Oxbow lake facts for kids

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.

Images for kids

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  This picture of the Nowitna River in Alaska shows two oxbow lakes – a short one at the bottom of the picture and a longer, more curved one at the middle-right. The picture also shows that a third oxbow lake is probably in the making: the isthmus or bank in the centre of the most prominent meander is very narrow – much narrower than the width of the river; eventually, the two sections of river on either side of an isthmus like that tend to break through and create a new, straighter course; a new river bank then starts to accumulate, sealing off the meander and leaving another oxbow lake.

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  The swirls and curves of the previous courses of the Songhua River in northeast China can easily be seen in this satellite photo

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

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  A Horseshoe or oxbow lake near Hughes, Arkansas. 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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  The Oxbow, on the Connecticut River, Thomas Cole

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

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  The proposed oxbow lake of Saraswati Flumen from Cassini RADAR images.

See also

In Spanish: Brazo muerto para niños