<P> An oxbow lake is a U-shaped lake that forms when a wide meander from the main stem of a river is cut off, creating a free - standing body of water . This landform is so named for its distinctive curved shape, resembling the bow pin of an oxbow . In Australia, an oxbow lake is known as a billabong, from the indigenous Wiradjuri language . In south Texas, oxbows left by the Rio Grande are called resacas .' </P> <P> The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether or not it is cut off from the main stream . </P>

In which course of the river are oxbow lakes formed