Dams are solid barriers constructed across rivers to store flowing water for uses like drinking water, irrigation, hydropower, flood control and recreation. The main parts of a dam include the dam body, reservoir, spillway and water intake structures. Dams are classified based on their size, height and structural design. The most common types are gravity dams, arch dams, buttress dams and earth/embankment dams. While dams provide many benefits like irrigation, energy and flood control, they can also cause issues like flooding, disruption of ecosystems and communities, and high construction costs.