Spatio–Temporal Dynamics of Groundwater Levels in the Piedmont Po Plain (NW Italy): Impacts of Climate Change and Land Use

This study analyses spatio–temporal trends in groundwater level (GWL) across the Piedmont Po Plain (NW Italy), aiming to assess the impacts of climate change (CC) and human drivers on regional groundwater systems. Data were collected from a network of automated monitoring wells over the period 2010–2022, supported by meteorological records from regional weather stations. Results indicate a widespread decline in GWL, with an average of −4.32 cm/y and a maximum of −16.74 cm/y in the time period observed, particularly in recent years. These trends align with decreasing precipitation patterns observed in the region. However, deviations from this general behaviour are also identified. More specifically, local land use practices—specifically rice field and irrigation—may be artificially maintaining GWL. Moreover, hydrometric level data from the main rivers of the region were analysed to evaluate potential interactions with GWL variations. This comparison showed that, in general, no clear correspondence exists between river level fluctuations and groundwater dynamics, except in cases where monitoring wells are located within 50 m of a river channel. In addition, this study was compared with a previous study on the same area concerning temperature variations in groundwater, which allowed for an understanding of both the qualitative and quantitative impacts of CC on the groundwater in the area. The combined analysis highlights the interplay between CC and anthropogenic influences, emphasising the need for integrated groundwater management strategies that account for both climate variability and land use dynamics. Furthermore, the seasonal analysis of GWL revealed a clear hydrological cycle shaped by irrigation activity. In particular, the occurrence of GWL peaks during summer (irrigation season) confirms the role of irrigation in controlling aquifer behaviour in agricultural areas. The absence of a general correlation with river stage, combined with the occurrence of GWL peaks during summer (irrigation season), confirms that irrigation is the main driver of GWL fluctuations over the study period. This finding is critical for the accurate interpretation of groundwater responses and for developing effective and sustainable water management strategies in intensively cultivated regions.