![]() It can also be called a horseshoe lake, a loop lake, or a cutoff lake. They are typically found in the middle and lower course of a river. An oxbow lake gets its name from the U-shaped collar placed around an ox's neck to which a plow is attached. Meanders and Oxbow Lakes A meander is a winding curve or bend in a river. These lakes eventually dried up to create acres of land for farming, housing, and industry. The Mississippi River is shorter now than it was in the 19th century, for instance, because engineers have cut off hundreds of meanders. On these plains, rivers often have wide meanders. Oxbow lakes usually form in flat, low-lying plains close to where the river empties into another body of water. The meander becomes an oxbow lake along the side of the river. Giant river otters ( Pteronura brasiliensis) frequently live in the Amazons oxbow lakes, and feed on about five kilograms (11 pounds) of fish per day. A lake forms as the river finds a different, shorter, course. Along the Amazon River in South America, oxbow lakes are common and their still waters provide a unique habitat for plants and wildlife. Oxbow lakes can be rich wildlife habitats. Oxbow lakes often become swamps or bogs, and they often dry up as their water evaporates. There is no stream or spring feeding the lake, and it doesn't have a natural outlet. This means that water does not flow into or out of them. Oxbow lakes are the remains of the bend in the river. Erosion and deposition eventually cause a new channel to be cut through the small piece of land at the narrow end of the meander. Silt and sediment build up on convex banks. The banks opposite the concave banks are called convex banks. The force of the rivers flowing water wears away the land on the meanders concave banks. The corners of the curves closest to each other are called concave banks. Meanders that form oxbow lakes have two sets of curves: one curving away from the straight path of the river and one curving back. This video illustrates and explains the step-by-step formation of meanders and oxbow lakes, two river landscapes located in the middle to lower course. ![]() ![]() A lake forms as the river finds a different, shorter, course. Eventually, the deposits from the flooding river may form a levee tall enough to keep the river from overflowing in that area.An oxbow lake starts out as a curve, or meander, in a river. Over time, the flooding river replenishes a significant amount of sediment into its valley, building up the sediment. Every time a river floods, it deposits the sediment it was carrying outside its boundaries. As water slows down it can no longer keep sediment grains in transport, and it deposits them. When a river floods, the area the water is flowing through increases exponentially. As the water breaches its bank, it escapes into the rest of the valley. The water is unable to maintain the speed it was going before, and it slows down. The river flow is diverted by an obstruction allowing the river. This lateral erosion caused by snaking meanders creates a flat valley over time. Meanders generally form under conditions of a gentle slope and sufficient water in rivers. Grain sizes of floodplain deposits vary from clay to gravel.Īs rivers meander through a relatively flat area, they erode sediment at the outer edge of any curves. \)įloodplains are large expanses of alluvium deposited by the decrease in river flow speed when rivers flood.
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