Are Cities Safer From Flooding Than Before?
Cities worldwide are grappling with the challenges posed by urban flooding, - Houston TX in 2017, Venice Italy in 2019, Zhengzhou China in 2021, Sydney Australia in 2022 - and it is crucial to evaluate the effectiveness of current flood management strategies to ensure the safety and well-being of urban residents. A recent study by Guangwei Huang from Sophia University in Tokyo, Japan, provides valuable insights into the evolution of flood impacts in the Chikuma River watershed, offering lessons for cities seeking to build resilient systems. I’ve written about the Houston situation in more detail here.
Huang's research reveals that while flood fatalities in the Chikuma River watershed have significantly decreased since 1981 due to a combination of structural and non-structural measures, property damage remains high when levee breaches occur, regardless of the period. Notably, the study highlights a bottleneck in channel conveyance due to a sudden contraction in the river width, which was identified as a major concern but not addressed until the 2019 flood disaster. Furthermore, despite having a well-designed emergency management system, the vulnerability of the elderly population in the region has increased due to their weakened physical abilities and limited staff in special care homes. This last finding sadddens me. We live in the age of the best technology we’ve ever had but our most vulnerable are still even more vulnerable.
To build resilient cities, policymakers, and urban planners must prioritize a multi-faceted approach that addresses both structural and non-structural measures. This includes proactively identifying and addressing potential bottlenecks in flood management systems, such as the channel conveyance issue in the Chikuma River watershed. Additionally, cities must invest in targeted strategies to reduce the vulnerability of at-risk populations, such as the elderly, by enhancing social support networks and improving the capacity of care facilities to respond to emergencies. We’ve known this but it cannot be over-emphasized. By adopting a holistic approach that considers exposure, susceptibility, and coping capacity, cities can develop more effective flood management strategies that minimize the impact of urban flooding on communities.
In light of these findings, cities worldwide must take action to build resilient systems that can withstand the challenges posed by urban flooding. This requires a concerted effort from policymakers, urban planners, and community stakeholders to prioritize flood management, invest in both structural and non-structural measures, and foster a culture of preparedness and resilience.
By learning from the experiences of the Chikuma River watershed and other flood-prone regions, cities can develop more effective strategies to protect their residents and ensure the long-term sustainability of urban communities. We have the tools and technology. But do we have the will to do what is necessary?