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 80% of the water in 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  —a depth comparable to that of the Grand Canyon of the Colorado River in the United States. According to materials published by the Central Statistical Agency, the Blue Nile has a total length of , of which are inside Ethiopia. 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 Ethiopia. The canyon was first referred to as the "Grand Canyon" in 1968 by a British  team that accomplished the first descent of the river from Lake Tana to the end of the canyon; subsequent river rafting parties called it the "Grand Canyon of the Nile". The Blue Nile Falls (Amharic: Tis Abay, literally "great smoke"), one of Ethiopia's biggest tourist attractions, is located at the start of the canyon. The river loops across northwest Ethiopia, before being fed by numerous tributaries between Lake Tana and the Ethiopia–Sudan border. Those on its left bank, in downstream order, include the Wanqa River, the Bashilo River, the Walaqa River, the Wanchet River, the Jamma River, the  Muger River, the Guder River, the Agwel River, the Nedi River, the Didessa River and the Dabus River. Those on the right side, also in downstream order, include the Handassa, Tul, Abaya, Sade, Tammi, Cha, Shita, Suha, Muga, Gulla, Temcha, Bachat, Katlan, Jiba, Chamoga, Weter and the Beles. Sudan. The Blue Nile then heads northwest into Sudan. It travels for approximately , flowing past Er Roseires and receiving the Dinder River on its right bank at Dinder. At Khartoum, the Blue Nile joins the White Nile and, as the Nile, flows through Egypt to the Mediterranean Sea at Alexandria. Source. Although  there are several feeder streams that flow into Lake Tana, the sacred source of the river is generally considered to be a small spring at Gish Abay, situated at an elevation of approximately , known as the Gilgel Abay (Lesser Abay River). Other affluents of this lake include the Magech River, the Northern Gumara, the Reb River, the southern Gumara River, and the Kiltie. Water flow. The flow of the Blue Nile reaches maximum volume in the rainy season from June to September, when it supplies 8086% of the water of the Nile proper. The river was a major source of  the flooding of the Nile in Egypt that contributed to the fertility of the Nile Valley and the consequent rise of Ancient Egypt and Egyptian mythology. With the completion of the Aswan Dam in 1970, these floods stopped occurring in lower Egypt. During the summer monsoon season, the Blue Nile floods erode a vast amount of fertile soil from the Ethiopian Highlands and carry it downstream as silt, turning the water dark brown or almost black. The Blue Nile is vital to the livelihood of Egypt: as the most significant tributary of the Nile, it contributes over 85% of the  Nile's streamflow. Though shorter than the White Nile, 59% of the water that reaches Egypt originates from the Ethiopian highlands via the Blue Nile. The river is also an important resource for Sudan, where the Roseires Dam and Sennar Dams produce 80% of the country's power. These dams also help irrigate the Gezira Scheme, which is most famous for its high-quality cotton, as well as wheat and animal feed crop production in the area. In November 2012, Ethiopia began construction of the Grand Ethiopian Renaissance Dam, a 6000-megawatt hydroelectric dam on the river. The dam is  expected to be a boost for the Ethiopian economy. Sudan and Egypt, however, voiced their concerns over a potential reduction in water available. Electricity generation began in February 2022. European exploration. The first European known to have seen the Blue Nile in Ethiopia and the river's source was Pedro Páez, a Spanish Jesuit who reached the river's source on 21 April 1618. However, the Portuguese João Bermudes, the self-described "Patriarch of Ethiopia," provided the first description of the Tis Abay River Falls in his memoirs published in 1565, and a number of Europeans who lived in Ethiopia  in the late 15th century such as Pêro da Covilhã could have seen the river long before Páez, but not reached its source. The source of the Nile proper was also reached in 1629 by the Portuguese Jesuit missionary Jerónimo Lobo and in 1770 by the Scottish explorer James Bruce. Although a number of European explorers contemplated tracing the course of the Nile from the Blue Nile's confluence with the White Nile to Lake Tana, its gorge, which begins a few kilometers inside the Ethiopian border, has discouraged all attempts since Frédéric Cailliaud's attempt in 1821. The first  serious attempt by a non-local to explore this reach of the river was undertaken by the American W.W. Macmillan in 1902, assisted by the Norwegian explorer B.H. Jenssen; Jenssen would proceed upriver from Khartoum while Macmillan sailed downstream from Lake Tana. However, Jenssen's boats were blocked by the rapids at Famaka short of the Sudan-Ethiopia border, and Macmillan's boats were wrecked shortly after they had been launched. Macmillan encouraged Jenssen to try to sail upstream from Khartoum again in 1905, but he was forced to stop short of Lake Tana. R.E. Cheesman, who records his surprise  on arriving in Ethiopia at finding that the upper waters of "one of the most famous of the rivers of the world, and one whose name was well known to the ancients" was in his lifetime "marked on the map by dotted lines", managed to map the upper course of the Blue Nile between 1925 and 1933. He did this not by following the river along its banks and through its impassable canyon, but following it from the highlands above, travelling some by mule in the adjacent country. In the 1950s and 1960s, several kayakers paddled parts of the canyon . In 1968, at the request of Haile Selassie, a team of 60 British and Ethiopian servicemen and scientists made the first full descent of the river from Lake Tana to a point near the Sudanese border led by explorer John Blashford-Snell. The team used specially-built Avon Inflatables and modified Royal Engineers assault boats to navigate the formidable rapids. Subsequent rafting expeditions in the 1970s and 1980s generally only covered parts of the river canyon. In 1999, writer Virginia Morell and photographer Nevada Wier made the journey by raft from Lake Tana to Sudan, publishing a documentary about their  journey afterwards. In 2000, American and National Geographic reader, Kenneth Frantz, saw a photo taken by Nevada Wier for "National Geographic" which would lead him to found the charity Bridges to Prosperity. This photo showed a bridge broken during World War II, with 10 men on either side of the broken span pulling each other across the dangerous gap by rope. This historic bridge was built by Emperor Fasilides in approximately 1660 with Roman bridge technology brought to Ethiopia by Portuguese soldiers during the battle with the Muslim invaders in 1507. In both 2001 and 2009, Bridges to Prosperity volunteers  travelled from the United States to repair the broken bridge across the Blue Nile and later built a new suspension bridge not susceptible to flood. On 28 April 2004, geologist Pasquale Scaturro and his partner, kayaker and documentary filmmaker Gordon Brown, became the first known people to navigate the Blue Nile. Though their expedition included a number of others, Brown and Scaturro were the only ones to remain on the expedition for the entire journey. They chronicled their adventure with an IMAX camera and two handheld video cams, sharing their story in the film "Mystery of the Nile" and in  a book of the same title. On 29 January 2005, Canadian Les Jickling and his teammate New Zealander Mark Tanner completed the first fully human-powered transit of the entire Blue Nile and the Nile in the Sudan and Egypt. Their journey of over took five months and traveled through Ethiopia, Sudan, and Egypt. They recount that they paddled through civil war conflict zones, regions known for bandits, and encountered multiple hazards and rapids.