The longest river in the world is the Nile, with a total length of 6670 kilometers. The Nile is a river that flows through Eastern and northern Africa and flows into the Mediterranean from south to north. The Congo River in Central Africa and the Niger River in West Africa are the three largest river systems in Africa.
The Nile River is characterized by regular flooding. In northern Sudan, it usually begins to rise in May, reaches the highest water level in August, and then the water level gradually decreases, with a low water level from January to May. Although floods occur regularly, the amount of water and the time of high tide change greatly. The reason for this phenomenon is the Blue Nile and Atbara rivers. The water sources of these two rivers come from seasonal rainstorms on the Ethiopian plateau.
More than 80% of the Nile River water is provided by the Ethiopian plateau, and the rest comes from the East African plateau lake. When the flood comes, it will flood the farmland on both banks. When the flood recedes, it will leave a thick layer of silt to form fertile soil.
Four or five thousand years ago, Egyptians knew how to master the law of floods and make use of the fertile land on both sides of the Strait. For a long time, the Nile Valley has been full of cotton fields and fragrant rice flowers. Between the Sahara desert and the Arabian desert, the winding Nile is like a green outline, full of infinite vitality.