Explaining The Universe on Instagram: "Follow (us) @ExplainingTheUniverse to learn something NEW every day 🧠💫 A dam is a barrier built across a river or stream to control the flow of water. By holding back water, dams create reservoirs that can be used for drinking water, irrigation, hydroelectric power generation, flood control, and recreation. There are several types—such as gravity dams (which rely on their weight to resist water pressure), arch dams (curved, transferring force into the val