The extraction of groundwater, pumped from underground aquifers, as a source of freshwater. In many aquifers the groundwater has to be pumped out through boreholes or wells. As water is abstracted the water table is lowered around the borehole. If rates of abstraction exceed rates of groundwater recharge within an aquifer, the water table can fall across a wide area. Borehole yields decline when this happens, and wells begin to dry up. Sometimes it is necessary to sink boreholes deeper into the aquifer, which further lowers the water table. Groundwater depletion follows, and water supplies are threatened if not reduced.
Subjects: Environmental Science.