When a river is extending its channel upstream by headward erosion, it may come into contact with the headwaters of a less vigorous river. The headwaters from the minor river may be diverted into the more rapidly eroding channel. There is often a sudden change of stream direction at the point of capture; this is the elbow of capture. See Mather (2000) Geomorph. 34, 3 for two examples of river capture; see also Bishop (1995) PPG19.
Subjects: Earth Sciences and Geography.