This was one of the most amazing barrows I have ever seen. Ive never seen one holding its water in such a tidy and aesthically pleasing way. Looking at the main ring-barrow here it does add to the argument that some barrow/monuments may have used water features to make them more dramatic. I think in this case you will agree it does look pretty impressive.
I presume that the water doesnt stay here year round. This barrow is located alongside a path that can be accessed by driving up the hill to the right coming from the ferry (towards Doonagore tower house). There is a warning sign for dangerous cliffs and this barrow are pretty close to the path/cliffs. You can get a view down to the axe factory from here.
The other two are about 300m farther to the east.