Rhimdath.
Rushdown.
Rhibdath.
The river Rhimdath flowed from its two wells 25 Miles apart in Hithaeglir between Langwell and the Old Ford to Anduin. As the name indicates both the exiled Noldorin name and the translation into human tungue shows it was a fast torrent river. It is not shown on the general map provided with Lord of the Rings but on the Wilderland map in the Hobbit even it is not named here. But the name is revealed in the Etymologies.