Hi,
You could use Events to cover them with perhaps water spray.
I have created some.
The tileset has some blanks in it right now though, I will share the tileset once completed.
(It also contains RPG Maker XP items, so not everyone can use the Graphics without owning it).
This shows how I deal with the issue, kind of distracts from it rather than removes the issue though:
And might give you ideas on how to get around it.
Turned on Notifactions will be interesting to see what others suggest as this issue really annoyed me.
If you do try my demo please give it a review.
If you do I I will happily create you a seperate Waterfall spray Event, created by me that you don't have to credit me for.
LoS