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Map of the Blue Nile (in Spanish)

The Blue Nile (Amharic: ዓባይ; transliterated: ʿAbbay, but pronounced Abbay; Arabic: النيل الأزرق; transliterated: an-Nīl al-Āzraq) is a river originating at Lake Tana in Ethiopia. The river is called the Abbay in Ethiopia and the al-Bahr al-Āzraq in Sudan.

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 Gishe Abbai at an altitude of approximately 1800 m (5940 ft). The Blue Nile much later joins the White Nile at Khartoum, Sudan and, as the Nile, flows through Egypt to the Mediterranean Sea at Alexandria. The Blue Nile is so-called because its water is visibly purer for most of the year than the grey-coloured water of the White Nile.

The distance from its source to its confluence is variously reported as 1460 and 1600 km (907 and 1000 mi). The uncertainty over its length might partially result from the fact that it flows through virtually impenetrable gorges cut in the Ethiopian highlands to a depth of some 1500 m (4950 ft)—a depth comparable to that of the Grand Canyon in the United States.

The Blue Nile Falls fed by Lake Tana near the city of Bahir Dar, Ethiopia forms the upstream of the Blue Nile. It is also known as Tis Issat Falls after the name of the nearby village.

At the confluence of the White Nile and Blue Nile, as shown in this image of central Khartoum from Google Earth, the water of the Blue Nile (right) can be seen to be visibly darker than that of the White Nile (bottom).

The Blue Nile flows generally south from Lake Tana and then west across Ethiopia and northwest into Sudan. Within 30 km (18.6 mi) of its source at Lake Tana, the river enters a canyon about 400 km long. This gorge is a tremendous obstacle for travel and communication from the north half of Ethiopia to the southern half. The power of the Blue Nile may best be appreciated at Tis Issat Falls, which are 45 m (148 ft) high, located about 40 km (25 mi) downstream of Lake Tana.

The flow of the Blue Nile reaches maximum volume in the rainy season (from June to September), when it supplies about two thirds of the water of the Nile proper. The Blue Nile, along with that of the Atbara River to the north, which also flows out of the Ethiopian highlands, were responsible for the annual Nile floods that contributed to the fertility of the Nile Valley and the consequent rise of ancient Egyptian civilization and Egyptian Mythology. With the completion in 1970 of the Aswan High Dam in Egypt, the Nile floods ended.

It is generally believed that the first European to have seen the Blue Nile in Ethiopia was Pedro Paez, a Spanish Jesuit who traveled to the area in the early 1600s; however, John Bermudez provided a description of the Tis Issat Falls in his memoirs (published in 1565), and a number of Europeans who lived in Ethiopia in the late 15th century like Pero da Covilhã could have seen the river. The first European to actually navigate the Blue Nile from Lake Tana to the Nile Delta was James Bruce, a Scottish explorer, who undertook the journey in the 1770s.

The Blue Nile is vital to the livelihood of Egypt. Though shorter than the White Nile, 56% of the water that reaches Egypt originates from the Blue Nile branch of the great river; when combined with the Atbara River, which also has its source in the Ethiopian Highlands, the figure rises to 90% of the water and 96% of transported sediment.^[1] The river is also an important resource for Sudan, where the Roseires and Sennar dams produce 80% of the country's power. These dams also help irrigate the Gezira Plain, which is most famous for its high quality cotton. The region also produces wheat, and animal feed crops.

On April 28, 2004, geologist Pasquale Scaturro and his partner, kayaker and documentary filmmaker Gordon Brown, became the first people since Bruce 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 IMAX film Mystery of the Nile and in a book of the same title. Despite this attempt, the team was forced to use outboard motors for most of their journey, and it was not until January 29, 2005, when Canadian Les Jickling and New Zealander Mark Tanner reached the Mediterranean Sea, that the river had been paddled for the first time under human power.

1. ^ Marshall et al., Late Pleistocene and Holocene environmental and climatic change from Lake Tana, source of the Blue NilePDF (247 KiB), 2006

Wikimedia Commons has media related to:

Blue Nile

• The Blue Nile Falls
• Rafting Down the Blue Nile