A new study has found that the catastrophic floods that inundated Lismore in 2022 would have been approximately two metres lower if the region's dams had been operated differently. The research, conducted by water experts at the University of New South Wales, analysed the role of the Wyrallah Road and other flood mitigation infrastructure during the record-breaking event.
Study Details and Findings
The study modelled the 2022 flood scenario with alternative dam operations, including pre-release of water before the peak rainfall. It concluded that peak flood levels in Lismore could have been reduced by up to 2.1 metres, sparing much of the city from the worst inundation. The findings challenge the current flood management protocols and highlight the potential for better use of existing infrastructure.
Lead researcher Professor Fiona Johnson stated, "Our modelling shows that with more proactive dam operations, the flood peak could have been significantly lower. This is a critical insight for future flood planning." The study used historical data and advanced hydrological models to simulate various dam release strategies.
Impact on Lismore and Surrounding Areas
The 2022 floods caused extensive damage across the Northern Rivers region, with Lismore experiencing its worst flood on record. Over 2,000 homes were affected, and the economic cost exceeded $1 billion. The study suggests that a two-metre reduction would have kept floodwaters below many homes and businesses, potentially saving millions in damages and reducing the trauma for residents.
Local mayor Steve Krieg welcomed the research but emphasised the need for further investigation. "This study gives us hope that better management is possible, but we need real action, not just reports," he said. The findings have sparked debate among water authorities and emergency services about the trade-offs between flood mitigation and water supply security.
Implications for Flood Management Policy
The study raises questions about the current operating rules for dams in the Northern Rivers, which prioritise water storage for drought periods. Critics argue that flood mitigation should be given higher priority, especially in light of climate change projections indicating more intense rainfall events. The researchers recommend a review of dam operations and investment in additional flood mitigation infrastructure, such as levees and detention basins.
The New South Wales government has committed to a flood inquiry and has allocated funds for improved flood warning systems. However, the study's authors stress that operational changes to dams could provide a cost-effective solution in the short term. "We can't change the weather, but we can change how we manage our water resources," Professor Johnson added.
Community Reaction and Next Steps
Residents of Lismore have expressed frustration that the potential for reduced flooding was not realised in 2022. Community groups are calling for immediate changes to dam operations and greater transparency from water authorities. The study is expected to inform the upcoming flood review and could lead to policy changes at the state level.
As climate change intensifies, the need for adaptive flood management becomes more urgent. The Lismore case serves as a stark reminder that existing infrastructure, if used wisely, can make a significant difference in reducing flood risk.
