If you enjoy this bit of physics, and you're wondering if water flowing the "wrong direction" is something that happens in real life, aside from the other comme

If you enjoy this bit of physics, and you're wondering if water flowing the "wrong direction" is something that happens in real life, aside from the other comments about wind-induced counterflow, definitely look up the Severn bore[1], too, which is a tidal bore that makes the river Severn flow inland twice a day, with wave fronts that can be large enough for folks to "surf upstream". [1] https://en.wikipedia.org/wiki/Severn_bore https://en.wikipedia.org/wiki/Severn_bore