Exploring nature-based adaptation solutions for urban ecohydrology: Definitions, concepts, institutional framework, and demonstration

In this study, nature-based adaptation solutions (NBaS) are presented, and their relevance to urban Ecohydrology is explained. Two lines of work define this chapter: the first is a conceptual discussion of definitions and introduction of NBaS along with their positioning with respect to the French, European and International scales. Then, the NBaS-Ecohydrology nexus was addressed with an emphasis on urban environments and urban related NBaS. The second line of work consisted of reporting quantitative evidence on the efficiency of green roofs as NBaS at the interface with Ecohydrology. For explaining nature-based adaptation solutions (NBaS), the nature-based solutions (NBS) concept was first introduced and the transition to NBaS was explained. The urban environment was chosen since climate change and water management challenges are urgent manners to be addressed within. The urban context was also chosen since it is shaped by the dynamic relationship between ecological, socioeconomic, and physical systems, hence its relevance to ecohydrology. As the latter deals with modified and/or novel landscapes (among others), the urban system is highly relevant. To that end, urban ecohydrology was introduced. Since this discipline particularly focuses on storm water management in cities, green roofs were chosen as the target NBaS of this study. The reasons behind this choice are based on the ecological potential of green roofs, their hydrological properties, their climate regulation potential, use for storm water management and their overarching nature across water, and biota and engineered systems. Accordingly, insights from literature on the efficiency of green roofs were then given. Quantitative evidence on their efficiency was then reported from a storm water management angle. On the basis of the above-discussed elements, this study demonstrated the efficiency of NBaS (here green roofs) for (urban) Ecohydrology.