An underground water reservoir is called what?

• A. A large surface water body
• B. An underground water reservoir
• C. The process of water evaporation
• D. Water vapor in the atmosphere

Answer: (B)

Groundwater is stored underground in permeable rocks and soils, forming a natural reservoir that can supply wells. The term for this underground water reservoir is an aquifer. An aquifer is a layer of rock or sediment that holds and can transmit groundwater, sometimes overlain by less permeable layers that confine it. So, for the question about an underground water reservoir, the correct term is aquifer. The other options describe surface water, the process of turning liquid water into vapor, or water vapor in the air, none of which refer to an underground storage system.