Temporal and Spatial Patterns of Groundwater Drought in the Bruna River Catchment, Italy

Groundwater acts as a vital buffer for human activities, offering resilience against environmental, economic, and social challenges. However, the depletion of groundwater resources intensifies these challenges, particularly in Mediterranean regions where water resources are already under significant stress.

This study investigates groundwater drought dynamics in the Bruna River catchment in Tuscany, Italy, with a focus on the temporal and spatial patterns of drought and its attribution to climate change. The analysis employs various hydroinformatics approaches, including the Standardized Precipitation Index (SPI), Standardized Groundwater Index (SGI), a threshold-based method, and the Combined Drought Index (CDI), which integrates precipitation, soil moisture, and vegetation data to monitor agricultural drought, offering early warnings and identifying areas that are either affected or recovering. Furthermore, a SWAT+ gwflow model is being developed to explore drought attribution using both factual and counterfactual climate datasets.

Preliminary findings highlight obvious temporal and spatial drought patterns, even when utilizing short time series. The SGI exhibits strong temporal correlations with SPI12, SPI24, and the monthly threshold Q20. Moreover, SGI demonstrates good temporal and spatial alignment with CDI, underscoring its utility in groundwater drought assessments.

Future efforts will focus on finalizing and validating the SWAT+ gwflow model by calibrating it against observed data and performing sensitivity analyses. The validated model will facilitate an in-depth exploration of groundwater drought attribution by comparing outcomes under factual and counterfactual climate scenarios. These analyses aim to enhance the understanding of groundwater drought, which can inform water resource management and policy decisions.