The Duathamper or Elvenflow is one of two major rivers running through Cormanthor (the other is the River Ashaba). It runs along the southeastern border of the forest. The river is generally deep (more than 30' in most places) and wide, although it does become narrow and shallow enough in places to wade across.
Despite the river being deep and wide in most places, it is possible to find spots across which one can wade. It is spanned by three black granite bridges, constructed by the elves.
Dozens of narrow shallow streams diverge from the river as it runs its course, although these are rarely found on maps, and they often end in small ponds.
Every spring, the heavy rains have a chance of causing the river to flood its banks, although the flooding is not severe, but it will cause hundreds of fish and frogs to become stranded in the muddy river banks