(2 of 2)
> The Neonile, or present river, emerged a mere 30,000 years ago. Fed, like its predecessor, from rains on the East African plateau, the river is the only major source of water in a virtually rainless country. Before the High Dam was built, the river dropped substantially during the winter and rose to flood levels during the summer.
Said believes that the behavior of the fifth Nile led to many of the accomplishments of Egyptian civilization. Man made his appearance in the Nile Valley toward the end of the period between the death of the Prenile and the birth of its successor, and had to adapt to the river in order to survive. He rose to the challenge superbly. The ancient Egyptians developed geometry so that they could mark out landholdings and lay out irrigation ditches; they invented a practical calendar to keep track of the seasons, and created a government to coordinate their attempts to cope with the forces of nature.
Now the Nile again seems to be in the process of change. Its delta is eroding (it has receded some seven miles since 1878). The erosion has been accelerated by the Aswan High Dam, which holds back silt that was once deposited in the valley and the delta. Free of silt, the river below the dam is flowing more swiftly and eating away its bed.
In 20 years, Said believes, the river banks may begin to collapse unless measures are taken to shore them up.