Performance assessment of the ecosystem services provided by urban Nature-based solutions: Focus on rainwater management

Abstract

Nature-based solutions (NBS) in cities are known to provide numerous ecosystem services that contribute to the well-being of city inhabitants and to climate change attenuation and adaptation. Common services provided by the NBS are urban heat island reduction, provision of habitat for biodiversity, rainwater management, indoor summer comfort, etc. To provide science-based arguments for the choice of the adapted solutions to a specific context, the assessment of those services is necessary. The aim of this paper is to review models assessing the service of rainwater management for three green infrastructures: green roofs, urban trees (stand-alone or micro-forest) and vegetated permeable pavements. The final goal of this work is to help improve the decision aid tools for the environmental assessment of the performance of buildings and districts. The characteristics of each model are presented and analyzed, in terms of robustness, parsimony and operationality. We for example compared the number of required parameters (e.g., plant species, substrate type and depth of green roofs, soil moisture, etc.), the availability of these parameters, etc. The multifunctionality of NBS (i.e., other services provided beyond the contribution to the rainwater management) is also considered in the analysis. In addition, as NBS are living systems, their specific needs (such as water and mineral nutrients), as well as the influence of the local context (e.g., climatic, topographic, cultural) are discussed. Finally, some paths for the implementation of the models into the decision tools are highlighted. The main challenge for the implementation in decision tools could be the harmonization between different expertises and stakes.