One of several variant names for a small river that ran down as two streams from the eastern foothills of the Misty Mountains, joining to form a single river that flowed on into Anduin in its northern Vales. This river is also known by the Elvish names Rhimdath and Rhibdad, all apparently equivalent to its Mannish name, 'Rushdown', and referring to the fact that it rushed down from the Misty Mountains into the Vale of the Great River.