A catchment is any device or structure that captures water. Impact of a drop of water Water is a chemical substance that is essential to all known forms of life[1]. It covers 71% of Earths surface. ...

General description

Catchment area or drainage basin is the term used to describe the area which is drained by a river. It is sometimes called the river basin or watershed (see below). The catchment is the most significant factor determining the amount or likelihood of flooding. A drainage basin is the area within the drainage basin divide (yellow outline), and drains the surface runoff and river discharge (blue lines) of a contiguous area. ... Río Peralonso - El Zulia (Norte de Santander), Colombia River Gambia flowing through Niokolokoba National Park Nevėžis River in Lithuania A river is a natural waterway usually formed by water derived from either precipitation or glacial meltwater, and flows from higher ground to lower ground. ... A flood (in Old English flod, a word common to Teutonic languages; compare German Flut, Dutch vloed from the same root as is seen in flow, float) is an overflow of water, an expanse of water submerging land, a deluge. ...

Catchment factors

Catchment factors are: topography, shape, size, soil type and land use (paved or roofed areas). Catchment topography and shape determine the time taken for rain to reach the river, Catchment size, soil type and development determine the amount of water to reach the river. It has been suggested that Geomorphometry be merged into this article or section. ... For the American hard rock band, see Soil (band). ... Land use is the pattern of construction and activity land is used for. ... A roof tiled in imitation of thatch at Croyde, north Devon, England Rooftops in Vietnam Snow on the roof The roof, the top covering of a building, is one of the universal structures found on all buildings. ... Rain is a source of precipitation which forms when separate drops of water fall to the Earths surface from clouds. ...

Topography

Topography determines the speed with which the runoff will reach a river, clearly rain that falls in steep mountainous areas will reach the river faster than flat or gently sloping areas. Lyskamm, 4 527 m, Pennine Alps A mountain is a landform that extends above the surrounding terrain in a limited area. ...

Shape

Shape will contribute to the speed with which the runoff reaches a river. A long thin catchment will take longer to drain than a circular catchment.

Size

Size will help determine the amount of water reaching the river, as the larger the catchment the greater the potential for flooding.

Soil type

Soil type will help determine how much water reaches the river. Certain soil types such as sandy soils are very free draining and rainfall on sandy soil is likely to be absorbed by the ground. However, soils containing clay can be almost impermeable and therefore rainfall on clay soils will run off and contribute to flood volumes. After prolonged rainfall even free draining soils can become saturated, meaning that any further rainfall will reach the river rather than being absorbed by the ground. Patterns in the sand Sand is a granular material made up of fine rock particles. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ... Look up Saturation in Wiktionary, the free dictionary. ...

Land use

Land use will contribute to the volume of water reaching the river, in a similar way to clay soils, only faster. Rainfall on roofs, pavements and roads will be collected by rivers with almost no absorption into the groundwater. Pavement may refer to: Pavement (material): An American English term referring to the durable surfacing of roads and walkways. ... This article or section does not cite its references or sources. ... Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of geologic formations. ...

Watershed

Another common term for catchment is watershed. This link leads to a website showing a flash animation of how rain falling on to the landscape will drain into a river depending on the terrain. A website (or Web site) is a collection of web pages, images, videos and other digital assets and hosted on a particular domain or subdomain on the World Wide Web. ... A Flash animation or Flash cartoon is an animated film which is created using Macromedia Flash animation software and often distributed in the . ...

See also

• Catchment area
• Drainage basin

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