In human geography, a catchment area is the area from which a location, such as a city, service or institution, attracts a population that uses its services and economic opportunities. Catchment areas may be defined based on from where people are naturally drawn to a location (for example, labour catchment area) or as established by governments or organizations for the provision of services.
Governments and community service organizations often define catchment areas for planning purposes and public safety such as ensuring universal access to services like fire departments, police departments, ambulance bases and hospitals. In business, a catchment area is used to describe the influence from which a retail location draws its customers. Airport catchment areas can inform efforts to estimate route profitability.
Catchments can be defined relative to a location and based upon a number of factors, including distance, travel time, geographic boundaries or population within the catchment.
Catchment areas generally fall under two categories, those that occur organically, i.e., "de facto" catchment area, and a place people are naturally drawn to, such as a large shopping centre. Catchment areas in terms of a geographical location is a low lying region in which water from higher areas collect into a single water body. The sources of water collected can vary from rainwater to melted snow. Catchment areas may drain their water into other lower lying basins or into a single place, usually a lake, in the case of a closed catchment. A catchment area in terms of a place people are drawn to could be a city, service or institution.
Catchment area boundaries can be modeled using geographic information systems (GIS). There can be large variability in the services provided within different catchments in the same area depending upon how and when those catchments were established. They are usually contiguous but can overlap when they describe competing services.
GIS technology has allowed for the modeling of catchment areas, and in particular those relating to urban areas. Based on travel time between rural areas and cities of different sizes, the urban–rural catchment areas (URCAs) is a global GIS dataset that allows for comparison across countries, such as the distribution of population along the rural–urban continuum. Functional economic areas (FEAs), also called larger urban zone or functional urban areas, are catchment areas of commuters or commuting zones.
When combined with hospital data, catchment areas can define the epidemiological disease burdens or forecast hospital needs amid a disease outbreak.
Catchment areas may be established for the provision of services. For example, a school catchment area is the geographic area from which students are eligible to attend a local school. When a facility’s capacity can only service a specific volume, the catchment may be used to limit a population’s ability to access services outside that area. In the case of a school catchment area, children may be unable to enroll in a school outside their catchment to prevent the school's services being exceeded.