2nd Sunday market of the game is when I noticed the issue. I bought the Heavy fishing rod and though I would go to the ocean to fish, and there was no water in the rivers, ocean, etc. The boats were floating in mid air and the "beach" was covered in seashells. I also recently completed the teahouse, but not 100% sure if it was before or after the water disappeared. Makes for fun screenshots though.

I had a similar experience. I believe the rivers ran dry in the start od the summer, because since summer 3rd the waters have vanished. I still can swim tho, its kinda funny

i have this problem as well, the water of the rivers and ocean disappeared on my main file. starting a new day doesn't bring them back. reloading a save, going back to the main menu, quitting to desktop, or reinstalling also doesn't work. however starting a completely new file does, which i don't want to do quite yet i haven't completed the teahouse yet, and my earliest file only has it half completed. the water disappeared for me on spring 17th which is when i noticed, but it might have disappeared on the 16th (i accidentally immediately slept when i loaded my SPR16 file so i couldn't check). i can't swim or fish in any place that would normally have water, but i can walk/bike on the dry river/ocean floor

Just had the water disappear again, water was there, went into the caves, passed out, and when I woke in the morning, all the water was missing (rivers, etc).

This just happened to me, I can stand on the bottom of the riverbed. It happened on like the last Wednesday of Spring.