Скачать или смотреть JAM Achiever series - Hydrogeology Part – 2, Tamil

blog link: https://sggeology.blogspot.com/2024/0...

Vertical distribution of Ground water


Zone of aeration
Consists of interstices occupied partially by water and partially by air. Sub divided into the soil water zone, the intermediate vadose zone, and the capillary zone

Zone of saturation
All interstices are filled with water under hydrostatic pressure. The saturated zone extends from the upper surface of saturation down to underlying impermeable rock. phreatic surface - is defined as the surface of atmospheric pressure and appears as the level at which water stands in a well penetrating the aquifer.

Saturation extends slightly above the water table due to capillary attraction; however, water is held there at less than atmospheric pressure. Water occurring in the zone of saturation is in commonly referred to simply as groundwater, but the term phreatic water is also employed.

Types of Aquifers


Aquifers may be classed as unconfined or confined depending on the presence or absence of a water table.

An unconfined aquifer is one in which a water table varies in undulating form and in slope depending on areas of recharge and discharge, pumpage from wells, and permeability.
Perched water table occurs wherever a groundwater body is separated from the main ground water by a relatively impermeable stratum of small areal extent and by the zone of aeration above the main body of groundwater.
Confined aquifers, also known as artesian or pressure aquifers, occur where groundwater confined under pressure greater than atmospheric by overlying relatively impermeable stata