Most dog historians and breeders agree that the Irish Water Spaniel is a mixture of many other spaniel breeds. But Irish folklore tells us quite clearly that this dog descended from the ancient Dobhar Chu.
It is possible that the Irish Water Spaniel does indeed derive from the Dobhar Chu, however, the breed was subsequently mixed with other spaniels. But these are only the assumptions of the breeders, since the person who made the breed the way we know ...