Urban flood risk management needs nature-based solutions: a coupled social-ecological system perspective

A growing number of Nature-based Solutions (NbS) has been advocated for urban flood risk management (FRM). However, whether NbS for FRM (NbS-FRM) achieves both social and ecological co-benefits remains largely unknown. We here propose and use a conceptual framework with a coupled social-ecological perspective to explore and identify such "win-win" potential in NbS-FRM. Through a scoping-review we find that ecological FRM measures are unevenly distributed around the world, and those solely targeting flood mitigation may have unintended negative consequences for society and ecosystems. In elaborating this framework with evidence from the reviewed studies, we find that NbS-FRM has the potential to provide both social and ecological co-benefits, with remaining gaps including a lack of resilience thinking, inadequate consideration of environmental changes, and limited collaborative efforts to manage trade-offs. The proposed framework shows how to move forward to leverage NbS for equitable and sustainable FRM with improved human well-being and ecosystem health.