reservoir definitions
The Junghua Dam and reservoir on the Dahan Creek in Taoyuan City, Taiwan. A reservoir (etymology: from French rÃ©servoir a storehouse ) is a storage space for fluids. These fluids may be water, hydrocarbons or gas. A reservoir usually means an enlarged natural or artificial lake, storage pond or impoundment created using a dam or lock to store water. Reservoirs can be created by controlling a stream that drains an existing body of water.