before 11.59pm on Sunday 24 August.

Image Credit: Lilydale SES