Drought risk assessment in Mediterranean agricultural watersheds: A case study in Central Italy

Mediterranean watersheds are expected to face increased and more severe drought events due to climate change. Urgent action is needed to shift from a reactive approach to a proactive one, for which drought risk assessment is fundamental. Nevertheless, the current methodology to calculate composite risk indicators is still debated, undermining the overall robustness and validity of drought risk assessments. Furthermore, the diversity of socio-ecological contexts, spatiotemporal scales, and data availability hamper the homogenization of assessment methods. We present a complete drought risk assessment methodology, applied to the agricultural systems of five Italian coastal watersheds, introducing a simple robustness evaluation method to validate the assessment tool and archetype analysis to link the outputs with adaptation strategies. Forty-two (42) indicators were included to represent hazard, exposure, and vulnerability. Past and future drought hazards were estimated considering multiple types of droughts with data from public observatories.The results show highest hazard for the southern part of the study region, highest exposure in the coastal and high-value wine producers’ municipalities, while vulnerability patterns are less clear. Major adaptation efforts should target specific watersheds of the Grosseto province, which has the highest projected drought risk. Archetype analysis was then used to suggest possible context-specific adaptation strategies. The proposed methodology, with the integration of a robustness evaluation and the archetype analysis, represents an advancement toward shared and homogeneous guidelines in state-of-the-art drought risk assessments.