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Lake Chad
Lake Chad (french: Lac Tchad) is a historically large, shallow, endorheic lake in Central Africa, which has varied in size over the centuries. According to the ''Global Resource Information Database'' of the United Nations Environment Programme, it shrank by as much as 95% from about 1963 to 1998. The lowest area was in 1986, at , but "the 2007 (satellite) image shows significant improvement over previous years." Lake Chad is economically important, providing water to more than 30 million people living in the four countries surrounding it (Chad, Cameroon, Niger, and Nigeria) on the central part of the Sahel. It is the largest lake in the Chad Basin. Geography and hydrology The freshwater lake is located in the Sahelian zone of West-central Africa. It is located in the interior basin which used to be occupied by a much larger ancient sea sometimes called Mega Chad. The lake is historically ranked as one of the largest lakes in Africa. Its surface area varies by season as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apollo 7
Apollo 7 (October 1122, 1968) was the first crewed flight in NASA's Apollo program, and saw the resumption of human spaceflight by the agency after the fire that killed the three Apollo 1 astronauts during a launch rehearsal test on January 27, 1967. The Apollo7 crew was commanded by Walter M. Schirra, with command module pilot Donn F. Eisele and lunar module pilot R. Walter Cunningham (so designated even though Apollo7 did not carry a Lunar Module). The three astronauts were originally designated for the second crewed Apollo flight, and then as backups for Apollo1. After the Apollo1 fire, crewed flights were suspended while the cause of the accident was investigated and improvements made to the spacecraft and safety procedures, and uncrewed test flights made. Determined to prevent a repetition of the fire, the crew spent long periods monitoring the construction of their Apollo command and service modules (CSM). Training continued over much of the pause that followe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yobe River
The Yobe River, also known as the Komadougou Yobe or the Komadougou-Yobe (french: Komadougou Yobé), is a river in West Africa that flows into Lake Chad through Nigeria and Niger. Its tributaries include the Hadejia River, the Jama'are River, and the Komadugu Gana River. The river forms a small part of the international border between Niger and Nigeria. There are concerns about changes in the river flow, economy and ecology due to upstream dams, the largest at present being the Tiga Dam in Kano State, with plans being discussed for the Kafin Zaki Dam in Bauchi State. Notable towns near the river include Gashua, Geidam, and Damasak Damasak is the head town of the Mobbar Local Government Area, in the northeastern Nigerian state of Borno. It is located near the confluence of the Yobe River and Komadugu Gana River,Mortimore, MichaelAdapting to Drought: Farmers, Famines, and ... in Nigeria, and Diffa in Niger. See also * Yobe State * Hadejia-Nguru wetlands Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspian Sea
The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia, south of the fertile plains of Southern Russia in Eastern Europe, and north of the mountainous Iranian Plateau of Western Asia. It covers a surface area of (excluding the highly saline lagoon of Garabogazköl to its east) and a volume of . It has a salinity of approximately 1.2% (12 g/L), about a third of the salinity of average seawater. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the southwest, Iran to the south, and Turkmenistan to the southeast. The sea stretches nearly from north to south, with an average width of . Its gross coverage is and the surface is about below sea level. Its main freshwater inflow, Europe's longest river, the Volga, enters at the shallow north end. Two deep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Humid Period
The African humid period (AHP) (also known by other names) is a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today. The covering of much of the Sahara desert by grasses, trees and lakes was caused by changes in Earth's orbit around the Sun; changes in vegetation and dust in the Sahara which strengthened the African monsoon; and increased greenhouse gases. During the preceding Last Glacial Maximum, the Sahara contained extensive dune fields and was mostly uninhabited. It was much larger than today, but its lakes and rivers such as Lake Victoria and the White Nile were either dry or at low levels. The humid period began about 14,600–14,500 years ago at the end of Heinrich event 1, simultaneously to the Bølling–Allerød warming. Rivers and lakes such as Lake Chad formed or expanded, glaciers grew on Mount Kilimanjaro and the Sahara retreated. Two major dry fluctuations occurred; during the Younger Dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inland Sea (geology)
An inland sea (also known as an epeiric sea or an epicontinental sea) is a continental body of water which is very large and is either completely surrounded by dry land or connected to an ocean by a river, strait, or "arm of the sea". An inland sea will generally have higher salinity than a freshwater lake, but usually lower salinity than the open ocean. Definition What constitutes an "inland sea" is complex and somewhat necessarily vague. The United States Hydrographic Office defined it as "a body of water nearly or completely surrounded by land, especially if very large or composed of salt water". Geologic engineers Heinrich Ries and Thomas L. Watson say an inland sea is merely a very large lake. Rydén, Migula, and Andersson and Deborah Sandler of the Environmental Law Institute add that an inland sea is "more or less" cut off from the ocean. It may be semi-enclosed, or connected to the ocean by a strait or "arm of the sea". An inland sea is distinguishable from a bay in tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kanuri Language
Kanuri () is a dialect continuum spoken in Nigeria, Niger, Chad and Cameroon, as well as in small minorities in southern Libya and by a diaspora in Sudan. Background At the turn of the 21st century, its two main dialects, Manga Kanuri and Yerwa Kanuri (also called Beriberi, which its speakers consider to be pejorative), were spoken by 9,700,000 people in Central Africa. It belongs to the Western Saharan subphylum of Nilo-Saharan. Kanuri is the language associated with the Kanem and Bornu empires that dominated the Lake Chad region for a thousand years. The basic word order of Kanuri sentences is subject–object–verb. It is typologically unusual in simultaneously having postpositions and post-nominal modifiers – for example, "Bintu's pot" would be expressed as ''nje Bintu-be'', "pot Bintu-of". Kanuri has three tones: high, low, and falling. It has an extensive system of consonantal lenition; for example, "they" + "have eaten" → "they have eaten". Traditionally a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percolate
Percolation (from Latin ''percolare'', "to filter" or "trickle through"), in physics, chemistry and materials science, refers to the movement and filtering of fluids through porous materials. It is described by Darcy's law. Broader applications have since been developed that cover connectivity of many systems modeled as lattices or graphs, analogous to connectivity of lattice components in the filtration problem that modulates capacity for percolation. Background During the last decades, percolation theory, the mathematical study of percolation, has brought new understanding and techniques to a broad range of topics in physics, materials science, complex networks, epidemiology, and other fields. For example, in geology, percolation refers to filtration of water through soil and permeable rocks. The water flows to recharge the groundwater in the water table and aquifers. In places where infiltration basins or septic drain fields are planned to dispose of substantial amoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bahr El-Ghazal (wadi In Chad)
The Bahr el-Ghazal (بحر الغزال) is a wadi, or dry riverbed, in central Chad. When water flows through it (which in modern times happens only in rare, extreme rainfall events), it flows from southwest to northeast, away from Lake Chad and into the Bodélé Depression The Bodélé Depression (), located at the southern edge of the Sahara Desert in north central Africa, is the lowest point in Chad. It is 500 km long, 150 km wide and around 160 m deep. Its bottom lies about 155 meters above sea leve .... The "sill" of the Bahr el-Ghazal is the lowest point on the drainage divide between the Lake Chad and Bodélé basins. In the past, when Lake Chad filled to this point and overflowed, it was drained by the Bahr el-Ghazal. References Rivers of Chad Bahr el Ghazal {{Chad-river-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Chad Flooded Savanna
The Lake Chad flooded savanna is a flooded grasslands and savannas ecoregion in Africa. It includes the seasonally- and permanently-flooded grasslands and savannas in the basin of Lake Chad in Central Africa, and covers portions of Cameroon, Chad, Niger, and Nigeria. Geography Lake Chad is a large shallow lake, lying at the center of a large closed drainage basin, with no outlet to the sea. The Lake Chad basin has an area of . The northern portion of the basin is arid or semi-arid, and the southern portion has a seasonally-dry savanna climate. The flooded savannas surround the lake. The Chari and Logone rivers, which drain northwards from the highlands along the basin's southern edge, supply 95% of Lake Chad's freshwater. The Yobe River, which flows eastwards into the lake's northern end, contributes 2.5% of the lake's inflow. Accessed 7 July 2020. Despite having no outlet, Lake Chad has relatively low salinity. The saltier waters sink to the bottom of the lake, and drain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marshes
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs, and the marsh is sometimes called a carr. This form of vegetation is what differentiates marshes from other types of wetland such as swamps, which are dominated by trees, and mires, which are wetlands that have accumulated deposits of acidic peat. Marshes provide habitats for many kinds of invertebrates, fish, amphibians, waterfowl and aquatic mammals. This biological productivity means that marshes contain 0.1% of global sequestered terrestrial carbon. Moreover, they have an outsized influence on climate resi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swampland
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in creating this environment. Swamps vary in size and are located all around the world. The water of a swamp may be fresh water, brackish water, or seawater. Freshwater swamps form along large rivers or lakes where they are critically dependent upon rainwater and seasonal flooding to maintain natural water level fluctuations.Hughes, F.M.R. (ed.). 2003. The Flooded Forest: Guidance for policy makers and river managers in Europe on the restoration of floodplain forests. FLOBAR2, Department of Geography, University of Cambridge, Cambridge, UK. 96 p. Saltwater swamps are found along tropical and subtropical coastlines. Some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bank (geography)
In geography, a bank is the land alongside a body of water. Different structures are referred to as ''banks'' in different fields of geography, as follows. In limnology (the study of inland waters), a stream bank or river bank is the terrain alongside the bed of a river, creek, or stream. The bank consists of the sides of the channel, between which the flow is confined. Stream banks are of particular interest in fluvial geography, which studies the processes associated with rivers and streams and the deposits and landforms created by them. Bankfull discharge is a discharge great enough to fill the channel and overtop the banks. The descriptive terms ''left bank'' and ''right bank'' refer to the perspective of an observer looking downstream; a well-known example of this being the sections of Paris as defined by the river Seine. The shoreline of ponds, swamps, estuaries, reservoirs, or lakes are also of interest in limnology and are sometimes referred to as banks. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
