Drainage basin
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide,[1] made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.[2]
Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water basin,[3][4] and impluvium.[5][6][7] In North America, they are commonly called a watershed, though in other English-speaking places, "watershed" is used only in its original sense, that of a drainage divide.
A drainage basin's boundaries are determined by watershed delineation, a common task in environmental engineering and science.
In a closed drainage basin, or
Drainage basins are similar but not identical to hydrologic unit code, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks. In a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins.[8]
Major drainage basins of the world
Ocean basins
About 48.71% of the world's land drains to the
The two major
The
Just over 13% of the land in the world drains to the
The Indian Ocean's drainage basin also comprises about 13% of Earth's land. It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, the Indian subcontinent, Burma, and most parts of Australia.[10]
Largest river basins
The five largest river basins (by area), from largest to smallest, are those of the
Endorheic drainage basins
The largest endorheic basins are in Central
In endorheic
Importance
Geopolitical boundaries
Drainage basins have been historically important for determining territorial boundaries, particularly in regions where trade by water has been important. For example, the English crown gave the Hudson's Bay Company a monopoly on the fur trade in the entire Hudson Bay basin, an area called Rupert's Land. Bioregional political organization today includes agreements of states (e.g., international treaties and, within the US, interstate compacts) or other political entities in a particular drainage basin to manage the body or bodies of water into which it drains. Examples of such interstate compacts are the Great Lakes Commission and the Tahoe Regional Planning Agency.
Hydrology
In
The majority of water that discharges from the basin outlet originated as
As water flows through the basin, it can form tributaries that change the structure of the land. There are three different main types, which are affected by the rocks and ground underneath. Rock that is quick to erode forms dendritic patterns, and these are seen most often. The two other types of patterns that form are trellis patterns and rectangular patterns.[14]
Rain gauge data is used to measure total precipitation over a drainage basin, and there are different ways to interpret that data. If the gauges are many and evenly distributed over an area of uniform precipitation, using the
Geomorphology
Drainage basins are the principal hydrologic unit considered in
Ecology
Drainage basins are important in
Modern use of
Resource management
Because drainage basins are coherent entities in a hydrological sense, it has become common to manage water resources on the basis of individual basins. In the
When a river basin crosses at least one political border, either a border within a nation or an international boundary, it is identified as a
Management of shared drainage basins is also seen as a way to build lasting peaceful relationships among countries.[20]
Catchment factors
The catchment is the most significant factor determining the amount or likelihood of
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, while catchment size, soil type, and development determine the amount of water to reach the river.
Topography
Generally, topography plays a big part in how fast runoff will reach a river. Rain that falls in steep mountainous areas will reach the primary river in the drainage basin faster than flat or lightly sloping areas (e.g., > 1% gradient).
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. It is also determined on the basis of length and width of the drainage basin.
Soil type
Soil type will help determine how much water reaches the river. The runoff from the drainage area is dependent on the soil type. 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. If the surface is impermeable the precipitation will create surface run-off which will lead to higher risk of flooding; if the ground is permeable, the precipitation will infiltrate the soil.[5]
Land use
Land use can contribute to the volume of water reaching the river, in a similar way to clay soils. For example, rainfall on roofs, pavements, and roads will be collected by rivers with almost no absorption into the groundwater. A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean.
See also
- Continental Divide of the Americas – Principal hydrological divide of North and South America
- Integrated catchment management – Environmental planning
- Interbasin transfer – transfer of water from one river basin to another
- International Journal of River Basin Management (JRBM)
- International Network of Basin Organizations
- Main stem – Final large channel of a riverine system
- River basin management plans – Water resources management
- River bifurcation – The forking of a river into its distributaries
- Tenaja – type of water basin or retention area, implying a natural or geologic cistern in rock which retains water; often created by erosional processes within intermittent streams
- Time of concentration
- Catchment hydrology
References
- ^ "drainage basin". The Physical Environment. University of Wisconsin–Stevens Point. Archived from the original on March 21, 2004.
- ^ "What is a watershed and why should I care?". University of Delaware. Archived from the original on 2012-01-21. Retrieved 2008-02-11.
- ISBN 0-8160-3823-6.
- .
- ^ .
Efficient management is strongly correlated to the proper protection perimeter definition around springs and proactive regulation of land uses over the spring's catchment area ("impluvium").
- ^ Lachassagne, Patrick (2019-02-07). "Natural mineral waters". Encyclopédie de l'environnement. Retrieved 2019-06-10.
In order to preserve the long-term stability and purity of natural mineral water, bottlers have put in place "protection policies" for the impluviums (or catchment areas) of their sources. The catchment area is the territory on which the part of precipitated rainwater and/or snowmelt that infiltrates the subsoil feeds the mineral aquifer and thus contributes to the renewal of the resource. In other words, a precipitated drop on the impluvium territory may join the mineral aquifer; ...
- .
The non-karstic impluvium comprises all elements of the ground surface and soils that are poorly permeable, on a part of which water is running while also infiltrating on another minor part. This superficial impluvium, if it exists, constitutes the first level of organization of the drainage system of the karstic basin.
- ^ a b "Hydrologic Unit Geography". Virginia Department of Conservation & Recreation. Archived from the original on 14 December 2012. Retrieved 21 November 2010.
- ^ S2CID 129463497. Archived from the originalon 2021-08-15. Retrieved 2021-08-15.
- ^ "Largest Drainage Basins in the World". WorldAtlas. 17 May 2018.
- GangaPublished by Microsoft in computers.
- ^ "drainage basin Definition, Example, & Facts". Encyclopedia Britannica. Retrieved 2021-10-22.
- ^ "Watersheds and Drainage Basins". www.usgs.gov. Retrieved 2021-10-22.
- ^ Earle, Steven (2015-09-01). "13.2 Drainage Basins".
- .
- ISBN 978-0-07-064855-5.
- ^ "EN 0705 isochrone map". UNESCO. Archived from the original on November 22, 2012. Retrieved March 21, 2012.
- ^ "Isochron Map". Archived from the original on 2021-09-03. Retrieved 2021-09-03.
- ^ "Twin Cities Metropolitan Area (TCMA) Watersheds". Minnesota Pollution Control Agency. 2010-09-07. Retrieved 2021-09-22.
- ^ bin Talal, Hassan; Waslekar, Sundeep (25 November 2013). "Water Cooperation for a Secure World". www.strategicforesight.com.