Wells in Greymyr Passes

There are three wells located near the entrances to the Greymyr Passes. This sketch illustrates the well at Midpass, but North and South passes also have wells. The wells maybe have been constructed by the Greymyrs, but since there don't seem to be any structures in their village, this seems unlikely. Also, as rock creatures, they wouldn't have much use for water.

On the 78th of Spring I found myself taking an impromptu tour of the passes, and I found no sign of any structures or civilization that might have constructed the wells. Perhaps the wells were constructed by some early inhabitants of Puddleby who were then driven out by the wendeckas that infest the passes?