Drainage
systems were not always designed to today’s modern standards – to understand
how we can improve drainage systems, we study the impact of storm events across
Greater Geelong.
Before the late 1970s, drainage systems were built to handle smaller storms, usually no bigger than a 1-in-5-year event (20% chance each year). Older areas weren’t designed to deal with heavy rain, making them more likely to flood during large storms.
The Victorian Government's Drainage of Land Act 1975 allowed for better rules for building on flood-prone land. Since then, new neighbourhoods have been designed with improved drainage.
Modern systems can handle both normal rain and major storms, including 1-in-100-year events (1% chance each year).
Roads and other public spaces are part of the drainage system so it’s normal to see water on roads in areas built after 1980 during heavy rain. These designs keep water levels safe during big storms. Always avoid floodwater and move to higher ground if flooding happens.
Upgrading old drainage systems or reducing flooding in older neighbourhoods is tricky and expensive due to the way they were built.
We still use 1-in-100-year storm events to define flood risks and create rules under laws like the Water Act 1989 and Building Act 1993.
If you see water not draining after rain, it might mean a blocked drain. Report it online, the Geelong City App, or call us on 5272 5272.