Demonstrates the sharp transition between arid desert and fertile land watered by the Nile. Only 3.5% of the total land area of Egypt is cultivated and permanently settled so that the Nile valley and Delta support 99% of the population. In Ancient Egypt, the annual flooding of the Nile (usually in August and September) was seen as a gift from the Gods designed to ensure continuity of life. The silt bourne by the river renewed and enriched the soil. The construction of the Aswan High Dam in 1964 made possible the reclamation of about 650,000 feddans (a feddan is 1,038 acres) and brought 880,000 feddans under perennial irrigation although it left much of the fertile silt behind it, in Lake Nasser.