Urban Metabolism Analysis as a Support to Drive Metropolitan Development

The research concerns the topic of urban metabolism as a method to orient policies at urban/territorial level. As suggested by other researches, a metabolic analysis of the urban environment could help planners and managers to improve resource use in cities; to reduce environmental degradation; to identify environmental impacts of energy, material, and waste flows; and to isolate problematic areas in need of attention. The metabolic framework implies a deep knowledge of the main local input and output flows of energy and matter, with detailed energy and environmental accountability. There are thus some difficulties to develop a comparative metabolic analysis of more territories. The research was developed within a wide national academic study in several Italian urban regions and focuses, in particular, a square territory of 100 × 100 km2 around the centre of Milan, in northern Italy. The main local input and output flows are analysed for each municipality (904 in total) considering the available databases. Urban metabolism is investigated by the application of a fuzzy logic model, which consists in a hierarchically organized system of variables and their fuzzy evaluations using a cascade of Takagi-Sugeno models. The overall structure of the model, the definition of the subsystems (built environment, people mobility and socio-economic context in relation to quality of life), the set of the indicators, the adopted benchmarks and the levels of importance of the variables are calibrated on the actual context of application. The model provides as synthetic outcome the UEI (urban efficiency index), which is very clear from the point of view of interdisciplinary approach. Therefore, this kind of index can support policy makers, public utilities, urban designers and other stakeholders in defining strategies for improving the performance of the different urban areas looking at their features, weaknesses and potentialities. Further, the structure of the UEI underlines the important role of utilities and their effects. This study represents an important occasion for applying the metabolism approach to a well-known territorial context and compare several territories at once.