GEOLOGY

Detailed explanation-1: -artesian well, well from which water flows under natural pressure without pumping. It is dug or drilled wherever a gently dipping, permeable rock layer (such as sandstone) receives water along its outcrop at a level higher than the level of the surface of the ground at the well site.

Detailed explanation-2: -Aquifers that are bounded on the top and bottom by aquitards are called confined aquifers. In confined aquifers the groundwater is under pressure. If penetrated by a well, the water level in a confined aquifer will rise above the top of the aquifer.

Detailed explanation-3: -If such a confined aquifer is tapped by a well, water will rise above the top of the aquifer and may even flow from the well onto the land surface. Water confined in this way is said to be under artesian pressure, and the aquifer is called an artesian aquifer.

Detailed explanation-4: -A confined aquifer is one which is sandwiched between two aquitards. A confined aquifer is only very slowly recharged because of the impermeable upper confining layer.