Towards flood risk reduction: Commonalities and differences between urban flood resilience and risk based on a case study in the Pearl River Delta

Despite traditional measures to prevent disasters, climate change and urbanization increase flood risk. Thus, flood resilience has attracted increased global concern. Understanding the commonali-ties and differences between flood resilience and risk is arguably important for flood risk reduc-tion. However, these factors have been seldom reported in previous studies, and discussions on the role of flood resilience in flood risk analysis, assessment, and management are lacking. In this study, the association between flood resilience and risk is discussed using a case study in the Pearl River Delta. Flood resilience is quantified using a pressure-state-response (PSR) model, while flood risk is assessed based on the hazard-vulnerability framework and the extension catastrophe progression method. The implications of considering flood resilience in flood risk analysis, assess-ment, and management are proposed. The results suggest that the overall flood resilience (risk) in the study area is greater (lower) than that in the highly urbanized areas, and areas with low (high) flood resilience (risk) are mainly concentrated within the highly urbanized areas. Indices extracted from human society and highly related to human activities have the same attributes in both frameworks, while indices associated with climate and geography contribute to the two con-cepts differently. Flood resilience supplements the concept of flood risk, and can be incorporated into risk assessment as an index. Moreover, pre-disruption (post-disaster) measures should follow flood risk (resilience) assessment, and strategies that foster flood resilience should be included in flood risk management. This study provides references for flood resilience improvement and risk mitigation.

Automated summary

Despite traditional disaster prevention measures, flood risk is increasing due to climate change and urbanization. This has led to increased global concern for flood resilience. However, previous studies have rarely reported on the associations and differences between flood resilience and risk, and discussions on the role of flood resilience in flood risk analysis, assessment, and management are lacking. In this study, a case study in the Pearl River Delta is used to discuss the relationship between flood resilience and risk. The study quantifies flood resilience using a pressure-state-response model and assesses flood risk using a hazard-vulnerability framework and the extension catastrophe progression method. The results suggest that flood resilience complements the concept of flood risk and can be incorporated into risk assessment as an index.