The river dominated the land all around it. Life away from the Nile was almost unthinkable to the Egyptians.
The Nile is the life source of Egypt. Every year, the Nile would flood the neighbouring farms, and enrich it's soil. And in turn, would bring a good harvest of crops, and wealth to the land.
The river's mysterious behaviour fluctuation was so critical for the survival of Egypt, that it was associated with divine power. It obviously had a mind of it's own, therefore, it could be satisfied, offered to, and even worshipped. In the instance
Aside from the annual flooding, the Nile provided a gateway for easy transportation and also a great supply of fish.