Hydrology studies the principles of water movements over the Earth. The main aim of the hydrological research is to define an occurrence of water, its circulation, spatial distribution, physical and chemical properties, and it relation to biosphere. As the water is present in all spheres of natural environment, hydrology is closely interrelated with meteorology, climatology, pedology, geology, and ecology. Water abundance, shortage, and pollution represent limiting factors for human development in various regions all over the world. Hence, the hydrological forecasting (both floods and drought) and water quality monitoring are of high importance for the human society.