Shattered Kingdoms

That's irrelevant to the point.

You can never "drown" on the surface of the water, though you could conceivably die by failing a bunch of swim checks and taking dmg from "swallowing a mouthful of water." You can't even drown in the parts of the deep ocean where it says the water is too turbulent to swim here (though you must fly over it and land).

In a sense, choking to death on mouthfuls of water and dieing while in a river is drowning though...

All those of Pyrathia can doggy paddle indefinetly.. even if they are magically sleeping.

Or someone who knew which way the river would flow and thought they'd save themselves the sleep-time (red stag going into the empire, anybody?)

Never try to cast word of recall if drowning, because you'll be unable to cast after a certain point and then most certainly die. Quaff or regular recall for the win!