man surveys Nile River boat traffic near the Aswan High Dam in Egypt.
The river—one of the world’s longest at 4,225 miles (6,800 kilometers)—runs a south-north course from its headwaters in central Africa to the Mediterranean Sea.
From the Ethiopian highlands to the arid deserts of South Sudan, Sudan, and Egypt, the Nile River and its tributaries have shaped the history and fate of the region’s diverse peoples.
Civilizations were built on the productivity of rich and reliable floodplain agriculture along the Nile. Soil fertility in the river basin traditionally depended on annual floods that washed nutrient-rich sediment onto the riverbanks. Now dams and elaborate irrigation schemes prevent this natural cycle of recharge. While the Aswan High Dam revolutionized Egypt by controlling flooding and making riverbank development less risky, it also prevented silt and natural fertilizers from reaching farm fields, forcing soil degradation and the need for chemical fertilizers.