Why did the ancient Egyptians believed the Nile river flooded?

Most Egyptologists will tell you that there is no Egyptian flood myth. Certainly, there is no equivalent to the world-destroying deluge tales found in some other cultures. Part of the reason for this is that the annual Nile inundation was viewed as essential to agricultural success and the fertility of the land.

The closest we come to a flood myth is a mid second millennium BCE composition

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