How can altering a river channel prevent flooding?

Altering a river channel can prevent flooding by modifying its shape, width, or flow path to enhance water capacity and reduce overflow during heavy rainfall. Techniques such as widening the channel, deepening it, or creating floodplains can allow for greater water storage and improved drainage. Additionally, engineering structures like levees and flood walls can help redirect excess water away from vulnerable areas. These alterations aim to manage the river's flow more effectively, thereby minimizing the risk of flooding in adjacent regions.