The Nile River meanders through 11 countries, supplying water to hundreds of millions of people. New studies suggest that flows from the Nile to Egypt could decrease by up to 25%, with catastrophic effects on the country's coastal ecosystem and economy.
The Nile is considered the longest river in the world: it is formed by two large confluent branches, the White Nile and the Blue Nile. The White Nile originates from Lake Victoria, then flows north into Uganda and southern Sudan.
The Blue Nile instead originates from Lake Tana in Ethiopia, and flows through south-eastern Sudan. The two rivers meet and merge in the Sudanese capital Khartoum. The northern course of the river flows almost entirely through the Sahara, from Sudan to Egypt, a country whose civilization has depended on the river since ancient and more remote times.
Eventually the Nile branches into a large delta and flows into the Mediterranean Sea. His Strahler number is 10. From its sources to the delta, the Nile crosses seven African countries: Burundi, Rwanda, Tanzania, Uganda, South Sudan, Sudan and Egypt, but its drainage basin includes portions of the Democratic Republic of the Congo, Kenya, Ethiopia and Eritrea.
The water flow of the Nile in South Sudan is constant throughout most of the year and the average is 1 048 m³ / s. Past the city of Mongalla the Nile, which becomes known as Bahr al-Jabal, enters a huge swampy region called Sudd in South Sudan.
More than half of the Nile's waters are lost in these swamps due to evaporation and filtration in the soil. The water flow of the Bahr al-Jabal drops dramatically to around 510 m³ / s. From here it will soon meet the Sobat River and give shape to the White Nile itself.
The Nile still supports much of the population living along its banks, especially in otherwise inhospitable regions such as the Sahara Desert. The river overflowed every summer, depositing fertile silt in the plains. The course of the river is hindered in several places by the presence of the cataracts, which are sections in which the water flows more rapidly and in which there can be many small islands, and outcropping rocks, which in fact constitute an obstacle to the navigation of boats.
The river is currently very exploited also from the point of view of tourism with the proposal of countless types of cruises along its course. Among the characteristic boats with which they are carried out, the Dahabeya can be mentioned.
The Aswan dam and the consequent blockage of sediment transport is one of the causes of the progressive erosion of the wide Nile delta.