In the earth there is a huge amount of water, it is much more, than in all rivers and lakes of the world. Such waters which are in emptiness in the top part of earth crust are called underground. The underground waters lying on waterproof layer of rocks, the first from the earth's surface, are called ground. And the waters concluded between two such waterproof layers — interbedded.
Instruction
1. Waterproof breeds (sandstone, clay, granite) practically do not pass water. Water, having filtered, lingers on these breeds, fills cracks and intervals between them, collects and eventually forms a water-bearing layer. Unlike ground waters which are replenished with an atmospheric precipitation the thawing of snow filtering from all surface, interreservoir waters are in more difficult situation. Rain and melt water can get between two waterproof layers only on those sites where this waterproof layer is absent. The second way of formation of absolutely small amount of interreservoir waters - from water vapor from the melted magma. Therefore if ground waters are replenished every year and their quantity practically does not change, then interreservoir waters are replenished extremely slowly, their accumulation happens for hundreds and even thousands of years.
2. Sometimes interreservoir waters form sources, but in most cases get them from the drilled wells. When the water-bearing layer between impermeable rocks is completely filled with water, it is under pressure there. If to drill the well in this layer, then water under a pressure rises and gushes forth. The second name of such pressure head waters - artesian. Deep-well waters are located at a depth from 100 meters to several dozen kilometers. The well dug by means of this technology is called an artesian well.
3. For the person underground waters - the true wealth. Filtering into depth, they pass through a number of natural filters and, thus, are perfectly purified. Underground water is considered the best drinking water. The waters from the depths of the earth containing the increased amount of salts and gases are called mineral. They are used in the medical purposes - build sanatoria at sources. Thermal underground waters use for heating of houses, greenhouses, for receiving the electric power. Besides, underground waters are the important power supply of lakes and rivers, they provide plants with nutrients and moisture.