1.
White water
–
The term is also loosely used to refer to less turbulent, but still agitated, flows. The term whitewater also has a meaning, applying to any river or creek itself that has a significant number of rapids. The term is used as an adjective describing boating on such rivers. Four factors, separately or in combination, can create rapids, gradient, constriction, obstruction, gradient, constriction and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams, streambed topography is the primary factor in creating rapids, and is generally consistent over time. The gradient of a river is the rate at which it loses elevation along its course and this loss determines the rivers slope, and to a large extent its rate of flow. Shallow gradients produce gentle, slow rivers while steep gradients are associated with raging torrents, constrictions can form a rapid when a rivers flow is forced into a narrower channel. This pressure causes the water to more rapidly and to react differently to riverbed events. As with hydraulics, the power of eddies increases with the flow rate, in large rivers with high flow rates next to an obstruction, eddy walls can occur. An eddy wall is formed when the height of the river is higher than the level of the water in the eddy behind the obstruction. A marked increase or decrease in flow can create a rapid, flow rate is typically measured in cubic metres per second, or in cubic feet per second, depending on the country. The most widely used grading system is the International Scale of River Difficulty, grade-VI rapids are sometimes downgraded to grade-V or V+ if they have been run successfully. Harder rapids are often portaged, a French term for carrying, a portaged rapid is where the boater lands and carries the boat around the hazard. A rapids grade is not fixed, since it may vary depending on the water depth. Although some rapids may be easier at high flows because features are covered or washed-out, high water usually makes rapids more difficult, at flood stage, even rapids which are usually easy can contain lethal and unpredictable hazards. Class 1, Very small rough areas, requires no maneuvering, Class 2, Some rough water, maybe some rocks, small drops, might require maneuvering. Class 3, Medium waves, maybe a 3–5 ft drop, Class 4, Whitewater, large waves, long rapids, rocks, maybe a considerable drop, sharp maneuvers may be needed. Class 5, Whitewater, large waves, continuous rapids, large rocks and hazards, maybe a large drop, often characterized by must make moves, i. e. failure to execute a specific maneuver at a specific point may result in serious injury or death
2.
Rapids
–
Rapids are sections of a river where the river bed has a relatively steep gradient, causing an increase in water velocity and turbulence. Rapids are hydrological features between a run and a cascade, rapids are characterised by the river becoming shallower with some rocks exposed above the flow surface. As flowing water splashes over and around the rocks, air bubbles become mixed in with it and portions of the surface acquire a white colour, forming what is called whitewater. Rapids occur where the bed material is resistant to the erosive power of the stream in comparison with the bed downstream of the rapids. Very young streams flowing across solid rock may be rapids for much of their length, rapids cause water aeration of the stream or river resulting in better water quality. Rapids are categorized in classes, generally running from I to VI, a Class 5 rapid may be categorized as Class 5. 1-5.9. While class I rapids are easy to negotiate and require no maneuvering, river rafting sports is carried out where many rapids are there in the course
3.
Nile
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The Nile is a major north-flowing river in northeastern Africa. It is generally regarded as the longest river in the world, in particular, the Nile is the primary water source of Egypt and Sudan. The Nile has two tributaries, the White Nile and Blue Nile. The White Nile is considered to be the headwaters and primary stream of the Nile itself, the Blue Nile, however, is the source of most of the water and silt. The White Nile is longer and rises in the Great Lakes region of central Africa and it flows north through Tanzania, Lake Victoria, Uganda and South Sudan. The Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast, the two rivers meet just north of the Sudanese capital of Khartoum. The northern section of the river flows north almost entirely through the Sudanese desert to Egypt, then ends in a large delta, Egyptian civilization and Sudanese kingdoms have depended on the river since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of Aswan, in the ancient Egyptian language, the Nile is called Ḥpī or Iteru, meaning river. In Coptic, the words piaro or phiaro meaning the river come from the ancient name. The English name Nile and the Arabic names en-Nîl and an-Nîl both derive from the Latin Nilus and the Ancient Greek Νεῖλος, beyond that, however, the etymology is disputed. One possible etymology derives it from a Semitic Nahal, meaning river, the standard English names White Nile and Blue Nile, to refer to the rivers source, derive from Arabic names formerly applied only to the Sudanese stretches which meet at Khartoum. Above Khartoum, the Nile is also known as the White Nile, at Khartoum the river is joined by the Blue Nile. The White Nile starts in equatorial East Africa, and the Blue Nile begins in Ethiopia, both branches are on the western flanks of the East African Rift. The drainage basin of the Nile covers 3,254,555 square kilometers, the source of the Nile is sometimes considered to be Lake Victoria, but the lake has feeder rivers of considerable size. It is either the Ruvyironza, which emerges in Bururi Province, Burundi, or the Nyabarongo, the two feeder rivers meet near Rusumo Falls on the Rwanda-Tanzania border. Gish Abay is reportedly the place where the water of the first drops of the Blue Nile develop. The Nile leaves Lake Nyanza at Ripon Falls near Jinja, Uganda and it flows north for some 130 kilometers, to Lake Kyoga. For the remaining part it flows westerly through the Murchison Falls until it reaches the very northern shores of Lake Albert where it forms a significant river delta
4.
Aswan
–
Aswan, formerly spelled Assuan, is a city in the south of Egypt, the capital of the Aswan Governorate. Aswan is a market and tourist centre located just north of the Aswan Dams on the east bank of the Nile at the first cataract. The modern city has expanded and includes the separate community on the island of Elephantine. Aswan is the ancient city of Swenett, which in antiquity was the town of Ancient Egypt facing the south. Swenett is supposed to have derived its name from an Egyptian goddess with the same name, the ancient name of the city also is said to be derived from the Egyptian symbol for trade, or market. The city stood upon a peninsula on the bank of the Nile, immediately below the first cataract of the flowing waters. Navigation to the delta was possible from this location without encountering a barrier, the stone quarries of ancient Egypt located here were celebrated for their stone, and especially for the granitic rock called Syenite. They lie on either bank of the Nile, and a road,6.5 km in length, was cut beside them from Syene to Philae, Swenett was equally important as a military station as a place of traffic. Under every dynasty it was a town, and here tolls. Around 330, the legion stationed here received a bishop from Alexandria, the city is mentioned by numerous ancient writers, including Herodotus, Strabo, Stephanus of Byzantium, Ptolemy, Pliny the Elder, Vitruvius, and it appears on the Antonine Itinerary. It also is mentioned in the Book of Ezekiel and the Book of Isaiah, the latitude of the city that would become Aswan – located at 24° 5′ 23″ – was an object of great interest to the ancient geographers. They believed that it was seated immediately under the tropic, and that on the day of the summer solstice and they noted that the suns disc was reflected in a well at noon. However, Eratosthenes used this information together with measurements of the length on the solstice at Alexandria to perform the first known calculation of the circumference of the Earth. The Nile is nearly 650 m wide above Aswan, from this frontier town to the northern extremity of Egypt, the river flows for more than 1,200 km without bar or cataract. The voyage from Aswan to Alexandria usually took 21 to 28 days in favourable weather, Aswan has a hot desert climate like the rest of Egypt. Aswan and Luxor have the hottest summer days of any city in Egypt, Aswan is one of the hottest, sunniest and driest cities in the world. Averages high temperatures are consistently above 40 °C during summer while averages low temperatures remain above 25 °C, summers are long, prolonged and extremely hot. Averages high temperatures remain above 23 °C during the coldest month of the year while averages low temperatures remain above 8 °C, winters are short, brief and extremely warm
5.
Khartoum
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Khartoum is the capital and second largest city of Sudan and the state of Khartoum. It is located at the confluence of the White Nile, flowing north from Lake Victoria, the location where the two Niles meet is known as al-Mogran. The main Nile continues to north towards Egypt and the Mediterranean Sea. The origin of the word, Khartoum, is uncertain, one theory argues that khartoum is derived from Arabic khurṭūm, probably referring to the narrow strip of land extending between the Blue and White Niles. Some scholars speculate that the word derives from the Nubian word, Agartum, other Beja scholars suggest Khartoum is derived from the Beja word, Hartoom. Additionally, the dream interpreting magicians in Genesis 41,8 are referred to as חַרְטֻמֵּ֥י, suggesting that in ancient times the word already existed. In 1821, Khartoum was established 24 kilometres north of the ancient city of Soba, by Ibrahim Pasha, the son of Egypts ruler, Muhammad Ali Pasha, who had just incorporated Sudan into his realm. Originally, Khartoum served as an outpost for the Egyptian Army and it also became a focal point for the slave trade. Later, it became the center of Sudan and official capital. On 13 March 1884, troops loyal to the Mahdi Muhammad Ahmad started a siege of Khartoum, the siege ended in a massacre of the Anglo-Egyptian garrison. On 26 January 1885, the damaged city fell to the Mahdists. On 2 September 1898, Omdurman was the scene of the bloody Battle of Omdurman, in 1973, the city was the site of an anomalous hostage crisis in which members of Black September held 10 hostages at the Saudi Arabian embassy, five of them diplomats. The US ambassador, the US deputy ambassador, and the Belgian chargé daffaires were murdered, a 1973 United States Department of State document, declassified in 2006, concluded, The Khartoum operation was planned and carried out with the full knowledge and personal approval of Yasser Arafat. In 1977, the first oil pipeline between Khartoum and the Port of Sudan was completed, throughout the 1970s and 1980s, Khartoum was the destination for hundreds of thousands of refugees fleeing conflicts in neighboring nations such as Chad, Eritrea, Ethiopia, and Uganda. Many Eritrean and Ethiopian refugees assimilated into society, while others settled in large slums at the outskirts of the city, since the mid-1980s, large numbers of refugees from South Sudan and Darfur fleeing the violence of the Second Sudanese Civil War and Darfur conflict have settled around Khartoum. In 1991, Osama bin Laden purchased a house in the affluent al-Riyadh neighborhood of the city and he lived there until 1996, when he was banished from the country. The destruction of the factory produced diplomatic tension between the U. S. and Sudan, the factory ruins are now a tourist attraction. The sudden death of SPLA head and vice-president of Sudan, John Garang, the riots finally died down after Southern Sudanese politicians and tribal leaders sent strong messages to the rioters
6.
Islet
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An islet is a very small island. As suggested by its origin as islette, an Old French diminutive of isle, use of the term implies small size, but little attention is given to drawing an upper limit on its applicability. Cay or Key – an islet formed by the accumulation of sand deposits atop a reef Motu – A reef islet formed by broken coral and sand. River island – A small islet within the current of a river, rock – A rock, in the sense of a type of islet, is an uninhabited landform composed of rock, lying offshore, and having at most minimal vegetation. Sandbar – An exposed sandbar is another type of islet, Sea stack – A thin, vertical landform jutting out of a body of water. Skerry – A small rocky island, usually defined to be too small for habitation, subsidiary islets – A more technical application is to small land features, isolated by water, lying off the shore of a larger island. Likewise, any emergent land in an atoll is called an islet. Tidal island – Often small islands lie off the mainland of an area, being connected to it in low tide. In the Caribbean and West Atlantic, islets are often called cays or keys, rum Cay in the Bahamas and the Florida Keys off Florida are examples of islets. In the Channel Islands, they are identified by the suffix -hou from the Norse -holm. In Scotland and Ireland, they are often called inches, from the Gaelic innis, which originally meant island, in Ireland they are often termed skerries. In and around Polynesia, islets are widely known by the term motu, in and around the River Thames in England, small islands are known as aits or eyots. One long-term dispute over the status of such an islet was that of Snake Island, there are thousands of islets on Earth, approximately 24,000 islands and islets in the Stockholm archipelago alone. The following is a list of example islets from around the world, Islands or Rocks, Is that the Real Question. The Treatment of Islands in the Delimitation of Maritime Boundaries, in Myron H. Nordquist, John Norton Moore, Alfred H. A. The Law of the Sea Convention, US Accession and Globalization
7.
Whitewater
–
The term is also loosely used to refer to less turbulent, but still agitated, flows. The term whitewater also has a meaning, applying to any river or creek itself that has a significant number of rapids. The term is used as an adjective describing boating on such rivers. Four factors, separately or in combination, can create rapids, gradient, constriction, obstruction, gradient, constriction and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams, streambed topography is the primary factor in creating rapids, and is generally consistent over time. The gradient of a river is the rate at which it loses elevation along its course and this loss determines the rivers slope, and to a large extent its rate of flow. Shallow gradients produce gentle, slow rivers while steep gradients are associated with raging torrents, constrictions can form a rapid when a rivers flow is forced into a narrower channel. This pressure causes the water to more rapidly and to react differently to riverbed events. As with hydraulics, the power of eddies increases with the flow rate, in large rivers with high flow rates next to an obstruction, eddy walls can occur. An eddy wall is formed when the height of the river is higher than the level of the water in the eddy behind the obstruction. A marked increase or decrease in flow can create a rapid, flow rate is typically measured in cubic metres per second, or in cubic feet per second, depending on the country. The most widely used grading system is the International Scale of River Difficulty, grade-VI rapids are sometimes downgraded to grade-V or V+ if they have been run successfully. Harder rapids are often portaged, a French term for carrying, a portaged rapid is where the boater lands and carries the boat around the hazard. A rapids grade is not fixed, since it may vary depending on the water depth. Although some rapids may be easier at high flows because features are covered or washed-out, high water usually makes rapids more difficult, at flood stage, even rapids which are usually easy can contain lethal and unpredictable hazards. Class 1, Very small rough areas, requires no maneuvering, Class 2, Some rough water, maybe some rocks, small drops, might require maneuvering. Class 3, Medium waves, maybe a 3–5 ft drop, Class 4, Whitewater, large waves, long rapids, rocks, maybe a considerable drop, sharp maneuvers may be needed. Class 5, Whitewater, large waves, continuous rapids, large rocks and hazards, maybe a large drop, often characterized by must make moves, i. e. failure to execute a specific maneuver at a specific point may result in serious injury or death
8.
Egypt
–
Egypt, officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba to the east, the Red Sea to the east and south, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, and across from the Sinai Peninsula lies Saudi Arabia, although Jordan and it is the worlds only contiguous Afrasian nation. Egypt has among the longest histories of any country, emerging as one of the worlds first nation states in the tenth millennium BC. Considered a cradle of civilisation, Ancient Egypt experienced some of the earliest developments of writing, agriculture, urbanisation, organised religion and central government. One of the earliest centres of Christianity, Egypt was Islamised in the century and remains a predominantly Muslim country. With over 92 million inhabitants, Egypt is the most populous country in North Africa and the Arab world, the third-most populous in Africa, and the fifteenth-most populous in the world. The great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres, the large regions of the Sahara desert, which constitute most of Egypts territory, are sparsely inhabited. About half of Egypts residents live in areas, with most spread across the densely populated centres of greater Cairo, Alexandria. Modern Egypt is considered to be a regional and middle power, with significant cultural, political, and military influence in North Africa, the Middle East and the Muslim world. Egypts economy is one of the largest and most diversified in the Middle East, Egypt is a member of the United Nations, Non-Aligned Movement, Arab League, African Union, and Organisation of Islamic Cooperation. Miṣr is the Classical Quranic Arabic and modern name of Egypt. The name is of Semitic origin, directly cognate with other Semitic words for Egypt such as the Hebrew מִצְרַיִם, the oldest attestation of this name for Egypt is the Akkadian
9.
Aswan Low Dam
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The Aswan Low Dam or Old Aswan Dam is a gravity masonry buttress dam on the Nile River in Aswan, Egypt. The dam was built at the former first cataract of the Nile, when initially constructed between 1899 and 1902, nothing of its scale had ever been attempted, on completion, it was the largest masonry dam in the world. The dam was designed to provide storage of floodwater and augment dry season flows to support greater irrigation development. These heightenings still did not meet demands and in 1946 it was nearly over-topped in an effort to maximize pool elevation. This led to the investigation and construction of the Aswan High Dam 6 kilometres upstream, after his field work convinced him of the impracticality of this scheme, and fearing the Caliphs anger, he feigned madness. He was kept under house arrest from 1011 until al-Hakims death in 1021, following their 1882 invasion and occupation of Egypt, the British began construction of the first dam across the Nile in 1898. Construction lasted until 1902, and it was opened on 10 December 1902, by HRH the Duke of Connaught, capital and financing were furnished by Ernest Cassel. The dam was constructed of masonry and faced with red ashlar granite. When constructed, the Old Aswan Dam was the largest masonry dam in the world, at the time of its construction, nothing of such scale had ever been attempted. The first phase was supervised by Sir Benjamin Baker, though much of the work was undertaken by Murdoch MacDonald. With its final raising, the dam is 1,950 metres in length, with a crest level 36 metres above the original riverbed, the dam provides the main route for traffic between the city and the airport. With the construction of the High Dam upstream, the Old Dams ability to pass the floods sediments was lost, the previous Old Dam reservoir level was also lowered and now provides control of tailwater for the High Dam. The Aswan Low Dam supports two hydroelectric plants, Aswan I and Aswan II. Aswan I contains 7 X40 megawatts generators with Kaplan turbines for a capacity of 280 megawatts and is located west of the dam. Aswan II contains 4 x 67.5 megawatts generators for a capacity of 270 megawatts and is located at the toe of the dam. Perennial irrigation and flood protection for Egypt, reports of the Technical Commission on Reservoirs with a note by W. E. Garstin, under Secretary of State, Public Works Department, sidney Peel, The Binding of the Nile and the new Soudan, Oxford 1904. Discusses Assouan Dam and Nile River development, the Assuan Dam, Journal of the Royal African Society, Vol.12, No
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