AWARE historic and 2024 characterization factors for Spain

Water scarcity is a growing concern, especially in regions with Mediterranean, arid, and semi-arid climates. Conventional indicators often use historical data, limiting accuracy under current hydrological changes. This study aims to develop an improved methodology for water scarcity assessment in Spain, enhancing the AWARE approach by integrating current reservoirs data and refined demand estimates to increase spatial and temporal precision. he AWARE-based methodology was adapted for Spain by incorporating up-to-date reservoir storage data and demand values sourced from official hydrological plans. The assessment operates at the granularity of Demand Units, the most resolved administrative partition in Spanish basin management, thereby permitting high-resolution spatial disaggregation. Characterization factors reflecting water scarcity were evaluated for each Demand Unit in annual time steps, superseding the static application of historical averages. This methodological refinement facilitates differentiated calculation of local water demand and supply, allowing a temporally dynamic and spatially resolved portrayal of water stress across the national territory. Application of this advanced methodology to 2024 data reveals an average increase of 8.3% in water scarcity characterization factors relative to historical baselines. However, this national mean conceals significant regional contrasts: certain regions experienced improved availability, while others exhibited intensified drought conditions, highlighting entrenched polarization in Spain’s hydrological landscape. The dynamic integration of supply and demand enhances the accuracy and adaptability of scarcity metrics compared to static approaches, facilitating improved identification of at-risk areas and underpinning environmental impact assessments with locally relevant evidence. The developed methodology offers temporally responsive and spatially resolved water scarcity characterization factors tailored for the Spanish context, providing a robust tool for informed environmental assessments and sustainable regional water management. Given its modular and data-driven structure, this framework demonstrates strong potential for replication and adaptation in other regions facing similar hydrological challenges, contributing to the advancement of globally applicable water scarcity assessment practices.