An Oxbow lake forms when a river creates a meander, due to the river's eroding the bank. After a long period of time, the meander becomes very curved, and eventually the neck of the meander becomes narrower and the rivers cuts through the neck during a flood cutting of the meander and forming an oxbow lake. Meander-A Meander is one of a series of regular sinuous curves, bends, loops, turns or windings in the channel of a river stream.