A frame of understanding to better link nature-based solutions and urban planning

Reinforcement of the concept of nature-based solutions in urban environments calls for their better introduction and linkage into urban planning. The paper is focused on the relationship between nature-based solutions and spatial realities, based on reciprocity among natural processes and urban patterns, emphasising the recognition of using and mimicking natural processes in urban environments. A classification framework as a form of knowledge aggregation is suggested. A matrix that simultaneously addresses the role of natural processes in nature-based solutions and the ability of such processes to deliver results for improving urban environments is proposed. Accordingly, there are three characteristic groups of solutions suggested, (1) those only using natural processes, (2) those using and mimicking natural processes and (3) those only mimicking natural processes, which implementation potentials are commented against four different types of urban patterns, to show what group of the nature-based solutions may best suit any type of spatial agglomeration. Beside green infrastructure as currently the most often addressed manifestation of nature-based solutions in cities, the paper reflects also on the physical processes as inevitable parts of nature. In relation to urban planning, sites and their characteristics are seen as a crucial aspect of nature-based solutions. The arguments are built upon exhaustive literature and case studies review, resulted in the matrix showing the matching relations among nature-based solutions and societal challenges aiming for better urban environment. Additionally, there are also sets of recommendations for bridging the policy-implementation gaps to bring nature-based solutions closer to urban planning, suggested.