Why is Egypt called the gift of the Nile?

Well, what i have read, the nile in certain season of the year, it overflows. Afterwards the water of the nile goes back to the river, however it left the land that it overflowed, rich with minerals that is ideal to plant crops and food for the Egyptians to survive. With out the nile river, the Egyptians would not have survive at all. Hope this helps.