What is Avulsion in Geography?
In geography, avulsion refers to a dramatic and sudden change in a river’s course. It’s essentially the abandonment of an existing channel and the formation of a completely new one, often over a short period of time. This can happen due to several factors, like:
Floods: Powerful floods can erode riverbanks, creating breaches and diverting waterflow into a new path. This is particularly common in rivers with loose sediment deposits like sand and silt.
Sedimentation: As rivers carry sediment downstream, they also deposit it along their channels. This buildup can raise the riverbed and decrease the channel’s slope, making it easier for water to find a steeper, shorter path elsewhere.
Accumulations of Debris: Large accumulations of logs or debris can obstruct a river’s flow, forcing water to carve its way around the blockage, creating a new channel.
Tectonic activity: In rare cases, earthquakes or other geological events can shift the landscape, causing rivers to change course abruptly.
Examples of avulsions include:
1. The Kosi River in India, known for its frequent and catastrophic avulsions that have caused major displacements and loss of life.
2. The Mississippi River, where avulsions have contributed to the development of its vast birdfoot delta.
