Anthropogenic drought monitoring using socio-hydrological modeling for surface water deficit: Lessons from Northern Taiwan

To illustrate anthropogenic drought, the comprehensive dual-system concept, which formalizes pathways and socio-hydrological interactions, was introduced. To quantify this concept, a modified water accounting and vulnerability evaluation plus (WAVE + ) model that integrates factors such as return water from precipitation, local water stress robustness, and the risk of freshwater deprivation threshold (RFD threshold) derived from historical data was proposed. This process-based model provides regional cross-comparable scarcity and seasonal socio-hydrological water vulnerability patterns. The RFD and conditional water depletion index (CWDI) were derived from the modified WAVE + model to describe anthropogenic-hydrological drivers. By leveraging the dual-system concept and the modified WAVE + model, the proposed RFD-CWDI method effectively identified and evaluated the duration, intensity, and severity of anthropogenic drought events. The performance of the RFD-CWDI method matches or surpasses that of the improved multivariate standardized reliability and resilience index, a powerful product-based index used for the characterization of anthropogenic and socioeconomic drought. Moreover, the RFD-CWDI method simplifies the analysis of anthropogenic drought event cycles by combining the degree of water deficiency with dual-system vulnerability, distinguishing it from meteorologicalhydrological and hydrological-socioeconomic cycles. The dual-system and modified WAVE + model define dynamics and socio-hydrological interactions, and they provide a widely applicable process-based method, the RFD-CWDI method, for assessing anthropogenic drought events.