|dc.description.abstract||Flood-related disasters are on the rise, exacerbated by the worsening climate crisis, despite substantial investments in protective measures. Recent extreme weather events have demonstrated that even areas considered relatively safe can be susceptible to flooding. This calls into question the adequacy of our existing flood management strategies.
Historically, flood management has focused heavily on constructing higher levees and expanding drainage systems. While these measures contain water effectively most of the time, they can lead to catastrophic floods when they exceed their original design capacity. Moreover, they operate under the flawed assumption that future flooding can be reliably predicted based on historical flood data. This false sense of security encourages development in flood-prone regions.
The increasing unpredictability of rainfall patterns and intensities due to climate change has rendered these historical design assumptions inadequate. As a result, a significant "residual risk" persists, even after infrastructure improvements and plans for future enhancements.
To illustrate this, consider wearing a seatbelt while driving. The seatbelt reduces harm in the event of an accident but doesn't guarantee complete protection from injury. Now imagine road conditions deteriorating, weather becoming more unpredictable, and traffic volumes increasing. Some might opt not to drive due to the heightened risk, but for those already on the road, it's too late. This parallels how many countries continue to manage floods—often by constructing higher levees or larger drainage systems. However, this incremental development often lacks the strategic investment and infrastructure capacity required to safely manage excess water volumes during failures.
While housing development is essential, current flood risk assessments often neglect both current and future flood risk. Planning controls and additional infrastructure costs are frequently criticized as "red tape," further increasing residual risk. Recent weather-related disasters, such as Cyclone Gabrielle in New Zealand and wildfires in the northern hemisphere, have underscored the need to understand and manage residual risk. However, the recognition and incorporation of residual risk management in planning policies vary from one country to another, with many lacking clear national directives.
In New Zealand, for instance, there is limited national-level guidance on flood risk management. Still, flood risk professionals are increasingly aware of the rising residual flood risk, primarily due to climate change and continued development in flood-prone regions designated as "protected." There is consensus that current flood risk management practices need improvement.
Overcoming these challenges requires acknowledging and managing the growing residual risk linked to climate change. A more informed approach involves implementing robust guidelines against ill-advised development in flood-prone areas unless accompanied by infrastructure investments that reduce residual risk. Resilience-building measures, such as creating "sponge cities" and increasing space for water in flood risk management, are gaining traction. To break the cycle of disaster recovery and financial losses, planning must prioritize residual risk considerations in response to more frequent flooding and inevitable infrastructure failures.||