Blue-green infrastructures and groundwater flow for future development of Milano (Italy)

Milan has always been considered a city of water due to the presence of a network of natural and man-made canals, lying on one of the most important Italian aquifer system which has been heavily exploited for public and industrial supply, but the future use of this resource still has to be decided. The rate of abstraction decreased of more than 30% since the 1970 (3.5 x108 m3/year on 1975 to about 2.3 x108 m3/year on 2016), with the number of inhabitants, the diminished per capita consumption and the decommissioning of industrial activities. This resulted in a groundwater rebound causing flooding of underground structures. Climate change scenarios project that urban regions will be exposed to extremes of precipitation and temperature, increased storm frequency and intensity. In recent thinking, portfolios of “blue-green” technologies and infrastructure (connected network of multifunctional, predominately unbuilt, space that supports both ecological and social activities and processes) combined with conventional “grey” infrastructure have been identified as best practices for achieving greater urban sustainability and resilience. In this context, a steady-state groundwater flow model was calibrated on a monitoring dataset and used to evaluate the impact of a blue-green infrastructure at the urban scale. The development of a continuous network of wells withdrawing water from the unconfined aquifer are placed along a ring linking the dismissed rail yard areas which will undergo significant urban developments in the next years. Various scenarios were simulated in order to evaluate the multiple functions of such system:(i) blue-green infrastructure …