Nature-based solutions and policy instruments towards an optimal urban design

Urban planning is crucial to promote resilience and liveability of cities in the face of current urbanization patterns and climate change challenges. Nature-based solutions (NBS) are viable alternatives to grey infrastructure, with multiple environmental, social and economic benefits and co-benefits, comprehensively contributing to the sustainable development goals. Despite their widely recognized importance, socio-economic dynamics are less studied – namely in simulation approaches. Additionally, they are rarely considered alongside policy instruments to either steer or potentiate the NBS socio-economic and urbanization impacts. Hence, the objective of this paper is to assess the effectiveness of several simulated NBS and policy instruments in different case studies with different socio-economic contexts. It aims to provide municipalities and policy-makers evidence to learn from and extrapolate expected outcomes based on urban characteristics. From a participatory approach perspective, the methodology included NBS co-design workshops with municipalities as well as NBS and policy instrument scenario simulations. Regarding NBS impacts, attractiveness has proven to be the most relevant characteristic, in combination with urban pre-greenness, size and/or location. Furthermore, NBS in combination with policy instruments demonstrated the potential to maximize NBS benefits and control urbanization processes, such as gentrification and urban expansion, namely though real-estate taxes, subsidies and zoning.