Catchment area (human geography)
In human geography, a catchment area is the area and population from which a city or individual service attracts visitors or customers. For example, a school catchment area is the geographic area from which students are eligible to attend a local school. Another application of the concept is that airports can be built and maintained in locations where they would be best utilized by the surrounding population with minimal driving distance. Local governments and community service organizations often define catchment areas or service areas for public safety (e.g., fire and police) and emergency medical services.
Catchment areas are generally founded either on formal local government boundaries or else on some other geographic basis. For example, a neighborhood or district of a city often has several small convenience shops, each with a catchment area of several streets. Supermarkets, on the other hand, have a much lower density, with catchment areas of several neighborhoods (or several villages in rural areas). This principle, similar to the central place theory, makes catchment areas an important area of study for geographers, economists, and urban planners.
Catchment area (hydrology)
A catchment area (also known as drainage basin or watershed) is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point at a lower elevation, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean. For example, a tributary stream of a brook which joins a small river, which is tributary of a larger river is thus part of a series of successively smaller area but higher elevation drainage basins (watersheds)