The longest river in the world, the Nile flows in many countries. Every year, the Nile rises from July to October despite the fact that it hardly rains in Egypt. This is known as “the riddle of the Nile river.”
The Nile, which is 4,008 miles long, flows from the South to the East of Khartoum. There are two rivers making up the Nile: the White Nile and the Blue Nile. The White Nile flows to the South of Khartoum and the Blue Nile winds to its east. After they separate, they meet again at the end to form the Nile.
When the water in the Nile is at its lowest from April and May, 85 percent of the water flows from the White Nile. The Blue Nile rises in Ethiopia, due to of heavy rain in the mountains and melting snow. Both of which flow into the Nile, often causing an overflows. The riddle is then solved: this is precisely why the Nile rises even though it rarely rains in Egypt!
The Nile is important to the Egyptian economy. Many crops are grown and harvested along the river each year using a year-round irrigation system. However, because sub-Saharan countries often suffered from severe droughts, disputes with Egypt and other nations over control and use of the great river are frequent.
Unlike the riddle of where the Nile’s water comes from, the problem of who gets to use the water doesn't have a simple solution. Further negotiations may remedy this issue, Egypt hopes.
[Source: 100 Great Wonders of the World]