In March 2022, a severe weather system combined with La Niña brought so much rain to the north-east of Australia that Brisbane, the state capital of Queensland, received 80% of its annual rainfall in just three days. As rivers overflowed, over 15,000 houses flooded. The state was hit by similar severe flooding in 2011.
As the unpredictable storm stretched south, Lismore, a town in northern New South Wales, was flooded. The local river reached water levels over 14 metres, more than two metres higher than the previous peak in 1954. With little warning, hundreds of people were evacuated, abandoning lifelong belongings. Further south, flooding caused damage and chaos in Sydney. Tragically, 22 people have died directly from the recent floods. The emotional toll for survivors is great and recovering from the loss of homes, businesses and personal possessions will take years.
A rise in unpredictable weather patterns
Australia’s recent experience is only one example of unpredictable weather. With the increase in unpredictable weather patterns, many cities are improving infrastructure. However, “Most of the focus remains on big engineering solutions like flood walls and embankments rather than a more holistic plan that would involve every level of society,” said British scientists from the University of Nottingham in a report for academic magazine The Conversation.
Across the world, various flood-management strategies are being implemented. In Germany, the Netherlands and France, flood levees, flood protection and defence structures as well as mobile barriers are providing effective flood management. Similar investments have been made in Australia, such as the temporary flood levee which saved the flood-prone town of Maryborough, 250km north of Brisbane.
Effective flood management
The Maryborough levee consists of steel A-frames and covered by plastic sheeting weighted down with a heavy-duty chain. It is a similar model Rockhampton City Council used in the 2017 floods. In Maryborough, the levee can be assembled by a team of 30-40 people within six hours. Although numerous houses and businesses were impacted when the flood peak reached 10.3-metres, Maryborough was able to save most of its central business district from flooding in early 2022.
Fraser Coast mayor George Seymour told ABC News that without the levee, the whole CBD would have been under water. “The state government provided funding for us to purchase it for flood protection,” he said. Queensland government paid A$4.8m ($3.48m), while the council provided A$1.2m for the levee – an example of coordinated flood mitigation, and worthwhile investment as prior floods in 2011, 2012 and 2013 caused nearly A$43m of damage.
The decision on levees or even individual solutions for households or businesses is a particularly complicated one, where costs, maintenance and aesthetics have to be considered. In Lismore, for example, the CBD levee was constructed in 2005 after 30 years of debate that culminated in council deciding on a one in 10-year recurrence interval. The 2022 floods have rendered this insufficient, along with any simple measures, where water levels rose to cover two-storey buildings in some areas.
Do whole towns need to be relocated?
There really isn’t a one-size-fits-all solution to the issue. As Gallagher Re flood expert Denis Simanovic said, “While levees and other structural mitigation measures work well to protect some locations, the physical nature of flooding in other locations means that their ability to reduce the risk is inefficient at best and a detriment to surrounding areas in a worst-case scenario.”
This raises the question of whether if it would be more viable to relocate townships. However, while Grantham in Queensland set a precedent for partially relocating highly-flood-prone towns, Lismore is a much larger regional city with a population just short of 30,000, a significant percentage of which live with some flood risk.
“Voluntary purchases or moving the entire town would therefore be a very expensive mitigation option,” Mr Simanovic said. While costly, conditions suggest such measures may be necessary, unless an alternative mitigation approach is found. In addition, much more care with future town planning for business and residential areas should be implemented.
Larger-scale flood mitigation
While larger-scale dam projects have been proposed in Australia, not everyone is convinced this is the best approach to managing water security. There are other larger-scale mitigation methods that lead well beyond the focus on engineering.
Scientists from the University of Nottingham point to so-called blue-green infrastructure, which uses the planning system to integrate rivers, canals or wetlands (the blue) with trees, lawns, parks or forests.
“This can involve anything from small-scale ‘rain gardens’ that allow water to drain naturally through soil, through to much larger-scale artificial wetlands or ponds,” they wrote in a report for The Conversation.
China introduced so-called ‘sponge cities’ in 2013. The port city of Ningbo is one such example, where a 3km strip of brownfield was transformed into an eco-corridor and public park. This and other sponge cities use nature to absorb, clean and distribute water, rather than using concrete to channel rainwater away. More research is needed, however, to understand if this is viable for significant weather events happening in Australia.
Managing risks efficiently
Flood losses can be minimised with efficient prevention. A necessity, however, to start the process, is high-quality flood models.
“This is the single most important investment that a local government can make in understanding the underlying risk of flooding to their local community,” said Mr Simanovic. “These will form the basis for deciding on future mitigation options.” Those options will be critical for town planning and mitigating risks in future natural catastrophes.
Most insurers have a Nat CAT plan to manage their risk from major weather events. HDI Global regional claims manager Australasia and ASEAN David Lloyd said, “From an insurance perspective, however, no matter how good that plan is, you can’t anticipate every eventuality.
“This is why the development of AI, satellite imagery and GPS mapping to assess the extent of damage within hours of the event is critical to assisting insurers early and providing insurers with the ability to assist the insured more quickly thereby reducing damages and quantum.”
Logically, this is quite an investment, but it is slowly becoming a ‘must have’ for insurers, governments, organisations and local communities.
“Insurers need to see prudent investment to reduce exposure to flood events and subsequently insurance costs,” Mr Lloyd said. “The first step is to show the intent to mitigate, the second is funding and the third is implementation.”
While these all take time, with the frequency of significant weather events, a coordinated societal approach and greater investment into flood mitigation will be critical for towns and cities at greatest risk over the next few years.
In the short term, communities have come together to support each other. Relief payments have been made available by the government and 7,000 defence personnel are working on the flood recovery nationally.
In the longer term, there is an opportunity to learn from these events and plan for the future. Together, we can do better, and insurance can play a role in helping organisations and governments do this. A
Mr Stefan Feldmann is managing director of HDI Global in Australia.