To understand how a lot of water in the world, you need to start to imagine how may look the volume of water in one cubic kilometer. It is in this measured value of water reserves in the ground. Thus, the volume of all the water on our planet - 1500 000 000 km3. It is no coincidence, the Earth is called the blue planet from space it can see the blue ball with sushi spots. Freshwater resources account for about 10% of the total stock, and only a small portion of fresh water is surface water. The main supply of fresh water is in the earth's crust. There is concentrated about 190 million. Km3. Sometimes, underground water are at a distance of tens to hundreds of kilometers from the surface of the earth - the underground deep-lying water. This water is under considerable pressure in the ground. Rivers, lakes, and other sources of water that are in proximity to the surface, called the surface water. Such waters have a significant difference from the deep layers of water - the availability of such water is easy to produce, and often they are collected in different reservoirs and wells. However, these waters are less protected from contamination, as always in contact with the soil. Another body of fresh water, difficult in getting, but is a huge reserve for Earthlings (20-30 mln.km3) is concentrated in the glaciers of Antarctica, Greenland, the Arctic Ocean islands. Fresh water is also found in the drop-down of atmospheric precipitation - rain and snow. Also, people have learned to desalinate water, seas and oceans, but has practiced a little. Although in some eastern countries in the restrooms can be found sea water, but the use for such purposes is the exception rather than the natural development.
The main sources of fresh water have been and remain the rivers and lakes. The largest reservoir lake is considered to Lake Baikal, which contains 20 th. Km3 of water. The water of this lake is considered the purest lake water, it is very low percentage of dissolved and suspended mineral substances, virtually no organic matter, but a lot of oxygen. Baikal water is so pure that you can easily see the stones that lie even at a depth of 40 m.
Fresh water is divided into two types according to their chemical composition: the actual fresh and mineral water.
Fresh water is never found in nature is absolutely clear, as the universal solvent, always contains a certain percentage of minerals and dirt, so should be efficiently cleaned before eating. Tap water passes some cleaning before entering into our homes, but often this is not enough, so you should use household water filters.
Its healing qualities of mineral water acquired over a long period, enriched with healing minerals from specific breeds, near underground reservoirs of water. According to its pH indicator is acidic, alkaline or neutral. In the name of water incorporated as the basic structure, such as sodium chloride or chloride-sulphate.
Artesian springs - a deep-lying water sources. They are well protected from the effects of industrial, agricultural and bacterial contamination. To gain access to the artesian water use special drilling machines to fall well steel tubes, which are driven by powerful pumps artesian water withdrawn through the conduit to the surface. During the delivery of water to the surface it can penetrate contamination, such as water can often contain an unfavorable mineral composition to humans. Therefore, this water must be cleaned using industrial or household filters.
Spring Water - Water from springs and keys, who follow the way to the earth's surface from the Earth's interior. Such water may be fresh water or mineral. Often, in our latitudes, close to the major temples were built springs and spring ennobled to the people it was convenient to draw water. Now the springs can be closed as the water quality deteriorates significantly due to the surrounding soil contamination. In large cities with particularly dirty water, demand bottled spring water, which is taken from places far outside the city, factories and landfills. The quality of such water is regularly monitored by the sanitary services. However, the use of bottled water, certainly not so convenient, effective as tap water, purified water quality filters.
Well water is still widely used in rural areas, pit 10 meters can sometimes provide the village with water. The use of this water lies a great danger: through the soil into the well water contains all kinds of agricultural waste (pesticides, nitrites, nitrates, heavy metal).
On the domestic needs of man usually spends no more than 10% of all fresh water used, industry and agriculture uses the remaining 90%. For example, to get a kilo of sugar, a person spends about 200 liters. water for the production of a kilogram of synthetic rubber about 2400l. Every year, the world's costs are increasing, in living conditions people use equipment that consumes more water - such as washing machines are spending twice as much water per load than when a person washing dishes by hand. Industrial development also entails additional expenditure.
Before water from lakes, rivers and underground sources comes into use, it is processed, after the industrial or domestic use, water is also cleared to return to the rivers and lakes. Tap water usually has repeatedly been used before to get to our house.
Clearly, the most convenient way to obtain water remain rivers and lakes. People have always tried to build their cities near large rivers and lakes, and now urban water needs are served by surface water. Drilling deep wells, which would be able to supply large volumes of water, major cities can bring to an environmental disaster. Not enough, in some parts of the world aquatic freshwater sooner or later lead to treatment to the world's ocean water reserves and active practice of using desalination, industrial water treatment systems.