You could be right, i was just looking at the lack of a status message saying "thursty" :/
EDIT:
Ok i had another look, I think your problem is that you only have 3 barrels of booze, and at any one time there would be more than 3 dorf's who need a drink, dorf's don't exactly line up an an orderly queue so when someone needs a drink and all the barrells are occupied they assume there is nothing to drink and go back to work for a while, also factor in the waiting time for access to a barrel, if one guy on the corner of the map notices a free barrel, he basically claims it and it becomes forbidden to use untill he hauls his ass across the map to it,despite the fact that 20 dorf's could quaff from it in the meantime...
I suggest that your water source might be similar, maybe make a narrow channel running along side it with lots of watersource zones along is so lots of dorf's can use it... and your pools might be murky and nobody wants to use em.
... but yeah anyway, you need WAY MORE BOOZE!
EDIT 2:
Your river water and murky pools seem undrinkable (when you make a zone area over water if it shows 0 next to water source it's undrinkable), however your cavern water is good, i zoned a huge water source on your cavern lake (remember to include the ground your guys will stand on to drink) and literally 120 dorf's stampeded down there (eventually, it's a fair hike) to sate their thirst.