Fears Brisbane River will flood again amid La Nina Summer as development continues

An expert warns “it’s not a question of if, but when” the Brisbane River will flood, as council says it’s unable to clarify how many developments have been greenlit on our flood plains.

A leading researcher has warned the Brisbane River will flood again, as council admits it doesn’t know how many development applications it’s approved on the city’s flood plains.

The Courier-Mail asked Brisbane City Council to outline how many developments were approved in the 2019-20 financial year in areas which flooded in 2011, only to be told the data wasn’t readily available.

It comes as Queensland faces the same La Nina conditions this summer as that which generated the devastating floods of 2010-11, which inundated thousands of properties across the state.

This summer’s weather patterns are expected to generate more tropical cyclones than average, which in turn increases the likelihood of torrential rain in the Brisbane River catchment.

Flooding in 2010 at a site on Tingal Rd, Wynnum. Pic Jono Searle

University of the Sunshine Coast researcher Dr Margaret Cook, who last year published her startling history of floods in the Brisbane River catchment, A River with a City Problem, has warned the 2011 floods were only minor compared to previous floods in 1893 and 1974 and that dams had a finite ability to prevent a disaster.

Dr Cook also expressed alarm at the rate of development in Brisbane.

“My concern is that development is still happening in areas that flooded in 2011,” she said.

“We’re building more houses, and we’re putting more people in them through subdivision or through high rise blocks.

“It’s going to be harder to rescue them.”

A River with a City Problem author, Margaret Cook said historical evidence showed Brisbane would inevitably flood again. Picture: Rob Williams.

Dr Cook said, compared to 2011 when the Brisbane Port Office gauge hit 4.46 metres, previous floods had recorded 8.35 and 8.09 metres in 1893 and 5.45 metres in 1974, all three of which followed rainfall from tropical cyclones.

“You can mitigate the floods with dams, but they have a finite capacity,” she said.

“So no, Brisbane will flood again. It’s not if, but when.”

Brisbane City Council said it had enacted a number of policies to make Brisbane more resilent to flooding. Picture: Russell Shakespeare

She however praised Brisbane City Council for “considerable work” in ensuring the city and post-2011 buildings were more resilient in floods.

A Brisbane City Council spokesman said “we have built a city that is safe, confident and ready for weather events”.

“We are committed to ensuring all development is resilient to flood impacts,” he said.

“Any application submitted for an area with a flood overlay will need to be designed to ensure all habitable spaces are located higher than non-habitable spaces.”