IMPLEMENTATION OF NATURE-BASED SOLUTIONS (NBS) FOR URBAN HEAT ISLAND (UHI) MITIGATION RESTORATION OF GREEN BROWNFIELDS IN THE CITY OF MILAN

The objective of this work was to contribute to the recovery of a disused green area in the municipality of Milan, located in one of the most vulnerable areas, through the implementation of nature-based solutions (NBS) to mitigate urban heat island (UHI) problems. After an initial overview of climate change issues and the problems caused by urban heat islands (UHI), an in-depth analysis of NBS solutions was carried out with the aim of understanding which of them were most suitable for the project, but also how they could be economically evaluated. Both the technical implementation and subsequent maintenance of NBSs were considered, as well as the economic return and environmental and social benefits. To identify degraded green spaces in the city of Milan that could benefit from NBS intervention, a vulnerability map was developed based on three macro variables: environment, society and infrastructure. The map was created using QGIS software and the Analytical Hierarchy Process (AHP) technique was used to weight the variables using SuperDecision software. Based on this map, it was possible to select an abandoned area where it was decided to implement urban reforestation as an NBS solution, with the intention of providing cooling benefits for UHI mitigation and also to provide a green area for citizens in a vulnerable context. Once the NBS to be implemented was identified, all the cost items for its implementation were analysed with reference to the 2024 Prezzario of the Lombardy Region. The cost analysis continued with the maintenance items for the years following implementation, calculated for a 20-year period. Finally, in order to estimate the potential benefits generated by the implementation of NBS, a literature review was carried out, followed by a discounted cash flow analysis (DCFA) to quantify the ecosystem services (ES) generated. This work demonstrates the importance of brownfield redevelopment in large urban contexts, such as Milan, by incorporating solutions such as NBS, and how these micro-interventions can potentially benefit the population and the environment by mitigating increasingly urgent problems.