Global Specific Yield Dataset for Groundwater Storage Estimation

The dataset integrates several authoritative hydrogeological databases, including the WHYMAP Global Hydrogeological Map, the British Geological Survey (BGS) African Aquifer Map, the Geological Survey of Canada (GSC) Asian Hydrogeological Database, and aquifer datasets from the United States Geological Survey (USGS) (Table S1). Through multi-source data integration and spatial standardization, these heterogeneous datasets were harmonized and generalized into five major hydrogeological categories representing dominant aquifer and surficial sediment types.Based on this hydrogeological classification framework, a global specific yield dataset was developed. Representative specific yield values were assigned to each aquifer type according to widely used hydrogeological references and engineering manuals, including the Levee Engineering Handbook and Groundwater Contaminant Transport Modeling. The assigned values are as follows: coarse-grained sediments (e.g., sand and gravel) – 0.18; fine-grained sediments (e.g., clay and silt) – 0.13; loess aquifers – 0.14; fractured bedrock aquifers – 0.06; and karst aquifers – 0.01. Using these parameter assignments, a global map of groundwater specific yield distribution was produced.