Why was the yearly flood important in Ancient Egypt?

Answer 1

Every year, heavy summer rain in the Ethiopian highlands, sent a torrent of water that overflowed the banks of the Nile. This left thick rich mud (black silt) which was excellent soil to plant seeds in. The ancient Egyptians could grow crops only in the mud left behind when the Nile flooded. So they all had fields all along the River Nile.

Answer 2

When the water goes onto the flood plain, it deposits many essential nutrients and minerals into the soil. This means that the soils are more fertile and agriculture is more successful.

Answer 3

The Nile's water has rich silt in it, so when the Nile floods it washes the silt up onto the land, which fertilized the land and helped them grow cotton, wheat, barley, etc.