I have tried multiple ways to fill a barrel from a river and other mediums back and forth. Here is what I know you can do with a barrel.
You may create and pass tanning fluid from a barrel to tanning tubs.
You may create and pass rose tanning fluid from a barrel to tanning tubs.
You may fill gardening pots 1 at a time while carrying a barrel over your head.
You may fill oil troughs with a carried barrel.
Other than those when using water you must still go to the lakes and the rivers your used to and fill them 10L at a time.
