Hello, and welcome to OSM.

a dam is this https://wiki.openstreetmap.org/wiki/Tag%3Awaterway%3Ddam
Probably you wanted map a man_made=water_well https://wiki.openstreetmap.org/wiki/Tag%3Aman_made%3Dwater_well or, for animals, a amenity=watering_place ? iD editor sometimes doesn't suggest the right tag. I would suggest to familiarize with the OSM tags looking at the wiki section.

Cheers,
   Alessandro