What is hydrology?

The Concise Oxford Dictionary (1990) defines hydrology as: “The science of properties of the earth's water, especially of its movement in relation to land.”

Hydrology is primarily concerned with the amounts and quality of water moving and accumulating on the land surface and in the soils and rocks near the surface. It therefore encompasses water in rivers, lakes, aquifers and glaciers. Hydrology embraces a wide range of interests including scientific and engineering applications. The diagram below, based on the BHS Research Strategy "Sustainability in a changing world: the key role of hydrology", illustrates the major components of hydrological science and its interactions with a broad range of disciplines.

Hydro-meteorology spans the interface between meteorology and hydrology, and professionals active in this subject may have trained in either or both disciplines. Hydro-geology addresses the science of water in the ground and has, as its name suggests, a close affinity with the geological sciences. Hydro-ecology is concerned with the aquatic habitats required for the survival of particular flora and fauna, and the changes that may occur in these conditions through human intervention.