CSIRO report: ‘most comprehensive flood mitigation study ever undertaken in Australia’

By Samantha Elley

It is the most comprehensive report on flood mitigation ever done Australia-wide and has been four years in the making since the 2022 floods on the Northern Rivers.

The CSIRO report was released last week and provides indepth information on how dry holding ponds or detention basins could be the solution to reducing the impact of future floods when they occur.

Many in the community, however, are concerned the report could end up as a dust collector on a bureaucrat’s bookshelf if the next step after its release is not undertaken.

“It is impossible for flood mitigation to be implemented in our region unless you have accurate, reliable, trustworthy data that you can make decisions on,” said Our Future Northern Rivers spokesperson Richard Trevan.

Our Future Northern Rivers started as a flood review group after the 2017 flood and Mr Trevan said a catchment wide solution was needed.

“This is the first time it has been done,” he said.

“It is a ground-breaking piece of science and now the decision makers are in a position to confidently move forward whereas for previous generations that was not the case.”

Mr Trevan said the Northern Rivers is the most flood-impacted region in Australia.

“Floods remain the most deadly and expensive disaster in our nation,” he said.

“This project will clarify that we now have the evidence to make a decision.

“What is missing is the ability to take that evidence and transform it into implementation.”

He said he was pleased to hear the state government will commit $3 million to the next step.

However, for the project to be implemented properly Mr Trevan said the federal government needs to step in.

“This issue of 97% of funding that has been dedicated to reparations and only 3% to mitigation, that has to change,” he said.

“If they do not do this next step properly at federal level we will remain at status quo.”

Federal member for Page, Kevin Hogan also calls on the state and federal Labor governments to act on the recommendations from the CSIRO report.

“It’s not IF we have another flood in our region, it’s WHEN,” he said.

“When we reduce flood risk, businesses invest, insurance becomes affordable again and families choose to stay and build their futures here.”

State member for Clarence, Richie Williamson is calling for urgent action to ensure the findings from the CSIRO report are translated into real outcomes for communities.

“This is arguably the most comprehensive flood mitigation study ever undertaken in Australia and certainly the most significant piece of work our region has seen since the devastating 2022 floods,” Mr Williamson said.

“For the first time, we have sophisticated, catchment-wide modelling backed by world-class science demonstrating that strategically located flood mitigation infrastructure has the potential to substantially reduce flood levels, flood depths and flood inundation across the Richmond River catchment.

“The report confirms that major floods cannot be prevented, but importantly it shows their impacts can be significantly reduced through carefully planned flood mitigation measures.”

Graham Askey has lived through many floods in Lismore and has also been involved with community groups involved with flood mitigation.

“If the detention basins had been in (in the 2022 flood) and two metres had been taken off that flood, it would not have come up to my window sills,” he said.

“It would have been a metre under the floor and the same goes for nearly every raised house in Lismore.

“A super major flood would (have been) reduced to a major flood.”

Highlights from the CSIRO report

• A number of detention dams to be located at strategic points throughout the Northern Rivers to be temporary storages for flood water then released when the flood peak has passed so river flow is not impeded.
• The opening to the Pacific Ocean at Boundary Creek would be a modified flow path that allows floodwaters to discharge to the ocean during flood conditions, thereby reducing downstream flood impacts along the Richmond River.
• The Tuckombil upgrade would see the replacement of the fixed-height barrage with pressure gates.

You can read the full CSIRO report at www.nema.gov.au.