The volume of water held within aquifers.

• A. Groundwater storage
• B. Surface storage
• C. Stemflow
• D. Altitude

Answer: (A)

Groundwater storage is the total amount of water stored in aquifers underground. Aquifers are layers of permeable rock or sediment with interconnected pore spaces that hold and transmit water. The volume of water present in those pore spaces at any given time is groundwater storage, reflecting how much water the aquifer can store and release through processes like recharge from infiltration and withdrawal via pumping. This is different from surface storage, which is water held on the surface in lakes, ponds, and reservoirs; stemflow is water that runs down plant stems during rainfall; and altitude is simply elevation and doesn’t describe underground storage.