when does a river develop meanders?

Answer 1

When it comes up against hard rock, it will then find the easiest way around it. In time it may erode the rock and form a new course and the meander will be cut off and become an oxbow lake.

Answer 2

A meander is a bend in a river, also known as an oxbow loop. A stream or river flowing through a wide valley or flat plain will tend to form a meandering stream course as it alternatively erodes and deposits sediments along its course. The result is a snaking pattern as the stream meanders back and forth across its floodplain. When a meander gets cut off from the main stream body, an oxbow lake is formed.

Rivers are constantly changing their course....

A meander is formed because the river flows faster on the outside edge of any small curve and slower along the inside edge. Deposition of sediment occurs on the inner edge because the river, moving slowly, cannot carry its sediment load, creating a slip-off slope. The faster moving current on the outside bend has more erosive ability and the meander tends to grow in the direction of the outside bend, forming a river cliff. This can be seen in areas where willows grow on the banks of rivers; on the inside of meanders, willows are often far from the bank, whilst on the outside of the bend, the roots of the willows are often exposed and undercut, eventually leading the trees to fall into the river. This demonstrates the river's movement.

Answer 3

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