Water storage is an important part of many societies, and there are several ways to store water. A RESERVOIR is a large body of water, usually created by damming a river or stream, and is used to store water for irrigation, drinking, and other uses. A TANK is a large container, usually made of metal or concrete, used to store water for drinking, irrigation, and other uses. A CISTERN is a large container, usually made of stone or concrete, used to store rainwater for drinking, irrigation, and other uses. Finally, a DAM is a barrier built across a river or stream to control the flow of water and is often used to create reservoirs.