Groundwater recharge is any water added to the aquifer zone. Groundwater discharge is any process that removes water from an aquifer system. Natural springs and artificial wells are examples of discharge processes. Porosity, permeability, and specific yield are important properties. Grain shape and cementation affect porosity.
Permeability is the capability of a rock or sediment to allow the passage of fluids.
Permeability is dependent on the size of pore spaces and the degree to which the pore spaces are interconnected. Grain shape, grain packing, and cementation affect permeability. An aquifer must be sufficiently porous and permeable to store and conduct groundwater. Pumping water from a well causes a cone of depression to form in the water table at the well site. Overpumping can have two effects.