Coastal And Fluvial Geomorphology Codexery

Drainage basin

A land area where surface water converges to a single outlet.

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All surface water on a land area that drains to a common terminus, like a river's mouth or a lake, defines that region as a drainage basin.[1] Elevated terrain such as ridges and hills creates a drainage divide that marks the boundary between neighboring basins.[1] The term "watershed" in North America typically denotes a drainage basin, whereas in other English-speaking regions it more often refers solely to the dividing line.[2]

Key facts and history

A hierarchical arrangement emerges when smaller basins join together at river confluences to form a larger basin.[3] In an endorheic (closed) drainage basin, water collects in an interior sink, such as a permanent or dry lake, instead of reaching the ocean.[4] According to the U.S. Geological Survey, the majority of precipitation that lands in a drainage area accumulates in the stream and eventually passes a monitoring site.[5] A stream gauge positioned at a basin's outlet can quantify the water discharge from that basin.[6]

Tributaries formed by flowing water within a basin can alter the landscape's configuration.[7] Dendritic patterns, the most common drainage pattern, arise from rock that erodes readily.[7] Trellis and rectangular patterns constitute the two other primary drainage pattern types.[7] The quantity of water that ultimately reaches a river is influenced by soil type; for instance, sandy soils drain freely while clay soils are nearly impermeable.[8]

Even soils that normally drain freely can become waterlogged after extended rain, causing subsequent rainfall to flow into the river instead of soaking in.[8] Managing water resources by individual basin has become standard practice because drainage basins function as coherent hydrological units.[9]

What the cited sources add

The Virginia Department of Conservation and Recreation describes a true watershed as a region where all surface drainage converges to one point, which differs from hydrologic units that can have several outlets.[10] Earle's "Physical Geology" states that the height of land separating two drainage basins forms their boundary, and a water droplet landing exactly on that boundary could travel into either basin.[11] The same source indicates that trellis drainage patterns commonly form in areas where folded or tilted sedimentary rocks have undergone erosion.[11] WorldAtlas reports that the Atlantic Ocean possesses the largest drainage basin globally, covering roughly 26.9 million square miles.[12]

References

  1. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: "drainage basin", The Physical Environment (original not read by us) en.wikipedia.org
  2. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: Lambert, "The Field Guide to Geology", Checkmark Books, 1998, p. 130–13; Uereyen, "A Review of Earth Observation-Based Analyses for Major River Basins", Remote Sensing, 9 December 2019, p. 2951; Huneau, "Intrinsic vulnerability mapping for small mountainous karst aquifers, implementation of the new PaPRIKa method to Western Pyrenees (France)", Engineering Geology, 2013-07-18, p. 81–93; Lachassagne, "Natural mineral waters", Encyclopédie de l'environnement, 2019-02-07; Labat, "Rainfall–runoff relations for karstic springs. Part I: convolu en.wikipedia.org
  3. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: "What is a watershed and why should I care?", University of Delaware (original not read by us) en.wikipedia.org
  4. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: "Hydrologic Unit Geography", Virginia Department of Conservation & Recreation (we also read that source) en.wikipedia.org
  5. "Watersheds and Drainage Basins", U.S. Geological Survey, June 8, 2019. facts only, no text reused. usgs.gov
  6. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: "Watersheds and Drainage Basins", U.S. Geological Survey, June 8, 2019 (we also read that source) en.wikipedia.org
  7. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: Earle, "13.2 Drainage Basins", Physical Geology, 2015-09-01 (we also read that source) en.wikipedia.org
  8. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: Huneau, "Intrinsic vulnerability mapping for small mountainous karst aquifers, implementation of the new PaPRIKa method to Western Pyrenees (France)", Engineering Geology, 2013-07-18, p. 81–93 (original not read by us) en.wikipedia.org
  9. Wikipedia, "Drainage basin" (CC BY-SA 4.0), which cites: "Twin Cities Metropolitan Area (TCMA) Watersheds", Minnesota Pollution Control Agency, 2010-09-07 (original not read by us) en.wikipedia.org
  10. "Hydrologic Unit Geography", Virginia Department of Conservation & Recreation. facts only, no text reused. dcr.virginia.gov
  11. Earle, "13.2 Drainage Basins", Physical Geology, 2015-09-01. facts only, no text reused. opentextbc.ca
  12. "Largest Drainage Basins in the World", WorldAtlas, 17 May 2018. facts only, no text reused. worldatlas.com

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Drainage basin (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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