Drainage basin. The dashed line is the main water divide of the hydrographic basin

A drainage basin is an extent of land where water from rain or snow melt drains downhill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea or ocean. A LAND attack is a DoS (Denial of Service attack that consists of sending a special poison spoofed packet to a computer causing it to lock up Water is a common Chemical substance that is essential for the survival of all known forms of Life. Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to In Hydrology, snowmelt is Surface runoff produced from melting Snow. "Riverine" redirects here For the use of that term in Maritime geography, see there A lake (from Latin lacus) is a Terrain feature (or Physical feature) a body of Liquid on the surface of a world that is localized to the A reservoir is most broadly a place or hollow vessel where Fluid is kept in Reserve, for later use An estuary is a semi-enclosed Coastal body of Water with one or more Rivers or Streams flowing into it and with a free connection to the open A wetland is an area of Land consisting of Soil that is Saturated with Moisture, such as a Swamp, Marsh, or Bog This article is about the body of water For other uses see SEA and Seas. An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. The drainage basin includes both the streams and rivers that convey the water as well as the land surfaces from which water drains into those channels, separated from adjacent basins by a drainage divide,water Shed or Water table . A drainage divide, water divide, divide or (outside North America) watershed is the line separating neighbouring Drainage basins ^[1]

The drainage basin acts like a funnel - collecting all the water within the area covered by the basin and channeling it into a waterway. A funnel is a pipe with a wide often conical mouth and a narrow stem Each drainage basin is separated topographically from adjacent basins by a ridge, hill or mountain, which is known as a water divide. A ridge is a geological feature that features a continuous elevational crest for some distance A mountain is a Landform that extends above the surrounding Terrain in a limited area with a peak A drainage divide, water divide, divide or (outside North America) watershed is the line separating neighbouring Drainage basins Other terms that can be used to describe the same concept are catchment, catchment area, catchment basin, drainage area, river basin and water basin. A catchment is any device or structure that captures Water. ^[2]

In the technical sense, a watershed refers to a divide that separates one drainage area from another drainage area. ^[3] However, in the United States and Canada, the term is often used to mean a drainage basin or catchment area itself. The United States of America —commonly referred to as the Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Watersheds drain into other watersheds in a hierarchical form, larger ones breaking into smaller ones or sub-watersheds with the topography determining where the water flows. Understanding geomorphology is essential in understanding how watersheds interconnect. Geomorphology (from Greek: γη ge, "earth" μορφή morfé, "form" and λόγος Logos, "knowledge" ^[4]

Major drainage basins of the world

See also: List of drainage basins

Map

Drainage basins of the principal oceans and seas of the world. This is a list of Ocean, mediterranean sea, River, and Lake Drainage basins larger than 400000 square kilometers (154440 square miles sorted Grey areas are endorheic basins that do not drain to the ocean. An endorheic basin (from Greek endo ‘inside’ + rhein ‘to flow’ also terminal or closed basin) is a closed Drainage basin

Ocean basins

There are numerous drainage basins throughout the world in all sorts of places. The following is a list of some of the major ones:

• The Atlantic Ocean drains approximately 47% of all land in the world. In North America, it directly drains the Saint Lawrence River and Great Lakes basins, the Eastern Seaboard of the United States, the Canadian Maritimes, and most of Newfoundland and Labrador. Saint Lawrence River (in French: fleuve Saint-Laurent; Kahnawáˀkye in Tuscarora, Kaniatarowanenneh meaning big waterway The Laurentian Great Lakes are a chain of freshwater lakes located in eastern North America, on the Canada–United States border. The East Coast of the United States, also known as the "Eastern Seaboard" or "Atlantic Seaboard" refers to the easternmost coastal states in the central and northern The Maritime provinces, called the Maritimes in local English (or the Canadian Maritimes by non-Canadians is a region of Eastern Canada Newfoundland and Labrador (ˈnuːfɨn(dlənd ən(d ˈlæbrəˌdɔr (Terre-Neuve-et-Labrador is a province of Canada, the tenth and latest to join the Confederation It also directly drains nearly all of South America east of the Andes, most of Western and Central Europe, and the greatest portion of western Sub-Saharan Africa. South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a The Andes form the world's longest exposed Mountain range. They lie as a continuous chain of highland along the western coast of South America. Sub-Saharan Africa is a geographical term used to describe the area of the African continent which lies south of the Sahara, or those African countries The three major mediterranean seas of the world also flow to the Atlantic:
  • The American Mediterranean Sea (the Caribbean Sea and Gulf of Mexico) basin includes most of the American interior between the Appalachian and Rocky Mountain ranges, a small part of the Canadian provinces of Alberta and Saskatchewan, eastern Central America, the islands of the Caribbean and the Gulf, and a small part of northern South America. For the Mediterranean Sea between Europe and Africa, see the Mediterranean Sea. For the region see Caribbean. The Caribbean Sea (kəˈrɪbiən or /ˌkærɨˈbiːən/ is a tropical Sea in the Western Hemisphere The Gulf of Mexico ( Spanish: Golfo de México) is the ninth largest Body of water in the world The United States of America —commonly referred to as the Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Alberta (ælˈbɝtə is one of Canada's prairie provinces. It became a province on September 1 1905 Saskatchewan (səˈskætʃəwən) is a prairie province in Canada, which has an area of 588276 South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a
  • The European Mediterranean Sea basin includes much of northern Africa, east-central Africa (through the Nile), southern, central, and eastern Europe, Turkey, and the coastal areas of Israel, Lebanon, and Syria. The Nile (النيل, Ancient Egyptian iteru or Ḥ'pī, Coptic piaro or phiaro) is a major north-flowing River Turkey (Türkiye known officially as the Republic of Turkey ( is a Eurasian Country that stretches For a topic outline on this subject see List of basic Israel topics. Lebanon (ˈlɛbənɒn Arabic: ar لبنان Lubnān) officially the Republic of Lebanon or Lebanese Republic (ar الجمهورية اللبنانية Syria ( سوريّة or) officially the Syrian Arab Republic (Arabic ar الجمهورية العربية السورية
  • The Arctic Ocean basin drains most of Western and Northern Canada east of the Continental Divide, the north shore of Alaska and parts of North Dakota, South Dakota, Minnesota, and Montana in the United States, the north shore of the Scandinavian peninsula in Europe, and much of central and northern Russia. The Arctic Ocean, located in the Northern Hemisphere and mostly in the Arctic north polar region is the smallest and shallowest of the world's five major Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page A continental divide is a line of elevated Terrain which forms a border between two watersheds such that Water falling on one side of the line eventually Alaska ( Аляска Alyaska) is a state in the United States of America, in the northwest of the North American continent North Dakota ( is a state located in the Midwestern and Western regions of the United States of America. South Dakota ( is a state located in the Midwestern region of the United States of America. Minnesota ( Native Americans demonstrated the name to early settlers Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern The Scandinavian Peninsula is a geographic region in northern Europe, consisting principally of the Mainland territories of Norway and Sweden Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending
• The Pacific Ocean drains just over 13% of the land in the world. The Pacific Ocean is the largest of the Earth 's Oceanic divisions Its basin includes much of China, southeastern Russia, Japan, Korea, most of Indonesia and Malaysia, the Philippines, all of the Pacific Islands, the northeast coast of Australia, and the western parts of Canada, the United States (including most of Alaska), Central America, and South America. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending For a topic outline on this subject see List of basic Japan topics. Korea is a geographic area composed of two sovereign countries a civilization and a former state situated on the Korean Peninsula in East Asia. The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia. For the biogeographical region see Malesia Malaysia (məˈleɪʒə or /məˈleɪziə/ is a country that consists of thirteen states and The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP The Pacific Ocean contains an estimated 20000 to 30000 Islands (the exact number has yet to be precisely determined For a topic outline on this subject see List of basic Australia topics. Alaska ( Аляска Alyaska) is a state in the United States of America, in the northwest of the North American continent South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a
• The Indian Ocean drains around 13% of the Earth's land. The Indian Ocean is the third largest of the world's Oceanic divisions covering about 20% of the water on the Earth 's surface It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, Afghanistan and Pakistan, the Indian subcontinent, Burma, and most of Australia. The Red Sea is a Salt water Inlet of the Indian Ocean between Africa and Asia. The Persian Gulf, in the Southwest Asian region is an extension of the Afghanistan /æfˈgænɪstæn/ officially the Islamic Republic of Afghanistan ( Pashto: د افغانستان اسلامي جمهوریت, Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and This article deals with the geophysical region in Asia For geopolitical treatments see South Asia. Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. For a topic outline on this subject see List of basic Australia topics.
• The Southern Ocean drains Antarctica. The Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of Antarctica comprises approximately eight percent of the Earth's land.

Endorheic drainage basins

Endorheic basin in Central Asia

Main article: Endorheic basin

Endorheic drainage basins are inland basins that do not drain into an ocean; around 18% of all land drains to endorheic lakes or seas. An endorheic basin (from Greek endo ‘inside’ + rhein ‘to flow’ also terminal or closed basin) is a closed Drainage basin Central Asia is a region of Asia from the Caspian Sea in the west to central China in the east and from southern Russia in the north to northern Pakistan in the south An endorheic basin (from Greek endo ‘inside’ + rhein ‘to flow’ also terminal or closed basin) is a closed Drainage basin An endorheic basin (from Greek endo ‘inside’ + rhein ‘to flow’ also terminal or closed basin) is a closed Drainage basin The largest of these consists of much of the interior of Asia, and drains into the Caspian Sea and the Aral Sea. The Caspian Sea is the largest enclosed body of water on Earth by area variously classed as the world's largest lake or a full-fledged Sea. The Aral Sea ( Kazakh: Арал Теңізі Aral Tengizi, Orol dengizi Russian: Аральскοе мοре Tajik / Persian: Daryocha-i Other basins include the Great Basin in the United States, much of the Sahara Desert, the watershed of the Okavango River (Kalahari Basin), highlands near the African Great Lakes, the interiors of Australia and the Arabian Peninsula, and parts in Mexico and the Andes. The Great Basin is a large arid region of the western United States. The United States of America —commonly referred to as the The Sahara (الصحراء الكبرى aṣ-ṣaḥrā´ al-kubra, "The Great Desert" is the world's largest hot Desert and the world's second largest The Okavango River is a River in southwest Africa. It is the fourth-longest river system in southern Africa running southeastward for 1600 km (1000 miles The Kalahari Basin (or Kalahari Depression) is a large lowland area covering over 2 The Great Lakes of Africa are a series of Lakes in and around the geographic Great Rift Valley formed by the action of the tectonic East African For a topic outline on this subject see List of basic Australia topics. The Arabian Peninsula (in Arabic: شبه الجزيرة العربية šibh al-jazīra al-ʻarabīya or جزيرة العرب jazīrat al-ʻarab) The United Mexican States ( or commonly Mexico (ˈmɛksɪkoʊ () is a federal constitutional Republic in North America. The Andes form the world's longest exposed Mountain range. They lie as a continuous chain of highland along the western coast of South America.

Importance of drainage basins

Geopolitical boundaries

Drainage basins have been important historically in determining 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 Indian Trade in the entire Hudson Bay watershed, an area called Rupert's Land. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland The fur trade is a worldwide industry dealing in the acquisition and sale of animal Fur. Rupert's Land, also sometimes called "Prince Rupert's Land" was a territory in British North America, consisting of the Hudson Bay drainage basin, that The company later acquired the North American watershed of the Arctic Ocean (the North-Western Territory). The Arctic Ocean, located in the Northern Hemisphere and mostly in the Arctic north polar region is the smallest and shallowest of the world's five major For other geographical names that use the term "Northwest" see Northwest. These lands later became part of Canada as the Northwest Territories, making up the vast majority of Canada's land area. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page The Northwest Territories (ˌnɔrθˌwɛstˈtɛrɨtɔriz ( NWT or NT; French, les Territoires du Nord-Ouest) is a territory

Currently the Sistan Basin stretches over the southern parts of Afghanistan and Iran. The Sistan Basin is an inland Endorheic basin encompassing large parts of south-western Afghanistan and south-eastern Iran, one of the driest regions in Afghanistan /æfˈgænɪstæn/ officially the Islamic Republic of Afghanistan ( Pashto: د افغانستان اسلامي جمهوریت, For a topic outline on this subject see List of basic Iran topics.

Shangrila Lake in Skardu Pakistan. Shangrila Lake or Lower Kachura Lake is a part of the Shangrila resort located at a drive of about 20 minutes from Skardu (nearly 2500 m or 8200 feet town Skardu ( Urdu: سکردو is the principal town of the region Baltistan and the capital of Skardu District, one of the districts making up Pakistan's Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and

Today, bioregional democracy can include agreements of states in a particular drainage basin to defend it. Bioregionalism is a term used to describe a political cultural and environmental system based on naturally-defined areas called bioregions or Ecoregions Bioregions are defined These include the Great Lakes Commission. The Great Lakes Commission is an eight-state compact United States agency established in 1955 through the Great Lakes Basin Compact, in order

Hydrology

Drainage basin of the Ohio River, part of the Mississippi River drainage basin. The Ohio River is the largest Tributary by volume of the Mississippi River. The Mississippi River is the second longest River in the United States, with a length of from its source in Lake Itasca in Minnesota to

In hydrology, the drainage basin is a logical unit of focus for studying the movement of water within the hydrological cycle, because the majority of water that discharges from the basin outlet originated as precipitation falling on the basin. Hydrology (from Greek Yδωρ hudōr, "water" and λόγος logos, "study" is the study of the movement distribution and quality of The Earth 's Water is always in movement and the water cycle, also known as the hydrologic cycle, describes the continuous movement of water on above In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric A portion of the water that enters the groundwater system beneath the drainage basin may flow towards the outlet of another drainage basin because groundwater flow directions do not always match those of their overlying drainage network. Measurement of the discharge of water from a basin may be made by a stream gauge located at the basin's outlet. A stream gauge, or stream gage, refers to a site along a Stream where measurements of volumetric discharge (flow are made

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 arithmetic mean method will give good results. In Mathematics and Statistics, the arithmetic Mean (or simply the mean) of a list of numbers is the sum of all the members of the list divided In the Thiessen polygon method, the watershed is divided into polygons with the rain gauge in the middle of each polygon assumed to be representative for the rainfall on the area of land included in its polygon. In Mathematics, a Voronoi diagram, named after Georgy Voronoi, also called a Voronoi Tessellation, a Voronoi decomposition, or These polygons are made by drawing lines between gauges, then making perpendicular bisectors of those lines form the polygons. The isohyetal method involves contours of equal precipitation are drawn over the gauges on a map. A contour line (also Level set, isopleth, isoline, isogram or isarithm) of a function of two Calculating the area between these curves and adding up the volume of water is time consuming.

Ecology

The Mississippi River drains the largest area of any U.S. river, much of it agricultural regions. The Mississippi River is the second longest River in the United States, with a length of from its source in Lake Itasca in Minnesota to The United States of America —commonly referred to as the Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Agricultural runoff and other water pollution that flows to the outlet is the cause of the dead zone in the Gulf of Mexico. This page is about the oceanic phenomenon see Dead Zone for other uses The Gulf of Mexico ( Spanish: Golfo de México) is the ninth largest Body of water in the world

Drainage basins are important elements to consider also in ecology. Ecology (from Greek grc οἶκος oikos, "house(hold" and grc -λογία -logia) is the scientific study of As water flows over the ground and along rivers it can pick up nutrients, sediment, and pollutants. Water pollution is the contamination of Water bodies such as Lakes Rivers Oceans and Groundwater caused by human activities Like the water, they get transported towards the outlet of the basin, and can affect the ecological processes along the way as well as in the receiving water source.

Modern usage of artificial fertilizers, containing nitrogen, phosphorus, and potassium, has affected the mouths of watersheds. The minerals will be carried by the watershed to the mouth and accumulate there, disturbing the natural mineral balance.

Resource management

Further information: Watershed 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. Watershed management is the process of creating and implementing plans programs and projects to sustain and enhance watershed functions that affect the Plant In the U.S. state of Minnesota, governmental entities that perform this function are called watershed districts. A US state is any one of the fifty subnational entities of the United States of America that share Sovereignty with the federal government Minnesota ( Native Americans demonstrated the name to early settlers Watershed districts are special Government entities in the US In New Zealand, they are called catchment boards. Comparable community groups based in Ontario, Canada, are called conservation authorities. In North America this function is referred to as watershed management. Watershed management is the process of creating and implementing plans programs and projects to sustain and enhance watershed functions that affect the Plant In Brazil, the National Policy of Water Resources, regulated by Act n° 9. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld 433 of 1997, establishes the drainage basin as territorial division of Brazilian water management.

See also

• Drainage system
• Mainstem
• Reservoir

Footnotes

References

• DeBarry,Paul A. (2004). Watersheds: Processes, Assessment and Management. John Wiley & Sons.

External links

• New Mexico State University - Water Task Force
• Recommended Watershed Terminology
• A detailed map of watersheds in North America
• Science in Your Watershed, USGS
• Studying Watersheds: A Confluence of Important Ideas
• Water Sustainability Project Sustainable water management through demand management and ecological governance, with the POLIS Project at the University of Victoria
• Map of the Earth's primary watersheds, WRI
• What is a watershed and why should I care?
• Cycleau - A project looking at approaches to managing catchments in North West Europe
• American Water Resources Association
• Map of Watersheds.gif Watersheds of North America