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42-789: The organization's secretariat is located in N'Djamena , Chad. The LCBC is Africa's oldest river or lake-basin organization. In its founding document (the Convention and Statutes relating to the Development of the Chad Basin) the parties commit themselves to a shared use of the basin's natural resources. It is a member of the International Network of Basin Organizations (INBO). The Lake Chad Basin Commission

84-540: 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 , 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 . Other terms for a drainage basin are catchment area , catchment basin , drainage area , river basin , water basin , and impluvium . In North America, they are commonly called

126-484: A sink , which may be a permanent lake, a dry lake , or a point where surface water is lost underground . Drainage basins are similar but not identical to hydrologic units , 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. About 48.71% of

168-414: A watershed , though in other English-speaking places, "watershed" is used only in its original sense, that of the drainage divide line. A drainage basin's boundaries are determined by watershed delineation , a common task in environmental engineering and science. In a closed drainage basin, or endorheic basin , rather than flowing to the ocean, water converges toward the interior of the basin, known as

210-454: A drainage basin, and there are different ways to interpret that data. In the unlikely event that the gauges are many and evenly distributed over an area of uniform precipitation, using the arithmetic mean method will give good results. In the Thiessen polygon method, the drainage basin is divided into polygons with the rain gauge in the middle of each polygon assumed to be representative for

252-540: A drainage boundary is referred to as watershed delineation . Finding the area and extent of a drainage basin is an important step in many areas of science and engineering. Most of the water that discharges from the basin outlet originated as precipitation falling on the basin. 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

294-540: A long tradition of well-established river basin organizations (see fr:Agence de l'eau and es:Confederación hidrográfica ), are represented both at the Ministerial level and by river basin organizations. Algeria, Brazil and Mexico , which have all established river basin organizations during the 1990s, are represented both by institutions at the national and at the basin level. As of 2000 INBO had no members from China, Egypt , Germany, Nigeria, South Africa, Turkey or

336-487: Is referred to as " watershed management ". In Brazil , the National Policy of Water Resources, regulated by Act n° 9.433 of 1997, establishes the drainage basin as the territorial division of Brazilian water management. 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 transboundary river . Management of such basins becomes

378-614: Is the Dead Sea . 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

420-713: The African Great Lakes , the interiors of Australia and the Arabian Peninsula , and parts in Mexico and the Andes . Some of these, such as the Great Basin, are not single drainage basins but collections of separate, adjacent closed basins. In endorheic bodies of water where evaporation is the primary means of water loss, the water is typically more saline than the oceans. An extreme example of this

462-608: The Chad Basin (not all of which feeds Lake Chad) includes eight countries, which, in descending area of land, included are: Chad , Niger , the Central African Republic , Nigeria , Sudan , Algeria , and Libya . Cameroon , Niger, Nigeria and Chad (the four countries directly containing parts of Lake Chad and its wetlands) signed the Fort Lamy (today N'Djamena ) Convention on May 22, 1964, which created

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504-828: The Continental Divide , northern Alaska and parts of North Dakota , South Dakota , Minnesota , and Montana in the United States, the north shore of the Scandinavian peninsula in Europe, central and northern Russia, and parts of Kazakhstan and Mongolia in Asia , which totals to about 17% of the world's land. Just over 13% of the land in the world drains to the Pacific Ocean . Its basin includes much of China, eastern and southeastern Russia, Japan,

546-667: The Democratic Republic of Congo which are fed by the Ubangi River being considered for diversion into Lake Chad. The member countries fund the commission's $ 1 million annual budget based on an agreed-upon formula: Nigeria 52%, Cameroon 26%, Chad 11%, Niger 7%, the Central African Republic 4%. The commission's Basin Committee for Strategic Planning (BCSP), coordinates local activities between

588-714: The Korean Peninsula , most of Indochina, Indonesia and Malaysia, the Philippines, all of the Pacific Islands , the northeast coast of Australia , and Canada and the United States west of the Continental Divide (including most of Alaska), as well as western Central America and South America west of the Andes. The Indian Ocean 's drainage basin also comprises about 13% of Earth's land. It drains

630-528: The Mediterranean (MENBO, created in 2003), Asia (NARBO, created in 2004), Latin America (LANBO, created in 2008) and North America (NANBO, created in 2009). This article about an international organization is a stub . You can help Misplaced Pages by expanding it . Drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as

672-611: The Lake Chad Basin Commission. The Central African Republic joined in 1996, and Libya joined in 2008. Sudan was admitted in July 2000, but has observer status because it has not ratified the founding convention. Algeria has not yet participated, but will eventually be interested in such in the future. The other countries with observer status are Egypt —in the neighboring Nile Basin —and the Republic of Congo and

714-1014: The Mediterranean branch of the Ramsar Convention, and its Coordination Unit, CHADWET is set to be developed on the model of MEDWET, again in the framework of the GEF program. With a view to obtaining funding, there were plans to present the CHADWET to the Ramsar Conference in November 2005 as a Ramsar Regional Initiative. International Network of Basin Organizations The International Network of Basin Organizations ( INBO ) (French: Réseau International des Organismes de Bassin RIOB ). It

756-623: 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 . In hydrology , the drainage basin is a logical unit of focus for studying the movement of water within the hydrological cycle . The process of finding

798-855: The United States, countries which have no or few river basin organizations. INBO includes transboundary basin agencies, such as the Organisation pour la mise en valeur du fleuve Sénégal (OMVS). It also includes several international organizations and partnerships, such as UNEP , UNDP and the Global Water Partnership , as well as regional organization such as the Southern African Development Community (SADC). There are regional networks within INBO. They cover Eastern and Central Europe (CEENBO, created in 2001), Sub-Saharan Africa (ANBO, created in 2002),

840-406: 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. Rain gauge data is used to measure total precipitation over

882-430: The discharge of water from a basin may be made by a stream gauge located at the basin's outlet. Depending on the conditions of the drainage basin, as rainfall occurs some of it seeps directly into the ground. This water will either remain underground, slowly making its way downhill and eventually reaching the basin, or it will permeate deeper into the soil and consolidate into groundwater aquifers. As water flows through

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924-441: 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

966-697: The drainage basin to the mouth, and may accumulate there, disturbing the natural mineral balance. This can cause eutrophication where plant growth is accelerated by the additional material. 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 U.S. state of Minnesota , governmental entities that perform this function are called " watershed districts ". In New Zealand, they are called catchment boards. Comparable community groups based in Ontario, Canada, are called conservation authorities . In North America, this function

1008-857: The eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf , the Indian subcontinent , Burma, and most parts of Australia . The five largest river basins (by area), from largest to smallest, are those of the Amazon (7 million km ), the Congo (4 million km ), the Nile (3.4 million km ), the Mississippi (3.22 million km ), and the Río de la Plata (3.17 million km ). The three rivers that drain

1050-543: The general public for water resources management. It also promotes the twinning of basin organizations from different countries, including the exchange of staff. INBO and its member organizations support the application of Integrated water resources management As of 2000 INBO included 134 members or observers. Some countries are represented by a government Ministry, whether these countries have established river basin organizations (such as Morocco) or not (such as India). Other countries, notably France and Spain which both have

1092-583: The greatest portion of western Sub-Saharan Africa , as well as Western Sahara and part of Morocco . The two major mediterranean seas of the world also flow to the Atlantic. The Caribbean Sea and Gulf of Mexico basin includes most of the U.S. interior between the Appalachian and Rocky Mountains , a small part of the Canadian provinces of Alberta and Saskatchewan , eastern Central America ,

1134-435: The ground and along rivers it can pick up nutrients , sediment , and pollutants . With the water, they are transported towards the outlet of the basin, and can affect the ecological processes along the way as well as in the receiving water body . Modern use of artificial fertilizers , containing nitrogen (as nitrates ), phosphorus , and potassium , has affected the mouths of drainage basins. The minerals are carried by

1176-781: The ground at its terminus, the area can go by several names, such playa, salt flat, dry lake , or alkali sink . The largest endorheic basins are in Central Asia , including the Caspian Sea , the Aral Sea , and numerous smaller lakes. Other endorheic regions include the Great Basin in the United States, much of the Sahara Desert , the drainage basin of the Okavango River ( Kalahari Basin ), highlands near

1218-639: The islands of the Caribbean and the Gulf, and a small part of northern South America. The Mediterranean Sea basin, with the Black Sea , includes much of North Africa , east-central Africa (through the Nile River ), Southern , Central, and Eastern Europe , Turkey , and the coastal areas of Israel , Lebanon , and Syria . The Arctic Ocean drains most of Western Canada and Northern Canada east of

1260-671: The member states. The LCBC controls the hydro-active regions in the Chad Basin, called the Conventional Basin . The initial Conventional Basin consisted of approximately 427,500 km of the total area of the Chad basin in 1964. The definition says it excluded the majority of the terminal depression consisting of desert that provides little or no effective hydrological contribution to the Conventional Basin. This

1302-514: The most water, from most to least, are the Amazon, Ganges , and Congo rivers. Endorheic basin are inland basins that do not drain to an ocean. Endorheic basins cover around 18% of the Earth's land. Some endorheic basins drain to an Endorheic lake or Inland sea . Many of these lakes are ephemeral or vary dramatically in size depending on climate and inflow. If water evaporates or infiltrates into

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1344-418: The rainfall on the area of land included in its polygon. 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. Calculating the area between these curves and adding up the volume of water is time-consuming. Isochrone maps can be used to show

1386-631: The responsibility of the countries sharing it. Nile Basin Initiative , OMVS for Senegal River , Mekong River Commission are a few examples of arrangements involving management of shared river basins. Management of shared drainage basins is also seen as a way to build lasting peaceful relationships among countries. The catchment is the most significant factor determining the amount or likelihood of flooding . Catchment factors are: topography , shape, size, soil type, and land use (paved or roofed areas). Catchment topography and shape determine

1428-461: 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. 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

1470-418: The speed with which the runoff reaches a river. A long thin catchment will take longer to drain than a circular catchment. 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 will help determine how much water reaches the river. The runoff from

1512-415: 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. 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 will contribute to

1554-477: The time taken for runoff water within a drainage basin to reach a lake, reservoir or outlet, assuming constant and uniform effective rainfall. Drainage basins are the principal hydrologic unit considered in fluvial geomorphology . A drainage basin is the source for water and sediment that moves from higher elevation through the river system to lower elevations as they reshape the channel forms. Drainage basins are important in ecology . As water flows over

1596-673: The world's land drains to the Atlantic Ocean . In North America , surface water drains to the Atlantic via the Saint Lawrence River and Great Lakes basins, the Eastern Seaboard of the United States, the Canadian Maritimes , and most of Newfoundland and Labrador . Nearly all of South America east of the Andes also drains to the Atlantic, as does most of Western and Central Europe and

1638-642: Was created in 1964 by the four countries bordering Lake Chad: Cameroon, Chad, Niger and Nigeria. The Republic of Central Africa joined the organization in 1996, Libya was admitted in 2008. Observer status is held by Sudan, Egypt, the Republic of Congo and the Democratic Republic of Congo. The aims of the commission are to regulate and control the use of water and other natural resources in the basin and to initiate, promote, and coordinate natural resource development projects and research. Hydrologically,

1680-636: Was declared a Transboundary Ramsar Site of International Importance). The aim is to create a network of national and regional conservation areas in the Chad Basin and to set up institutions dedicated to their sustainable management . In this connection the Chad Wetlands Initiative (CHADWET) was launched in June 2003, organized by the Ramsar Bureau and its Mediterranean Coordination Unit. With the support of MEDWET (Mediterranean Wetlands),

1722-453: Was established in 1994 and its headquarters is in Paris. Its objective is to promote the exchange of experiences between organizations in charge of river basin management in such areas as institutional and financial management, knowledge of water resources, training different stakeholders involved in water management as well as the staff of basin organizations, and increasing the awareness of

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1764-622: Was subsequently expanded to include additional watersheds in northern Nigeria, southern Chad, and northern Central African Republic, with a current total area of 967,000 km. Some projects of the LCBC member countries are linked with the GEF program . In November 2002, the LCBC signed a Memorandum of Understanding with the Bureau of the Ramsar Convention on Wetlands . In July 2000, Lake Chad

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