List of unusual drainage systems

The following is a list of unusual drainage systems.

Systems that cross a continental divide

Bahr Yussef is a canal which connects the Nile River to Fayyum endorheic basin in Egypt.
Traverse Gap, an ancient river valley now crossed by a continental divide; in historic times it was possible to ascend a watercourse from one side and descend the watercourse on the other.
The Danube Sinkhole near Möhringen, where the waters of the upper Danube river, which flows into the Black Sea, can sink into the Danube riverbed, through a system of caverns, that outflow towards the Radolfzeller Aach, a creek that flows into Rhine River, which flows into the North Sea.

The Kootenay River in British Columbia, a tributary of the Columbia River, passes a mere two kilometers from the source of the Columbia River, Columbia Lake.
The Tonlé Sap River in Cambodia flows north in the wet season and south in the dry season.
Lake Torrens in Australia, a normally endorheic lake that drains into the Spencer Gulf (Indian Ocean) via the Pirie–Torrens corridor after sufficiently extreme rainfall events.
Lake Vostok is a subglacial lake beneath the Antarctic ice cap.
The Au Sable River and Manistee River in Michigan, which drain into Lake Huron and Lake Michigan respectively, pass within 3 miles of each other in Crawford County.
The Inland Waterway of Michigan, a chain of rivers and lakes flowing into Lake Huron come within half a mile of Lake Michigan.
Semuc Champey – in Guatemala. The Cahabón River flows under a natural bridge supporting limestone-rimmed pools.
Unaweep Canyon, in the US state of Colorado, is unique because two creeks, East Creek and West Creek, flow out of opposite ends of the canyon, separated by the almost imperceptible Unaweep Divide.
Reversing Falls