Losing stream

The water infiltrates into the ground recharging the local groundwater, because the water table is below the bottom of the stream channel.

This is the opposite of a more common gaining stream (or effluent stream) which increases in water volume farther downstream as it gains water from the local aquifer.

[1] Losing streams are common in arid areas due to the climate which results in huge amounts of water evaporating from the river generally towards the mouth.

[2] Losing streams are also common in regions of karst topography where the streamwater may be completely captured by a cavern system, becoming a subterranean river.

There are many natural examples of subterranean rivers including:

The cave of source of the Buna can be entered by boat and dived through a cave system serving as an effluence of the Zalomka .
Map of the lost streams of Idaho