When this water falls on the ground, some of it seeps into the soil and excess flows out as a stream or as run off. The topsoil however, can hold only a fraction of water that falls on it. The excess quanitity of water infiltrates into the ground by force of gravity, which is called seepage or percolation and builds groundwater table. The aquifier may be scientifically defined as a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells, borewells etc. These underground reservoirs of water residing in the pores or cracks of rocks are, what we draw out by digging wells and tube wells.
Ground water is a very valuable economic commodity.
The conservation of this precious ground water is very important because it moves through soil and many years may be required to replace hastily pumped water. Therefore, in areas where ground water is used extensively, care must be taken that no extra water is withdrawn in a year than the quantity replenished by natural process. To avoid depletion of ground water level, the aquifiers must be recharged in whichever way possible. The Solution lies in adopting better water management techniques, such as, harvesting of rain water, recharging the underground aquifiers, construction of underground Bandhara in rivers to recharge wells, borewells, borewells, ponds, etc., on the banks of the river. Artificial recharge may be defined as the process of augmenting the underground water Table by Artificial infiltration of rainwater and surface run off.