Hydrology

(the science of water which denotes the study of the properties, distribution, and movements of water on land surfaces, in the soil, and through the subsurface rocks of the earth)

hydrologic (adjective) (not comparable)
Referring to the use of water: The hydrologic distribution of water includes its conservation on Earth and in its atmosphere, particularly to the surface of the land.
hydrologist
1. A scientist or technician who specializes in hydrology or the science of water in various formats and applications.
2. A practitioner of hydrology who works within the fields of either earth or environmental science, or civil and environmental engineering.
hydrology
The scientific study of the portion of the earth that is water, in liquid, frozen, or vapor form; as it moves or is distributed on the earth's surface, under the ground, or in the atmosphere.