Here, you can find a list of portals offering free, open-source data, along with the relevant software necessary for processing this data. All the links below apply to the global data. If you are looking for regional data, please check the regional databases section.
H
– Seamless hydrographic data for global and regional applications. Free data on hydrowaste, lakes, rivers and basins worldwide. Additionally, the hydroAtlas is available there. Downloadable in Geodatabase and Shapefile format.