Urban flood risk management needs nature-based solution from social-ecological system perspective

Abstract People-nature interdependencies in the social-ecological system (SES) are fundamental to coping with urban flood risks. Nature-based solutions (NbS), a holistic tool considering the people-nature interdependencies, have been advocated widely for urban flood risk management (FRM). However, how NbS has been used from SES perspectives in urban FRM is still not well elaborated, which refers to how NbS contribute to SES factors, processes, and effects? and what SES approaches may support NbS design, implementation, and governance? Therefore, this study first conducted a systematic review of ecological measures in urban FRM during 2000–2022, which showed an imbalance distribution of global knowledge, divergent linkages with social and ecological benefits, and growing insights from SES perspectives. According to the proposed conceptual framework, NbS’ contributions to urban FRM are explained by three dimensions: integrating socioeconomic and ecological factors, coupling social and biophysical processes, and identifying potential tradeoffs/synergies. However, inadequate understandings of NbS’ resilience, effectiveness, and synergy are still key challenges in existing studies that might hamper their contributions to both people and nature. Hence, SES approaches that leverage NbS in future FRM are suggested based on the conceptual framework, including multiple-scale flood resilience assessment, process-based effectiveness modeling, “win-win” effects prediction, and monitoring. We hope that urban FRM can leverage NbS through SES approaches to jointly achieve flood risk mitigation and adaptation, biodiversity protection, and human well-being in the sustainable and resilient pathway.