Question

What is a dam? How do they help in maintaining water levels?

Answer 1

A dam is a concrete structure built on a river. It has high walls and many openings for letting in and holding back water. It is helpful in maintaining the water level in the river. During heavy rainfall, when the water level rises in the rivers, the water enters the dam and gets stored in it. This helps in preventing floods. When conditions of a drought occur, i.e., when there is no rainfall in the region and the river level decreases, the gates of the dam are opened to let the stored water flow out.