The largest momentary use of water is electrical power production where water is mainly used for cooling and condensation of steam being generated by the power station`s turbines. During this process water is heated on average of 7°C following which it is dumped directly into rivers and lakes creating additional heating - so-called «water`s thermal pollution». Science knows many natural water contaminants which are harmful to the health of a population, lead to mortality of fish, water birds, other creatures, and also destroy aquatic plants living in the water. Besides, not only poisonous chemical and oil pollutants but also an excessive amount of organic and mineral matter, washed out from the fields, are harmful to the aquatic ecosystems. The issue of water quality control is the most pressing issue these days.