A CSIRO report released on Tuesday reveals that building 10 new water detention dams in New South Wales’ northern rivers could have reduced flood levels by up to 2.1 metres during the devastating 2022 floods. However, the measures would not have prevented the Lismore CBD levee from overtopping by 3.8 metres.
Report Details and Findings
Commissioned by the Morrison government four years ago, the report examined the one-in-100-years floods that struck the northern rivers between late February and early April 2022. The disaster caused 13 deaths, left over 4,000 properties uninhabitable, damaged 10,849 more, and resulted in an estimated $16 billion in socioeconomic and structural damage.
CSIRO hydrologist Dr Jai Vaze, who led the report, stated: “We can reduce the impact of large floods with strategically located detention and other flood mitigation measures across the entire Richmond River catchment.” He emphasised that these systems are temporary, with gates closing only when flood waters rise beyond a certain level, unlike permanent dams.
Proposed Mitigation Measures
The report modelled two bundles of proposals. Bundle 1 includes five new water detention systems plus upgrades, while Bundle 2 comprises 10 water detentions across the Richmond Valley, Kyogle, Ballina, and Lismore local government areas. Bundle 2 showed the greatest potential, reducing water levels by up to 2.1 metres during the February 2022 flood, which peaked at 14.4 metres—the highest on record. It could also have reduced levels by 1.7 metres during the March 2022 flood and 1.4 metres during the 2017 floods, both keeping water below levee banks.
Government Response and Community Reactions
The state and federal governments have not committed to the measures modelled in the report as part of the $11.4 million Northern Rivers Resilience Initiative. Instead, they announced a joint $3 million feasibility study on Tuesday. Federal minister for emergency management Kristy McBain and NSW counterpart Janelle Saffin welcomed the findings, with Saffin saying, “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.”
Lismore residents had mixed reactions. Matthew Gooley, operator of a family-run menswear business in the CBD since 1957, lost “millions in stock” in the floods. He said the measures would be “amazing for Lismore” and could “take two metres off and it goes back to normal flood heights.” Paul Morgan, owner of Lismore Computer Solutions, said he was “all for it if it works.” However, Marinda Hayward, left homeless by the floods, called the $3 million feasibility study “a lot of money” and preferred spending on practical measures like drain cleaning. Irene Guymer, whose daughter’s farm flooded, called the measures a “waste of money” and suggested moving the CBD to Goonellabah. Artist Jimmy Willing criticised the spending while Lismore faces a housing crisis, saying, “It’s a bit like putting men on the moon while people are starving.”
Political Reactions
NSW Greens upper house member Sue Higginson, a Lismore local, argued the report shows that “billions of dollars in new dams for the Richmond River will not prevent severe flooding.” She called for “planned retreat and nature-based solutions” including replanting forests and transforming the Lismore CBD into a “wetland cultural market hub.” Federal Nationals MP for Page Kevin Hogan, who has led calls for engineering works, said the report “details how flood mitigation could make our communities safer” and urged state and federal Labor governments to act. Both have criticised the rollout of the $100 million Resilient Lands Program and $880 million Resilient Homes Program, which have faced delays and controversies. A NSW auditor general’s report last month found the RLP had yet to deliver a single home or lot after three and a half years.
