‘Rain gardens’ could help Brisbane avoid next flash flood, expert says

“In their simplest form they are a trench with gravel, but they can also be grassy areas with plants that act as drainage systems but also look beautiful.”


WSUD techniques are already being used in parts of Brisbane and other cities, but Prof Deletic said she would like to see them used in urban areas.

“The more you have, the more water can’t immediately flow to local streams, which adds up and hopefully prevents larger flash floods,” she said.

“In Europe they are used a lot, and China is starting to use them quite widely – they hold up to sudden heavy downpours very well.”

Prof Deletic said WSUD solutions were also scalable, meaning they could be implemented at community level or even by individual homeowners as part of designing their own gardens.

On Wednesday, Deputy Premier Steven Miles said around 2,500 homes in southeast Queensland suffered moderate damage in the recent floods, while around 1,800 were severely damaged.

Mr Miles acknowledged that unlike the 2011 floods, flash flooding and creek flooding caused a significant portion of the damage in 2022, and future flood mitigation efforts should take this into account.

He said levees, stormwater or ebb drainage improvements, home buyouts and higher home reconstructions were all being considered.

“This disaster was quite different, and where in 2011 we could look at where the river overflowed, in this case we have to look at each neighborhood and what caused the flooding,” Mr Miles said.

“Now this might take a bit longer, but it will allow us to consider what the best options are. [for rebuilding].”

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