Policy Evaluation of Flood Risk with Nature-Based Solutions in River Basin Cities

Abstract

Urbanized river basins are increasingly vulnerable to flood risks exacerbated by climate change, rapid land-use conversion, and aging conventional engineering infrastructure. In response, Nature-Based Solutions have emerged as a critical policy instrument for enhancing urban hydrological resilience while providing multifarious ecological and social co-benefits. This paper provides a comprehensive evaluation of current policy frameworks governing the implementation of Nature-Based Solutions in river basin cities. By systematically reviewing governance structures, institutional capacities, and regulatory mechanisms, the research identifies the fundamental barriers and enablers associated with scaling green infrastructure. Utilizing a multi-criteria policy evaluation framework, the study analyzes qualitative and quantitative metrics of effectiveness, efficiency, equity, and adaptability. The findings indicate that while localized implementations of Nature-Based Solutions demonstrate significant efficacy in mitigating peak runoff and enhancing urban biodiversity, systemic policy fragmentation and inadequate funding models frequently constrain broader basin-wide deployment. The research concludes that integrating these solutions into comprehensive municipal planning requires a paradigm shift towards adaptive co-management, long-term blended financing, and robust transboundary institutional cooperation. Strategic recommendations are provided to guide policymakers in optimizing flood risk management frameworks for sustainable urban futures.