The Impact of Climate Change on Groundwater in the Piedmont Po Plain

The IPCC's 1992 First Assessment Report (FAR) identified climate change (CC) as a global challenge with non-negligible consequences. While visible effects, such as rising air temperatures (AT) and changing precipitation patterns, are increasingly evident, impacts on groundwater (GW) resources are often ignored despite their significance. This PhD thesis aims to fill this gap by studying the quantitative and thermal effects of CC on GW with a particular focus on a shallow aquifer in the Piedmont Po Plain (NW Italy). In the first part of the manuscript, through a comprehensive review of the existing global scientific literature on the subject, it becomes clear that CC affects GW, especially with regard to changes in GW levels (GWLs), changes in GW quality and changes in GW temperature (GWT), resulting in an embedded understanding of CC-GW interactions. Regarding the Piedmont Po Plain, statistical analyses reveal a general decline in GWL across the region, attributed to altered precipitation patterns and increased AT. However, some anomalies are present, such as positive trends in agricultural areas, suggesting specialised influences that require localised management strategies that address specific GW management needs. In addition, the analysis of GWT variations shows a positive correlation with AT, indicating the intricate interaction between CC and GW thermal dynamics. Moreover, a 3D model applied to the Torino metropolitan area was also used to predict future GWT variations based on different IPCC scenarios (RCP 4.5 and RCP 8.5) and to understand how to better manage the GW resources in an urbanized area. Finally, this thesis offers a new graphical method for dissemination purposes, using GWT “stripes”, for effective visualisation of GWT trends, aiding communication and understanding of the data by society. Thus, this thesis emphasises the vulnerability of shallow aquifers to CC and anthropogenic pressures, highlighting the need for GW management strategies that require continuous research efforts. Indeed, the thesis contributes to the broader understanding of the impacts of CC on GW, offering valuable insights for informed decision-making and sustainable GW management practices. It serves as a basis for ongoing and future research initiatives in hydrogeology at both regional and global scales.