It is likely that settlement took place over thousands of years perhaps moving north from the Rift Valley ... and agriculture. In this period people did not need to rely upon the Nile.

Guoqi Wu, the associate vice president for Corporate Services at the International Fund for Agricultural Development (IFAD), ...

It is likely that settlement took place over thousands of years perhaps moving north from the Rift Valley ... and agriculture. In this period people did not need to rely upon the Nile.