Formation of an Oxbow Lake

Quck answer

An oxbow lake forms when a meandering river cuts off a meander bend, creating a U-shaped lake. It starts with a meandering river that erodes the outside bend of a meander, creating a neck of land called a “neck cutoff.” Over time, the river erodes through this neck cutoff, causing the river to take a new straighter path. The old meander bend becomes isolated and eventually fills with water, forming an oxbow lake. Oxbow lakes are common in flat floodplain areas and are important habitats for wildlife. They also provide insights into the history and evolution of rivers.


Do you enjoy spending a peaceful day at the lake? Some individuals like to take a fishing rod and spend their day trying to catch dinner in a small local lake. Others may prefer taking a scenic hike around a picturesque lake, such as Crater Lake.

If you reside near the Great Lakes, there are various activities you can engage in, ranging from water skiing to swimming. Lakes of different shapes and sizes offer recreational opportunities throughout the year.

If you live close to a river, you may have a specific type of lake in your vicinity. If you refer to a map and notice a lake with a crescent shape located near a river, it is likely an oxbow lake.

Oxbow lakes, also referred to as horseshoe lakes, loop lakes, or cutoff lakes, derive their name from their resemblance to the U-shaped collar placed around an ox’s neck for plowing. Their distinct shape is a result of the way they are formed.

An oxbow lake originates from a curve, known as a meander, in a river. As water flows around the curve, it moves faster on the outer side and slower on the inner side of the curve.

This has two effects. The water on the outer side of the curve erodes the river bank through a process called erosion. Conversely, the water on the inner side of the curve moves at a slower pace and deposits dirt, sand, silt, and other sediments, known as deposition.

Over time, these processes create a curve with a distinct U or crescent shape. As erosion and deposition continue, the land at the narrow ends of the curve, closest to the straight path of the river, diminishes in size.

Eventually, the river carves a new, straight path through that small piece of land, creating a shortcut that straightens the course of the river and leaves behind an oxbow lake. When observing an aerial photograph of an oxbow lake, it is often evident that it used to be a simple bend in the river.

Isolated from the main river channel, oxbow lakes do not have any inflow or outflow of water. Without sufficient rainfall, they may completely dry up. Many oxbow lakes that receive some rain transform into swamps, serving as thriving habitats for wildlife.

Give It a Try

Are you prepared for a swim? Engage in the following activities with a friend or family member:

  • If you live near a lake or river, ask an adult friend or family member to take you to visit the body of water. You can go fishing or swim if the weather permits. Take some time to observe the area and see what types of creatures depend on the water.
  • Watch an online animation that explains how oxbow lakes are formed. Are there any oxbow lakes near your location? Use online maps to look at the rivers in your area. Can you spot any oxbow lakes along the course of the river?
  • If you haven’t seen an oxbow lake before, you can view photographs of oxbow lakes online. It’s fascinating how the force of water can shape the land in such a way. In what other ways do we rely on the power of water?

Sources of Wonder

  • https://www.nationalgeographic.org/encyclopedia/oxbow-lake/ (accessed on January 16, 2019)
  • http://www.mbgnet.net/fresh/lakes/oxbow.htm (accessed on January 16, 2019)

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