A concrete dam is a large structure built across a river or a waterway to hold back water. Made primarily of concrete, these dams are designed to create reservoirs for water storage, hydroelectric power generation, and flood control. The solid construction allows them to withstand the immense pressure of the water they contain. Concrete dams can vary in design, with the most common types being gravity dams and arch dams. Gravity dams rely on their weight to resist water pressure, while arch dams use a curved shape to direct the force of the water into the canyon walls. Both types play a crucial role in managing water resources and supporting local ecosystems.