The abandoned meander creates a body of water known as an oxbow lake. Abandoned meanders can form during a flood or when the river cannot carry excess sediment through the bend, so the river finds a new path to flow. Over time, the ends of the curve formed by the meander become very close together and the meander is cut off and abandoned (abandoned or cutoff meander). Meanders change position by eroding sideways and slightly downstream. In addition, it depends on other variables such as the lithology of the river margins, the discharge, whether there is a floodplain or not, etc. Meanders move over time through simultaneous processes of erosion and sedimentation. The development of meanders increases the length of the river and thus decreases its slope. They form more easily in floodplains with a low gradient. How are meanders formed?Ī meander is formed when the water flow velocity diminishes in the river, thus forming curves or meanders. When they are above the water level, they can be recognised forming ridges. As sediments deposit in the inside of a meander, point bars become larger, composed of sediment that is well sorted. Point bars are crescent-shaped deposits of sand and gravel that accumulate on the inside of a river bend. A meander forms as a watercourse erodes the sediments of an outer, concave bank and deposits sediments on an inner, convex bank (point bar), leading to a meandering channel. Meanders are curves in the middle-lower course of a river.
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