A meander is a landform caused by erosion and deposition. Meanders form in the middle and lower courses of a river. Meanders can be found in many rivers, such as the Mississippi River or the Amazon River. Meanders are “S-shaped bends”, found along the course of the river channel. Erosion occurs on the outside bend of a meander, while deposition occurs on the inside bend.

Meanders form where the slope of the land is lower and the river is wider and deeper. The river will be able to transport a larger load. Lateral erosion, in the form of hydraulic action and abrasion, will lead to the formation of meanders. Hydraulic action, the force of flowing water, will loosen and remove material from the channel sides. Abrasion, erosion caused by the river’s load, will erode the sides and bed of the river channel, wearing away rocks.

The river will adopt a winding course, known as sinous. The water current will adopt what is called a “helicoidal flow”, ensuring an ongoing, continuing process.