HCDN US daily runoff data
The HCDN dataset
contains daily unoff data from the US
only over the period 1874-1988. In general hydrologists are not keen to share
their data, and with the exception of the US it is almost impossible
to get hydrological data for use in the Climate Explorer.
This is the best I could find a few years ago, please contact me if you know of a more
extensive or up-to-date dataset.