Question for Holzer Agroecology -- Bubblers

I am wondering if you can elaborate on how to construct a bubbler?
Sepp Holzer's latest book shows some pictures of a group making one, but offers no explanation on how it functions.
I can almost figure it out from the pictures, but not all the way.
Thanks!

p.s. for those who may be unsure of what a bubbler is, it is in the videos of the Kramaterhoff. It is the vertical log with water streaming out a branch and into a hollowed out log trough. Those are so cool!

A bubbler is using the underground water. It is very important for it to be built in the right place. There are too many variables to be able to accurately describe on a forum but this is something we will be covering in the seminar. There have been many times that Sepp has corrected supposed "water experts" about where there is and isn't underground water.

Judith, Johnny, Zach and Team Holzer AgroEcology