river capture

The diversion (capture) of the headwaters of one river into a neighbouring river. River capture occurs when a stream is carrying out rapid headward erosion (backwards erosion at its source). Eventually the stream will cut into the course of a neighbouring river, causing the headwaters of that river to be diverted, or ‘captured’.

The headwaters will then flow down to a lower level (often making a sharp bend, called an elbow of capture) over a steep slope, called a knickpoint. A waterfall will form here. Rejuvenation then occurs, causing rapid downwards erosion. An excellent example is the capture of the River Burn by the River Lyd, Devon, England.