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Gilgel Abay
Gilgel Abay (ግልገል አባይ, Gǝlgäl Abbay), or Lesser Abay, is a river of central Ethiopia. Rising in the mountains of Gojjam, it flows northward to empty into south-western Lake Tana at . Tributaries of the Gilgel Abbay include the Ashar, Jamma, Kelti and the Koger. It was regarded as the true source of the Nile for a long time and the Jesuit priest Pedro Paez visited it in 1618. The name Gilgel Abbay means Lesser Nile, as Abbay is the name for the Blue Nile. Characteristics It is a meandering river, with a catchment area of 3887 km³. Near its mouth it is 71 meter wide, with a slope gradient of 0.7 metre per kilometre. The average diameter of the bed material load, bed material is 0.37 mm (sand). Sediment transport The river transports carries annually 22,185 tonnes of bedload and 7.6 million tonnes of suspended sediment to Lake Tana. See also * List of Ethiopian rivers References Further reading * S. Uhlenbrook, Y. Mohamed, and A. S. Gragne, "Analyzin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east and northeast, Kenya to the south, South Sudan to the west, and Sudan to the northwest. Ethiopia has a total area of . As of 2022, it is home to around 113.5 million inhabitants, making it the 13th-most populous country in the world and the 2nd-most populous in Africa after Nigeria. The national capital and largest city, Addis Ababa, lies several kilometres west of the East African Rift that splits the country into the African and Somali tectonic plates. Anatomically modern humans emerged from modern-day Ethiopia and set out to the Near East and elsewhere in the Middle Paleolithic period. Southwestern Ethiopia has been proposed as a possible homeland of the Afroasiatic langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gojjam
Gojjam ( ''gōjjām'', originally ጐዛም ''gʷazzam'', later ጐዣም ''gʷažžām'', ጎዣም ''gōžžām'') is a historical province in northwestern Ethiopia, with its capital city at Debre Marqos. Gojjam's earliest western boundary extended up unto the triangle to ancient Meroë in Sudan. By 1700, Gojjam's western neighbors were Agawmeder in the southwest and Qwara in the northwest. Agawmeder, never an organized political entity, was gradually absorbed by Gojjam until it reached west to the Sultanate of Gubba; Juan Maria Schuver noted in his journeys in Agawmeder (September 1882) that in three prior months, "the Abyssinians considerably advanced their frontier towards the West, effacing what was left of the independent regions." Gubba acknowledged its dependence to Emperor Menelik II in 1898, but by 1942 was absorbed into Gojjam. Dek Island in Lake Tana was administratively part of Gojjam until 1987. History The ancient history of Gojjam is mostly associated with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Tana
Lake Tana ( am, ጣና ሐይቅ, T’ana ḥāyik’i; previously Tsana) is the largest lake in Ethiopia and the source of the Blue Nile. Located in Amhara Region in the north-western Ethiopian Highlands, the lake is approximately long and wide, with a maximum depth of , and an elevation of . Lake Tana is fed by the Gilgel Abay, Reb and Gumara rivers. Its surface area ranges from , depending on season and rainfall. The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile. This controls the flow to the Blue Nile Falls (Tis Abbai) and hydro-power station. In 2015, the Lake Tana region was nominated as a UNESCO Biosphere Reserve recognizing its national and international natural and cultural importance. Overview Lake Tana was formed by volcanic activity, blocking the course of inflowing rivers in the early Pleistocene epoch, about 5 million years ago. The lake was originally much larger than it is today. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nile
The Nile, , Bohairic , lg, Kiira , Nobiin language, Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the List of rivers by length, longest river in the world, though this has been contested by research suggesting that the Amazon River is slightly longer.Amazon Longer Than Nile River, Scientists Say Of the world's major rivers, the Nile is one of the smallest, as measured by annual flow in cubic metres of water. About long, its drainage basin covers eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Erit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedro Paez
Pedro is a masculine given name. Pedro is the Spanish, Portuguese, and Galician name for ''Peter''. Its French equivalent is Pierre while its English and Germanic form is Peter. The counterpart patronymic surname of the name Pedro, meaning "son of Peter" (compare with the English surname Peterson) is Pérez in Spanish, and Peres in Galician and Portuguese, Pires also in Portuguese, and Peiris in coastal area of Sri Lanka (where it originated from the Portuguese version), with all ultimately meaning "son of Pêro". The name Pedro is derived via the Latin word "petra", from the Greek word "η πέτρα" meaning "stone, rock". The name Peter itself is a translation of the Aramaic ''Kephas'' or '' Cephas'' meaning "stone". An alternate archaic spelling is ''Pêro''. Pedro may refer to: Notable people Monarchs, mononymously *Pedro I of Portugal *Pedro II of Portugal *Pedro III of Portugal *Pedro IV of Portugal, also Pedro I of Brazil *Pedro V of Portugal *Pedro II of Bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Nile
The Blue Nile (; ) is a river originating at Lake Tana in Ethiopia. It travels for approximately through Ethiopia and Sudan. Along with the White Nile, it is one of the two major tributaries of the Nile and supplies about 85.6% of the water to the Nile during the rainy season. Course The distance of the river from its source to its confluence has been variously reported as being between and . This uncertainty might result from the fact that the river flows through a series of virtually impenetrable gorges cut in the Ethiopian Highlands to a depth of some . According to materials published by the Central Statistical Agency, the Blue Nile has a total length of , of which are inside Ethiopia. In Ethiopia The Blue Nile originates at Lake Tana in Ethiopia (where it is called the Abay River). The river flows generally south before entering a canyon about long, about from Lake Tana, which is a tremendous obstacle for travel and communication between north and south Ethiop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meander
A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank which is typically a point bar. The result of this coupled erosion and sedimentation is the formation of a sinuous course as the channel migrates back and forth across the axis of a floodplain. The zone within which a meandering stream periodically shifts its channel is known as a meander belt. It typically ranges from 15 to 18 times the width of the channel. Over time, meanders migrate downstream, sometimes in such a short time as to create civil engineering challenges for local municipalities attempting to maintain stable roads and bridges.Neuendorf, K.K.E., J.P. Mehl Jr., and J.A. Jackson, J.A., eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. Charlton, R., 2007. ''Fundamentals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bed Material Load
Three components that are included in the load of a river system are the following: dissolved load, wash load and bed material load. The bed material load is the portion of the sediment that is transported by a stream that contains material derived from the bed. Bed material load typically consists of all of the bed load, and the proportion of the suspended load that is represented in the bed sediments. It generally consists of grains coarser than 0.062 mm with the principal source being the channel bed. Its importance lies in that its composition is that of the bed, and the material in transport can therefore be actively interchanged with the bed. For this reason, bed material load exerts a control on river channel morphology. Bed load and wash load Wash load is similar to a suspended load, but wash load sediment never interacts with the bed load. All of the sediment in the wash load stays suspended in the water throughout the channel (this concept has been debated). Wash load ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand, for example, aragonite, which has mostly been created, over the past 500million years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Somewhat more rarely, sand may be composed of calciu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedload
The term bed load or bedload describes particles in a flowing fluid (usually water) that are transported along the stream bed. Bed load is complementary to suspended load and wash load. Bed load moves by rolling, sliding, and/or saltating (hopping). Generally, bed load downstream will be smaller and more rounded than bed load upstream (a process known as downstream fining). This is due in part to attrition and abrasion which results from the stones colliding with each other and against the river channel, thus removing the rough texture (rounding) and reducing the size of the particles. However, selective transport of sediments also plays a role in relation to downstream fining: smaller-than average particles are more easily entrained than larger-than average particles, since the shear stress required to entrain a grain is linearly proportional to the diameter of the grain. However, the degree of size selectivity is restricted by the hiding effect described by Parker and Klin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suspended Sediment
The suspended load of a flow of fluid, such as a river, is the portion of its sediment uplifted by the fluid's flow in the process of sediment transportation. It is kept suspended by the fluid's turbulence. The suspended load generally consists of smaller particles, like clay, silt, and fine sands''.'' Sediment transportation The suspended load is one of the three layers of the fluvial sediment transportation system. The bed load consists of the larger sediment which is transported by saltation, rolling, and dragging on the riverbed. The suspended load is the middle layer that consists of the smaller sediment that's suspended. The wash load is uppermost layer which consist of the smallest sediment that can be seen with the naked eye; however, the wash load gets easily mixed with suspended load during transportation due to the very similar process. The wash load never touches the bed even outside of a current. Composition The boundary between bed load and suspended load is not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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