Linking water footprint and social vulnerability: a sub-regional input–output framework for assessing multiple dimensions of water scarcity

Freshwater scarcity and unequal exposure to water-related risks are increasingly recognised as constraints on sustainable development. However, most water footprint assessments remain primarily volumetric and spatially aggregated, limiting their ability to diagnose how hydrological pressure, environmental stress, and socially differentiated impacts are redistributed within interconnected regional economies. This diagnostic gap constrains the capacity of existing approaches to inform subregional and basin-level governance. This study develops a territorially coherent hydro-economic framework that integrates multi-regional input–output modelling with spatially explicit indicators of hydrological pressure, environmental stress, and social vulnerability. Applied to 48 Local Labour Systems in Tuscany (Italy), the approach jointly quantifies production- and consumption-based volumetric water demand, scarcity-weighted impacts, and socially differentiated exposure across intra-regional supply chains. The results reveal pronounced internal asymmetries. Production-oriented territories generate a substantial share of regional water demand while experiencing disproportionately high environmental stress and social vulnerability, even where total water use is comparable to neighbouring areas. Conversely, consumption-oriented territories act as net importers of virtual water, redistributing pressure and impact to more hydrologically constrained and socially fragile locations within the same regional economy. By explicitly tracing the internal redistribution of hydrological stress and social vulnerability through economic linkages, the framework extends conventional volumetric assessments and provides a diagnostic basis for governance strategies that address not only efficiency, but also equity and the territorial distribution of water-related risk.