A spring is a point of exit at which groundwater from an aquifer flows out on top of earth's crust (pedosphere) and becomes surface water. it is a component of the hydrosphere. springs have long been important for humans as a source of fresh water, especially in arid regions which have relatively little annual rainfall. springs are driven out onto the surface by various natural forces, such as gravity and hydrostatic pressure. they vary in volumetric flow rate from nearly zero to more than 14,000 litres per second (490 cu ft/s) for the biggest springs.

Source: Wikipedia