Because I served, I will resist
The wooden fountains are a Kickstarter exclusive. That's why there's no reference to them on the box or the regular game materials.
Regarding storage, after assembly I was able to stash two each in each of the two spaces between decks in the storage area for Alhambra The Card Game and the remaining two in the dice cup.
Not exactly exclusive. Both the fountains and board were part of the anniversary edition published a few years ago.