ABSTRACT
Aquifer storage describes the volume of water released from or added to a unit area of aquifer resulting from a unit change in hydraulic head. The source of water released from storage in confined aquifers is matrix compression and water expansion with the storage coefficient ranging from 0.005 to 0.00005. The source of water released from unconfined aquifers is largely due to dewatering of the pore space and is called specific yield with values ranging from 0.01 to 0.30. The volume of water released from confining units and horizontal strain can yield significant quantities of water to aquifers during long-term pumping events.
