Groundwater time-series analysis supporting urban underground infrastructures management: the Milan city (Italy) case study

In recent years, a strong interaction between groundwater and underground infrastructures has emerged, determined by a significant employment of subsurface in urban planning. Numerical models are essential to manage this problem, but their construction is time and cost consuming. Groundwater time-series analysis can represent a valid complementary approach, as an extensive approximation of the geological and boundary conditions is not required, even if providing insights into the hydrogeologic system. Thus, for Milan city, in order to identify the potential variables affecting the water table levels of 95 monitoring wells (MWs) of the shallow aquifer, occupied by numerous underground infrastructures, data-driven techniques were adopted to analyse groundwater time-series. The study covered the period 2005-2019. Four management areas (MAs), possibly representing future territorial units with specific groundwater management policies, have been identified. As for underground infrastructures, public car parks have been classified in a) not submerged, b) at risk or, c) submerged at different groundwater conditions, allowing to propose for each MA targeted guidelines for constructing new car parks. This approach enabled to improve the urban conceptual model and could help the stakeholders in designing a futureurban underground development, also considering groundwater aspects.