Green Spaces Accessibility in Historic Urban Centres

Considering the fragility of urban systems in the face of increasing risks of climate change, one of the key issues in recent decades has been the adaptation of urban structures to achieve improved resilience. The integration of Green Infrastructures (GI) into the built environment plays a key role in this process as natural components can provide a more flexible and integrated answer to many stresses and challenges affecting urban areas. However, existing GI strategies are mostly based on large-scale interventions, such as greenways and new parks and they have major limitations when interfacing with compact urban fabrics. Focusing on the case study of Milan, this paper aims to relate urban structural metrics and design criteria of Urban Green Infrastructures (UGI), to identify possible synergies. In particular, the dimensions of Permeability and Porosity are assessed to evaluate the UGI planned by the PGT Milano 2030 in urban areas with different morphological characteristics. The results mark the incompatibility between the current UGI strategy and the characteristics of the historic centre. The study then focuses on the historic centre of Milan, with the objective of identifying its margins of transformability to re-integrate natural components even in this part of the city. The potential of inner courtyards and private urban voids for the integration of GI in the historic centre is assessed proposing a prioritisation and grouping of courtyards, based on the UGI connectivity principle, to optimise possible future interventions.