Meanders are loop-like bends in the middle course of a river.

Meanders are a common feature of lowland rivers where the land becomes flat, and are named after the meander river in Turkey. They occur because the river is, at this stage, carrying a heavy sediment load. If an obstruction is encountered some of this sediment is deposited and the current is then diverted, curving away from this bank and eroding the opposing bank. In this way the flow is diverted from one bank to another and over time the curves (or "meanders") become gradually more pronounced. This continual, dynamic activity also means that the meanders move gradually downstream. In this way the curves may become so exaggerated that only a thin strip of land prevents the river from traveling a full circle. Both ends of the meander may now become clogged with sediment and eventually, the river may break through this strip of land, becoming temporarily straightened. The abandoned meander now becomes an ox-bow lake.

The distance between meanders in related to factors such as width but typically the average meander wavelength is 10-14 times channel width. Because this pattern is due to the natural characteristics of running water an aerial photograph of the meander pattern of a large river and that of small stream would be very similar. Meanders are important because they provide a range of environmental conditions including pools and riffles, eroding cliff habitat, sun and shade and exposed and sheltered sites. Straightening of meanders in addition to destroying much of this variation also shortens the watercourse. It may also cause the river to widen as its banks erode which leads to shallower water and less wildlife.

How are Meanders formed?