"Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil and environmental engineering.Hydrology is subdivided into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology."@en . . . .