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Flash Flooding 18 October 2024

Yarra Ranges Shire Council

Following the heavy rainfall and flash flooding yesterday (Friday 18 October 2024) a number of roads were closed. They have since been reopened.

We understand how difficult these flash flooding events are for our local residents and businesses and Council can confirm that prior to these forecasted heavy rains, drains and pits in areas that are prone to flash flooding were checked.

Heavy and quick rainfall results in flash flooding. The underground drainage system cannot always capture the volume and fast-moving water as it hits the ground when flash flooding occurs.

It is important to understand that the roads are an integral part of the drainage system and during heavy rains will carry water, with drivers needing to drive to conditions. Flash flooding on roads usually drains away relatively quickly once the heavy rainfall stops.

It is not always possible to fix localised flooding by adding new drains or making drains bigger, as this often shifts the problem downstream.

The best approach is to model and plan for where flooding might occur, allowing for the safe flow of water while minimising the impact on buildings, businesses, and other infrastructure.

Council has allocated $16 million to be spent on drainage over the next six years and has just completed consultation on a Stormwater Management Plan.

Yarra Ranges is the second most disaster-impacted council across 479 local governments in Australia, underscoring the urgent need for comprehensive, forward-thinking strategies to enhance climate resilience.

Council also presented at the State Government’s Committee Inquiry into Climate Resilience last week where flooding was raised.

Local councils need targeted flood modelling to identify areas of greatest vulnerability, prioritize infrastructure investments, and reduce flood risks in those locations. With limited resources and many areas to address, it’s essential that we focus on the places most at risk.

But we can’t do it alone. We need strong centralised data and analytics to prioritise and sustainable funding for resilience initiatives and to build community awareness.

Flood mapping involves computer modelling, which simulates how stormwater runoff travels through catchments. Current and reliable flood mapping information is essential to understand and manage flood risk. It is used to:

• Assess the frequency, severity, and location of flood risks within catchments

• Better plan and prioritise mitigation activities

• Plan for future development

• Build community awareness

• Inform emergency management planning

Council continues to work with Melbourne Water and other government agencies in managing the drainage network under the roads and continues to advocate to State and Federal government for longer term assistance. Council also acknowledges that there cannot always be an engineering solution to manage flash flooding events.

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