IIRC, it is between 4 and 5 feet. Not deep enough to safely dive and not over my head (I'm 5'4'').
There is no additional quiet pool - just the one feature pool. (I'm not counting the ocean, even though the beach is generally very quiet (as far as people go, anyway, LOL).
Given that Disney's original plan for VB was MUCH larger, with a whole lot of timeshare units (like bldgs 12, 14 & 15) accross the road, perhaps a "quiet" pool was enisioned in the original plan; but when the resort did not sell as well as hoped, they cut that off along with all the units on the other side of A1A (or even the nonexistant Building 11 where the citrus garden is now).