Nature-based solutions for urban stormwater management: Experiences in Malmö and Copenhagen: A case study analysis on the decision-making process

Abstract: Nature-based Solutions (NBS) are one of the approaches to the regeneration of urban areas. These solutions are copied from, inspired by, or supported by nature. The solutions, ideally, result in multiple benefits to the society and environment. The examples of NBS measures for stormwater management are, including but not limited to, natural swale, retention ponds, and green roofs. Such measures have been successfully applied in Malmö, Sweden since the 1990s and recently been executed in the municipality of Copenhagen, Denmark. This research aimed to understand the transition from policy to the actual practice of integrating NBS measures into the stormwater management plans of the municipality of Malmö and the municipality of Copenhagen. It studied decision-making and planning processes for the integration at the city level of these two cities and the reasons behind their successful implementation by reviewing the literature and interviewing 14 stormwater management and climate adaptation professionals from both cities. The data gained from the studies were organised and analysed for better understanding three key issues: the initiation of integrating NBS, the process of integration, and how this process can be leveraged. The results point to the collaboration from various sectors and political support as the key social innovations which lead to the successful implementation of the NBS measures to the urban stormwater management plans. The suggested leverage points and strategies for scaling up the integration process include focusing on communication and knowledge transfer which could lead to the shift in the mindset of stakeholders towards stormwater management.