Oxbow lake

Oxbow lake in Slovakia

An oxbow lake is a lake, or area of water, in a U-shape. It is made by special bends in a river, called meanders, getting farther away from the river until they become separate. The river becomes straight and the bend becomes a lake. This happens due to floods or when a meander's neck gets too thin.

Why does this happen?

Water flows at different speeds at different parts of the river. In the middle, farthest away from the sides (or banks), the water flows fastest. At the banks, the water flows slowest. When the river bends, water flows faster on the outside of the bend than the inside. The fast water on the outside 'erodes' the outside of the bend. This means it breaks bits of the bank off. At the same time, the slow water on the inside of the bend leaves behind mud, sand and parts of plants (deposition). Together, these make the bend move in the direction of the outside of the bend.

The bend moves farther and farther along until it leaves the river. The river becomes straight and the bend is left as an oxbow lake.

Oxbow Lake Media

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  A meander develops into an oxbow lake

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  A Horseshoe or oxbow lake near Hughes, Arkansas, on the border between Arkansas and Mississippi. The bulges in the border reflect changes in the course of the river; when the river shifted its course and cut off the former channel, the border remained unchanged.

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  Oxbow lakes on New Zealand's Taieri River have been converted into water meadows.

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  The Oxbow, on the Connecticut River, Thomas Cole

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  The swirls and curves of the previous courses of the Songhua River in northeast China

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  Early stages of formation of coastal plain oxbow lake in the Gower Peninsula of southwest Wales

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  The proposed oxbow lake on Saturn's moon Titan, from Cassini RADAR images