The impact of large floods in the NSW Northern Rivers region could be reduced by building infrastructure to store and release water, CSIRO has found.

The research agency’s final report on the Northern Rivers Resilience Initiative says water detention would enable floodwater to be held temporarily upstream of towns, then released later.

This would keep water within flood banks and enable rivers to flow normally during non-flood times.

It is possible to reduce flood peaks, inundation and depth across the Richmond River catchment with water detention and other mitigation, the report says.

The National Emergency Management Agency engaged CSIRO to investigate after catastrophic floods in Queensland and northern NSW in February and March 2022 led to insured losses of $4.8 billion. Seven people died in NSW and the Northern Rivers flooding was considered unprecedented, particularly in towns such as Lismore and Ballina.

CSIRO has mapped the Richmond River catchment, across seven local government areas, and modelled six scenarios in which water detention is used.

The NEMA and CSIRO will visit the region this month to discuss the report at community drop-in sessions.

The report notes more work is needed on the detailed design of the mitigation options and how they would be implemented.

CSIRO hydrologist Jai Vaze says the Northern Rivers methodology can be applied elsewhere.

“With a co-ordinated approach we can reduce flood heights and impacts, which can help lessen damage and support future resilience for the community,” Dr Vaze said.