The River Nile flooded every year between June and September, in a season the Egyptians called akhet - the inundation
This was caused by heavy summer rain in the Ethiopian highlands that sent a torrent of water that overflowed the banks of the Nile. When the floods went down it left thick rich mud (black silt) which was excellent soil to plant in.
The Nile river floods and leaves fertile soil.
It could be good agriculturally, and was since the times of Ancient Egypt, when the floods dumped fertile alluvial soil over the Nile River banks. But it could be bad if the floods were severe, because it would wash away any growing crops. Since the construction of the Aswan High Dam in 1970, Egypt gets no Nile floods, beneficial or otherwise. However, they still occur in Sudan, which is above (south of) the dam.
The Nile River floods every year.
They were farming
The Nile River no longer floods, but when it did it brought extra water and fertile soil.
it made food and produced floods
The Nile River wasn't higher that Tigris and Euphrates, so the Nile River didn't really flood anyting
they made calenders
Silt. The needed this for crops.
Both the Nile Rivers and the rivers of Mesopotamia flooded. The floods of the Nile were very unpredicatable.
Clay for pottery, but more importantly, the floods from the river Nile make the area around the Nile fertile and good for farming many things.
Astronomers could predict when the nile river would flood because they studied the stars and they saw that at the time that the stars got to a certain point that the nile river would flood at that time