# Comment posted to https://www.youtube.com/watch?v=Z8LvkbGSXNw
# by @megalithhunter

Elaborate structures built over and around natural springs are known around the world.   The nuraghi in Sardinia often have a well inside.  The Osirion in Egypt seems to have been mainly a reservoir dug down to the water table under the Giza plateau.  The "communal rooms" at Göbekli Tepe and Karahan Tepe look more like water cisterns than anything else.

So, unless hard dating says otherwise, I would guess that the well was dug first, for the simple purpose of providing water all year round.  That made it a focal point for people in a few km radius.  The well would surely have some permanent cover to keep the water clean etc.   Thus when those people decided to build the dolmen, for religious or whatever reasons, building it over the well was a natural decision.