Groundwater

Category: Water

All waters of the earth's crust beneath the surface of the Earth in rocks in gaseous, liquid and solid states, referred to as groundwater.

Groundwater are part of the hydrosphere - water shell of the globe. They occur as drilling wells to depths of several kilometers. According VI Vernandskogo, underground water may exist to a depth of 60 km due to the fact that water molecules even at a temperature of 2000o C dissociated only 2%

Rough calculations of fresh water in the bowels of the earth to a depth of 16 kilometers gives the value of 400 million cubic kilometers, ie about 1 / 3 of the World Ocean.

The accumulation of knowledge about groundwater, which began in ancient times, has accelerated with the advent of cities and irrigated agriculture. Art installations dug wells up to several tens of meters has been known for thousands of years 2000-3000 BC in Egypt, Central Asia, India and China. In the same period came and spa treatment.

In the first millennium BC appeared the first presentation of the properties and origin of natural waters, the conditions of their accumulation and the water cycle on Earth (in the works of Aristotle and Thales - in ancient Greece; Kara Titus Lucretius and Vitruvius - in ancient Rome, and others).

Study of groundwater contributed to the expansion of work related to water supply, construction kaptazhnyh structures (eg, qanats the peoples of the Caucasus, Wed Asia), extraction of salt water for evaporation of salt by digging wells, and then drilling (the territory of Russia, 12-17 century) . Later arose the concept of non-pressure water, pressure (rising from the bottom up) and flowing. The latter are called artesian - from the province of Artois (the ancient name of "Artesia") in France.