Green and blue infrastructures for the regeneration of European metropolitan cities. Resilience practices in French Métropoles

The issue of sustainability has stimulated new ways of action, not only in terms of defense and preservation of the resources, but also in terms of proactive urban and territorial regeneration strategies (EC, 1999; EC, 2007). These strategies are reconciling two separate disciplinary goals (Talia and Sargolini, 2012): the reduction of the use of non-renewable resources, and the enhancement of common goods as drivers of a sustainable development and of the settlements reconfiguration quality (Ricci, 2014; Gasparrini, 2015). Therefore, European metropolitan cities have required a complex and an integrated strategy that merges an eco-landscape perspective, as well as morphological, functional and infrastructural ones. In this context, the most advanced national and international debate overcomes still strongly sectorial approaches and heads toward new urban planning disciplinary boundaries with landscape and environmental issues (Gasparrini, Gabellini and Rossi, 2014). In this context, the issue of urban resilience is considered a relevant operational concept, but also a significant collective value (Toubin, 2012). In fact, the development of regeneration projects into resilient strategies can lead the city toward a new urban system that provides innovative social, cultural, economic and environmental answers to global changes, through new procedures able to renovate governance processes and to support metropolitan governments. New partnership-based procedures as well as practices held by the community in order to face the problems of degradation and foster urban resources enhancement, including valorisation of historic heritage and landscape, highlight new research and experimentation paths. Many recent urban and territorial strategic plans and visions from different European contexts are emblematic cases of integration between urban and ecological-environmental issues through the construction of joint green, grey and blue networks, in many case designed as real infrastructures, at different scales. Among the various national contexts, France is certainly one of the most interesting frameworks on these issues since the recent national reforms and planning practices have stimulated the construction of sustainable and resilient metropolitan models.