LISMORE — The CSIRO released a report on Tuesday concluding that building 10 new water detention systems in New South Wales's northern rivers could have reduced flood levels by up to 2.1 metres during the February 2022 floods. The report was commissioned by the Morrison government four years prior to its release.

Extensive flooding between late February and early April 2022 in the northern rivers led to the deaths of 13 people. More than 4,000 properties were left uninhabitable, and another 10,849 were damaged. The total socioeconomic and structural damage from these floods is estimated at $16 billion.

The report investigated two flood mitigation proposals: Bundle 1, which included five new water detention systems, and Bundle 2, which included 10 water detentions across the Richmond Valley, Kyogle, Ballina, and Lismore local government areas. Modelling showed water levels could have been reduced by up to 1.7 metres during the flood on March 31, 2022, and by up to 1.4 metres during the 2017 floods. The flood level in Lismore reached 14.4 metres in February 2022, the highest on record.

The proposed water detention systems would not have prevented the 3.8-metre over-topping of the Lismore CBD levee in February 2022. CSIRO hydrologist Jai Vaze said, "We can reduce the impact of large floods with strategically located detention and other flood mitigation measures across the entire Richmond River catchment."

Despite the report, the state and federal governments have not committed to delivering the measures modelled as part of the $11.4 million Northern Rivers Resilience Initiative. On Tuesday, the governments announced a joint $3 million feasibility study.

Janelle Saffin, state MP for Lismore, said, "My reading of this report gives us real hope because it shows technically that flood levels can be lowered across all four local government areas in the Richmond River catchment." Kevin Hogan, federal Nationals MP for Page, added, "The CSIRO have provided a solution to keep us safe. The state and federal Labor governments must act on this."

NSW Greens upper house member Sue Higginson said, "This is not renewed hope to think that we can engineer our way out of climate change." Business operator Matthew Gooley said, "Take two metres off [2022 levels] and it goes back to normal flood [heights], not getting in people's top levels." Business owner Paul Morgan said, "There have been a few interesting ideas over the years."

Resident Irene Guymer said, "I really do they think would be better off … shift[ing] the CBD up to Goonellabah where a lot of people … and businesses have gone." Artist and musician Jimmy Willing said, "It's a bit like putting men on the moon while people are starving."

As of this month, 813 properties have been bought back under the Resilient Homes Program, and 70 resilient measures have been completed. A NSW auditor general's report found that after three and a half years, the program had yet to deliver a single home or lot.