The data in the file “hydrogeology_Mekong_Vietnam.nc” (in NetCDF – format) contains the 3D voxel model of the hydrogeological units for the unconsolidated sediments in the Mekong delta, Vietnam. The variable “hydrogeological_unit” represents the aquitards (uppercase), while the lowercase codes denote aquifers. The coding follows the Vietnamese nomenclature and is explained the accompanying paper. The data in the file “TDS_Mekong_Vietnam.nc” (in NetCDF – format) contains the 3D voxel model of: variable called “Etype_estimate_TDS”, representing the average concentration (in g/L) of Total Dissolved Solids (TDS) variable called “Probability_TDS_smaller_1g_L”, representing the probability of TDS < 1g/L variable called "fresh_brackish_saline" in which each voxel is classified as containing fresh (TDS < 1g/L, code=1), brackish (TDS 1-3 g/L, code=2) or saline (> 3g/L, code=3) groundwater . for each hydrogeological unit of the “hydrogeology_Mekong_Vietnam.nc file. Only the deepest units (N13 and n13) are not included due to lack of basic data. The coordinate system is WGS84m - UTM 48 N. The voxel size is 1000 m x 1000 m x 5 m. The accompanying paper (preprint, by the same authors) can be found at https://doi.org/10.5194/essd-2021-15 and is called "The 3D groundwater salinity distribution and fresh groundwater volumes in the Mekong Delta, Vietnam, inferred from geostatistical analyses"

This version includes fresh, brackish, saline groundwater classification in the TDS model. Hydrogeological model is not changed