I think that the water of rivers should be much more transparent because it is impossible to know whats in front of you, you basically are doing a jump of faith.
I know about the depth bars in the map, but they arent that useful. Sure, they can give you an overall path, but unless you are switching to that map every 5 secs and check your situation, you cant know if your overall has a trench or you deviated 5 cm to the left.