From the site I quote from:

The nymphaeum, probably built in the second half of the 2nd century AD, stands on the northern end of the Decumanus Maximus, exactly opposite the western terrace. The 15 m wide monumental public fountain was originally two-storey and decorated with sculptures.

In 1998 a marble block with an inscription was found in a wall a little further along the main street. It indicates that the nymphaeum with marble statues was donated by a certain Aurelios Diophantes, who held the position of Astynomos (high police officer, city supervisor, or law enforcement officer).

For a clear view of the area covered use the map view.