I’ve heard that bodies of water boasting high salinities tend to turn red due to seasonal algae blooms. I have a river in a fantasy setting I’m working on that’s blood red year-round, and I want to kind of subtly hint to the readers that this is the actual reason the river is red, rather than the local juju and other superstitions (because medieval folk probably wouldn’t understand the idea of microscopic organisms turning the water into blood).
However I’m not too familiar with the details of these blooms or what environmental factors can permanently cause a river to become highly saturated with salt. My immediate, most brute-force caveman idea was to have the waterfall that feeds into this river cut through what amounts to a hill or a small mountain of salt, giving it the nickname “Leech’s Knee” (with the angular waterfall being a bent knee and the red water below being the blood flowing from it after one has plucked or salted a leech). I don’t know if this would actually work however, or if there is a more elegant solution.
Can anyone lend me a hand?