The rain water and the
water from melted ice that reaches under the surface of the earth through pores
and cracks are called underground water. Some underground water may originate
from the steam rising from molten rock materials deep within the earth. Erosive
action of water on limestone rocks turns their pores into such big sink holes
that even a river if that is drained into them would disappear. Fell Bank River in Yorkshire
sank into a 111- meter deep hole.
Springs and artesian wells owe their existence to the
flow of underground water. Artesian wells are of great economic importance in
the mountain ringed basins in the semi-arid climatic regions of the world.
There exist more than 18 thousand artesian wells in the world’s largest
artesian basin in Australian. Artesian wells have been sunk in the Terai region
of India
for irrigation and supply of drinking water. The underground water is very
useful in our daily lives. It not only provides us the drinking water but also
a valuable source of water for irrigation purposes.