Keo

As a river flows across relatively flat terrain, it often develops sinuous bends called meanders. Over time, due to erosion on the outer banks and deposition on the inner banks of these bends, the meanders become more pronounced. Eventually, the neck of a particularly pronounced meander may become so narrow that the river cuts through it, particularly during high flow events, creating a new, straighter channel. As a result, the old meander is cut off from the main flow of the river, leaving a crescent-shaped body of water known as an oxbow lake.