When running through low flatland plains, rivers begin to meander. Meandering is caused by slow flow speeds, in which the erosive force of the river wears down its outer curves more than its inner curves. This results in side erosion. Over time, loose material can pile up on the river's inside curves, forming sandbanks.

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Sometimes, a river can wear down its outer curve so vigorously that its embankment erodes away completely. As a result, the river will cut through the curve, creating a new, straight channel through the terrain. When this happens, curves of the former river can be separated from the new, straighter river, forming an oxbow lake.​