How can dams prevent floods?

Dams can be used to prevent floods in several ways. The main way a dam helps reduce flooding is by controlling the amount of water that enters a river. When the dam is closed, the river flow is reduced and the reservoir behind the dam stores excess water.

This can help to reduce downstream flooding by preventing larger amounts of water from entering the river during heavy rainfall events. Additionally, dams can also be used to manage reservoir levels in order to lower the risk of flooding during periods of wet weather. By controlling the level of the reservoir, the dam can let more water out when there is a large amount of rain and store excess water when there is less.