SECURE-NBS: A conceptual framework for integrated nature-based flood risk reduction

Nature-based solutions are increasingly promoted for flood risk reduction. Yet, existing studies lack a unifying framework capable of explaining how spatial structure, scale, equity, governance, and socio-ecological feedback jointly shape nature-based solutions performance. This paper introduces the SECURE-NBS framework—Scalable and Equitable Conceptual Understanding for Risk Evaluation through nature-based solutions— a novel conceptual approach that integrates the key features and aspects of nature-based solutions that reshape flood risk. SECURE-NBS conceptualizes nature-based solutions outcomes as co-produced socio-ecological processes in which benefits and trade-offs interact dynamically across spatial and temporal scales. By embedding equity as a structural determinant of vulnerability and treating scale as a relational property, the framework highlights how nature-based solutions can reduce, redistribute, or reproduce flood risk under different conditions. The framework advances flood risk scholarship by moving beyond linear cause–effect reasoning toward a dynamic, feedback-based understanding of nature-based solution performance. SECURE-NBS provides a scalable foundation for comparative empirical research, spatial modeling, policy evaluation, and adaptive planning in urban, coastal, and watershed flood risk assessment and planning.