All water present under the surface of soil is called ground water this water may be present in the soil pores or in open spacing.
Important Facts of Ground Water
volume of ground water present in upper 800 meter or the ,8 km of the is nearly 20 percent of the volume of all water which exists on the earth surface i.e sea ,rivers, stream etc.
Chief Source of Ground Water
Basically the big, main, important source of ground water is downward percolation of the rain water. we can say it meteoric water when precipation is occur the water some on soil and the when water reaches on the surface of the earth , earth suck some some water which the major source of the ground water.
Occurrence of Ground Water
Ground water mostly occurr in three zones
1) Zone of Aeration
a) Zone of aeration extends from ground surface down up to the capillary fringe
b) Under saturated zone, voids are partly filled with the water as well as air
c) Infiltrated rainwater passes through this zone to reach water
d) A certain amount of water is always held in the pores due to the molecular attraction and all the water in this zone is called vadose water
2) Zone of capillary fringe
a) This zone lies between the zone of aeration and zone of the saturation. water in this zone is conecrd with both aeration and saturation zone
b) In course grained soils the capillary water rises only a few centimeters above the unit , but in cause of the fine grain soils or clay etc it may rise from 10 to 15 meters.
3) Zone of saturation
extendo from water table down woards voids are complety filled with water and there are no void spaces for the air bascially formally the water exists in that zone is called ground water.
how to obtain ground water(sources)
the main sources to obtain ground water are wells, spring etc
wells are the vertical structures or we can say openings or shafts excavated into the zone of saturation.
when the ground water flows out at the ground surface it is called the spring. springs are formed at places where water table intersect the ground surface level or simply the formation of the water table occurs where the water table is higher.
that,s all the knowledge i have thanks for reading.