Could there be a plausible way to have a freshwater river that sources water from a saltwater ocean? By plausible I mean by means of everyday, scientifically-sound, boring-ass reasons, so no magic.
I am not a scientist, and do not know anything about rivers. Please help.
idk about fresh sourced from salt, but Brackish water (in between) can occur in different ways including even subterranean connection to an ocean
https://en.wikipedia.org/wiki/Brackish_water#Brackish_water_habitats
https://en.wikipedia.org/wiki/Anchialine_pool
https://en.wikipedia.org/wiki/Cenote#Freshwater/seawater_interface