V.G.Krivenko 

In the ХХI century, freshwater as a base of life on the Earth in all forms and, primarily, for human becomes the most important natural resource. Besides its direct use and sanitary-hygienic purposes, water is a basis of irrigated agriculture, industries and a source of biological resources and biodiversity. An increasing deficit of water resources significantly changes the economic and geopolitical interests of different countries in the world.