GloWS: A Global Large-Sample Watershed Synthesis Dataset Empowering Hydrological Simulation and Future Projection

Modelling how rainfall becomes river flow requires long records from many catchments at once, yet the collections available either cover a single country in depth or the whole world thinly, and almost none carry any information about the future. GloWS assembles 23,029 river basins from 24 international, national and sub-national archives into one consistent collection, each gauge screened individually and its position checked against satellite imagery before the record was accepted. Every basin comes with its watershed outline, the flow statistics used to characterise droughts and floods, fourteen meteorological variables, land cover, soil moisture and snow storage, and static descriptors such as climate class. The dataset then extends each catchment forward in time: nine daily variables from 22 climate models under four socioeconomic pathways, bias-corrected to the individual watershed and running to 2100, combined into a single ensemble scenario by weighting the models on skill and independence. The same catchment can therefore be studied on what was measured and on what is projected without stepping outside the dataset.

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