See https://www.cuahsi.org/data-models/portals/ for a web-based version of this list, which contains links to web portals and/or websites with data or links to data on water resources (including flow, water quality and integrated water resources management). Feedback or information regarding additional portals can be sent to help@cuahsi.org.
For Version 1 of the list, see: https://doi.org/10.5281/zenodo.495080