Fresh ideas on modeling water demand and allocation in Global Hydrological Models

Global hydrological models are essential tools to address the increasing challenge of global water scarcity. However, current models often rely on simplistic assumptions for sectoral water allocation, limiting their ability to capture real-world complexities such as prioritization and competition among water uses. This paper introduces a theoretical two-layer framework that distinguishes between essential and prosperity water demands across key sectors, including domestic, livestock, industry, irrigation, and environmental flows. Essential demands represent baseline requirements to prevent severe socio-economic and ecological impacts, while prosperity demands encompass more discretionary uses that can be curtailed under scarcity. The framework is coupled with a ’traffic light’ system inspired by the drought management practices at the Catalan Water Agency to guide allocation decisions, dynamically adapting to water availability. This approach, if implemented or further developed, can significantly enhance the realism of global water models, providing actionable insights for sustainable water resource management.